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BACKGROUND OF THE INVENTION
This invention relates to medical implants formed of a polymeric material such as ultra-high molecular weight polyethylene (UHMWPE), with superior oxidation and wear resistance produced by an irradiation process. The UHMWPE is doped with the anti-oxidant anthocyanin.
Various polymer systems have been used for the preparation of artificial prostheses for biomedical use, particularly orthopedic applications. Among them, ultra-high molecular weight polyethylene is widely used for articulation surfaces in artificial knee, hip, and other joint replacements. Ultra-high molecular weight polyethylene (UHMWPE) has been defined as those linear polyethylenes which have a relative viscosity of 2.3 or greater at a solution concentration of 0.05% at 135° C. in decahydronaphthalene. The nominal weight—average molecular weight is at least 400,000 and up to 10,000,000 and usually from three to six million. The manufacturing process begins with the polymer being supplied as fine powder which is consolidated into various forms, such as rods and slabs, using ram extrusion or compression molding. Afterwards, the consolidated rods or slabs are machined into the final shape of the orthopedic implant components. Alternatively, the component can be produced by compression molding of the UHMWPE resin powder.
All components must then go through a sterilization procedure prior to use, but usually after being packaged. There exist several sterilization methods which can be utilized for medical applications, such as the use of ethylene oxide, gas plasma, heat, or radiation. However, applying heat to a packaged polymeric medical product can destroy either the integrity of the packaging material (particularly the seal, which prevents bacteria from going into the package after the sterilization step) or the product itself.
It has been recognized that regardless of the radiation type, the high energy beam causes generation of free radicals in polymers during radiation. It has also been recognized that the amount or number of free radicals generated is dependent upon the radiation dose received by the polymers and that the distribution of free radicals in the polymeric implant depends upon the geometry of the component, the type of polymer, the dose rate, and the type of radiation beam. The generation of free radicals can be described by the following reaction (which uses polyolefin and gamma ray irradiation for illustration):
Depending on whether or not oxygen is present, primary free radicals r• will react with oxygen and the polymer according to the following reactions as described in “Radiation Effects on Polymers,” edited by Roger L. Clough and Shalaby W. Shalaby, published by American Chemical Society, Washington, D.C., 1991.
In the Presence of Oxygen
In radiation in air, primary free radicals r• will react with oxygen to form peroxyl free radicals rO 2 ., which then react with polyolefin (such as UHMWPE) to start the oxidative chain scission reactions (reactions 2 through 6). Through these reactions, material properties of the plastic, such as molecular weight, tensile and wear properties, are degraded.
It has been found that the hydroperoxides (rOOH and POOH) formed in reactions 3 and 5 will slowly break down as shown in reaction 7 to initiate post-radiation degradation. Reactions 8 and 9 represent termination steps of free radicals to form ester or carbon-carbon cross-links. Depending on the type of polymer, the extent of reactions 8 and 9 in relation to reactions 2 through 7 may vary. For irradiated UHMWPE, a value of 0.3 for the ratio of chain scission to cross-linking has been obtained, indicating that even though cross-linking is a dominant mechanism, a significant amount of chain scission occurs in irradiated polyethylene.
By applying radiation in an inert atmosphere, since there is no oxidant present, the primary free radicals r• or secondary free radicals P• can only react with other neighboring free radicals to form carbon-carbon cross-links, according to reactions 10 through 12 below. If all the free radicals react through reactions 10 through 12, there will be no chain scission and there will be no molecular weight degradation. Furthermore, the extent of cross-linking is increased over the original polymer prior to irradiation. On the other hand, if not all the free radicals formed are combined through reactions 10, 11 and 12, then some free radicals will remain in the plastic component.
In an Inert Atmosphere
It is recognized that the fewer the free radicals, the better the polymer retains its physical properties over time. The greater the number of free radicals, the greater the degree of molecular weight and polymer property degradation will occur. Applicant has discovered that the extent of completion of free radical cross-linking reactions is dependent on the reaction rates and the time period given for reaction to occur.
UHMWPE is commonly used to make prosthetic joints such as artificial hip joints. In recent years, it has been found that tissue necrosis and interface osteolysis may occur in response to UHMWPE wear debris. For example, wear of acetabular cups of UHMWPE in artificial hip joints may introduce microscopic wear particles into the surrounding tissues.
Improving the wear resistance of the UHMWPE socket and, thereby, reducing the rate of production of wear debris may extend the useful life of artificial joints and permit them to be used successfully in younger patients. Consequently, numerous modifications in physical properties of UHMWPE have been proposed to improve its wear resistance.
It is known in the art that ultra-high molecular weight polyethylene (UHMWPE) can be cross-linked by irradiation with high energy radiation, for example gamma radiation, in an inert atmosphere or vacuum. Exposure of UHMWPE to gamma irradiation induces a number of free-radical reactions in the polymer. One of these is cross-linking. This cross-linking creates a 3-dimensional network in the polymer which renders it more resistant to adhesive wear in multiple directions. The free radicals formed upon irradiation of UHMWPE can also participate in oxidation which reduces the molecular weight of the polymer via chain scission, leading to degradation of physical properties, embrittlement and a significant increase in wear rate. The free radicals are very long-lived (greater than eight years), so that oxidation continues over a very long period of time resulting in an increase in the wear rate as a result of oxidation over the life of the implant.
Sun et al. U.S. Pat. No. 5,414,049, the teachings of which are incorporated herein by reference, broadly discloses the use of radiation to form free radicals and heat to form cross-links between the free radicals prior to oxidation.
Hyun et al. U.S. Pat. No. 6,168,626 relates to a process for forming oriented UHMWPE materials for use in artificial joints by irradiating with low doses of high-energy radiation in an inert gas or vacuum to cross-link the material to a low degree, heating the irradiated material to a temperature at which compressive deformation is possible, preferably to a temperature near the melting point or higher, and performing compressive deformation followed by cooling and solidifying the material. The oriented UHMWPE materials have improved wear resistance. Medical implants may be machined from the oriented materials or molded directly during the compressive deformation step. The anisotropic nature of the oriented materials may render them susceptible to deformation after machining into implants.
Salovey et al. U.S. Pat. No. 6,228,900, the teachings of which are incorporated by reference, relates to a method for enhancing the wear-resistance of polymers, including UHMWPE, by cross-linking them via irradiation in the melt.
Saum et al. U.S. Pat. No. 6,316,158 relates to a process for treating UHMWPE using irradiation followed by thermally treating the polyethylene at a temperature greater than 150° C. to recombine cross-links and eliminate free radicals.
Several other prior art patents attempt to provide methods which enhance UHMWPE physical properties. European Patent Application 0 177 522 81 relates to UHMWPE powders being heated and compressed into a homogeneously melted crystallized morphology with no grain memory of the UHMWPE powder particles and with enhanced modulus and strength. U.S. Pat. No. 5,037,928 relates to a prescribed heating and cooling process for preparing a UHMWPE exhibiting a combination of properties including a creep resistance of less than 1% (under exposure to a temperature of 23° C. and a relative humidity of 50% for 24 hours under a compression of 1000 psi) without sacrificing tensile and flexural properties. U.K. Patent Application GB 2 180 815 A relates to a packaging method where a medical device which is sealed in a sterile bag, after radiation/sterilization, is hermetically sealed in a wrapping member of oxygen-impermeable material together with a deoxidizing agent for prevention of post-irradiation oxidation.
U.S. Pat. No. 5,153,039 relates to a high density polyethylene article with oxygen barrier properties. U.S. Pat. No. 5,160,464 relates to a vacuum polymer irradiation process.
In addition to cross-linking via a stabilization or annealing process, it is possible to chemically cross-link the polyethylene. However, when implanting a polyethylene in the human body it is necessary to chemically cross-link with a non-toxic chemical. U.S. Pat. No. 5,827,904 relates to the use of a carotenoid doped into a powder base or stock solid polyethylene material to produce a stabile oxidation resistant matrix for use in medical implants. U.S. Pat. No. 6,277,390 teaches the use of vitamin E (alpha-tocopherol) to protect from irradiation damage. U.S. Patent Application Publication No. 2006/0264541 and U.S. Patent Application Publication No. 2007/0059334 also relate to utilizing vitamin E to stabilize UHMWPE. U.S. Pat. No. 6,448,315 relates to a method using CO 2 under super critical fluid conditions at elevated temperatures and pressures to dope the UHMWPE with vitamin E. Sequentially irradiating and annealing is taught in U.S. Patent Publication No. 2005/0043431. U.S. Patent Application Publication No. 2005/0194723 also relates to methods for making medical devices having vitamin E diffused therein.
SUMMARY OF THE INVENTION
The present invention relates to a method for providing a polymeric material, such as UHMWPE, with superior oxidation resistance, mechanical strength and wear properties. For the purpose of illustration, UHMWPE will be used as an example to describe the invention. However, all the theories and processes described hereafter should also apply to other polymeric materials such as polypropylene, high density polyethylene, polyhydrocarbons, polyester, nylon, polyurethane, polycarbonates and poly(methylmethcrylate) unless otherwise stated. The method involves using a series of relatively low doses of radiation with an annealing process after each dose.
As stated above, UHMWPE polymer is very stable and has very good resistance to aggressive media except for strong oxidizing acids. Upon irradiation, free radicals are formed which cause UHMWPE to become activated for chemical reactions and physical changes. Possible chemical reactions include reacting with oxygen, water, body fluids, and other chemical compounds while physical changes include density, crystallinity, color, and other physical properties. In the present invention, an anthocyanin compound is used to eliminate the free radicals during irradiation. Furthermore, this process does not employ stabilizers, antioxidants, or any other chemical compounds which may have potentially adverse effects in biomedical or orthopedic applications.
An orthopedic preformed material such as a rod, bar or compression molded sheet for the subsequent production of a medical implant such as an acetabular or tibial implant with improved wear resistance is made from a polyethylene material doped with an anthrocyanin in a concentration of up to 5% wt/wt. The material is cross-linked by a total radiation dose of from about 2 MRads to 100 MRads and preferably between 5 MRads and 15 MRads and most preferably 9-12 MRads.
The polyethylene of the present invention may be in the form of a preformed rod or sheet with a subsequent production of a medical implant with improved wear resistance. The preformed rod or sheet doped with an anthrocyanin is cross-linked by irradiation one or more times. The preferred method is to apply the radiation dose in increments, the incremental dose for each radiation is preferably between about 2 and 5 MRads with the total dose between 2 and 100 MRads and preferably between 5 and 21 MRads and most preferably 9 and 12 MRads.
A first method of forming a cross-linked ultra-high molecular weight polyethylene blend comprises: combining an anthocyanin material and ultra-high molecular weight polyethylene to form a doped ultra-high-molecular weight polyethylene; and sequentially irradiating the ultra-high molecular weight polyethylene blend with electron-beam or gamma ray radiation to a total dose of at least about 2 MRad and preferably 9-12 MRads to form a cross-linked ultra-high-molecular weight polyethylene blend. The amount of anthocyanin combined in the blend is preferably between about 0.002 w/w % and about 2.0 w/w %. Even more preferably the amount of anthocyanin combined in the blend is between about 0.005 and about 0.4 w/w %.
The preferred method further comprises the step of heating the ultra-high molecular weight polyethylene doped with anthocyanin after each irradiation. Preferably the temperature is between 110° C. and 130° C. but less than the melting point for about 8 hours. This sequential radiation and annealing process is taught in U.S. Patent Publication No. 2004/0043431, the disclosure of which is incorporated herein by reference. The cross-linked ultra-high molecular weight doped polyethylene may be formed into an implant such as by molding. The implant is sterilized during or subsequent to irradiating. Preferably the sterilizing step comprises contacting the implant with electron-beam radiation, gamma radiation, gas plasma or ethylene oxide. After sterilization the implant is packaged in a sterile container. The sterilizing step may occur during, after or both during and after packaging the implant. The ultra high molecular weight polyethylene doped with anthocyanin is a substantially uniform blend.
A second method of forming a sterilized packaged implant comprises: forming an implant from a resin blend of ultra-high molecular weight polyethylene and anthocyanin such as by molding or extrusion and then packaging the implant. The packaged implant is then irradiated with electron-beam radiation to a total dose of at least about 2 MRad and preferably 9 to 12 MRads at a dose rate of at least about 0.5 MRAD per hour. The irradiation may be done in one step or preferably sequentially. Preferably the implant is packaged in an oxygen-deprived barrier package and the ultra-high molecular weight doped polyethylene is a substantially uniformly blended mixture.
The methods produce a load bearing medical implant, comprising: a solid UHMWPE material; and a sufficient amount of anthocyanin compound doped into the polymeric solid material to produce a stable, oxidation resistant, matrix for forming the medical, load bearing implant. The anthocyanin compound is preferably present in a range of from 0.002 w/w % amounts to 2% by weight. The blended resin composition may be formed into a polymeric solid material in a rod bar or block stock form by extrusion or preferably by molding. The implant made of the UHMWPE is machined out of UHMWPE blocks or extruded bars or rods, wherein anthocyanin is dispersely imbedded in the polyethylene with a preferred concentration K of 0.002%<K<2%. The doped implant is exposed to gamma ray or electron beam irradiation amounts of at least about 2.0 MRad to prevent the implant from becoming brittle in the long term and improve wear properties.
The implant may be manufactured from doped UHMWPE, where the implants have been machined out of doped UHMWPE blocks or extruded bars or rods, wherein anthocyanin is dispersely imbedded in the polyethylene with a concentration K of 0.002%<K<2%, the implant being exposed to gamma ray or electron beam irradiation in amounts of 9 to 12 MRad and annealed after irradiation. Preferably this is done sequentially as described in U.S. Patent Publication No. 2004/0043431. The anthocyanin prevents the implant from becoming brittle in the long term and thereby wear and tear at contact locations. The inclusion of anthocyanin is preferably by mixing a powder or granulate of UHMWPE with an aqueous liquid such as deionized water that contains anthocyanin (which is water soluble) in a predetermined amount. The water is evaporated in order to deposit the anthocyanin in a predetermined concentration on the polyethylene particles. The polyethylene particles are compressed into blocks at temperatures in a range of approximately 135° C.-250° C. and pressures in a range of approximately 2-70 MPa.
The preformed doped polyethylene material is then machined into a medical implant or other device. If the irradiation process takes place in air, then the entire outer skin to about 2 mm deep is removed from the preform prior to machining the medical implant or other device. If the process is done in a vacuum or an inert atmosphere such as nitrogen, then the outer skin may be retained.
The end-results of reduced chain-scission and free-radical concentration are improved mechanical properties, improved oxidation resistance and enhanced wear resistance.
DETAILED DESCRIPTION
Anthocyanins are water soluble naturally occurred products. They are present in plants, flowers, fruits such as grapes, berries and in red wine. Anthocyanins are natural pigments that appear red, purple to blue according to pH. Importantly, anthocyanins act as powerful antioxidants to protect the plant from free radical induced oxidation. Their antioxidant capacity could be up to 4 times higher than Vitamin E. Anthocyanins have also been found to have anti-imflammability, anti-angiogenic and anti-carcinogenic properties. Currently anthocyanins are widely used in the food industry.
Two anthocyanin extracts in powder form from grape skin (Antho-G) and bilberry (Antho-B) respectively and a total of four concentrations were tested: The anthocyanin extract (Antho-G) from grape skin was obtained from Food Ingredient Solution LLC as a food additive. Anthocyanin content in the grape extract is about 8%. The anthocyanin extract from bilberry (Antho-B) was obtained from Charles Bowman and Company and anthocyanin content in the bilberry extract is 50%.
The anthocyanin extract used was obtained as a red powder. In the preferred method the red powder was dissolved in water at appropriate concentrations. A solution of 2.5% of either extract was used. The mixing formed a red aqueous solution. Typically, 16 ml of the 2.5% solution of either Antho-G or Antho-B was added to 800 g UHMWPE powder and the mixture was blended using a Papenmeier shear blender. The doped powder wet mixture (light pink depending on the concentration of anthocyanin) was dried under nitrogen and then consolidated at 350° F., with a maximum unit pressure of approximately 1000 psi (34 MPa). A pinkish colored UHMWPE block in a size of 2×3×6 inches was obtained in a custom Wabash 4 opening press.
Alternately, 0.4 grams of dry anthocyanin (Ortho-G or Antho-B) red powder could be blended with 800 UHMWPE powder. This will result in a similar colored UHMWPE powder as was obtained with the wet blended powder. Molding would be performed as described above.
The content of anthocyanin in the UHMWPE may be up to 5% by weight and preferably 0.005 to 2% by weight. The color of the UHMWPE got deeper from pink to dark red with an increase of anthocyanin content.
The UHMWPE may be formed into a block by compression molding and the block with anthocyanin was gamma irradiated at an approximately 9 MRad in three steps with annealing after each step of cumulated doses. The color of the UHMWPE was visually examined and no color change was observed.
EXAMPLE
Gur 1020 brand UHMWPE powder per ASTM F 648 Type I was purchased from Ticona GmbH, FrankfurtMain, Germany. The partial size of the powder was less than 300 μm.
The anthocyanin Antho-G and Antho-B extracts were dissolved in water in a concentration of 2.5% and mixed into the UHMWPE powder using a Papenmeier shear blender. The amount of the 2.5% solution added to the UHMWPE powder was varied to produce either 500 ppm (0.05% w/w) or 250 ppm (0.025% w/w) of the antho-G extract or 250 or 125 ppm of the antho-B extract. The actual concentration of anthocyanin contained in each sample is shown in Table 1. After drying under nitrogen, the UHMWPE blend was then molded at 350° F. and with a maximum unit pressure of approximately 1000 psi (4 MPa) to produce a test sample plaque in a size of 2×3×6 inches.
The anthocyanin doped plaques were sequentially gamma irradiated 3 MRad for a total dose of 9 and annealed after each dose at 130° C. for 8 hours. Test samples (1 mm slices) were then machined out of the treated blocks and tested according to the ASTM standard methods.
The density measurements were determined according to ASTM D1505 using density gradient column. Two (2) specimens per sample were evaluated. Average value and standard deviation are reported.
Crystallinity measurements were obtained in accordance with ASTM D3418. Standard testing on Perkin-Elmer Diamond DSC was used. Both heating and cooling runs were performed at 10° C./min. The peak temperature on the heating and the cooling curves determined the melting point and the crystallization temperature, respectively. The crystallinity was calculated as the heat of fusion of the test specimen divided by 287.3 J/g (the heat of fusion for a perfect PE crystal). Five (5) specimens per sample were analyzed; the average value and standard deviation are reported. A virgin GUR 1020 sample was included in every run for control. The results of the analysis are shown in Table 1.
The tensile test was conducted according to ASTM D638 (Reference 3), Type IV with a crosshead speed set at 5.08 cm/min (or 2 in/min). A standard tensile tester (Instron 4505) was used. Eight specimens per sample condition were tested; the average value and standard deviation are reported for yield strength, ultimate strength and elongation. The results are shown in Table 1.
TABLE 1
Physical and mechanical properties of anthocyanin UHMWPE
Antho-G
Antho-G
Antho-B
Antho-B
500 ppm
250 ppm
250 ppm
125 ppm
Material
Undoped
of
of
of
of
Property
Reference
Extract
Extract
Extract
Extract
Density,
939
938
939
937
939
kg/m3
Crystallinity
59.2 ± 1.2
58.6 ± 0.7
61.2 ± 3.4
57.3 ± 0.1
59.0 ± 0.8
(*) %
Tensile
23.8 ± 0.2
24.2 ± 0.2
24.1 ± 0.2
23.9 ± 0.2
23.5 ± 0.3
Yield
Strength,
MPa
Tensile
54.0 ± 4.4
52.9 ± 3.5
56.6 ± 2.4
58.2 ± 2.9
55.3 ± 3.5
Ultimate
Strength,
MPa
Tensile
268 ± 13
262 ± 12
272 ± 7
278 ± 8.8
270 ± 9.2
Elongation at
Break, %
Anthocyanin
0
40 PPM
20 PPM
125 PPM
62.5 PPM
con-
centration
(PPM)
Physical and mechanical properties of the anthocyanin doped UHMWPE are shown in Table 1. The data indicate that addition of the anthocyanin extract resulting in either a 125, 250 ppm (0.0125% w/w) or 500 ppm (0.05% w/w) concentration of extract in the GUR 1020 did not affect the physical and mechanical properties.
Free radical measurements were conducted at the Department of Physics, The University of Memphis. The experiment procedures are as follows: Following machining/cutting, each sample was cleaned in ethanol and dried in a drying environment using filtered dry nitrogen. However, precut/pre-machined, cleaned and prepackaged samples are used without any additional cleaning. Before measurements, the mass of each sample was recorded using a microgram scale (GA 110, Ohaus). The sample for measurement was placed in a high purity suprasil quartz tube of size 4 mm outer and 3 mm inner diameters, and varying between 100 and 200 mm in length (Wilmad Glass). Along with each sample, a reference standard (SRM 2601, NIST) was also placed in the tube. For free radical measurements, an X-band electron spin resonance (ESR) spectrometer (EMX 300, Bruker) was used. The spectrometer operates at around 9.7 GHz (empty cavity frequency), it was fitted with a multimode high-sensitive cavity (Bruker), and was fully automated. Experimental resonance frequency, which was factored into the calculation for the spectral g value (characteristic splitting factor of a spectrum), was automatically recorded as an operating parameter when the cavity was tuned with the tube-with-sample in place. ESR signal was detected as the first derivative of the resonance absorption by setting the frequency of the magnetic field modulation and that of the signal detection at 100 kHz. In general, the amplitude of modulation (1-5 G) and that of the microwave power (0.5-5.0 mW) were preset to obtain desired signal-to-noise ratio and to keep the detection range below saturation level of the absorption signal. For spectral discrimination, however, modulation amplitude was varied between 1 mG and 20 G, and the microwave power between 1.0 □W and 100 mW, respectively, as needed. First-derivative absorption signal of the reference standard was also recorded at the same time without re-tuning the cavity or altering any operating parameters of the spectrometer. Spectral data as well as the operating parameters are automatically recorded by a dedicated PC, and subsequent calculations or presentations were performed using a WinEPR program (Bruker). Using the known number of free spins in the standard, free-radical concentration (FRC) in the sample was determined. The results are shown in Table 2.
TABLE 2
Free radical data
Sample
FRC (Spins per gram, x E-14)
Antho-G-500 PPM
5.99
Antho-G-250 PPM
17.07
Antho-B-250 PPM
11.68
Antho-B-125 PPM
10.45
Reference (undoped)
11.31
An accelerated aging test was conducted following the standard method described in ASTM2102. UHMWPE without antioxidant (reference), which was gamma irradiated sterilized at 3 MRads in either air (gamma-air) or nitrogen (N2) respectively, were used as references. The aged specimens were analyzed by FTIR and the data are shown in Table 3.
TABLE 3
Oxidation index (OI) of the anthocyanin doped UHMWPE
after two weeks accelerated aging
Max OI
SOI (0-3 mm)
BOI (0.5 mm)
Sample
2 wks
4 wks
2 wks
4 wks
2 wks
4 wks
Antho-G-500 ppm
0.00
0.00
0.00
0.00
0.00
0.00
Antho-G-250 ppm
0.00
0.00
0.00
0.00
0.00
0.00
Antho-B-250 ppm
0.00
0.01
0.00
0.00
0.00
0.00
Antho-B-125 ppm
0.00
0.00
0.00
0.00
0.00
0.00
Reference Gamma
0.56
0.35
0.22
irradiated in Air
Reference Gamma
0.34
0.19
0.30
irradiated in N2
Max OI: maximum oxidation index;
SOI: average surface oxidation index;
BOI: average bulk oxidation index;
2 wks: 2 weeks (ASTM standard);
4 wks: 4 weeks.
The results demonstrate that no oxidation was detected in the anthocyanin doped specimens after two weeks accelerated aging. The oxidation was found through the entire range of specimens of the two references. When the accelerated aging was extended to four weeks, there was still no oxidation detected in the anthocyanin doped sample.
Wear testing was conducted on the acetabular cups with an inner diameter of 32 mm, and a thickness of 5.9 mm. Inserts were manufactured from four anthocyanin doped UHMWPE. All samples were inserted into titanium acetabular shells which are mounted to UHMWPE fixtures using titanium bone screws. Appropriate diameter CoCr femoral heads were mated against the inserts. A multi-station MTS (Eden Prairie, Minn.) hip joint wear simulator was used for testing.
Reference UHMPE materials included: (1) undoped UHMWPE and UHMWPE doped with 500 PPM vitamin E using a powder-liquid blending process. All materials were gamma irradiated at 3 MRads and then annealed at 130° C. for 8 hours. This was done sequentially three times for a total of 9 MRads.
The test specimens were submerged in a lubricant bath for the duration of testing. Alpha Calf Fraction serum was used. After diluted and protein adjusted, the serum solution was 0.2 μm filed before use. The standard method described in ASTM F2025-06 was used for cleaning, weighing and assessing the wear loss of the acetabular inserts. The serum solution was replaced and the inserts weighed every 0.5 million cycles. Testing was conducted for a minimum of 2 million cycles.
Wear rates were determined based on the weight loss of the specimens during testing. The weight loss of the specimens was corrected by fluid absorption that was done by monitoring the weight gain of the static soaked specimens.
TABLE 4 Wear rates of anthocyanin doped UHMWPE after two million cycles on a hip join stimulator Wear rate (mm 3 /mc) Antho-G-500 ppm 1.3 ± 0.1 Antho-G-250 ppm 3.3 ± 1.3 Antho-B-250 ppm 1.4 ± 1.5 Antho-B-125 ppm 2.2 ± 0.6 UHMWPE-vitamin E 6.0 ± 0.4 500 PPM UHMWPE 2.9 ± 0.3 undoped
Table 4 shows the wear rates of the anthocyanin doped UHMWPE after two million cycles on a hip joint stimulator. Lower wear rates were seen in the UHMWPE doped with high concentrations of the anthocyanin (Antho-G 500 PPM and Antho-B 250 PPM). Compared to the 500 PPM vitamin E doped UHMWPE and undoped UHMWPE that were processed and fabricated under the same conditions. The anthocyanin doped UHMWPE had lower wear rates and better wear resistance.
It is well known that antioxidants will react with free radicals during the irradiation-crosslinking process; this reduces the availability of free radicals in UHMWPE for crosslinking. However, the above results demonstrated that the addition of anthocyanin will improve wear resistance of crosslinked UHMWPE. The UHMWPE containing anthocyanin showed a lower wear rate than undoped UHMWPE that received the same irradiation crosslink and heat treatment. All UHMWPE containing anthocyanin showed significant (p<0.011) lower wear than that with 500 ppm vitamin E doped UHMWPE.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
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A method for manufacturing of ultrahigh molecular weight polyethylene (UHMWPE) for implants, where the implants have been machined out of UHMWPE blocks or extruded rods, has anthocyanin dispersely imbedded in the polyethylene. The implant is then exposed to γ ray or electron beam irradiation in an amount of at least 2.5 Mrad followed by a heat treatment to prevent the implant from becoming brittle in the long term as well as to improve strength and wear. The method includes mixing a powder or granulate resin of UHMWPE with an aqueous liquid that contains anthocyanin in a predetermined amount. The water is then evaporated in order to deposit the anthocyanin in a predetermined concentration on the polyethylene particles. The doped UHMWPE particles are compressed into blocks at temperatures in a range of approximately 135° C.-250° C. and pressures in a range of approximately 2-70 MPa. Medical implants are made from the blocks.
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CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent application Ser. No. 11/757,093 (Attorney Docket No. 021629-003910US) filed Jun. 1, 2007, which is a non-provisional of, and claims the benefit of U.S. Provisional Application No. 60/810,522 (Attorney Docket No. 021629-003900US), filed Jun. 2, 2006, the full disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention resides in the field of medical devices and methods and more specifically in the field of vascular catheters and stents that incorporate therapeutic or otherwise bioactive materials.
[0004] 2. Description of the Background Art
[0005] As is well known among clinicians experienced in the treatment of coronary heart disease, the early use of angioplasty for the opening of blood vessels obstructed by stenotic lesions was plagued by frequent restenosis, the tendency of obstructions to re-form during the months following the procedure. Restenosis is thought to be a response of the vascular tissue to the trauma caused by the mechanical action of the devices used in angioplasty, notably angioplasty balloons, pressing against the lesions to forcibly restore vessel patency. The use of stents has since been introduced to address the restenosis problem. While stents have succeeded considerably in reducing the rate of restenosis, they have not eliminated restenosis entirely. Further reduction in restenosis rates has been achieved by the introduction of drug-eluting stents which add a therapeutic effect to the mechanical effect of the stent. The development of drug-eluting stents has extended beyond merely treating restenosis and now provides localized treatment of a variety of conditions in physiological passageways by delivering therapeutic or bio-active agents directly to sites of interest where the agents can produce a range of beneficial physiological effects. Nevertheless, the most prominent use of drug-eluting stents, together with the elimination or reduction of restenosis, is in the treatment of coronary and peripheral artery disease.
[0006] A drug-eluting stent is a stent that contains a bio-active agent applied either to the entire stent surface or to discrete reservoirs or portions of the surface in a manner that causes the stent to release the agent in a continuous and sustained release profile into the physiological environment. Since a wide range of bio-active agents has been disclosed for delivery by stents, the term “drug” is used herein for convenience to represent these agents in general. The drug can be applied to the stent by itself or suspended in a matrix, and the matrix can be either durable or erodible. When the drug is suspended in a matrix, the sustained-release effect is achieved either by allowing the physiological fluid to diffuse into the matrix, dissolve the drug, and diffuse out again with the dissolved drug, or, in the case of erodible matrices, by continuously exposing fresh drug due to the erosion of the matrix, or by a combination of diffusion and erosion. The period of time over which the drug is released by either mechanism is controlled by the chemical properties of the matrix including its solubility or erodibility, the nature and strength of any attraction between the matrix and the drug, and the physical form of the matrix including its porosity and thickness, and the drug loading. Restenosis prevention, and most physiological conditions that are treatable in this manner, respond best to drug administration over a designated but limited period of time. Continued retention of the drug, the matrix, or both beyond this period of time is both unnecessary and potentially detrimental to the surrounding tissue and the health of the subject. The optimal drug-eluting stent for any particular physiological condition is therefore one that fully expels both drug and matrix, and in general all components other than the underlying stent itself, shortly after the desired treatment period which may last from a few hours to several weeks or several months, depending on the condition.
[0007] An additional consideration in the construction and formulation of drug-eluting stents is the integrity of the coating and its ability to remain intact during deployment of the stent. The typical stent is a tubular structure, often with a mesh or lattice-type wall. Stent delivery techniques are well known in the art and in general the tubular structure is maintained in a compressed configuration during insertion into the body, and once it reaches the location of the obstruction, often the site of a stenotic lesion in an artery, the stent is expanded to remove the obstruction. In its compressed configuration, the stent can be guided to and inserted within the obstructed area, and expansion is achieved either by simply releasing the stent from a size-restricting delivery catheter once the desired location is reached, or by allowing the stent to expand by equilibration to the temperature of the surrounding tissues, or by forcibly expanding the stent by mechanical means. A stent that can be expanded by release from a delivery catheter is a resilient stent that is in a stressed state when restricted by the catheter and a relaxed state when released. A stent that is expanded by equilibration to physiological temperature is one that is made of a shape-memory alloy such as Nitinol. Both types are self-expanding stents. For stents that are expanded only by the application of a force from within the stent interior, the force is typically created by a balloon similar to angioplasty balloons, and the stent is mounted to the balloon in a contracted or “crimped” configuration. In all of these different means of expansion, the stent undergoes a physical deformation and stress during expansion due to bending, changes in curvature, and changes in the angles of stent structural features. The stresses imposed on the coating during these transformations render the coating susceptible to breakage, separation from the stent, or both. Also, in some delivery systems, the stent is placed on the tip of a long catheter and is uncovered and exposed during insertion. As the catheter enters the curved and branched sections of the vascular system, the exposed stent contacts the walls of the blood vessels, which may have hard and rough calcified regions, as well as narrow lesions. Such contact can damage, separate, or remove the coating from the stent. Stent coatings can also be damaged by interactions with components of the delivery catheter.
[0008] Coating integrity and strong adhesion to the stent have been achieved in the prior art by the use of a primer layer applied to the stent surface prior to formation of the matrix-supported drug coating. The primer is typically a polymer other than the polymer used as the drug matrix, and a commonly used primer material is parylene (dichloro-p-xylene) in its various forms (i.e., parylene C, N, or HT, or combinations), applied to the stent by vapor deposition. To be effective, the primer layer is generally comparable in thickness to the drug-matrix coating, or within the same order of magnitude, but the primer is typically not biodegradable or erodible, or is substantially less so than the polymeric matrix supporting the drug. The primer thus remains on the stent surface long after the drug and matrix have left the stent. No longer serving a useful function, the residual primer presents a risk of producing an undesirable physiological response in the contacting tissue.
[0009] It is therefore desirable to provide stents with a therapeutic agent wherein the stent may be used to deliver the therapeutic agent to a treatment site over a controlled period of time. It is further desired that once the drug has eluted into the treatment site that only the bare metal stent surface remains, or an ultra thin layer of material that does not produce any adverse biocompatibility issues at the treatment site. It is also desirable to provide methods for coupling the therapeutic agent with the stent so that the therapeutic agent remains coupled to the stent during delivery and expansion of the stent.
BRIEF SUMMARY OF THE INVENTION
[0010] It has now been discovered that a drug, preferably one that is matrix-supported, can be deposited on a metallic stent surface without the need for primers of the prior art, or for a primer in general, while still producing a coating that will retain its integrity as the stent is delivered and deployed. This is achieved by first exposing the stent surface to a gaseous species in the presence of a gaseous plasma that will cause the species to polymerize on the surface of the stent and enhance adhesion of the drug coating. While not intending to be bound by any particular theory, it is believed that the plasma-deposited polymer may enhance drug adhesion by either interacting with (i.e., bonding to, grafting to, or adhering to by some other mechanism) the overlying drug, the matrix in the case of a matrix-supported drug, or the underlying stent, by forming an ultra-thin tie layer. The ultra-thin tie layer preferably ranges in thickness from about 100 Å to about 5,000 Å, more preferably from about 100 Å to about 1,000 Å and even more preferably from about 100 Å to 500 Å. In some cases, the tie layer may be a single molecule in thickness, while in other cases the layer may be several molecules in thickness, depending on the type and degree of polymerization. In one aspect of the invention, the tie layer formed by the plasma-deposited polymer on the stent surface is about 500 Å or less in thickness. The drug is then applied, either by itself or as a mixture with a second polymeric material, to the plasma-deposited polymer by conventional techniques other than plasma deposition to achieve a combined coating having a thickness in the micron or mil (thousandths of an inch) range. The ratio of therapeutic agent to polymer in the matrix can vary widely. In preferred embodiments, the percentage by weight of therapeutic agent in the polymer matrix ranges from about 0.1% to 50%, preferably from about 0.1% to about 10% and more preferably from about 0.1% to about 1%. Additionally, the thickness of the polymer matrix often ranges from about 0.2 μm up to about 5 μm.
[0011] In embodiments in which a second polymer is included as a matrix for the drug, the second polymer can be either durable (i.e., non-erodible) or bioerodible. Optimal polymers for use as the second polymer and the plasma-deposited polymer will be those that are sufficiently compatible to permit diffusion of the second polymer into the plasma deposited polymer, and possibly to permit bonding of the two layers creating an interpenetrating polymer network. This interpenetrating network does not need to be complete, several molecular layers would be sufficient to establish excellent bonding of the two different layers. The plasma intensity used in forming the initial plasma-deposited polymeric layer will be great enough to cause the polymerizing species to form a flexible and resilient polymer anchor coating yet not so great as to cause crosslinking of the polymer to a degree that renders the initial layer brittle in relation to the expandable stent. While not bound by any theory the judicious selection of plasma parameters can control the plasma polymer's apparent molecular weight (chain extension), crosslink density, swell, modulus and other essential properties such that the plasma deposited layer may act as a modulus gradient or even modulus trough between that of the metal and the drug infused layer thereby reducing the stress on the drug infused layer. Once the second polymer and drug are deposited, the resulting final coating on the stent surface is sufficiently elastic and flexible to withstand the stresses imposed during the deployment of the stent, notably the expansion, stretching, and bending cited above, without producing excessive cracks in the coating or causing the coating to separate from the stent itself. In preferred embodiments, the final coating is sufficiently porous or absorptive of physiological fluid to admit the fluid into the coating where the fluid can dissolve the drug and diffuse outward with the dissolved drug, or in the case of erodible matrices, where the fluid can promote the erosion of the coating. In this manner, the drug is released to the physiological environment in a controlled and sustained manner so as to have its desired therapeutic or bio-active effect. Preferably, the plasma intensity in the initial deposition will also be sufficiently limited to allow the plasma-deposited polymer to swell upon contact with the coating solution of the drug and second polymer to thereby enhance the degree of diffusion of the coating solution into the plasma-deposited polymer, and thereby form an interpenetrating network. As in the prior art, the polymer applied in combination with the drug in the second stage of the deposition erodes in the physiological environment over prolonged exposure to the physiological tissue or fluid. Thus, typically the drug polymer matrix completely erodes away leaving behind an ultra thin plasma polymerized tie layer or anchor coating on the stent. It is more preferable however, if the entire finished coating, including the drug polymer matrix and plasma-deposited polymer, erodes in this manner. Thus, after an extended period of time, the drug and, in the case of bioerodible matrices, the matrix will have been released from the stent, and the stent will contain no polymer at all or at most an extremely thin layer of the plasma-deposited coating, i.e., a substantially monomolecular layer or a layer at most about 500 Å in thickness, with no other residual material. Upon release of the entire drug and erosion of the matrix polymer, an uncoated, or essentially uncoated, stent surface will remain, so that the body fluids and tissues are exposed only to the material of the stent itself. In the case of a durable matrix rather one that is bioerodible, an advantage of the present invention is its elimination of the need for parylene as a primer coating. This advantage is of value in situations where the use of parylene is undesirable.
[0012] In preferred embodiments, the invention resides in a stent with a plasma-polymer treated surface, a bioerodible matrix deposited on the plasma-treated surface, and a drug suspended in the matrix. As noted above, the stent is preferably one in which, if any material remains on the stent surface upon full release of the drug, such residual material is at most about 500 Å in thickness. This invention also resides in methods of use, including a method of treating restenosis, of drug delivery, or both, by implanting a stent with a drug coating that leaves at most about 500 Å of residual material on the stent surface after all drug has been released, or a stent in which the stent surface is free of substantially all material typically within 24 months, preferably within 12 months and more preferably within 3-9 months of deployment.
[0013] In a first aspect of the present invention a method manufacturing an intraluminal device bearing a therapeutic agent releasable from the device in a time-controlled manner comprises exposing a metallic substrate to a gaseous plasma form of a substance that polymerizes in the plasma form under conditions causing the substance to form a polymer anchor coating of about 500 Å in thickness or less on the substrate. A layer containing the therapeutic agent may then be deposited over the polymer anchor coating. All of the therapeutic agent is substantially releasable into a physiological environment gradually over a period ranging from about one hour up to about six months.
[0014] In another aspect of the present invention, a method for manufacturing an intraluminal device bearing a therapeutic agent releasable from the device in a time-controlled manner comprises exposing a metallic substrate to a gaseous plasma form of a substance that polymerizes in the plasma form under conditions causing the substance to form a polymer anchor coating on the substrate. A layer containing the therapeutic agent is then deposited over the anchor coating. The therapeutic agent may be in a polymer matrix that releases substantially all of the therapeutic agent into a physiological environment gradually over a period ranging from about one hour up to about six months and following release of the therapeutic agent, any polymer remaining on the substrate is about 500 Å or less in thickness.
[0015] In still another aspect of the present invention, a stent for placement in a body lumen comprises a plurality of struts coupled together forming a substantially tubular structure. The plurality of struts have a polymer anchor coating of about 500 Å in thickness or less disposed thereon and a layer containing a therapeutic agent is positioned over the polymer anchor coating. The polymer anchor coating is formed from a gaseous plasma form of a substance that polymerizes on the struts while in the plasma form, and substantially all of the therapeutic agent releases into a physiological environment gradually over a period ranging from about one hour up to about six months. Sometimes the tubular structure is self-expanding and other times it may be expanded with a balloon. Often the struts are a metal, such as a material like stainless steel, nickel-titanium alloy or cobalt-chromium alloy. The struts may also be a polymer and can be at least partially bioerodible.
[0016] In another aspect of the present invention, a method for delivering a therapeutic agent to a target treatment site comprises introducing a delivery catheter having a stent disposed thereon to the target treatment site and deploying the stent into the target treatment site. The stent comprises a plurality of struts having a polymer anchor coating of about 500 Å in thickness or less disposed thereon and a layer containing the therapeutic agent is positioned over the polymer anchor coating. The polymer anchor coating is formed from a gaseous plasma form of a substance that polymerizes on the struts while in the plasma form and substantially all of the therapeutic agent is released into the target treatment site gradually over a period ranging from about one hour up to about 6 months. Often deploying the stent comprises radially expanding the stent into a coronary or peripheral artery where the therapeutic agent inhibits restenosis.
[0017] Usually, the polymer anchor coating can withstand significant cracking during expansion and the coating also remains coupled to the intraluminal device without substantially separating from the device during its expansion. Sometimes the polymer anchor coating is continuous over substantially all of a surface of the metallic substrate or stent struts, which may be a material selected from the group consisting of stainless steel, nickel-titanium alloys and cobalt-chromium alloys.
[0018] Sometimes the polymer anchor swells when the therapeutic agent is deposited over the polymer anchor and this enhances diffusion of the therapeutic agent into the polymer coating. Often, the substance used to form the polymer anchor is either in gaseous form under ambient conditions or the substance can be volatized. Common materials that may be used for the polymer anchor include but are not limited to materials selected from the group consisting of allyl substituted compounds, acrylic acids, methacrylic acids, acrylates, methacrylates, ethylene glycol, organosilicones, thiophenes, vinyl benzene, vinyl pyrrolidinone and methane.
[0019] The substrate may be cleaned prior to plasma polymerization. Plasma processes using non-polymerizable (carbonless) gases such as nitrogen, argon, oxygen, hydrogen, nitrous oxide and many others are very effective in providing atomic level cleanliness and may be incorporated typically as a first step in a multi-step plasma polymerization process. An inert noble gas may also be used during the step of exposing the metallic substrate in order to provide a diluent in the presence of the substance to be polymerized. Masking can be used to cover a portion of the substrate so as to selectively apply the polymer anchor coating to the substrate. The degree of polymerization and cross-linking of the polymer anchor may also be controlled by adjusting operating parameters such as power level and exposure time as well as by applying power in a pulsewise manner. Pulse may be controlled by adjusting pulse frequency, duty cycle and power.
[0020] The therapeutic agent may be deposited on to the polymer anchor coating by a number of methods such as dipping, spraying, brush coating, syringe deposition, chemical vapor deposition or plasma deposition. Often, the intraluminal devices or stents are loaded onto a mandrel and rotated during deposition.
[0021] Often the therapeutic agent inhibits restenosis. The therapeutic agent may also be at least one of antibiotics, thrombolytics, anti-platelet agents, anti-inflammatories, cytotoxic agents, anti-proliferative agents, vasodilators, gene therapy agents, radioactive agents, immunosuppressants, chemotherapeutics, endothelial cell attractors, endothelial cell promoters, stem cells, hormones, smooth muscle relaxants, mTOR inhibitors and combinations thereof. Often, the therapeutic agent dissolves in a physiological fluid such as blood or cytoplasm.
[0022] Sometimes the therapeutic agent is dispersed in a polymeric matrix that is positioned over the polymer anchor coating. Often, the polymeric matrix will diffuse into the polymer anchor coating or bond thereto. In some embodiments, the porosity of the polymer anchor coating may be varied in order to control blending of the polymer matrix with the polymer anchor coating thereby controlling release rate of the therapeutic agent from the polymer matrix. The polymeric matrix may comprise a first polymer layer disposed over the therapeutic agent with an optional second therapeutic agent disposed over the first polymer layer. A second polymer layer may then be placed over the second therapeutic agent. The first and second polymer layers may be adapted to control release rate of the therapeutic agent from the polymer matrix. Often, the polymeric matrix is a different polymer than the polymer anchor coating. Usually, the polymeric matrix biodegrades from the polymer anchor coating over a period not exceeding twenty-four months. The polymeric matrix is usually sufficiently porous or absorptive of a physiological fluid such as blood or cytoplasm to admit the physiological fluid into the polymeric matrix thereby dissolving the therapeutic agent or promoting bioerosion of the polymer matrix.
[0023] Possible materials used in the polymer matrix include a material selected from the group consisting of polyhydroxyalkanoates, polyalphahydroxy acids, polysaccharides, proteins, hydrogels, lignin, shellac, natural rubber, polyanhydrides, polyamide esters, polyvinyl esters, polyvinyl alcohols, polyalkylene esters, polyethylene oxide, polyvinylpyrrolidone, polyethylene maleic anhydride, acrylates, cyanoacrylates, methacrylates and poly(glycerol-sebacate).
[0024] These and other embodiments are described in further detail in the following description related to the appended drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A is a planar view of a stent unrolled and flattened out.
[0026] FIG. 1B is a perspective view of the stent illustrated in FIG. 1A .
[0027] FIG. 1C is a planar view of the stent illustrated in FIG. 1A after it has been radially expanded.
[0028] FIG. 2 shows a plasma chamber where a plasma polymerized tie layer may be applied to a stent.
[0029] FIG. 3A shows a schematic diagram of a spray system for applying a therapeutic agent in a polymer matrix to a stent.
[0030] FIGS. 3B-3C illustrate exemplary embodiments of a fixture used to hold stents during the spraying process of FIG. 3A .
[0031] FIG. 4 illustrates a cross-section of a stent strut having a drug-polymer matrix deposited over a plasma polymerized tie layer that has been applied to the stent surface.
[0032] FIGS. 5A-5B illustrate delivery and deployment of a drug coated stent at the target treatment site.
[0033] FIG. 6A illustrates a strut of the stent shown in FIGS. 1A-1B .
[0034] FIG. 6B illustrates a strut of the stent shown in FIG. 6A after it has been expanded.
[0035] FIG. 6C illustrates a strut of the stent shown in FIG. 6A after it has been expanded.
DETAILED DESCRIPTION OF THE INVENTION
[0036] The present invention is of primary interest in connection with medical devices such as stents fabricated from metals and metal alloys. Any of the wide range of metals and alloys known in the art can be used. Examples are the platinum, iridium, titanium, nickel, silver, gold, tantalum, tungsten, alloys of any of the above, Nitinols (a class of shape-memory alloy in which approximately equal proportions of nickel and titanium are the primary constituents), Inconel® (a class of high-strength austenitic nickel-chromium-iron alloys), 300 series stainless steels, magnesium, cobalt, chromium, and cobalt-chromium alloys such as MP35N® (ASTM F562, SPS Technologies, Inc., an alloy of cobalt, chromium, nickel, and molybdenum). The invention also has applicability to stents fabricated from non-metals including both durable and bioerodible polymers or any material for which enhanced adherence characteristics could be beneficial.
[0037] A preferred embodiment of a stent is illustrated in FIGS. 1A-1C . In FIG. 1A a portion of stent segment 32 is shown in a planar shape for clarity. Stent segment 32 comprises parallel rows 122 A, 122 B and 122 C of I-shaped cells 124 formed into a cylindrical shape around axial axis A. FIG. 1B shows the stent of FIG. 1A in perspective view. Referring back to FIG. 1A , cells 124 have upper and lower axial slots 126 and a connecting circumferential slot 128 . Upper and lower slots 126 are bounded by upper axial struts 132 , lower axial struts 130 , curved outer ends 134 , and curved inner ends 136 . Circumferential slots 128 are bounded by outer circumferential strut 138 and inner circumferential strut 140 . Each I-shaped cell 124 is connected to the adjacent I-shaped cell 124 in the same row 122 by a circumferential connecting strut 142 . Row 122 A is connected to row 122 B by the merger or joining of curved inner ends 136 of at least one of upper and lower slots 126 in each cell 124 .
[0038] In FIGS. 1A and 1B , the stent includes a bulge 144 in upper and lower axial struts 130 , 132 extending circumferentially outwardly from axial slots 126 . These give axial slots 126 an arrowhead or cross shape at their inner and outer ends. The bulge 144 in each upper axial strut 130 extends toward the bulge 144 in a lower axial strut 132 in the same cell 124 or in an adjacent cell 124 , thus creating a concave abutment 146 in the space between each axial slot 126 . Concave abutments 146 are configured to receive and engage curved outer ends 134 of cells 124 in the adjacent stent segment, thereby allowing interleaving of adjacent stent segment ends while maintaining spacing between the stent segments. The axial location of bulges 144 along upper and lower axial struts 130 , 132 may be selected to provide the desired degree of inter-segment spacing.
[0039] FIG. 1C shows stent 32 of FIGS. 1A-1B in an expanded condition, again, unrolled and flattened out for clarity. It may be seen that axial slots 124 are deformed into a circumferentially widened modified diamond shape with bulges 144 on the now diagonal upper and lower axial struts 130 , 132 . Circumferential slots 128 are generally the same size and shape as in the unexpanded configuration. Bulges 144 have been pulled away from each other to some extent, but still provide a concave abutment 146 to maintain a minimum degree of spacing between adjacent stent segments. As in the earlier embodiment, some axial shortening of each segment occurs upon expansion and stent geometry can be optimized to provide the ideal intersegment spacing.
[0040] It should also be noted that the embodiment of FIGS. 1A-1C also enables access to vessel side branches blocked by stent segment 32 . Should such side branch access be desired, a dilatation catheter may be inserted into circumferential slot 128 and expanded to provide an enlarged opening through which a side branch may be entered.
[0041] A number of other stent geometries are applicable and have been reported in the scientific and patent literature. Other stent geometries include, but are not limited to those disclosed in the following U.S. patents, the full disclosures of which are incorporated herein by reference: U.S. Pat. Nos. 6,315,794; 5,980,552; 5,836,964; 5,527,354; 5,421,955; 4,886,062; and 4,776,337.
[0042] Other stents to which the coatings and process of the present invention can be applied are widely disclosed in other publications. In addition to those listed above are the disclosures in U.S. Patent Application Publications Nos. U.S. 2004/0098081 A1 (Landreville, S., et al., published May 20, 2004), US 2005/0149159 A1 (Andreas, B., et al., published Jul. 7, 2005), U.S. 2004/0093061 A1 (Acosta, P., et al., published May 13, 2004), U.S. 2005/0010276 A1 (Acosta, P., et al., published Jan. 13, 2005), U.S. 2005/0038505 A1 (Shulze, J. E., et al., published Feb. 17, 2005), U.S. 2004/0186551 A1 (Kao, S., et al., published Sep. 23, 2004), and U.S. 2003/0135266 A1 (Chew, S., published Jul. 17, 2003). Further disclosures are found in unpublished co-pending U.S. patent application Ser. No. 11/148,713, filed Jun. 8, 2005, entitled “Devices and Methods for Operating and Controlling Interventional Apparatus” (Attorney Docket No. 14592.4002); and Ser. No. 11/148,545, filed Jun. 8, 2005, entitled “Apparatus and Methods for Deployment of Multiple Custom-Length Prosthesis” (Attorney Docket No. 14592.4005). The full disclosures of each of these documents are incorporated herein by reference.
[0043] Therapeutic agents, frequently in a polymer matrix, may be deposited onto a stent such as the embodiment illustrated in FIGS. 1A-1B for localized drug delivery. Often, a tie layer is deposited onto the stent first and then the therapeutic agent is deposited onto the tie layer. The tie layer facilitates adhesion between the therapeutic agent and the stent. While various polymers may be used as the tie layer, in the present invention any species that will polymerize in a plasma environment can be deposited in a plasma deposition step onto a stent. Thus plasma polymerization, also known as plasma enhanced chemical vapor deposition (PECVD), may be used to polymerize the tie layer onto a stent surface. This process is distinguished from plasma activation wherein a non-polymerizable gas such as argon, oxygen or nitrogen is used to burn off organic materials from the stent surface and/or leave a highly energized and therefore reactive surface.
[0044] As noted above, the selection of the species for plasma polymerization is preferably also coordinated with the selection of the matrix polymer, i.e., the polymeric material deposited in the second step and serving as the carrier for the drug, to achieve compatibility between the two polymers. Alternatively, a mixture of species can be used, where one component of the mixture is compatible with the matrix polymer. The species or mixture to be plasma polymerized will be one that is either in gaseous form under ambient conditions or one that can be readily volatilized. Examples of species that meet this description that may be suitable include but are not limited to unsaturated species such as allyl substituted compounds like allyl alcohol, allyl amine, N-allylmethylamine, allyl chloride, allyl bromide, allyl iodide, allyl acetate, allyl chloroformate, allyl cyanide, allyl cyanoacetate, allyl methyl ether, allyl ethyl ether, allyl propyl ether, allyl isothiocyanate, allyl methacrylate, N-allylurea, N-allylthiourea and allyl trifluoroacetate. Other species that may potentially be used for plasma polymerization include acrylic acid, methacrylic acid, acrylate, methacrylates like 2-hydroxyethylmethacrylate and methacrylate esters. Still other possible species include ethylene glycol, perfluoroalkanes like perfluorocyclohexane, perfluoromethylcyclohexane, perfluoro-1,2-dimethylcyclohexane, perfluoro-1,3-dimethylcyclohexane and perfluoro-1,3,5-trimethylcyclohexane. Yet other species that may potentially be used for plasma polymerization of the tie layer include organosilicones such as trimethylsilane, vinyl trimethylsilane, hexamethyldisiloxane, hexamethyldisilazane. Still other species may include thiophenes, vinyl benzene, and vinyl pyrrolidinone. Further possible examples are saturated species that will fragment in the plasma environment to become free radicals that will readily polymerize. The simplest example is methane; another is perfluoropropane.
[0045] The polymer deposited by the plasma process can be continuous over the stent surface or discontinuous, and it can be one that displays engineering properties such as tensile strength and elasticity, or one that does not. The degree of polymerization can vary as well, from polymers that are oligomeric in nature to those of relatively high molecular weight. The plasma-induced polymerization and deposition are achieved by placing the bare stent in contact with the species in gaseous form, preferably in the presence of an inert diluent gas, and imposing high-energy radiation, such as radiofrequency or ultraviolet radiation, sufficient to ionize the species, and the diluent gas when present, to a plasma state. Examples of inert gases that can be used as the diluent gas are argon, helium, and neon. When a diluent is used, the relative amounts of polymerizable species and diluent can vary widely, with species:diluent volumetric ratios preferably ranging from about 10:90 to about 90:10, and most preferably from about 20:80 to about 50:50. The exposure of the stent to the plasma is preferably performed at a reduced pressure in a vacuum chamber, preferably at a pressure of from about 50 mTorr (6.6 Pa) to about 250 mTorr (33 Pa), and most preferably from about 80 mTorr (10.6 Pa) to about 230 mTorr (31 Pa).
[0046] Control of the intensity of the plasma treatment to a level that will produce the desired degree of polymerization without excessive crosslinking and thus without depositing a rigid polymer layer on the stent surface can be achieved by limiting the power level, limiting the exposure time, applying the power in a pulsewise manner, controlling gas flow rates or combinations thereof. Pulse may be controlled by adjusting pulse frequency, duty cycle and power. Optimal values of plasma parameters will vary with the chamber size and configuration as well as the electrode design and vacuum pump capacity and conductance. None of these variations are critical to the present invention. In experiments conducted with a Plasma Science PS0500 system having a chamber volume of approximately 5 cubic feet and a plasma work zone of about 2.5 cubic feet, best results were generally achieved with a power level within the range of about 25 Watts to about 1000 Watts, and preferably within the range of about 25 Watts to about 500 Watts. Preferred pressures were generally in the range from about 35 mTorr to about 200 mTorr. Exposure times within the range of about 30 seconds to about 30 minutes, and preferably about 1 minute to about 10 minutes, will likewise produce the best results in most cases. The flow rate of the plasma gas across the stent surface can likewise vary, typically from about 10 to about 1,000 cubic centimeters per minute (measured under, or corrected to, standard temperature and pressure and expressed as sccm), and preferably from about 20 sccm to about 100 sccm. The treatment does not require elevated temperature and is readily performed at temperatures less than 50° C., preferably from about 20° C. to about 40° C. One of ordinary skill in the art will appreciate that temperatures may exceed 50° C. and other operating parameters may exceed the ranges described herein depending on the specific monomers being employed.
[0047] As noted above, the thickness of the plasma-deposited polymer need only be great enough to allow the second (matrix) polymer and drug to diffuse into the plasma-deposited polymer during the deposition of the drug and second polymer. Upon contact with a liquid application solution of the second polymer and drug in a carrier solvent, the plasma-deposited polymer may swell to receive the carrier solvent or it may be sufficiently porous independently of any swelling to permit the solvent, second polymer, and drug to diffuse into it. With either mechanism, the plasma-deposited polymer layer will be applied under conditions that result in a coating with a thickness of about 500 Å or less, preferably from about 100 Å to about 500 Å, and most preferably from about 100 Å to about 300 Å, prior to the application of the second polymer and drug. Optionally, the plasma-deposited coating can contain functional groups by which the coating can adhere to second polymer, either by covalent bonds, ionic or Van der Waals attraction or by polar covalent bonding, to further enhance the adhesion of the drug-delivery coating to the stent surface.
[0048] The plasma-induced polymerization and deposition can be preceded by cleaning of the stent surface, which can be performed using plasma activation methods. A preliminary plasma treatment can thus be used for sterilization of the stent surface and for removal of contaminants by, for example, etching away weakly bonded molecules. Preliminary plasma treatments can also be used to alter the surface topography of the stent. Examples of gases suitable for these preliminary plasma treatments are molecular oxygen and low molecular weight solvents, such as fluorinated hydrocarbons or carbon tetrafluoride.
[0049] FIG. 2 illustrates a plasma chamber 202 where the plasma polymerized tie layer may be deposited on a stent surface. A plurality of stents 210 are mounted on a mandrel 212 that may rotate 214 , although the plasma generally will uniformly contact all surfaces of the stent unless they are masked. Masking of the stent surface using methods well known in the art may be employed to control where the plasma polymerized material is deposited on the stent. The species to be plasma polymerized may be a gas introduced directly into plasma chamber 202 or it may be volatilized 204 and then introduced into the plasma chamber 202 . A controller 208 may be used to control the various operating parameter such as power, pulse frequency and exposure time. The process does not typically require elevated temperature and may be conducted at temperatures less than 50° C., preferably from about 20° C. to about 40° C. Additionally, a diluent gas 206 , typically a noble gas may also be used during the process.
[0050] The second polymer used in the practice of this invention, i.e., the polymer that serves as the primary matrix for the retention and prolonged release of the drug, can be any of the biocompatible and bioerodible polymers known in the art and disclosed in the literature for this use. The terms “erodible” and “bioerodible” are used herein interchangeably to include breakdown of the polymer layer by decomposition, dissolution, or physical separation in the form of fissures and fragmentation, or combinations of these effects. Suitable polymers are those that, once the stent is implanted, will fully dissociate from the stent due to any of these processes over a period of about 2 weeks to about 24 months, preferably from about 2 weeks to about 12 months, and more preferably from about 1 month to about 3 to 9 months. Certain polymers that meet this description are disclosed in Shulze, J. E., et al., U.S. Pat. No. 6,939,376, issued Sep. 6, 2005, and incorporated herein by reference.
[0051] Some examples of other biodegradable materials include polyesters such as polyhydroxyalkanoates (PHA) and polyalphahydroxy acids (AHA). Exemplary PHAs include, but are not limited to polymers of 3-hydroxypropionate, 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxycaproate, 3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynonanoate, 3-hydroxydecanoate, 3-hydroxyundecanoate, 3-hydroxydodecanoate, 4-hydroxybutyrate and 5-hydroxyvalerate. Examples of AHAs include, but are not limited to various forms of polylactide or polylactic acid including poly(d-lactic acid), poly(1-lactic acid), poly(d,l-lactic acid), polyglycolic acid and polyglycolide, poly(lactic-co-glycolic acid), poly(lactide-co-glycolide), poly(ε-caprolactone) and polydioxanone. Polysaccharides including starch, glycogen, cellulose and chitin may also be used as a biodegradable material. It is also feasible that proteins such as zein, resilin, collagen, gelatin, casein, silk or wool could be used as a biodegradable implant material. Still other materials such as hydrogels including poly(hydroxyethyl methylacrylate), polyethylene glycol, poly(N-isopropylacrylamide), poly(N-vinyl-2-pyrrolidone), cellulose polyvinyl alcohol, silicone hydrogels, polyacrylamides, and polyacrylic acid are potential biodegradable implant materials. Other potential biodegradable materials include lignin, shellac, natural rubber, polyanhydrides, polyamide esters, polyvinyl esters, poly(ethylene vinyl alcohol), polyvinyl alcohol, polyalkylene esters, polyethylene oxide, polyvinylpyrrolidone, polyethylene maleic anhydride and poly(glycerol-sebacate). Other potential materials suitable for the drug matrix may include polycarbonates, polyamides, polyanhydrides, polyamino acids, polyortho esters, polyacetals, degradable polycyanoacrylates, and degradable polyurethanes. Presently preferred are poly(d,l-lactic acid) as the matrix polymer and a polymer obtained by plasma deposition of allyl amine as the plasma-deposited polymer.
[0052] The drug can be any of the wide variety of bio-active agents disclosed in the literature for use with stents. Included among these agents are anti-restenosis, anti-proliferative, immunosuppressive, antibiotic, thrombolytic, cytotoxic, and cystostatic agents, as well as growth factors and DNA. Examples of antiproliferative substances are actinomycin D and its derivatives and analogs, angiopeptin, and angiotensin-converting enzyme inhibitors such as captopril, cilazapril and lisinopril. Further examples are calcium channel blockers such as nifedipine and colchicine, fibroblast growth factor (FGF) antagonists, fish oil (omega 3-fatty acid), histamine antagonists, lovastatin, monoclonal antibodies specific for Platelet-Derived Growth Factor (PDGF) receptors, nitroprusside, phosphodiesterase inhibitors, prostaglandin inhibitors, suramin, serotonin blockers, steroids, thioprotease inhibitors, triazolopyrimidine, and smooth muscle relaxants such as nitric oxide. Examples of antineoplastics and/or antimitotics are paclitaxel, docetaxel, methotrexate, azathioprine, vincristine, vinblastine, fluorouracil, doxorubicin hydrochloride, and mitomycin. Examples of antiplatelets, anticoagulants, antifibrins, and antithrombins are sodium heparin, low molecular weight heparins, heparinoids, hirudin, argatroban, forskolin, vapiprost, prostacyclin and prostacyclin analogues, dextran, D-phe-pro-arg-chloromethylketone (synthetic antithrombin), dipyridamole, glycoprotein IIb/IIa platelet membrane receptor antagonist antibody, recombinant hirudin, and thrombin inhibitors such as ANGIOMAX® (Biogen, Inc., Cambridge, Mass., USA). An example of an antiallergic agent is permirolast potassium. A class of particularly preferred therapeutic agents are mTOR inhibitors of which prime examples are rapamycin and its derivatives such as BIOLIMUS A9®, (Biosensors International, Singapore), everolimus, or ABT 578 (Abbott Laboratories, Abbott Park, Ill., USA). Further derivatives of rapamycin that can be used for this purpose are disclosed in Betts, R. E., et al., U.S. Patent Application Publication No. 2005/0131008 A1, published Jun. 16, 2005, the entire contents of which are incorporated herein by reference.
[0053] The ratio of therapeutic agent to polymer in the therapeutic agent/matrix application step can vary widely. In some embodiments, this ratio can be as high as 110% therapeutic agent to polymer matrix, while in preferred embodiments, the percentage by weight of therapeutic agent in the polymer matrix ranges from about 0.1% to 50%, preferably from about 0.1% to about 10% and more preferably from about 0.1% to about 1%.
[0054] Application of the combination of matrix polymer and drug to the plasma-deposited polymer anchor layer on the stent can be achieved by various methods, some of which are described in the literature for stents bearing therapeutic agents. A preferred method is to form a solution or suspension of the drug and polymer in a volatile liquid solvent or liquid suspending medium, apply the solution or suspension to the stent surface, and then evaporate the solvent or suspending medium. Application can be achieved by dipping, spraying, brush coating, or any equivalent method. A description of spray application is found in Shulze, J. E., et al., U.S. Pat. No. 6,939,376 B2, incorporated herein by reference. Any solvent or suspending medium that will not affect the molecular structure or physical state of the plasma-deposited polymer can be used. Examples of suitable solvents and suspending media are acetone, dichloromethane, and diethyl ether.
[0055] In a presently preferred method of application, stents are loaded on a mandrel which can have a circular cross section or a cross section of triangular or other polygonal shape. The mandrel has raised features that engage the inner surface of the stent at discrete locations. These features allow the stent to rotate with the mandrel and also to be removed following the spray operation without damage to the coating. The mandrel is held in a rotary fixture coupled to a computer-controlled rotary stepper motor capable of rotating the mandrel about its longitudinal axis. The motor or mandrel may be mounted on a linear positioning table capable of moving the stent relative to the spray nozzle along at least one horizontal axis.
[0056] A mixture of the drug, polymer, and solvent is sprayed onto the mandrel-mounted stents by a spray nozzle mounted on an X-Y-Z positioning system driven by a computer-controlled linear actuator. A pump module supplying the nozzle is connected to a reservoir of solvent and to a reservoir containing the mixture of drug, polymer, and solvent. The system is pressurized with solvent from the solvent reservoir to prevent leaking of the fluid lines and of the reservoir containing the mixture of drug, polymer, and solvent. Preferably, major quantities of the mixture of drug, polymer and solvent are applied to the stent struts at the surfaces of the struts that face radially outward, while a lesser quantity (to produce a coating of lesser thickness) is applied to circumferentially-facing surfaces and to axially-facing sidewalls, and little or no material to surfaces that face radially inward. Much of the solvent in the mixture vaporizes during spraying. Following spraying, the stents are removed from the mandrel and placed in a controlled environment for sufficient time to allow any residual solvent to evaporate. The controlled environment allows operating parameters such as temperature, pressure and gas environment to be regulated. Multiple passes of the spray nozzle over each stent are made until the desired weight or thickness of coating has been applied. Other aspects of suitable stent spraying processes are described in co-pending U.S. patent application Ser. No. 11/099,418, filed Apr. 4, 2005, “Topographic Coatings and Coating Methods for Medical Devices” (Attorney Docket No. 021629-002610US), the contents of which are incorporated herein by reference.
[0057] FIG. 3A shows a schematic diagram of a system 300 for coating a stent with a therapeutic agent. Coating system 300 includes a controller 302 that allows all process parameters of the system 300 to be pre-programmed or manually selected, including controlling temperatures, pressures, positions, etc. A reservoir 306 holds the therapeutic agent and a polymer, such as Biolimus A9™ and PLA, dissolved in a solvent such as acetone. Chiller 304 allows the temperature of reservoir 306 to be controlled so as to prevent degradation of the therapeutic agent or excessive solvent evaporation. A pump 312 , such as an IVEK pump, pumps the fluid containing the therapeutic agent and polymer through piping 308 to the spray nozzle 318 , such as a Sono-Tek Micromist nozzle, where it can be deposited over a stent surface, 322 . A second reservoir 310 may also contain acetone or another solvent to help clean and purge the system as needed. Inert gas 314 such as nitrogen may also be used to pressurize the system 300 thereby directing the fluid to the stent. A broadband generator 316 is also used in the system in order to volatilize the therapeutic agent and polymer to facilitate spraying it on the stent 322 . The spray nozzle 318 may also be coupled to an XYZ positioning system so as to allow precise movement of the nozzle 318 with respect to the stent 322 . In spray system 300 , a single stent 322 is shown mounted to a rotating mandrel 324 . Multiple stents may be loaded onto the mandrel and a positioning system may also be used to move the stent with respect to the spray nozzle 318 . This way, a uniform coating of therapeutic agent and polymer matrix may be applied to the stent surface.
[0058] One will of course appreciate that many other fixtures may be used to hold and position stents during the spraying process. For example, in FIG. 3B , fixture 350 accommodates multiple stents 352 on each rotating mandrel 354 and a plurality of mandrels are circumferentially disposed around a rotating drum 356 , thereby increasing the stent processing capacity. Another exemplary embodiment of a spray fixture is seen in the perspective view of FIG. 3C . In FIG. 3C , multiple stents 376 are mounted on rotating mandrels 378 , arranged in a step-wise fashion in the fixture.
[0059] FIG. 4 shows a cross section of a stent strut 402 after the plasma polymerized tie layer and drug-polymer matrix have been applied. A plasma polymerized, ultra thin, monomolecular tie layer 404 is first applied to the stent surfaces as described above. The tie layer 404 is fairly uniform thickness on all stent surfaces. The polymer matrix 406 is then coated over the tie layer 404 . The polymer matrix contains a drug 408 dispersed therein. The spray process described above typically results in a thicker coating on the top surface 410 of the stent, with a thinner coating on the stent sides 412 and an even thinner coating on the stent bottom surface 414 . However, one should appreciate that the spray coating may be adjusted to control these thicknesses.
[0060] Once the stents have been coated with a drug, they may be loaded onto a delivery catheter and delivered to a target treatment site. FIGS. 5A-5B illustrate an exemplary embodiment of delivery and deployment of a drug eluting stent. In FIG. 5A , standard catheterization techniques are used to introduce a delivery catheter 502 into a coronary artery. Delivery catheter 502 is advanced over a guidewire GW in the coronary artery V having a stenotic lesion L. In this exemplary embodiment, a plurality of stents 506 are disposed over a balloon 504 which is coupled to the delivery catheter 502 near its distal end. A sheath 508 is disposed over the stents 506 in order to protect them during delivery. In FIG. 5B , a single stent 510 is deployed into the lesion L and the delivery catheter is retracted away from the lesion L. The stent 510 now provides mechanical scaffolding to help keep the coronary artery patent and the drug coating can elute into treatment region in order to prevent restenosis. FIGS. 5A-5B show deployment of a single fixed length stent to treat a lesion. In some situations, it is advantageous to be able to customize stent length in situ in order to more accurately match stent length to lesion length. The use of multiple stent segments has been proposed to allow customization of stent length as well as treatment of treatment of multiple lesions. U.S. Patent Publication No. 2007/0027521, entitled “Apparatus and Methods for Deployment of Multiple Custom-Length Prostheses” discloses such a method and the entire contents are incorporated herein by reference. Stents coated with a therapeutic agent as described herein may be delivered using the apparatus and methods described in the aforementioned publication thereby allowing stent length to be customized in situ.
[0061] Portions of stent struts experience high stress and strain during deployment of the stent. For example, FIG. 6A illustrates an unexpanded stent strut 134 having a drug-polymer matrix coating 602 disposed thereon. FIG. 6B shows the same strut 134 after the stent has been expanded. Often with traditional drug coatings, cracking 604 results in the high strain regions of the stent during expansion. Strain can result in delamination of the drug coating from the stent and therefore is undesirable. However, in the present invention, the plasma polymerized tie layer is non-rigid and hence is able to flex with the strut as it expands thereby avoiding cracking and delamination. Other strained regions of the stent may also result in cracking of the tie layer, such as the inner circumferential struts 140 of FIG. 1A . FIG. 6C shows stent strut 134 in the expanded state with no cracks in the drug coating after it has been applied along with a plasma polymerized tie layer according to the methods described herein. Also, in some delivery systems, the stent may be abraded during delivery, resulting in delamination of the drug coating. The polymer anchor layer helps the drug coating to adhere to the stent even under abrasion.
[0062] The following examples illustrate various aspects of fabrication and use of a stent having a plasma polymerized anchor coating with a therapeutic agent disposed thereon according to the methods disclosed herein. These examples are not intended to limit the scope of the present invention.
Example 1
[0063] Cobalt-chromium alloy stents were loaded onto a mandrel and placed into a holding fixture within a Plasma Science PS0500 plasma chamber. A vacuum was drawn inside the chamber and surface cleaning of the stents was performed by plasma treating the stents with oxygen. Next, allyl amine was plasma polymerized onto the stent surface followed by quenching and purging in argon gas. The stents were removed from the plasma chamber and a therapeutic agent, a matrix of Biolimus A9 and polylactide (PLA) in a solvent (acetone) was then sprayed on the plasma polymerized stents. After spraying, the stents were transferred to a vacuum chamber to evaporate the solvent. The therapeutic agent coating was then evaluated by a series of mechanical tests such as scratch testing, followed by visual inspection. Test results demonstrated that the therapeutic agent adhered to the stent and coating integrity was comparable to control stents having a Biolimus A9/PLA matrix deposited over a parylene primer layer that had been applied to the stent using chemical vapor deposition (CVD).
Example 2
[0064] Cobalt-chromium stents were cleaned similarly as above with oxygen. The flow rate for the gas was 350 sccm, and the power was 450 Watts for 5 minutes. Allyl amine or acrylic acid was then plasma polymerized onto the stent surface using a flow rate of 7 ml/hour, at 60% to 80% power (300-400 Watts) for two minutes, followed by quenching and purging under three, one-minute argon gas purges. Biolimus A9/PLA was then sprayed onto the plasma polymer coating as previously described. The coated stents were then terminally sterilized by irradiation with a minimum of 25 kGy. Coated stents were also placed under accelerated aging conditions (approximately 40° C. for ten days) and then crimped onto delivery catheters for deployment. Drug elution testing demonstrated similar elution rates for both the plasma polymerized stents as well as the control samples which had Biolimus A9/PLA deposited over a parylene primer layer deposited using CVD. Coating integrity for the plasma polymerized stents after deployment demonstrated that the coating remained coupled to the deployed stent and test results were comparable to the parylene control group. Similarly 7 day and 28 day animal implant results measured the percent stenosis after implantation into a coronary artery with similar stenosis rates for both the plasma polymerized stents as well as the parylene control stents. Furthermore, biocompatibility testing of the plasma polymerized stents demonstrated that the test stents were non-cytotoxic using an MEM elution as well as non-hemolytic. The plasma polymerization method therefore is a feasible method of coupling a therapeutic agent to a metal stent.
[0065] While the exemplary embodiments have been described in some details for clarity of understanding and by way of example, a variety of additional modifications, adaptations and changes may be clear to those of skill in the art. Hence, the scope of the present invention is limited solely by the appended claims.
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Metallic stents are treated with a gaseous species in a plasma state under conditions causing the species to polymerize and to be deposited in polymerized form on the metallic stent surface prior to the application of a drug-polymer mixture, which is done by conventional non-plasma deposition methods. The drug-polymer mixture once applied forms a coating on the stent surface that releases the drug in a time-release manner and gradually erodes, leaving only the underlying plasma-deposited polymer. In certain cases, the plasma-deposited polymer itself erodes or dissolves into the physiological medium over an extended period of time, leaving only the metallic stent. While the various polymers and drug remain on the stent, the plasma-deposited polymer enhances the adhesion of the drug-polymer anchor coating and maintains the coating intact upon exposure to the mechanical stresses encountered during stent deployment.
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CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
BACKGROUND OF THE INVENTION
Packaging of liquid foodstuffs and the like is most often done with the help of a modern packaging machine which, at a high rate of production, manufactures filled, sealed packages under hygienically acceptable production conditions. Such a packaging machine operates to form, fill and seal a container, such as a gable-top container, from a suitable material, usually plastic-coated paper. In the formation and filling of a gable-top container, flattened blanks are first erected to form open, tubular cartons of generally rectangular cross-section. The blanks are then transferred to a first forming station of the machine which closes and seals one end of each carton. Thereafter, the cartons are typically placed on a conveyor and carried to the filling station of the machine where the cartons are filled with the desired portions of liquid product.
The filling station usually comprises one or more fill pipe assemblies. Each fill pipe assembly is connected to receive product from a product supply tank through an intermediate metering pump. The metering pump is controlled to pump a predetermined volume of product through the fill pipe assembly and into the cartons advanced along a carton transport path immediately below the fill pipe assembly. From the filling station, the filled cartons are conveyed to a final forming station of the machine where the cartons, by means of forming and sealing mechanisms, are given a liquid-tight top closure. Thereafter, the cartons, in the form of finished consumer packages, are discharged from the machine for further distribution.
It is desirable to conduct the packaging operations under hygienic conditions, especially in the packaging of food products. Among other things, this means that machine parts which come into direct contact with the products should be isolated as fully as possible from non-sterile environments of the machine. More importantly, the components of the machine which come into contact with the liquid products must be capable of being cleaned to reduce, if not eliminate, the possibility of contaminating the product as it passes through the filling system and into the containers. One such machine component requiring special attention is the fill pipe assembly.
U.S. Pat. No. 4,964,444 illustrates one manner in which the in-place cleaning of a fill pipe may be accomplished. There, the product fill pipe of the fill pipe assembly is partially surrounded by a tubular casing. The tubular casing is shaped such that a free flow space is formed in the interstitial region between the fill pipe and the casing. The lower end of the casing which faces towards the opening of the fill pipe is cut obliquely to expose the product fill pipe from one direction of view. The casing is adapted so that it can be closed with the aid of a detachable, complimentarily-shaped lid element to form a circulation container which substantially encloses the product fill pipe during a clean-in-place cycle of the machine. During such a cycle, cleaning solution is passed through the product fill pipe and into the circulation container whereby both the interior and exterior of the product fill pipe are cleaned.
In addition to the device disclosed in the above-described patent, a variety of other apparatus have been directed to clean-in-place operations. Examples of such improvements may be found in the following U.S. Patents.
U.S. Pat. No. 4,964,444 Issued Oct. 23, 1990
U.S. Pat. No. 4,688,611 Issued Aug. 25, 1987
U.S. Pat. No. 4,593,730 Issued Jun. 10, 1986
U.S. Pat. No. 4,527,377 Issued Jul. 9, 1985
U.S. Pat. No. 4,396,044 Issued Aug. 2, 1983
U.S. Pat. No. 3,513,024 Issued May. 19, 1970
U.S. Pat. No. 4,218,265 Issued Aug. 19, 1980
U.S. Pat. No. 3,430,639 Issued Mar. 4, 1969
Notwithstanding the foregoing, the present inventors have recognized that the standard process of altering a filling system configuration between a production cycle and a clean-in-place cycle is relatively laborious and time-consuming. As the present inventors have recognized, this is due, at least in part, to the extensive steps required to attach and detach a cleaning apparatus/system to a fill pipe assemble. Accordingly, the present inventors have set forth herein an apparatus that facilitates quick and easy configuration of the fill station of the packaging machine between a production cycle and a clean-in-place cycle of the machine.
BRIEF SUMMARY OF THE INVENTION
A system for facilitating a clean-in-place operation of a filling station of a packaging machine is set forth. The system comprises a fill pipe assembly having a discharge end through which the liquid product may flow into a container disposed therebelow during a production cycle of the machine. A clean-in-place manifold is provided and is adapted to engage and seal with the discharge end of the fill pipe during the clean-in-place operation. A lift mechanism is utilized in a dual function role. The lift mechanism is operated during a container-filling cycle to lift and lower a container toward and away from the discharge end of the fill pipe assembly for filling with product and is operated during the clean-in-place operation to engage the clean-in-place manifold and to secure the clean-in-place manifold in engagement with the discharge end of the fill pipe assembly.
The manifold may include an input port into which a discharge end of a fill pipe may be inserted for a clean-in-place operation. The manifold may further include an output port for attachment to a fluid-conducting outlet pipe that extends between the manifold and, for example, a recirculation input or a drain.
The input port of the manifold is preferably provided with an inner-circumferential surface having a groove into which a flexible sealing gasket is secured. The physical characteristics of this sealing gasket are such that it is placed in leak proof engagement with an exterior surface of the discharge end of the fill pipe as such discharge end is inserted into the input port of the manifold. The sealing gasket is preferably designed to withstand any increased pressure which is placed upon it during a clean-in-place operation and, even more preferably, serves to provide a stronger seal with the fill pipe under such conditions.
The manifold also includes an inverted, cup-shaped seat mounted on its underside. This seat is designed for complementary engagement with the container lift rod of the lift mechanism. This lift rod engages the seat and preferably functions to lift, and maintain, the manifold into the proper operational position for a clean-in-place operation.
In a preferred method of operation, the clean-in-place manifold is positioned beneath the discharge end of the fill pipe assembly so that the lift rod engages the seat of the manifold. The lift rod is operated to move vertically a predetermined distance to urge the inlet port of the manifold into secured and sealed engagement with the discharge end of the fill pipe. The lift rod of the lift mechanism maintains the manifold in such engagement throughout the clean-in-place cycle of operation of the machine. As will suggest itself, no additional tools, clamps, or other mechanical means are necessary to secure the clean-in-place manifold to the fill pipe during the clean-in-place operation, although such mechanical securements are not necessarily precluded.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a perspective view of one embodiment of a filling system of the present invention during a production cycle of operation of the packaging machine.
FIG. 2 is a perspective view of a further embodiment of a filling system of the present invention during a production cycle of operation of the packaging machine.
FIG. 3 is a perspective view of one embodiments of a clean-in-place manifold of the present invention that may be used with the embodiments of the filling systems of FIGS. 1 and 2 during a clean-in-place cycle of operation of the packaging machine.
FIG. 4 is a further perspective view of the embodiment of the clean-in-place manifold of FIG. 3.
FIG. 5 is a side view of the filling system of FIG. 1 wherein the clean-in-place manifold is engaged by a lift member of the lifting mechanism and disposed below a fill pipe prior to operational engagement therewith.
FIG. 6 is a side view of the filling system of FIG. 5 wherein the clean-in-place manifold is in operational engagement with the fill pipe, the clean-in-place manifold being supported in place by a lift rod of a liquid packaging machine.
FIG. 7 is a side view of the clean-in-place manifold in operational engagement with a fill pipe assembly such as the one set forth in FIG. 2.
FIG. 8 is a side cross-sectional view of the clean-in-place manifold and the associated fill pipe.
FIG. 9 is a side cross-sectional view of the clean-in-place manifold having the associated liquid fill pipe inserted therein for a clean-in-place cycle of machine operation.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, one embodiment of a filling assembly 10 of a packaging machine is shown operating in a production cycle. The filling assembly includes a fill pipe 15 having a discharge end 20 that, depending on the type of filling system and nature of the dispensed product, may have a flexible, pressure-actuated nozzle disposed thereover. A radially extending collar 25, formed either integral with the fill pipe 15 or as a separate piece that joins the body of the fill pipe to the discharge end 20, is disposed proximate the discharge end 20. A lift mechanism 30 having, for example, a lift rod 35 for engaging a container is disposed below the discharge end 20 of the fill pipe 15. Such system may also advantageously incorporate the use of external container guides 37 and 38.
In accordance with a production cycle of the packaging machine, a container 40 (typically one of a plurality of containers on container supports disposed on an endless conveyor belt) is engaged on its underside by the lift rod 35 of the lift mechanism 30 and is driven vertically so that the container 40 is placed proximate the discharge end 20 of the fill pipe 15 so that the container 40 may receive the desired product from fill pipe 15. As container 40 is being raised into the proper filling position, corners 45 and 50 of the container are securely received between respective parallel rails of the external container guides 37 and 38 to ensure that container 40 maintains a proper shape and orientation during the filling process. Thus, the container 40 remains properly aligned with the discharge end 20 of the fill pipe 15 even when it is raised above the supports of the endless belt conveyor As product is being discharged into the container 40, the lift mechanism 30 lowers the container 40 in accordance with a predetermined motion profile until it is again disposed in the carton supports of the endless belt conveyor (not illustrated). Preferably, particularly in instances in which a liquid product is discharged into the container 40, the lift mechanism 30 lowers the container 40 so as to maintain the nozzle (not illustrated) that is disposed at the discharge end 20 below the level of the liquid in the container 40. The vertical movement described is shown generally at 65.
FIG. 2 shows another embodiment of a filling assembly 10 of a packaging machine. The filling assembly shown here is similar to the embodiment described in connection with FIG. 1. This filling assembly 10, however, includes internal container guides 70 and 75 mounted upon fill pipe 15 so as to engage internal diagonal comers of the container 40 as it is raise and lowered to and from the discharge end 20 of the fill pipe 15 during the production cycle. With reference to FIG. 2, internal container guides 70 and 75 serve to engage, and securely position, the internal surfaces of comers 80 and 85 of container 40. Such practice again ensures that container 40 remains in the proper shape and orientation throughout the filling operation.
Turning now to FIGS. 3 and 4, one embodiment of a clean-in-place manifold 100 is shown. The manifold includes a body portion 105 having an inlet port, shown generally at 110, an outlet port shown generally at 115, and a rod seat shown generally at 117. If the external carton guides 55 and 60 of the system of FIG. 1 are used, the body portion 105 is preferably provided with an optional pair of guide pins 125.
Inlet port 110 comprises a lip portion 130 that has an inside diameter 135 which is dimensioned to receive the discharge end 20 of the fill pipe 15 therein. The inlet port 110 further includes a sealing gasket 140 which, as will be discussed in further detail below, is secured within the inlet port 110 to seal with collar 25 of the fill pipe 15.
The outlet port 115 includes an integrally-formed flange member 120 that, for example, is dimensioned to engage a corresponding flange of a further pipe at a tri-clamp connection. Accordingly, the outlet port 115 may be provided with a groove 145 in the flange member 120 which is dimensioned and shaped to engage a corresponding gasket or O-ring to provide a seal with the further pipe. Such a further pipe may extend between the manifold 100 and, for example, a recirculation input or a drain of the packaging machine.
With reference to FIG. 4, the rod seat 117 of the illustrated embodiment is shown as a structure that is disposed at the bottom of manifold 100. Seat 117 of the embodiment has an inverted, cup-shape which defines a seat cavity 150 having an interior diameter 155 which is dimensioned to engage the lift rod 35, or other lifting member, of the lift mechanism 30. It will be recognized, however, that the seat 117 may take on any number of shapes, the particular shape being dependent on the type and shape of the engagement member of the left mechanism 35 that is used.
Operation of the filling system 10 of the embodiment of FIG. 1 pursuant to a clean-in-place cycle of the machine can be described in connection with FIGS. 5 and 6. As illustrated, the preferred embodiment of the clean-in-place manifold 100 is initially positioned, either manually or automatically, immediately beneath the discharge end 20 of fill pipe 15 in preparation for a clean-in-place operation. In this position, the rod 35 of the lift mechanism 30 preferably is seated within the rod seat 117. Additionally, when the manifold 100 is in this position, guide pins 125 are aligned with the regions between the rails of the external container guides 37 and 38.
Once in the position illustrated in FIG. 5, the lift mechanism 30 is operated to drive the lift rod 35 and the manifold 100 to the position illustrated in FIG. 6. Such actuation may be accomplished, for example, through depression of a key or other form of switch by the machine operator, or in an automatic timed relationship with the initial positioning of the manifold 100 in the position of FIG. 5. In the position of FIG. 6, the collar 25 at the discharge end 20 of the fill pipe 15 is disposed within the inlet port 110 of the manifold 100 and seals therewith. Additionally, the guide pins 125 are disposed between respective rails of the external container guides 37 and 38. Once in this position, the fill system 10 is mechanically ready to undergo a clean-in-place operation. During a clean-in-place cycle of the packaging machine, the lift mechanism 35 is used to maintain the manifold 100 in the illustrated position.
The embodiment shown in FIG. 5 also illustrates the engagement between the outlet port 115 and a corresponding pipe 170. Specifically, flange member 120 is formed to readily connect to another similarly-formed flange member 175 of pipe 170. Securement between flange member 120 and flange member 175 may be accomplished in any number of known ways, including tri-clamps, bolts, etc..
FIGS. 8 and 9 illustrate one manner of engagement between the discharge end 20 of the fill pipe 15 and the inlet port 110 of the manifold 100, with FIG. 8 illustrating the system prior to engagement between the discharge end 20 and the inlet port 110 and FIG. 9 illustrating the system as fully engaged. As illustrated, inlet port 110 is defined by a wall having a thickness 200 sufficiently thick so as to have a groove 205 formed therein. Groove 205 is dimensioned to serves as a receptacle into which the sealing gasket 140 is secured. Sealing gasket 140 has an inverted U-shaped cross-section comprising a rear edge 215, a top edge 220 and a sealing edge 225. Such U-shape also results in the formation of a pocket area 230 on the underside of sealing gasket 140. As may be observed in FIG. 8, rear edge 215 and top edge 220 of sealing gasket 140 are mounted within groove 205 whereas sealing edge 225 extends inwardly and downwardly therefrom.
With reference to FIG. 9, as manifold 100 is raised so as to allow discharge end 20 and collar 25 to pass through inlet port 110 into the interior of body portion 105, sealing edge 225 of sealing gasket 140 is compressed into liquid-tight engagement with a circumferential exterior surface of collar 25. Given that the manifold 100 is maintained in this position throughout the clean-in-place cycle via the lift rod 35, no additional mechanical components and no other tools are required to further secure the manifold 100 with the discharge end 20 of the fill pipe 15.
The body thickness 235 of body portion 105 is thinner than wall thickness 200 of inlet port 110. This decrease in thickness corresponds to an increased internal flow region 240. Such space allows discharge end 20 to have the maximum exposure to cleaning fluids coming to/from fill pipe 15 and pipe 170 during a clean-in-place operation.
A clean-in-place operation may be accompanied by increased fluid pressure within the body portion 105 of manifold 100. The pocket area 230 of the sealing gasket 140 of the preferred embodiment accepts fluid at this increased pressure therein whereby an additional force on sealing edge 225 results in an even stronger seal between sealing edge 140 and the circumferential surface of collar 25. After the clean-in-place operation is completed, pressure within the body 105 is reduced to a normal level. Thereafter, the lift mechanism 35 is operated to lower the lift rod 35 and manifold 100 to facilitate removal of the manifold 100 to place the machine in a mechanical state suitable for a production cycle of machine operation.
FIG. 7 illustrates engagement between the manifold 100 and the filling system of FIG. 2. As shown, the manifold 100 is not provided with the guide pins 125 since the fill pipe 15 is instead provided with internal container guides 70 and 75. However, the internal container guides 70 and 75 are tapered proximate the discharge end 20 of the fill pipe 15 so that they do not interfere with the proper engagement between the discharge end 20 and the inlet port 110 of the manifold 100.
Although not particularly pertinent to the claimed invention, it is worth noting, with reference to FIGS. 5, 6 and 7, that the lift rod 35 may extend through a bushing not shown disposed in a table not shown of the packaging machine. Preferably, the bushing is supplied with a flow of cleaning/lubricating fluid. Such a bushing is disclosed in co-pending U.S. patent application Ser. No. 08/825,207, filed on Mar. 28, 1997, entitled Improved Seal For A Reciprocating Rod Of A Packaging Machine.
Although the present invention has been described with reference to a specific embodiment, those of skill in the art will recognize that changes may be made thereto without departing from the scope and spirit of the invention as set forth in the appended claims.
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A system for facilitating a clean-in-place operation of a filling station of a packaging machine is set forth. The system comprises a fill pipe assembly having a discharge end through which the liquid product may flow into a container disposed therebelow during a production cycle of the machine. A clean-in-place manifold is provided and is adapted to engage and seal with the discharge end of the fill pipe during the clean-in-place operation. A lift mechanism is utilized in a dual function role. The lift mechanism is operated during a container-filling cycle to lift and lower a container toward and away from the discharge end of the fill pipe assembly for filling with product and is operated during the clean-in-place operation to engage the clean-in-place manifold and to secure the clean-in-place manifold in engagement with the discharge end of the fill pipe assembly.
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FIELD OF INVENTION
The present invention relates to a particulate carrier for delivering materials having biological activity. The term "microparticle" as used herein refers to any particulate carrier used for delivery of a biologically-active material and includes materials which are microcapsules and microspheres.
BACKGROUND OF THE INVENTION
Vaccines have been used for many years to protect humans and animals against a wide variety of infectious diseases. Such conventional vaccines consist of attenuated pathogens (for example, polio virus), killed pathogens (for example, Bordetella pertussis) or immunogenic components of the pathogen (for example, diphtheria toxoid). Some antigens are highly immunogenic and are capable alone of eliciting protective immune responses. Other antigens, however, fail to induce a protective immune response or induce only a weak immune response. This low immunogenicity can be significantly improved if the antigens are co-administered with adjuvants. Adjuvants enhance the immunogenicity of an antigen but are not necessarily immunogenic themselves. Adjuvants may act by retaining the antigen locally near the site of administration to produce a depot effect facilitating a slow, sustained release of antigen to cells of the immune system. Adjuvants can also attract cells of the immune system to an antigen depot and stimulate such cells to elicit immune responses. Adjuvants have been identified that enhance the immune response to antigens delivered parenterally. Some of these adjuvants are toxic, however, and can cause undesirable side-effects, making them unsuitable for use in humans and many animals. Indeed, only aluminum hydroxide and aluminum phosphate are routinely used as adjuvants in human and veterinary vaccines. However, even these adjuvants are not suitable for use with all antigens and can also cause irritation at the site of injection. There is a clear need to develop novel adjuvants which are safe and efficacious for enhancing the immunogenicity of antigens.
Immunization can also be achieved by the delivery of antigens to mucosal surfaces, such as by ingestion of the antigen. Thus, it is known that the ingestion of antigens by animals can result in the appearance of antigen-specific secretory IgA antibodies in intestinal, bronchial or nasal washings and other external secretions. For example, studies with human volunteers have shown that oral administration of influenza vaccine is effective at inducing secretory anti-influenza antibodies in nasal secretions and substances have been identified which might be useful as adjuvants for such ingested vaccines. However, most of these adjuvants are relatively poor in terms of improving immune responses to ingested antigens. Currently, some of these adjuvants have been determined to be safe and efficacious in enhancing immune responses in humans and animals to antigens that are administered via the orogastrointestinal, nasopharyngeal-respiratory and genital tracts or in the ocular orbits. However, administration of antigens via these routes is generally ineffective in eliciting an immune response. The inability to immunize at the mucosal surface is generally believed to be due to:
the destruction of the antigen or a reduction in its immunogenicity in the acidic and/or enzymatically hostile environments created by secretions produced at the mucosal epithelium;
the dilution of the antigen to a concentration that is below that required to induce immune responses;
the carriage of antigen from the body in discharges originating at the mucosal epithelium; and the lack of suitable adjuvants which remain active at the mucosal epithelium.
Clearly, there is a need to identify powerful adjuvants which are safe and efficacious for use at the mucosal epithelium in the orogastrointestinal, nasopharyngeal-respiratory and urogenital tracts and in the ocular orbits and at other mucosal sites.
Sensitive antigens may be entrapped to protect them against destruction, reduction in immunogenicity or dilution. The antigen can be coated with a single wall of polymeric material or can be dispersed within a monolithic matrix. Thus, U.S. Pat. No. 5,151,264 describes a particulate carrier of a phospholipid/glycolipid/polysaccharide nature that has been termed Bio Vecteurs Supra Moleculaires (BVSM). The particulate carriers are intended to transport a variety of molecules having biological activity in one of the layers thereof. However, U.S. Pat. No. 5,151,264 does not describe particulate carriers containing antigens for immunization and particularly does not describe particulate carriers for immunization via the orogastrointestinal, nasopharyngeal-respiratory and urogenital tracts and in the ocular orbits or other mucosal sites.
U.S. Pat. No. 5,075,109 describes encapsulation of the antigens trinitrophenylated keyhole limpet hemocyanin and staphylococcal enterotoxin B in 50:50 poly (DL-lactide-co-glycolide). Other polymers for encapsulation are suggested, such as poly(glycolide), poly(DL-lactide-co-glycolide), copolyoxalates, polycaprolactone, poly(lactide-co-caprolactone), poly(esteramides), polyorthoesters and poly(8-hydroxybutyric acid), and polyanhydrides. The encapsulated antigen was administered to mice via gastric intubation and resulted in the appearance of significant antigen-specific IgA antibodies in saliva and gut secretions and in sera. As stated in this patent, in contrast, the oral administration of the same amount of unencapsulated antigen was ineffective at inducing specific antibodies of any isotype in any of the fluids tested. Poly(DL-lactide-co-glycolide) microcapsules were also used to administer antigen by parenteral injection.
Published PCT application WO 91/06282 describes a delivery vehicle comprising a plurality of bioadhesive microspheres and antigenic vaccine ingredients. The microspheres being of starch, gelatin, dextran, collagen or albumin. This delivery vehicle is particularly intended for the uptake of vaccine across the nasal mucosa. The delivery vehicle may additionally contain an absorption enhancer. The antigens are typically encapsulated within protective polymeric materials.
SUMMARY OF THE INVENTION
The present invention is directed towards the provision of a new and useful microparticle delivery system, which may be used for delivery of materials having biological activity, including antigens to a host.
In accordance with one aspect of the present invention, there is provided a particulate carrier, which comprises:
a solid core comprising a polysaccharide and a proteinaceous material; and
an organometallic polymer bonded to the core. Such particulate carrier generally has a particle size from about 10 nm to about 50 μm, preferably from about 1 to about 10 μm.
The polysaccharide component of the core may be dextran, starch, cellulose or derivatives thereof, particularly soluble starch. The starch may be derived from a variety of monocotyledenous and dicotyledenous species, such as corn, potato or tapioca.
The proteinaceous material component of the core may have biological activity. An additional material having biological activity also may be included in the core. The particles then provide a delivery vehicle for the biologically-active material to a host, generally an animal, including a human.
The material having biological activity, for example, immunogenicity, includes proteins (such as influenza viral protein), peptides, antigens, bacteria, bacterial lysates, viruses (such as, influenza virus), virus-infected cell lysates (such as, a herpes simplex virus-infected cell lysate), antibodies, carbohydrates, nucleic acids, lipids, haptens, pharmacologically-active materials, and combinations, derivations and mixtures thereof.
The organometallic polymer bonded to the core preferably is derived from a functionalized silicone, including an end-substituted silicone. One particular class of end-substituted silicones from which the organometallic polymer may be derived are (trialkoxysilyl) alkyl-terminated polydialkxylsiloxanes.
In a further aspect of the present invention, there is provided an immunogenic composition formulated for mucosal or parenteral administration, comprising the particulate carrier containing an immunogenic material and a physiologically-acceptable carrier therefor.
In an additional aspect, there is provided a method of producing an immune response in a host, comprising the administration thereto, generally by mucosal or parenteral administration, the immunogenic composition provided herein. The immune response produced may be an antibody response, including local and serum antibody responses.
In a further aspect of the present invention, there is provided a method for producing a particulate carrier, which comprises:
(a) forming an aqueous composition comprising a dissolved polysaccharide and a dispersed or dissolved proteinaceous material;
(b) forming an emulsion in which the aqueous composition is the dispersed phase;
(c) forming from the emulsion a particulate carrier comprising a core of said polysaccharide and proteinaceous material having bonded thereto an organometallic polymer; and
(d) collecting the particulate carrier so formed.
The method may optionally include a step of sonicating the suspension of microspheres to produce a fine suspension before the forming step (c), so as to control particle size.
This procedure enables the proteinaceous material to be incorporated into the microparticles under temperature conditions which do not denature the proteinaceous material or adversely affect the biological activity thereof.
Advantages of the present invention include:
(a) ease and safety of microparticle manufacture;
(b) biocompatability and safety of the microparticles;
(c) improved immunogenicity of antigens presented to cells of the immune system by the microparticles;
(d) ease of storage and administration; and
(e) fabrication conditions that do not adversely affect the biological activity of proteinaceous or other material.
In this application, the term "coated" microparticles is used to define microparticles that have a long chain organometallic polymer bound, bonded or otherwise associated with the core thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a flow diagram for a process for the production of starch microparticles according to one embodiment of the invention. In this Figure, HSA=human serum albumin, HSV2-lysate/HSA=herpes simplex virus type-2 lysate mixed with human serum albumin, Flu X31/HSA =influenza virus strain X31 mixed with human serum albumin.
FIG. 2 shows scanning electron microscopy (SEM) analysis of influenza virus strain A-X31 and human serum albumin--containing microparticles that were either (A) coated with the silicone polymer s(triethoxysilyl)propyl-terminated polydimethysiloxane (TS-PDMS) or (B) were uncoated. The SEM images represent magnification of 2500 diameters. The nominal diameter of the TD-PDMS-coated microparticles was 10 μm and that of uncoated microparticles was 10 μm.
FIG. 3 shows the diameter distribution of human serum albumin-containing starch microparticles coated with the silicone polymer 3-(triethoxyl) silylpropyl-terminated polydimethylsiloxane (TS-PDMS). HSA-containing starch particles (Δ) were fabricated and compared to polystyrene microsphere standards by flow cytometry ( -▪-; 10 μm, 7 μm, 4 μm diameter). The particles had a mean diameter of 4.18 μm and a standard deviation of plus or minus 3 μm.
FIG. 4 shows an immunoblot analysis of human serum albumin released from human serum albumin-containing starch microparticles that were either coated with the silicone polymer 3-(triethoxysilyl)propyl-terminated polymethylsiloxane (TS-PDMS) or uncoated following suspension of the microparticles in phosphate buffered saline (PBS). Lane 1 shows 0.5 μg of an HSA standard. Lanes 2 to 4 show HSA released from TS-PDMS coated microparticles incubated for 30 min. 1h and 3h in PBS in vitro and lanes 5 to 7 show HSA released from uncoated microparticles at 30 min., 1h and 3h in vitro.
FIG. 5 shows the anti-HSA IgG serum antibody responses following various immunization protocols. Groups of 6 mice were immunized intraperitoneally (I.P.) on days 0, 7 and 14 with 250 μL of PBS, pH 7.4, containing 100 μg of HSA incorporated into TS-PDMS-coated or uncoated starch microparticles. Sera obtained on days 21, 35, 49, 63 and 84 were evaluated for the presence of anti-HSA IgG antibodies using an enzyme-linked immunosorbent assay (ELISA). 1 mg of coated or uncoated microparticles contains 50 μg of HSA.
FIG. 6 shows the percentage of animals developing an anti-HSA IgG serum antibody response following intragastric immunization with HSA incorporated into uncoated or TS-PDMS coated microparticles.
FIG. 7 shows the anti-HSA IgG serum antibody titres in six mice immunized intragastrically with a 50 μg dose of uncoated or TS-PDMS coated microparticles. Animals were immunized on days 0, 7 and 14 with 0.5 mL of 0.2M NaHCO 3 containing 50 μg of HSA incorporated into TS-PDMS-coated or uncoated starch microparticles or soluble HSA. Sera obtained on days 21, 35, 49, 63 and 84 were evaluated for the presence of anti-HSA IgG antibodies using an ELISA. 1 mg of coated or uncoated microparticles contains 50 μg of HSA.
FIG. 8 shows the anti-HSA IgG serum antibody titres in six mice immunized intragastrically with a 75 μg dose of uncoated or TS-PDMS coated microparticles. Animals were immunized on days 0, 7 and 14 with 0.5 mL of 0.2M NaHCO 3 containing 75 μg of HSA incorporated into TS-PDMS-coated or uncoated starch microparticles or soluble HSA. Sera obtained on days 21, 35, 49, 63 and 84 were evaluated for the presence of anti-HSA IgG antibodies using an ELISA. 1 mg of coated or uncoated microparticles contains 50 μg of HSA.
FIG. 9 shows the anti-Flu X31 (i.e. influenza virus type A strain X31) serum antibody titres in mice immunized by the intraperitoneal route with soluble Flu X31/HSA, Flu X31/HSA mixed with microparticles coated with TS-PDMS or Flu X31HSA entrapped in TS-PDMS-coated microparticles.
FIG. 10 shows the anti-HSA antibody titres in the sera of mice immunized by the intraperitoneal route with soluble Flu X31/HSA, Flu X31/HSA mixed with microparticles coated with TS-PDMS or Flu X31/HSA entrapped in TS-PDMS-coated microparticles.
FIG. 11 shows the anti-Flu X31 antibody titres in the sera of mice immunized by the intranasal route with soluble Flu X31/HSA or Flu X31/HSA entrapped in TS-PDMS-coated microparticles.
FIG. 12 shows the anti-HSA antibody titres in the sera of mice immunized by the intranasal route with soluble Flu X31/HSA or Flu X31/HSA entrapped in TS-PDMS-coated microparticles.
GENERAL DESCRIPTION OF THE INVENTION
As noted above, the present invention relates to a particulate carrier or microparticle, which is useful for the delivery of biologically-active materials to a vertebrate, generally an animal including humans, including the delivery of antigens to the immune system, by mucosal or parenteral administration.
The particulate carrier comprises two components, namely a solid core and an organometallic polymer bonded to the core.
The solid core comprises at least two components, namely a polysaccharide and a proteinaceous material. The polysaccharide may be one of a wide range of such materials, preferably starch, particularly starch which has been treated as to be "soluble" starch (i.e. a starch which has been treated to provide a starch which is soluble in water). However, other polysaccharide materials may be used, including dextran and cellulose, as well as derivatives and mixtures of two or more polysaccharides.
The particulate carrier may have a particle size which generally ranges from about 10 nm to about 50 μm and preferably about 1 to about 10 μm for mucosal administration of antigens.
The proteinaceous material may be any desired proteinaceous material and may itself have biological activity. Examples of proteinaceous materials which may be used are proteins derived from a variety of viruses and bacteria including tetanus toxoid, diphtheria toxoid, cholera toxoid and subunits thereof, pertussis toxoid, viral subunits, such as rubella virus proteins E1, E2 and C, bacterial subunits, such as the P41, OspA and OspB proteins of B. burgdorferi, protein-polysaccharide conjugates, protozoan subunits, such as T. gondi P30, anticoagulants, venoms, such as snake venom, cytokines, such as interleukins 4, 5, 6 and 12, interferons, tumour necrosis factor, and albumins, such as human serum albumin, bovine serum albumin and ovalbumin, as well as recombinant proteins, peptides and lipopeptides and analogs thereto, including muramyl dipeptide, lipopolysaccharide and lipid A or analogues of such proteins or of immunologic regions of such proteins.
Where the proteinaceous material has biological activity, an additional biologically-active material may or may not be included in the core. Where the proteinaceous material lacks biological activity, a material having biological activity may be incorporated into the core, so that the proteinaceous material acts as a carrier for the biologically-active material.
Both the polysaccharide and proteinaceous material are required to be present for microparticle formation and organometallic polymer coating. In the absence of one of the components, it has not been possible to obtain the particulate carrier of the invention. The proportion of the core comprising proteinaceous material may vary up to about 33 wt % of the core, generally from about 0.5 wt % to about 10 wt %.
Where a biologically-active material is present in the core other than in the form of the proteinaceous material, such material may comprise from about 0.5 to about 30 wt % of the core, preferably from about 0.5 to about 5.0 wt %. Such biologically-active material may be any member of the various classes of known biologically-active materials, including proteins, peptides, antigens, antibodies, immunotargeting molecules, bacteria, bacterial lysates, viruses, virus-infected cell lysates, antibodies, carbohydrates, nucleic acids, lipids, glycolipids, haptens, pharmacologically-active materials, as well as combinations, derivatives and mixtures thereof. Specific examples of such materials include influenza viruses, parainfluenza viruses, respiratory viruses, measles viruses, mumps viruses, human immunodeficiency viruses, polio viruses, rubella viruses, herpex simplex viruses type 1 and 2, hepatitis viruses types A, B and C, yellow fever viruses, smallpox viruses, rabies viruses, vaccinia viruses, reo viruses, rhinoviruses, Coxsackie viruses, Echoviruses, rotaviruses, papilloma viruses, paravoviruses and adenoviruses; E. coli, V. cholera, BCG, C. diphtheria, Y. pestis, S. typhi, B. pertussis, S. aureus, S. pneumoniae, S. pyogenes, S. mutans, Myocoplasmas, Yeasts, C. tetani, meningococci (N. meningitdis), Shigella spp, Campylobacter spp, Proteus spp, Neisseria gonorrhoeae, and Haemophilus influenzae; as well as proteins obtained from such viruses and bacteria.
The solid core has an organometallic polymer bonded to thereto. Such organometallic compounds may include linear, branched or cross-linked silicones which are bonded at the ends of polymer chains to the core, although the polymer may be bonded to the core at locations along the length of the chain. Such polysiloxanes may vary in molecular weight from about 400 up to about 1,000,000 Daltons and preferably from about 700 to about 60,000 Daltons.
A variety of polysiloxanes may be employed. For the purpose of bonding the polysiloxane to the solid core, the polysiloxanes preferably are derived from functionalized materials which have functional groups at the ends of the polymer chain which facilitate bonding the ends of the polysiloxane chain to the solid core. Preferably, however, where such functional groups are present, they are joined to the polysiloxane chain through end-blocking groups.
Suitable functionalized silicones useful for forming the products of the invention include (trialkoxysilyl) alkyl-terminated polydialkylsiloxanes and trialkoxysilylterminated polydialkylsiloxanes. One useful member of this group of compounds is 3-(triethoxysilyl) propyl-terminated polydimethylsiloxane (herein abbreviated as TS-PDMS).
The organometallic polymer is present in the particulate carrier in relatively minor amounts, generally from about 0.5 to about 5 wt % of the solid core. The presence of the organometallic polymer, particularly a silicone, bonded to the solid core enables biologically-active materials to be administered to a host, particularly by mucosal administration, to achieve an enhanced biological response to such material, for example, an enhanced immune response to an antigen, in comparison to delivery of the material by the same particulate material without the organometallic polymer bonded thereto, as seen from the data presented herein.
The particulate carrier provided herein may be formed in any convenient manner permitting coated particle formation. One preferred procedure is described below with reference to FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a method for preparing starch microparticles according to one embodiment of the present invention. Antigen-containing starch microparticles are manufactured by mixing starch and the antigen in solvents, forming an emulsion in oil, and then dispersing the emulsion into an acetone solution with vigorous stirring and collecting the particles formed. The starch or other polysaccharide first is dissolved in a solvent suitable for the polysaccharide. For starch, dimethylsulfoxide is a preferred solvent, in which starch, for example, "soluble" starch, is dissolved at a elevated temperature, for example, a temperature of about 50° to about 100° C., preferably about 75° to about 90° C. and then cooled to a lower temperature, particularly to a temperature below about 35° C., without precipitating therefrom. Alternative polar solvents which may be used as solvents for the starch, including dimethylformamide as well as various alcohols.
The starch solution is mixed with an aqueous solution and/or dispersion of a proteinaceous material, in the illustrated embodiment, human serum albumin (HSA), which may be used alone as an antigen or combined with other antigenic material, for example, a herpes simplex virus type 2 (HSV-2) infected cell lysate or a whole influenza virus (Flu X31), in which event the HSA acts also as a carrier protein.
Mixing of the starch solution and antigen composition generally produces by stirring, a highly viscous mixture, which then is added dropwise into vegetable oil, or other water-immiscible fluid which is capable of forming a water-in-oil emulsion, including silicone oils or derivatives thereof or mixtures thereof, with vigorous stirring to promote the formation of a water-in-oil emulsion, in which droplets of the starch-proteinaceous material composition are dispersed in the vegetable oil. This step of the process, therefore, involves forming an emulsion in which the aqueous composition is the dispersed phase.
The particle size of the liquid droplets, which determines the size of the ultimate carrier microparticles, is determined by the volumetric ratio of aqueous phase to oil phase, by the degree of stirring of the water-in-oil emulsion and may further be controlled by sonication. Additional control of particle size may be achieved by employing a surfactant in the oil, such as non-ionic surfactants of the TWEEN or SPAN type.
The water-in-oil emulsion then may be added dropwise to a solvent for the oil and aqueous medium containing the starch, proteinaceous material and antigen, to result in microparticle formation. In the procedure of the present invention, the solvent also contains a silicone polymer material which can bond to the solid core produced by the solvent. Alternatively, some or all the silicone oil can be included in the vegetable oil or silicone oil can replace all or part of the vegetable oil. (FIG. 1 also illustrates an alternative procedure, employed in the Examples below to produce particulate carrier lacking the silicone polymer, for comparative experimentation.)
The solvent which may be employed for such dessication and oil dissolution may be any organic solvent miscible with the oil and water phases of the emulsion and in which the starch and proteinaceous material are substantially insoluble. Such solvents include but are not limited to ketones, such as acetone and methyl ethyl ketone.
The silicone polymer dissolved in the solvent may be a functionalized polysiloxane, particularly end-functionalized, to permit bonding of the polysiloxane to the solid core of the particulate material. Such functionalized polysiloxane may include 3-(trialkoxysilyl) alkyl-terminated polydialkylsiloxanes, particularly 3-triethoxysilyl) propyl-terminated polydimethylpolysiloxane (TS-PDMS).
The resulting particulate material may be harvested from the residual medium by any convenient means, including centrifugation, separated and dried. The particulate material resulting from this procedure then is in a suitable form for formulation for administration of the biologically-active material.
It is clearly apparent to one skilled in the art, that the various embodiments of the present invention have many applications in the fields of medicine and in particular vaccination, diagnosis and treatment of infections with pathogens including bacteria and viruses. A further non-limiting discussion of such uses is further presented below.
Vaccine Preparation and Use
In an embodiment, immunogenic compositions, suitable to be used as, for example, vaccines, may be prepared from microparticles as disclosed herein. The immunogenic composition elicits an immune response by the host to which it is administered including the production of antibodies by the host.
The immunogenic composition may be prepared as injectables, as liquid solutions or emulsions. The microparticles may be mixed with physiologically acceptable carriers which are compatible with the microparticles. These may include, water, saline, dextrose, glycerol, ethanol and combinations thereof. The vaccine may further contain auxiliary substances such as wetting or emulsifying agents, pH buffering agents, or adjuvants to further enhance the effectiveness of the vaccines. Vaccines may be administered by injection subcutaneously or intramuscularly.
Alternatively, and in a preferred embodiment, the immunogenic compositions comprising microparticles formed according to the present invention, may be delivered in a manner to evoke an immune response at mucosal surfaces. Thus, the immunogenic composition may be administered to mucosal surfaces by, for example, the nasal or oral (intragastric) routes. Alternatively, other modes of administration including suppositories may be desirable. For suppositories, binders and carriers may include, for example, polyalkylene glycols and triglycerides. Oral formulations may include normally employed incipients, such as pharmaceutical grades of saccharine, cellulose and magnesium carbonate.
These compositions may take the form of solutions, suspensions, tablets, pills, capsules, sustained release formulations or powders and contain 1 to 95% of the microparticles of the present invention. In order to protect the microparticles and the material having biological activity contained within the core of the microparticle, from gastric acidity when administered by the oral route, an acidic neutralizing preparation (such as a sodium bicarbonate preparation) is advantageously administered before, concomitant with or directly after administration.
The vaccines are administered in a manner compatible with the dosage formulation, and in such amount as to be therapeutically effective, protective and immunogenic. The quantity to be administered depends on the subject to be treated, including, for example, the capacity of the subject's immune system to synthesize antibodies, and if needed, to produce a cell-mediated immune response. Precise amounts of microparticle and material having biological activity required to be administered depend on the judgement of the practitioner. However, suitable dosage ranges are readily determinable by one skilled in the art and may be of the order of micrograms to milligrams. Suitable regimes for initial administration and booster doses are also variable, but may include an initial administration followed by subsequent administrations. The dosage of the vaccine may also depend on the route of administration and will vary according to the size of the host.
EXAMPLES
The above disclosure generally describes the present invention. A more complete understanding can be obtained by reference to the following specific Examples. These Examples are described solely for purposes of illustration and are not intended to limit the scope of the invention. Changes in form and substitution of equivalents are contemplated as circumstances may suggest or render expedient. Although specific terms have been employed herein, such terms are intended in a descriptive sense and not for purposes of limitations.
Example 1
This Example describes the production of antigen-containing starch microparticles.
A flow diagram summarising the process of starch microparticle production effected herein is shown in FIG. 1. Antigen-containing starch microparticles were manufactured by mixing starch and the antigen in solvents, forming an emulsion in oil, and then dispersing the emulsion into an acetone solution with vigorous stirring and collecting the particles formed. Starch microparticles were separately manufactured containing the antigens, human serum albumin (HSA), herpes simplex virus type 2 (HSV-2)--infected cell lysate and whole influenza virus. To form the HSV-2 and influenza virus-containing starch microparticles, HSA was included as a "filler" protein.
Specifically, 1 g of soluble potato starch was added to 2 mL of dimethylsulfoxide (DMSO) while stirring the mixture. The starch was dissolved by heating the mixture to 85° C. for 5 minutes. The following amounts (Table 1) of antigen were prepared to form the antigen-containing microparticles indicated:
TABLE 1______________________________________Antigen entrapped in starchmicroparticles Antigen Preparation______________________________________HSA 0.1 g of HSA dissolved in 1.0 mL water at room temperature.HSV-2-infected cell-lysate/HSA 25 mg of HSV-2 in 0.5 mL of buffer and 75 mg HSA in 0.5 mL H.sub.2 O.Influenza/HSA 25 mg Flu X31 in 1 mL 0.1M Tris, 5 mM EDTA pH 7.5, 75 mg HSA in 0.375 mL H.sub.2 O.______________________________________
When the starch solution had cooled to a temperature of less than 37° C., the antigen preparation indicated above was added to the cooled solution and the mixture stirred (500 rpm) at room temperature for 20 minutes to form a highly viscous mixture. This viscous mixture was added dropwise to 30.0 mL of vegetable oil and stirred vigorously (1500 rpm) for 15 minutes at room temperature to produce a water-in-oil emulsion. This water-in-oil emulsion was sonicated on ice for 60 seconds with stirring. The emulsion was then added dropwise with stirring (1000 rpm) to 400 mL of acetone containing 0,125% v/v Tween 80. The resultant particles, of approximately 4.18±3 μ were collected by centrifugation, (200 xg, 5 minutes), washed twice with acetone and dried by exposure to air at room temperature for 48 hours.
Example 2
This Example describes the coating of antigen-containing starch microparticles.
The microparticles formed in Example 1 may be coated with a variety of silicones via bonded interactions at the surface including polydimethylsiloxanes (PDMS) with different molecular weights and varied end blocks. A convenient end-functionalized silicone was 3-(triethoxysilyl)propyl-terminated polydimethylsiloxane (abbreviated to TS-PDMS).
The TS-PDMS was synthesised by the hydrosilylative addition of hydrogen-terminated PDMS to allyltriethoxysilane under the catalysis of H 2 PtCl 6 as follows. To a mixture of 17.0 mL hydrogen-terminated PDMS (Huls, PDMS H , viscosity 1,000 cs) and 0.8 mL allyltriethoxysilane (Aldrich) (molar ratio of the functional groups PDMS H : H 2 C=CH 1:3) was added 0.05 mL of a 0.1M hydrogen hexachloroplatinate(IV) hydrate solution (H 2 PtCl 6 ) in i-propanol (Caledon) with stirring under the protection of nitrogen at 0° C. The solution was allowed to return to room temperature overnight. The i-propanol and unreacted allyltriethoxysilane were evaporated under reduced pressure and elevated temperature up to 140° C. for 6 hours until gas ceased to bubble from the viscous fluid. The residue was subjected to further washing with distilled water four times to remove any impurities. The product was characterized by 1 H NMR, 29 Si NMR, GPC and IR. The reaction involved is illustrated by the following equation: ##STR1## where n is the number of siloxane groups. The use of an end-functionalized silicone resulted in the formation of chemical bonds to the starch surface.
To produce particles coated with TS-PDMS and having antigens entrapped within them, the sonicated water-in-oil emulsion produced by the procedure described above in Example 1 was added dropwise with stirring (1000 rpm) to 400 mL of acetone containing 0.125% v/v TS-PDMS (1,000 c.s.) in place of the Tween 80. The resulting coated particles were harvested and dried as described in Example 1.
Example 3
This Example describes an analysis of the antigen-containing starch microparticles.
Size distributions of the antigen-containing starch microparticles prepared as described in Examples 1 and 2 were obtained by scanning electron microscopy and flow cytometry using polystyrene microparticle standards. FIG. 2 shows a scanning electron microscope analysis of HSA-containing microparticles that were either coated with TS-PDMS or were uncoated. The microparticles ranged in size from 1 to 100 μM and had a mean diameter of 4 to 5 μM as determined by flow cytometry (FIG. 3). The efficiency of antigen incorporation into starch microparticles was between 70 and 90%.
The antigen content of HSA-loaded microparticles (termed herein "core loading") was determined by incorporating an 125 I-HSA tracer of known specific activity in the antigen preparation prior to microparticle formation. Protein core loading of HSA in starch microparticles was found to be about 5 to 6% by weight. This method of determining the "core-loading" could not be applied to whole influenza virus entrapped in microparticles because radiolabelled virus was found to be unstable. "Core-loading" of microparticles containing whole influenza virus was thus estimated by the release of virus by degradation of the microparticles by acid hydrolysis with HCl or enzymatic hydrolysis with human saliva.
Enzymatic hydrolysis of microparticles with human saliva was originally the preferred method as it was not anticipated to appreciably alter the antigenic integrity of the viral proteins. Microparticles were digested with 250 μL of centrifugally clarified saliva overnight at 37° C. Suspensions were centrifuged at 5000 xg for 10 minutes and the supernatants diluted 1:10 with Tris Base buffered saline (TBS, pH 7.2) containing 0.1% NaN 3 and stored at 4° C. until analyzed by SDS-PAGE.
"Core-loading" was determined by acid-hydrolysis of the microparticles. Thus, microparticles were incubated in 0.1M HCl for 24 hours at 37° C. Supernatants were clarified by centrifugation at 3000 rpm and filtered through a 0.45 μ filter. The solution was neutralized with 1M NaOH. Protein released from acid hydrolysed microparticles were detected using an ELISA.
The Flu X31/HSA microparticles were estimated to contain about 0.3 to 0.5% of Flu X31 and about 5 to 6% of HSA (w/w). Although HSA may be incorporated into the microparticles preferentially to Flu X31, attempts to fabricate coated microparticles without protein were unsuccessful.
Example 4
This Example describes the effects upon antigens of their entrapment in starch microparticles.
The time course samples from the antigen release studies described for HSA containing microparticles described in Example 3 were also analyzed by Western (immunoblot) analysis using an HSA-specific polyclonal antiserum. For immunodetection analysis of released HSA, the gel was equilibrated in transfer buffer (0.2M glycine, 15% methanol, 0.025M Tris Base, pH 8.3) for 15 minutes along with nitrocellulose (NC) membranes and filter paper, both of which were cut to the same size as the gel. The immunoblot apparatus was then placed in the transblot device and electrophoretic transfer was performed overnight at 30 volts. After transfer, the NC membrane was incubated with agitation in 100 mL of blocking buffer (5% w/v skim milk powder in PBS) for 2 hours. The NC membrane was then incubated with 100 mL of a 1:500 dilution of alkaline phosphatase-conjugated goat anti-HSA in blocking buffer for 2 hours at room temperature, on a tilting platform. The NC membrane was washed 3 times (10 minutes each) with PBS, and proteins were visualized by incubating the membrane with 30 mL of developing buffer (100 mM Tris Base, 100 mM NaCl, 5 mM MgCl 2 , pH 9.5) containing 200 μL of 50 mg/mL nitroblue tetrazolium and 100 μL of 50 mg/mL 5-bromo-4-chloro-3indolylphosphate for 60 minutes. The membrane was rinsed 3 times with H 2 O and air dried. The results of the immunoblot analysis are shown in FIG. 4. This analysis showed that HSA released into the supernatants by HCl treatment or incubation of the microparticles in PBS was detectable by an HSA-specific polyclonal antiserum. The released HSA from uncoated and TS-PDMS coated microparticles, was not fragmented by the fabrication process and was not altered in such a way as to preclude its detection by HSA-specific antibodies.
Example 5
This Example describes the immunogenicity of HSA entrapped in microparticles in mice immunised intraperitoneally.
To examine the immunogenicity of HSA entrapped in starch microparticles formed in accordance with the present invention, groups of six, 6 to 8 week old female BALB/c mice (Charles River Breeding Laboratories, Wilmington, Mass.) were immunized intraperitoneally (IP) with the following amounts of antigen in 250 μL of PBS (pH 7.4) on days 0, 7 and 14: 2 mg of TS-PDMS coated microparticles prepared as described in Examples 1 and 2 containing 100 μg of HSA; and 2 mg of uncoated microparticles containing 100 μg of HSA.
The mice showed no gross pathologies or behavioural changes after receiving either uncoated or TS-PDMS coated microparticles. Sera were obtained on days +21, +35, 49, +63 and +84 and were evaluated for the presence of anti-HSA IgG antibodies by antigen specific ELISA. All samples were analyzed in duplicate. Microtiter plate wells were incubated overnight at 4° C. with 100 μL of 10 μg/mL HSA in TBS. The plates were washed with Tris-T buffer (0.05% Tween 20 in 0.02M Tris Base, pH 7.4, containing 0.15M NaCl and 0.005M KCl). Wells were incubated with 200 μL of 0.1% gelatin in 0.02M Tris-buffered saline (TBS), pH 7.4 (operationally defined as blocking buffer). After washing with Tris-T, the plates were incubated for 2 h at 37° C. with 100 μL of sample serially diluted in blocking buffer. Wells were washed with Tris-T and 100 μL of alkaline phosphatase-conjugated goat anti-mouse IgG in blocking buffer, were added to each well. After 2 hours incubation at 37° C., the wells were washed with Tris-T and 100 μL of 1.0M diethanolamine buffer, pH 9.8, containing 0.05M MgCl 2 and 1.0 mg/mL of p-nitrophenylphosphate were added to each well. After 30 minutes incubation at room temperature, the optical density of the fluid in each well was determined at 405 nm using a microplate reader. A normal mouse sera pool was used to establish baseline optical density values in the assay. Hyperimmune mouse HSA antiserum was used as a positive control.
The serum antibody titres following immunization are shown in FIG. 5. The results of immunizations with a convenient test antigen (HSA) indicate that antigen presented to the immune system entrapped in TS-PDMS starch microparticles is substantially more immunogenic than soluble antigen or antigen entrapped in uncoated starch microparticles.
Example 6
This Example describes the immunogenicity of HSA entrapped in starch microparticles in mice immunized by the intragastric route.
To examine the immunogenicity of HSA entrapped in starch microparticles formed in accordance with the present invention, groups of six, 6 to 8 week old female BALB/c mice, were immunized by the intragastric route (IG) with HSA-containing microparticles, prepared as described in Examples 1 (uncoated) and 2 (coated) above, (Table II) on days 0 +7 and +14:
TABLE II______________________________________Group: Microparticle.sup.1 Type: mg particle: μg HSA:______________________________________A TS-PDMS coated 15 750B TS-PDMS coated 10 500C TS-PDMS coated 3 150D TS-PDMS coated 1.5 75E TS-PDMS coated 1 50F uncoated 15 750G uncoated 10 500H uncoated 3 150I uncoated 1.5 75J uncoated 1 50K none 0 0N none -- --O none -- 750P none -- 500Q none -- 150R none -- 75S none -- 50______________________________________ .sup.1 mg of TSPDMS coated microparticle contains 50 μg of HSA.
Sera were examined for the presence of HSA-specific antibodies on days +21, +35 and +49.
Sera and intestinal washes were examined for the presence of HSA-specific antibodies. To detect and quantify anti-HSA sIgA in the intestinal lumen, mice were sacrificed by cervical dislocation, their small intestines removed and examined for the presence of antigen-specific antibodies. Individual small intestines were detached from the pyloric sphincter to the caecum and everted over capillary tubes. The everted intestines were incubated in 5 mL of ice cold enzyme inhibitor solution (0.15M NaCl , 0.01M Na 2 HPO 4 , 0.005M EDTA, 0.002M PMSF, 0.05 U/mL Aprotinin, and 0.02% v/v NaN 3 ) for 4 hours. Intestines were removed and the supernatants clarified by centrifugation (1000 xg, 20 minutes) and stored at 0° C. until assayed. Anti-HSA sIgA titres in samples were determined by HSA-specific ELISA as described above but a goat anti-mouse IgA antiserum was used in place of the goat anti-mouse IgG antiserum.
The percentage of mice immunologically responding to the intragastric immunization is shown in FIG. 6. These results show that a much higher proportion of animals immunologically respond to the test antigen (HSA) when delivered using PDMS-coated microparticles compared to uncoated microparticles at physiologically relevant doses, for example, 75 μg or less.
The serum IgG HSA-specific antibody titres following IG immunization are shown in FIGS. 7 (50 μg of HSA) and 8 (75 μg of HSA). These results indicate that a test antigen (HSA) incorporated into PDMS-coated microparticles is substantially more immunogenic than antigen incorporated into uncoated particles when delivered by the intragastric route.
Example 7
This Example describes the immunogenicity of herpes simplex type 2 virus (HSV-2) antigens entrapped in microparticles in mice immunized by the intraperitoneal and intragastric routes.
To examine the stimulation of virus-specific immune responses by viral antigens entrapped in microparticles, mice were immunized IP and IG with HSV-2 infected cell lysates entrapped within TS-PDMS coated microparticles containing HSA as a carrier protein. Groups of 5, 6-8 week old female BALB/c mice were immunized by the intraperitoneal (IP) and intragastric (IG) routes with the following materials on days 0, +7 and +14:
1. 125 μg of HSV-2 infected cell lysate protein in 250 μL of PBS (IP) or 500 μL of NaHCO 3 (IG).
2. 16 mg of TS-PDMS coated microparticles containing about 125 μg of HSV-2 infected cell lysate.
3. 8 mg of TS-PDMS coated microparticles containing about 63 μg of HSV-2 infected cell lysate protein.
Sera were examined for the presence of HSV-2 specific IgG antibodies and demonstrated that viral proteins may be entrapped within TS-PDMS coated starch microparticles without reduction in immunogenicity.
Example 8
This Example describes the immunogenicity of whole influenza virus entrapped in microparticles in mice immunized IP.
To examine the immunogenicity of Flu X31/HSA TS-PDMS coated microparticles, prepared as described in Example 2, groups of six Balb/c mice were immunized by intraperitoneal (IP) route with the following materials:
1. 5 μg of Flu X31 and 15 μg of HSA in soluble form.
2. 5 μg of Flu X31 and 15 μg of HSA mixed with TS-PDMS coated microparticles.
3. Flu X31/HSA TS-PDMS coated microparticles containing 5 μg of Flu X31 and 15 μg of HSA.
The mice received a single immunization IP on day 0 and were bled at days +20 and +35. The sera obtained were assayed for anti-Flu X31 and anti-HSA IgG antibodies by antigen-specific ELISA. The anti-Flu X31 ELISA was performed as described above but the plates were coated overnight at 4° C. with 100 μL of whole influenza virus at 5 μg per mL in place of the HSA and an anti-Flu antibody was used as a positive control. These antibody titres are shown in FIGS. 9 and 10 for Flu X31 and HSA immunized mice respectively.
As described in Example 5 above, HSA alone or HSA mixed with TS-PDMS coated microparticles were poorly immunogenic. In contrast, HSA entrapped in TS-PDMS coated microparticles elicited high antibody titres.
Mice immunized IP with all three preparations showed similar serum IgG anti-Flu X31 antibody responses on day +20. At day +35 the IgG anti-Flu X31 antibody titre in the serum of mice immunized IP with Flu X31/HSA incorporated in TS-PDMS coated microparticles was about 10-fold greater than the titres obtained following immunization with soluble Flu X31 or Flu X31 mixed with TS-PDMS coated microparticles.
The studies presented in this Example demonstrate that viral antigens from influenza virus can be made more immunogenic and elicit high levels of serum IgG antibodies, when the antigens are entrapped in microparticles formed in accordance with the present invention.
Example 9
This Example describes the immunogenicity of whole influenza virus entrapped in microparticles in mice immunized IN.
To examine the immunogenicity of Flu X31/HSA TS-PDMS coated microparticles, prepared as described in Example 2, groups of six Balb/c mice were immunized by the intranasal (IN) route with the following materials:
1. 10 μg of Flu X31 and 30 μg of HSA in soluble
form.
2. Flu X31/HSA TS-PDMS coated microparticles containing 10 μg of Flu X31 and 30 μg of HSA.
Mice were immunized IN on days 0 +7 and +14 and bled on days +20 and +35. The sera obtained were assayed for anti-Flu X31 and anti-HSA IgG antibodies by antigen-specific ELISA as described above. These serum antibody titres are shown in FIGS. 11 and 12 for HSA and Flu X31 respectively.
Mice immunized IN with soluble antigen had undetectable levels of HSA-specific serum IgG antibodies. Mice immunized with Flu X31/HSA TS-PDMS coated microparticles showed a serum anti-HSA antibody response.
The anti-Flu X31 antibody titres in mice immunized IN are shown in FIG. 12 and show that the highest titres were obtained following immunization with Flu X31/HSA TS-PDMS coated microparticles.
The results of the IN immunizations described in this Example show that the immunogenicity of an antigen (HSA) and a mixture of influenza virus antigens can be enhanced by entrapment in microparticles formed in accordance with the present invention. In particular, the normally non-immunogenic antigen HSA following incorporation into microparticles was made immunogenic.
SUMMARY OF THE DISCLOSURE
In summary of this disclosure, the present invention provides a particulate carrier for an agent, particularly one having biological activity, comprising a core of polysaccharide and proteinaceous material and an organometallic polymer bonded to the core. The particulate carriers in the form of microparticles are able to efficiently deliver agents to the cells of the immune system of a subject following mucosal or parenteral administration to produce an immune response. Modifications are possible within the scope of this invention.
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A particulate carrier for an agent comprising a solid core of a polysaccharide and a proteinaceous material and an organometallic polymer bonded to the core is provided. The agent has a biological activity, such as immunogenicity, and may comprise the proteinaceous material or be a separate component of the core. Polysaccharide cores include dextran, starch, cellulose and derivatives thereof and the organometallic polymer includes silicones including substituted silicones. The particulate carriers are useful for delivering agents to the immune system of a subject by mucosal or parenteral administration to produce immune responses, including antibody responses.
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FIELD OF THE INVENTION
The present invention relates to a steering wheel which is capable of absorbing shock by means of bending the core metal.
BACKGROUND OF THE INVENTION
An example of conventional steering wheels is disclosed in Japanese Patent Laid-open No. 193503/1993, which comprises an annular rim portion, a boss portion located inside the ring defined by the rim portion and attached to a steering shaft, and a plurality of spokes connecting the rim portion and the boss portion, wherein the two ends of the core metal of each spoke are respectively enveloped in a die-cast metal by means of die casting and connected to the boss-core metal of the boss portion and the rim-core metal of the rim portion. However, the lower portion of the boss-side end of each spoke-core metal is not covered by the die-cast metal. The exposed part faces downward. With the configuration as above, in the event where a shock is delivered from above to the rim portion, the spoke-core metals bend, in a peeling off manner from the die-cast metal, thereby absorbing the shock.
However, the conventional configuration described above, wherein the lower part of the end of each spoke-core metal adjacent to the boss portion is exposed from the die-cast metal, causes a decrease in the resonance frequency of a steering wheel. This makes it difficult to reduce vibration of the steering wheel which results from vibration of the engine or other sources. In other words, the conventional configuration presents a problem in that it is difficult to make a steering wheel more comfortable to operate.
In order to prevent the above problems, an object of the present invention is to provide a steering wheel which has superior shock absorbing characteristics and is comfortable to operate due to reduced vibration.
SUMMARY OF THE INVENTION
A steering wheel of the present invention comprises a rim portion having a rim-core metal; a boss portion having a boss-core metal; and spoke portions having spoke-core metals for connecting together the rim-core metal and the boss-core metal, wherein each spoke portion is provided with a spoke deformation region and a raised portion formed on the spoke deformation region, the spoke deformation region being weaker than the remaining part of the spoke-core metal, and the raised portion extending in the lengthwise direction of the spoke-core metal and protruding therefrom towards the driver.
According to the configuration as above, as spoke deformation regions of spoke-core metals are reinforced under normal circumstances by raised portions, a decrease in rigidity of the wheel is prevented, and the resonance frequency of the steering wheel can easily be adjusted. In the event where a shock is delivered from the direction of the driver to the rim portion or its vicinity, tensile force is applied to the raised portions. The tensile force breaks or bends the raised portions or the end portions of the raised portions, thereby permitting the spoke-core metals to bend and absorb the shock.
A steering wheel as claimed in claim 2 of the present invention comprises a rim portion having a rim-core metal; a boss portion having a boss-core metal; and spoke portions having spoke-core metals for connecting together the rim-core metal and the boss-core metal, wherein each spoke portion has a core metal body and a reinforced portion enveloping the core metal body, and is provided with a spoke deformation region and a raised portion formed on the spoke deformation region, the spoke deformation region being weaker than the remaining part of the spoke-core metal, and the raised portion extending in the lengthwise direction of the spoke-core metal and protruding therefrom towards the driver.
According to the configuration as above, as the core metal body of each spoke-core metal is reinforced by the reinforced portion which envelopes the core metal body, decrease in rigidity of the wheel is limited, and the resonance frequency of the steering wheel can easily be adjusted. In the event where a shock is delivered from the direction of the driver to the rim portion or its vicinity, tensile force is applied to the raised portions. The tensile force breaks or bends the raised portions or the end portions of the raised portions, thereby permitting the spoke-core metals to bend and absorb the shock.
A steering wheel of the present invention further comprises a steering wheel, wherein each raised portion is formed as an integral body with a reinforced portion by means of casting.
According to the configuration as above, the raised portions can easily be formed as an integral body with the respective reinforced portions by means of casting. In cases where die-cast metal containing aluminum, magnesium or a similar metal, which is less resistance to tensile force than a compressive force, the raised portions are easily broken when a shock is delivered from the direction of the driver to the rim portion or its vicinity. As a result, the spoke-core metals bend due to the spoke deformation regions and absorb the shock effectively.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings in which like reference numerals designate the same element and the scope of the invention will be indicated in the claims.
BRIEF EXPLANATION OF THE DRAWINGS
FIG. 1 is a plane of a steering wheel according to an embodiment of the present invention.
FIG. 2 is a sectional view of same taken along the line II--II of FIG. 1.
FIG. 3 is a sectional view of same taken along the line III--III of FIG. 1.
FIG. 4 is a sectional view of same taken along the line IV--IV of FIG. 1.
FIG. 5 is a sectional view of same taken along the line V--V of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
Next, the configuration of a steering wheel according to an embodiment of the invention is explained hereunder, referring to the drawings
In FIG. 1, numeral 1 denotes a steering wheel of an automobile or the like, which is comprised of the body of the steering wheel (steering wheel body 2) and a pad 3 attached to steering wheel body 2. Steering wheel body 2 is comprised of an annular rim portion 4, a boss portion 5 located inside the ring defined by rim portion 4, and a plurality of spoke portions 6 connecting rim portion 4 and boss portion 5 together. Pad 3 is principally comprised of a cover and a shock absorber, such as an air bag apparatus provided underneath the cover. The cover covers a part of spoke portions 6 and the upper side of boss portion 5, in other words the side facing the driver. The underside of boss portion 5, i.e. the side facing the body of a vehicle, is covered by a lower cover which is not shown in the drawings. Steering wheel 1 is configured such that the plane defined by its rim portion 4 is inclined from the upper front end (the end closest to the windshield) towards the lower rear end (the end facing the driver) in the state where steering wheel 1 is attached to an automobile correctly.
As shown in FIGS. 1 to 5, steering wheel body 2 is mainly comprised of a core metal 10 and a cover portion (the outermost layer) 11 covering core metal 10 except for the part covered by pad 3. Cover portion 11 is made of a soft synthetic resin, such as urethane foam.
Core metal 10 is comprised of core metals connected to one another: a boss-core metal 12 located at boss portion 5, a total of four spoke-core metals 13,14 at spoke portions 6, and a rim-core metal 15 at rim portion 4. As shown in FIGS. 1 and 2, boss-core metal 12 consists of an essentially cylindrical steel boss 17 attached to a steering shaft (not shown), and a hub-core central area 18 which is integrally affixed to the upper portion of boss 17 with a die-cast metal by means of envelope casting. The die-cast metal for this purpose may be an aluminum alloy, magnesium alloy or the like. Further, the boss and the hub-core central area may be formed as an integral body at once or by following other procedures; for example, they may be formed by affixing a flat boss plate to the boss and enveloping the boss plate with a die-cast metal.
As shown in FIGS. 1, 3 and 4, spoke-core metals 13,14 have core metal bodies (insert spokes) 13a,14a, which are solid steel bars bent into a specified shape and enveloped by casting in reinforced portions 21,22. Reinforced portions 21,22 are integrally formed with the die-cast metal which constitutes hub-core central area 18. Rim-core metal 15 is formed from a steel pipe (a cylindrical metal pipe) which is bent into a shape of a hollow ring, with the abutted two ends welded together. Core metals 12,13,14,15 are integrally connected together, with the die-cast metal which envelopes an end of each spoke-core metal 13,14 by means of envelope casting integrally connected to hub-core central area 18 and the die-cast metal which envelopes the other end of each spoke-core metal by means of envelope casting integrally enveloping a part of rim-core metal 15. Core metals 12,13,14,15 may be connected together by welding and then by means of envelope casting.
As shown in FIGS. 1, 4 and 5, each one of the pair of rear spoke-core metals 14, i.e. those closer to the driver, is provided with a spoke deformation region 24 where the diameter of reinforced portion 22 is reduced, in other words where the die-cast metal is thinner. Each spoke deformation region 24 is located closer to boss-core metal 12 than rim portion 4. In case of the present invention, each spoke deformation region 24 extends from the end adjacent to boss-core metal 12 to the surface on which the lower cover (not shown) is attached. Furthermore, a rib-like raised portion 26 extending in the axial direction of spoke-core metal 14 and protruding upward, i. e. towards the driver, is formed along the entire length of each spoke deformation region 24. As shown in FIG. 4, each raised portion 26 is higher than reinforced portion 22 where spoke deformation region 24 is not formed so that raised portion 26 protrudes outward from the outer surface of reinforced portion 22, thereby forming a corner A at the end adjacent to boss portion 5.
In the configuration of a steering wheel 1 according to the embodiment of the invention described above, respective spoke-core metals 13,14 are not only enveloped in reinforced portions 22, which are formed of die-cast metal by means of envelope casting along the entire length of core metals 13,14, but also connected to boss-core metal 12 and rim-core metal 15 as an integral body with them. With the configuration as above, the embodiment of the invention is capable of increasing the strength (the rigidity) of steering wheel body 2 and easily increasing the resonance frequency of steering wheel 1 to a desired level. In other words, by limiting uncomfortable resonance of steering wheel 1, which is caused by vibration transmitted through the steering shaft, the invention is capable of making operation of steering wheel 1 more comfortable. Spoke-core metals 14 of spoke portions 6 which are situated in front of the driver have spoke deformation regions 24 where reinforced portions 22 are thinner. However, each spoke deformation region 24 is reinforced by a rib-like raised portion 26 formed thereon so that the strength of the steering wheel is increased, resulting in the increased resonance frequency. As each raised portion 26 protrudes in the direction opposite the direction in which steering wheel 1 vibrates, i.e. the direction represented by an arrow F in FIG. 4, it is possible to increase the section modulus of the steering wheel, thereby increasing its rigidity. As a result, the resonance frequency is effectively increased to a high level.
Spoke-core metals 14 of spoke portions 6 which are situated in front of the driver have spoke deformation regions 24 where reinforced portions 22 are thinner. Therefore, in the event of a collision or a similar accident, where the driver collides with the lower rear part of rim portion 4 of steering wheel 1, load is applied in the direction represented by arrow F in FIG. 4, elastically bending the part of core metal bodies 14a of spoke-core metals 14 where respective spoke deformation regions 24 are located. Thus, the shock of the collision is effectively absorbed.
A raised portion 26 is formed on each spoke deformation region 24 in order to increase its strength. However, raised portions 26 are formed on the side of spoke-core metals 14 facing the operator, in other words they protrude in the direction opposite the direction represented by arrow F, in which load is applied in the event of a collision. Therefore, when load is applied in the direction represented by arrow F, tensile force is applied to each raised portion 26 in the directions represented by arrows P in FIG. 4. As this tensile force breaks raised portions 26 and permits spoke-core metals 14 to bend at their spoke deformation regions 24, the shock of the collision is effectively absorbed.
Each raised portion 26 is so formed as to extend in the axial direction of spoke-core metal 14, more precisely along the entire length of spoke deformation region 24, and protrude above reinforced portion 22. Therefore, when tensile force resulting from load applied in the direction represented by arrow F is applied to each raised portion 26 in the directions represented by arrows P in FIG. 4, the stress is concentrated in corner A of raised portion 26, thereby ensuring reinforced portion 22 to break precisely at the position where corner A is located. By thus specifying the locations at which core metal 10 is deformed, the invention is capable of stabilizing shock absorbing characteristics of steering wheel 1.
In cases where an aluminum alloy is used as the die-cast metal to form raised portions 26, it is easier for a shock applied from the driver's side to break raised portions 26, thereby permitting spoke-core metals 14 to bend, because aluminum has a lower tensile than compression strength. Therefore, compared with cases where soft steel or the like is used, the shock is more effectively absorbed.
Furthermore, as spoke deformation regions 24 and raised portions 26 can easily be formed as an integral body with respective reinforced portions 22 by means of die-casting without increasing the number of parts, the invention is capable of simplifying the structure of a steering wheel and consequently reducing production costs.
According to the embodiment described above, each spoke deformation region 24 is formed by providing a thinner part of each reinforced portion 22. However, a spoke deformation region may be formed in other ways; for example by providing an opening where metal core body 14a is exposed or combining a thinner portion with an opening.
Because of the configuration wherein spoke deformation regions of spoke-core metals are reinforced under normal circumstances by raised portions, a steering wheel according to claim 1 of the present invention is capable of restricting a decrease in rigidity of the wheel and therefore the resonance frequency of the steering wheel is easily adjustable.
As vibration of the wheel is thus limited, operation of the steering wheel is made more comfortable. In the event where a shock is delivered from the direction of the driver to the rim portion or its vicinity, tensile force is applied to the raised portions. The tensile force breaks or bends the raised portions or the end portions of the raised portions, thereby permitting the spoke-core metals to bend and absorbing the shock.
Because of the configuration wherein the body of each spoke-core metal is reinforced by a reinforced portion which envelopes the core metal body, a steering wheel according to the present invention is capable of preventing decrease in rigidity of the steering wheel. Therefore, the configuration makes the resonance frequency of the steering wheel easily adjustable, thereby limiting vibration of the steering wheel. As a result, operation of the steering wheel is made more comfortable. In the event where a shock is delivered from the direction of the driver to the rim portion or its vicinity, tensile force is applied to the raised portions. The tensile force breaks the end portions of the raised portions, thereby permitting the spoke-core metals to bend due to their spoke deformation regions. Thus, the shock is absorbed.
While having the same effect as that of a steering wheel described as a preferred embodiment of this invention, a steering wheel, in another embodiment of the invention is capable of reducing production costs of a steering wheel by providing a simplified structure wherein each raised portion is formed as an integral body with a reinforced portion by means of casting. In cases where die-cast metal containing aluminum, magnesium or a similar metal which is less resistance to a tensile force that a compressive force, the raised portions are easily broken when a shock is delivered from the direction of the driver to the rim portion or its vicinity. As a result, the spoke-core metals bend due to the spoke deformation regions and effectively absorb the shock.
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A steering which reduces vibration and is shock absorbing and deformable. The steering wheel comprises a rim and a boss with a plurality of spokes, the rim, boss and spokes having a core metal. A reinforced spoke-core metal has a spoke deformation region which is a part of the reinforced portion and is thinner than the remaining part of the reinforced portion. A raised portion is included on the driver-side of each spoke deformation region which increases the strength of core metals and restricts vibration of the core metals. The configuration creates a weak point for collapsing the steering wheel in a collision and impact with the steering wheel by the driver, that is, the raised portions receives tensile forces and break, thereby smoothly bending core metal bodies.
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FIELD OF THE INVENTION
[0001] The invention relates to the field of medium and high voltage technology. It is based on an earthing switch according to the preamble of the independent claim.
BACKGROUND OF THE INVENTION
[0002] Earthing switches are used for example in switch cabinets, where the electrical circuits that are under voltage must always be earthed before the door of the switch cabinet is opened.
[0003] Such switch cabinets may for example contain components of a converter for an electrical drive. Since the voltages used are ever increasing, it is necessary that the internal electrical insulation of the earthing switches is correspondingly improved with respect to flashovers and creeping currents.
[0004] Switches of the type in question are known for example from U.S. Pat. No. 2,331,632, from U.S. Pat. No. 2,009,815 and from U.S. Pat. No. 4,263,487.
SUMMARY OF THE INVENTION
[0005] The object of the invention is to provide an earthing switch that has good electrical insulating properties.
[0006] This object is achieved by the subject matter of independent claim 1 . Further embodiments of the invention are provided by the dependent claims and the description that follows.
[0007] The invention relates an earthing switch that can be used for example for voltages of up to 15 kV (approximately 13.8 kV). The earthing switch may for example be arranged in a switch cabinet in such a way that the door of the switch cabinet can only be opened when the earthing switch has been moved into a closed position.
[0008] According to one embodiment of the invention, the earthing switch comprises a base for mounting the earthing switch, a first contact element, which is mounted on the base by way of a first insulating element, a shaft mounted in the base, a second contact element, which is mounted on the shaft and can swivel in relation to the first contact element by means of the shaft, so that the second contact element can move between a closed position and an open position, and a locking and/or monitoring device for locking the shaft and/or for monitoring the position of the shaft, which is attached to the base next to the first contact element, wherein a second insulating element is held between the base and the first insulating element and has an insulating plate that protrudes from the base and is arranged between the first contact element and the locking and/or monitoring device.
[0009] In other words, the electrical insulation between the first contact element, which is under high voltage, and the locking and/or monitoring device can be improved by the further insulating element, which provides an insulating plate between these two components, so that an already existing insulation by way of an air gap is further improved.
[0010] The base may comprise a metal plate, on which the first and/or second insulating element is mounted. The metal plate may comprise side walls, in which the shaft is held in bearings and/or on which the locking and/or monitoring device is mounted. The earthing switch can be connected to earth potential by way of the base.
[0011] It should be understood that the first insulating element and the second insulating element are generally two separate components. However, it is also possible that the first insulating element and the second insulating element are provided by one component, though the two insulating elements can be separately distinguished from one another. The first insulating element may for example comprise a body which on one side carries the first electrical contact and on the other side is connected to the second insulating element.
[0012] According to one embodiment of the invention, the second insulating element has an elongate portion, which is held between the first insulating element and the base and has first openings for mounting the second insulating element on the base and second openings for mounting the first insulating element on the second insulating element. In other words, the second insulating element may be mounted on the base, for example by means of screws, and the first insulating element may be mounted on the second insulating element, for example by means of screws.
[0013] According to one embodiment of the invention, the openings are separated from one another by webs on the elongate portion. The openings may be located on opposite sides of the elongate portion. The webs may extend substantially orthogonally in relation to the opposite sides.
[0014] According to one embodiment of the invention, a portion of the second insulating element that protrudes from the elongate portion is configured in the form of a spade, so that the insulating plate is delimited in a U-shaped manner by side walls. When considered from the side, the elongate portion and the insulating plate may run substantially parallel, the insulating plate being connected to the elongate portion for example by way of a sloping surface. The sides of the insulating plate extending away from the first contact element may be connected to side walls that provide stiffening and/or increase the insulation.
[0015] According to one embodiment of the invention, the first contact element comprises a contact shoe and the second contact element comprises a contact blade, which are inserted one into the other during the closing of the earthing switch. A contact shoe may in this case comprise one or more spring elements, between which a contact blade can be clamped. A contact blade may be an elongate, flat contact element.
[0016] According to one embodiment of the invention, the earthing switch comprises three first contact elements, which are for example arranged in a row on the base, and three second contact elements, which are for example arranged in a row on the shaft. The three first contact elements may for example be connected to a DC link of a converter, for example to its positive, negative and neutral potential. The three second contact elements may be connected in parallel (for example by way of the metallic shaft) and be connected to the earth potential (for example by way of the base).
[0017] According to one embodiment of the invention, one of the three second contact elements is provided by an L-shaped component mounted on the shaft and the remaining two second contact elements are provided by a U-shaped component mounted on the shaft. One leg of the L or the legs of the U may in this case provide a contact blade or contact blades.
[0018] According to one embodiment of the invention, the locking and/or monitoring device comprises an actuator with a locking pin, mounted on the base, and a locking disk, mounted on the shaft, the locking disk having for fixing the shaft at least one clearance in which the locking pin can engage. With this actuator it can be ensured that the earthing switch remains in a desired open position or closed position.
[0019] According to one embodiment of the invention, the actuator comprises a spring, which presses the locking pin in the direction of the locking disk, and/or the actuator of the locking device comprises an energizable coil, which when energized pulls the locking pin away from the locking disk. This coil may for example be activated by a controller when the earthing switch is to be opened or closed and/or is allowed to be opened or closed.
[0020] According to one embodiment of the invention, the locking disk has a clearance for fixing the shaft in an open position and/or a clearance for fixing the shaft in a closed position. The locking disk may be a circular disk, which has the clearances in its border. The aforementioned locking pin can engage in the clearances.
[0021] According to one embodiment of the invention, the locking and/or monitoring device comprises a plurality of switches, which are mounted on the base and mesh on a camshaft mounted on the shaft, in order to determine a position of the shaft. These switches may be activated and deactivated by a correspondingly formed camshaft (with elevations and/or depressions) when the shaft is at a specific rotational angle.
[0022] According to one embodiment of the invention, the switches and the camshaft are configured in such a way that an open position, an intermediate position and a closed position can be detected. It can be ensured in this way that at least these positions can be monitored by an external controller.
[0023] According to one embodiment of the invention, the shaft is mounted in the base by bearings (for example sliding bearings). A locking disk and/or a camshaft of the locking and/or monitoring device may be mounted on the shaft in such a way that, with respect to the bearings, it/they is/are arranged outside a portion of the shaft that carries the second contact element. For example, the locking disk and/or the camshaft may be held in a box which is mounted laterally on the base and which may for example also carry the switches.
BRIEF DESCRIPTION OF THE FIGURES
[0024] Exemplary embodiments of the invention are described in detail below with reference to the accompanying figures.
[0025] FIG. 1 shows a perspective view of an earthing switch according to one embodiment of the invention.
[0026] FIG. 2 shows a perspective view of the underside of an insulating element for an earthing switch according to one embodiment of the invention.
[0027] FIG. 3 shows a diagram with switching states of monitoring switches for an earthing switch according to one embodiment of the invention.
[0028] The designations used in the figures and their meaning are presented in a summarizing form in the list of designations. In principle, parts that are identical or similar parts are provided with the same designations.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0029] FIG. 1 shows an earthing switch 10 , which comprises a base 12 , in which three first contact elements 14 a, 14 b, 14 c are mounted. Additionally mounted on the base 12 is a shaft 16 , in which three second contact elements 18 a, 18 b, 18 c are mounted. Turning of the shaft 16 allows the second contact elements 18 a, 18 b, 18 c to be moved between an open position (shown) and a closed position.
[0030] The base 12 and/or the shaft 16 may be produced from metal or a conductive material.
[0031] Each of the first contact elements 14 a, 14 b, 14 c comprises a contact shoe 20 comprising two springs, which are connected to a contact block 22 , which is mounted on a first insulating element 24 . For this purpose, the insulating element 24 has for each contact element 14 a, 14 b, 14 c a post 26 , which keeps the contact elements 14 a, 14 b, 14 c at a distance from the base 12 .
[0032] Between the posts 26 , the first insulating element 24 may be connected directly to the base 12 and/or to a second insulating element 28 .
[0033] The second insulating element 28 has an elongate portion 30 and a spade-shaped portion 32 . The elongate portion 30 is in this case held between the first insulating element 24 and the base 12 . The elongate element extends under the three posts 26 of the first insulating element 24 and then goes over into the spade-shaped portion 32 , which extends away from the earthing switch substantially orthogonally in relation to the direction of extent of the posts 26 .
[0034] The first insulating element 24 and/or the second insulating element 28 are produced from a very poorly conducting material or insulating material, such as for instance plastic or ceramic.
[0035] The shaft 16 is mounted in two sliding bearings 34 in side walls 36 a, 36 b of the base 12 . Between the two bearings, the shaft 16 has a rectangular profile, on which the second contact elements 18 a, 18 b, 18 c are mounted. The first contact element 18 a is in this case formed as an L-shaped component, one leg providing a contact blade 38 . The contact elements 18 b and 18 c are provided by a U-shaped component, the legs of which provide two further contact blades 38 .
[0036] Mounted on the side wall 38 a and on the base 12 is a securing spring 40 , with which the shaft 16 can be kept in the open position. The securing spring 40 thereby engages in a groove in the contact element 18 a.
[0037] Additionally mounted on the side wall 38 a are a locking device and a monitoring device 44 . The spade-shaped portion 32 or its insulating plate 46 spatially separates the locking device 42 and the monitoring device 44 from the contact elements 14 a, 14 b, 14 c, so that an insulating gap is extended by the air between these components.
[0038] The locking device 42 comprises an actuator 48 in the form of an energizable coil, with which a locking disk 52 , which is located on the shaft 16 , can be prevented from rotation by means of a pin 50 (see FIG. 3 ).
[0039] The monitoring device 44 comprises a plurality of switches 54 , which mesh on a camshaft 56 and can thus provide information concerning the position of the second contact elements 18 a, 18 b, 18 c.
[0040] At the end that protrudes through the side wall 36 a, through the locking device 42 and through the monitoring device 44 , the shaft 16 has a rectangular rod 58 , onto which a key for turning the shaft 16 can be fitted.
[0041] The earthing switch 10 can be connected to a ground potential or earthing potential by way of the base 12 . The contact elements 16 a, 16 b, 16 c can also be connected to this potential by way of the shaft 16 .
[0042] The contact elements 14 a, 14 b, 14 c may be understood as the high-voltage region of the earthing switch. The contact elements 14 a, 14 b, 14 c may for example be connected to a power circuit in a switch cabinet, such as for instance the DC link of a converter, which during operation can be at a voltage of up to 15 kV (for example 6.9 kV or 13.8 kV).
[0043] For example, the contact element 14 a may be connected to a negative potential, the contact element 14 b may be connected to a neutral potential and the contact element 14 c may be connected to a positive potential of the DC link. By connecting to the contact elements 18 a, 18 b, 18 c, the DC link can then be discharged and set to ground potential.
[0044] The contact elements 18 a, 18 b, 18 c, the base 12 , the shaft 16 , the locking device 42 and the monitoring device 44 may be understood as the low-voltage region of the earthing switch 10 .
[0045] The contact elements 18 a, 18 b, 18 c, the base 12 and the shaft 16 are at ground potential. The locking device 42 and the monitoring device 44 are as a maximum at the potential of a control voltage (for example a maximum of 100 V).
[0046] The second insulating element 28 and the insulating plate 46 improve the electrical insulation between the high-voltage region and the low-voltage region.
[0047] FIG. 2 shows a perspective view of the second insulating element 28 obliquely from below.
[0048] The elongate portion 30 has a U-shaped side wall 60 , which provides a substantially cuboidal basic shape for the elongate portion 30 . On the side wall 60 there is a plate 62 , which protrudes beyond the side wall 60 , and consequently forms a peripheral border 64 . In the plate 62 are two openings 66 , which serve for mounting the first insulating element 24 on the second insulating element 28 . These openings are delimited by webs 68 , which (in the same way as the side wall 60 ) protrude orthogonally from the plate 62 . The webs 68 carry three flat portions (parallel to the plate 62 ), in which there are a further three openings 70 , by way of which the second insulating element 28 can be mounted on the base 12 . The openings 66 , 70 are spaced equally apart and/or lie on one line.
[0049] The spade-shaped portion 32 comprises the insulating plate 46 , which is connected by way of the orthogonal side wall 72 to the plate 62 , which at its end is widened in a T-like manner. The side walls 72 surround the insulating plate 46 in a U-shaped manner.
[0050] FIG. 3 shows the earthing switch 10 schematically in an open position, a half-closed position, a contacting position and a closed position (from left to right).
[0051] In the closed position and in the open position, the earthing switch 10 is kept in this position by the locking device 42 , in that the locking pin 50 engages in a respective clearance 74 in the locking disk 52 . The actuator 48 may for example comprise a coil, which when energized pulls the locking pin 50 away from the locking disk 52 , and/or comprise a spring, which presses the locking pin in the direction of the locking disk.
[0052] With the locking device 42 , the earthing switch 10 can only be actuated when the actuator 48 (or its coil) has been energized.
[0053] In the diagram, the switching state of the earthing switch 10 and of the switches 54 of the monitoring device 44 can be read off under the various positions. The shaft 16 can move in an angular range from 0° to 90°.
[0054] Between 0° (completely open position) and 74° (contacting position), the earthing switch 10 is open (“off”) and after that closed up to 90° (completely closed position) (“on”).
[0055] The cam disk 56 is designed in such a way that one or more first switches 54 between 0° and a minimum of 82° are switched off (“no”) and after that are switched on (“yes”). One or more second switches 54 are switched on between 0° and a maximum of 8° (“yes”) and after that are switched off (“no”).
[0056] For example, the coil can only be energized by way of a controller when the controller detects that at least one of the switches 54 is switched on (“yes”).
[0057] It should additionally be pointed out that “comprising” does not exclude other elements or steps and “one” or “a(n)” does not exclude more than one. Furthermore, it should be pointed out that features or steps that have been described by reference to one of the exemplary embodiments above can also be used in combination with other features or steps of other exemplary embodiments described above. Designations in the claims should not be regarded as restrictive.
LIST OF DESIGNATIONS
[0000]
10 Earthing switch
12 Base
14 a, 14 b, 14 c First contact element
16 Shaft
18 a, 18 b, 18 c Second contact element
20 Contact shoe
22 Contact block
24 First insulating element
26 Post
28 Second insulating element
30 Elongate portion
22 Spade-shaped portion
34 Sliding bearing
36 a, 36 b Side wall of the base
38 Contact blade
40 Securing spring
42 Locking device
44 Monitoring device
46 Insulating plate
28 Actuator
50 Locking pin
52 Locking disk
54 Switch
56 Camshaft
58 Rod for key
60 Side wall
62 Plate
64 Border
66 Opening
68 Web
70 Opening
72 Side wall
74 Clearance
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An earthing switch is disclosed that includes a base for mounting the earthing switch, a first contact element that is mounted on the base via a first insulating element, a shaft mounted in the base, a second contact element, mounted on the shaft, that can swivel relative to the first contact element, so that the second contact element can move between a closed and an open position, a locking and/or monitoring apparatus for locking the shaft and/or for monitoring the position of the shaft, wherein the locking and/or monitoring apparatus is fitted to the base next to the first contact element, wherein a second insulating element held between the base and the first insulating element has an insulating plate that protrudes from the base and that is arranged between the first contact element and the locking and/or monitoring apparatus.
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BACKGROUND OF THE INVENTION
[0001] The field of this invention relates to data collection regarding petroleum storage facilities. More specifically, it relates to a method and system for generating data about the amount of material being stored in petroleum storage containers.
[0002] Over a quarter of the world's energy requirements are met by petroleum products, such as petroleum, diesel, and kerosene oil. Current consumption stands at approximately $1.7 trillion U.S. dollars a year, and is increasing steadily. These substances are primarily used for motive power to run engines in vehicles including automotive cars, airplanes, ships, and locomotives. As one of the world's most valuable commodities, petroleum is traded through, large financial contracts between oil companies and suppliers, with the price of petroleum set by the prevailing market supply and demand. Due to its rather inelastic nature, demand for petroleum changes slowly and is largely impacted only by macroeconomic trends. However, supply can change drastically based on political events, production cuts, and transportation issues. As such, there is a market need for real-time information on the supply of petroleum in key markets around the world. This information typically involves tracking oil shipping tankers around the world's oceans and ports, knowing how much petroleum is flowing through key pipelines, and figuring out how much is present in storage containers. Oil tankers can be tracked through antennas at major ports, or by satellites which listen in to data transmissions from ship transponders, which identify the ship and its position. The issue of pipelines flows is still an open problem, as it's very difficult to design a non-invasive/remote sensor capable of detecting flow rates in pipelines.
[0003] Due to the geographically distributed nature of petroleum storage containers in the world and the private ownership of each container, data from the source (such as sensors placed inside each container) is not readily available. However, due to the valuable nature of the information, there have been a number of attempts to ascertain estimates of the amount of petroleum stored in containers.
[0004] There are a number of types of petroleum storage containers in use around the world used for temporary storage of crude oil and other products until they are ready to be transported further along the supply chain, or processed at a refinery. The most common type of petroleum storage container is an external floating-roof tank (EFRT), typically used to store crude oil. These tanks are vertical and cylindrical in geometry, with storage capacities of up to 1.5 million barrels of hydrocarbons and diameters in excess of 100 meters. They are constructed from steel or plastic, and have a roof which can rise or fall based on the amount of petroleum present within the tank. An internal floating-roof tank (IFRT) may be selected for greater safety, in which case the tank's floating roof is supplemented with a second roof above it, which is fixed in place. Open top tanks are seldom used due to the evaporative losses from the petroleum's volatile nature and risk of fire, while fixed-roof tanks are typically only used for products other than crude oil which have low vapor pressures. When the storage tanks are located near strategic oil pipelines, they are known as “storage hubs” or “tank farms”.
[0005] Government agencies in various countries, such as the Energy Information Agency (EIA) in the United States, release publicly available data related to petroleum storage container levels on a regular basis, but due to the time it takes to survey each individual stakeholder that provides source data, there is a delay of at least a week before it becomes available.
[0006] There have been two attempts at providing more accurate and timely data related to petroleum storage containers, both involving capturing and analysing photos of the containers. The first approach is exemplified by the strategy of Genscape, Inc., in which helicopters are employed to fly in proximity to strategic petroleum storage containers, fitted with infrared cameras that take angled shots of the oil tanks. As the petroleum inside the tanks is maintained at a different temperature than the atmosphere above the petroleum, an infrared image can identify the height of the petroleum inside the tank by means of edge detection algorithms. Given the dimensions of the tanks (often cylindrical with a known diameter), a calculation of the height multiplied by the cross-sectional area of the tank then yields the volume of petroleum stored within it.
[0007] The disadvantage of this approach is that it is extremely expensive due to the cost of the helicopter itself and insurance coverage, in addition to the wages of the pilot and the operator of the camera. Furthermore, the high cost of running the flight means that the data can only be collected at a low frequency, such as once a week—often slower than the frequency with which the storage levels change. Requiring an oblique image of the side of the tank also means that human analysis is required of the images, in order to correct for the angle of the camera and its position. As infrared cameras are often much lower resolution than optical cameras, the accuracy of such a measurement is not incredibly good.
[0008] The second approach is similar in its use of imagery, but different in its collection and analysis methods. Satellites stationed in outer space, including those in low-earth orbit and geostationary orbit, can utilize image sensors to produce approximately 1-meter resolution pictures of areas containing petroleum storage containers. As can be seen in sample images provided by DigitalGlobe, Inc., further analysis of the images is necessary to determine the amount of petroleum being stored within. If the container is an EFRT, a shadow will be cast on the top surface of the roof whenever the sun is positioned at an angle, and the tank is not completely full. Thus, by measuring the length of the shadow on the roof of such tanks, an estimate of its current storage level can be determined. However, such a measurement is both rough in its accuracy, and expensive due to the cost of launching satellites in space, which can be upwards of a million dollars. In addition, adverse weather conditions may obscure the satellite's view for days at a time, eliminating any possibility of obtaining a measurement. While such an analysis will provide data for all EFRTs in an area, it does not handle the minority of tanks which are IFRTs, and as such is incomplete in its scope.
[0009] There have been a number of previous attempts to solve some of the problems associated with remotely measuring the levels of petroleum storage tanks. For example, U.S. Pat. No. 8,842,874B1 (2010), a “Method and system for determining an amount of a liquid energy commodity stored in a particular location” mentions analyzing images of the tanks, but does not specify how one skilled in the an actually collects this data. Furthermore, image processing of storage tank data is not very accurate, nor easily automatable. Other patents, such as U.S. Ser. No. 07/664,320 (1991) provide liquid level sensors (such as float sensors) that cannot be used for remote sensing without physical access to the storage tanks themselves. Another remote-sensing technique is mentioned in application U.S. 20140363084A1, “Oil Tank Farm Storage Monitoring,” but because this relies on satellite imagery and analysis of shadows, it is unreliable and inaccurate.
BRIEF SUMMARY OF THE INVENTION
[0010] The foregoing and other features and advantages of preferred embodiments of the present invention will be more readily apparent from the following detailed description. The detailed description proceeds with references to the accompanying drawings.
[0011] The features and advantages described in the specification are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter.
[0012] This invention makes use of an unmanned aerial vehicle (UAV), colloquially known as a drone, for collecting data about petroleum storage containers in a manner that is cost-effective and extremely accurate. The UAV is flown directly above, or in proximity to each petroleum storage container that is intended to be measured. As it flies, the UAV collects data from onboard distance sensors which are then processed and analyzed by an algorithm to determine the amount of petroleum present in each storage container. This result is then transmitted over a network such as the Internet for further distribution, via e-mail, a real-time feed, a mobile application, or publishing on the World Wide Web.
[0013] The foregoing and other features and advantages of preferred embodiments of the present invention will be more readily apparent from the following detailed description. The detailed description proceeds with references to the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0014] Preferred embodiments of the present invention are described with reference to the following drawings, wherein:
[0015] FIG. 1 is a diagram illustrating an exemplary UAV measurement system;
[0016] FIG. 2 is a diagram illustrating a quadcopter flying overhead petroleum storage containers, measuring the distance to each container's roof;
[0017] FIG. 3 is a diagram illustrating a fixed-wing aircraft flying overhead petroleum storage containers, measuring the distance to each container's roof;
[0018] FIG. 4 is a diagram illustrating the flight of a UAV in a pre-programmed flight path overhead a. multitude of petroleum storage containers;
[0019] FIG. 5 is a diagram illustrating a UAV positioned at an oblique angle to a petroleum storage container with an infrared image sensor;
[0020] FIG. 6 is a flowchart illustrating an algorithm for determining the amount of petroleum being stored within one or more storage containers;
[0021] FIG. 7 is a diagram illustrating the distances from the ground to the roof of the tank, the lip of the tank, the bottom of the UAV, and from the UAV to the top of the tank.
DETAILED DESCRIPTION OF THE INVENTION
[0022] A preferred embodiment of the present invention is now described with reference to the figures where like reference numbers indicate Identical or functionally-similar elements. Reference in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[0023] In addition, the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
[0024] Certain aspects of the present invention include process steps and instructions described herein in the form of an algorithm. It should be noted that the process steps and instructions of the present invention could be embodied in software, firmware, or hardware, and when embodied in software, could be downloaded to reside on and be operated from different apparatuses used by a variety of operating systems.
[0025] FIG 1 . is a block diagram representing an exemplary measurement system. It is composed of the UAV 1 , which includes, but is not limited to, unmanned multi-rotor craft, helicopters, quadcopters, fixed-wing airplanes, lighter-than-air craft, and tethered aerostats. The UAV 1 includes a plurality of sensors, including, but not limited to, a Global Positioning System (GPS) sensor, a laser distance meter (colloquially known as a laser rangefinder), a laser distance and ranging (LIDAR) sensor, an ultrasonic distance meter, an optical image sensor (camera), a stereo optical image sensor (stereo vision camera), a radio distance and ranging (RADAR) sensor, an infrared image sensor (infrared camera), or a millimeter-wave sensor (not illustrated). The UAV 1 also includes one or more batteries or capacitors, including, but not limited to, lithium-ion batteries, nickel-cadmium, batteries, and other electrical energy storage devices (not illustrated). In addition, the UAV 1 includes an onboard flight computer (not illustrated). The communications link 8 includes, but is not limited to, the Internet, an intranet, a wired Local Area Network (LAN), a wireless LAN (WLAN), a Wide Area Network (WAN), a Metropolitan Area Network (MAN), the Public Switched Telephone Network (PSTN), and other types of communications providing voice, video, or data communications. The short-range communications link 6 includes, but is not limited to, radio, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, Bluetooth, microwave, and other types of direct point-to-point communication links. The communications links 6 , 8 may also include one or more servers or access points (AP) including wired and wireless access points (WAP) (not illustrated). The petroleum storage tank 2 includes, but is not limited to, external floating-roof tanks, internal floating-roof tanks, open top tanks, fixed-roof tanks, and closed floating-roof tanks of any geometry. The computers 3 , 4 include, but are not limited to, desktop computers, laptop computers, cloud computers, tablet computers, smartphones, headless computers, and other devices with central processing units (CPUs). In one embodiment, the computers 3 process data from the UAV before transmitting it over the network 7 . In another embodiment, the flight computer on board the UAV 1 sends the data directly to the computers 4 for further processing. The UAV may include commercially-available products including the DJI Phantom, the Parrot AR, or the 3DR Solo. The aforementioned batteries in the UAV 1 typically have a lifetime of approximately fifteen minutes. For this application, however, because petroleum storage containers are typically grouped together geographically in a small area of a few square kilometers, the UAV 1 can easily fly over most of the storage containers in a single flight. To cover multiple areas of petroleum storage containers, multiple UAVs can be operated in parallel.
[0026] FIG 2 . is a block diagram representing a measurement technique of the invention. In this particular embodiment, the UAV 1 contains a distance meter, including, but not limited to, a laser distance meter, or an ultrasonic distance meter, which transmits a signal 10 in the direction of the petroleum storage container 2 , such that a reflection of the signal 11 is received back at the UAV 1 . By using time-of-flight (TOF) techniques, the distance to the container 2 can be determined by dividing the duration of the flight of she signal by the speed of the transmitting medium (for example, the speed of light). This measurement can then be transmitted to the computer 9 wirelessly.
[0027] FIG 3 . is a block diagram illustrating an alternate embodiment of the invention, in which the UAV 1 is a fixed-wing airplane. The UAV 1 contains a distance meter, including, but not limited to, a laser distance meter, or an ultrasonic distance meter, which transmits a signal 13 in the direction of the petroleum storage container 2 , such that a reflection of the signal 12 is received back at the UAV 1 . By using time-of-flight (TOF) techniques, the distance to the container 2 can be determined by dividing the duration of the flight of the signal by the speed of the transmitting medium (for example, the speed of light). This measurement can then be transmitted to the computer 14 wirelessly.
[0028] FIG 4 . is a block diagram illustrating the UAV 1 following a pre-programmed flight path 15 over a multitude of petroleum storage containers 2 . Due to the difficulty of flying the UAV remotely, computer algorithms are typically used to program the flight path in advance, to ensure an accurate flight and to free the human operator from struggling with the controls. These take the form of a feedback loop, with inputs of the expected position of the craft at that point in time as well as its current position and speed from the GPS sensor onboard, and outputs being the power provided to each motor of the craft and any positions of the flaps. This ends up not only reducing the cost of flight, but ensures a repeatable process for collecting data. The measurement data as well as the telemetry data necessary for the autopilot is transferred to and from the UAV 1 over the wireless link 8 .
[0029] FIG 5 . is a block diagram illustrating an alternate embodiment of the invention, in which the UAV 1 is outfitted with an infrared image sensor and positioned at an angle to the petroleum storage container 2 , which is art internal floating-roof tank (IFRT). Light rays 16 from the container 2 are reflected off the surface and forms an image at the focal point of the camera on the UAV 1 . These images may then be transmitted over a wireless link 8 for further processing to a computer (not illustrated).
[0030] FIG. 7 . is a block diagram illustrating the relevant distances used in the calculation of the amount of petroleum stored in the storage containers 2 as measured by the UAV 1 . D 1 is the distance from ground level up to the top of the floating roof of the container 2 . D 2 is the distance from ground level up to the top lip of the container 2 , which is also its maximum height. D 3 is the distance from ground level up to the bottom of the UAV 1 . D 4 is the distance from the bottom of the UAV 1 to the top of the floating roof of the container 2 .
[0031] FIG 6 . is a flowchart illustrating the algorithm processed in order to determine the amount of petroleum stored in one or more storage containers 2 . The UAV 1 flies either directly overhead or in proximity to each storage container intended to be measured 2 . The UAV 1 is outfitted with a GPS sensor (not illustrated) in order to guide it to the correct position in proximity to each storage container 2 , and single or multiple sensors (not illustrated) are utilized to determine the amount of petroleum stored in each container.
[0032] Depending on the type of the storage container being measured, one or more of the aforementioned sensors will be positioned at the bottom of the UAV and pointed in the direction of the storage container during its flight. We begin the algorithm at 17 , and initialize a variable storing the total sum of petroleum to 0. The first step 18 is to evaluate whether the tank is an external or internal floating-roof tank. In the case of measuring an EFRT, the UAV is fitted with a distance meter of some type; this may be any of the previously mentioned sensors, such as laser or ultrasonic meters. For IFRTs, the UAV is fitted with an infrared image sensor or millimeter-wave sensor in order to see the liquid level of a tank.
[0033] The next step 19 for an EFRT is to measure the distance from the bottom of the UAV to the top of the floating-roof tank. In the case of distance sensors, because the altitude of the craft 1 above
[0034] ground-level is known to within a centimeter (in the case of real-time kinematic GPS), the distance measured when the craft is positioned overhead the EFRT is a proxy for the height of the roof within the tank 2 . In practice, multiple readings from the sensors will be taken within a quick interval and subsequent statistical operations may be applied, such as averaging or noise filtering. Next, the result of step 19 is subtracted from the measured height of the UAV 1 to produce the height of the roof above ground level, 20 . As the roof of the EFRT 2 rises and falls with the level of the petroleum inside the container, knowing the height of the roof allows a calculation of the total volume being stored in the tank. To do this, a measurement or lookup operation 21 is performed (in the case of existing knowledge on the Internet or in a database) to ascertain the dimensions and geometry of the tank. If such knowledge is not available, the data from the distance meter and/or image sensor can be used to establish the dimensions and geometry of the tank. The amount of petroleum then stored in the tank 2 is established in step 22 by multiplying the height obtained in 20 by the cross-sectional area of the tank 2 established in step 21 . For example, as almost all EFRTs are cylindrical in geometry, the equation for calculating the volume stored within it is =(pi*radiuŝ2)*(height of floating roof).
[0035] In the case of an IFRT, the algorithm proceeds along an alternate branch after step 18 . At least one image is taken in step 24 of the IFRT 2 from the UAV 1 with the camera positioned at an angle, such that the side profile of the IFRT is visible to the camera. The distance meter on the UAV 1 is then utilized to measure the distance from the UAV 1 to the top of the IFRT's 2 fixed roof. At step 26 , the result of step 25 is subtracted from the measured height of the UAV 1 . to produce the height of the roof above ground level. Next, at step 27 , a measurement or lookup operation is performed (in the case of existing knowledge on the Internet or in a database) to ascertain the dimensions and geometry of the tank. If such knowledge is not available, the data from the distance meter and/or image sensor can be used to establish the dimensions and geometry of the tank. By knowing the true height of the tank 26 and using computer vision algorithms to edge detection on the image obtained in 24 , one skilled in the art can determine the percent height of the floating-roof by dividing the y-coordinate of the edge (in pixels) by the total height of the tank 2 (in pixels). Once this has been determined, multiplying that percent by the number established in 26 provides the height of the IFRT's 2 internal floating-roof tank, 28 . The amount of petroleum then stored in the tank 2 is established in step 29 by multiplying the height obtained in 28 by the cross-sectional area of the tank 2 established in step 27 . For example, as almost all IFRTs are cylindrical in geometry, the equation for calculating the volume stored within it is =(pi*radiuŝ2)*(height of floating roof).
[0036] In step 31 , the individual amounts of petroleum in each container are added to the running subtotal, representing the amount of petroleum stored in all storage containers thus far processed. Once data for all the storage containers has been measured and processed, the while loop 30 breaks, and the algorithm proceeds to return the subtotal from step 23 as the final result. This result may then stored in a database along with a timestamp for historical analysis, and distributed on the Internet for sale to interested parties.
[0037] Preferred embodiments of the present invention includes network devices and interfaces that are compliant with all or part of standards proposed by the Institute of Electrical and Electronic Engineers (IEEE), International Telecommunications Union-Telecommunication Standardization Sector (ITU), European Telecommunications Standards Institute (ETSI), Internet Engineering Task Force (IETF), U.S. National Institute of Security Technology (NIST), American National Standard Institute (ANSI), Wireless Application Protocol (WAP) Forum, Bluetooth Forum, or the ADSL Forum. However, network devices and communication links based on other standards could also be used.
[0038] An operating environment for devices of the present invention include a processing system with one or more high speed Central Processing Unit(s) (CPU) or other types of processors and a memory. In accordance with the practices of persons skilled in the art of computer programming, the present invention is described below with reference to acts and symbolic representations of operations or instructions that are performed by the processing system, unless indicated otherwise. Such acts and operations or instructions are referred to as being “computer-executed,” “CPU executed” or “processor executed.”
[0039] It will be appreciated that acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. An electrical system represents data bits which cause a resulting transformation or reduction of the electrical signals, and the maintenance of data bits at memory locations in a memory system to thereby reconfigure or otherwise alter the CPU's operation, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical magnetic, optical, or organic properties corresponding to the data bits.
[0040] The data bits may also be maintained on a computer readable medium including magnetic disks, optical disks, organic memory, and any other volatile (e.g., Random Access Memory (RAM)) or non-volatile (e.g., Read-Only Memory (ROM)) mass storage system readable by the CPU. The computer readable medium includes cooperating or interconnected computer readable medium, which exist exclusively on the processing system or be distributed among multiple interconnected processing systems that may be local or remote to the processing system.
[0041] Although the present invention has been described above with respect to several embodiments, various modifications can be made within the scope of the present invention. For example, the steps of the flow diagrams may be taken in sequences other than those described, and more or fewer elements may be used in the block diagrams. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.
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A system and method for determining the amount of petroleum present in petroleum storage containers, by means of an unmanned aerial vehicle flying in proximity to said containers and collecting data. This data includes position and distance measurements in relation to the unmanned aerial vehicle and storage containers which allow a calculation of the amount of petroleum contained within the containers.
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IDENTIFICATION OF RELATED APPLICATIONS
This patent application is a continuation of and claims priority benefit from U.S. patent application Ser. No. 10/775,467, filed on Feb. 10, 2004 now pending, entitled “Dispensing System for Print Media Having Differential Perforation Pattern,” which is a divisional application of U.S. patent application Ser. No. 10/037,824, filed on Nov. 9, 2001, now U.S. Pat. No. 6,696,127, issued Feb. 24, 2004, entitled “Differential Perforation Pattern for Dispensing Print Media,” which in turn claims priority benefit from U.S. Provisional Application No. 60/248,143, filed on Nov. 13, 2000, all of which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
Perforations provide a mechanism for dividing a web of print media into individually dispensable sheets.
Relevant printing systems dispense individually printed sheets from a continuous web of print media. The individual sheets can be dispensed to recipients by automated cutting or manual tearing of the sheets from the web. However, automated cutting adds mechanical complexity, imposes servicing requirements, and subjects printing systems to mechanical breakdown. Manual tearing shifts some of this burden onto recipients for carrying out the necessary operations. In addition, tearing can produce ragged edges and disturb registration of the print media within the printer.
Perforations have been used to assist tearing along designated lines. However, the amount of force required to tear even perforated lines can vary widely depending upon the direction and position at which the tear forces are applied. Braking mechanisms, which add problems similar to those of automated cutting mechanisms, are sometimes needed to maintain proper registration of the print media within the printers.
So-called “slits” separated by uncut portions referred to as “ties” form the perforated lines, which can extend from one edge to another through a center of the web. Tearing is accomplished most efficiently by applying tensile forces in offset positions that concentrate the tensile forces through one tie at a time. As each tie breaks, the tensile forces shift to the next adjacent tie. Ordinarily, such tearing starts by breaking ties near one edge of the web and proceeds by breaking ties in succession through the center to the other edge of the web.
Other more centered positions for applying tensile forces can distribute the tensile forces through more than one tie at a time. Bursting is accomplished by breaking at least some or all of the ties between both edges of the web at once. The tensile forces required to break all of the ties simultaneously are much higher than those required to break the same ties in succession. Breaking a smaller grouping of the ties simultaneously requires tensile forces intermediate to those required for breaking the ties individually or all at once.
Such wide variability in the tensile forces required to manually separate individual printed sheets along lines of perforation also requires a corresponding capacity for high braking forces and imposes inconsistent demands on recipients to perform the tearing operation. The tensile forces required for bursting all of the ties or even some groupings of the ties can easily exceed reasonable levels for performing manual operations of this sort.
One solution is to weaken the ties to reduce the maximum tensile force required to burst the ties simultaneously. However, the weakened ties also lower the minimum tensile forces required to tear the ties in succession. Such weakened webs are subject to breakage during in-line manufacture, loading into the printer, and subsequent feeding through the printer.
SUMMARY OF THE INVENTION
My invention improves the dispensing of perforated sheets from printers and other dispensing devices by reducing variability among tensile forces required to separate the perforated sheets from webs throughout a range of positions at which the tensile forces can be applied. Initiating tearing actions along lines of perforations at one edge or the other of the webs is made relatively more difficult, while initially bursting ties located near the centers of the webs is made relatively easier. For example, perforation patterns can be arranged in accordance with my invention to support a controlled bursting sequence in which ties break in pairs, starting at the web center and proceeding simultaneously toward both edges.
Ordinarily, the minimum tensile forces required to tear lines of perforation are applied from offset positions that initially stress and break the ties located along one of the web edges and proceed by stressing and breaking the remaining ties one at a time. My invention can sustain or even enlarge these minimum tensile forces by maintaining or increasing the strength of ties located near the opposite edges of the webs.
The maximum tensile forces ordinarily required to tear lines of perforation are applied through all of the ties at once. My invention reduces the maximum tensile forces by weakening the ties located at or near the centers of the webs so that these ties break in advance of the rest. Due to the flexible nature of webs, tensile forces applied from the same centered positions stress and break the next adjacent ties paired on opposite sides of the web centers. The remaining ties paired on opposite sides of the web centers are stressed and broken in succession. Thus, even where tensile forces are applied in a manner that initially stresses all of the ties, the ties are still broken in a sequence that greatly reduces the maximum tensile forces.
One example of my new in-line supply of print media is arranged as a web of printable media having regularly spaced lines of perforation that separate the web into individually dispensable sheets. The lines of perforation extend transversely with respect to a longitudinal dimension of the web crossing a longitudinal centerline between two edges of the web. A pattern of ties separated by slits extend along the lines of perforation. The ties occupy a larger portion of the lines of perforation adjacent to the edges of the web than adjacent to the centerline of the web sufficient to relatively increase resistance to tearing near either of the two edges while relatively decreasing resistance to tearing starting near the centerline of the web.
Preferably, the ties located closest to the centerline of the web are weaker than the ties located closest to the edges of the web along the lines of perforation. In addition, the ties are preferably unevenly spaced along the lines of perforation with enlarged spacings separating the ties located closest to the centerline of the web from the remaining ties located closer to the two edges of the web. Once the weaker ties located closest to the centerline of the web have burst, the enlarged spacings encourage the web to pucker, thereby allowing the remaining stronger ties to break in succession from both sides of the web centerline.
The print media itself is preferably made of a flexible non-elastic material. The flexibility permits puckering, while the non-elasticity permits the concentration of tensile forces through limited numbers of ties. Each of the sheets of print media can be individually printed by the printer prior to being dispensed from the printer. One example is a thermal paper having a surface coated with a thermosensitive material that forms images in response to the application of heat in patterns. Tensile forces applied along the centerline of the web between adjacent sheets rupture the ties along the intervening line of perforation in a sequence starting with the ties located closest to the centerline of the web and proceeding in opposite directions through the remaining ties located closer to the two edges of the web. Alternatively, tensile forces applied along either edge of the web can rupture the ties in a more usual sequence starting at one edge and proceeding tie-by-tie to the other edge. However, regardless of where the tensile forces are applied between the edges of the web, comparable tensile forces are required to separate the printed sheets from the web.
DESCRIPTION OF THE DRAWINGS
FIG. 1 diagrams my printing system tracing a pathway for printing and dispensing sheets from a fan-folded web of print media.
FIG. 2 illustrates two of the sheets in the form of scrip broken away from the web and divided from each other by a line of perforation that is enlarged to more clearly show a modified pattern of ties and slits.
FIGS. 3A–3D depicts an expected sequence of tearing actions between the two sheets of scrip associated with tensile forces applied along a longitudinal centerline of the web.
FIGS. 4A–4D depicts another sequence of tearing actions between the two sheets of scrip associated with tensile forces applied along an edge of the web.
FIG. 5 diagrams an in-line system for making the web of print media with lines of perforation dividing the web into separately dispensable sheets.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An exemplary printing/dispensing system 10 depicted in FIG. 1 dispenses sheets 12 from a web of print media 14 arranged in a fan-folded stack 16 . The web of print media 14 advances through a printer 20 that pinches the web 14 between a print head 22 and a drive platen 24 . Friction generated by this pinching action represented by arrows 26 imparts either a driving force or a braking force on the web 14 for preserving a desired registration of the web 14 with the print head 22 .
The printer 20 is preferably a thermal printer under control of a processor 30 . The web of print media 14 is preferably a thermal paper having a thermosensitive coating 32 on a surface adjacent to the print head 22 . Heat applied in patterns by the print head 22 produces images in the thermosensitive coating 32 . Alternatively, ink jet paper or other printable media separable along lines of perforation could also be used in connection with an ink jet or other print-on-demand printer. The printed images can be unique to the individual sheets 12 and related by the processor 30 to local or remote events.
Although shown in a fan-folded stack 16 , the web 14 could also be arranged in a roll or other form for supplying an unbroken stream of the sheets 12 . Other printers, including ink jet and laser printers, could also be used with different webs of compatible print media. A separate braking mechanism under the control of the processor 30 could also be used to augment or replace the braking interface of the print head 22 and platen 24 .
In the enlarged view of FIG. 2 , the sheets 12 , which are depicted as sheets 12 A and 12 B of scrip, are separated from each other along the web 14 by lines of perforation 36 that extend transversely with respect to a longitudinal dimension of the web, crossing a longitudinal centerline 38 between two edges 40 and 42 of the web 14 . The scrip sheets 12 A and 12 B are preprinted with repeating indicia 44 and 46 , but also contain unique information 48 added by the printer 20 . For example, the printer 20 can print dollar amounts on the scrip sheets 12 A and 12 B in accordance with instructions from the processor 30 .
The lines of perforation 36 contain ties 50 , 52 , 54 , 56 , 58 , and 60 separated by slits 62 , 64 , 66 , 68 , and 70 . Additional slits 72 and 74 separate the ties 50 and 60 from the two edges 40 and 42 of the web 14 to resist any tendency to scallop the edges 40 and 42 during separation of the sheets 12 A and 12 B. The ties 54 and 56 located closest to the centerline 38 of the web 14 are thinner or otherwise weaker than the remaining ties 50 , 52 , 58 , and 60 located closer to the two edges 40 and 42 of the web 14 . For example, the ties 54 and 56 have a width dimension “T1” that is thinner than a width dimension “T2” of the ties 50 , 52 , 58 , and 60 . In addition, the ties 54 and 56 are separated from their next closest ties 52 and 58 by slits 64 and 68 that have a width dimension “S” that is much greater that the unlabeled width dimensions of the remaining slits 62 , 66 , 70 , 72 and 74 .
After printing, the web 14 is advanced past a burster bar 76 (shown in FIG. 1 ) into a position at which the closest line of perforation 36 overlies the burster bar 76 . Tensile forces 78 applied manually to the scrip sheet 12 A along the centerline 38 , as also shown in the sequence of drawing FIGS. 3A–3D , are opposed by braking forces applied by the printer 20 to the scrip sheet 12 B lying between the closest line of perforation 36 and the remaining portion of the web 14 . The burster bar 76 provides an edge that concentrates a component of the tensile forces 78 normal to the lines of perforation 36 .
The ties 54 and 56 closest to the centerline 36 (see also FIG. 2 ) are preferably stressed at least as much as the other ties 50 , 52 , 58 , and 60 located closer to the two edges 40 and 42 of the web and are weaker than the other ties (e.g., by at least 20 percent). As a result, the ties 54 and 56 tend to rupture (break) in advance of the other ties 50 , 52 , 58 , and 60 as shown in FIG. 3B . The partly separated web 14 is flexible yet sufficiently inelastic to transfer the tensile forces 78 around the extra wide span of the slits 64 and 68 to the next closest ties 52 and 58 .
A puckering action through the span of the extra wide slits 64 and 68 distorts the web 14 from a planar form and concentrates the tensile forces 78 through the next closest ties 52 and 58 , thereby rupturing these ties as shown in FIG. 3C and transferring the tensile forces 78 to the last remaining ties 50 and 60 located closest to the web edges 40 and 42 . An expanded puckering action concentrates the tensile forces 78 through these remaining ties 50 and 60 , resulting in their rupture and a complete separation of scrip sheet 12 A from the scrip sheet 12 B as shown in FIG. 3D .
Although all of the ties 50 , 52 , 54 , 56 , 58 , and 60 can be initially stressed by the tensile forces 78 applied along the centerline 38 , the relative weakening of the centermost ties 54 and 56 together with a controlled distortion of the web 14 permits the tensile forces 78 to break the remaining ties in a succession of tie pairs 54 and 56 , 52 and 58 , and 50 and 60 . The breakage of the ties 50 , 52 , 54 , 56 , 58 , and 60 in the prescribed succession significantly reduces the overall magnitude of the tensile forces 78 required to separate the scrip sheet 12 A from the remaining portion of the web 14 with respect to the overall magnitude of the tensile forces required to achieve the same objective by breaking all of the ties 50 , 52 , 54 , 56 , 58 , and 60 at once.
The overall magnitude of the tensile forces 78 is comparable to the overall magnitude of tensile forces 80 applied manually along the edge 40 of the web for rupturing the ties 50 , 52 , 54 , 56 , 58 , and 60 according to a more conventional tearing action depicted in the drawing FIGS. 4A–4D . Here, the tearing begins at the tie 50 located closest to the edge 40 and proceeds one-by-one through the remaining ties in their listed order 52 , 54 , 56 , 58 , and 60 without regard to the relative strengths of the ties. In fact, the relatively weakened ties 54 and 56 have little or no effect on the overall magnitude of the tensile forces 80 because the relatively stronger ties 50 , 52 , 58 , and 60 are also separately broken in the same sequence. Similar results can be expected for tensile forces applied along the opposite edge 42 .
Thus, the tensile forces 78 applied along the centerline 38 , which would otherwise be unacceptably high, are significantly reduced; and the tensile forces 80 applied along either of the edges 40 or 42 , which are ordinarily much lower, are substantially maintained. The similarity of the overall magnitudes of the tensile forces 78 and 80 without regard to the positions at which these forces are applied between the edges 40 and 42 allows the script sheet 12 A to be gripped through the same range of positions and separated from the remaining portion of the web 14 by a more consistent and predictable exertion of manual force.
Many other combinations and patterns of ties and slits following these general practices can be arranged to achieve similar goals. For example, more or less ties can be used. The ties could also be made progressively stronger approaching both edges 40 and 42 of the web to further promote a controlled bursting sequence starting near the centerline 38 and proceeding towards both edges 40 and 42 . Relatively strengthening the ties 50 and 60 closest to the edges 40 and 42 of the web 14 can be used to relatively increase resistance to tearing actions starting at either edge 40 or 42 without unduly increasing resistance to tearing starting near the centerline 38 .
The web 14 of print media is preferably manufactured by an inline press 84 such as shown in FIG. 5 . A roll 86 unwinds the web 14 of print media into the press 84 for a sequence of processing operations. A printing station 88 , which is representative of a plurality of printing and surface treating stations, applies the repeating indicia 44 and 46 to the web 14 . A die cutting station 90 cuts the lines of perforation 36 into the web 14 at regularly spaced intervals in registration with the printing operations for dividing the web into the individually dispensable sheets 12 . A folding station 92 folds the web into the fan-folded stack 16 that can be inserted into the printing/dispensing system shown in FIG. 1 .
Additional or replacement operations can be performed along the in-line press for adapting the sheets 12 for a variety of purposes, including couponing and labeling. During manufacture, the webs can contain more than one width of the sheets 12 and can be longitudinally sliced into multiple webs of dispensable sheets. The printing operations are preferably performed flexographically; but other in-line printing processes can also be used, such as variable imaging, letterpress, rotogravure, and screen printing. The web of print media 14 is preferably a thermal paper, but other paper or media products, such as conventional bonded or ink jet paper, having the requisite flexibility and inelasticity can also be used. The in-line press operations can be performed on a single press, or the operations can be divided among a plurality of presses. For example, the printing operations can be performed on one press, and the perforating and folding functions can be performed on another press. Registration marks printed on the webs can be used to synchronize the presses.
The web of print media 14 can be printed in advance of being mounted in the dispensing system 10 or can be printed just prior to dispensing. Examples of such dispensable print media include tags, tickets, coupons, and labels. For most such uses, at least some printing is preferably completed before the media is loaded into the dispensing system 10 . Links between the processor 30 and internal or external information systems can be established to print unique information on the sheets 12 within the dispensing system 10 prior to the intended separation of the sheets 12 from the remaining print media 14 . In place of a printer within the dispensing system 10 , a stand-alone braking mechanism can be used to prevent the sheets from being prematurely dispensed before the sheets have been separated from the web 14 along the lines of perforation 36 .
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A web of print media dispensable as individual sheets along lines of perforation includes a pattern of ties and slits that provide a more predictable resistance to manually separating the sheets from the web. The lines of perforation extend transversely with respect to a longitudinal dimension of the web and cross a longitudinal centerline between two edges of the web. The ties are weaker near the centerline of the web than near either of the two edges sufficient to relatively increase resistance to tearing along the lines of perforation starting near either of the two edges while relatively decreasing resistance to tearing along the same lines of perforation starting near the centerline of the web.
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BACKGROUND OF THE INVENTION
[0001] Most DC to DC switching voltage regulators such as the Buck converter and boost converter are capable of only regulating a voltage above or below a given input but not capable of both step up and step down regulation. A SEPIC (single ended primary inductor converter) is a DC-DC converter which allows the output voltage to be greater than, less than, or equal to the input voltage. The output voltage of the SEPIC is controlled by the duty cycle of the control transistor. The largest advantage of a SEPIC over the buck-boost converter is a non-inverted output (positive voltage). SEPICs are useful in applications where the battery voltage can be above and below the regulator output voltage. For example, a single Lithium ion battery typically has an output voltage ranging from 4.2 Volts to 3 Volts. If the accompanying device requires 3.3 Volts, then the SEPIC would be effective since the battery voltage can be both above and below the regulator output voltage. Other advantages of SEPICs are input/output isolation and true shutdown mode: when the switch is turned off output drops to 0 V.
[0002] As shown in FIG. 1 a prior art SEPIC converter 1 comprises a PWM control circuit 2 , N-channel power MOSFET 3 with intrinsic drain-to-source diode 4 , high-side inductor 5 , capacitor 6 , low-side inductor 7 , rectifier diode 8 and output capacitor 9 powering load 10 . Operation comprises repeatedly magnetizing inductor 5 whenever MOSFET 3 is in its ON and conducting state and transferring energy to output capacitor 9 and load 10 in alternating phases.
[0003] During operation, the node voltage Vx peaks at a voltage (V IN+V OUT ). The BV DSS breakdown of MOSFET 3 and diode 4 must exceed this peak voltage with some reserve.
[0004] The converter as shown cannot survive an over-voltage condition because no means exists to stop the switching operation of MOSFET 3 . Instead of limiting the maximum input voltage, converter 1 continues to operate at any input voltage until the drain voltage on MOSFET 3 exceeds safe limits and damages the device. In addition to this inability to survive high input voltages, PWM controller 2 contains low-voltage control circuitry which cannot operate when powered directly from a high voltage input.
[0005] The circuit as shown also suffers from the lack of a true load disconnect. Current sensing is also problematic since there is no convenient means to detect the input current in inductor 5 .
[0006] What is needed is a SEPIC converter offering high-voltage operation up to some safe level below the rating of the power MOSFET, a means to inhibit switching operation under excessive input voltage conditions, the ability to disconnect the load from the input, and a means to detect the input current either to implement current mode control, to prevent over-current conditions, or ideally both.
SUMMARY OF THE INVENTION
[0007] The present invention provides a family of SEPIC converters that overcome the disadvantages of the prior art. A basic building block of this family is the generic SEPIC converter shown in FIG. 1 . This converter includes a high-side inductor that connects a node V w to a node V x . The node V x is connected, in turn to ground by a power MOSFET. The node V x is also connected to a node V y by a first capacitor. The node V y is connected to ground by a low-side inductor. A rectifier diode further connects the node V y and a node V out and an output capacitor is connected between the node V out and ground.
[0008] A PWM control circuit is connected to drive the power MOSFET. The PWM control circuit turns the power MOSFET ON an OFF in a repeating pulse-width-modulation pattern. The duty cycle of the power MOSFET is varied in proportion to the voltage at the node V out to maintain the output of the SEPIC converter within regulation. Whenever the power MOSFET is ON, current from the input supply magnetizes the high-side inductor. When the power MOSFET subsequently turns OFF, the energy stored in the magnetic field of the inductor is transferred to the output capacitor. A load connected over the output capacitor is powered in this fashion.
[0009] To this basic SEFIC topology just described, a first embodiment of the present invention adds circuitry for over-voltage protection. Specifically, this embodiment uses over-voltage protection MOSFET to connect the input supply to the PWM control circuit and the node V w . The over-voltage protection MOSFET is driven by the output of a comparator. The comparator is connected to monitor the difference between a predetermined reference voltage V ref and the voltage of the input supply. If the voltage of the input supply exceeds the predetermined value V ref the comparator output causes the over-voltage protection MOSFET to disconnect the node V w and the PWM control circuit from the input supply. In this way, a SEPIC converter is provided that can survive input voltages that would otherwise damage the power MOSFET or PWM control circuit.
[0010] A second embodiment of the present invention provides a high-voltage SEPIC converter. For this embodiment (once again, based on the topology described above) a linear regulator (typically, an LDO) is used to supply current from the input supply to the PWM control circuit. In this way, the voltage applied to the PWM control circuit never exceeds the regulated output of the linear regulator and the SEPIC converter can survive input voltages that would otherwise damage the PWM control circuit.
[0011] A third embodiment of the present invention provides a high-voltage SEPIC with over-voltage protection. This embodiment includes all of the elements of the high-voltage SEPIC just described. To add over-voltage protection, an AND gate is added to drive the power MOSFET. The inputs to the AND gate are the output of the PWM control circuit and the output of a comparator. The comparator is connected to monitor the difference between a predetermined reference voltage V ref and the voltage of the input supply. If the voltage of the input supply exceeds the predetermined value V ref the comparator output causes the AND gate to disable the output of the PWM control circuit. In turn, this causes the power MOSFET to turn OFF.
[0012] By shutting down the power MOSFET under over-voltage conditions, the SEPIC converter ensures that the drain of the power MOSFET never exceeds the voltage of the input supply. In this way, the power MOSFET is protected in over-voltage conditions. At the same time, the PWM circuit is protected by the LDO as described for the previous embodiment.
[0013] A fourth embodiment of the present invention provides a high-voltage SEPIC with over-voltage protection and load disconnect. This embodiment includes all of the elements of the high-voltage SEPIC with over-voltage protection just described. To add load disconnect, current sensing and load disconnect circuitry is added to monitor the current flowing from the input supply to the high-side inductor. The current sensing and load disconnect circuitry includes a P-channel MOSFET connected between the input supply and the high-side inductor. During normal operation, this P-channel device is biased to allow current to pass to the high-side inductor.
[0014] The current through the P-channel MOSFET is monitored using a current mirroring technique. This produces an over-current signal that is connected as an input to the AND gate (in this implementation the AND gate has three inputs). If current flowing through the P-channel MOSFET exceeds a predetermined value, the over-current signal causes the AND gate to disable the output of the PWM control circuit. In turn, this causes the power MOSFET to turn OFF and protects the SEPIC converter from over-current damage. The use of a P-channel MOSFET to monitor the current to the high-side inductor also means that, by biasing that MOSFET to be OFF, the SEPIC converter may be disconnected from the input supply.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic of a conventional SEPIC converter (Prior Art).
[0016] FIG. 2 is a schematic of a SEPIC converter with series over-voltage protection as provided by an embodiment of the present invention.
[0017] FIG. 3 is a schematic of a high voltage SEPIC without over-voltage protection as provided by an embodiment of the present invention.
[0018] FIG. 4 is a schematic of a high voltage SEPIC with over-voltage protection as provided by an embodiment of the present invention.
[0019] FIG. 5 is a schematic of a high voltage SEPIC with over-voltage protection, current sensing, over-current protection and true load disconnect as provided by an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Over-Voltage-Protected SEPIC
[0021] One means to extend the voltage range of the SEPIC converter is to utilize an over-voltage protection, i.e. OVP, circuit that disconnects the converter from the input in the event the input voltage exceeds a pre-specified value. In converter 20 of FIG. 2 , SEPIC converter 21 is protected by P-channel MOSFET 31 controller by comparator 33 which compares the input voltage V IN to a reference voltage V ref . Reference voltage 34 may be implemented using a bandgap reference, Zener diode, a series of forward biased diodes or any other well known voltage reference technique, or a scaled multiple of said voltage. P-channel MOSFET 31 includes reverse-biased intrinsic P-N diode 32 with its anode tied to V IN and its cathode connected to the input to converter 21 .
[0022] SEPIC converter 21 comprises a PWM control circuit 22 , N-channel power MOSFET 23 with intrinsic drain-to-source diode 24 , high-side inductor 25 , capacitor 26 , low-side inductor 27 , rectifier diode 28 and output capacitor 29 powering load 30 . Operation comprises repeatedly magnetizing inductor 25 whenever MOSFET 23 is in its ON and conducting state and transferring energy to output capacitor 29 and load 30 in alternating phases.
[0023] Whenever V IN is below V ref the gate of P-channel 31 is pulled down by comparator 33 and P-channel 31 is turned on. The maximum gate to source voltage V GSP cannot exceed the maximum gate rating of the P-channel 31 , i.e. V GSP <|V IN −V GP |. Accordingly, the V cc input of SEPIC converter 21 is connected to V IN and the converter is operating. Whenever V IN is above V ref an over-voltage condition has occurred and the input V cc of SEPIC converter 21 is disconnected from V IN and allowed to float or alternatively is grounded. The V ref voltage determines the maximum value of V cc powering SEPIC converter 21 and PWM controller 22 . PWM controller must therefore utilize devices capable of operating at the maximum allowed V cc voltage, i.e. V ref . During operation, the node voltage V x peaks at a voltage (V IN +V OUT )<(V ref +V OUT ). The BV DSS breakdown of MOSFET 23 and diode 24 must exceed this peak voltage with some guardband.
[0024] As such OVP protection MOSFET 31 protects SEPIC converter 21 but must be rated for the maximum V IN input voltage. The devices used in PWM control circuit 22 must support the same voltage rating. An even higher voltage is imposed on node V x and across diode 24 of N-channel MOSFET 23 . Implementation 20 therefore requires two high voltage MOSFETs, N-channel 23 and P-channel 31 with respective on-resistances R DSN and R DSP , to implement an over-voltage protected SEPIC converter. The current capability of the converter is adversely affected by the higher on-resistance of such high voltage devices, i.e. R total =(R DSP +R DSN ). While the approach of circuit 20 may be used for any input voltage, practically these considerations limit the input voltage to the 12V to 18V range, especially in implementing PWM controller 22 .
[0025] Another benefit of OVP protected SEPIC converter 20 is its ability to implement the load-disconnect function, simply by turning OFF P-channel MOSFET 31 by biasing its gate to its source potential, i.e. where V GP =V IN .
[0026] High-Voltage SEPIC
[0027] Another method to extend the voltage range of the SEPIC converter is to utilize a high voltage low-drop-out linear regulator, or LDO, to protect the control circuitry from high voltages up to a pre-specified value. In SEPIC converter 50 of FIG. 3 linear regulator 60 limits the maximum voltage imposed on PWM controller 51 to some predefined maximum voltage V cc , typically 3V or 5V, so that the devices utilized within PWM circuit 51 may comprise only low-voltage devices.
[0028] SEPIC converter 50 includes a PWM control circuit 51 , N-channel power MOSFET 52 with intrinsic drain-to-source diode 53 , high-side inductor 54 , capacitor 55 , low-side inductor 56 , rectifier diode 57 and output capacitor 58 powering load 59 . Operation comprises repeatedly magnetizing inductor 54 whenever MOSFET 52 is in its ON and conducting state and transferring energy to output capacitor 58 and load 59 in alternating phases.
[0029] As illustrated linear regulator 60 is preferably a low-drop-out type, e.g. with a series voltage drop under 200 mV, to extend the operating voltage range of converter 50 to lower input voltage V IN . The design of low drop-out linear regulators is well known to one skilled in the art of power electronics. Input and output capacitors 61 and 62 acts as filter capacitors and prevent LDO 60 from oscillating. The benefit of the smaller sized devices is the silicon die area may be reduced compared to the area occupied by high voltage PWM circuit 22 of aforementioned SEPIC converter circuit 20 .
[0030] While LDO 60 protects PWM controller 51 from high input voltages it does not limit the voltage on the remainder of the converter circuit or on MOSFET 52 . Lacking any over-voltage protection circuitry and series disconnect switch, the N-channel MOSFET 52 and diode 53 must be rated to operate up to the maximum input voltage with adequate guard-banding to avoid accidental or momentary avalanche breakdown. During operation the peak V x voltage is typically (V IN +V OUT ).
[0031] Since only one high voltage MOSFET is present in converter 50 , the current capability of the converter is improved in comparison to converter 20 , where the total MOSFET resistance is only that of MOSFET 52 , i.e. where R total =(R DSN ). Without over-voltage protection however, the breakdown voltage of MOSFET 52 must be higher than (V IN +V OUT ). In this approach, the breakdown voltage guard-band of MOSFET 52 increases with increasing input voltage. While the approach of circuit 50 may be used for any input voltage, practically these considerations preferably limit the input voltage to the 18V to 30V range, beyond which the need for excessive voltage guard-banding makes MOSFET 52 unnecessarily large to compensate for its higher resistance.
[0032] Without OVP protection, one disadvantage of high-voltage SEPIC converter 50 is its inability to offer the load-disconnect function. As a result the circuit provides no means to disconnect load 59 from V IN .
[0033] High-Voltage SEPIC with Over-Voltage Protection
[0034] An improved SEPIC converter combines the over-voltage protection features of converter 20 with the high voltage capability of converter 50 . The resulting OVP protected high-voltage SEPIC converter is illustrated in circuit 69 of FIG. 4 . As such, an over-voltage protection circuit 83 in conjunction with a high voltage MOSFET 72 protects the power circuitry while a linear regulator protects the PWM control circuit 70 from high voltages. Unlike in converter 20 , OVP protection is achieved without inserting a second high voltage device in the high current path, but instead is achieved by changing the control of the high-voltage rated low-side N-channel MOSFET 70 .
[0035] Specifically, linear regulator 80 limits the maximum voltage imposed on PWM controller 70 to some predefined maximum voltage V cc , typically 3V or 5V, so that the devices utilized within PWM circuit 70 may comprise only low-voltage devices. Linear regulator 80 is preferably a low-drop-out type, e.g. with a series voltage drop under 200 mV, to extend the operating voltage range of converter 69 to lower input voltages V IN . The design of low drop-out linear regulators is well known to one skilled in the art of power electronics. Input and output capacitors 81 and 82 acts as filter capacitors and prevent LDO 80 from oscillating. The benefit of the smaller sized devices is the silicon die area may be reduced compared to the area occupied by high voltage PWM circuit 22 of aforementioned SEPIC converter circuit 20 .
[0036] For over-voltage protection SEPIC converter 69 achieves OVP capability by shutting OFF high-voltage MOSFET 72 whenever an over-voltage condition is detected. The maximum operating voltage of high voltage N-channel MOSFET 72 is set by OVP reference voltage 84 . Comparing the input voltage V IN to the reference voltage V ref , at the point of over-voltage shutdown when V IN >V ref , comparator 83 inhibits PWM control of MOSFET 72 with logic AND gate 71 . In such an event PWM controller 70 no longer determines the turn ON and OFF of MOSFET 71 . The maximum V x voltage at this moment is (V ref +V OUT ) plus some guard banding. Above this voltage, converter 69 no longer functions and the maximum voltage imposed on the drain of OFF state MOSFET 72 is simply V IN .
[0037] So in improved SEPIC converter 69 , the voltage capability of MOSFET 72 and diode 75 needed for operation is used to achieve the OVP function without adding extra series resistance to the high-current power path. Comparator 83 is used to monitor the input voltage V IN and compare it to an over-voltage reference set to a voltage V ref . Reference voltage 84 may be implemented using a bandgap reference, Zener diode, a series of forward biased diodes or any other well known voltage reference technique, or a scaled multiple of said voltage.
[0038] The remaining elements of SEPIC converter 69 comprises a PWM control circuit 70 , N-channel power MOSFET 72 with intrinsic drain-to-source diode 73 , high-side inductor 74 , capacitor 75 , low-side inductor 76 , rectifier diode 77 and output capacitor 78 powering load 79 . Normal operation comprises repeatedly magnetizing inductor 74 whenever MOSFET 72 is in its ON and conducting state and transferring energy to output capacitor 78 and load 79 in alternating phases.
[0039] Since only one high voltage MOSFET is present in converter 69 , the current capability of the converter is improved in comparison to converter 20 , where the total MOSFET resistance is only that of MOSFET 72 , i.e. where R total =(R DSN ). With over-voltage protection, the breakdown voltage of MOSFET 72 must be only slightly higher than (V ref +V OUT ) offering the need for less voltage guard banding and on-resistance penalty. Therefore, the approach of circuit 69 may be used for any input voltage with minimal impact on conversion efficiency.
[0040] Like converter 50 , without a series P-channel MOSFET, OVP protected high-voltage SEPIC converter 69 is unable to offer the load-disconnect function. As a result the circuit provides no means to disconnect load 79 from V IN .
[0041] High-Voltage SEPIC with Over-Voltage Protection and Load Disconnect
[0042] As another embodiment of this invention, improved SEPIC converter 80 combines the over-voltage protection features and load disconnect capability of converter 20 with the high voltage capability of converter 50 . The resulting OVP protected high-voltage SEPIC converter is illustrated in circuit 90 of FIG. 5 including current sensing and load disconnect circuitry 106 .
[0043] As such, an over-voltage protection comparator 104 in conjunction with a high voltage MOSFET 93 protects the power circuitry while a linear regulator 102 protects the PWM control circuit 91 from high voltages. Similar to converter 69 and unlike in converter 20 , OVP protection is achieved without inserting a second high voltage device in the high current path, but instead is achieved by changing the control of the high-voltage rated low-side N-channel MOSFET 93 .
[0044] To avoid the need for substantial high voltage circuitry, linear regulator 102 limits the maximum voltage imposed on PWM controller 91 to some predefined maximum voltage V cc , typically 3V or 5V, so that the devices utilized within PWM circuit 91 may comprise only low-voltage devices. Linear regulator 80 is preferably a low-drop-out type, e.g. with a series voltage drop under 200 mV, to extend the operating voltage range of converter 90 to lower input voltages V IN . The design of low drop-out linear regulators is well known to one skilled in the art of power electronics. Input and output capacitors 101 and 103 acts as filter capacitors and prevent LDO 102 from oscillating. The benefit of the smaller sized devices is the silicon die area may be reduced compared to the area occupied by high voltage PWM circuit 22 of aforementioned SEPIC converter circuit 20 .
[0045] For over-voltage protection SEPIC converter 90 achieves OVP capability by shutting OFF high-voltage MOSFET 93 whenever an over-voltage condition is detected. The maximum operating voltage of high voltage N-channel MOSFET 93 is set by OVP reference voltage 105 . Comparing the input voltage V IN to the reference voltage V ref , at the point of over-voltage shutdown when V IN >V ref , comparator 104 inhibits PWM control of MOSFET 93 with triple-input logic AND gate 92 . In such an event PWM controller 91 no longer determines the turn ON and OFF of MOSFET 93 . The maximum V x voltage at this moment is (V ref +V OUT ) plus some guard banding. Above this voltage, converter 90 no longer functions and the maximum voltage imposed on the drain of OFF state MOSFET 93 is simply V IN .
[0046] In improved SEPIC converter 90 the voltage capability of MOSFET 93 and diode 94 needed for operation is used to achieve the OVP function without adding extra series resistance to the high-current power path. Comparator 104 is used to monitor the input voltage V IN and compare it to an over-voltage reference set to a voltage V ref . Reference voltage 105 may be implemented using a bandgap reference, Zener diode, a series of forward biased diodes or any other well known voltage reference technique, or a scaled multiple of said voltage.
[0047] Current sensing is achieved in improved SEPIC converter 90 using current sensing and load disconnect circuitry 106 , utilizing a low-loss current sensing technique described in a pending U.S. patent application entitled “Cascode Current Sensor for Discrete Power Semiconductor Devices” by R. K. Williams. That disclosure is incorporated in this document by reference. Rather than using a resistor as a current sense element, low-voltage low-resistance P-channel MOSFET 107 with intrinsic reverse biased P-N diode 108 is inserted in the path of the input current flowing in inductor 95 . Under normal operation the gate voltage V GP of P-channel 107 is pulled down by gate buffer 109 to fully enhance the MOSFET into a low-resistance state with a resistance R DSP for a given area substantially lower than that of high-voltage P-channel 31 described previously in FIG. 20 .
[0048] The maximum gate to source voltage V GSP of P-channel 108 in its ON condition cannot exceed the maximum gate rating of the P-channel 107 , i.e. V GSP <|V IN −V GP | as determined by the output of gate buffer 109 . When MOSFET 107 is ON and conducting, amplifier or comparator 110 is used to determine the input current flowing into inductor 95 . By using a mirror technique the current in MOSFET 107 can be accurately determined.
[0049] During normal operation, the gate buffer 109 biases MOSFET 107 into a low-resistance conducting state. Amplifier or comparator 110 accurately detects the current flowing in conducting MOSFET 107 and outputs a signal. If this signal is analog, representing a measurement of inductor 95 current, the information may be used to implement current mode control of PWM block 91 .
[0050] In another implementation shown in FIG. 5 , comparator 110 has a digital output representing over-current protecting shutdown or OCS, and used as one input to triple NAND gate 110 . Only when converter 90 has an input voltage V IN below a specified preset level and the measured current in MOSFET 107 does not cause comparator 110 to flip states as an over-current condition, then the output of PWM controller 91 controls the turning ON and OFF of N-channel MOSFET 93 . Accordingly, the V w input of SEPIC converter 90 is connected to V IN and the converter is operating.
[0051] The remaining elements of SEPIC converter 90 comprises a PWM control circuit 91 , N-channel power MOSFET 93 with intrinsic drain-to-source diode 94 , high-side inductor 95 , capacitor 96 , low-side inductor 97 , rectifier diode 98 and output capacitor 99 powering load 100 . Normal operation comprises repeatedly magnetizing inductor 95 whenever MOSFET 93 is in its ON and conducting state and transferring energy to output capacitor 99 and load 100 in alternating phases.
[0052] Since only one high voltage MOSFET 93 plus one low-voltage MOSFET 107 is present in converter 90 , the current capability of the converter is improved in comparison to converter 20 , where the total MOSFET resistance is that of high-voltage MOSFET 93 plus the resistance of low-voltage MOSFET 107 , i.e. where R total =(R DSP +R DSN ). With over-voltage protection, the breakdown voltage of MOSFET 93 must be only slightly higher than (V ref +V OUT ) offering the need for less voltage guard banding and on-resistance penalty. Therefore, the approach of circuit 90 may be used for any input voltage with minimal impact on conversion efficiency.
[0053] By including series low voltage P-channel MOSFET 107 , the disclosed OVP protected high-voltage SEPIC converter 90 is able to offer the load-disconnect function whereby the circuit provides a means to disconnect load 100 from V IN . Load disconnect is controlled by P-type current sense PCS signal, the input to gate buffer 109 .
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A SEPIC converter with over-voltage protection includes a high-side inductor that connects a node V w to a node V x . The node V x is connected, in turn to ground by a power MOSFET. The node V x is also connected to a node V y by a first capacitor. The node V y is connected to ground by a low-side inductor. A rectifier diode further connects the node V y and a node V out and an output capacitor is connected between the node V out and ground. A PWM control circuit is connected to drive the power MOSFET. An over-voltage protection MOSFET connects an input supply to the PWM control circuit and the node V w . A comparator monitors the voltage of the input supply. If that voltage exceeds a predetermined value V ref the comparator output causes the over-voltage protection MOSFET to disconnect the node V w and the PWM control circuit from the input supply.
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BACKGROUND
1. Technical Field
The present invention concerns a felting device for felting fiber materials and methods of felting and an article produced by felting.
2. Description of the Related Art
Felting of fiber materials, in particular wool materials, has long been known and a distinction is basically drawn between two felting technologies, dry felting and wet felting. In both technologies, basically the raw wool sheared from the sheep, washed, dried and combed is processed in such a way that the result produced is in particular a closed, fixedly joined felt layer or felt form.
The term fiber materials is basically used hereinafter to denote all materials consisting of fibers, in particular this includes both raw material and also processed material. In the case of processed material this can basically be of any form. Fiber materials in the present case include in particular wool such as sheep's wool, yak wool, alpaca wool and also angora to give just some examples. In addition fiber materials also include vegetable materials such as cotton or hemp fibers. Fiber materials can also involve artificial, industrially manufactured materials.
The present invention concerns dry felting. In dry felting for example a felting needle which is about 8 cm in length and which is ground into a triangular configuration and which has barbs at the tip is repeatedly pushed into the raw wool. Barbs at the tip of the needle cause the individual fibers of the raw wool to be hooked together in each movement. That procedure has to be repeated until a firm closed layer has been formed at least in the desired region and the fibers are felted together. In that way for example it is also possible for two felt layers to be joined together, more specifically felted together, if the felting needle is repeatedly pushed through both layers which bear against each other and the fibers of the two layers hook into each other so that the layers are joined together.
Thus basically so much wool in a plurality of layers can be applied to each other or to an existing article and processed until the result is a desired form. In that way for example a ball, a felt animal, a hat or a slipper can be produced or improved. Basically it is possible in that way to produce virtually any desired form.
A disadvantage in that respect is that this kind of manual felting in the long term is very strenuous and tiring. To accordingly achieve an improvement, felting by means of a machine has already been proposed. Such a machine is essentially similar to a sewing machine, without a bobbin thread. Basically, instead of a sewing needle, a felting needle is moved with an oscillating motion and for the felting operation the corresponding layers to be felted are moved along between the oscillating felting needle and a backing plate. Felting with such a machine is much faster in contrast to manual felting.
Such felting machines include a needle region for movement of the needle, a backing plate or plate and a side arm connecting the two and are thus of considerable size and weight and are correspondingly difficult to move and are therefore arranged stationarily in use. A further disadvantage is that only objects up to a certain size can be processed with such machines as the objects have to be passed through in the limited space between the needle, the plate and the side arm.
Another disadvantage with such machines is that it is practically not possible to felt hollow objects in which for example something is to be applied by felting to an outer layer or wall of the hollow object. In the case of a slipper for example there is the risk that, when attempting to felt something on to its top side, it could be felted to the lower side, which is not wanted.
BRIEF SUMMARY
Therefore one object of the present invention is to reduce one of the above-described problems. Another embodiment provides a solution for facilitating manual felting that avoids the disadvantages of previously known felting devices. The invention seeks to propose an alternative.
According to the invention therefore there is proposed a felting device for felting fiber materials as set forth in claim 1 .
Such a felting device thus includes a needle receiving means for receiving and holding a felting needle for performing the felting operation. Thus for example a known felting needle can be received and held fast with its rear side in the needle receiving means. Preferably such felting needles are interchangeable. It is however also conceivable that a felting needle is fixedly connected to the needle receiving means of the felting device without provision for exchanging an individual felting needle.
The felting device further includes a drive motor for moving the needle receiving means in order thereby ultimately to move the inserted felting needle. In particular the arrangement involves an oscillating movement of the needle receiving means with inserted felting needle in the longitudinal direction of the felting needle. The drive motor is preferably in the form of an electric motor. Basically however other motors can be considered, such as for example a drive by a spring storage means with a spring which can be tightened up, such as for example a spiral spring which can be wound up similarly to a mechanical clock.
Finally there is proposed a housing for movably holding and guiding the felting device with a hand. In that way it is possible for the felting device to be guided with a hand along the object to be felted at the desired location or the desired region and for the felting operation to be performed by the oscillating felting needle. Basically the size and shape of the object to be felted are not important. The felting device according to the invention can also be referred to as a hand felting device or portable hand felting device. It is preferably twice as fast as a commercially available felting device as described hereinbefore. In comparison therewith the hand felting device according to the invention is particularly small, manageable, light and mobile. Its manageable light construction also makes it possible to achieve an energy-saving structure.
With the felting device according to the invention it should now be possible basically to felt any large, small, three-dimensional and hollow objects. The structure involved makes it possible for a large radius of action to exist at all sides as the hand felting device is appropriately held with its housing in a hand and the operator can thus felt around the object in question. The object to be felted does not now have to be moved as in the case of the above-described machines. Particularly in the case of very large, heavy, unmanageable and also in the case of very small objects, that can be a very major advantage. Because of the size and the low weight of the hand felting device which is to be guided by hand, it can basically be used everywhere. If the hand felting device itself does not have an energy storage means for operating the drive motor the need for an electric connection still at most limits the range of use. When employing an electric motor with accumulator or battery in the hand felting device even that limitation disappears and the hand felting device according to the invention can also be readily used for example in the open air. Finally felting of hollow articles can be made easier because the user, with the felting device in the hand, can more accurately determine and control the depth of penetration of the needle. The risk of the needle penetrating through a hollow space into an opposite side and thus causing felting through the hollow space which is undesirable, can thus be eliminated or at least however reduced.
The housing can preferably accommodate all components of the felting device so that essentially there is only still the felting needle that partially projects out of the housing. Completely accommodating the components of the felting device however is not a necessary prerequisite for the housing. Rather the felting device is to be guided with a hand by means of the housing and in that respect, instead of the housing or in addition thereto, there can be provided a holding means for movably holding and guiding the felting device with a hand.
In an embodiment the felting device is characterized by a guide means for axially guiding the felting needle and/or the needle receiving means. That can provide for axial movement of the felting needle and thus accurate felting. The guide means can be for example a guide shank, in particular a cylindrical guide shank, in which the felting needles and/or the needle receiving means slides in the axial direction. Preferably the needle receiving means is guided so that the guide means can be substantially independent of the size and configuration of the felting needle and also no problems of slidingly guiding the barbs of a felting needle arise. In such a case the felting needle can be simply replaced by a new one and/or by another one as required without this having to have an influence on guidance.
A further embodiment proposes a felting device characterized in that there is provided a joint connection, in particular a cardan joint, for coupling the needle receiving means to the drive motor, in order to convert a non-axial movement, caused by a rotary movement of the drive motor, into an axial oscillating movement of the felting needle. A rotary movement of the drive motor can basically be converted similarly to a crankshaft and connecting rod into a substantially translatory, that is to say axial, movement. By virtue of a further connection by way of a cardan joint in relation to the needle receiving means, it is possible for the needle receiving means or the felting needle to provide a basically completely axial movement, the rectilinearity of which ultimately depends on the guide means. Such conversion can easily be achieved by the cardan shaft. In principle a joint connection with a simple joint can be sufficient. The use of a cardan joint provides greater tolerance in relation to lack of synchronicity and uniformity of motion in the upstream-connected drive train and can compensate for tolerances. In addition it is possible to provide a simple and compact structure whereby guiding the felting device with a hand in accordance with the invention is facilitated.
In that way it is possible to produce an axial or linear movement by means of a commercially usual rotating motor, in particular an electric motor. In another embodiment it is also possible to provide a linear motor which directly produces the desired linear oscillating motion. That can be achieved for example by means of two electric coils which produce the oscillating movement by alternate current feed thereto.
As a further embodiment there is proposed a pushbutton switch for switching the drive motor on and off and/or starting and stopping a needle movement of the felting needle. Thus the felting needle is moved when the pushbutton switch is pressed and stops moving as soon as the pushbutton switch is no longer pressed. The pushbutton switch thus permits easy handling and is preferably so arranged that it can be actuated at the same time with the same hand as that with which the felting device is also held and moved. Preferably the pushbutton switch is arranged directly on the housing. In that way the felting device can be easily operated with one hand and can be switched on and off almost as desired. In particular frequently stopping the device in one region and starting it up again in another region is simplified.
Thus the movement of the felting needle is to be controlled by the pushbutton switch. That can be effected by starting or stopping the motor or also by an intervention at another location, such as for example by interrupting the drive train between the motor and the felting needle.
In a further preferred embodiment there is proposed a felting device which is characterized in that the drive motor is in the form of an electric motor, in particular a dc motor, and/or is supplied with electric current by way of an energy storage means accommodated in the housing, in particular a battery or accumulator.
The use of an electric motor affords a simple possible form of implementation of a hand felting device. The power supply to the electric motor can be connected or interrupted by a switch such as a button switch in order thereby to start or stop the motor and thus the movement of the felting needle. The use of an energy storage means such as a battery or accumulator means that the felting device is independent of an external power supply and troublesome cables can be eliminated. A dc motor can be simply coupled to a battery or accumulator as they also supply a dc voltage or a direct current.
Preferably the guide means for axially guiding the felting needle or the needle receiving means opens with a front end into a housing opening or such an end forms a housing opening. In that respect, in that case the structure should be such that the felting needle when used as intended for the felting operation is pushed out of that opening and pulled into it again in an oscillating motion. In that respect the felting needle can be pulled in each case so completely into the opening that in the pulled-in condition it no longer projects from the opening. In that case the felting device can be guided with that housing opening along the region to be felted of the object to be felted. In particular that easily permits uniform felting.
It is desirable if the felting device is characterized in that the length by which the felting needle projects at a maximum out of the or a housing opening during a movement for the felting operation is adjustable. That makes it possible to adjust the depth of penetration of the felting needle into the object to be felted. That depth of penetration corresponds to the length by which the felting needle projects at a maximum out of the housing opening when the housing opening is guided directly along the surface of the object to be felted. Depending on the respectively required depth of penetration the projection length can then be adjusted. For example, when felting two felt layers which are placed one upon the other, the overall thickness thereof can be adjusted as the length by which the felting needle projects at a maximum out of the housing opening. In addition such adjustability also makes it possible to adapt the felting device to felting needles of differing lengths.
Adjustability can be achieved for example by a telescopic opening or also by a change in the position of the needle receiving means within the felting device, by for example the spacing between the needle receiving means and the connection to the motor being shortened or lengthened. The spacing between the or a joint connection like a cardan joint to the needle receiving means can also be adapted to be adjustable for that purpose.
The depth of penetration can also be influenced by a change in a stroke travel of the needle receiving means and therewith the felting needle. The stroke length which can also be described as the oscillation amplitude can also influence the length of movement within the material to be felted.
Preferably the or a guide means for axially guiding the felting needle or the needle receiving means is in the form of a sleeve. The felting needle and/or needle receiving means can thus be guided in the axial direction in the sleeve. Adjustability of the length by which the felting needle projects at a maximum out of a housing opening can also be achieved by pulling the sleeve out or pushing it in, if an end of the sleeve terminates with the housing opening.
A felted article which was produced by means of a felting device according to the invention can be recognized—depending on the respective embodiment of the felting device—by the uniformity of felted regions, in particular a uniform depth of penetration of a felting needle and the resulting felting depth.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The invention is described by way of example hereinafter by means of an embodiment with reference to the accompanying Figures in which:
FIG. 1 shows a perspective view of a felting device according to the invention with an opened housing cover,
FIG. 2 shows an exploded perspective view of the felting device according to the invention as shown in FIG. 1 ,
FIG. 3 shows a side view of a pushbutton switch,
FIG. 4 shows a perspective view of a needle receiving means,
FIG. 5 shows a sectional side view of the needle receiving means 20 in FIG. 4 , and
FIG. 6 shows a sectional side view of a guide sleeve.
DETAILED DESCRIPTION
The felting device 1 in FIG. 1 has a housing 2 with opened housing cover 4 . The housing 2 has a motor portion 6 for accommodating a motor and a guide portion 8 having a housing tip 10 and a housing opening 12 .
Accommodated in the motor portion 6 is a motor which drives a rotary disk or a disk 14 which transmits a rotary movement to a connecting rod 16 which in turn transmits the movement by way of a cardan joint 18 to a needle receiving means 20 . The needle receiving means 20 is guided together with an inserted felting needle in a guide cone 22 . For that purpose the guide cone 22 has an internal bore in the axial direction of the needle receiving means and thus in the axial direction of an inserted felting needle, in which the needle receiving means 20 is guided slidingly in the axial direction. The guide cone thus operates as a guide means.
FIG. 1 shows the felting device 1 in a condition in which the needle receiving means 20 and thus a felting needle is in a maximum retracted position. Therefore in the view in FIG. 1 a felting needle does not project out of the housing 2 and in particular not out of the housing tip 10 .
By initiating a rotary movement of the rotary disk 14 however the connecting rod 16 , the cardan joint 18 and the needle receiving means 20 are moved together with an inserted felting needle in a direction towards the housing opening 12 whereby the felting needle is pushed out of the housing opening 12 —thus towards the right in FIG. 1 .
FIG. 2 is an exploded view showing further details of the felting device. Accordingly there is provided an electric motor 24 accommodated in the motor portion 6 of the housing 2 . The electric motor 24 has a motor shaft 26 which is torsionally rigidly connected to the rotary disk 14 . The rotary disk 14 has an eccentric opening 28 to which the connecting rod 16 is rotationally fixed by means of a screw 30 and a nut 32 .
The connecting rod 16 is connected to the needle receiving means 20 by means of a cardan joint 18 . The needle receiving means 20 has a receiving opening 34 into which a felting needle can be inserted and connected to the needle receiving means 20 .
To insert or exchange a felting needle the housing cover 4 can be opened and, after release of the nut 32 , the needle receiving means 20 together with the cardan joint 18 and the connecting rod 16 can be removed from the housing 2 to insert a felting needle. In other embodiments the felting needle can be inserted directly through the housing opening 12 into the needle receiving means 20 and fixed for example by means of a bayonet connection, possibly the tip 10 would have to be removed for that purpose.
In the illustrated embodiment the electric motor 24 is arranged substantially with its longitudinal axis in transverse relationship to the longitudinal axis of the needle receiving means 20 . That is a particularly efficient structure which in addition makes it possible to implement a housing 2 which as illustrated is of an approximately angular configuration. Such a housing and therewith the felting device overall can be well managed with a hand and this also makes it possible for the housing to be held in different ways.
The felting device shown by way of example is substantially of a length of 16.3 cm, a width of 11 cm, which substantially corresponds to the length of the motor portion 16 , and a depth of 4.3 cm. In this case the entire felting device weighs only about 250 g. The drive used is a 12 V motor which is powered by way of a power pack which is not subject-matter of this embodiment and is also not shown in the Figures. The power consumption of the drive is at a maximum loading 7 W at 0.7 A. The motor has a nominal rotary speed of 2500 rpm.
The housing comprises glass fiber-reinforced plastic impregnated with epoxy resin.
The handle of the housing is of a cylindrical shape and ends in a hemisphere and accommodates the motor. The hemisphere identified by reference 36 has an opening with a bush outwardly for the power connection for powering the motor. That power connection bush, not shown in the Figure, is connected in the interior of the housing by way of a power cable both to the motor and also to an on/off switch. The on/off switch which is in the form of a pushbutton switch is mounted externally on the housing. Such a pushbutton switch is shown in a side view in FIG. 3 . The motor can be started and stopped by that switch.
The screw 30 on the rotary disk 14 serves at the same time as a pin to which the connecting rod 16 is connected. In this interaction the needle receiving means 20 serves at the same time as a pushrod and thus the rotary movement of the motor is converted into a linear stroke movement. The stroke travel or an oscillation amplitude can be varied by a variation in the radius of the rotary disk 14 or by a variation in the spacing of the screw 30 relative to the center point of the rotary disk 14 —the effective radius of the rotary disk.
To accommodate a commercially usual felting needle the needle receiving means 20 has a groove which is milled in centrally in respect of length, as will be described hereinafter. The guide portion 8 of the housing 2 is of a configuration that converges conically towards the opening 12 and in its interior directly in front of the opening 12 has a guide casing which is bonded in position there and in which the pushrod or the needle receiving means 20 together with the felting needle moves to and fro.
A switch 38 shown in FIG. 3 is in the form of a pushbutton switch. The switch 38 has a switching knob 40 which closes a circuit by being pushed into the switch and which opens it again when it is released. To simplify pressing and releasing the switching mechanism there is provided a switching lever 42 which is fixed to the switch 38 and by way of which the switching knob 40 is pressed. The switch 38 is so arranged on the housing 2 of the felting device that the switching lever 42 is arranged substantially flat in relation to the housing 2 and can thus be easily actuated by the operator. Namely, the lever 42 can form one wall of the housing 2 , so that pressing on a selected location of the housing, the switch 40 is pressed to turn the motor either on or off, as a toggle switch. Alternatively, the lever 42 can be adjacent to the housing 2 .
The needle receiving means 20 is shown as an individual element in FIG. 4 and is shown on an enlarged scale as a perspective view. It has a connecting portion 44 for connection to the cardan joint 18 . A groove 46 is milled centrally in the needle receiving means 20 in opposite relationship to the cardan joint 18 to hold a felting needle therein.
In addition there is also a longitudinally axial bore (not shown in the Figure) which is concentric relative to the needle receiving means, for holding the felting needle. That longitudinal bore is of a diameter slightly larger than the thickness of the groove 46 . That affords a kind of channel at each side of the groove 46 , as can be seen from the sectional side view in FIG. 5 . The axial bore is denoted there by reference 48 .
Finally the needle receiving means 20 also has a transverse bore 50 . That can be used for fixing a felting needle, in particular a commercially usual felting needle, which at its rear end has an angled portion which in use as intended is accommodated in the transverse bore 50 .
FIG. 6 shows a sectional side view illustrating a guide sleeve 52 arranged in the guide cone 22 for guiding the needle receiving means 20 . The guide sleeve is concentric relative to a center line 53 and has a cylindrical guide portion 54 , a central portion 56 and a tip portion 58 . Provided in the cylindrical guide portion 54 is a longitudinally axial bore which is of an inside diameter adapted to the outside diameter of the needle receiving means 20 to be guided. By way of example the outside diameter of the needle receiving means 20 in the relevant region is 6 mm and the inside diameter of the guide portion 54 is 6.5 mm. The needle receiving means 20 can thus be guided slidingly in the axial direction in the bore 60 .
The central portion 56 and the tip portion 58 are arranged together in a conical tip region and also each have a concentric bore which is at least slightly larger in diameter than a felting needle to be accommodated. In this case the end portion 58 has a support bore 62 which is of an only slightly larger inside diameter than the diameter of a felting needle to be used. It is possible in that way for the felting needle to be supported in the support bore 62 in the case of any transverse forces which occur.
The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent application, foreign patents, foreign patent application and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, application and publications to provide yet further embodiments.
These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
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The present invention concerns a felting device for felting fiber materials including a needle receiving means for receiving and holding a felting needle for performing the felting operation, a drive motor for moving the needle receiving means for moving the inserted felting needle and a housing for movably holding and guiding the felting device with a hand.
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[0001] The present invention relates to a protective covering for a structure, and more particularly, a protective covering for a structure that can be easily installed from the inside or the outside of the structure to which it is attached and which may also be adjustable.
[0002] There are several prior art protective coverings or hurricane shutters, however, the majority of those protective coverings have many panels that need to be individually installed and secured or require more than one person to install. These coverings take a long time and require a lot of effort to mount on the structures. Therefore, once these are installed, they are usually left mounted for extended periods of time, making the structure extremely dark and uninviting. There are other protective coverings that require reinforcement members or complicated elements or brackets to attach the shutters or protective device to the structures. Again, these take a long time to install and are usually left in place once installed.
[0003] Accordingly, the present invention is directed to a protective covering and method for installing a protective covering on a structure that substantially obviates one or more of the problems and disadvantages in the prior art. Additional features and advantages of the invention will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the apparatus and process particularly pointed out in the written description and claims, as well as the appended drawings.
SUMMARY OF THE INVENTION
[0004] To achieve these and other advantages and in accordance with the purpose of the invention as embodied and broadly described herein, the invention is directed to removable, adjustable protective covering for protecting an opening in a structure that includes a first panel, the first panel having an upper edge configured to be attached to a portion of the structure adjacent one side of the opening, and a second panel, the second panel configured to be secured to the first panel and having a lower edge configured to be attached to a portion of the structure adjacent an opposite side of the opening.
[0005] In yet another aspect, the invention is directed to an adjustable protective covering for protecting an opening in a structure that includes a first panel for covering at least a portion of the opening in the structure and a second panel for covering at least a portion of the opening and configured to be adjustably secured to the first panel, wherein the first and second panels secured to one another having a size that covers at least a portion of the opening in the structure.
[0006] In another aspect, the invention is directed to a removable, adjustable protective covering assembly for protecting an opening in a structure that includes a first panel, the first panel having an upper edge configured to be attached to a portion of the structure adjacent one side of the opening, a plurality of central panels, each of the central panels having a top edge configured to engage a previous panel and a bottom edge configured to engage a next panel, and a final panel, the final panel configured to be secured to one of the plurality of central panels and having a lower edge configured to be attached to a portion of the structure adjacent an opposite side of the opening; wherein the securing of the final panel to the structure locks the panels to protect the opening in the structure.
[0007] In another aspect, the invention provides a removable protective covering for protecting an opening in a structure that includes a protective panel sized to cover at least a portion of the opening, the protective panel having an edge configured to be attached to a portion of the structure adjacent a first side of the opening, and a securing means mounted to at least a second side of the opening to secure the protective panel over the at least a portion of the opening.
[0008] In yet another aspect, the invention provides for a method of installing a protective covering for protecting an opening in a structure that includes providing a first panel for covering at least a portion of an opening in the structure and a second panel for covering at least a portion of the opening and configured to be adjustably secured to the first panel, the first and second portions covering a majority of the opening, attaching the first panel to a first side of the opening from inside the structure, attaching the second panel to a second side of the opening from inside the structure, and securing the first panel to the second panel from inside the structure with mechanical fasteners such that the fasteners are not easily removable from outside the structure.
[0009] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
[0010] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification. The drawings illustrate several embodiments of the invention and together with the description serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a front view of one embodiment of a protective covering mounted on a structure according to the present invention;
[0012] FIG. 2 is a side view of the protective covering in FIG. 1 prior to being attached to the structure;
[0013] FIG. 3 is a side view of the protective covering in FIG. 1 attached to the structure over an opening;
[0014] FIG. 4 is an attachment member used in conjunction with the protective covering of FIG. 1 and mounted to the structure;
[0015] FIG. 5 is a side view of another embodiment of a protective covering according to the present invention;
[0016] FIG. 6 is a front view of another embodiment of a protective covering according to the present invention;
[0017] FIG. 7 is a side view of the protective covering of FIG. 6 ;
[0018] FIG. 8 is a partial view of another embodiment of a protective covering according to the present invention;
[0019] FIG. 9 is a partial view of the protective covering of FIG. 8 with the securing hardware reversed for interior mounting;
[0020] FIG. 10 is a side view of another embodiment of a protective covering according to the present invention;
[0021] FIG. 11 is a front view of another embodiment of a protective covering according to the present invention;
[0022] FIG. 12 is a cross sectional view of the protective covering of FIG. 11 along the line 12 - 12 ; and
[0023] FIG. 13 is a side view of another embodiment of a protective covering according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] A protective covering 20 according to one embodiment of the present invention is illustrated in FIG. 1 . The protective covering 20 has preferably two panels an first panel 22 and a second panel 24 . The first and second panels 22 , 24 are secured to one another by mechanical fasteners 26 . The mechanical fasteners 26 are preferably a bolt or machine screw 28 and a wing nut 30 . The mechanical fasteners 26 may also be other mechanical fasteners such as a rod with a head and shaft where the shaft has a groove to allow a snap lock ring or other types of securing fasteners. The bolt or screw 28 may be of any type, size, or configuration that is appropriate to secure the panels 22 , 24 together. The wing nut 30 may also be any other type of nut or engagement member as long as it holds the two panels together with the bolt or screw 28 . The second panel 24 , which is illustrated as being the lower panel in the figures, has an opening 32 through which the bolt or machine screw 28 passes. The openings 32 may be small enough to engage a shank on the bolt or machine screw 28 to prevent rotation of the bolt or machine screw 28 when the wing nut 30 is secured. If a shank is provided, then bolt or machine screw 28 need not have a slotted head, but could be smooth. Similarly, the first panel 22 preferably has slots 34 for each of the mechanical fasteners to protrude through and engage the wing nut 30 or any other type of nut. This feature of non-rotation of the bolt or machine screw may also be provided by the shape of the shank or a part of the shank that is not round, such as square, and this shape is matched by the shape of the corresponding opening in the panel.
[0025] The panels 22 , 24 are preferably attached to the structure 36 over an opening 38 with an attachment members 40 that are previously secured to the structure 36 . The attachment members 40 are best seen in FIG. 4 . The attachment members 40 are preferably made from steel or other metal to provide the most security and safety. The attachment members 40 preferably have a flat back portion 42 and a curved portion 44 , approximately forming a J-shape. See FIG. 2 . The attachment members 40 are secured to the structure 36 with screws or bolts 46 in opposite directions. As can best be seen in FIG. 2 , the top attachment member 40 is attached with the curved portion 44 opening in an upward direction (away from the opening in the structure), while the bottom attachment member 40 is attached with the curved portion 44 opening in a downward direction (away from the opening in the structure). The panels 22 , 24 also have a curved portion 48 along one edge to engage the attachment members 40 as illustrated in FIG. 3 . While the panels 22 , 24 and the attachment members 40 have curved portions to engage one another, the portions may be more square or even in a sharper curved shape, approaching more of a V-shape rather than a J-shape.
[0026] The attachment members 40 are preferably mounted well in advance of the need to use the protective covering 20 . The attachment members 40 may be painted or otherwise treated to make them appear to be a part of the structure 36 .
[0027] The panels 22 , 24 are preferably made of sheet metal that is approximately 1.5 to 2.0 mm thick. The panels 22 , 24 may also be made of a clear plastic material (i.e., acrylic, polycarbonate) that is thick enough (about 3.0 to 6.5 mm) to comply with the hurricane standards along the coasts, but also allows light to enter the structure. However, thicker or thinner panels may be used.
[0028] To mount the panels to the attachment members 40 , preferably the first panel 22 is loosely attached to the second panel 24 , and the curved portion 48 of first panel 22 is placed into the curved portion 44 of the attachment member 40 attached to the structure 36 adjacent the opening 38 . The panels 22 , 24 are then pushed against the structure 36 and the second panel 24 is pushed upward such that the curved portion 48 engages the curved portion 44 of the attachment member 40 . Once the lower panel 24 engages the attachment member 40 , the mechanical fasteners 26 is tightened, securing the protective covering 20 to the structure 36 .
[0029] Alternatively, the first panel 22 could be mounted on (hung on) the attachment member 40 and then the second panel 24 could be loosely attached to the first panel 22 , before being pushed up to engage the lower attachment member 40 and secured with the mechanical fasteners.
[0030] An alternative way of mounting the protective covering 20 is illustrated in FIG. 5 . The protective covering 20 is the same as that illustrated in FIGS. 1-4 , but the attachment members 40 are not needed in this embodiment. In this embodiment, the structure has an opening 50 (and a window in this particular illustration) that has a lip 52 to which the curved portions 48 of panels 22 , 24 are attached. The protective covering is mounted in the same way as described above, with the lip 52 functioning as the attachments members.
[0031] Another alternative embodiment of the protective covering according to the present invention is illustrated in FIGS. 6 & 7 . The protective covering 60 is similar to protective covering 20 but has a flange 62 on each side that provides strength and stability to first panel 64 . While second panel 66 does not have the flanges 62 , the flanges could be added to the second panel 66 as well. The first panel 64 and the second panel 66 are the same as those discussed above, including having mechanical fasteners 68 that pass through holes 70 in the second panel 66 and slots 72 in the first panel to secure them to one another. The first and second panels also have curved portions 74 , that are used to attach the panels 64 , 66 to the structure as in the prior embodiments.
[0032] An alternative arrangement for securing the panels of the protective covering is illustrated in FIG. 8 . In this embodiment, only a portion of which is shown, the first panel 22 ′ and second panel 24 ′ have an energy absorber 80 inserted where the two panels 22 ′, 24 ′ overlap and are secured to one another by mechanical fastener 82 . The energy absorber 80 may any material that reduces noise and shock when the panels 22 ′, 24 ′ are impacted by flying objects or even the wind. Such materials may include rubber elastomers, foam, cork, and synthetic polymeric materials.
[0033] The embodiment illustrated in FIG. 9 is similar to that in FIG. 8 , except that the mechanical fastener 82 is turned round, with the wing nut 84 facing the inside of the structure. In this configuration, the protective covering may be installed from the inside of the structure. The panels are carried to the opening and installed as noted above. The final tightening of the mechanical fastener 82 is then done from the inside, preventing someone from the outside from unfastening the fastener 82 . Preferably, the screw or bolt 86 has no slots or other configurations to allow a person to gain access. The screw or bolt 86 may also be secured to one of the panels (by welding or any other appropriate manner) to prevent the removal of the bolt or screw. Additionally, while the second panel 88 is illustrated to be on the inside of the first panel 90 , it may also be on the outside of the first panel 90 .
[0034] Another embodiment of a protective covering is illustrated in FIG. 10 . In this embodiment, protective covering 100 is a single panel 102 that has a curved portion 104 at the top to cooperate with an attachment member 106 , that is similar to the attachment members discussed above. The panel 102 attaches to a screw or bolt 108 attached to the structure 110 with a wing nut 112 or any other appropriate fastener, as discussed above. The protective covering 100 is preferably for smaller openings 114 , so that the panel 102 is not too heavy for the owner to lift and put in place.
[0035] Another embodiment of a protective covering 120 is illustrated in FIGS. 11 and 12 . The protective covering 120 has multiple horizontal covering part of an opening in a structure and multiple vertical panels that are linked to those horizontal panels. Protective covering 120 is similar to the other protective coverings in FIGS. 1 and 6 in that they have two panels, a first panel 122 and a second panel 124 , that cooperate to cover the opening from the top to the bottom of the structure. However, the protective covering 120 also has panels ( 122 ′, 122 ″, 124 ′, 124 ″) that extend across the opening, especially when the opening is relatively large, such as a sliding glass door or a large picture window. Otherwise, each of the panels 122 , 124 may be too large to handle. As can best be seen in FIG. 12 , each of the panels has a portion 126 that is off set to and receives the neighboring panel, for example panel 122 receives panel 122 ′. Each of the panels has additional holes and slots to allow a fastener 128 to secure the overlapping panels to one another. For example in FIG. 12 , a first panel 122 has a fastener 128 to secure it to first panel 122 ′. Similar fasteners are used to secure each of the second panels to one another (for example panel 124 to panel 124 ′ and panel 124 ′ to panel 124 ″).
[0036] Another embodiment of a protective covering 140 is illustrated in FIG. 13 . The protective covering 140 has a plurality of panels 142 , 144 , 146 , 148 , 150 , 152 that rest on one another in a vertical direction to cover a larger opening. Each of the panels 142 , 144 , 146 , 148 , 150 , 152 may be identical, or the last one, as illustrated in FIG. 13 may be slightly different. That is, the panels each have an S-shape, with a curved portion 154 at the top and 156 at the bottom so that they may attach to one another. However, it is also possible that panel 152 has only one curved portion 154 at the top and a flat portion 158 at the bottom for attachment to the structure 160 . While there are six panels shown in FIG. 13 , there may be more or fewer panels and they may be wider (top to bottom) or narrower than those illustrated.
[0037] It will be apparent to those skilled in the art that various modifications and variations can be made in the protective covering of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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A protective covering for an opening in a structure is presented that allows a single user to install and secure the covering. The protective covering may be easily and quickly installed without many tools or additional parts. The protective covering may also be installed from the inside or the outside, providing a more secure covering that may also be used while the owners of the structure are away for extended periods of time to prevent unauthorized entry.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a modular floating construction, comprising a plurality of floating bodies including platforms having removable latching or locking means.
[0002] Said removable locking means are coupled to one another by metal constructions, thereby providing floating boats, wharfs, working stages to be used on sea, rivers and water surfaces in general.
[0003] The floating constructions according to the invention, as suitably coupled to one another, may also be used for supporting barring dams, for controlling the diffusions through water of polluting liquids.
[0004] Those same floating constructions may moreover be used for testing cables and pipes, and have the main characteristic that they can adjust, depending on the contingent requirements, their floating force.
[0005] If the floating construction according to the invention is used for installing pipes and cables on deep waters, then it is necessary to provide a plurality of floating bodies, having corrosion resistant properties, and including supporting and releasing means for supporting and releasing the above mentioned cables and pipes, and further having high stability properties, even in a rough see condition.
[0006] The subject floating constructions can be coupled to one another, thereby providing wharfs for unloading goods from vessels and for supporting cables and pipes for connecting vessels and other boats to the ground, if harbours and mooring means are lacking in shallow waters.
SUMMARY OF THE INVENTION
[0007] Thus, the aim of the present invention is to provide such a modular floating construction which allows to adjust the floating force, thereby fitting the contingent requirements.
[0008] Within the scope of the above mentioned aim, a main object of the invention is to provide such a modular floating construction which can be quickly and easily assembled and disassembled, thereby providing composite floating constructions of the above mentioned type.
[0009] In particular, the engagement of the subject floating constructions is facilitated also in relationship to cables and pipes to be supported and optionally to be lowered into the water, thereby simplifying all the related operating steps.
[0010] Moreover, the subject floating construction, owing to its specifically designed structural features, is very reliable and safe in operation.
[0011] Yet another object of the present invention is to provide such a floating construction for supporting and testing or launching cables and pipes which can be easily made and which, moreover, is very competitive from a mere economic standpoint.
[0012] According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a floating construction, characterized in that said floating construction comprises at least a hollow floating body, made of a plastics material, and connectable to a metal construction, for connecting a plurality of plastics material floating elements, thereby providing modular floating constructions adapted to operate as decks, loading wharfs, working platforms, and also adapted to support cables and pipes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further characteristics and advantages of the present invention will become more apparent hereinafter from the following detailed disclosure of some preferred, though not exclusive, embodiment of a modular floating construction according to the invention, which is illustrated, by way of an indicative, but not limitative example, in the accompanying drawings, where:
[0014] FIG. 1 is a schematic perspective view schematically showing the floating body of the modular floating construction according to the present invention;
[0015] FIG. 2 is an elevation view showing that same floating body;
[0016] FIG. 3 is a top plan view of the floating body;
[0017] FIG. 4 shows a floating construction, supporting a pipe;
[0018] FIG. 5 shows the subject floating construction, as it is disengaged from the pipe;
[0019] FIG. 6 shows, on an enlarged scale, the coupling means for removably coupling a pipe, and related locking or latching removable means;
[0020] FIG. 7 shows, on an enlarged scale, the pipe disengaging operation;
[0021] FIG. 8 shows a side perspective view of the top portion of a structural element of the modular floating construction according to the invention;
[0022] FIG. 9 shows an exploded view of the constructional elements comprising a plastics material floating member and related metal members which can be coupled to the metal modular constructions associated with other adjoining floating components;
[0023] FIGS. 10 and 11 show two different views, respectively a perspective view and a top plan view, of a floating body constituting an integrating part of the modular floating construction according to the invention;
[0024] FIG. 12 is a cross-sectioned side perspective view, showing the plastics material floating body construction, constituting an integrating part of the present invention;
[0025] FIG. 13 is a perspective view of that same plastics material modular element shown in FIGS. 10 and 11 ;
[0026] FIG. 14 shows a further side perspective view of four floating plastics material elements associated with connecting metal constructions, which are mutually coupled to one another;
[0027] FIG. 15 shows a further perspective view of six plastics material floating elements, having coupling constructions and seen from the bottom;
[0028] FIG. 16 shows a further upper side perspective view of a plastics material floating element, and clearly shows the elliptical structure of the crossed tubular compartments, forming said plastics material floating body;
[0029] FIG. 17 shows an enlarged-scale partial perspective view, illustrating a section of an approximately elliptical compartment forming an integrating part of the plastics material floating element; and more specifically in FIG. 17 are clearly shown housing recesses for pivot pins allowing to connect a plastics material element to the fitting upper metal construction for coupling a plurality of modular floating constructions according to the invention;
[0030] FIG. 18 schematically shows the above mentioned pivot pins to be engaged in cavities formed in the plastics material floating body, a detail of which is shown in FIG. 17 ;
[0031] FIG. 19 is an upper side perspective view showing a detail of coupling elements for connecting the plastics material floating body to the top or upper constructional elements forming a fitting element for fitting and coupling structural elements, to be associated with one another thereby simultaneously providing an upper platform; and
[0032] FIG. 20 shows a floating construction including auxiliary ring elements for anchoring said floating construction.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] With reference to the number references of FIGS. 1-7 , the modular floating construction according to the invention, in an embodiment thereof designed for testing or launching pipes, which has been generally indicated by the reference number 1 , comprises a plurality of floating bodies 2 which have advantageously a substantially flat configuration and are made of a polyethylene material, by spin-molding operations.
[0034] The thickness of the used materials is so designed as to resist against the hydrostatic force.
[0035] The hollow floating body 2 is provided, at the bottom thereof, with resting or bearing projections 3 and, at the top thereof, with recesses 4 for engaging with a supporting framework 5 which will be disclosed in a more detailed manner hereinafter.
[0036] More specifically, the floating body 2 , as stated, is hollow and comprises a lead-in element 10 for introducing water thereinto, said lead-in element 10 having a check valve and a quick attachment or fitting.
[0037] Moreover, a counter-pressure valve 11 which is adjusted to a preset pressure level is moreover provided.
[0038] On the top surface of the floating body an air inlet 12 is arranged, which also comprises a quick type of coupling.
[0039] The framework 5 is advantageously provided with top cross members 6 , which are housed in their respective recesses 4 and comprise a plurality of vertical restraining elements 7 laterally engaging with the floating bodies 2 , thereby allowing to practically sling said floating bodies, to easily support them.
[0040] Said framework 5 comprises moreover coupling means for removably coupling a pipe, said coupling means being indicated generally by the reference number 20 , and comprising a plurality of recessed portions 21 , made of a metal sheet material, connected to a cross member 6 thereby defining a coupling seat for a pipe generally indicated by the reference letter T.
[0041] Removable latching means for removably coupling said pipe are moreover provided, said removable latching or locking means being adapted to be operated from outside and being advantageously arranged at said removable coupling means 20 .
[0042] The removable locking or latching means, in particular, comprise a hydraulic cylinder 30 , driving a locking pin 31 , engaging in a respective seat 32 defined on a gusset element 33 , directly welded on the pipe.
[0043] An outer central unit drives said hydraulic cylinder 30 which, by driving in turn said pin, allows to perform an unlocking operation, with the consequent launching of the pipe or cable to be lowered into the sea.
[0044] In this connection it should be apparent that it is further possible to provide other removable latching or locking means, without directly welding the gusset 33 on the pipe, and by using, for example, very simple systems, such as calandered metal sheet material ties, coupled by bolt elements.
[0045] Thus, the provision of the above mentioned water lead-in element 10 , allows to modulate or finely adjust the floating force, by introducing a desired amount of water.
[0046] The subject system, accordingly, provides the possibility of properly adjusting the floating force or pushing, by loading, through a pump system, the chamber defined inside the floating body.
[0047] Water is introduced through a water loading manifold, also including the above mentioned counter-pressure or check valve.
[0048] To empty the chamber, air is pumped from the air inlet duct 12 thereby providing a pressure in the inside of said floating body, allowing the check valve 11 to be opened, while allowing water to exit.
[0049] The air inlet 12 also operates as a bleeding element.
[0050] In other words, that same valve allows air to exit the chamber, as the vessel is filled-in by water.
[0051] In this connection it should be apparent that, if desired, it is possible to use the above disclosed inlets, to supply a polyurethane foam, thereby providing a stable floating characteristic.
[0052] It is moreover desired to point out that a main feature of the present invention is the provision of a plastics material body 2 including bulged ridges providing, the thickness being the same, said plastics material floating element, with a very high mechanical strength against impacts and a larger resistance against air or other gas pressures supplied into the duct arrangements coupled to each plastics material floating element.
[0053] With reference to FIGS. 8-18 , it should be apparent that the subject modular floating construction 75 comprises a floating body 50 , made of a plastics material, including a plurality of longitudinal recesses 54 for housing therein corresponding longitudinal bars 52 having anchoring brackets for coupling to the floating body 50 a plurality of longitudinal section members 51 , cooperating to form the metal material top platform 62 .
[0054] Said floating construction 75 comprises moreover a plurality of longitudinal elements 51 cooperating to form, jointly with said longitudinal bars 52 including corresponding anchoring brackets 74 , the top metal platform 62 applied to the plastics material floating body 50 .
[0055] Said top platform 62 comprises moreover a plurality of cross bars 53 , clearly shown in FIG. 9 .
[0056] The plastics material floating body 50 comprises moreover a plurality of throughgoing holes 55 .
[0057] The top metal platform 62 of the modular floating construction according to the invention comprises a plurality of longitudinal bars 51 , having corresponding brackets 74 matching with plate-like elements 73 rigid with the pins 72 , said pins 72 being received in corresponding cavities 71 formed in the plastics material floating bodies 50 .
[0058] More specifically, the longitudinal bars 51 are coupled to cross section members 81 cooperating to form the top platform 62 of the subject modular floating construction.
[0059] As shown, the plastics material floating body 50 has a complex construction including longitudinal floating compartments 59 and cross floating compartments 48 , of elliptical cross-sections, providing a complex construction having a great mechanical strength against the air pressure, the air being supplied inside the floating body 50 thereby suitably changing its floating force.
[0060] As a further feature, the modular floating construction 75 according to the invention can also comprise suitable side latching or locking elements 80 , comprising, for example, ring members, for anchoring the individual modular floating constructions 75 .
[0061] As shown, the plastics material floating body 50 shown in FIGS. 9 to 20 comprises, in its inside, a plurality of structural elements or ribs 57 , providing said floating body 50 with a great mechanical strength.
[0062] If desired, it is possible to use the above mentioned inlets to supply a polyurethane foam, thereby providing floating properties which will be stable in the time.
[0063] From the above disclosure it should be apparent that the invention fully achieves the intended aim and objects.
[0064] In particular, the invention provides a hollow floating body including a plurality of water and air inlets and outlets, which allows to change in a very broad range, the pushing force.
[0065] The invention, as disclosed, is susceptible to several modifications and variations, all coming within the scope of the invention.
[0066] Moreover, all the constructional details can be replaced by other technically equivalent elements.
[0067] In practicing the invention, the used materials, as well as the contingent size and shapes can be any, depending on requirements.
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A modular floating construction comprises one or more floating bodies having platforms including removable latching means, thereby providing floating stages, wharfs, working platforms to be used on water surfaces in general.
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The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license other on reasonable terms as provided for by the terms of contract No. N00014-84-K-0624 awarded by the Department of the Navy.
This application is a continuation of application Ser. No. 07/700,933, filed May 13, 1991 which is a continuation of application Ser. No. 07/348,704, filed May 8, 1989, both now abandoned, which is a division of application Ser. No. 07/149,236 filed, Jan. 29, 1988, now U.S. Pat. No. 4,906,840.
BACKGROUND OF THE INVENTION
The invention pertains to the field of Scanning tunneling microscopes, and more particularly, to the field of integrated versions of same.
Scanning tunneling microscopes were first invented by a team of researchers from IBM (Binnig and Rohrer). The basic concept of a scanning tunneling microscope is to place a very sharp, conducting tip having tip dimensions on the order of the size of 1 atom in diameter close to a conductive surface. If the tip is brought very close to a conductive surface, i.e., within the space of the diameters of several atoms, (approximately within 5 angstroms), a tunneling current flows between the tip and the surface. That is, the probability density function of electrons for atoms in the tip overlaps in space the probability density function of electrons for atoms on the surface. As a result, tunneling occurs in the form of electron current flow between the tip and the surface if a suitable bias voltage between these two conductors is applied.
The magnitude of the tunneling current is exponentially dependent upon the distance between the tip and the surface. If the distance between the tip and the surface increases by only 1 angstrom, the current is reduced by a factor of 10. Typically, 100 millivolts of bias voltage will provide 1 nanoampere of current for a tip to sample spacing of a few angstroms.
This tunneling current phenomenon can be used to take an image of the surface. To do this, the tip must be placed very close to the surface and must be moved in raster scan-like fashion across the surface while maintaining the relative distance between the tip and the surface. The tip must be moved up and down to follow the contour of the surface to maintain a relatively constant distance between the highest point on the surface and the tip. This distance must be accurately maintained to be within the tunneling overlap distance to maintain constant current flow. As the tip is scanned across the contour of the surface, an image of the surface contour may be built up by keeping track of the movements of the tip. Typically this process of tracking the tip movement is done by keeping track of the voltage applied across a piezoelectric transducer which moves the tip to maintain the constant distance between the tip and the surface. Typically the apparatus that controls the tip distance monitors the current flowing between the tip and the surface and controls a mechanical system to move the tip in such a manner as to stabilize the current flowing between the tip and the surface at some steady state value. Thus, changes in the current will result in changes in the distance between the tip and the surface so as to counteract the changes in the current and stabilize it at a steady state value. Thus, changes in the drive signals to the tip movement mechanism track changes in the surface contour as the height of the tip above the surface is adjusted to maintain constant current.
A collection of papers defining the state of the art in scanning tunneling microscopy is published in the IBM Journal of Research and Development, Vol. 30, No. 4, pages 353-440, July 1986. In an article entitled "Scanning Tunneling Microscopy" by Binnig and Rohrer at pages 355-369 of that journal, a scanning tunneling microscope is depicted in FIG. 2 using a piezoelectric tripod. This tripod consists of 3 piezoelectric rods of material joined at a junction; each rod expands and contracts along one of 3 Cartesian coordinate axes. The tip is mounted at the junction of the 3 rods. The tip is brought into proximity of the surface by a rough positioner. Thereafter the piezoelectric tripods are used to scan the tip across the surface to develop an image of that surface. The collection of papers in the IBM Journal of Research and Development shows scanning tunneling microscopy as being done with large scale apparatus.
One reference teaches an integrated form of a scanning tunneling microscope. This reference is European Patent Application Publication No. 0194323A1 published Sep. 17, 1986 based on European Application 85102554.4 filed Jul. 3, 1985. This patent application describes a scanning tunneling microscope integrated on a semiconductor chip into which slots are etched to form a center portion cantilever. The slots are etched to have mutually orthogonal directions to allow the center portion to perform movements in the X and Y direction under the control of electrostatic forces created between the stripes defined by the slots and their opposite walls. A protruding tip is formed on the center portion which is capable of being moved in the Z direction by means of electrostatic forces. Electrostatic forces are not ideal for tip movement to obtain maximum accuracy. Also, the integrated STM described in the European Patent Application cited above would be difficult to successfully fabricate.
Thus, a need has arisen for an integrated version of the scanning tunneling microscope using piezoelectric means for moving the tip.
SUMMARY OF THE INVENTION
According to the teachings of the invention, there is disclosed both an integrated piezoelectric transducer of novel construction and an integrated scanning tunneling microscope using this piezoelectric transducer for the necessary tip movement. The piezoelectric transducer uses bimorph technology.
In one embodiment of the piezoelectric transducer, a layer of spacer material which will later be removed, is placed over the surface of a silicon or other substrate. Thereafter, a layer of conductive material is formed on the spacer layer and patterned to form three separate electrodes. Then a layer of piezoelectric material is formed over the three electrodes and another layer of conductive material is formed over the layer of piezoelectric material. A second layer of piezoelectric material is then formed over the middle conductor. Finally, a third conductive layer is formed over the second piezoelectric material layer and is patterned to form three separate electrodes which are aligned with the three electrodes of the bottom-most conductive layer. Then a sharp, conductive tip is formed on the center electrode on the uppermost conductive layer. This tip is formed by evaporation deposition of a conductive material through a shadow mask. The evaporation deposition forms a cone of material of ever decreasing diameter on the center, top electrode. The ever-decreasing diameter results as the material landing on the shadow mask slowly closes off the hole in the mask above the point where the tip is being formed.
After the foregoing structure is formed, the sides of the piezoelectric material are etched away to form the bimorph lever. This etching is performed in such a manner that sufficient piezoelectric material is left on the sides to completely encase the center electrode. This etching of the piezoelectric material is done by first depositing a layer of titanium/tungsten metal and patterning this layer to act as an etch mask. This layer of metal is patterned using conventional photolithography techniques to define where the edge of the piezoelectric material is to be. After the metal etch mask is formed, the zinc oxide piezoelectric material is etched using the metal mask as a guide. If other piezoelectric materials are used which may be etched with good resolution, this step of depositing and forming a metal etch mask may be eliminated. Zinc oxide is a piezoelectric material which cannot easily be etched with good resolution. The step of forming the metal etch mask substantially improves the resolution which may be obtained in etching the zinc oxide material. "Resolution" as the term is used here is intended to specify the degree of control over the position of the edge of the zinc oxide.
After the piezoelectric material has been etched, the spacer material underlying the entire structure is removed. This spacer material is removed only up to the point where the cantilever bimorph is to be physically attached to the substrate. Removal of the spacer material causes the bimorph cantilever to extend out from its attachment point over the substrate with an air space between the bottom of the bimorph and the top surface of the substrate. This allows the bimorph to move up and down normal to the surface of the substrate by the effect of the piezoelectric material thereby allowing the tip to be moved. The existence of four pairs of electrodes and two layers of piezo material in this embodiment, allows three axis movement of the tip to be obtained.
To operate the structure just described so as to cause the tip to make raster scanning movements, various voltage combinations are applied to the four pairs of electrodes formed by the middle layer electrode and the outer electrodes on the bottom and top electrode layers. By suitably controlling the voltages applied to these four electrode pairs, the tip may be made to move along any of the three axes in a Cartesian coordinate system.
In alternative embodiments, two such bimorph structures each having two piezo layers but only two pairs of electrodes, formed as previously described, may be fabricated so as to extend out over the substrate from their attachment points and to intersect each other at a 90° angle and to be joined at the intersection. These two bimorphs may then be controlled in a similar manner to the manner described above for a single bimorph to move the intersection point along any of the three axes of a Cartesian coordinate system. In an alternative embodiment, two conductive tips may be formed at the end of the bimorph and the voltages applied to the electrodes may be manipulated so that the tip of the bimorph rotates to provide independent Z axis motion for each tip and synchronous X and Y motion for both tips.
An alternative, and preferred, embodiment of the method for forming the bimorph piezoelectric transducer structure described above, is to form the multilayer structure directly on a silicon substrate without any spacer material as described above but to free the bimorph cantilever from the substrate by etching through to the under surface of the cantilevered bimorph from the back side of the wafer.
A scanning tunnelling microscope according to the teachings of the invention may be made by using any of the processes described herein to manufacture a bimorph tip movement structure and then placing the tip sufficiently close to a conductive surface to be scanned such as by attaching to the substrate on which the bimorph is integrated another wafer containing the conductive surface to be scanned. Suitable known control circuitry may then be integrated on either substrate if it is of semiconductor material to sense the tunneling current and to control the voltages applied to the electrodes of the bimorph.
The scanning tunneling microscope structures in integrated form described herein have many potential applications including imaging at the atomic level, atomic scale lithography and mass storage. Mass storage systems of very high density can be formed using such a structure by defining a discrete number of "cells" within the raster scannable surface of a conductive plane formed adjacent to the tip. Each cell constitutes one memory location. Each memory location is written as a 1 or 0 depositing a molecule of sufficient size to be detected by the scanning tunneling microscope within each cell to form a 1 and not depositing such a molecule in the cell to form a 0. As the scanning tunneling microscope raster scans over such a surface, those cells wherein molecules are deposited are read as ones as the tip is forced by its control system to move away from the surface to maintain a steady tunneling current as the tip passes over the molecule. Essentially, the molecule forms a "hill" in an otherwise smooth surface. This hill causes the distance between the tip and the top of the molecule to decrease, thereby substantially increasing the tunneling current. The control system detects this increase and sends the appropriate voltages to the bimorph cantilever to cause the tip to move away from the surface sufficiently to bring the tunneling current back down to the constant level for which the system is calibrated. This movement of the tip or change in the voltages sent to the bimorph electrodes is detected and read as a logic 1. Other circuitry keeps track of the tip position and signals as each new cell is traversed. Thus, such a movement of a tip as it traverses a particular cell can be read as a 1 and lack of movement as it traverses another cell can be read as a 0. Such mass storage systems have the potential for tremendous information storage density because of the small, atomic scale dimensions involved.
Imaging applications of such a scanning tunneling microscope provide the ability to see the characteristics of surfaces on an atomic scale with greater resolution than has heretofore been attained. This allows the examination of such surfaces as semiconductor substrates during various stages of processing for research and development or quality control purposes. Vast numbers of other applications will be appreciated by those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is diagram of typical scanning tunneling microscope system.
FIG. 2(a) and 2(b) are a view of a prior art discrete, large scale scanning tunneling microscope invented by IBM
FIGS. 3-10 are successive cross sectional views along the transverse axis of the bimorph cantilever of the intermediate stages in a first process of fabrication of the preferred structure for an integrated single lever bimorph cantilever with tip for a scanning tunneling microscope according to the teachings of the invention.
FIG. 11 is a cross sectional view of the final scanning tunneling microscope preferred structure taken along the longitudinal axis of the bimorph cantilever.
FIG. 12 is a plan view of the one cantilever preferred bimorph structure according to the teachings of the invention.
FIG. 13 is a diagram of the four pairs of electrodes in the one cantilever bimorph used to explain how three axis motion is achieved.
FIG. 14 is a table of the various voltages that must be applied to achieve motion in any particular axis.
FIGS. 15-20 are cross sectional diagrams longitudinally through one bimorph of an alternative two bimorph piezoelectric transducer according to the teachings of the invention.
FIG. 21 is a transverse cross section of the bimorph construction in two bimorph embodiments.
FIG. 22 is a plan view of a two bimorph embodiment of the invention with no control circuitry integrated on the substrate.
FIGS. 23-33 are cross sectional views of intermediate stages in the preferred process for construction of an integrated piezoelectric transducer and scanning tunneling microscope having either the preferred structure shown in FIG. 10 or the two arm structure shown in FIGS. 20 and 22.
FIGS. 34(a) and (b) through 36(a) and (b) represent the types of X, Y and Z axis motion that can be achieved with single tip bimorphs having the structure shown in cross section in FIG. 10.
FIGS. 37(a) and (b) represent the types of rotational motion that can be achieved in two tip embodiments using a bimorph having the construction shown in FIG. 10 to provide independent Z axis motion and synchronous X and Y motion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Before discussing the details of the preferred and alternative embodiments of the integrated piezoelectric transducer, a scanning tunneling microscope (STM) using this transducer and methods for making these structures, it would be helpful to understand the teachings of the invention to explore the current state of the prior art in STM's. FIG. 1 depicts a prior art scanning tunneling microscope system which can be integrated according to the teachings of the invention. In FIG. 1, a conductive surface 10 having topographical features 12 and 14, etc., is scanned by a conductive tip 16. This tip is very narrow at its point, and preferably terminates in a single atom at the point 18.
The point 18 is scanned over the conductive surface 10 by a piezoelectric transducer 20. The purpose of this piezoelectric transducer is to scan the tip over the surface by defining a plurality of raster scan lines in the X-Y plane. The transducer 20 also moves the tip back and forth along the Z axis as the tip is scanned in the X-Y plane so as to maintain a distance between the tip 18 and the uppermost portion of the topographical feature over which the tip currently resides at a more or less constant distance. This distance is usually around 1 to 10 angstroms, and must be within the overlap region of the probability density functions of the electrons for the atoms in the tip 18 and the atoms in the uppermost regions of the topographical feature over which the tip currently resides. As long as the distance between the tip and the surface is within the overlap region of the probability density functions (tunneling range--usually less than 10 angstroms) and a bias voltage is applied across this junction, a tunneling current will flow between the tip 18 and the conductive surface. This tunneling current is symbolized by the arrow I T .
The magnitude of the tunneling current I T is exponentially related to the distance between the tip and the surface. The magnitude of the tunneling current will decrease when the distance becomes larger and increase when the distance becomes smaller. To cause this tunneling current to flow, a bias voltage is applied between the tip 16 and the conductive surface 10 by a bias voltage source 22. A current sensor 24 senses the magnitude of the tunneling current I T and outputs a feedback signal on line 26 which is proportional to the magnitude of the tunneling current. A feedback circuit in control system 28 receives this feedback signal and generates suitable piezotransducer driving signals on the bus 30 to cause the piezoelectric transducer to move the tip 16 in such a manner as to maintain the tunneling current I T at a relatively constant value. The control system 28 also generates suitable piezoelectric transducer driving signals on the bus 30 to cause the tip 16 to be raster scanned across the conductive surface.
FIG. 2 is a diagram of a typical scanning tunneling microscope prior art structure as developed by IBM and as discussed in the above cited IBM Journal of Research and Development. FIG. 2 shows the mechanical details of the structure. The microscope tip T is scanned over the surface of a sample S with a piezoelectric tripod (X, Y, Z) in FIG. 2(a). A rough positioner L brings the sample within reach of the tripod. A vibration filter system P protects the instrument from external vibrations. In the constant tunneling current mode of operation, the voltage V Z is applied to the Z piezoelectric element by means of the control unit CU depicted in FIG. 2(b). The control unit keeps the tunneling current constant while the tip is scanned across the surface by altering the control voltages V X and V Y . The trace of the tip generally resembles the surface topography. Inhomogeneities in the electronic structure of the sample's surface also produce structure in the tip trace. This is illustrated on the right half of the sample S as two surface atoms which have excess negative charge.
Process #1
Referring to FIG. 3 there is shown an integrated structure representing an intermediate stage after the first several steps in a process for making an integrated scanning tunneling microscope using an integrated piezoelectric transducer. Fabrication starts with a substrate 32. Preferably this substrate is silicon or some other substrate suitable for forming integrated electronic circuits. However, the substrate may be any other material which is chemically, mechanically and thermally compatible with the materials which will be formed on top of the substrate. It is preferable to make the substrate 32 of a semiconductor material so that the control circuitry which will be used to cause the tip movement via the piezoelectric bimorph can be formed on the same substrate as the bimorph itself.
The first step in the fabrication sequence is to deposit a spacer layer 34 under the portion of the bimorph that is to be cantilevered. The bimorph will be attached to the substrate at the end opposite the tip, so no spacer material is formed in this attachment region. This spacer layer will later be removed to provide a space between the uppermost surface (most positive Z coordinate) of the substrate 32 and the undersurface (most negative Z coordinate) of the piezoelectric bimorph which will be formed on top of the spacer layer 34. This will provide a clearance space for the piezoelectric bimorph to move along the Z axis. Preferably the spacer material is titanium, titanium/tungsten or polyimide. This spacer layer must be of a material such that it can be selectively etched without having the etchant attack the material of the substrate 32 or the material of the overlying electrode and piezoelectric material layers. This class of materials will be hereafter referred to as the class 1 group of materials. Any material which can be selectively etched without attacking the materials of the other layers will suffice for purposes of practicing the invention. Titanium/tungsten alloy (10% Ti: 90% W) is a class 1 material selectively etchable by hydrogen peroxide if the conductors are aluminum and the piezoelectric material is zinc oxide. Polyimide is another example of a class 1 material which can be selectively etched with an oxygen plasma. The thickness of the spacer layer 34 should be adequate to provide sufficient space for the bimorph to move in the negative Z direction.
Next, a layer of conductive material is deposited on top of the spacer layer. This layer of conductive material is photolithographically patterned and etched to form three electrodes 36, 38 and 40. The purpose of these electrodes will become clear later when the operation of the entire structure is detailed. Note, that although electrode 38 is shown to be more narrow than the electrodes 36 and 40 in the figures, in reality the electrodes 36, 38 and 40 are usually all the same size. This does not have to be the case however. The conductive layer from which the electrodes 36, 38 and 40 are formed is preferably of aluminum and is deposited to 0.1 to 1.0 μthickness. The electrodes 36 and 40 are patterned to be approximately 3 τ↓ 100 μ wide each.
Referring to FIG. 4, there is shown another intermediate stage in the fabrication of the integrated piezoelectric scanning tunneling microscope after the first layer of piezoelectric material has been deposited. After formation of the first three electrodes, the next step in the process is to deposit the first layer of piezoelectric material over the entire surface of the chip. This layer 42 is zinc oxide in the preferred embodiment of the structure and is deposited to 2μ thickness by reactive sputtering in an oxygen ambient. Methods for depositing zinc oxide are well known and are described in the following references which are hereby incorporated by reference Rozgonyi and Polito, Preparation of ZnO Thin Films By Sputtering of the Compound in Oxygen and Argon, Applied Physics Letters, pp. 220-223, Vol. 8, Number 9 (1966); Denburg, Wide-Bandwidth High-Coupling Sputtered ZnO Transducers on Sapphire, IEEE Transactions On Sonics and Ultrasonics, pp. 31-35, Vol. SU-18, No. 1, (Jan. 1971); Larson et al., RF Diode Sputtered ZnO Transducers, IEEE Transactions on Sonics and Ultrasonics, pp. 18-22 (Jan. 1972); Shiosaki et al , Low-Frequency Piezoelectric-Transducer Applications of ZnO Film, Applied Physics Lett., pp. 10-11, Vol. 35, No. 1, (Jul. 1, 1974); Khuri-Yakub et al., Studies of the Optimum Conditions For Growth of RF-Sputtered ZnO Films, pp. 3266-3272, Journal of Applied Physics, Vol. 46, No. 8 (Aug. 1975); Chen et al , Thin Film ZnO-MOS Transducer With Virtually DC Response. pp. 945-948, 1985 Ultrasonics Symposium of IEEE; Royer et al., ZnO on Si Integrated Acoustic Sensor, pp. 357-362, Sensors and Actuators, 4 (1983); Kim et al , IC-Processed Piezoelectric Microphone, pp. 467-8, IEEE Electron Device Letters, Vol. EDL-8, No. 10 (Oct. 1987). Next, a layer of conductive material 44 is deposited over the first piezoelectric layer 42. The purpose of this conductive layer is to form a center electrode between the two layers of piezoelectric material which will be used to form the bimorph. Preferably, the layer 44 is aluminum and is deposited to 0.1 to 1.0μ thickness. From this layer a center electrode is photolithographically formed to be approximately 10 to 200μ wide.
Referring to FIG. 5, there is shown another intermediate stage in the fabrication of the bimorph after the second piezoelectric layer has been deposited. This second piezoelectric layer 46 is zinc oxide in the preferred embodiment of the structure and is deposited to 2μ thickness. Next a layer of conductive material is deposited on top of the second piezoelectric layer 46. Preferably, this layer of conductive material is approximately 0.1 to 1.0μ thick aluminum. In some embodiments, an additional 1000 angstroms of gold is deposited on top of the aluminum. From this conductive layer, three electrodes 48, 50 and 52 are formed by photolithographic patterning. These electrodes are aligned with the locations of the electrodes 36, 38 and 40 and have the same widths as those electrodes. Preferably, the electrodes 48, 50 and 52 are deposited using lift-off techniques.
Referring to FIG. 6, there is shown an intermediate stage in the process of manufacture after the first few steps of the process of forming the tip on the center electrode 50 have been performed. Fabrication of metal cones by evaporation is not a new technique, but has been previously described by Spindt et al., J. Appl. Phys., 47, 5248 (1976). FIG. 6 depicts an alternative embodiment of the tip formation process using an integrated shadow mask.
Basically the process of forming a tip having sufficient sharpness is best done through the use of a shadow mask. In FIG. 6, this shadow mask is formed from layers which are deposited over the uppermost group of three electrodes 48, 50 and 52. In the preferred embodiment of the structure, a separate wafer is processed to form a shadow mask with alignment keys, and this separate wafer is placed over the structure shown in FIG. 5 by aligning the alignment keys on each wafer. The separate wafer and the structure of FIG. 5 are then processed to have lock and key physical characteristics such that the aperture in the shadow mask can be properly aligned over the center electrode 50. In the alternative embodiment shown in FIG. 6, the first step in forming the integrated shadow mask is to deposit a layer 54 of the class 1 spacer material Again, this layer 54 must be selectively etchable by an etchant which will not attack the material of the electrodes 48, 50 and 52, or the zinc oxide of the layers 46 and 42 The layer of the spacer material 54 need not be the same type of material as used in the spacer layer 34 However, the material of both of these layers must be within the class 1 group of materials. No patterning is performed on the layer 54, and it is allowed to cover the entire structure. Next, a layer 56 of a class 2 material, preferably copper, is deposited over the spacer layer 54. A class 2 material is any material which may be selectively etched by an etchant which will not attack the class 1 material used above and below it and which can be etched away after tip formation without etching the material of the tip. In the preferred embodiment of the structure, the spacer layer 54 is 1000 angstroms of titanium/tungsten alloy. The layer 56 of class 2 material is preferably 2 μ of copper. Next, a 5000 angstrom layer 58 of class 1 spacer material is deposited over the class 2 layer 56.
FIG. 7 shows the integrated structure at an intermediate stage during formation of the tip after etching of the spacer layer 58 and underetching of the class 2 layer 56. The formation of the tip is done by evaporation of a metal through a shadow mask aperture. This shadow mask aperture must be raised above the surface upon which the tip is to be formed so that a cone of material may be built up before the shadow mask aperture is closed off by the deposition of the material on top of the shadow mask In FIG. 7, the shadow mask is the layer 58 and the shadow mask aperture is the opening 60 in this layer The opening 60 is formed by using a selective etchant for the class 1 material of layer 58 and conventional photolithographic techniques. The aperture 60 is defined to be 1-2 μ and is centered over the center of the electrode 50. Generally, the size of the aperture 60 should be much smaller than the size of the middle electrode 50. If the class 1 material of layer 58 is titanium/tungsten alloy, a suitable etchant for this selective etching step would be hydrogen peroxide.
After the aperture 60 is etched, the copper layer 56 must be etched back so as to underetch the perimeter of the aperture 60. The purpose for this underetching step is to provide clearance space for the walls of the tip cone which is to be formed later. The underetching step of the class 2 material of layer 56 is performed using a selective etchant which only attacks the class 2 material. If layer 56 is copper, this etch is performed using the aperture 60 as a mask and using a mixture of nitric acid, hydrogen peroxide, and water in a ratio of 10:1:100, respectively. That is, the etchant is 10 parts HNO 3 to 1 part H 2 O 2 to 100 parts H 2 O.
Referring to FIG. 8, there is shown the state of the structure in the intermediate stage of construction after formation of the tip but before removal of those layers which were formed in the process of forming the tip. Prior to the evaporation deposition of the tip material, a third etch step is performed to selectively etch through the class 1 material of layer 54 to form an aperture over the center electrode 50. In some embodiments, a cleaning step will then be performed to clean the surface of the electrode 50 to prepare it for tip deposition. This is done to better insure adhesion of the tip material to the electrode 50. The selective etching of the layer 54 is performed using a timed liquid etch or plasma etch to expose the top surface of the electrode 50. This etching step also etches a little of the layer 58 and all of layer 54 down to the electrode 50. For this reason, the layer 58 should be formed at least twice as thick and preferably 3 times as thick as the layer 54. A timed sputter etch is used to clean the surface of electrode 50 if needed. Where the boundary of the aperture in the layer 54 is relative to the boundary of the aperture in the layer 56 depends upon whether a liquid or plasma etch is used to etch the layer 54. The boundary of the aperture in the layer 54 will be colocated with the boundary of the aperture in the layer 56 for liquid etches and will be approximately located with the boundary of the aperture 60 in the layer 58 if a plasma etch is used.
Next, the tip 66 is formed. In the preferred embodiment of the structure, this tip is formed by evaporation in vacuum of tantalum or some other class 3 material. Any other material can be used for the tip 66 if it has the characteristics of a third class of materials hereafter defined. A class 3 material must be such that it does not oxidize appreciably in air and it must be such that it will not be etched by the etchant used to selectively etch the class 2 material of layer 56. Tantalum is such a material if copper is selected for the layer 56. Other possible materials for the tip would be aluminum coated with a noble metal by evaporation. Alternatively, the tip can be a noble metal standing alone, or any other conductor that can be selectively etched in the manner described above.
The evaporation of the class 3 material 62 from a point (approximately 1-5 mm) located far (approximately 10 cm) above the surface results in the formation of the layer 64. Note that as the evaporation continues through the aperture 60, the aperture in the layer 64 slowly decreases in diameter as evaporation continues due to condensation of the evaporated material on the sidewalls of the aperture. As the diameter of the aperture in the layer 64 continually decreases, so does the diameter of the cone of material in the tip 66 being formed beneath this aperture. When the aperture in the layer 64 finally closes itself off, formation of the tip 66 is complete, and a very sharp tip (tip radius less than 1000 angstroms) will have been fabricated.
Referring to FIG. 9, there is shown a cross section of the structure at an intermediate stage in the construction after lift-off of the shadow mask layers and deposition of a zinc oxide etch mask layer. Following the processing steps described with reference to FIG. 8, it is necessary to remove the layers 54, 56, 58 and 64 so as to expose the tip 66. This is done using a lift-off etch to remove the class 2 material of layer 56. This lift-off etch removes all the layers above layer 54, i.e., the class 2 layer 56, the class 3 layer 64 and the class 1 layer 58.
Next, it is necessary to etch the piezoelectric layers 46 and 42 to define the sidewalls of the bimorph cantilever beam. This is done by photolithographically patterning the remaining layer 54 to serve as an etch mask for the zinc oxide as described previously. Layer 54 is patterned to have the configuration shown in FIG. 9. Note that the edges 70 and 72 of this layer are located along the X axis outside of the edges 74 and 76 of the metal electrode layer 44. The reason for this location is to insure that the edges 74 and 76 of the middle electrode are completely encased in the zinc oxide of the layers 46 and 42. The purpose for this is to prevent leakage currents and arcing between the electrodes 36, 40, 44, 48 and 52 which would lower the breakdown voltages and prevent the device from operating at high voltages. The purpose of formation of the etch mask 68 is to improve the resolution of the etching of the piezoelectric layers 42 and 46. Etching of piezoelectric material such as zinc oxide using photoresist provides very bad resolution as to the exact location of the edge of the piezoelectric material relative to the edge of the photoresist. It has been found that substantial improvements in the certainty of the location of this edge can be made by first forming an etch mask of the class 1 material such as titanium/tungsten alloy and then using this etch mask to guide the etching of the piezoelectric material. Thus, after the layer 68 is formed, a solution of 15 grams NaNO 3 , 5 ml HNO 3 and 600 ml H 2 O is used to etch the piezoelectric layers 46 and 42 back to the approximate location of the edges 70 and 72.
After the tip is exposed, and the piezoelectric layers are etched, the spacer layer 34 is selectively etched away to free the cantilever.
FIG. 10 shows in cross section the preferred final piezoelectric bimorph transducer structure in integrated form according to the teachings of the invention after selective etching of the spacer material layers 34 and the etch mask layer 54. Note the aperture 78 formed by the removal of the spacer layer 34. It is this void which allows the tip 66 to move along the Z axis under the influence of the forces generated by the piezoelectric material.
FIG. 11 shows a cross sectional view of the bimorph cantilever taken in the Y-Z plane, whereas the cross section of FIG. 10 is taken in the X-Z plane. A plan view of the bimorph cantilever is shown in FIG. 12 looking down the Z axis at the X-Y plane. FIG. 12 shows the locations of the sections taken in FIGS. 10 and 11 as the section lines 10--10' and 11--11', respectively. Note in FIG. 11 the cantilevered nature of the bimorph structure, the bimorph being attached to the substrate 32 only in the area 80. The relative dimensions in FIG. 12 may be not truly indicative of an actual design which would be commercially employed. Bonding pads 89, 91 and 93 are coupled by conductive paths to the two electrode pairs comprised of electrodes 48, 36 and 44. Bonding pads 97, 99 and 101 are coupled by conductive paths to the two electrode pairs comprised of electrodes 52, 40 and 44 Bonding pad 95 is coupled by conductive paths to both the electrodes 50 and 38 and the tip 66. In embodiments where the control circuitry is integrated on the substrate 32, the bonding pads shown in FIG. 12 can be eliminated.
Necessary Additional Elements Needed For An STM
Referring again to FIG. 11, there are several additional elements of a scanning tunneling microscope system which are necessary for converting the cantilever bimorph piezoelectric transducer shown in FIG. 11 to a system having multiple commercial applications . An overlying wafer 82 having a conductive surface 84 is formed with a cavity 86 such that the wafer 82 may be physically attached to the substrate 32 with the conductive surface 84 overlying and within several microns of the end of the tip 66, such that the tip can be brought up to the surface 84 by bending of the bimorph. In the preferred embodiment of the scanning tunneling microscope (STM) structure, the wafer 82 may be Pyrex or silicon, but, in alternative embodiments, the wafer 82 may be any other material which is mechanically, thermally, and chemically compatible with the materials used in the rest of the structure. Preferably, the material of the wafer 82 should be such that a good bond may be made between the wafer 82 and the substrate 32, and such that suitable convenient fabrication techniques are known which may be used to form the cavity 82 and to attach a conducting surface 84 to the wafer 82. In still other alternative embodiments, the wafer 82 may be itself a conductive material such that no separate conductive surface 84 needs to be attached. In such embodiments, the cavity 86 should be such that the portion of the wafer 82 of interest is scanned by the tip 66. Also, the electrodes 36, 38, 40, 44, 48, 50 and 52 will have conductive pathways formed through the piezoelectric layers and across the surface of the substrate 32 to bonding pads such that the appropriate voltages may be applied to these electrodes to cause the tip 66 to scan in the desired manner. If these conductive pathways pass between the surface of the substrate 32 and the mating surface of the wafer 82, the materials for these two structural elements must be selected such that the conductive pathways may be properly formed.
In some embodiments, the control circuitry to supply the bias current to the tip 66 and to control the voltages applied to the various electrodes will be integrated on the substrate 32. The block 88 represents the integration of such known circuitry on the substrate in known manner. The position of the block 88 is illustrative only since this circuitry may be integrated on the side of the substrate, in a recess in the substrate, or on the reverse side of the wafer opposite the side from which the bimorph cantilever is formed. It is preferred to integrate the circuitry at a location to minimize the complexity of routing the various signals and control voltages to the appropriate nodes of the circuit.
The structure shown in FIG. 11 can be used for mass storage, microscopic photolithography, imaging and other commercial applications.
Referring to FIG. 13, there is shown a schematic diagram of a cross section through the bimorph cantilever to illustrate how the various electrodes are operated to cause movement of the cantilever in the Cartesian coordinate system. The cross section of FIG. 13 has the same orientation as the cross section 10--10' in FIG. 12. The vectors marked 1, 2, 3 and 4 in FIG. 13 represent the electric field vectors existing between the four pairs of electrodes. The electric field vector 1 represents the field between the electrode 52 and the center electrode 44. The electric field vector 2 represents the field between the center electrode 44 and the outer electrode 40. The electric field vector 3 represents the field between the electrode 48 and the center electrode 44, and the electric field vector 4 represents the field between the center electrode 44 and the outer electrode 36. In each case, the electric field is directly proportional to the potential difference applied to the pair of electrodes bounding the region of interest.
The nature of the piezoelectric zinc oxide is such that if a field is applied in the Z direction (which is along the crystalographic C-axis of the material) that causes the material to contract along that axis, and the material simultaneously expands along both the X and Y axes. Only expansions or contractions along the Y axis cause any bending of the bimorph. Hence, the following discussion refers to Y-axis motion only.
Referring to FIG. 14, there is shown a table of the desired movements in the Cartesian coordinate system having the axes oriented as shown to the left of FIG. 13, said table correlating these desired movements to relative expansions in the piezoelectric material in accordance with the relationships given on the right half of the table. The manner in which the table of FIG. 14 is interpreted is as follows. If it is desired to cause movement of the bimorph of FIG. 13 in only the negative X direction, it is necessary to charge the electrodes 52 and 44, and 44 and 40, respectively, such that the relative Y-axis expansion of the piezoelectric material in the layers 46 and 42 between these two pairs of electrodes is equal. Further, it is necessary to charge the electrodes 48 and 44, and 44 and 36 such that the Y-axis expansion of the piezoelectric material in the layers 46 and 42 between these two pairs of electrodes is also equal, but such that the Y-axis expansion between the electrode pairs 48 and 44, and 44 and 46, respectively, is less than the expansion between the electrodes 52 and 44, and 44 and 40, respectively. In other words, if one thinks of the vectors marked 1-4 in FIG. 13 as the relative magnitude of the Y-axis expansion of the piezoelectric material in the layers 46 and 42 in the localized areas through which these vectors pass, then to obtain negative X movement of the bimorph, it is necessary that the expansions in areas 1 and 2 be equal and greater than the expansions in areas 3 and 4. This causes movement of the bimorph in the negative X direction in the same mechanical fashion as a bimetallic strip works where one layer of metal in the bimetallic strip expands less than the other layer of metal. This causes forces which tend to cause the strip to bend toward the strip which expands less. From FIG. 14, it is seen that for positive X expansion the situation is exactly opposite as the situation previously described. That is, the expansions in the areas 3 and 4 are equal and exceed the expansions in the areas 1 and 2. Likewise, for negative Y movement, i.e., movement into the page of the tip 66, it is necessary to charge the electrodes 48, 52, 44, 36 and 40 such that the piezoelectric material in regions 1-4 all contract an equal amount. This contraction is signified as expansion less than zero. For positive Y movement, it is necessary to charge the same electrode such that regions 1-4 all expand by the same amount which is signified by an expansion greater than zero. For positive Z movement, it is necessary to charge the electrodes such that regions 2 and 4 expand equally and greater than the expansion in regions 1 and 3. Likewise, for negative Z movement, it is necessary to charge the electrode such that regions 1 and 3 expand an equal amount and greater than the expansion in regions 2 and 4.
It is possible to obtain any desired movement in the Cartesian space defined by the 3 axes coordinate system to the left of FIG. 13 by superimposing these relationships from any one axis upon the relationships for another axis. That is, if both negative X and positive Y movement is simultaneously required, the relationships from these two lines of the table of FIG. 14 are superimposed such that all four regions are expanded equally by an amount A to obtain the desired Y component with an additional expansion of regions 1 and 2 by an amount B over the expansion of regions 3 and 4 to obtain the desired negative X component. Note that electrode 50 only serves as a signal connection to the tip 66. The bottom electrode 38 is charged with the same bias voltage applied to the top center electrode 50 and the tip to eliminate any spurious, parasitic movements caused by expansion or contraction in the piezoelectric layer 46 under the center electrode 50. Any such movement is cancelled by the movements in the layer 42 caused by the charge on the bottom center electrode 38.
Process #2
Beginning at FIG. 15, the fabrication of the two arm bimorph embodiment of a piezoelectric transducer according to the teachings of the invention is shown. Note that FIGS. 15 through 20 show a view of one bimorph lengthwise similar to the view shown in FIG. 11 of the transducer built according to the previously described process.
Referring to FIG. 15, there is shown an intermediate stage in the process of making an arm of a two arm bimorph using a backside etch technique. A substrate 92 is chosen which is preferably a semiconductor, but which may also be, in alternative embodiments, other materials capable of being micromachined. Semiconductor is desirable for the substrate so that control circuitry may be integrated on the same die as the bimorph itself. The first step in the process is to grow a 500 angstrom thick layer of silicon dioxide 94. Next, a 900 angstrom thick layer of nitride (Si 3 N 4 ) is grown, and conventional photolithography techniques are used to define and etch a hole through the oxide layer 94 and nitride layer 96 to expose the surface of the substrate 92 as shown at 98.
Referring to FIG. 16, there is shown another intermediate stage in the construction of a two arm bimorph after etching of the cavity. After defining the location of the aperture in the silicon dioxide and nitride layers as shown in FIG. 15, a KOH etch is used to etch a 350μ deep trench in the substrate 92, using the nitride layer as an etch mask. This trench is shown at 100. Thereafter, the nitride layer 96 is stripped to leave only the silicon dioxide layer 94. Alignment marks are then patterned into side A to allow alignment to the pattern on side B (see FIG. 15).
FIG. 17 shows another intermediate stage in the process after deposition of the first electrode layer. The next step is to deposit 0.1 to 1.0μ of aluminum and to pattern it to form the electrode shown at 102.
FIG. 18 shows another intermediate stage after deposition of the first piezoelectric layer and formation of a center electrode. After forming the electrode 102, a layer 104 of piezoelectric material is deposited. This layer is 2μ of zinc oxide or some other piezoelectric material Next, a 0.1 to 1.0μ layer of aluminum is deposited and patterned and etched to form the center electrode 106.
Referring to FIG. 19, there is shown an intermediate stage in the construction of the two arm bimorph after the second layer of piezoelectric material and the top electrode has been formed. After forming the middle electrode 106, 2μ of piezoelectric material are deposited in a layer 108. This layer is zinc oxide or some other piezoelectric material. Next, 0.1 to 1.0μ of aluminum and 1000 angstroms of gold are deposited over the piezoelectric layer 108. This layer of conductive material is then patterned and formed using lift-off techniques into the top electrode 110 and a tip electrode 112.
Referring to FIG. 20, there is shown another intermediate stage in the construction of the two arm bimorph after the tip has been formed and the structure has been underetched to free the bimorph. The process for forming the tip 114 is the same as described with reference to FIGS. 3-10. After the tip is formed, the zinc oxide is patterned and etched to form the edge 116. This process is done using the same class 1 etch mask material as was used in the process described with reference to FIGS. 3-10. Finally, a plasma etch is used to etch through the remaining substrate 92 to the silicon dioxide layer 94 to free the bimorph arm from attachment to the substrate 92 along the area 118.
FIG. 21 shows a cross section through the bimorph of FIG. 20 along the section line 21--21' in FIG. 20. As can be seen from FIG. 21 only two pairs of electrodes exist in the bimorph of FIG. 21. These two pairs of electrodes are the electrode 110 and the electrode 106, and the electrode 106 and electrode 102, respectively. Those skilled in the art will appreciate that this structure will allow the bimorph to bend up and down along the Z axis and expand or contract longitudinally along the X axis.
In order to get 3 axis Cartesian coordinate movement, a second arm having the structure shown in FIGS. 20 and 21 must be formed and joined to the bimorph of FIGS. 20 and 21 at the location of the tip 114. A plan view of the structure of this bimorph arrangement is shown in FIG. 22.
Referring to FIG. 22, the section line 20--20' indicates the position of the section through the structure of FIG. 22 as shown in FIG. 20. In the structure shown in FIG. 22, two bimorph arms, 116 and 118, extend from the substrate 92 at right angles joined at the approximate location of the tip 114. The bimorph 116 can move the tip 114 up and down along the Z axis and longitudinally along the X axis. The bimorph 116 can move the tip up and down along the Z axis and longitudinally along the Y axis. The bimorph 118 has its three electrodes 110, 106 and 102 coupled respectively to the bonding pads 120, 122 and 124. These connections are made via electrical conductors 126, 128 and 130, which are photolithographically formed simultaneously with the electrodes 110, 106 and 102 on the surface of the substrate 92. The tip 114 is coupled by an electrical conductbr 132 to a bonding pad 134. The corresponding three electrodes of the bimorph 116 are coupled to bonding pads 136, 138 and 140. In alternative embodiments, the circuitry to drive bias voltages onto the six electrodes to cause movement of the tip and to bias the tip 114 with a correct voltage could be integrated on the substrate 92 thereby eliminating the need for the bonding pads shown at the bottom of FIG. 22. In such an embodiment, bonding pads would be present for supply of power to the circuitry used to bias the tip and drive the electrodes.
Process #3--Preferred
The process described below is preferred to make either the one arm piezoelectric transducter having the structure of FIG. 10 or the two arm bipod piezoelectric transducer shown in plan view in FIG. 22 and in cross section in FIG. 20. Referring to FIG. 23, there is shown an intermediate stage in the preferred process for manufacturing a scanning tunneling microscope. The first step in the process is to clean a [100] silicon wafer of 380 micron thickness with a standard acid clean. The details of this cleaning process are given in Appendix A which is a detailed process schedule for the preferred process. Next, a layer 136 of silicon dioxide is thermally grown to a thickness of 5000 angstroms. Then, a layer 138 of silicon nitride is deposited to 1000 angstroms thickness over the silicon dioxide using low pressure chemical vapor deposition (LPCVD).
Referring to FIG. 24, there is shown the next stage in process after etching the backside pit. To free the bimorph cantilever to be formed later in the process, a backside etch is used. The first step in this process is to etch a pit in the backside Negative photoresist (not shown) is applied and patterned to define the location of the pit. An oxygen plasma etch is then used to remove any remaining scum from the opening in the photoresist where the pit is to be formed. The details of this plasma etch are given in Appendix A. Next, the nitride layer 138 is etched using an SF 6 and F13B1 plasma etch at a ratio of 1:1. Then, the oxide layer 136 is etched using a 6:1 buffered oxide etch solution (BOE). Following these two etch steps, the remaining photoresist (not shown) is removed and the wafer is cleaned using the process detailed in the appendix. Then 340 microns of silicon from the substrate 140 are etched away using the nitride/oxide layers as an etch mask. This etch is performed using a 30% KOH etch at 80 degrees C. The wafer is then rinsed in a 10:1 H 2 0:HCl solution, followed by a rinse in deionized water. This leaves the pit 142.
The substrate 140 has a polished front surface 144. Alignment marks are etched in this surface to facilitate the alignment of the various patterning steps to one another. FIG. 25 shows the wafer after this alignment mark 146 has been etched. The procedure for forming these alignment marks starts by patterning photoresist to define the positions of the alignment marks 146. Then an oxygen plasma etch is used to descum the openings and the nitride layer 138 and the oxide layer 136 are etched using the same procedure defined above in describing FIG. 24. A deionized water rinse and nitrogen ambient dry cycle are performed followed by etching of 3 microns of silicon using a 1:1 SF 6 :C 2 ClF 5 plasma etch. The wafer is then cleaned in accordance with the procedure outlined in Appendix A, and the remaining photoresist is removed. The layer of nitride 138 is then stripped using concentrated H 3 P0 4 at 165 degrees C. for 1 hour followed by a deionized water rinse and a nitrogen ambient drying cycle.
The next stage is shown in FIG. 26. To deposit the bottom electrode 148, the pattern of the electrode is defined with a positive resist liftoff process. Then the metal of the electrode is deposited by electron-beam evaporation deposition of 1000 angstroms of aluminum at room temperature. The excess aluminum is lifted of by soaking the wafer in hot acetone. The wafer is then rinsed in fresh acetone, methanol and deionized water and dryed in a nitrogen ambient.
FIG. 27 defines the next stage in the process. After deposition of the lower electrode, it is necessary to deposit the piezoelectric layer. This is done by first sputter cleaning the surface for 30 seconds and electron beam evaporation deposition of 1000 angstroms of silicon dioxide 150 on the substrate while holding the substrate at a temperature of 200 degrees C. Next, a 2 micron layer 152 of zinc oxide is sputter deposited using a zinc target in 5:1 O 2 :Ar gas ambient at 30 mTorr. During this process, the substrate is held to 300 degrees C. Then, a 1000 angstrom layer 154 of silicon dioxide is deposited over the zinc oxide by E-beam evaporation with the substrate at 200 degrees C.
FIG. 28 shows the intermediate stage in the process after the middle electrode is formed. To deposit the middle electrode 156, the pattern for the electrode is defined using mask #4 and positive resist and a liftoff technique. Next, a 1000 angstrom layer of aluminum is deposited by electron beam evaporation using a room temperature wafer holder. The excess aluminum is then lifted off by soaking the wafer in hot acetone. The wafer is then rinsed in fresh acetone, methanol and deionized water followed by a drying cycle in nitrogen ambient.
FIG. 29 shows the stage of the process after the upper oxide layers have been deposited. The first step in this process is to sputter clean the wafer for 30 seconds. Next, 1000 angstroms of silicon dioxide 158 are E-beam evaporation deposited with the substrate held at 200 degrees C. The top layer of piezoelectric material 160 is formed by depositing 2 microns of zinc oxide using a zinc target in a 5:1 mixture of oxygen and argon at 300 mTorr with the substrate at 300 degree C. Finally, a 1000 angstrom layer 162 of silicon dioxide is E-beam evaporation deposited over the zinc oxide with the substrate at 200 degrees C.
FIG. 30 shows the state of the wafer after the top electrode is formed. The top electrode 164 is formed by defining the pattern using a positive resist liftoff process. Then 500 angstroms of aluminum are deposited using a room temperature wafer holder and E-beam evaporation. This deposition is followed by an E-beam evaporation deposition of 500 angstroms of gold using a room temperature wafer holder. The excess gold and aluminum are then lifted off by soaking the wafer in hot acetone. The wafer is then rinsed in fresh acetone, methanol and deionized water and dryed in a nitrogen ambient.
FIG. 31 shows the wafer after the oxides have been patterned. The first step in this process is to sputter deposit 3000 angstroms of titanium/tungsten using an unheated wafer holder. Then the pattern for the oxide is defined in the titanium/tungsten layer which is to be used as an etch mask. This is done by defining the desired pattern in photoresist deposited on the titanium/tungsten and etching the titanium/tungsten layer using 30% H 2 O 2 for 30 minutes at room temperature. The wafer is then rinsed in deionized water and dryed in a nitrogen ambient. Patterning of the oxides then begins with etching of the top silicon dioxide layer 162 using 6:1 buffered oxide etch, followed by a deionized water rinse. The upper zinc oxide layer 160 is then etched in a solution comprised of: 15 grams of NaNO 3 , 5 ml HNO 3 , 600 ml H 2 O followed by a deionized water rinse. The middle layer 158 of silicon dioxide is then etched in the same manner as the layer 162, and the bottom layer 152 of zinc oxide is then etched using the same solution makeup as was used to etch the top layer 160. The bottom layer of silicon dioxide 150 is then etched using the same solution makeup used to etch the other layers of silicon dioxide. The wafer is then rinsed in deionized water and dryed. Next, 3 microns of silicon are removed from the top of the wafer in regions where all upper layers have been removed to expose the silicon substrate. This is done using a 1:1 SF 6 :C 2 ClF 5 plasma etch. The wafer is then cleaned and the resist is stripped using acetone, methanol and deionized water. The remaining titanium/tungsten etch mask is then removed in 30% H 2 O 2 for 30 minutes at room temperature. The wafer is then rinsed in deionized water and dryed.
After the oxide layers are etched, the bonding pad metal is deposited by defining the pattern by a positive photoresist liftoff process. The metal is the deposited using E-beam evaporation of 1 micron of aluminum using a room temperature wafer holder. The excess aluminum is then lifted off by soaking the wafer in hot acetone. The wafer is then rinsed in fresh acetone, methanol and deionized water and dryed.
Next, the wafer side B is scribed using a diamond-tipped saw.
FIG. 32 shows the wafer after the shadow mask for tip formation has been put into place and the tip deposition has taken place. First, the wafer is sputter cleaned for 30 seconds. Then, a separate wafer is fabricated to have the cross section shown in FIG. 32. This wafer has an aperture 166 formed therein and has alignment marks that match the alignment marks 146. The wafer of the shadow mask 168 is then attached to the substrate 140 with alignment marks matched so as to locate the aperture 166 over the desired location on the top electrode 164 for the tip 168. After, the shadow mask is in place, 5-10 microns of the desired tip material, e.g., niobium or tantalum, are deposited through the aperture 166 to form the tip 168. Note, that in the preferred embodiment, the structure of FIG. 32 will be formed at multiple locations on the wafer, and only one shadow mask 168 will be used with multiple apertures at all the desired tip locations for all the cantilevers. Finally, the shadow mask is carefully removed so as to not damage the tips.
Next, the cantilevers are separated from the substrate along part of their length. FIG. 33 shows the structure after this process has been performed. Separation is accomplished by depositing 10 microns of positive resist on side A of the wafer to protect the structure just described. The wafer is then subjected to a backside etch to etch through the remaining silicon membrane at the bottom of the pit 142 by subjecting side B of the wafer to a 3:1 SF 6 :C 2 ClF 5 plasma etch. The details of this etch are specified in Appendix A. The photoresist is then stripped using acetone, methanol and an air dry cycle. The individual die are then separated by cracking the wafer along the scribe lines.
The presence of the silicon dioxide layer 136 has been found to promote better growth of the aluminum layer 148 which also improves the growth of zinc oxide layers 152 and 160. It also allows conductive paths to be formed beneath the cantilever without being shorted out by the metal of the layer 148. The presence of the silicon dioxide layers 150 and 158 promotes better growth of the zinc oxide layers 152 and 160. The presence of the silicon dioxide layers 154 and 162 aids in balancing stresses in the cantilever which can build up during the deposition processes of forming the cantilever. That is, the same stresses will build up in the silicon dioxide layers 154 and 162 when they are deposited as build up in the silicon dioxide layers 150 and 158 when they are deposited. Accordingly, the stresses are balanced. Also, the silicon dioxide layers separating the pairs of electrodes increases the breakdown voltage. In alternative embodiments, the silicon dioxide layers may be omitted or other materials can be substituted.
The preferred method just described can be used to make either the "one-arm" or bipod type of piezoelectric transducer. The principal difference between these two different structures is in the number of electrode pairs that are formed inside each integrated cantilever. The one arm type of bimorph needs to have at least four pairs of electrodes formed to obtain 3 axis movement. If the one arm type of integrated transducer is to be used for a scanning tunneling microscope, 6 pairs of electrodes must be formed so that electrical connection can be made to the tip and the spurious piezo effects by this tip electrode can be cancelled out. For a two arm bipod type of transducer, only two pairs of electrodes need be formed in each bimorph arm. Obvious modifications to the above described process for the steps of forming the top electrode 148 and the bottom electrode 164 can be made depending upon the type of integrated piezoelectric transducer to be fabricated.
Referring to FIGS. 34(a) and (b) through 36(a) and (b) there are illustrated the movements which may be achieved with a one arm bimorph integrated piezoelectric transducer with the electrode structure shown in FIG. 10. The (a) and (b) illustrations of each figure depict both the positive and negative movements on the associated axis. FIG. 37(a) and (b) illustrate the type of rotational movement which may be achieved for two tip embodiments to have independent Z-axis movement for each tip. The tips move together along the Y and X axes however.
Typical performance parameters are as follows. If a dipod structure is considered with aluminum electrodes one micron thick and zinc oxide layers which are two microns thick, and the legs are each 1000 microns long and 100 microns wide, then the bipod will be able to move the tip 20 angstroms per volt in the X and Y axes and 0.6 microns per volt in the Z axis. The breakdown voltage is 30 volts and the scannable area is 600 angstroms by 600 angstroms or 360,000 square angstroms. If a single arm cantilever bimorph with the same dimensions as given in this paragraph is considered, 200 angstroms per volt of movement in the X axis and 20 angstroms per volt in the Y axis can be acheived. Movement of 0.6 angstroms per volt in the Z axis can be achieved. Thus, the scannable area for the single arm bimorph is 10 times larger than the dipod since the X axis movement is ten times greater per volt. The bimorph design must be such that the tip can be moved within tunneling range of the conductive surface for STM applications.
Although the invention has been described in terms of the preferred and alternative embodiments detailed herein, those skilled in the art will appreciate many modifications which may be made without departing from the spirit and scope of the invention. All such modifications are intended to be included within the scope of the claims appended hereto.
Preferred Planar STM Process
1. Deposition of mask materials
1a. Clean 380μm thick (100) wafer using standard acid clean***
1b. Thermally grow 5000 Å SiO 2
1c. Deposit 1000 Å Si 3 N 4 using LPCVD
2. Etch KOH pits from backside (rough surface, side B)
2a. Using mask #1 and negative photoresist, define KOH squares
2b. Oxygen plasma* for 1 min to `Descum` openings
2c. Etch Si 3 N 4 using SF 6 and Fl3Bl (1:1) plasma etch
2d. Etch SiO 2 layer using 6:1 buffered Oxide Etch (BOE)
2e. Strip photoresist and clean wafer**
2e. Etch 340 μm of silicon from backside using 30% KOH at 80° C.
2f. Rinse wafer using 10:1 H 2 O:HCl solution
2g, Rinse in de-ionized water (DI) then dry in N 2
3. Etch Alignment marks on frontside (polished side, side A)
3a. Using mask #2 and positive resist, define alignment marks
3b. Oxygen plasma* for 1 min to `Descum` openings
3c. Etch Si 3 N 4 using SF 6 and F13B1 (1:1) plasma* etch
3d. Etch SiO 2 layer using 6:1 buffered Oxide Etch (BOE)
3e. Rinse in DI then dry in N 2
3f. Etch 3 μm of Si using 1:1 SF 6 :C 2 ClF 5 plasma etch
3g. Clean wafer using standard acid clean (strip resist)**
3h. Strip Si 3 N 4 using concentrated H 3 PO 4 @165° C. for 1 hr
3i. Rinse in DI then dry in N 2
4. Deposit bottom electrodes
4a. Define pattern w/mask #3, positive resist and liftoff process
4b. E-beam evaporate 1000 Å Al using room temp. wafer holder
4c. "Liftoff" excess Al by soaking wafer in hot Acetone
4d. Rinse wafer in fresh Acetone, Methanol, and DI, then dry in N 2
5. Deposit lower oxides
5a. Sputter clean surface, 30 sec
5b. E-beam evaporate 1000 Å SiO 2 substrate is heated to 200° C.
2c. Sputter deposit 2 μm ZnO using Zn target in 5:1 O 2 :Ar gas, 30mTorr. Substrate held to 300° C.
5d. E-beam evaporate 1000 Å SiO 2 substrate is heated to 200° C.
6. Deposit middle electrodes
6a. Define pattern w/mask #4, ppositive resist and liftoff process
6b. E-beam evaporate 1000 Å Al using cold wafer holder
6c. "Liftoff" excess Al by soaking wafer in hot Acetone
6d. Rinse wafer in fresh Acetone, Methanol, and DI, then dry in N 2
7. Deposit upper oxides
7a. Sputter clean surface, 30 sec
7b. E-beam evaporate 1000 Å SiO 2 substrate is held to 200° C.
7c. Sputter deposit 2 μm ZnO using Zn target in 5:1 O 2 ; Ar gas, 30mTorr. Substrate held to 300° C.
7d. E-beam evaporate 1000 Å SiO 2 substrate is held to 200° C.
8. Deposit Top electrodes
8a. Define pattern w/mask #5, positive resist and liftoff process
8b. E-beam evaporate 500 Å Al using room temp. wafer holder
8c. E-beam evaporate 500 Å Au (Gold) using room temp. wafer holder
8d. "Liftoff" excess Al and Au by soaking wafer in hot Acetone
8e. Rinse wafer in fresh Acetone, Methanol, and DI, then dry in N 2
9. Pattern ZnO
9a. Sputter deposit 3000 Å Ti/W using room temp. wafer holder
9b. Define pattern w/mask #6, positive resist
9c. Pattern Ti/W using 30% H 2 O 2 , 30min @ room temp.
9d. Rinse in DI then dry in N 2
9e. Etch top layer SiO 2 using 6:1 BOE (1 min), Rinse in DI
9f. Etch upper ZnO in following solution: 15 g NaNO3, 5 ml HNO3, 600 ml H 2 O, Rinse in DI
9g. Etch middle layer SiO 2 using 6:1 BOE (2 min), Rinse in DI
9h. Etch lower ZnO in following solution: 15 g NaNO3, 5 ml HNO3, 600 ml H 2 O, Rinse in DI
9i. Etch bottom layer SiO 2 using 6:1 BOE (1 min),
9j. Rinse in DI then dry in N 2
9k. Etch 3 μm of Si using 1:1 SF 6 :C 2 ClF 5 plasma etch
9l. Clean wafer, strip resist using Acetone, Methanol, and DI
9m. Strip Ti/W in 30% H 2 O 2 (30 min @ room temp.)
9n. Rinse in DI then dry in N 2
10. Deposit bonding pad metal
10a. Define pattern w/ mask #7, positive resist and liftoff process
10b. E-beam evaporate 1.0μm Al using room temp. wafer holder
10c. "Liftoff" excess Al by soaking wafer in hot Acetone
10d. Rinse wafer in fresh Acetone, Methanol, and DI then dry in N 2
11. Scribe wafers on Side B using saw
12. Deposit Tips
12a. Sputter clean surface for 30 seconds
12b. Place shadow mask on top of wafer, align to pattern using `key` formed with Al/ZnO/Al/ZnO/Au pattern
12c. Deposit 5-10 μm Niobium, forming pointed tips
12d. Carefully remove shadow mask, avoid damaging tips
13. Separate cantilevers from substrate
13a. Deposit 10 μm layer positive resist on Side A
13b. Etch through Si membrane from side B using 3:1 SF 6 :C 2 ClF 5 Plasma* etch
13c. Strip photoresist in Acetone & Methanol, air dry
14. Separate dies (or `chips`) by cracking wafer along scribe lines
*All plasma etches are performed using Power=500 W at 200 mTorr pressure for 6 min, unless otherwise stated
**Standard clean for removing negative photoresist
**a. Agitate vigorously in 120° C. 10:1 H 2 SO 4 :H 2 O 2 for 20 min
**b. Rinse in DI
**c. Soak in 4:1:1 H 2 O:H 2 SO 4 :H 2 O 2 at 90° C. for 20 min
**d. Rinse in DI then dry in N 2
***Standard Pre-Oxidation Clean
***a. Perform above clean (* Standard clean for removing negative photoresist)
***b. Soak in 10:1:1 H 2 O:HCl:H 2 O 2 at 90° C. for 20 min
***c. Rinse in DI
***d. Soak in 10:1:1 H 2 O:NH 4 OH:H 2 O 2 at 90° C. for 20 min
***e. Rinse in DI
***f. Dip in 50:1 BOE for 30 sec at 23° C. (ambient)
***g. Rinse in DI then dry in N 2 .
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There is disclosed herein an integrated scanning tunneling microscope and an integrated piezoelectric transducer and methods for making both. The device consists of one or two arm piezoelectric bimorph cantilevers formed by micromachining using standard integrated circuit processing steps. These cantilevers are attached to the substrate at one area and are free to move under the influence of piezoelectric forces which are caused by the application of appropriate voltages generated by control circuitry and applied to pairs of electrodes formed as an integral part of the bimorph cantilever structure. The electric fields caused by the control voltages cause the piezoelectric bimorphs to move in any desired fashion within ranges determined by the design. The bimorph cantilevers have tips with very sharp points formed thereon which are moved by the action of the control circuit and the piezoelectric bimorphs so to stay within a very small distance of a conducting surface. The movements of the tip can be tracked to yield an image of the surface at atomic resolution
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This is a continuation of Ser. No. 124,506, filed Nov. 23, 1987, now abandoned.
FIELD OF THE INVENTION
The present invention is concerned with a new and improved collapsible luggage cart which has a swingable platform movable from an upright position to a load receiving position, and a handle which is movable from its collapsed position to its upright extended position. The collapsible luggage cart is of the type that may be used for transporting personal luggage or heavy articles to and from an airplane or to and from a boat dock and alike. The present collapsible luggage cart is particularly adapted for being folded into a compact form so that it can be stored in an overhead bin above the passenger seats in an airplane.
The present invention more particularly concerns a new and improved collapsible luggage cart construction having a synthetic plastic or polypropylene latch bar which is pivotly mounted on the luggage carrier and swingable from a storage position to a luggage carrying position. More specifically, the swinging luggage bar has latch means which co-acts with the luggage carrier to secure the luggage carrier in its luggage carrying position when the luggage carrier is dropped from it storage position to a position generally at right angles to the stand. At this point in time, the bar is latched in place to rigidly position the luggage carrier so that it cannot move relative to the stand. Then when it is desired to collapse the luggage carrier and to place its components in their storage position, the latching bar is swingable on its pivot into an upright position generally parallel to the stand with the free end of the latch bar then being latchable to the luggage carrier to immobilize the latch bar and to place it in a storage position. Thereafter an elastic cord is used to secure the luggage carrier and the stand both in upright positions after the luggage carrier has been pivoted at its lower end on the axle from its luggage carrying position to its storage position.
DESCRIPTION OF THE PRIOR ART
Heretofore, various luggage carts have been proposed for use and many of such carts are in common use in many parts of the world today. Examples of such previously known luggage carts are disclosed in the following U.S. Pat. Nos.:
______________________________________Patent No. Patentee______________________________________D-246,774 Patsy Esposito3,540,752 Anuskiewicz3,998,476 Kazmark, Sr.4,037,858 Adams4,072,319 Berger4,284,287 Patsy Esposito4,286,796 Patsy Esposito4,315,635 Patsy Esposito4,431,211 Richard M. Carrigan______________________________________
The state of the art concerning collapsible luggage carts has been discussed in length in U.S. Pat. No., 4,286,796. As for the patents that have been listed above, none of then are believed to be in any way anticipatory of the improved cart or carrier herein disclosed. The patents have been listed above for the purpose of showing the state of the art.
SUMMARY OF THE INVENTION
According to the present invention, a collapsible luggage cart has been provided which includes an axle, wheels mounted thereon, an upright stand mounted on the axle and a luggage carrier pivotably mounted on the cart, the improvement comprising a swingable latch bar swingably mounted at one end on the luggage carrier, latch means secured to the luggage carrier cooperable with the swingable latch bar in either of two separate preselectable positions for locking the luggage carrier in a collapsed upright position for easy transport of the cart and also alternatively for locking the luggage carrier in a luggage carrying position for ready transport of luggage.
According to other features of my invention, I have provided a new and improved swingable latch bar that is comprised of unfilled polypropylene of an injection mold grade.
According to still other features of my invention, I have provided the cart with two horizontally space vertically extending posts in ground engagement and cooperable with the wheels to maintain the cart in a self standing position.
Yet other features of my invention concern a cart having a luggage carrier which includes a U-shaped wire frame and having a cross piece portion at a bight area of the U-shaped wire frame, the cross piece portion having a pair of spaced U-shaped legs for supporting the luggage carrier in ground engagement at its end most distant from its pivot connection with the cart, the legs having notches engageable with the upright posts enabling the luggage carrier to hug the posts on the upright stand in a snug compact nested assembly.
According to further features of my invention I have provided a collapsible luggage cart including an axle, wheels mounted thereon, an upright stand mounted on the axle and a luggage carrier pivotably mounted on the cart and being pivotally movable from an upright storage position to a generally horizontal luggage carrying position, the improvement comprising a swingable latch bar swivelly mounted only at one end on the luggage carrier and selectably movable back and forth from a storage position to a luggage carrier locking position and vice versa so as not to interfere with pivotal folding movement of the luggage carrier, latch means carried on an opposite end of said bar and locking the latch bar in the storage position with said luggage carrier for easy transport of the cart and also alternatively locking the latch bar to said luggage carrier when it is in the generally horizontal luggage carrying position for ready transport to luggage, the latch bar extending along the length of the luggage carrier when in said storage position and extending transversely of the luggage carrier when the luggage carrier is in said luggage carrier locking position.
Still other features of my invention concern a latch bar having hinge means which comprise a synthetic web having a reduced thickness compared to the thickness of the latch bar, the reduced thickness being of the order of 0.013"-0.020" thick.
According to yet further features of my invention I have provided a luggage cart including a pair of spaced wheels mounted on an axle, an upright frame, bracket means mounting the upright frame on the axle, the improvement comprising a luggage platform swingably supported on the axle in operative assembly therewith, the platform being pivotally mounted on the cart and movable from a luggage carrying position to an upright storage position, a synthetic plastic latch bar pivotally mounted at one end on the luggage platform enabling the latch bar to be moved from a horizontal platform latching position to a storage position so as not to interfere with pivotal folding movement of the luggage platform and vice-versa, pivot means between one end of the latch bar and the luggage platform enabling the latch bar to be swung from its horizontal platform latching position to its storage position, latch means adjacent a free end of said latch bar remotely located from said pivot means for latched engagement with the frame when the latch bar is in its horizontal platform latching position for securing the swingable luggage platform in its horizontal luggage receiving position, and a flexible hinge intermediately located between opposite ends of said latch bar enabling the outer free end of the latch bar to be lifted on the flexible hinge out of latched engagement by disengaging said latch means from latched engagement with said platform.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of my luggage cart showing the car in its so-called storage position;
FIG. 2 is a perspective view of the same cart illustrated in FIG. 1 only with the components being partially disassembled;
FIG. 3 is a rear elevation of the cart shown in FIG. 1 only with the cord removed;
FIG. 4 is a horizontal section taken on the line 4--4 looking in the direction indicated by the arrows as seen in FIG. 3;
FIG. 5 is an enlarged perspective view similar to FIG. 2 only as viewed from an opposite corner and showing how the luggage carrier can be moved relative to the stand in the direction indicated by the arrow;
FIG. 6 is a further development of the view shown in FIG. 5 with the arrow showing how the luggage carrier can be moved into ground engagement;
FIG. 7 is an enlarged fragmentary perspective view illustrating how the latch bar can be moved into engagement with the carrier and the stand to lock the components in a luggage carrying position;
FIGS. 8 and 9 are fragmentary rear elevations showing the manner in which the handle can be expanded by exerting forces to the handle structure in the direction indicated by the arrows;
FIG. 10 is an enlarged perspective view showing the cart in its assembled position ready for the receipt of luggage thereon; and
FIG. 11 is an enlarged fragmentary section as viewed on the lines 11--11 in FIG. 10 looking in the direction indicated by the arrows.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The reference numeral 10 indicates generally my collapsible luggage cart. The cart is shown in various positions in the drawings as previously set forth. The cart 10 further includes a horizontal axle 11 which has wheels 12, 12 mounted on wheel bearings 11a which are in the form of synthetic plastic sleeves. These sleeves are positioned at the inside of the wheels 12, 12 and opposite ends of the axle are mounted in the bearings 11a and extend through the wheel hubs 12a as shown in FIGS. 1 and 2. Mounted upon the wheels and the axle is an upright stand indicated generally at 13. Also mounted on the axle 11 is a luggage carrier also indicated generally at 14.
The stand 13 has a stand frame 15 (FIG. 5). This frame 15 includes a pair of lower stand frame legs or posts 16,16 which are secured at opposite ends of the frame legs by welds 17 and 18 to the axle 11 and to the upright stand legs 19 and 20 (FIG. 3).
The welds 17,17 on the frame legs 16,16 are located beneath horizontal strand brace leg 21. The leg 21 extends through aligned sockets 22 (FIG. 3) provided in the stand legs 19 and 20 in assembly therewith. The stand frame 15 further includes U-shaped stand frame member 23 which is mounted in angular inclined relationship to the lower stand frame legs 16,16. The U-shaped stand frame number 23 is comprised of three legs 24, 25 and 26. Opposite ends of frame leg 25 are welded at 27 and 28 to the upright stand legs 19 and 20 (FIG. 3). Now, the free ends of the stand frame legs 24 and 26 are welded at 29 and 30 to the axle 11 to provide a reinforced connection between the stand frame 15 and the axle 11. The welds 27, 28, 29 and 30 (FIG. 3) provide a four point welded connection of the U-shaped stand frame member 23 to the legs 19 and 20 and to the axle 11. (FIGS. 2 and 3).
With this rigidified construction, the stand 13 can be mounted in secured assembly with the axle and the wheels for carrying a substantial load on the luggage carrier 14 of the cart.
The luggage carrier 14 itself is of a heavy wire frame construction and includes a U-shaped main carrier member 30' (FIG. 3) with opposite ends of the U being hook-shaped as indicated at 31 and 32 (FIG. 3). These hook-shaped members 31 and 32 are engaged over the axle 11 and secured in pivoted engagement therewith at 33 (FIG. 2). The hook-shaped members 31 and 32 are adapted to pivot on the axle 11 as the luggage carrier is rotated from its upright position to its horizontal luggage receiving position. The U-shaped main carrier member or wire frame 30' includes a cross piece portion 33' at a bight of the U-shaped wire frame. The cross piece portion 33' has a pair of spaced U-shaped legs 34,34 for supporting the luggage carrier in ground engagement at its end most distant point from its pivotal connection with the cart. These U-shaped legs 34,34 also define leg notches which are engagable with the upright posts to hug the posts 19, 20 (FIG. 1) on the upright stand in snug compact nested assembly when the luggage cart 10 is in its so-called storage position (FIG. 1).
The U-shaped wire luggage carrier member 30' includes parallel luggage carrier legs 31' and 32' and a cross piece leg or portion 33. The cross piece leg or portion 33' joins the parallel luggage carrier legs 31' and 32' together. Mounted on opposite sides of the luggage carrier 14 and joined with the carrier legs 31' and 32' are a pair of wire side reinforcing frames 35 and 36 which are disposed on opposite sides of the luggage carrier for supporting luggage with the expanded width afforded by the frames 35 and 36. As stated before, the entire luggage carrier 14 is carried upon the pair of spaced U-shaped wire legs 34,34 (FIG. 6). These legs are of a sufficient vertical dimension so that when the luggage carrier 14 is in its so-called "down" or luggage receiving position that the platform or luggage carrier will be disposed essentially in a horizontal plane. Positioned at opposite sides of the luggage carrier 14 are a pair of U-shaped wheel guards 37 and 38. These guards not only serve to prevent the luggage from contacting the wheels but also assist in stabilizing the luggage when it is on the cart 10 so that it will be less of a tendency for the luggage to become unsettled or moved off of the carrier 14 as the cart is moved or pulled across the area of use by the operator.
The side frames 35 and 36 are also provided with frame support legs 39--39 (FIG. 6) for reinforcing the side frames and also for assisting in the carrying of a latch bar structure 40 on the luggage carrier 14. The side frames 35 and 36 are joined by springs S to the feet 34,34 on the frame by 33' of the luggage carrier to support outer ends of the side frames.
From a study of the operation of the latch bar structure 40 it will be seen that a pivotly mounted latch bar 41 is provided for locking the luggage carrier 14 in its horizontal luggage carrying position (See FIG. 7).
The latch bar 41 includes a stationary latch bar section 42, a super imposed pivoting latch bar section 43. The super imposed pivoting latch bar section 43 pivots at pivot 44 on the section 42 (FIG. 7). It will be observed that pivot or pivot member 44 has a larger diameter at its top side than it does at its bottom side by comparing the appearance of the pin in FIG. 5 and 6. A lock pin (not shown) can be used to secure the pivot member 44 in assembly with the stationary latch bar section 42. This pin also operates to connect or join the stationary latch bar section 42 with the super imposed pivoting latch bar section 43 in pivoting assembly together. The latch bar 41 also includes a main latch bar section 45 which is joined be a hinge 46 to the pivoting latch bar section 43. The hinge 46 comprises a reduced thickness or area in the latch bar section 43. The hinge 46 operates on an axis which is 90° of the axis of the pivot 44 whereby the latch bar 41 pivots in two planes, either in a horizontal plane or in a vertical plane or at least to a more upright position as is illustrated in FIG. 7. The latch bar has a notched or latched latching portion 47 near an outer free end of the latch bar 41 so that it can be moved into and out of latched engagement with the luggage carrier leg 31' on the luggage carrier 14 (FIG. 7).
Now from a review of FIG. 10, it will be seen that when the latch bar 41 is in its secured position it has a pair of arcuate C-shaped notched areas 50,50 movable into and out of nested engagement with the stand legs or posts 19 and 20 enabling the luggage carrier to hug the posts on the upright stand in snug compact nested assembly. It will be further observed that the notched areas 50,50 have an upstanding arcuately shaped flange 50a to increase the area of engagement between the C-shaped notched area and the legs for stabilizing the manner of the engagement of the latch bar 41 with the upright posts 19 and 20. The upstanding flange 50a of the C-shaped notched areas 50,50 are formed integral of the same synthetic plastic as the latch bar 41.
Now the pivotly mounted latch bar 41 also has an enlarged plastic area (FIG. 10) providing an integral downwardly extending latch bar flange 51 (FIG. 11). Disposed adjacent to the latch bar flange is a reinforcing latch bar rib 52 (FIG. 11). Provided in an outer end of the latch bar 41 and more particularly in the latch bar 51 is a latch bar retainer notch or notched generally arcuately shaped edge 53. Adjacent to the notch or arcuate edge 53 are lead in flanges 54,54 which enable the operator to more readily center and engage the luggage carrier leg 31 therein. It will thus be observed that the notch or arcuate edge 53 serves to provide a horizontal locked position for the latch bar 57 for locking the luggage carrier in its luggage carrying position for ready transport of luggage.
Now referring to FIGS. 3 and 4 it will be further observed that the latch bar 41 has a series of longitudinally extending reinforcing ribs 55 (FIG. 4). The latch bar further 41 is further formed so as to have a cut out area 56 for enabling frame portions of the luggage carrier 14 to be snugly engaged in the cut out area 56 in assembly with the latch bar 41 when the latch bar is in its upright locked or stored position as seen in FIG. 3. In order to lock the luggage bar 41 in its upright position, the latch bar is further provided with a notched area 56. Lead in converging edges or flanges 54,54 are disposed in adjacency to the notched area 56 to assist in allowing a leg of one of the reinforcing wire side frames to be retainingly engaged in the retainer notch 53 (FIG. 4). This locking action between the latch bar 41 and the side frame of the luggage carrier 14 permits the swingable latch bar 41 to be locked in its upright stored position for easy transport of the cart when the luggage carrier 14 is in its "stored" position. In order to further maintain the components of the cart 10 in a collapsed or stored position, the cart is provided with an elastic strap 57 having hooks 58 at opposite ends. Straps of this type of well-known in the art. More specifically, the strap 57 is shown in FIG. 1 and this Figure illustrates how the strap serves to maintain the luggage carrier 14 in an upright collapsed or stored position on the stand 15. In order to release the stand and the luggage carrier, the cord 57 must be removed by disengaging the hooks 58. After the elastic cord 57 is removed, then the force of gravity acting on the luggage carrier 14 moves the luggage carrier 14 to a relaxed position as shown in FIG. 2.
Now in order to facilitate the transport of the cart 10 by the user, either before or after luggage bags are placed on the luggage carrier 14, the cart 10 is provided with an expanding handle construction as indicated generally at 60 in FIG. 8 and 9. To this end, the expanding handle construction 60 includes a series of telescoping superimposed handle sections 61,66 and push button 62,62. The push buttons are spring actuated so that they normally are in an extended spring urged position but when depressed allow the superimposed sections 66--66 to slide over the push buttons 62,62 so that the handle 60 can either be expanded or contracted as required. The intermediate section 63 also includes a pair of upright posts 64,64. Disposed above the intermediate section 63 are the sections 61,11. The uppermost handle section 66 which includes a pair of handle legs 67,67 and a handle 68. From a consideration of FIGS. 8 and 9, it will thus be understood how the handle can be expanded and/or contracted either into an operating position or into a storage position as desired.
In the normal operation of my cart, the user can commence use of the cart by removing the elastic cord 57 as previously described. With the removal of the cord, the gravity action force on the luggage carrier causes the luggage carrier 14 to move to the position shown in FIG. 2. At this point, the user can then apply a force to the luggage carrier 14 as indicated by the arrow 70 in FIG. 5 to cause the luggage carrier 14 to move into ground engagement so that its feet 34,34 are in ground engagement as seen in FIG. 6. The arrow 70 in FIG. 6 also shows the further pivoting movement of the luggage carrier 14 from its FIG. 5 to its FIG. 6 position as the carrier 34 pivots at the point where the hook-shaped members 31 and 32 are engaged with the axle 11. Now that the luggage carrier 14 has been moved to its luggage carrying position, the latching bar 41 can then move on its pivot 44 into its horizontal latched position. When in its horizontal latched position, the notched area 53 (FIG. 11) can be forceably urged into engagement with the carrier leg as shown in FIGS. 10 and 11.
After the user has used the cart and has removed the cord 57 from the luggage secured to the cart, the cart can be collapsed. The collapsing of the cart can be brought about by lifting the outer end of the luggage bar 41 by applying a force in an opposite direction to the arrow indicated at 71 in FIG. 10. The arrow 71 serves to show how the outer end of the latch bar 41 can be pushed to engage the notched area 53 with the leg of the luggage carrier 14. After the luggage bar 41 has been disengaged, it can be rotated 90° on pivot 44 into parallelism with the legs of the luggage carrier. At this point in time, a force can again be applied to the outer end of the latch bar structure 40 as generally indicated at 70 in FIG. 6 to cause the luggage cart and the outer end of the latch bar 41 to be secured to maintain the latch bar in a secured upright position as shown in FIG. 3.
It is thus seen, therefore, that there is provided an improved article in which the objects of the invention are achieved and which are well adapted to meet all conditions of practical use.
As various possible embodiments may be made in the above invention for use for different purposes and as various changes might be made in the embodiments and method above set forth, it is understood that all of the above matters here set forth or shown in the accompanying drawings are to be interpreted as illustrative and not in a limiting sense.
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A luggage cart including a pair of spaced wheels mounted on an axle. An upright frame and bracket means mounting the upright frame on the axle. The improvement comprising a luggage platform swingably supported on the axle in operative assembly therewith. A synthetic plastic latch bar pivotally mounted at one end on the luggage platform enabling the latch bar to be moved from a horizontal position to an upright position and vice-versa. A pivot structure between one end of the latch bar and the luggage platform enabling the latch bar to be swung from its horizontal platform latching position to its upright inoperative storage position. A latch structure adjacent a free end of the latch bar remotely located from the pivot structure for latched engagement with the frame when the latch bar is in its horizontal position for securing the swingable luggage platform in its horizontal luggage receiving position. A flexible hinge intermediately located between opposite ends of the latch bar enabling the outer free end of the latch bar to be lifted on the flexible hinge out of latched engagement by disengaging the latch structure from latched engagement with the platform.
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FIELD OF THE INVENTION
The present invention relates generally to an oscillation circuit, and more particularly, to an oscillation circuit using a band-pass filter.
BACKGROUND OF THE INVENTION
Conventionally, oscillation circuits typically utilize an LC oscillator comprised of an inductor and a capacitor producing an inductance L and a capacitance C, respectively. The LC oscillator has a good stability and a relatively good S/N (signal to noise) ratio. However, the LC oscillator generally is unsuitable for an oscillation circuit intended to be fabricated on an IC (integrated circuit). This is because inductors are difficult to form on ICs.
Recently, new oscillation circuits, which are suitable for fabrication in ICs, were invented by one of the same inventors. The prior invention is now pending as Japanese Patent Application No. 61-172244 which was filed on July 22, 1986, and was filed in the U.S. on July 15, 1987 and assigned Ser. No. 07/074,294. The oscillation circuit according to the prior invention has been constructed by using band-pass filters. FIG. 1 shows an example of such a oscillation circuit using band-pass filters.
Referring now to FIG. 1, the oscillation circuit using band-pass filters according to the prior invention will be described. In FIG. 1, the oscillation circuit is comprised of a band-pass filter 10 and a limiter amplifier 12. An output terminal 10a of the band-pass filter 10 is coupled to its input terminal 10b through the limiter amplifier 12. Thus, the oscillation circuit forms a loop circuit consisting of the band-pass filter 10 and the limiter amplifier 12.
The band-pass filter 10 includes a pair of integration circuits 14 and 16. Each of the integration circuits 14 and 16 includes a voltage to current conversion circuit (referred as V/C converter hereafter) 18 and 20 respectively and a capacitor 22 and 24 respectively. Thus, each of the integration circuits 14 and 16 has a prescribed time constant defined by the conductance of the V/C converter and the capacitance of the capacitor. The V/C converters 18, 20 are constructed in a differential amplifier configuration.
The non-inverted input terminal 18a of the first V/C converter 18 is coupled to a DC voltage source 26 with a prescribed DC voltage. The output terminal 18b of the first V/C converter 18 is coupled to one end of the first capacitor 22 and the noninverted input terminal 20a of the second V/C converter 20. The output terminal 20b of the second V/C converter 20 is coupled to one end of the second capacitor 24 and the inverted input terminals 18c and 20c of the first and second V/C converters 18 and 20.
The inverted input terminal 18c of the first V/C converter 18 is directly coupled to the output terminal 20b of the second V/C converter 20. While the inverted input terminal 20c of the second V/C converter 20 is coupled to the output terminal 20b of the second V/C converter 20 through a voltage divider 28.
The output terminal 20b of the second V/C converter 20 is also coupled to the input terminal 12a of the limiter amplifier 12 through the output terminal 10a of the band-pass filter 10. The output terminal 12b of the limiter amplifier 12 is coupled to the other end of the first capacitor 22 through the input terminal 10b of the band-pass filter 10. By the way, the other end of the second capacitor 24 is grounded.
In the oscillation circuit, the output Va of the band-pass filter 10 on the output terminal 10a is fed back to the input terminal 10b through the limiter amplifier 12 in a positive phase relation. The transfer characteristics Tf of the band-pass filter 10 is expressed by the following equation: ##EQU1## where, gm18 is the conductance of the first V/C converter 18;
gm20 is the conductance of the second V/C converter 20;
m is the voltage dividing ratio of the voltage divider 28 (m<1);
C22 is the capacitance of the first capacitor 22; and
C24 is the capacitance of the second capacitor 24. Now, assuming that: ##EQU2## where ω represents an angular frequency, the Equation (1) is expressed as follows: ##EQU3##
When it is assumed that ω1=ω2=ω0, the Equation (3) becomes as follows: ##EQU4##
The transfer characteristic Tf of the band-pass filter 10, given by the Equation (4), has the frequency characteristics shown in FIG. 2, in which the graphs 2(A) and 2(B) show the frequency characteristics in regard to an absolute level La and a phase angle Ap of the transfer characteristics Tf.
When the output Va of the band-pass filter 10 having these characteristics is fed back to the input terminal 10b of the band-pass filter 10 in the positive phase relation through the limiter amplifier 12, oscillation takes place at the angular frequency ω0 as a resonance angular frequency. The resonance angular frequency ω0 varies in accordance with the conductances gm18 and gm20. Thus, the oscillation circuit can be operated as a voltage controlled oscillator by controlling the conductances gm18 and gm20.
In the oscillation circuit, as shown in FIG. 1, the input Vb fed back through the limiter amplifier 12 has been given by the voltage configuration. The limiter amplifier 12 generally includes an emitter follower type buffer (not shown) for supplying the input Vb of the voltage configuration. As is well known, emitter follower type buffers need a relatively large amount of current to operate. However, it is difficult to flow large currents in ICs, because ICs have become too large in scale for flowing a relatively large current.
If the emitter follower type buffer in the limiter amplifier 12 is driven by a relatively small current, the limiter amplifier 12 fails to supply the band-pass filter 10 with the input Vb in a stable state. Thus, the oscillation signal obtained by the oscillation circuit can be distorted. Further, an insufficient current for the emitter follower type buffer of the limiter amplifier 12 causes a phase delay in the oscillation signal. The phase delay may cause a shift of the oscillation frequency from a desired resonance frequency, i.e., the prescribed angular frequency ω0.
To avoid this problem, a push-pull type buffer may be considered for use in the band-pass filter 10 in place of the emitter follower type buffer. However, in this configuration the limiter amplifiers becomes more complicated occurs and more space is needed in the IC.
As described above in detail, in the oscillation circuit using band-pass filters according to the prior onvention, the oscillation frequency may shift from a desired resonance frequency if the band-pass filter is driven by a small current. On the other hand, a limiter amplifier for driving the band-pass filter becomes too large in scale and complicated in structure when a push-pull type buffer is used in the limiter amplifier for driving the band-pass filter.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an oscillation circuit which is more suitable for fabrication in ICs, and which does not occupy an inordinate space.
Another object of the present invention is to provide an oscillation circuit which is simple in structure and capable of driving a band-pass filter satisfactorily without causing an undesired shift of the oscillation frequency from a prescribed resonance frequency.
In order to attain the above objects, the present invention converts the output of the band-pass filter into current signal and feeds it back to the band-pass filter.
In the circuit construction, the band-pass filter is driven by current, and shifts of the oscillation frequency caused by a phase delay resulting from distortion of the signal can be reduced while avoiding undesired complication of the circuits.
Additional objects and advantages of the present invention will be apparent to persons skilled in the art from a study of the following description and the accompanying drawings, which are hereby incorporated in and constitute a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a circuit diagram which shows the structure of an oscillation circuit according to a prior invention;
FIG. 2 is a graph diagrams which shows the characteristics of the band-pass filter shown in FIG. 1;
FIG. 3 is a circuit diagram which shows the structure of one embodiment of the present invention;
FIG. 4 is a partial equivalent circuit of the circuit shown in FIG. 3; and
FIG. 5 is a circuit diagram which shows the detailed structure of the embodiment of the circuit shown in FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail with reference to the FIGS. 3 through 5. Throughout the drawings, reference numerals or letters used in FIG. 1 will be used to designate like or equivalent elements for simplicity of explanation.
Referring now to FIG. 3, a first embodiment of the oscillation circuit using band-pass filters according to the present invention will be described in detail. In FIG. 3, the first embodiment of the oscillation circuit is comprised of a band-pass filter 10 and a V/C converter type limiter amplifier 30. An output terminal 10a of the band-pass filter 10 is coupled to its input terminal 10b through the V/C converter type limiter amplifier 30. Thus, the oscillation circuit forms a loop circuit consisting of the band-pass filter 10 and the V/C converter type limiter amplifier 30.
The band-pass filter 10 includes a pair of integration circuits 14 and 16. Each of the integration circuits 14, 16 includes a V/C converter 18, 20 and a capacitor 22, 24. Thus, each of the integration circuits 14, 16 has a prescribed time constant defined by the conductance of the V/C converter 18, 20 and the capacitance of the capacitor 22, 24. The V/C converters 18, 20 are constructed in a differential amplifier configuration.
The non-inverted input terminal 18a of the first V/C converter 18 is coupled to a DC voltage source 26 with a prescribed DC voltage. The output terminal 18b of the first V/C converter 18 is coupled to one end of the first capacitor 22 and the non-inverted input terminal 20a of the second V/C converter 20. The output terminal 20b of the second V/C converter 20 is coupled to one end of the second capacitor 24, the other end of which is grounded, and the inverted input terminals 18c and 20c of the first and second V/C converters 18 and 20.
The inverted input terminal 18c of the first V/C converter 18 is directly coupled to the output terminal 20b of the second V/C converter 20. While the inverted input terminal 20c of the second V/C converter 20 is coupled to the output terminal 20b of the second V/C converter 20 through a voltage divider 28.
The output terminal 20b of the second V/C converter 20 is also coupled to the input terminal 30a of the V/C converter type limiter amplifier 30 through the output terminal 10a of the band-pass filter 10. The output terminal 30b of the V/C converter type limiter amplifier 30 is coupled to the other end of the first capacitor 22 through the input terminal 10b of the band-pass filter 10.
The V/C converter type limiter amplifier 30 is comprised of a resistor 32 and a variable current source 34. The resistor 32 and the variable current source 34 are connected in parallel with each other and connected between the first capacitor 22 and a reference terminal such as a ground terminal.
The variable current source 34 is coupled to the output terminal 10a of the band-pass filter 10 so that the current I 34 of the variable current source 34 is controlled in response to an output Va of the band-pass filter 10. Thus, the variable current source 34 converts the voltage configuration output Va of the band-pass filter 10 into a current configuration input I34 and feeds it to the input terminal 10b of the band-pass filter 10. Then, a voltage configuration input Vb on the input terminal 10b is expressed by the following equation:
Vb=R32·I34 (5)
where R32 is the resistance of the resistor 34.
The V/C converter type limiter amplifier 30 is equivalent to the circuit shown in FIG. 4. Therefore, the transfer characteristic Tf of the band-pass filter 10 is expressed by the following equation: ##EQU5## where, gm18 is the conductance of the first V/C converter 18;
gm20 is the conductance of the second V/C converter 20;
m is the voltage dividing ratio of the voltage divider 28 (m<1);
C22 is the capacitance of the first capacitor 22; and
C24 is the capacitance of the second capacitor 24. Now, assuming that: ##EQU6## the Equation (6) is expressed as follows: ##EQU7##
When it is assumed that ω1=ω2=ω0, the Equation (8) becomes as follows: ##EQU8##
The transfer characteristics Tf of the band-pass filter 10, given by the Equation (9), has also the frequency characteristics, as shown in FIG. 2.
When the output Va of the band-pass filter 10 having these characteristics is fed back to the input terminal 10b of the band-pass filter 10 in the positive phase relation through the V/C converter type limiter amplifier 30, oscillation takes place at the angular frequency ω0 as a resonance angular frequency. In the resonance angular frequency ω0, a following relation is given:
S=j·ω0 (10)
Thus, the Equation (9) becomes as follows: ##EQU9##
Now, assuming the voltage dividing ratio m=0, a following relation is established: ##EQU10##
The condition of the voltage dividing ratio m=0 can be realized by coupling the inverted input terminal 20c of the second V/C converter 20 to any reference potential source.
When substituting the input Vb of the Equation (5), the Equation (12) is expressed as follows: ##EQU11##
As is understood from the Equation (13), the output Va of the band-pass filter 10, i.e., the oscillation output of the oscillation circuit according to the first embodiment becomes independent from the resistance R 32 of the resistor 32. Furthermore, there is no possibility for causing distortion because of current driving.
FIG. 5 is a circuit diagram showing a practical example of the oscillation circuit according to the present invention. The circuit shown in FIG. 5 is applied to a voltage controlled oscillator. In FIG. 5, the voltage controlled oscillator is comprised of three differential amplifiers 100, 200 and 300 and a pair of capacitors 22 and 24. First and second differential amplifiers 100, 200 correspond to the first and second V/C converters 18, 20 of the first embodiment. Third differential amplifier 300 corresponds to the V/C converter type limiter amplifier 30 of the first embodiment.
The first and second differential amplifiers 100, 200 are especially constructed in a Gilbert circuit configuration. The basic construction of Gilbert circuit type differential amplifiers is described in detail, for instance, in the U.S. Pat. Nos. 3,931,583, 4,075,574 and 4,156,283.
In the first differential amplifier 100, a pair of first and second transistors 101 and 102 are coupled to each other in a differential amplifier configuration. The collector of the first differential transistor 101 is directly coupled to a power supply terminal Vcc. The collector of the second differential transistor 102 is coupled to the power supply terminal Vcc through a transistor 103 forming an active load for the first differential amplifier 100. Their emitters are connected in common to each other and coupled to a ground terminal E through a first current source 104. The first current source 104 includes a transistor 105 and an emitter resistor 106 connected in series.
The base of the first differential transistor 101 is coupled to a DC voltage source 26 through a resistor 107 and a transistor 108. The base of the second differential transistor 102 is coupled to the third differential amplifier 300 through a resistor 109, as described later. The bases of the transistors 101, 102 are further coupled to to the ground terminal E through diodes 110 and 111, respectively, and a second current source 112, in common. The second current source 112 includes a transistor 113 and an emitter resistor 114 connected in series. The collector of the second transistor 102 is connected to a capacitor 22, as described later.
In the second differential amplifier 200, a pair of third and fourth transistors 201 and 202 are coupled to each other in a differential amplifier configuration. The collector of the third differential transistor 201 is directly coupled to a power supply terminal Vcc. The collector of the fourth differential transistor 202 is coupled to the power supply terminal Vcc through a transistor 203 forming an active load for the second differential amplifier 200. Their emitters are connected in common to each other and coupled to the ground terminal E through a third current source 204. The third current source 204 includes a transistor 205 and an emitter resistor 206 connected in series.
The base of the third differential transistor 201 is coupled to the collector of the second differential transistor 102 in the first differential amplifier 100 through a resistor 207 and a transistor 208. The base of the fourth differential transistor 202 is coupled to the DC voltage source 26 through a resistor 209 and a transistor 210. The bases of the transistors 201, 202 are further coupled to to the ground terminal E through diodes 211 and 212, respectively, and a fourth current source 213, in common. The second current source 213 includes a transistor 214 and an emitter resistor 215 connected in series. The collector of the fourth differential transistor 202 is connected to the power supply terminal Vcc through a second capacitor 24.
In the third differential amplifier 300, a pair of fifth and sixth transistors 301 and 302 are coupled to each other in a differential amplifier configuration. The collector of the fifth differential transistor 301 is directly coupled to the power supply terminal Vcc. The collector of the sixth differential transistor 302 is coupled to the power supply terminal Vcc through a resistor 32, as described later. Their emitters are connected in common to each other and coupled to a ground terminal E through a fifth current source 303. The fifth current source 303 includes a transistor 304 and an emitter resistor 305 connected in series.
The base of the fifth differential transistor 301 is coupled to the collector of the fourth differential transistor 202 in the second differential amplifier 200 through a transistor 306. The base of the sixth differential transistor 302 is coupled to another DC voltage source 401. The collector of the sixth differential transistor 202 is connected to the first differential amplifier 100 through the first capacitor 22.
The bases of the active load transistors 103 and 203 are coupled to the base of a transistor 402. The collector of the transistor 402 is connected to its base so that the transistor 402 operations as a diode. The transistor 402 is coupled between the power supply terminal Vcc and the ground terminal E through a sixth current source 403. Thus, the transistors 103, 203 and 402 forms a first current mirror circuit. The sixth current source 403 includes a transistor 404 and an emitter resistor 405 connected in series.
The bases of the transistors 105, 205, 304 and 404 in the first, third, fifth and sixth current sources 104, 204, 303 and 403 are coupled to the base of a transistor 406. The collector of the transistor 406 is connected to its base so that the transistor 406 functions as a diode. The collector and emitter of the transistor 406 are coupled to the power supply terminal Vcc and the ground terminal E through a variable resistor 407 and an emitter resistor 408. Thus, the transistors 105, 205, 304, 404 and 406 forms a second current mirror circuit.
The bases of the transistors 113 and 214 in the second and fourth current sources 112 and 213 are coupled to the base of a transistor 409. The collector of the transistor 409 is connected to its base so that the transistor 409 functions as a diode. The collector and emitter of the transistor 409 are coupled to the power supply terminal Vcc and the ground terminal E through a resistor 410 and an emitter resistor 411. Thus, the transistors 113, 214 and 409 forms a third current mirror circuit.
Here the following is assumed. That is, the resistances R107, R109, R207 and R209 of the resistors 107, 109, 207 and 209 have the same value Re. The currents I104 and I204 of the first and third current sources 104 and 204 have the same value Ix. And the currents I112 and I213 of the second and fourth current sources 112 and 213 have the same value Is. Then, the conductances gm100 and gm200 of the first and second differential amplifiers 100 and 200 are expressed as follow: ##EQU12##
Here, it is assumed that the conductances gm100 and gm200 are equal to conductances gm18 and gm20, respectively.
According to the Equation (14), the conductances gm100 and gm200 can be varied by controlling the current Ix of the current sources 105, 205. The current Ix is controlled by adjusting the variable resistor 407. The oscillation frequency of the circuit varies in accordance with the conductances gm100 and gm200. As a result, the circuit, shown in FIG. 5, operates as a voltage controlled oscillator.
A voltage configuration output Va of the voltage controlled oscillator is obtained from the emitter of the transistor 306. The feed back current Ib is equal to the difference between the collector current of transistor 302 and the current flowing through the resistor 32. The output Va is applied to the base of the fifth differential transistor 301 of the third differential amplifier 300.
The third differential amplifier 300 outputs a current from the collector of the sixth differential transistor 302, in response to the output Va. The current is fed back to the first differential amplifier 100 through the first capacitor 22, as a current configuration input Ib of the voltage controlled oscillator.
Thus, the input Ib and the output Va are expressed as follows: ##EQU13## where k is constant.
In the voltage controlled oscillator of FIG. 5, the resistance Re of the resistors 107, 109, 207 and 209, the constant k and the current Is of the current sources 112 and 213 are set in constant. Therefore, the levels of the input Ib and the output Vb, as expressed by the Equations (15), (16), become constant. Accordingly, the voltage controlled oscillator can provide a stable oscillation output, regardless of the resistance of the resistor 32 and the current Ix of the current sources 105, 205.
As described above, the present invention can provide an oscillation circuit which is simple in construction and is capable of driving a band-pass filter satisfactorily without causing a shift of the oscillation frequency.
While there has been illustrated and described what are at present considered to be preferred embodiments of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made, and equivalents may be substituted for elements thereof without departing from the true scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teaching of the present invention without departing from the central scope thereof. Therefore, it is intended that this invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention include all embodiments falling within the scope of the appended claims.
The foregoing description and the drawings are regarded by the applicant as including a variety of individually inventive concepts, some of which may lie partially or wholly outside the scope of some or all of the following claims. The fact that the applicant has chosen at the time of filing of the present application to restrict the claimed scope of protection in accordance with the following claims is not to be taken as a disclaimer of alternative inventive concepts that are included in the contents of the application and could be defined by claims differing in scope from the following claims, which different claims may be adopted subsequently during prosecution, for example for the purposes of a dividual application.
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An oscillation circuit for an integrated circuit device. The oscillation circuit includes a band-pass filter for producing an output signal having a voltage and a defined resonance frequency and a voltage to current converter type limiter amplifier connected to the band-pass filter for supplying a current to the band-pass filter corresponding to the voltage of the output signal of the band-pass filter.
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[0001] This application claims the benefit of U.S. Ser. No. 60/555,150 filed Mar. 22, 2004, the disclosure of which is hereby incorporated by reference.
BACKGROUND
[0002] Excessive interstitial fluid accumulation, referred to as edema, may arise from a variety of illnesses and conditions, including venous valvular insufficiency, postphlebotic syndrome, and lymphedema. Control of this edema by reduction of interstitial fluids is important to increase PO2 delivery to tissues, relieve pain from swelling, and decrease risk of infection. Decreasing drainage of fluid from sores, skin breaks, and/or ulcerations promotes wound closure, prevents wound breakdown, and decreases risk of blood clot formation in veins.
[0003] Thus, it is desirable to have a customizable or off-the-shelf compressive device that can be readily available for application to a body part to prevent excessive fluid accumulation resulting from a variety of diseases and maladies.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is an illustration of one embodiment of a modular compression garment according to the present disclosure.
[0005] FIG. 2 is a perspective view of a band used in the modular compression garment of FIG. 1 .
[0006] FIG. 3 is a break-away view of the compression garment of FIG. 1 including one embodiment of a spine used for connecting a plurality of bands such as those shown in FIG. 2 .
[0007] FIGS. 4 and 5 are alternative embodiments of a modular compression garments of the present invention.
[0008] FIG. 6 is a side perspective view of a footpiece for use with a modular compression garment.
[0009] FIG. 7 is a side view of a liner for use with a modular compression garment.
[0010] FIG. 8 is an illustration of an order form for ordering a customized compression garment.
DETAILED DESCRIPTION
[0011] The present disclosure relates generally to treatment of edema and, more specifically, to a device for applying compressive pressure to a person's body in order to facilitate reduction of interstitial fluids from a body trunk and/or limb extremity and to provide support and fatigue relief.
[0012] It is to be understood that the present disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not, in itself, dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.
[0013] FIG. 1 illustrates one embodiment of the present disclosure applied as a lower limb compression garment 100 . In this embodiment, the lower limb compression garment 100 includes several bands 102 that are of adjustable size by way of attachment mechanisms 104 for conforming, in the present embodiment, to a human leg 106 . The lower limb compression garment 100 also includes an anklet 108 for conforming to a human ankle.
[0014] It is understood that the present invention is not limited to use with the leg, but can be used in various limbs and trunks of humans. It is further understood the invention is not limited to humans, but may apply for veterinarian use such as for a horse, dog, or other animal. For example, another embodiment may be used to compress an entire leg or arm of a human or a leg of a horse or dog. Various embodiments of the present disclosure may also provide for maximal access to a portion of a limb. These embodiments may have the compression band 102 over the affected area on top, with the proximal and distal compression bands underlapping. This may allow removal of a compression band or bands 102 over the affected area, while not requiring removal of the entire garment. Thus, the rest of the garment 100 may remain therapeutic while the area is accessed.
[0000] The Bands 102 and Attachment Mechanisms 104
[0015] Referring also to FIG. 2 , the bands 102 may include an inner layer 114 and an outer layer 112 with optional elastomeric compression material layer 110 . In one embodiment an elastomeric loop material 112 such as Shelby Elastics Mon-3 or WonderWrap (Shelby, N.C.) may be sewn onto a backing of elastomeric fabric 114 such as Schoeller® Prestige 58012 (Sevelen, Switzerland). The elastomeric fabric 114 may be sewn on-the-bias so as to provide more stretch. For higher compression for a given amount of stretch, the fabric 114 may be sewn not-on-the-bias. Therefore sewing a highly elastic loop fabric 114 onto the backing of the material 110 may alternate percentage stretchability and alternate the compression gradient, based upon material selection and if it is sewn on-the-bias or not on-the-bias. Sewing such elastomeric fibers 114 on-the-bias may allow more stretch but less compression. For example, sewing the WonderWrap on the Schoeller fiber on-the-bias may result in a 20-30% elastomeric range with good compression. Sewing the WonderWrap on the Schoeller fiber not on-the-bias may result in a 15-20% elastomeric range with more compression. This way several embodiments can be easily engineered to provide different common classes of compression such as 8-15 mm, 15-20 mm, 20-30 mm, 30-40 mm, or 40+mm. This may allow the garment 100 to be applied lightly or tighter and more therapeutic. If applied past the range of the therapeutic stretch, then the compression applied may be directly proportional to that the user applies.
[0016] In other embodiments, a thin semi-compressible layer 110 is provided between an inner layer 114 and the outer layer 112 of the bands 102 . This layer 110 may be made of polyurethane foam such as Rosidal Soft (Lohmann Rauscher Neuwied, Germany). Such foam would ideally by 0.3 cm thick, although other ranges of thickness 0.05 cm to 5 cm are possible. The layer 110 may include particles made of compressible, high resiliency, low density, open cell plastic foam. Such particles ground up and of different particle sizes and shaped particles can create areas of high pressure areas and intersecting networks of low pressure areas at the seams. Use of such particles for compression garments is known in the art and sold as the Tribute™ (Solaris Inc. Brookfield, Wis.). Other materials for the compressible layer 110 may include rubber, plastic air bubbles, foam air bubbles, or non-convolute foam. The semi-compressible layer 110 may have channels sewn in them to create lines of natural lymph flow or criss-cross pattern. Alternatively, in other embodiments the foam may serve as the inner layer with a loop-compatible fabric or elastomeric material as the outer layer.
[0017] In still other embodiments, the bands 102 may not be multi-layered, as described above, but consist essentially of elastomeric yarns, for example, PowerNet™ nylon or nylon/spandex, ComfortWeave™ polyester/spandex, Clearspan® spandex manufactured by Radici, Dorlastain® spandex manufactured by Bayer, Lycra® spandex manufactured by DuPont, and any other spandex yarn, or special woven cotton fabrics such as Comprilan® short-stretch bandage, manufactured by Beiersdorf AG. Another elastomeric compression material that may be used is Lovetex® Industrial Corporation Breathe Freely (Taipei, Taiwan). It is understood in the spirit of the disclosure that any suitable elastic material may be used and is not limited to those listed above. In the present example, the chosen material would be in a range of 15% to 100% elastic stretch, although other ranges are anticipated.
[0018] In still other embodiments, the band 102 may include the elastomeric semi-compressible layer and a thin outer layer of Velcro® (hook and loop) compatible fabric. Such a garment may be sold as a reusable, semi-disposable, or disposable garment. For example, as single-use embodiment might be sold sterile and for application directly after surgery on an affected limb in order to control swelling and prevent wound dehiscence, or to allow selective access postoperatively to access directly over incision or wound, while leaving rest of garment in tact. Other single-uses may include general hospital use or as outpatient clinic or home use in order to reduce or control interstitial edema. Alternative uses may be to hold a bandage or medication against a limb member.
[0019] The attachment mechanisms 104 , which is connected to or connectable to the bands 102 , allow the bands to interconnect to one another. The attachment mechanisms 104 can be of various types such as hooks, snaps, buttons, and glue/adhesive, and some mechanisms for some bands 102 may be different than those for other bands on the same garment 100 . In the example of FIG. 2 , the attachment mechanisms include a hook-and-loop fastener, such as a Velcro® strip. Each band 102 may fasten to itself in such a way as the user can apply the band under compression and it will hold the compression against the body part. The hook of the hook-and-loop fastener may be sewn onto one end of the band and the body of the band or a portion thereon may have the loop material.
[0020] In this embodiment, some or all of the exterior surfaces 112 of the bands 102 may include elastomeric loop material. The material therefore may interlock with the hook material of the attachment mechanisms 104 and/or a spine (discussed below). The use of loop material along the outside layer 112 of the band 102 allows each band to apply to a wider range of compression. Also, the use of elastomeric loop material may allow the dual function of attachment to the other end of the band, which has hook material, as well providing active compression.
[0021] In varying embodiments, the bands 102 interconnect to each other in a temporary, semi-permanent, or permanent manner. The connections may use chemical, thermal, or mechanical bonds. Mechanical temporary and semi-permanent bonds may include hook and loop, snaps, button and button-holes, or ties and eyelets. Mechanically bonded permanent attachments may include methods such as sewing and stapling. Chemical bonding includes methods such as fabric glue and super glue. Such glue is well-known in the art and used extensively in the industry for upholstery, furniture, and other products. Other forms of chemical bonding include tape adhesive such as PEELnSTICK and the acid-free acrylic double-sided adhesive SuperTape (Therm O Web, Wheeling II). Thermal bonding may include iron-on interfacing, ultrasonic welding of compatible components, or thermal melting of compatible components or iron-on interfacing. Such iron-on interfacing may for example include one or more layers of HEATNBOND® Ultrahold (Them O Web, Wheeling II). Some of the bonds (e.g., hook and loop) allow the garment 100 to be reused many times. Other bonds (e.g., fabric glue) may allow the garment 100 to be reused only a certain number of times. For example, the fabric glue may be reusable for a period of days, but afterwards may loose its adhesion properties. Still other bonds (e.g., thermal welding) are for a single use.
[0022] For example, a lower perimeter 114 a (towards the foot in the present embodiment) of the interior layer 114 may include a relatively soft hook material. The soft hook material 114 a may overlap on the band 102 immediately below, thus interlocking between the adjacent bands and providing additional stability of the device. Alternatively, an upper perimeter 112 a (away from the foot in the present embodiment) of the outer layer 112 may include hook material. The lowest band may attach to loop material sewn onto the anklet 108 or attach to the elastomeric loop band at the top of the footpiece. In some embodiments, there will be no soft hook material at the facing edges of the bands and the bands will simply overlap each other with the lowest band overlapping an anklet or footpiece.
[0023] Small geographic symbols may be drawn or printed on each band 102 which will change shape in a characteristic way when the proper compression is applied so that the user knows the prescribed therapeutic compression is being applied. Such symbols are well known in the art, and are applied currently to short-stretch bandages such as sold by SSL International PLC under the trade name of Setopress (London, England). In another embodiment, material color or material markings will differentiate different bands of varying levels of compression.
[0000] The Spine 120
[0024] Referring now to FIG. 3 , in one embodiment, the bands 102 are joined together at a spine 120 . The bands 102 can be joined to the spine 120 in various manners, and in the present embodiment they are sewn together. The spine 120 may comprise non-elastic or elastic material. There may be no difference in bulk or therapeutic application of this embodiment. Furthermore, the bands 102 may be partially or completely sewn together. In this embodiment, the bands 102 and spine 120 may be separately pre-manufactured, and then sewn together once measurements are made of the affected limb. By modifying the degree of overlap of the bands and the number of bands, a wide geometry of limbs may be fitted. The anklet 108 ( FIG. 1 ) may be sewn to either or both of the spine 120 and the adjacent band 102 .
[0025] In the embodiment of FIG. 3 , the spine 120 extends both on an inside (adjacent the leg) and outside (external) of the lower limb compression garment 100 . In furtherance of the example, the spine 120 includes hook material 122 for engaging with loop material 124 on the bands 102 (the loop material can be on both the inside and outside portions of the bands). An outer layer 126 is also provided, which may be either relatively stiff or rigid, which can facilitate the assembly and fitting of the lower limb compression garment 100 , or may have elasticity which can facilitate the movement of the lower limb compression garment once in place.
[0026] Other embodiments may use one spine, one on the inside or one on the outside. Other embodiments may forego the spine as the hook-and-loop fastener or other connective means lengthwise centrally in each band 102 and overlapping may provide adequate connection to hold the device together as a single unit for application or storage.
[0027] In some embodiments, the spine 120 may also serve to connect the anklet 108 ( FIG. 1 ). In other embodiments, the bands 102 , spine 120 , and/or anklet 108 can be attached using other mechanisms, such as glue or adhesive, snaps, or buttons. Furthermore, the spine 120 can be sewn or otherwise segregated into increments 128 so that it can easily be cut or shortened, as needed. For a lower limb, the spine may be 12, 13, 14, or 15 inches in length with increments, although single lengths of spine for different uses are within the scope of the present disclosure. For use as an upper limb compression device, for example, the spine may preferentially go the entire length of the arm along the outside edge. This may necessitate a longer spine and such permeations are within the scope of the present disclosure. Additionally, the spine may wrap around from one side to the other to allow for attachment of excess length or for additional stability of the device. Additionally, it is understood that other modular configurations exist within the scope of the present disclosure, such as any other attachment of the spine to the compression bands or method of attachment of one band to another. These may include buttons, snaps, zippers, or other methods of attachment.
[0028] Referring now to FIG. 4 , in another embodiment, there are two bands, designated 102 a , 102 b , for each band “level.” These bands 102 a , 102 b interconnect to each other and/or the spine 120 . The spine may include slits 120 a to assist in interconnection of the garment 100 . The interconnectivity of the spine 120 to the bands 102 a , 102 b may be any method of mechanical, chemical, or thermal. In yet another embodiment, a single band ( 102 , FIG. 1 ) can be fed through the slits 120 a to position each band on the spine 120 .
[0029] Referring to FIG. 5 , in yet another embodiment, the spine 120 includes horizontal slits 120 b and an optional cover member 129 . The bands 102 fit against the spine 120 and may or may not attach at positions 122 a for the spine and 112 b for the band. The cover member 129 can then be weaved in and out of the slits 120 b in order to hold the bands against the spine. The cover member 129 may attach just at the ends, or may attach at locations between each band 102 . Again, any interconnections may be temporary or permanent and may include mechanical, chemical, or thermal bonds or a combination thereof.
[0030] Not all of the bands 102 need to be similarly constructed. For example, one of the bands in FIG. 5 , designated with reference numeral 102 c , is formed as a chevron, connecting with the spine 120 at the apex of the chevron. Such shape of a band may be desirable to create a more ergonomic angle on the limb. Such angles are preferably applied perpendicular to the skin, with more angle around the upper and lower curves of the calf than the rest of the garment. Such angles may vary according to limb geometry and garment size. Also, different bands can have different levels of elasticity. This would allow the garment 100 to be placed in different scenarios, such as over a bladder used for pneumatic pumps for preventing deep veinous thrombosis. Also different levels of compression can be provided for bands 102 nearer the ankle (or wrist, or shoulder) than further away from the ankle. This selection of a specific elasticity can therapeutically treat edema or decreasing vein size to prevent blood clots.
[0031] Furthermore, bands 102 can have different amounts of compressions and expansion, either compared to each other or different amounts along the band itself. Using different levels of compression may be desirable for different garments. Further, graduated compression may be accomplished by using bands of various levels of compression in the same garment. For example, generally more compression may be desired in the ankle portion and less proximally for a leg compression garment. By using different band composition to vary the stretch, different levels of compression may be achieved. In another example, a band may have less stretch in the portions that intersect the spine 120 , and more compression near the ends that are used for the locking mechanism 104 . Thus, an assembled device can therapeutically apply varying levels of compression. When the user feels that the band no longer stretches, then the compression becomes different and proportional to the tension placed on the band. The user can thus learn to “dial in” to this difference and so more reliably and predictably apply the desired level of compression. By varying the length and width of a band and/or the composition of the band, any desired level of compression can be created in the band.
[0000] The Anklet 108
[0032] Referring again to FIG. 1 , the anklet 108 can be configured as a sock or stocking, being relatively thin so that a shoe can be worn over the garment. In one embodiment, the anklet 108 is made of a synthetic stretch-fiber fabric such as a Lycra® brand material. In some embodiments the anklet 108 may or may not fasten to the rest of the garment 100 . For example, a compression anklet can be used and placed in position with, but not attached to, the garment 100 .
[0033] Referring now to FIG. 6 , in another embodiment, a footpiece 130 can be used as a different kind of anklet. In one embodiment, the footpiece 130 includes an inner sock-like member 132 of cotton/Lycra blend and three outer bands 134 a , 134 b , 134 c of elastomeric material. Other materials and construction can be chosen in order to alter the compression level of the device. Construction may be made of same materials and layers as in FIG. 2 . In some embodiments, the material may be an elastic or non-elastic material and of one single layer or many overlapping layers.
[0034] The three elastomeric bands 134 a , 134 b , 134 c are arranged so that the first elastomeric band 134 a fastens over the forefoot, the second elastomeric band 134 b is angled at approximately ninety degrees to the surface of the midfoot, and the third elastomeric band 134 c is fastened parallel to the back of the Achilles. In the present embodiment, the third elastomeric band 134 c is unique from the other two in that it can attach in place across, or across and downward onto the dorsum of the footpiece. Thus the design is unique in that it allows to fit a variety of foot sizes and to apply variable compression as desired to be most therapeutic.
[0035] The footpiece 130 also includes a single band 134 c sewn in place in the middle with both free ends with sewn hook material. The hook material may be fastened circumferentially across just below the ankle, or may reach down toward the forefoot and across to the opposite side, for example. The flexibility of this band allows a number of geometries to be accounted for. In one embodiment, the band is just over three inches wide. The length of the band may be any desired length for therapeutic use. For example, lengths of 6 inches, 8 inches, 10 inches, 12 inches, 14 inches, 16 inches, and 18 inches, or other lengths are possible.
[0000] Stockings and Liners
[0036] Referring to FIGS. 1 and 6 , a stocking liner 140 may be provided under the garment 100 to reduce itching and minimize effects of overlapping on the skin. The liner can extend the entire length of the garment 100 , including any ankle 108 or foot piece 130 , or may cover only a portion thereof. The liner 140 can be formed of a cotton/Lycra® blend or other material and may have a foam lining. The foam lining may include sewn channels to follow the body's natural lymphatic drainage lines. The foam lining also may have foam with stitches or carved portions to create a waffle-like pattern in order to facilitate lymphatic drainage in the un-compressed portions. The thickness of such a liner 140 may be quite thick, such as can be achieved with the JoviPak UE-P-AG1 (Tri-D Corporation Kent, Wash.). The foam may include a granular-type material. A fabric cover may also be included on all or part of the foam lining.
[0037] Referring also to FIG. 7 , the liner 140 , shown here being used with an arm compression garment, would have a multiplicity of pressure-applying resilient protrusions, or high pressure areas 142 and channels 144 there between. The channels 144 potentially facilitate lymphatic drainage while reducing interstitial edema along the high pressure areas 142 . The liner 140 , which may be constructed similarly to commercial products known under the brand JoviPak, Tribute™ or Komprex II, may be a cotton or blended material with thicker woven fabric as seen in many commercially available socks.
[0038] Another embodiment of the liner 140 may include one or two layers of cotton or cotton/Lycra blend or another similar woven or formed material, with semi compressible material woven between the inner and out layers of the liner. The liner 140 may also include the channels 144 which are in the form of sewn pockets with openings 146 for insertion of a semi-compressible insert 148 to form the high pressure areas 142 . Such an embodiment may have distinct advantages over other commercially available liners since it may be much thinner but with similar performance. This allows more comfort for long-term wear and improved breathability of the liner 140 . The liner 140 may be designed for a specific use, but may have additional uses under other commercially available compression devices, such as The Cinch (Innovative Medical Solutions, Seattle Wash.), ReidSleeve (Peninsula Medical Inc., Scotts Valley Calif.), short-stretch or medium-stretch bandages, CircAid (San Diego Calif.) or other commercially used products for treatment of edema, venous and lymphedema. The insert 148 is preferentially thin and less than 1 cm, although larger sizes may also be desirable.
[0039] In another embodiment, foam padding can be positioned in-between the liner 140 and the straps 102 . The foam padding can be used to reduce lymphedema. One possibility is to use dense foam such as Komprex foam (Lohmann Rauscher Neuwied, Germany). In this embodiment, the foam is cut into small squares of 0.25 cm to 2 cm along each side. These squares may or may not have a pyramid shape facing the inner layer. These pyramid-shaped areas massage the affected area during wear and can break up fibrotic areas, effectively reducing lymphedema long-term. Alternatively, one solid piece of foam with a grid but out on one side may achieve the same function. Other foam padding includes JoviPak Multi-Purpose pads (Tri-D Corporation Kent, Wash.) or other commercially available products such as the Jovi Le-C-Advi sheet foam liner. Such pads are sewn chips or pieces of polyurethane or similar foam and may or may not have channels sewn into place.
[0000] Business Method
[0040] Referring now to FIG. 8 , the garments 100 discussed above can be provided in response to receiving a customer order form 200 . The form 200 includes an order information section 202 , a shipping information section 204 , a billing information section 206 , a measurement section 208 , and a measurement guide 210 . A customer can obtain and fill out the form 200 where measurements are taken of key components of the affected limb. If the place of assembly for the garment 100 is the same as the place of sale, then the measurements may be compared to pre-stocked components and the proper number and type of components can be selected. The modularity of the garment 100 facilitates a sales facility in having a reduced inventory yet still being able to provide a highly-customized solution.
[0041] Furthermore, the amount of overlap of bands may be varied to accommodate a variety of leg lengths. In one embodiment, the bands 102 are just over three inches in height, and each lower limb compression device may have 4-6 bands, one to two spines 120 , and a footpiece or anklet 108 . Since the spine 120 may be modular, one spine may accommodate an arm or a lower leg. Other spines, such as for an entire lower limb device, may also be provided. In another embodiment, the spine 120 may include a material backing with iron-on interfacing. This will allow quick permanent assembly of a plurality of bands 102 with or without an anklet. This customization can be done at the time of measurement of the actual limb, or can be done at a remote location using the measurement form 200 .
[0042] In some embodiments, one or more of the bands 102 can be overlapped and connected (e.g. sewn together) prior to delivering to a doctor or patient. In other embodiments, some or all of the garment 100 can be sterilized prior to delivery.
[0043] Some embodiments of the form 200 can include information that would allow a doctor or provider to custom select certain bands 102 for different purposes. For example, different levels of edema (e.g., minimal, extreme) can be addressed by selecting an appropriate elasticity of the bands 102 . Also, the height and/or weight of a patient can factor into the selection of band size, placement (e.g., more elastic bands near the ankle) and composition. The bands 102 can include a marker such as a position number that will indicate their placement on the spine 120 .
[0044] The foregoing has outlined features of several embodiments according to aspects of the present invention. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.
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An apparatus for applying pressure to a body part comprising multiple interconnectable bands of compressible or noncompressible material. Optional spine to further interconnect the bands. Interconnectable pieces designed for covering specific body areas. Modular arrangement of the individual components. Customized or off-the-shelf availability of the apparatus.
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BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a tool damage detection device or the like.
An example of a conventional tool damage detection device is disclosed in Japanese Patent Publication No. TOKKAI 2001-38512. As shown in FIG. 6 , this detection device is such that an electric motor 50 is used to detect whether or not a contact bar 51 contacts a body part of a tool 52 which lies within an arc of the contact bar 51 . When the contact bar 51 passes without contacting the body part of the tool 52 , the electric motor 50 senses this as a “damage” situation, and outputs a warning or a stop signal to a machine control section (not shown in the figure).
However, the above-mentioned detector is often used under circumstances wherein a great amount of cutting agents (liquid) come into contact with the detector, or a mist of cutting agent is filled in the air. Since the cutting agents contain considerable amounts of surfactant, they exhibit extremely high permeability and causticity characteristics. As a result, it is necessary to improve the waterproofing of a bearing of the detector. To do this, it is necessary to provide increased amounts of waterproofing which include the use of rubber O-rings, packing, V-seals and so on. However, these measures induce a shortcoming that the resulting friction resists the rotation of the contact bar and the torque output is reduced.
Also, in the case of the above-mentioned detector, since the cutting agents contain surfactants, they exhibit high levels of permeability and causticity. As a result, the durability of the control motor is significantly reduced due to problems such as failure of the motor coil winding insulation or heat generation due to electric overload. Moreover, an expensive electric control section is required. Additionally, detection of any damage (chipping) due to contact with the edge (slope portion) of the tool which lies within the range of the turning of the contact bar, is almost impossible.
The present invention has been proposed in order to solve the above-mentioned problems. The object of the present invention is, therefore, to provide a tool damage detection device which can detect damage of the body part or edge of the tool without problem occurring due to the penetration of the cutting agents or electric overload which result from the provision of waterproofing measures.
Further objects and advantages of the invention will be apparent from the following description of the invention.
SUMMARY OF INVENTION
In order to achieve the above-mentioned purpose, a tool damage detection device according to a first aspect of the present invention detects the presence or absence of damage through the contact of a contact bar which projects in an orthogonal direction from a rotational axis projecting from the main body case, with a tool, and outputs a signal when damage is detected. The rotational axis is rotated by a direct-acting air driving (pneumatically operated) device, so that the durability of the tool damage detection device is not affected by penetration of cutting agents.
Also, in the tool damage detection device according to a second aspect of the present invention, a resilient member such as a torsion spring is used to provide an operative drive connection between the rotational member on which the contact bar is supported and the pneumatically powered direct-acting air driving member. This provision enables impact between the tool and the contact bar to be attenuated.
In addition, in the tool damage detection device according to a third aspect of the present invention, a plunger type contact sensor which detects damage of an edge of the tool, is provided in an outboard end of an arm bar projecting in an orthogonal direction from the rotational axis projecting from the main body case. The tool damage detection device can detect the damage by the amount the edge of the tool is displaced with respect to a sensor contact face.
In the invention according to the first aspect, since the contact bar is rotated by the direct-acting air driving device, there is no need for an electrical control motor. As a result, there is no negative effect due to the penetration of the cutting agents (liquid) containing surfactants or the like. Therefore, the embodiments of the invention can be used without encountering the above mentioned types of problem even in circumstances wherein large amounts of cutting agents (liquid) come into contact with the detector or the detector is exposed to clouds of cutting agents which have been dispersed into the air.
Also, with the embodiments according to the second aspect of the invention, the rotational axis rotates with the sensor part detecting the rotational angle of the contact bar through the coil spring from the rotating member rotating by the direct-acting air driving member, and the contact bar contacts a body of the tool. As a result, the force with which the tool is contacted can be maintained at an adequate level while the impact with the tool can be decreased.
Moreover, with embodiments of the third aspect of the invention, a plunger type contact sensor provided in the arm bar projecting in the orthogonal direction from the rotational axis projecting from the main body case is rotated and stopped at the position corresponding to the edge of the tool. Therefore, these embodiments can detect the damage according to the amount of displacement which occurs until the edge of the tool contacts the sensor contact face.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a device which in accordance with one embodiment of the present invention is provided with a vertically arranged direct-acting air driving member;
FIG. 2 is a perspective view of a rotating cam tube which converts the linear motion of the direct-acting air driving member into rotational motion;
FIG. 3 is an exploded perspective view of a device which in accordance with one embodiment of the invention is provided with a horizontally arranged direct-acting air driving member;
FIG. 4 is a perspective view showing a rack (and pinion) arrangement which converts linear motion of the direct-acting air driving member into rotational motion;
FIG. 5 is a sectional view of a third embodiment of the invention which uses a plunger type contact sensor; and
FIG. 6 illustrates a relationship between the rotation of a contact bar of a conventional device and a tool, which was discussed in the opening paragraphs of the instant disclosure.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Next, an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the invention which is provided with what shall be referred to as a vertically or axially acting direct-acting air driving; FIG. 2 is a perspective view showing a rotating cam tube which converts the linear of movement of the direct-acting air driving member into rotational motion; FIG. 3 is an exploded perspective view of an embodiment of the invention which is provided with what shall be referred to as a horizontally or laterally acting direct-acting air driving member; FIG. 4 is a perspective view of a rack and pinion arrangement which converts the linear motion of the laterally acting direct-acting air driving member into rotational motion; and FIG. 5 is a cross sectional view of the device with a plunger type contact sensor according to the present invention.
In FIG. 1 , the numeral 1 denotes an embodiment of the invention which is provided with a vertically acting direct-acting air driving unit 3 which operates in an axial direction of a main case body or casing 2 and which is disposed below the casing 2 . The direct-acting air driving unit 3 allows a piston 6 to move upward against the bias of a spring 5 in accordance with pressurized air which is supplied through an air hose 4 that is communicated with a source of air under pressure such as an air compressor/valve arrangement (not shown in the figures). When the piston 6 moves upward, a piston or plunger 8 is driven upward via the connecting rod 7 . On the other hand, when there is no pressurized air supplied through the air hose 4 , the plunger 8 returns to its former position under the influence of the bias applied by spring 5 .
In FIGS. 1 and 2 , the plunger 8 is shown to be connected with the piston 6 through the connecting rod 7 and a flexible joint 9 which absorbs any offset between the centers of the piston 6 and the plunger 8 . If offset is not an issue, then the plunger 8 can be connected with the piston 6 without the flexible joint 9 .
When the plunger 8 moves upward by actuation of the direct-acting air driving unit 3 , a roller 10 which is axially supported on the plunger 8 , drives a rotating cam tube 12 to rotate about an axis along which the plunger 8 is reciprocal, via engagement with a spiral (helical) cam groove 11 in which the roller 10 is received (slides) and thus functions as a cam follower. The rotation of the rotating cam tube 12 drives a rotatable member 14 to rotate. The rotatable member 14 is united with the rotating cam tube 12 through connecting means 13 .
The above-described rotatable member 14 drives a sensor drive shaft 16 to rotate through a connection which is established via a coil spring (torsion coil spring) 15 . The sensor drive shaft 16 projects out through an upper surface of the casing 2 . The upper end of the sensor drive shaft 16 is connected with a contact bar 18 which projects at right angles through a cap member 17 that covers the sensor drive shaft 16 .
The contact bar 18 is arranged to contact a body part (side face) of a tool 20 while it is rotating. The contact bar 18 is rotated by way of the torsion which is applied by the coil spring 15 , via the rotation of the rotatable member 14 which is induced by the direct-acting air driving unit 3 . This allows the sensor drive shaft 16 to detect the, rotational angle via the rotation of the contact bar 18 and the generation of contact force between the contact bar and the tool 20 . In this case, the contact bar 18 contacts the body part of the tool 20 with a relatively low contact force and thus reduces shock to the tool 20 .
The sensor drive shaft 16 is supported by the casing 2 through a bearing 19 . Also, a hub-like base portion 21 of the sensor drive shaft 16 has a drum-shape and encloses the rotatable member 14 . One end of the coil spring 15 is connected with the drum-like base portion 21 , and the other end is connected with the rotatable member 14 respectively.
The rotation of the rotatable member 14 rotated by the actuation of the direct-acting air driving unit 3 is transmitted to the sensor drive shaft 16 through the coil spring 15 as noted above. As a result of this structure, when the contact bar 18 contacts the body part of the tool 20 and stops, the rotatable member 14 continues to rotate only for a predetermined rotational angle with the rotating cam tube 12 .
A magnetic switch 22 a and a magnet 22 b are arranged to form a non-contact switch between the inner circumference of the casing 2 and the outer circumference of the base portion 21 of the drive shaft 16 . When the contact bar 18 does not contact the body part of the tool 20 in the middle of the rotation, the magnetic switch 22 a and the magnet 22 b senses it as “damaged”, and output a “damaged signal”. This signal output circuit is not shown in the drawings. On the contrary, when the contact bar 18 contacts the body part of the tool 20 in the middle of the rotation, the tool is judged as “normal”.
Top and bottom end portions of the rotating cam tube 12 are supported on the inner circumference of the casing 2 through bearings 23 a, 23 b, so that smooth rotation is assured. A tube member 25 with a straight or linear groove 24 is provided on the outside of the rotating cam tube 12 (inner circumferential face of the casing 2 ). The straight groove 24 guides an external roller 10 ′ which has the same axis as the roller 10 axially supported by the plunger 8 in the vertical direction. The straight groove 24 of the tube member 25 may be formed directly on the inner circumferential face of the casing 2 . In addition, the straight line groove 24 is made in order to guide the plunger 8 in a vertical direction with the actuation of the direct-acting air driving unit 3 . However, it may be changed to another structure without departing from the scope of the invention.
The rotating cam tube 12 is rotated by moving the plunger 8 up and down with the actuation of the direct-acting air driving unit 3 . However, the rotational angle of the rotating cam tube 12 is determined by the sliding length (stroke) of the piston 6 of the direct-acting air driving unit 3 . The stroke is required to have a certain length because an angle of the spiral or helical groove 11 is increased in order to reduce resistance during the rotation. In this embodiment, the above-mentioned condition is also taken into account.
The non-contact switch consisting of a magnetic switch 26 a and a magnet 26 b is provided on a tube or sleeve member 25 which forms an outer wall of the rotating cam tube 12 and in which the linear groove 24 is formed. This enables the output of the positional signals representing an original (start) point and ending point of the rotation of the rotating cam tube 12 . In this instance also, the output circuit of the positional signals of the rotating cam tube 12 is not shown in the figure.
The direct-acting air driving unit 3 uses pressurized air to rotate the contact bar 18 toward a stop-end from the original point. The contact bar 18 rotates under the influence of the bias provided by the spring 5 between the stop-end and the original point.
However, when the direct-acting air driving unit 3 rotates toward the stop-end from the original point, spring force can be used, and air can be used between the stop-end and the original point. Also, the direct-acting air driving member can be replaced with a double-acting air driving machine.
A second embodiment of the invention is shown in FIGS. 3 and 4 . In this second embodiment direct-acting air driving unit 3 is arranged to operate in the horizontal (i.e. lateral) direction with respect to the casing 2 as shown. The direct-acting air driving unit 3 in this embodiment advances a sliding member 27 in the direction of Y against the spring force of the spring 5 shown in FIG. 4 by the air supplied through the air hose 4 communicated with the air compressor (not shown in the figures). When there is no air supply through the air hose 4 , the sliding member 27 returns to the former position under the bias of spring 5 which has become compressed by the pneumatically induced stroke.
When the sliding member 27 advances, the rotatable member 14 is rotated through a rack 28 forming the body part of the sliding member 27 and a pinion 29 which engages with the rack 28 . The rotatable member 14 continuously rotates the drive shaft 16 projecting from the upper surface of the casing 2 through the coil spring 15 . The drive shaft 16 , is connected with the contact bar 18 so that it projects at right angles through the cap member 17 covering the upper end of the drive shaft 16 . As in FIG. 1 , when the contact bar 18 does not contact the body part of the tool 20 in the middle of the rotation, the contact bar 18 outputs the “damaged” signal.
The casing 2 shown in FIG. 3 , consists of box-shaped upper and lower casing portions 2 a , 2 b which are positioned respect to one another by positioning pins 30 and corresponding pin holes (not shown in the figure). The upper and lower portions 2 a , 2 b are fixed by screw bars 31 in plural positions. As in FIG. 1 , the casing 2 allows the contact bar 18 to rotate through the coil spring 15 from the direct-acting air driving unit 3 and generate the necessary contact force when the contact bar rotates to contact the tool 20 . Also, the casing 2 can reduce the shock to the tool quickly.
A third embodiment of the invention is shown in FIG. 5 . In this embodiment, the arm bar is, which by way of example, comprised of a tubular member 33 and a plunger type contact sensor 35 . The arm bar 33 is connected to the sensor drive shaft 16 which projects out of the casing 2 , and projects in an orthogonal direction through a boss unit 32 . The plunger type contact sensor 35 detects the damage of an edge 34 (in this example, the sloping edge represents a cutting portion), by allowing the arm bar 33 to contact the edge 34 of the tool 20 . In addition, the edge (slope=cutting portion) 34 of the tool 20 is not limited to downwardly curving elements in the manner illustrated.
The rotational angle of the sensor drive shaft 16 is determined by the spiral or helical angle of the spiral groove 11 of the rotating cam tube 12 which is integrated with the rotational angle of the sensor drive shaft 16 . In other words, when the piston 6 moves up against the spring force of the spring 5 in response to pressurized air being supplied through the air hose 4 wherein the direct-acting air driving unit 3 is communicated with the air compressor (not shown in the figure), the plunger 8 is pushed up by way of the connecting bar 7 . As a result, the rotating cam tube 12 rotates in a horizontal direction through the spiral groove 11 wherein the roller 10 axially supported by the vertical axis 8 fits (slides). Also, the drive shaft 16 integrated with the rotating cam tube 12 rotates (revolves) in the horizontal direction only for a certain angle.
However, if the starting and ending points of rotation of the arm bar 33 projecting in the orthogonal direction through the boss unit 32 are predefined in the sensor drive shaft 16 during the actuation of the direct-acting air driving unit 3 , a center of a sensor contact face 35 ′ of the plunger type contact sensor 35 with the arm bar 33 can be precisely stopped directly beneath the edge 34 (corresponding position) of the tool 20 . In this case, the length of the arm bar 33 has to be predefined.
The plunger type contact sensor 35 predefines a distance A between the sensor contact face 35 ′ and the edge 34 of the tool 20 at the ending point of the rotation of the arm bar 33 . If the displacement amount of the edge 34 of the tool 20 relative to the sensor contact face 35 ′ is the same as the above-mentioned defined distance during the detection, the plunger type contact sensor 35 senses that it is “normal”. On the other hand, if the displacement amount of the edge 34 of the tool 20 is large, the plunger type contact sensor 35 senses it as “damaged”, and outputs the damaged signal. The output circuit in this case is not illustrated.
Next, operation of the device 1 according to this embodiment of the present invention with the direct-acting air driving unit 3 which operates in the vertical or axial direction will be explained.
First, air under pressure is supplied from an air compressor or any other suitable source of air under pressure (not shown in the figure) via (for example) a valve or the like. The pressurized air is supplied in the direct-acting air driving unit 3 through the air hose 4 communicated with the pressurized air source (e.g. air compressor). The piston 6 drives the plunger 8 up against the bias of the spring 5 . In an upper movement of the plunger 8 , the rotating cam tube 12 rotates due to the provision of the roller 10 which is supported on the plunger 8 . The rotatable member 14 rotates by this rotation, and the contact bar 18 projecting on the drive shaft 16 rotates via the torque which is applied through the coil spring 15 , and revolves toward the stop-end from the original point. When the contact bar 18 hits the body part of the tool 20 in the middle of the revolution, the contact bar 18 stops. However, the rotatable member 14 still continues to rotate a little further for predetermined rotational angle with the rotating cam tube 12 .
As mentioned in the above, when the contact bar 18 contacts the body part of the tool 20 in the middle of the revolution, the device 1 outputs “normal”. When the contact bar 18 passes without contacting the body part of the tool 20 , the device 1 outputs the “damaged” signal by the operation of the magnetic switch 22 a and the magnet 22 b provided between the base portion of the sensor drive shaft 16 and the case main body. In addition, in this embodiment of the invention, the magnetic switch is used for the signal output. However, the embodiments of the invention are not limited to the use of this type of magnetic switch, and can take the form of contact switches or the like, provided sufficient waterproofing is provided. Also, in the illustrated embodiments, the contact bar has been shown as rotating clockwise, however, the invention is not so limited and the contact bar can rotate tool counterclockwise if so desired.
The embodiments of the invention can be attached to a machine tool such as an automobile, private plane and so on and used as a detection sensor for the damage of the tool or a loss of the edge. Also, since the device 1 of the invention does not use an electric motor, the embodiments of the invention can be used under circumstances wherein a large amounts of cutting agents come in contact with the device and also operate under conditions wherein air is filled with a mist of cutting agents, without difficulty.
Although the invention has been described with reference to only a limited number of embodiments the various modifications and variations which are possible without departing from the scope of the present invention, which is limited only the appended claims, will be self-evident to a person of skill in the art to which the present invention pertains or most closely pertains, given the preceding disclosure.
The disclosures of Japanese Patent applications No. 2004-32756 filed on Feb. 9, 2004 and No. 2004-347683 filed on Nov. 30, 2004 are incorporated herein.
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A tool damage detection device which detects the presence or absence of damage, has a contact bar rotatably supported on a casing; a pneumatically operated air drive device operatively connected with a supply of air under pressure; and a linear-to-rotational motion conversion device operatively interconnects the contact bar and the direct-air drive device. A resilient member is interposed between the contact bar and the conversion device.
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BACKGROUND OF THE INVENTION
The present invention relates to automatic clothes washers and more particularly to a method of washing fabric in a vertical axis clothes washer.
Attempts have been made to provide a automatic clothes washer which provides comparable or superior wash results to present commercially available automatic washers, yet which uses less energy and water. For example, such devices and wash processes are shown and described in U.S. Pat. Nos. 4,784,666 and 4,987,627, both assigned to the assignee of the present application, and incorporated herein by reference.
The basis of these systems stems from the optimization of the equation where wash performance is defined by a balance between the chemical (the detergent efficiency and water quality), thermal (energy to heat water), and mechanical (application of fluid flow through--fluid flow over--fluid impact--fabric flexing) energy inputs to the system. Any reduction in one or more energy forms requires an increase in one or more of the other energy inputs to produce comparable levels of wash performance.
Significantly greater savings in water usage and energy usage than is achieved by heretofore disclosed wash systems and methods would be highly desirable.
SUMMARY OF THE INVENTION
A vertical axis washer system incorporating the principles of the present invention utilizes a basket structure and fluid conduits and valves which complement specifically increasing the level of chemical contributions to the wash system, therefore permitting the reduction of both mechanical and thermal inputs.
The utilization of concentrated detergent solution concepts permits the appliance manufacturer to significantly reduce the amount of thermal and mechanical energy applied to the clothes load, through the increase of chemistry a minimum of thirteen fold and maximum up to at least sixty-four fold, while approximating "traditional" cleaning levels, yet reducing the energy and water usage . This translates to washing with reduced water heating, reduced water consumption, and minimal mechanical wash action to physically dislodge soils. A concentrated detergent solution is defined in U.S. Pat. No. 4,784,666 as 0.5% to 4% detergent by weight. It is anticipated now, however, that a concentrated detergent solution may be as high as 12% by weight.
The present invention contemplates a method of washing fabric in a washer having a wash chamber rotatable about a vertical axis and charged with a detergent solution. The method includes rotating the wash chamber about its vertical axis a number of revolutions sufficient to cause the fabric and detergent solution within the wash chamber to rotate at a speed approximately the same as the wash chamber. The wash chamber is periodically decelerated, causing the fabric and detergent solution to move relative to the wash chamber due to rotational inertia of the fabric and detergent solution. The fabric is tumbled within the wash chamber by impinging the fabric on structures in the wash chamber as the fabric is moving relative to the wash chamber. The above rotating, decelerating, and tumbling steps are repeated for a predetermined period of time. A recirculating spray of concentrated detergent solution is directed on to the fabric during the first period of time as the fabric is rotating with and tumbling in the wash chamber. Finally, the detergent solution is removed from the fabric by spinning and draining the wash chamber.
The structures within the wash chamber include a side wall, a baffle, a floor, and a ramp disposed on the floor. The fabric in the wash chamber tumbles by periodically decelerating the wash chamber, causing the fabric to impinge the floor ramp and travel up the side wall of the wash chamber to impinge the baffle, thereby causing the fabric to tumble within the wash chamber as the wash chamber decelerates.
The structures within the wash chamber further include a baffle on the side wall of the wash chamber. The step of causing the fabric to tumble further includes causing the fabric to impinge the baffle after impinging the fabric on the ramp.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an automatic washer, partially cut away to illustrate various interior components.
FIG. 2 is a partial front elevational view of the washer of FIG. 1 with the outer wrapper removed to illustrate the interior components.
FIG. 3 is an enlarged partial side elevational view illustrating the dispensing tank and associated components.
FIG. 4A is a top view of the automatic washer of FIG. 1 with the lid removed.
FIG. 4B is a top sectional view of an alternate embodiment the basket taken just below the level of the top panel.
FIG. 4C is an alternate embodiment of the basket in a top view with the lid removed.
FIG. 4D is an alternate embodiment of the basket in a top sectional view taken just below the level of the top panel.
FIG. 5 is a side sectional view of the washer.
FIG. 6 is a schematic illustration of the fluid conduits and valves associated with the automatic washer.
FIG. 7 is a flow chart diagram of the steps incorporated in the concentrated wash cycle.
FIG. 8A is a side sectional view of the use of a pressure dome as a liquid level sensor in the wash tub.
FIG. 8B is a sectional view of the wash tub illustration an electrical probe liquid level sensor.
FIG. 9A is a flow chart diagram of a recirculation rinse cycle.
FIG. 9B is a flow chart diagram of a swirl rinse cycle.
FIG. 9C is a flow chart diagram of a flush rinse cycle.
FIG. 10 is a side sectional view of the piggy back recirculating and fresh water inlet nozzles.
FIG. 11 is an isolated perspective view of an individual valve member.
FIG. 12 is an isolated perspective view of a valve sheet.
FIG. 13 is an isolated perspective view of the valve member of FIG. 11 in an open position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Washer And Fluid Flow Path Construction
In FIG. 1, reference numeral 20 indicates generally a washing machine of the automatic type, i.e., a machine having a pre-settable sequential control means for operating a washer through a preselected program of automatic washing, rinsing and drying operations in which the present invention ma be embodied. The machine 20 includes a frame 22 carrying vertical panels 24 forming the sides 24a, top 24b, front 24c and back 24d (FIG. 5) of the cabinet 25 for the washing machine 20. A hinged lid 26 is provided in the usual manner to provide access to the interior or treatment zone 27 of the washing machine 20. The washing machine 20 has a console 28 including a timer dial 30 or other timing mechanism and a temperature selector 32 as well as a cycle selector 33 and other selectors as desired.
Internally of the machine 20 described herein by way of exemplifications, there is disposed an imperforate fluid containing tub 34 within which is a spin basket 35 with perforations or holes 36 therein, while a pump 38 is provided below the tub 34. The spin basket 35 defines a wash chamber. A motor 39 (FIG. 5) is operatively connected to the basket 35 to rotate the basket relative to the stationary tub 34.
Water is supplied to the imperforate tub 34 by hot and cold water supply inlets 40 and 42 (FIG. 6). Mixing valves 44 and 45 and the illustrated production dispenser design are connected to conduit 48. This triple dispenser also contains a by-pass around valves 44 and 45, which terminates in mixing valve 47 which is also part of the standard production dispenser. Mixing valve 47 is connected to manifold conduit 46. Conduit 48 leads to a fresh water inlet housing or spray nozzle 50 mounted in a piggy back style on top of a recirculating water inlet housing or spray nozzle 51 adjacent to the upper edge of the imperforate tub 34 The nozzles 50, 51 which are shown in greater detail in FIG. 10, may be of the type disclosed in U.S. Pat. No. 4,754,622 assigned to the assignee of the present application and incorporated herein by reference, or may be of any other type of spray nozzle. A single nozzle would be a preferred approach if U. L. and other certifying tests and standards could be satisfied.
Surrounding a top opening 56 above the tub 34, just below the openable lid 26, there are a plurality of wash additive dispensers 60, 62 and 64. As seen in FIGS. 1 and 4A, these dispensers are accessible when the hinged lid 26 is in an open position. Dispensers 60 and 62 can be used for dispensing additives such as bleach for fabric softeners and dispenser 64 can be used to dispense detergent (either liquid or granular) into the wash load at the appropriate time in the automatic wash cycle. As shown schematically in FIG. 6, each of the dispensers 60, 62 and 64 are supplied with liquid (generally fresh water or wash liquid) through a separate, dedicated conduit 66, 68, 70 respectively. Each of the conduits 66, 68 and 70 may be connected to a fluid source in a conventional manner, as by respective solenoid operated valves (72, 74 and 76 FIG. 6), which contain built-in flow devices to give the same flow rate over wide ranges of inlet pressures, connecting each conduit to the manifold conduit 46.
A mixing tank 80, as shown in FIGS. 1 and 3, forms a zone for receiving and storing a concentrated solution of detergent during the wash cycle, and is used in some embodiments of the invention. As will be described in greater detail below, the mixing tank 80 communicates at a top end with the wash tub 34 and at a lower end communicates with the pump 38, a drain line or conduit 82 and a recirculating conduit 84.
The mixing tank 80 is shown in greater detail in FIGS. 2, 3 and 4B where it is seen that the tank 80 has an arcuate rear wall 110 conforming generally to the circumferential wall 96 of the tub and a somewhat more angular front wall 112 generally paralleling, but being spaced slightly inwardly of the right side wall 24a and the front wall 24c of the washer cabinet 14. Thus, the tank 80, which is secured to the exterior surface of the tub, fits within a normally non-utilized space within the front right corner of the washer cabinet 25.
The tank 80 has a generally curved, closed top wall 114 with a port 116 positioned at an apex 118 thereof, which port 116 communicates with the interior of the tub 34 through a short conduit 119. The tank 80 also has a curved lower wall 120 with a port 122 at a lowermost point 124. The port 122 communicates, through a conduit 126 With a suction inlet 127 of the pump 38. A selectively actuatable valve mechanism 128 provides selective communication through the passage represented by the conduit 126. Such a valve 128 can be of any of a number of valve types such as a solenoid actuated pinch valve, a flapper valve, or other type of controllable valve mechanism.
A third port 130 is provided through the front wall 112 of the tank 80, adjacent to the rear wall 110 and adjacent to the bottom wall 120. This port 130 communicates by means of a conduit 132 with the conduits 82 and 84 (FIG. 6) which, as described above, are associated with the pump 38, a drain 134 and the recirculating nozzle 51.
The detergent dispenser 64 has openings 136 through a bottom wall 137 thereof which communicate with a space 138 between the basket 35 and tub 34. As described above, the detergent dispenser 64 is provided with a supply of fresh water through conduit 70. The three way valve 47 (FIG. 6) is connected to conduit 70 so as to direct a flow of fresh water to either the detergent dispenser 64, the fresh water spray nozzle 50 directed to the interior of the wash basket 35, or both. Other types of detergent dispensers can, of course, be used with the present invention, including dispensers which hold more than a single charge of detergent and dispense a single charge for each wash cycle.
Positioned within the tub 34, n®ar a bottom wall 139 thereof is a liquid sensor means which may be in the form of a liquid level sensor 140. Such a sensor can be of a number of different types of sensors including a conductivity probe 142 (FIG. 8B), a temperature thermistor 144 (FIG. 6) or a pressure dome 146 (FIG. 8A). Regardless of the sensor type, the liquid sensor type, the liquid sensor must be able to detect either the presence of liquid detergent solution and/or the presence of suds within the sump. A sensor which detects the depth of liquid within the sump may also be utilized. When the sensor makes the required detection, it sends an appropriate signal to a control device 141, as is known in the art, to provide the appropriate control signals to operate the various valves as required at that portion of the wash cycle. As is described in greater detail below, the liquid sensor 140 is used to maintain a desired level of wash liquid within the tub 34 during the recirculating portion of the concentrated wash cycle.
The probe sensor 142, shown in FIG. 8B, consists of two insulated stainless steel electrodes 148 having only the tips 150 exposed in the tub 34. When the detergent solution or suds level raises high enough to contact both electrodes, the low voltage circuit is completed indicating the sensor is satisfied.
A thermistor system 144, as generally indicated in FIG. 6, is also located in the tub 34 and is triggered when the water or suds level rises to the designated level, thus cooling the sensor element.
A pressure dome sensor 146, as shown in FIG. 8A and FIG. 6, is similar to pressure domes normally utilized determining liquid level within an automatic washer tub, however it is the positioning of the dome near the bottom of the tub 34, rather than on the upper side of the tub which is the major difference between its usage here and its traditional usage. If a pressure dome sensor 146 is utilized, it must have a setting for spin/spray usage. An indirect inference of water level in the swirl portion of the cycle based o the level of the detergent liquor can be used via algorithms. A pressure dome sensor may also be beneficial in some embodiments of the invention as a sensor to detect an over sudsing condition. If the suds level is too high, then the sensor does not reset. The failure to reset is a means for terminating a spray/spin wash proceeding with the swirl portion of the wash cycle.
Basket Construction
The swirl washer basket 35 has several alternate configurations. Preferably, in each of the configurations, the washer basket 35 utilizes agibasket technology including the lack of a central vertical agitator or stationary center structure.
In each of the preferred arrangements there is at least one baffle 200 (FIG. 4A) which projects inwardly of the annular side wall 202 of the wash basket 35. The baffle has a pair of vertically disposed curved surfaces 204a, 204b which extend from the basket side wall 202 to a point 206 inward of the side wall. The baffle surfaces 204a, 204b may be flush with the basket side wall 202 at a vertical edge 208 of the baffle. The baffle 200 may join the basket wall 202 at a second, horizontally spaced vertical edge 210 at an angle of approximately 90° thus defining a vertical wall 212. This type of a baffle is used for one way or unidirectional rotation during the swirl wash portion of the wash and/or rinse cycle.
A second embodiment of a baffle 220 (FIG. 4C) again has a pair of vertically disposed surfaces 222a, 222b thereon which extend away from the side wall 202 of the basket to a point 224 inward of the side wall 202. The baffle surfaces 222a, 222b may be flush with the side wall 202 at a first vertical edge 226 thereof as well as at a second horizontally spaced vertical edge 228. This second type of baffle will permit bidirectional rotation of the wash basket 35 during the swirl wash or swirl rinse portions of the wash cycle.
With either of these types of baffles, either a single baffle may be used (FIGS. 4A and 4C) or, if desired, multiple baffles (FIGS. 4B and 4D) may be used to provide additional balance to the wash basket during the wash cycle.
In the preferred arrangements, there is provided at least one ramp 230 (FIGS. 4A-4D) on a bottom wall 232 of the basket 35. The ramp 230 is positioned adjacent to, but below the baffle 200. The ramp has a substantially horizontal sloped surface 234 thereon which extends from said bottom wall 232 to a point 236 above the bottom wall. The ramp surface 234 may be flush with the bottom wall along one horizontal edge 238 of the ramp. In one embodiment (FIGS. 4A and 4B) a second horizontal edge 240 of the ramp may join the bottom wall 232 at approximately 90° thus defining a vertical wall 242. In an alternate embodiment (FIGS. 4C and 4D), there is a ramp 250 positioned on the bottom wall 232 of the basket 35 which has a sloped ramp surface 254 extending from the bottom wall 232 to a point 256 spaced above the bottom wall. The ramp surface 254 may be flush with the bottom wall 232 at one horizontal edge 258 thereof and may also be flush with the bottom wall 232 at a second horizontal edge 260.
The first type of ramp 230 is to be used in conjunction with the first type of baffle 200 described above for one way or unidirectional rotation of the wash basket during the swirl wash and/or swirl rinse cycles. The second type of ramp 250 is to be used in conjunction with the second type of baffle 220 for either unidirectional or bidirectional rotation of the wash basket. Preferably there is a ramp associated with each baffle with the ramp positioned below the baffle and with the ramp surface 234, 254 leading upwardly toward the baffle surface 204, 222.
As will be described in greater detail below, during the swirl wash and/or swirl rinse portions of the wash cycle, the fabric load within the wash basket is caused to move relative to the wash basket and the geometry of the ramps and baffles is such that the fabric load will slide upwardly along the ram surface 234, 254 to engage the baffle surface 204a, 222a which will cause the clothes to tumble over one another in a flexing action to reposition the fabric within the fabric load.
The basket also has an angled barrier 270 positioned near a top 272 of the basket 35 to prevent the wash liquor and/or fabric load from traveling too high in the basket. The basket wall 202 may be sloped outwardly up to 20°-30° from bottom to top. Both the free wash liquor and the fabric loads generally travel to the point of maximum basket diameter during spinning or rotation of the wash basket and thus the inwardly angled barrier 270 would prevent further upward travel.
Utilization of vertical versus sloped basket wall 202 and/or flat versus concave versus convex basket bottom wall 232 offers varying degrees of successful clothes tumbling.
Valve Construction
During the swirl wash and/or swirl rinse portions of the wash cycle it is desireable to keep as much of the wash liquor in the basket 35 as is possible. To that end, the wash basket 35 may be constructed in a nearly solid manner, that is, with a minimal number of perforations through the side wall 202. This will significantly reduce the flow of wash liquor from the wash basket 35 into the wash tub 34.
To enhance the maintaining of the wash liquor in the wash basket 35, the perforations 36 in the wash basket 35 may be provided with valves 300 which restrict the fluid flow through the perforations during the tumble portion of the swirl wash and/or swirl rinse, but permit extraction and fluid flow therethrough during higher spin speeds. These valves 300 may take the form of individual elastomeric sheet-like components 302 which are attached around the basket 35 or they may be grouped into functional units occupying larger areas, such as bands or sheets 304 of elastomeric material. The valve openings are formed as slits or cuts 306, 308 in the elastomeric material. The individual components 302 or sheets 304 can be attached to the outer surface of the basket 35 by appropriate fasteners, or adhesives, generally in the peripheral areas of the valves 300, leaving the central areas where the slits 306, 308 are located, free to flex. When the basket 35 is stationary or is slowly rotating, the slits or cuts 306, 308 will remain virtually closed, thus preventing fluid passage. However, when the rotation of the basket 35 exceeds some predetermined speed, the elastomeric material will deform, since it is attached only around its periphery or at least in portions spaced away from the slits 306, 308, thus the area in which the slit is positioned will flex outwardly due to centrifugal force, opening the slit as shown in FIG. 13. In this condition the valve 300 is open and fluid flow therethrough is permitted.
Although the valves 300 illustrated have only a single linear slit 306, 308, the particular geometry of the valve opening and size can be changed to provide the desired flow therethrough upon reaching some predetermined rotational speed. For example, multiple slits in the form of crosses or stars may also be used.
While valves of this type may provide some control of detergent liquor leaving the basket 35 for the tub 34, they also introduce potential problems with the build up of lime, water minerals, foreign objects and large insoluble soil particles. Thus, the particular geometry for the slits 306, 308 and the particular size of the slits required to overcome these potential problems will be dependent upon the material selected for the valve body.
An optional in-line water heater 40 offers the ability to increase the concentrated wash liquor to an elevated temperature level, thus providing high temperature wash performance at the reduced cost of heating one to one and half gallons of water during the high detergent concentration wash cycle and four to eight gallons of water during the tumble wash cycle. This compares to the cost of heating twenty to twenty-two gallons of water in a traditional washer. The controlled use of an in-line heater 400 combined with high concentrated wash liquor offers special opportunities for specific optimization of detergent ingredients which are activated only in specific temperature ranges. Furthermore, the elevated water temperatures offer the ability to specifically target oily soil removal and reduce the build-up of both saturated and poly-unsaturated oils in fabrics laundered in cold water.
The use of an in-line lint, button, sand and foreign object trap or filter 402 significantly reduces the potential for problems associated with recirculating fluid systems carrying soils and foreign materials. Such a filter is disclosed in U.S. Pat. No. 4,485,645, assigned to the assignee of the present invention, and incorporated herein by reference. Such optional devices would be utilized in a preferred system.
Wash Cycle
An improved wash and rinse cycle is provided in accordance with the present invention and is shown schematically in FIG. 7. In step 500, the washer is loaded with clothes as would be standard in any vertical axis washer. In step 502, the detergent; liquid, powdered, and/or other detergent forms, is added to the washer, preferably through a detergent dispenser, such as the detergent dispenser 64 illustrated, and mixing tank, such as tank 80, at the dosage recommended by the detergent manufacturer. It is possible to add the detergent directly to washer through the basket or directly into the tub through a direct path. The consumer then selects the desired cycle and water temperature in step 504.
The washer is started and the washer basket 35 begins a low speed spin. The preferred speed allows uniform coverage of the concentrated detergent liquor onto the clothes load. A 3-way drain Valve 166 and a 3-Way detergent mixing valve 170 are turned on and the detergent tank control valve 128 and the detergent water valve 76 are opened. A time delay (approximately 30 seconds) is used to input wash water after which the detergent water valve 76 is closed. As the washer fills, the detergent is washed from the dispenser 64 into the tub 34, past the drain and mixing tank valves 166, and into the mixing tank 80. A time delay (approximately 15 seconds) provide mixing of the detergent with wash water by recirculating the solution in a loop controlled by the valves as indicated by step 506.
In step 508, the detergent tank control valve 128 is closed and a time delay of approximately 15 seconds, but dependent on the size of the mixing tank 80, causes the mixing tank to fill with the detergent solution. The detergent mixing valve 170 is turned off permitting the detergent solution to leave the closed loop and to be sprayed onto the spinning clothes load via the lower nozzle 51 in a piggy back arrangement or one of two nozzles in separate nozzle arrangements. This concentrated detergent solution is forced through the clothes load and through the basket holes due to the centrifugal forced imparted by the spinning basket with potential significant contributions by mechanical fluid flow through the fabric defined by the pumping rate of the detergent liquor. The solution then travels through the basket 35, into the tub 34, down through the pump 38 to be sprayed through the nozzle 51 creating a recirculation loop. The preferred system utilizes a pump exclusively for the recirculation. This ensures sufficient concentrated liquid flow rates without losses due to slower pump speeds associated directly with the drive system. Less effective systems could also use the main pump of the wash system. The process described above utilizes a perforated washer basket, but a nearly solid basket with holes strategically positioned could be used provided the nozzle design provides uniform coverage to the entire clothes load. Such a nozzle design is disclosed in U.S. Pat. No. 4,754,622, assigned to the assignee of the present application, and is incorporated herein by reference.
This step concentrates the effectiveness of the chemistry thus permitting maximum soil removal and minimum soil redeposition even under adverse washing conditions. The high concentrations of detergent ingredients significantly increases the effectiveness of micelle formation and sequestration of oily and particulate soils and water hardness minerals, thus providing improved performance of surfactants, enzymes, oxygen bleaches, and builder systems beyond level achievable under traditional concentrations.
The water level sensor 140, located near the tub bottom, begins to monitor water level concurrent with the opening of the detergent mixing valve 170. Water level control is critical in the swirl washer. Too much detergent solution added will create an over sudsing condition by allowing the spinning basket to contact detergent solution in the bottom of the tub. The preferred method of control is to maintain a minimum level of detergent liquor in the bottom of the tub through the water level sensor. While results suggest that some type of tub modifications (resulting in a sump) permits the HP swirl to function under a wide range of conditions, there are many more common conditions which do not require a tub sump.
A satisfied sensor 140 indicates the system does not require any additional detergent solution at this point in the cycle and the detergent tank valve 128 is closed to maintain the current level of detergent. A satisfied water level sensor 140 early in the wash cycle generally indicates either a no clothes load situation or a very small clothes load. If the sensor is not satisfied, then the detergent tank control valve 128 is opened permitting the addition of detergent solution followed by a five second time delay before again checking the water level sensor 140. If the sensor 140 is satisfied, the detergent tank control valve 128 is closed to maintain the new level of detergent and a thirty second time delay begins to permit the clothes load a chance to come to equilibrium with respect to water retention and the centrifugal forces of extraction created by the spinning basket.
The concentrated wash portion of the cycle (step 508) continues for a time specified by the cycle type. That is, a cycle seeking maximum performance may recirculate the detergent solution through the clothes for 14 minutes or more, while a more delicate or less soiled load will attempt to minimize the length of spinning. The water level sensor 140 monitors the tub 34, adding additional detergent solution from the mixing tank 80 a required. The larger the clothes load the more detergent solution is required. Once the mixing tank 80 is emptied, fresh water is added through the detergent water valve 76 as required by the water level sensor 140.
Swirl Wash Cycle
The spin/recirculation portion of the cycle is terminated after the designated time and the detergent tank control valve 128 is opened with a five second time delay to permit the draining of any remaining detergent solution into the tub 34. The detergent mixing valve 170 is turned on and the detergent water valves and water fill valves 47, 76 are opened to rinse out the detergent mixing tank 80 and begin the first dilution fill.
The fill volume for the swirl wash for step 510 can be indirectly inferred through volume of water used in the concentrated spray wash portion of the cycle in a system utilizing computer control. In more traditional electromechanically control systems, some other method or methods must be used to regulate the fill; i.e., flow regulated timed fill for maximum load volumes, motor torque, and pressure switches.
A water inlet valve 45 is opened to continue the swirl fill through the upper piggy back nozzle 50 (or second nozzle in the separated arrangement) until the water level sensor 140 or other appropriate sensing method is satisfied. Once satisfied, the open valves 45 are closed and the agibasket swirl action begins. The total fill is based on only enough water to slightly suspend the fabric in the wash liquor. This translates to approximately four to six gallons of water for clothes loads ranging in size up to twelve pounds. The water volume requirements increase with increased clothes load size, and uncontrollable parameters include clothes load and fiber composition. The reduction in friction due to a water film between the clothes and the basket appear critical for adequate movement by the clothes load to assure sufficient removal of the suspended and sequestered soils.
Although the concentrated detergent solution is diluted somewhat by step 510, the dilution is not so great as to reduce the detergent concentration to a previously normal concentration of 0.06% to 0.28%. Rather, the detergent concentration remains at an elevated level during the swirl wash step 512. Thus, the extent of mechanical wash action required in step 512 following the concentrated wash step 508 is now significantly reduced relative to traditional systems.
Once the basket 35 has filled the desired amount with water, the basket accelerates slowly to a predetermined speed dependent on the size and number of basket holes, and the leakage rate thru the valves. The acceleration may take numerous basket revolutions to achieve the preferred speed where the clothes travel up the side wall 202 of the basket with the assistance of the floor ramp 230, 250, the shape of the basket side wall 202 and the effects of centrifugal forces. The basket 35 is then rapidly decelerated. The clothes load continues to travel in the original direction of rotation due to the contained inertia. The resulting force carries the clothes load over the ramp 230, 250 and in contact with the arcuate slope 204a, 222a of the side baffle 200, 220. A gentle tumbling and rolling motion by the clothes load results. Over several acceleration and deceleration cycles, garments previously on the bottom now command a position on top of those garments previously located on the top.
While the utilization of a mechanical brake may be used to achieve the deceleration of the basket, a brake is not necessary. Alternately the direction of the motor may be reversed for some number of revolutions resulting in the transfers of the kinetic energy of the spinning basket to kinetic energy in the opposite direction and potential energy in the form of heat transfer to the motor. This energy could also be utilized to provide additional heating of the wash bath, further improving washability and offering optional heated soaks.
Other designs might transfer the energy to a spring mechanism (not shown) where the energy could be re-converted to kinetic energy to accelerate the basket 35 in the opposite direction in systems utilizing bi-directional ramps 250 and baffles 220. In unidirectional systems the basket 35 would repeat the acceleration in the original direction followed by the reversing. Still other bi-directional system could simply apply the steps of the first acceleration in the opposite direction.
The utilization of the recirculated spray throughout the tumble portion of the swirl wash recycles wash liquor draining through holes 36 in either the fully perforated basket or the nearly solid basket provides water conservation, and further assists in the application of wash liquor flow through and over the wash load. The hardware utilized for the concentrated spray wash portion of the cycle effectively fits the requirements.
The gentle tumbling wash action alone, even at this elevated detergent concentration, provides barely enough mechanical energy input to offer consumers minimally acceptable wash performance. Thus, the preferred cycle includes the use of a concentrated detergent solution wash step as described above.
The type and length of agibasket swirl action (repeated acceleration and deceleration steps) varies with the cycle desired. For example, maximum time may be selected for maximum soil removal, while lesser times offer less fluid flow and fabric flexing for delicates, silks, wools, sweaters, and other fine washables. If bleach is being added, then valves 47, 74 are opened to allow a reduced amount of liquid chlorine bleach. The physical size of the bleach dispenser 62 can be used to prevent over dosage or a bulk dispenser can be used to regulate dispensing at the appropriate ratio to the volume of water used in the concentrated detergent solution swirl portion of the wash cycle.
The end of the swirl wash is characterized by a neutral drain followed by complete extraction of wash liquor from the clothes load, basket 35 and tub 34 in step 514. The spin speeds are staged so that the load balances itself and reduces the undesired opportunities for suds lock conditions.
All systems described above can use either spray, swirl, flush rinses, and/or combinations for effective rinsing and water conservation.
The Rinse Cycle
Recirculated Spray Rinse Cycle
The recirculated spray rinse portion of the cycle, as illustrated in FIG. 9A, is a feature for any vertical axis washer. Its preferred usage is in combination with concentrated detergent solution concepts, but is not limited to those designs or methods. The exact hardware utilized for high performance spray washing can be utilized without modification to provide rinsing performance comparable to a classical deep rinse of twenty-two gallons. The recirculated spray rinse cycle uses six to eight serial recirculated spray rinse cycles, consuming approximately one gallon of water each, to provide rinsing, defined by removal of LAS containing surfactants, to a level comparable to that achieved by a deep rinse. Ten or more spray rinses will provide rinse performance superior to a deep rinse.
The basket continues to spin after the final extract of the wash liquor with a fifteen second time delay to assure that all of the wash liquor has been pumped down the drain as shown in step 520. In step 522, the cold water valve 45 is opened until the water level sensor 140 is satisfied and then closed.
In step 524, the fresh water is sprayed directly onto the spinning clothes load. The water dilutes the detergent in the clothes as it passes through the load and basket. The rinse water drains down into the tub and is pumped back through the lower nozzle 51 to form a recirculation loop. The solution extracts additional detergent from the load with each pass. Each recirculation loop is timed delayed thirty seconds, after which the drain valve 166 is turned off and the solution is discharged to the drain as shown in step 526. The drain valve 166 is turned on and the spray rinse loop is repeated for the specified number of spray recirculations.
On the last spray rinse the fabric softener valve 72, and water fill valve 47 are opened for thirty seconds permitting the fabric softener to be rinsed into the tub 34 and pump 38. Water valve 47 and fabric softener valve 72 are closed and the fabric softener is mixed with the last recirculating rinse water. The resulting solution is sprayed onto the clothes load in a recirculation loop for an additional two minutes to assure uniform application of the fabric softener. Additional fresh water is added through the cold water fill valve 4 if the water level sensor 140 becomes unsatisfied. In the final step 526, the drain valve 166 is turned off permitting the final extraction of water and excess softener for sixty seconds.
Swirl Rinse
The swirl rinse cycle shown in FIG. 9B utilizes the hardware described above for the swirl portion of the wash without modification. In this case two swirl rinses using four to eight gallons of water each are used to equate to the performance of one conventional deep rinse utilizing twenty-two gallons of water. The swirl rinse offers opportunities for more uniform application of fabric softener products than spray rinse in the second rinse.
The basket 35 continues to spin after the final extract of the wash liquor with a fifteen second time delay to assure all of the wash liquor has been pumped down the drain as shown in step 530. In step 532, the cold water valve 45 is opened until the water level sensor 140 is satisfied and then is closed. Other sensing methods may be used. This is approximately four to eight gallons of water. The fresh water is sprayed directly onto the clothes load while the basket accelerates and decelerates as described in the swirl wash section. The water dilutes the detergent in the clothes as it passes through the load and basket 35. The length of the swirl rinse may utilize two rinses of approximately four minutes to approximate a deep rinse. Each swirl rinse loop is timed and followed by a drain and extraction (step 536).
On the last swirl rinse the fabric softener valve 72 and cold water fill valve 47 are opened for thirty seconds permitting the fabric softener to be rinsed into the tub 34 and pump 38. These valves are then closed and the fabric softener is mixed with the last recirculating swirl rinse water. The resulting solution is sprayed and swirled onto the clothes load in a recirculation loop for an additional two minutes to assure uniform application of the fabric softener. In the final step 536, the drain valve 166 is turned off permitting the final extraction of water and excess softener for sixty seconds.
Spray Flush Rinse Cycle
Spray flush as shown in FIG. 9C offers a less than optimum performance option. The limiting parameter for this system results from the lack of uniform spray coverage and problems associated with the lack of guaranteed water line pressures. The design does not require any additional hardware and consumes relatively small volumes of water in matching the rinse performance of a deep rinse.
In step 540 the basket 35 continues to spin after the final extract of the wash liquor with a fifteen second time delay to assure all of the wash liquor has been pumped down the drain. The cold water valve 45 is opened until the timer is satisfied and then closed. In step 542 the fresh water is sprayed directly onto the spinning clothes load and directly down the drain by means of the closed drain valve 166. On the last flush spray rinse the fabric softener valve 72 and fill valve 47 are opened for thirty seconds permitting the fabric softener to be rinsed into the tub 34 and pump. Water valve 47 and fabric softener valve 72, are closed and the fabric softener is mixed with the last flush rinse water. The resulting solution is sprayed onto the clothes load in a recirculation loop for an additional two minutes to assure uniform application of the fabric softener. Additional fresh water is added through the cold water fill valve 45 if the water level sensor 140 becomes unsatisfied. The drain valve 166 is turned off permitting the final extraction of water and excess softener for sixty seconds in step 544.
As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.
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A method of washing fabric in a washer having a wash chamber rotatable about a vertical axis and charged with a detergent solution is provided. The wash chamber is rotated about its vertical axis a number of revolutions sufficient to cause the fabric and detergent solution within the wash chamber to rotate at a speed approximately the same as the wash chamber. The wash chamber is periodically decelerated to cause the fabric and detergent solution to move relative to the wash chamber due to rotational inertia of the fabric and detergent solution. The fabric is caused to tumble within the wash chamber by impinging the fabric on structures in the wash chamber as the fabric is moving relative to the wash chamber. The steps of rotating, decelerating, and tumbling are repeated for a predetermined first period of time. A recirculating spray of concentrated detergent solution is directed on to the fabric during the first period of time as the fabric is rotating with and tumbling in the wash chamber. Finally, the detergent solution is removed from the fabric by spinning and draining the wash chamber.
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BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention generally relates to software quality. More specifically, the present invention concerns ensuring quality of a software application across a number of different operating platforms with different system architectures.
[0003] 2. Description of the Related Art
[0004] Historically, software applications were authored exclusively for a single hardware platform or operating environment. For example, a word processing application might have been authored exclusively for a personal computer running a Windows® operating system (OS). Similarly, an Internet-based music store application might have been authored exclusively for a Macintosh computer running a Mac® OS.
[0005] Video games were no different as many game titles were exclusive to a particular gaming platform. In some instances, video games were authored by the manufacturer of the gaming platform. In other instances, however, video game designers and publishers were contractually obligated to exclusively provide a particular game title to a single manufacturer and their particular game platform.
[0006] As the variety of gaming platforms has increased and the total number of platforms in the hands of consumers has proliferated, there has been an increased demand for content (i.e., software applications such as video games). While hardware manufacturers continue to produce certain exclusive game titles, the majority of software application development and video game design has become the realm of independent game studios such as Rockstar Games and Vivendi Games. The increased demand for content by the consumer marketplace—which includes multiple game platforms—as well as the increased quality of video games has allowed game studios to wield increased negotiating clout. As such, it has become increasingly common for a single game author to develop their game for multiple gaming platforms as cross-platform availability is demanded by the consumer. Hardware manufacturers have been forced to comply with this increased negotiating power of game designers in order to ensure they have the most desired game titles available for their particular platform.
[0007] All the while, competition between platform manufacturers remains intense. Despite the fact that certain platforms (such as the PlayStation® 3 from Sony Computer Entertainment Inc.) are technically superior in almost every way to those of their competitors (such as the Microsoft® X-Box), software applications such as video games are increasingly without a native hardware platform or operating environment. Game designers increasingly provide the same title and ‘port’ it across multiple platforms instead of writing the game in an optimized way for the specific architecture of a particular platform. As such, a game title may perform better on one platform versus another due to the particularities of how the title was authored.
[0008] With competition remaining intense, there is a need in the art to ensure that a common game title meets or exceeds quality metrics on one platform versus a competing platform.
SUMMARY OF THE INVENTION
[0009] A further claimed embodiment of the present invention ensures compliance with a contractual obligation related to quality of service in software development for a first platform. The method includes negotiating with a software developer for development of a software title, the software developer being permitted to or having already entered into a contract with another entity for development of the software title on a second platform. The second platform has different system architecture from that of the first platform. A quality of service metric associated with the software title. The parties enter into the contract for development of the software in accordance with said terms including a provision prohibiting results of the quality of service metric as measured on the first platform from being less than the results of the quality of service metric as measured on the second platform.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 illustrates an exemplary method for ensuring quality of a software title developed for multiple platforms.
[0011] FIG. 2 illustrates an exemplary system for ensuring quality of a software title developed for multiple platforms.
[0012] FIG. 3 illustrates an exemplary method for ensuring compliance with a contractual obligation related to quality of service in software development for a first platform.
DETAILED DESCRIPTION
[0013] FIG. 1 illustrates a method 100 for ensuring quality of a software title developed for multiple platforms. In step 110 , a metric is established. The metric of step 110 is associated with the software title.
[0014] The metric of step 110 may include video analysis. For example, video analysis may include a determination made with respect to video quality. The video analysis may also pertain to determinations made with respect to video conferencing between users in a communication network and latency between conferees. Video analysis determinations may also involve latency between an audio stream associated with the analyzed video.
[0015] Video analysis metrics are also inclusive of determinations made with respect to average frame rate, signal-to-noise ratio (SNR), and peak signal-to-noise ratio (PNSR). Metrics may also be selected for the purpose of video analysis with respect to UQI, VQM, PEVQ, SSIM and CZD. A correlation coefficient may also be involved in video analysis. This correlation coefficient may be selected from the likes of linear correlation coefficient, Spearman's rank correlation coefficient, Kurtosis, Kappa coefficient and Outliers Ratio.
[0016] The metric involved in step 110 may also or alternatively involve audio analysis. The audio analysis may include a determination made with respect to sampling rate. Audio analysis is also inclusive of a determination made with respect to a range of sampled sound. Audio analysis may, too, include a determination made with respect to conversions in a sound production unit. Audio analysis may, in some instances, involve a determination made with respect to an ITU R468 weighting curve.
[0017] Like the metrics associated with video analysis, certain audio-oriented determinations may be made in the context of a conferencing environment. For example, audio analysis may include a determination made with respect to latency in an audio conference environment between users in a communication network. Certain audio-based analyses may be made with respect to a video stream associated with the analyzed audio.
[0018] Metrics utilized in step 110 of FIG. 1 may also include controller input. For example, a metric may be measure with respect to latency between the controller input and execution of an event responsive to the controller input. Controller input may be generally by a manually manipulated interface device. Controller input may also be artificially generated such that signals representative or real-world interface are generated for testing but actual manipulation of a tangible input device does not occur. In the case of the former, controller input may be generated by visual tracking, audio tracking, or displacement of an object in three-dimensional space. Representative signals of such input may also be artificially generated.
[0019] Quality of service metrics may also include a required number of cycles to execute a portion of a software application corresponding to the software title. Quality of service may also be related to communication networks. For example, the quality of service may be related to determinations made with respect to bit rate and network delay. With respect to network delay, the delay analysis may be inclusive of a processing delay, queuing delay, transmission delay, or propagation delay. Network quality of service determinations may also be made with respect packet delay variation, packet dropping probability, and bit error rate.
[0020] Means for testing these various metrics may take place utilizing techniques, equipment, or other methodologies that are known to those of skill in the art. These various means may be incorporated into a system for quality of service assurance like that illustrated and described in FIG. 2 . Testing may also take place utilizing various facilities or analysis centers with the collective output being aggregated and analyzed at another locale. Testing may be automated and take place through a computing device. Testing may also be manual and relate to human perception. Testing may further weight and holistically consider the results of the two-both automated and manual testing. Acts related to analysis and reporting may likewise be automated and/or manual.
[0021] Testing, measurement, and other associated activities take place in step 120 as illustrated in FIG. 1 with respect, specifically, to a first platform. Similar (or identical testing) takes place in step 130 with respect to a second platform as illustrated in FIG. 1 . The second platform (as involved in measurement step 130 ) has different system architecture than that of the first platform (measured in step 120 ). The differences may apply to the platform as a whole (e.g., overall system design) or with respect to particular elements of the system (e.g., graphics processors, central processing units, or sound processing units). For example, while the PlayStation®3 from Sony Computer Entertainment Inc. and Microsoft® X-Box are both gaming platforms, the design of the PlayStation® differs from that of the X-Box. This difference in system architecture and components related to the same, in part, explains the overall superiority of the former versus the latter.
[0022] The nature of these differences may vary with respect to a particular metric or metrics. For example, the measured metric may not be affected by the system architecture of the second platform with respect to the measured metric on the first platform. Alternatively, the measured metric may be adversely affected by the system architecture of the second platform with respect to the measured metric on the first platform. The measured metric may also be positively affected by the system architecture of the second platform with respect to the measured metric of the first platform. The metric as measured on the first platform may not be the same and may fail to exceed the metric as measured on the second platform. The metric as measured on the first platform may be the same or exceeds the metric as measured on the second platform.
[0023] In step 140 of FIG. 1 , responsive action takes place. This responsive action may be based on results of the measurement of the metric on the first platform versus results of the measurement of the metric on the second platform. The responsive action may be a financial transaction related to development of the software title for the first platform. The financial transaction may be a payment conditioned upon the software title being the same or exceeding the metric as measured on the second platform. The responsive action may be a business incentive related to development of the software title for the first platform. The business incentive may be termination of a contract for future development of a software title for the first platform. The business incentive may be acceptance of a contract for future development of a software title for the first platform. The business incentive may be an exclusivity agreement for future development of a software title for the first platform. The financial transaction may be a forfeiture of funds previously paid to a software developer for development of the software title. The financial transaction may be a monetary penalty imposed against a software developer for failure to meet a standard of quality as established by a manufacturer of the first platform, the standard of quality corresponding to the metric. The monetary penalty may correspond to a degree of which the standard of quality failed to correspond to the metric.
[0024] FIG. 2 illustrates an exemplary system 200 for ensuring quality of a software title developed for multiple platforms. The system 200 of FIG. 2 includes a controller input or script generator 210 , differing system platforms 220 a and 220 b , software title 230 a and 230 b as authored or ported for each of the aforementioned platforms ( 220 a and 220 b ). System 200 further includes testing or analysis equipment 250 , which may include automated software analysis.
[0025] Through system 200 , the quality of a software title implemented on multiple platforms may be ensured. A first platform 220 a and a second platform 220 b have differing system architectures. A controller (as may be manipulated by a user) or script generator 210 (as may be found in a computing device) generates input recognized by the software title on the first platform 220 a and second platform 220 b . A software module (for example) at analysis equipment 250 measures a metric associated with the software title on both the first and second platform. Responsive action may be taken based on results generated from the measurement of the metric on the first platform versus the second platform.
[0026] The measured metric may not be affected by the system architecture of the second platform with respect to the measured metric on the first platform. The measured metric may be adversely affected by the system architecture of the second platform with respect to the measured metric on the first platform. The measured metric may be positively affected by the system architecture of the second platform with respect to the measured metric of the first platform. The first platform and the second platform may be emulated hardware environments or actual physical hardware components.
[0027] Controller input or script generator 210 may generate signal input corresponding to particular actions in a game. These actions may relate to effectuating a particular video or audio sequence (e.g., causing action in a game such that a particular scene is displayed) or be related solely to controller input to the extent that controller response is the testing metric (e.g., reaction to three-dimensional displacement of the controller in space). Input may be actual input generated by a controller as may occur through a person or automated piece of equipment causing manipulation of the control and/or actuation of certain button. The input may be scripted such that signals representative of actual manipulation of the control are generated notwithstanding the fact that the control itself has not been manipulated and may not even be presented. Input signals and/or scripts may be unique to a particular platform or may be generic. The controller/script generator 210 need not produce identical input (i.e., syntax) recognizable to both systems but input that corresponds to an identical or similar action in response to control manipulation (i.e., semantics).
[0028] Platforms 220 a and 220 b are game play or computing platforms with differing system architectures. Differences may encompass the system as a whole or be specific as to certain components such as a graphics processor or central processing unit. An example of differing platforms includes the PlayStation® 3 from Sony Computer Entertainment Inc. ( 220 a ) and the X-Box from Microsoft® Corporation ( 220 b ). The platforms may be an emulated hardware environment such that the actual gaming consoles are not present in the system. Instead, the platforms may be simulated through software and other drivers.
[0029] Software titles 230 a and 230 b are the games or other software applications that may be individually authored for each system or designed with a focus for one system and then ported to another system, which may include lack of functionality. In FIG. 2 , the software title is Madden Football 2009. It should be noted that the exact same disc or computer readable storage medium is not used on both platforms as the disc would likely be non-functional. Reference to the ‘same’ software title is a game or other software application that is then played or executed on each system through its own system-specific computer readable medium or software coding/authoring.
[0030] Game output 240 is then taken from each system for testing. In FIG. 2 , game output 240 is video output, which may be analyzed for one or more of the characteristics addressed in the context of FIG. 1 above. Testing equipment 250 then analyzes the output 240 from each system. Testing equipment may be platform specific but otherwise balanced with respect to a testing metric (i.e., the analysis equipment has been calibrated such that a certain quality of output on one platform has an equivalent quality on a competing platform). Analysis equipment 250 may be automated in the form of software such as a video analyzer in FIG. 2 . Analysis equipment may also involve any number of hardware components or other testing elements.
[0031] In some embodiments of the present invention, analysis may take place using human observation. In such an embodiment, a human being may provide feedback as to which video selection ‘looks better’ from the two tested platforms. Similarly with respect to audio output and what ‘sounds better.’ A human user may also be used to test platform reaction to control input such that the use may communication how well a controller responds with respect to corresponding in-game activity. The user performing the analysis may be the same user providing the input in certain embodiments. Analysis may involve a combination of human observation and automated feedback/analysis.
[0032] Analysis output 260 , which is frames dropped in FIG. 2 , is then output after being passed through the testing and analysis equipment 250 . Testing results may be automated and reduced to report form. Testing results (analysis output 260 ) may also be human feedback. An entity ( 270 ) then produces a report, which may be used to take responsive action to the testing results. Various types of responsive action have been discussed in the context of FIG. 1 .
[0033] FIG. 3 illustrates an exemplary method 300 for ensuring compliance with a contractual obligation related to quality of service in software development for a first platform. In step 310 , a contractual obligation is negotiated between a software developer and a platform provider. For example, Electronic Arts (a software developer) may negotiate with Sony Computer Entertainment Inc. (a platform provider) as to providing a particular software application (e.g., a video game) for operation on the PlayStation® 3 gaming console (i.e., the platform). Negotiations need not take place face-to-face nor need they take place directly through an authorized representative of either entity. Various intermediate proxies and negotiating techniques may be utilized with respect to formulating and executing a contractual agreement. The contract may encompass additional particularities of software development (e.g., deliverable time tables, marketing and promotion, and remuneration). The agreement may be specific to a particular software title, family of titles, or genre or catalog of applications and games to be provided for the platform.
[0034] Notwithstanding the negotiation of the agreement, the software developer may be permitted to enter into similar agreements with other platform providers. The software developer, in some instances, may have already entered into an agreement with another platform provider to provide the same game title. The other platform providers may offer a platform that has a system architecture that is distinct versus that of the party negotiating the current agreement. In some instances, these other platform providers may be direct competitors of the platform provider presently negotiating the contract. In that regard, the contract may not encompass exclusivity as to a particular platform. Some contracts may, however, provide for an initial period of exclusivity that expires after some period of time once the title has been released for purchase.
[0035] As a part of the negotiations, a quality of service metric is identified in step 320 of FIG. 3 . This quality of service metric may be inclusive of any one or more of the metrics identified above. The identification of this metric and means for assuring compliance with the same may occur through various contractual drafting techniques as are known to those of skill in the art. The contract may include a provision that prohibits the quality of service for the identified metric from being less on the present platform than any other platform for which a contract has been or might be negotiated. In this way, the platform provider ensures that no other platform provider or competitor may offer the software title such that it performs better for any given metric or metrics on their particular platform. The metric may also be presented in the negative such that the measurement of the quality of service metric does not reveal a lesser performance on the platform presently being negotiated versus measurement of that same metric on any other platform.
[0036] In step 330 of FIG. 3 , the contract is executed and the software provider and platform provider ‘enter into’ the contract for development of the software title on the platform of the platform provider. Following execution of the contract, periodic testing may take place by either the software provider or the platform provider to ensure compliance with the quality of service metric obligations. Testing may take place by the software provider, the platform provider, or an independent third-party. Depending on the results of the testing, certain responsive action may take place, which may be set forth in the terms of the contact. Examples of responsive action are addressed in the contact of FIG. 1 . Responsive action may be related to the failure of the software provider to comply with the quality of service metric (e.g., another platform exhibits better performance for a given metric) or for exceeding the requirements of the metric. Responsive action, in this regard, may be retributive or a reward.
[0037] Certain of the aforementioned methodologies may be executed by a processor at a computing device. The computing device may execute these methodologies through the processing of a computer program embodied in a computer-readable storage medium. The storage medium is inclusive of media such as a CD, memory, floppy disk, flash memory, and hard drive.
[0038] While the present invention has been described in connection with a series of embodiments, these descriptions are not intended to limit the scope of the invention to the particular forms set forth herein. To the contrary, the present descriptions are intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims and otherwise appreciated by one of ordinary skill in the art.
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Assurance of quality with respect to of a software application across different operating platforms with different system architectures is provided. Methods for determining and assuring said quality as well as a system for the same is disclosed. A method for ensuring compliance with a contractual obligation related to quality of service in software is also disclosed.
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BACKGROUND OF THE INVENTION
Thixotropic compositions are useful as coatings in many applications including the automotive industry where they are used as undercoating materials and interior cavity protective films.
A composition having thixotropic properties has a reduced viscosity under high shear conditions and a higher viscosity under low shear conditions. These properties are particularly useful in applications where it is desired to apply a normally viscous composition to surfaces using spraying equipment that, after spraying, results in adherence of the compositions to the surfaces. In the particular application of an undercoating material, in order to be effective as an undercoating material, the compositions should have spray properties enabling uniform spraying and atomization properties. In addition, other physical properties should provide appropriate properties of adhesion, cure time, sag (resistance to flow on vertical surfaces), heat-stability (sag at elevated temperature), film continuity as well as anti-corrosion and sound deadening properties.
Many coating compositions have been developed in the past and the market is well supplied with different products, many of which have unique properties and chemistries. As a result, there are a large class of compositions that provide some or many of the above properties.
From an economic or commercial perspective, there continues to be a need for thixotropic compositions that provide improvements in the above properties and that are economic to manufacture. That is, with the cost of raw materials and manufacturing processes affecting the cost to the consumer, there continues to be a need for protective coating compositions that remain competitive within the marketplace. In particular, there is a need for thixotropic compositions that are produced by a simplified and reliable process using readily available, economical and non-hazardous raw materials with simplified equipment and production times.
A review of the prior art indicates that in the past, many thixotropic compositions have been prepared by methodologies that result in various forms of calcium carbonate/calcium sulfonate mixtures having properties that impart corrosion resistance to metal surfaces. However, in many of these past processes, the use of other ingredients, such as promoters, have been required to achieve various chemical reactions, impart specific physical properties and/or to enable the creation of a stable colloidal suspension. Generally, surfactant materials (ie. oil soluble long-chain carboxylate salts and/or sulfonate salts) are required to make non-polar oil-like materials more compatible with polar inorganic salts (Ca(OH) 2 and CaCO 3 ) to enable the creation of a colloidal suspension of oils and the salt complexes.
Some of these past processes substitute all or part of the calcium sulfonate with calcium salts of various types of carboxylic acids. For example, U.S. Pat. No. 4,597,880 describes thixotropic compositions including short-chain water-soluble carboxylic acids that function as promoters to achieve needed chemical reactions and/or physical processes to enable calcium carbonate to be distributed as a colloidal suspension in oil-like carrier materials in a form which is sufficiently finely divided so as not to settle out.
Importantly, the advantages of eliminating promoter materials include:
a. The cost of using a material which has no functionality in the final product is eliminated; b. The promoter materials are generally low flash organic materials (eg. alcohols) which require plant equipment for containment, ventilation etc. for safety and environmental reasons; and, c. There is evidence that these promoters interfere with the subsequent stage of producing the thixotropic materials, which is transforming the colloidal suspension into a gelled material. As a result, several processes may be required to strip the promoter materials out before proceeding to the next stage.
Moreover, past thixotropic compositions all disclose the use of sulfonic acids having a minimum aliphatic carbon chain length of 12 carbon atoms that are less reactive and are more expensive.
Further still, past processes have been made complex through manufacturing processes requiring the formation of CaCO 3 “in situ” by reaction of excess Ca(OH) 2 with CO 2 gas in order to obtain the necessary finely divided, and completely dispersed calcium carbonate particles that enable a colloidal dispersion. Thus, there has been a need for a process utilizing the addition of solid CaCO 3 that provides the desired physical/chemical results as well as the economic advantages of utilizing a single-step mixing process as opposed to a multiple-step chemical process.
As an example, Canadian Patent 2,057,196 describes longer chain (C8-C24) carboxylic acids in combination with oil soluble sulfonic acids neutralized to calcium salts with excess calcium hydroxide. In this patent, a calcium carbonate complex is produced by reaction of excess calcium oxide (or calcium hydroxide) with carbon dioxide gas introduced to the reaction mixture. This process has been described as necessary to obtain the calcium carbonate in the appropriately finely divided crystalline form. Furthermore, in this process, an alcohol “reaction promoter” is also utilized to form an initial “oil soluble dispersing agent”.
Other prior art patents include U.S. Pat. No. 3,816,310 which discloses a method for preparing a rust inhibiting composition that contains oil soluble metal salts of sulfonic acids, carboxylic acids, and phosphorous sulfide treated olefins; U.S. Pat. No. 4,597,880 which discloses a one-step process for preparing a thixotropic calcium sulfonate complex containing calcium carbonate with calcium sulfonate being a dispersing agent; U.S. Pat. No. 5,407,471 which discloses a process for inhibiting the corrosion of metal by applying a coating containing an organic acid and at least one metal containing corrosion inhibitor; U.S. Pat. No. 4,161,566 which discloses the formation of an aqueous dispersion composition of irreversibly formed films by reacting a carboxylic acid with an overbased salt; U.S. Pat. No. 4,629,753 which discloses a water dispersed rust inhibiting composition comprising a film forming organic polymer and a non-Newtonian dispersion system comprising colloidal particles, a dispersing medium and a hydrophobic organic compound; U.S. Pat. No. 4,479,981 which discloses a thixotropic water reducible corrosion resistant coating containing carboxylic acid, an overbased sulfonate and an alcoholic coupling solvent such as propyl glycol ether and water.
SUMMARY OF THE INVENTION
In accordance with the invention, there is provided a method of preparing a thixotropic composition comprising the steps of:
a) mixing a major proportion of a carboxylic acid with a minor proportion of a sulfonic acid and a stoichiometrically equivalent amount of calcium hydroxide relative to the carboxylic acid and sulfonic acid with an oil diluent and heating the mixture to form a salt/diluent complex and reaction water; b) removing the reaction water and cooling the salt/diluent complex; c) adding additional oil diluent to reduce the viscosity of the salt/diluent complex; d) adding calcium carbonate to form an overbased complex; and e) cooling the overbased complex and adding water to the mixture to produce a thixotropic composition.
In various embodiments of the method the carboxylic acid is a C14-C20 aliphatic carboxylic acid, the carboxylic acid is a tall oil fatty acid, the sulfonic acid is a C10-C18 aliphatic sulfonic acid, and/or the sulfonic acid is an alkyl aryl sulfonic acid wherein the alkyl group is C8-C14.
In other embodiments, the sulfonic acid is 5-15% wt % of the total acid content and/or the oil diluent in step a) is 10-35 wt % of the carboxylic acid and sulfonic acid.
In another embodiment, the method further comprises the step of blending the thixotropic compound with asphalt or waxes.
The invention also provides thixotropic compositions prepared in accordance with the method including a thixotropic composition comprising 30-56 wt % diluent, 10-30 wt % carboxylic acids, 1-6 wt % sulfonic acids, 1-6 wt % calcium hydroxide, 5-30 wt % calcium carbonate, 5-20 wt % water and, 0-2 wt % sodium hydroxide. The invention also specifically provides a thixotropic composition comprising 36 wt % diluent, 26 wt % carboxylic acids, 3 wt % sulfonic acids, 4 wt % calcium hydroxide, 19 wt % calcium carbonate and, 12 wt % water as well as a thixotropic composition wherein the carboxylic acid is 26 wt % tall oil fatty acid and the sulfonic acid is 3 wt % dodecyl benzene sulfonic acid.
DETAILED DESCRIPTION OF THE INVENTION
Thixotropic compositions and methods of making these compositions are herein described.
The thixotropic compositions in accordance with the invention comprise complexes formed by calcium salts of long chain carboxylic acids (fatty acids or other long chain fatty acids) and relatively shorter-chain sulfonic acids together with oil diluent to disperse calcium carbonate within a colloidal suspension. The calcium salts are formed from a mixture of the long chain fatty acids (for example, C14-C20), the shorter-chain sulfonic acids (for example, C8-C14 alkyl aryl sulfonic acid) and calcium hydroxide. The resulting compositions are particularly useful as anti-corrosive compositions for protecting surfaces from rust and other damage.
In accordance with the invention, a blend of a major proportion of carboxylic acids and a minor proportion of sulfonic acids (preferably alkylbenzene sulfonic acids) and oil diluent are mixed together in a reaction vessel. A stoichiometric equivalent amount of lime (calcium hydroxide), relative to the total number of moles of the acids, is added to the mixture to neutralize the acids and to form a salt complex of the carboxylic acid/sulfonic acid in an exothermic reaction with water as a product of the reaction. During the reaction, the water boils off to produce a viscous mixture.
The mixture is then cooled and diluted with additional oil diluent to form a lower-viscosity mixture containing dispersed oil diluent.
Calcium carbonate is added to the mixture to combine with the salt complex to form an overbased complex wherein the calcium carbonate is either dispersed within the mixture as a fine dispersion or is solubilized within the mixture.
The mixture is further cooled and then mixed with a sufficient quantity of either water or dilute caustic soda (sodium hydroxide) to form a grease-like composition. If water is added in the final step, conversion to a semi-solid grease takes place slowly as the material cools to room temperature, allowing the material to be pumped easily from the reaction vessel to a storage container where solidification occurs. If caustic soda is added, conversion to semi-solid grease takes place rapidly. Additional caustic soda in solution may also be added after crystallization to provide improved heat stability to subsequent formulated products.
It is preferred that the compositions are prepared with 5-15% sulfonic acid to 85-95% carboxylic acid by weight.
Sulfonic Acids
Sulfonic Acids can be selected from sulfonic acids having an average aliphatic chain length of 10 or more or linear alkyl benzene sulfonic acids with aliphatic carbon chain lengths of 8-14 carbon atoms. A preferred sulfonic acid is dodecyl benzene sulfonic acid such as BIOSOFT S-100 (Stepan Chemical, Northfield Ill.). It is also preferred that greater than 90% of the sulfonic acids have chain lengths in the range of C8-C12.
Carboxylic Acids
Carboxylic acids can be selected from carboxylic acids having an aliphatic chain length of 14 carbon atoms or greater. “Tall oil” fatty acids are particularly effective such as TOFA 4 (18-Carbon-Mono- and Diunsaturated fatty acids) from Hercules Chemical (Mississauga, Ontario).
Lime
Fine powder lime such as CODEX HYDRATED LIME (Mississippi Lime Company) is preferred. In particular, fine lime powder having a particle size distribution of 99.9% smaller than 100 mesh, 99.0% smaller than 200 mesh and 96.5% smaller than 325 mesh is preferred.
Oil Diluents
The oil diluents can be selected from any aliphatic or aromatic hydrocarbon solvent or oil that is inert with respect to the overall reaction and can be selected from those as known to those skilled in the art.
In particular, mineral oil and mineral spirits are effective in the process and compositions.
Calcium Carbonate
Fine-ground calcium carbonate such as 3HX calcium carbonate from Imasco Minerals Inc. is preferred.
Water and/or Caustic Soda Addition
As noted above, in the final step of the process, a quantity of either water or dilute sodium hydroxide is added to the mixture under agitation while cooling is taking place and preferably between approximately 20-65° C. If sodium hydroxide is used, the sodium hydroxide concentration in water is approximately 5-15% (by weight) and preferably 12% (by weight). Addition of the dilute caustic soda solution instead of pure water results in a more rapid crystallization and thickening to a grease. Treatment of the thickened composition with additional caustic soda after crystallization (thickening) is preferred to optimize the heat stability properties of the composition at temperatures above 45° C.
EXAMPLES
Example 1
18.4 liters of mineral spirits diluent were mixed with 50.5 kg of tall oil fatty acids and 5.8 kg of C10 alkyl benzene sulfonic acid in a 200 liter stainless steel mixing vessel equipped with a water jacket for heating and cooling and a ½ hp mixer having 37 inch propeller-type agitator blades. The mixture was heated to 80-100° C. with moderate agitation. 7.25 kg of fine calcium hydroxide powder (96%+smaller than 325 mesh) was sifted into the mixture with agitation causing an exothermic reaction as the calcium hydroxide reacted with the acids resulting in a viscous, dark brown homogenous fluid. Water formed by the reaction was allowed to boil off.
When the boiling ceased, the mixture was allowed to cool while maintaining agitation and a further 71.1 liters of mineral spirits diluent was added slowly to the mixture.
When the diluent addition was completed and the mixture had cooled to 70° C., fine particle size calcium carbonate was slowly sifted in the mixture under agitation to form a tan colored, moderately viscous fluid.
Mixing was maintained for approximately 60 minutes as the mixture continued cooling to 62° C. No accelerated cooling was done.
At 62° C., 22.9 liters of water was added and mixing continued for a further 30 minutes whereupon the mixture was pumped to a storage vessel to cool to room temperature.
When cooled and solidified, the final material was a brown, firm grease-type material.
Example 2
Example 1 was repeated with the difference that the mixture was cooled further before water addition. In this example, during cooling and at approximately 52° C., 22.9 liters of cold water (at ambient temperature) were added. Mixing was continued for a further 15 minutes and the mixture was then pumped to a storage vessel and allowed to cool to room temperature.
When cooled and solidified, the final material was a brown, soft, grease-type material.
Example 3
356 g of tall oil fatty acid and 40 g of CIO alkyl benzene sulfonic acid and 100 g of mineral spirits diluent were mixed in a 2 liter stainless steel flask. The flask was heated to 90° C. in a hot water bath.
51 g of calcium hydroxide were slowly added with agitation and the temperature of the mixture rose to 100° C. with evolution of water vapor. Mixing was continued for 15 minutes until the water boiling ceased. The mixture was a viscous, dark brown homogenous liquid.
386 g of mineral spirits diluent was added to the mixture with agitation and the vessel was placed in a cold-water bath to cool. At 42° C., 255 g of calcium carbonate was added while cooling and mixing was continued for 30 minutes. The temperature after cooling was 26° C.
5.4 g of caustic beads were dissolved in 161 g of water and added to the mixture with mixing. Mixing continued for 20 minutes and the mixture was removed from the water bath to complete cooling to room temperature.
After 48 hours, the product was very soft, deformable light brown grease.
Product Performance
Additional compounding of the products into different protective coating products tested the performance of the grease products. These included asphaltic-based coating products that are useful for underbody coatings and wax-based coating products that are useful for interior cavity rust protection.
Asphaltic-Based Coating Products
Grease prepared in accordance with example 2 was mixed with asphalt, an inorganic mineral drying agent/filler, a solvent and caustic soda solution in proportions of standard undercoating formulations to produce an asphaltic product.
The asphaltic product was subjected to performance tests including sag tests and spray tests described as follows:
Sag Test
⅛″ (3.2 mm) of the asphaltic product was deposited onto a steel plate. The sample plate was suspended vertically and heated via a heat lamp. The temperature of the plate was recorded to observe the temperature at which the product began to sag or run down the metal surface. Samples exhibited no sag behavior up to at least 70° C.
Spray Test
The asphaltic product was sprayed through commercial spray equipment utilizing a standard equipment setup (nozzle tip size, pump pressure, product temperature). Qualitative evaluations were made based on spray characteristics such as ease of atomization, and amount of overspray or misting. This provided a practical means of measuring the amount of thixotropy exhibited by the various grease products.
Wax-Based Coating Product
Grease prepared in accordance with example 2 was mixed with a microcrystalline wax, a diluent and a caustic soda solution in proportions of standard interior cavity formulations to produce a wax-based product.
Sag Test
A sag test as above was performed with similar results.
Spray Test
Spray tests using commercial rust proofing spray equipment were conducted by spraying the wax-based product on flat metal panels. Qualitative evaluations of film continuity and spray characteristics were acceptable.
Corrosion Resistance Test
Both asphaltic- and wax-based samples were also evaluated for corrosion resistance by spray coating ½ the surface of a 3″×5″ cold rolled steel plates with each product. The plates were then sprayed with 5% salt solution at periodic intervals and the development of rust observed on the coated and uncoated portions of the plates. Other samples were submitted to an independent laboratory for testing according to the ASTM B-117 salt fog test. The asphaltic- and wax-based products were compared to materials from competitive products treated in the same way. The results indicated that the products provided acceptable properties to the comparable, competitive products.
Discussion
The invention shows that the use of relatively shorter chain sulfonic acids together with longer chain carboxylic acids without the use of promoters enables the synthesis of thixotropic compositions having suitable end use properties. While the shorter chain sulfonic acid does not provide good suspension properties by itself, it does provide good reactivity, which in combination with the longer chain carboxylic acids, makes for stable colloidal suspensions, and when gelled gives excellent thixotropic properties.
In addition, the invention demonstrates that the production of thixotropic compositions having improved temperature stability is achieved with the addition of a caustic soda solution after the gelling or crystallization step.
Further, the methodology and compositions prepared in accordance with the invention, provide economic and technical advantages over past processes particularly as carboxylic acids are less expensive than sulfonic acids and further permits the use of types of sulfonic acids that are more widely available and more economic than those used in previous processes.
In addition, it has been discovered that the cooling rate and temperature at which the water is added are variables that can be used to provide control of the final consistency of the thickened composition, ranging from soft to firm grease. More specifically, conditions that promote rapid crystallization of calcium carbonate give rise to soft greases. Such conditions include either: a) a lower mix temperature when water comes into intimate contact with the mixture; b) longer mixing times after water addition; and/or, c) a more vigorous mixing of water into the mixture.
For example, for the creation of soft grease, room temperature calcium carbonate was added to the mixture at approximately 70° C. (this resulted in a mixture temperature of approximately 60-65° C.). The mixture was cooled to approximately 56° C. with a water jacket and room temperature water was added and mixed for approximately 1 hour to give a final mixture temperature of 40-46° C. before pumping to storage. After 24 hours, the mixture was soft grease.
In comparison, firm grease was created by adding room temperature water to the mixture (containing calcium carbonate) at a higher temperature (60-65° C.) followed by 30 minutes of mixing prior to pumping to storage. After 24 hours, the mixture was firm grease.
Very soft grease was prepared in accordance with the process for preparing the soft and firm greases but with cooling of the mixture (containing calcium carbonate) to a lower temperature of 45° C. Addition of room temperature water at 40-45° C. and a shorter mixing time (approximately 15 minutes) resulted in a final mixture temperature of approximately 33° C. prior to pumping to storage. After 24 hours, the mixture was very soft grease.
While the above descriptions generally refer to soft, firm and very soft greases and the temperatures of water addition that promote the formation of such greases, it is understood that a range of consistencies of greases can be created within the disclosed temperature ranges and in accordance with the invention.
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The invention relates to thixotropic compositions and methods of manufacture. The compositions are prepared from fatty acids and sulfonic acids mixed with a stoichiometrically equivalent amount of calcium hydroxide. Oils, calcium carbonate and water are also added to create viscous, grease-like materials that are particularly useful for undercoating applications as well as corrosion inhibiting film coatings.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention involves coating a fiber mat, with the coating comprising mineral pigment and organic binders. These coated mats have many uses, but are especially useful as a facing on a gypsum wallboard for exterior application and on which stucco is applied.
[0003] 2. Description of the Related Art
[0004] Fibrous non-woven mats are often formed into a wet mat from an aqueous dispersion of fibers such as glass and/or synthetic organic fibers which can include other fibers such as cellulose fibers, ceramic fibers, etc. and can also include particles of inorganic material and/or plastics. Usually a solution of urea formaldehyde resin, usually modified with a thermoplastic polymer, or one of many other known resin binders is applied to the wet non-woven web of fibers and then, after removing excess binder and water, the bindered web is dried and heated further to cure the urea formaldehyde resin or other resin binder to form a non-woven mat product. A typical process is disclosed in U.S. Pat. Nos. 6,723,670, 4,112,174 and 3,766,003, the disclosures of which are hereby incorporated herein by reference.
[0005] Wallboard formed of a gypsum core sandwiched between facing layers is used in the construction of virtually every modern building. In its various forms, the material is employed as a surface for walls and ceilings and the like, both interior and exterior. It is relatively easy and inexpensive to install, finish, and maintain, and in suitable forms, is relatively fire resistant.
[0006] Although paper-faced wallboard is most commonly used for finishing interior walls and ceilings, other forms with different kinds of facings have superior properties that are essential for other uses. One known facing material is non-woven fiberglass mat.
[0007] U.S. Pat. No. 4,647,496 discloses an exterior insulation system including a fibrous mat-faced gypsum board having a set gypsum core that is water-resistant. The fibrous mat is preferably sufficiently porous for the water in the gypsum slurry to evaporate during the production drying operation as the gypsum sets. The mat comprises fibrous material that can be either mineral-type or a synthetic resin. One preferred mat comprises non-woven fiberglass fibers, randomly oriented and secured together with a modified or plasticized urea formaldehyde resin binder, and sold as DURA-GLASS® 7502 by the Manville Building Materials Corporation.
[0008] Notwithstanding the advances in the field of gypsum boards and related articles, there remains a need for a readily and inexpensively produced mat-faced gypsum board having one or more of a smoother surface, and better processing characteristics.
SUMMARY OF THE INVENTION
[0009] Provided herewith is a non-woven fiber mat having a coating comprised of a mineral pigment and an organic binder. The coating penetrates the fiber mat so as to control porosity of the mat and impart a smooth surface to the mat. The mineral pigment is chosen to have a size to allow for good packing and to allow for penetration of the fiber mat, while also permitting sufficient porosity to provide air/vapor permeability. The mineral pigment in the coating also is of sufficient small size to impart, together with the organic binder, a smooth surface to the mat.
[0010] Preferably, the mineral pigment is of a size (diameter) less than 6μ, and more preferably around 3μ.
[0011] The non-woven fiber mat is preferably a glass fiber mat, employing an organic binder. Preferably, the organic binder is a polymeric latex or mixture thereof.
[0012] The non-woven fiber mats of the present invention have many different applications, but primarily in laminates comprising a base layer such as a gypsum wallboard. Laminates involving other baseboards such as insulating boards, plywood, foamed boards are also contemplated. However, use in preparing a faced insulating gypsum board is a preferred application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] It is known to make non-woven mats from glass fibers and to use these mats as substrates in the manufacture of a large number of roofing and other products. Any known method of making non-woven glass fiber mats can be used, such as the conventional wet laid processes described in U.S. Pat. Nos. 4,129,674; 4,112,174; 4,681,802; 4,810,576 and 5,484,653, the disclosures of each being hereby incorporated herein by reference. In these processes a slurry of glass fiber is made by adding glass fiber to typical white water in a pulper to disperse the fiber in the white water and to form a slurry having a fiber concentration of about 0.2-1.0 wt. %, metering the slurry into a flow of white water to dilute the fiber concentration to 0.1 wt. % or less, and continuously depositing this mixture onto a moving screen forming wire to dewater and form a wet non-woven fibrous mat. This wet non-woven mat is then conveyed through a binder application where an aqueous resinous binder is applied in excess, the surplus being removed by suction. The wet, bindered mat is then dried and the binder cured to form a non-woven mat product.
[0014] The method of U.S. Pat. No. 4,129,674, employs a wet-laid, inclined wire screen mat-forming machine. Generally stated, the method comprises forming a slurry, preferably a water slurry, containing the requisite fibers. The solids content of such a slurry may be very low, such as approximately 0.2%. The slurry is intensely mechanically agitated to disperse the fibers uniformly therein and then dispensed onto a moving screen. A vacuum is applied to remove a substantial part of the water, which is preferably recycled, and thereby form a web of the fibers. After application of a binder, the web is heated to evaporate any remaining water and cure the binder, thus forming the bonded mat. Preferably, the mat-forming process is carried out in a continuous operation. The moving screen is provided as a continuous conveyor-like loop and is slightly upwardly inclined during the portion of its travel in which the fiber slurry is deposited thereon. Subsequently, a binder is applied and the mat heated to effect final drying and curing. After the vacuum step is completed, the web is optionally transferred to one or more additional downstream conveyor systems for binder application and passage through a heated oven for the final drying and curing operation. Machines suitable for carrying out such a web-forming process are available commercially and include devices manufactured under the tradenames Hydroformer™ by Voith-Sulzer of Appleton, WS, and Deltaformer™ by Valmet/Sandy Hill of Glens Falls, N.Y.
[0015] Preferably, the majority of the fibers in the non-woven mat are glass fibers, and most preferably all the fibers are glass fibers. However, this invention is equally applicable to ceramic, natural, wood pulp like, manmade cellulousic fibers and polymeric fibers, and to non-woven webs made from mixtures of any combination of these types of fibers. While the majority of the fibers are glass fibers in the preferred embodiment, all or any portion of non-glass fibers can also be included, such as manmade or natural organic fibers like nylon, polyester, polyethylene, polypropylene, cellulose or cellulose derivatives, etc.
[0016] The fibers used in the non-woven mat should be at least 0.25 inch long or longer, more preferably at least one half inch or three quarters inch long and most preferably at least about one inch long, but mixtures of fibers of different lengths and/or fiber diameters can be used as is known. It is preferred that these fibers be coated with a silane containing size composition as is well known in the industry. A preferred continuous glass fiber for fibrous web is at least one member selected from the group consisting of E, C, and T type and sodium borosilicate glasses, and mixtures thereof. As is known in the glass art, C glass typically has a soda-lime-borosilicate composition that provides it with enhanced chemical stability in corrosive environments, and T glass usually has a magnesium aluminosilicate composition and especially high tensile strength in filament form. The present mat is preferably composed of E glass, which is also known as electrical glass and typically has a calcium aluminoborosilicate composition and a maximum alkali content of 2.0%. E glass fiber is commonly used to reinforce various articles. The chopped fibers of the major portion can have varying lengths, but more commonly are substantially of similar length. E glass fiber has sufficiently high strength and other mechanical properties to produce acceptable mats and is relatively low in cost and widely available. Most preferred is E glass having an average fiber diameter of about 11.+−.1.5 μm and a length ranging from about 6 to 12 mm.
[0017] The aforementioned glass fibers are bound together with any known water resistant resinous binder. Suitable binders include urea formaldehyde; conventional modified urea formaldehyde; acrylic resins; melamine resins, preferably having a high nitrogen resins such as those disclosed by U.S. Pat. No. 5,840,413; homopolymers or copolymers of polyacrylic acid having a molecular weight of less than 10,000, preferably less than 3,000; crosslinking acrylic copolymer having a glass transition temperature (GTT) of at least about 25° C., crosslinked vinyl chloride acrylate copolymers having a GTT preferably no higher than about 113° C.; and other known flame and water resistant conventional mat binders. It is typically found that a lower GTT promotes better softness and smoothness of the mat surface, but tensile strength is improved with a higher GTT. Binder systems having a GTT ranging from about 15 to 45° C. are thus preferred. Aqueous modified and plasticized urea formaldehyde resin binders may be used and have low cost and acceptably high performance.
[0018] A preferred binder for the present mat comprises an acrylate copolymer binder latex with a GTT of about 25° C. available from Noveon, Inc. of Cleveland, Ohio, under the tradename Hycar™ 26138. As delivered, this acrylate copolymer latex has a solids content of about 50 weight percent solids, but it is preferred to dilute the concentration with water to about 25 wt. percent solids before using it. Preferably up to about 10 weight percent of a crosslinker such as melamine formaldehyde is added to the acrylate; and more preferably about 2-5 weight percent crosslinker is added. Advantageously, mat bound with the acrylate copolymer latex is smoother and the mat thinner for equivalent weight and properties than with other known binders. In addition, expensive fluorochemical emulsions needed in certain prior art binders are not required.
[0019] The amount of acrylate copolymer latex binder (and any optional cross-linker) left in the wet mat during manufacture can be determined by a loss on ignition (LOI) test, the result thereof being specified as a percentage of the dry weight of the finished mat. Preferably, the amount of binder in the final mat, based on its dry weight, ranges from about 15 to 35 wt. percent, with about 20-30 wt. percent being more preferred, and 25.+−.2.5 wt. percent being most preferred. The upper limit is dictated by process constraints and cost, while the minimum is required for adequate tensile strength.
[0020] The aqueous binder solution is preferably applied using a curtain coater or a dip and squeeze applicator. Normally, the mat is subjected to temperatures of about 120-330° C. for periods usually not exceeding 1 or 2 minutes, and frequently less than 40 seconds, for the drying and curing operations. Alternative mat forming methods useful in forming mat for the present invention include the use of well-known cylinder forming and “dry laying.”
[0021] Optionally the fibrous mats of the present invention further contain fillers, pigments, or other inert or active ingredients either throughout the mat or concentrated on a surface. For example, the mat can contain an effective amount of fine particles of limestone, glass, clay, coloring pigments, biocide, fungicide, intumescent material, or mixtures thereof. Such additives may be added for known structural, functional, or aesthetic qualities imparted thereby. These qualities include coloration, modification of the structure or texture of the surface, resistance to mold or fungus formation, and fire resistance. Preferably, flame retardants sufficient to provide flame resistance, e.g. according to NFPA Method 701 of the National Fire Protection Association or ASTM Standard E84, Class 1, by the American Society for the Testing of Materials, are added. Biocide is preferably added to the mat and/or gypsum slurry to resist fungal growth, its effectiveness being measurable in accordance with ASTM Standard D3273. The mats and gypsum layer of the present invention preferably have a very low cellulosic fiber content from which microbes could derive nutrition. More preferably any cellulosic fiber present in the mats or gypsum is only an impurity of other ingredients.
[0022] The coating composition employed for the non-woven fiber mat comprises mineral pigments along with an organic binder. The mineral pigments are such that the coating does penetrate the fiber mat and provides a unique combination of surface porosity and surface smoothness. Generally, the mineral pigments are of a size of less than 6μ, and more preferably less than 5μ, and most preferably about 3μ or less. The mineral pigment and binder penetrate either partially or fully through the mat, with the pigment being selected so as to provide a controlled porosity that permits evaporation of water vapor, but still acts as a water barrier and does not allow water to pass through the mat. Most preferred mineral pigments are pigments such as calcium carbonate and talc.
[0023] In a most preferred embodiment, the mineral pigments are calcium carbonate. Calcium carbonate comes in several sizes. Calcium carbonate is also commercially available, for instance it is available under the trademark Atomite™. The size of the mineral pigments is generally such as to permit air permeability of the fiber mat, but also impart a smooth surface to the mat. A particle size of about 3 micron is preferred. Calcium carbonate at such a particle size has unique packing characteristics in a dried coating layer on top of a non-woven fiber web such as a fiberglass web. Using calcium carbonate at such a size provides controlled air permeability at a much lower coating weight than when larger particle sizes are employed.
[0024] The coating weight is generally measured as grams per square feet, and air permeability can be measured using many different known methods, e.g., it can be measured in seconds of a known amount of air mass to pass through the web, as measured by instruments such as the “Gurley Densonater”. Generally, the air permeability of the coated mats of the present invention is less than 60 seconds and more preferably less than 50 seconds, and most preferably less than 40 seconds and in the range of from about 20-40 seconds. The air permeability of a mat can also be conventionally measured by the air flow between reservoirs separated by the mat using a test called the Frazier test, which is further described by ASTM Standard Method D737, with the results ordinarily being given in units of cubic feet per minute per square foot (cfm/ft 2 ). The test is usually carried out at a differential pressure of about 0.5 inches of water. In preferred embodiments, the permeability of the present mat, as measured by the Frazier method, is at least about 250, and more preferably, at least about 300 cfm/ft 2 .
[0025] The ability of the present invention to control the air permeability without employing a very heavy coating has great cost advantage. A controlled permeability is needed for downstream converting processes, particularly when the non-woven web is used as a facer for a gypsum board. A highly permeable facer would lead to bleed through of underlying material such as gypsum in a wallboard converting process, whereas very low permeability would lead to moisture being trapped in the downstream converting process of a gypsum board. The present invention permits one to control the permeability by selecting the particular mineral pigment, its size and its packing characteristics, while also imparting a very smooth surface to the non-woven mat.
[0026] The coating composition further comprises an organic binder, and is preferably a blend of thermoplastic latexes as the organic binder. Such thermoplastic latexes are well known, as discussed above. It is found that a blend of such latexes provides the best results and are therefore preferred. The use of an aqueous thermoset resin such as an acrylic or epoxy resin is also preferred. Other examples of suitable organic binders includes non-acrylic based (e.g., branched vinyl ester) polymers, or a mixture of an aqueous thermoplastic dispersion and thermoset resin. It is also possible to mix an acrylic monomer or other suitable monomer with an initiator and the mineral pigment to create in situ the organic binder.
[0027] The coating composition can also include additional, conventional additives such as surfactants, rheology modifiers, oxidative stabilizers, colorants, biocides, etc.
[0028] In a preferred embodiment the fiber mats of the present invention comprise a non-woven web bonded together with a resinous binder and coated in accordance with the present invention, with the mat being used for one or both of the large faces of gypsum board. In such an application, the web preferably comprises chopped continuous glass fibers, of which preferably at least about 90 percent, more preferably at least about 95 percent, and most preferably at least about 97 percent have a fiber diameter of less than 30μ, and more preferably within a narrow range of about 11.±.1.5 μm. Although mixtures of different lengths of chopped strand fibers are contemplated and included within the scope of the invention, it is most preferred that a majority of the fibers have lengths greater than 2 mm, and more preferably lengths of 12.±.6 mm. The present web also includes a small fraction of fibers that are broken into two or more pieces and a very small fraction of small glass fibers and chips. The presence of such broken and chipped fibers in a chopped fiber product is well known in the fiber industry.
[0029] Chopped strand fibers are readily distinguishable from staple fibers by those skilled in the art. Staple fibers are usually made by processes such as rotary fiberization or flame attenuation of molten glass known in the fiber industry. They typically have a wider range of lengths and fiber diameters than chopped strand fibers. By way of contrast, it would have been anticipated that the smoothest mats would be obtained with a preponderance of fine fibers.
[0030] Even more importantly, the surface of boards made in accordance with the present invention has an improved “hand,” i.e., an improved subjective feel, and better accepts surface treatments because of its greater smoothness. Even after prior art boards are coated with substantial amounts of paint in multiple coats, the texture of the facing mat in many instances remains visible, making the surface aesthetically unpleasing for many applications. By way of contrast, the present boards may be finished to provide an aesthetic and functional surface with far less paint and the associated labor to prepare the surface and apply the paint or other desired finish, wallpaper or other coating, or the like.
[0031] It is preferred that the binder used for the present mats comprise an effective amount of a water repellant to limit the intrusion of gypsum slurry during board production. For example, vinyl acrylate latex copolymers may further incorporate stearylated melamine for improvement in water repellency, preferably at a level ranging from about 3 to 10 wt. %, and more preferably at about 6 wt. %. A suitable aqueous stearylated melamine emulsion is available from the Sequa Chemical Corporation, Chester, S.C., under the tradename SEQUAPEL™ 409. The stearylated melamine is in liquid form having a solids content of about 40 wt. percent and is mixed with a suitable copolymer latex and water to prepare binders for the mats. This material mixture has a pH of about 9, a viscosity of about 45 centipoises and is anionic. In addition, gypsum board incorporating mat with the preferred binder is more resistant to abrasion than conventional either fiber-faced or paper-faced boards.
[0032] Gypsum board in accordance with the present invention preferably is faced with a mat having a basis weight ranging from about 0.6 to 2.2 pounds per 100 square feet, more preferably ranging from about 0.9 to 2.2 lbs./100 sq. ft., and most preferably about 1.25.+−.0.2 lbs ./100 sq. ft. (about 29-110, 45-110, and 60.+−.10 g/m 2 , respectively). Preferably the binder content of the dried and cured mats ranges from about 10 to 35 wt. percent, more preferably from about 15 to 30 wt. percent, and most preferably from about 25.+−.3 wt. percent, based on the weight of the finished mat. The basis weight must be large enough to provide the mat with sufficient tensile strength for producing quality gypsum board. At the same time, the binder content must be limited for the mat to remain sufficiently flexible to permit it to be bent to form the corners of the board, as shown in FIG. 1. Furthermore, too thick a mat renders the board difficult to cut during installation. Such cuts are needed both for overall size and to fit the board around protrusions such as plumbing and electrical hardware.
[0033] The utility of the present mat is advantageous due to its controlled air permeability. During the gypsum board formation process, far more water is present in the gypsum slurry than is stochiometrically needed to drive the gypsum rehydration reaction. The excess is removed during a drying operation, and preferably escapes through the facings. The facers of the present invention must have sufficient permeability to allow the drying to be accomplished within an acceptable time period and without bubbling, delamination, or other degradation of the facer.
[0034] The invention further provides a method for making gypsum board and other hydraulic set and cementitious board products for interior and/or exterior use, i.e. products appointed for installation on either interior or exterior surfaces of building structures. By exterior surface is meant any surface of a completed structure expected to be exposed to weather; by interior surface is meant a surface within the confines of an enclosed, completed structure and not intended to be exposed to weather. The above-described non-woven, fibrous mat is present on at least one of the large faces of the gypsum board.
[0035] Gypsum wallboard and gypsum panels are traditionally manufactured by a continuous process. In this process, a gypsum slurry is first generated in a mechanical mixer by mixing at least one of anhydrous calcium sulfate (CaSO 4 ) and calcium sulfate hemihydrate (CaSO 4 ½H 2 O, also known as calcined gypsum), water, and other substances, which may include set accelerants, waterproofing agents, reinforcing mineral, glass fibers, and the like. The gypsum slurry is normally deposited on a continuously advancing, lower facing sheet, such as kraft paper. Various additives, e.g. cellulose and glass fibers, are often added to the slurry to strengthen the gypsum core once it is dry or set. Starch is frequently added to the slurry in order to improve the adhesion between the gypsum core and the facing. A continuously advancing upper facing sheet is laid over the gypsum and the edges of the upper and lower facing sheets are pasted to each other with a suitable adhesive. The facing sheets and gypsum slurry are passed between parallel upper and lower forming plates or rolls in order to generate an integrated and continuous flat strip of unset gypsum sandwiched between the sheets. Such a flat strip of unset gypsum is known as a facing or liner. The strip is conveyed over a series of continuous moving belts and rollers for a period of several minutes, during which time the core begins to hydrate back to gypsum (CaSO 4 2H 2 O). The process is conventionally termed “setting,” since the rehydrated gypsum is relatively hard. During each transfer between belts and/or rolls, the strip is stressed in a way that can cause the facing to delaminate from the gypsum core if its adhesion is not sufficient. Once the gypsum core has set sufficiently, the continuous strip is cut into shorter lengths or even individual boards or panels of prescribed length.
[0036] After the cutting step, the gypsum boards are fed into drying ovens or kilns so as to evaporate excess water. Inside the drying ovens, the boards are blown with hot drying air. After the dried gypsum boards are removed from the ovens, the ends of the boards are trimmed off and the boards are cut to desired sizes. The boards are commonly sold to the building industry in the form of sheets nominally 4 feet wide and 8 to 12 feet or more long and in thicknesses from nominally about ¼ to 1 inches, the width and length dimensions defining the two faces of the board.
[0037] The gypsum board production method can comprise the steps of: forming an aqueous slurry comprising at least one of anhydrous calcium sulfate, calcium sulfate hemi-hydrate, or cement; distributing the slurry to form a layer on a first facing; applying a second facing onto the top of the layer; separating the resultant board into individual articles; and drying the articles. The fibers in the web are bound together with a polymeric binder. Alternatively, the slurry may be distributed to form a layer between two facings. The slurry optionally includes reinforcing fibers or other known additives used as process control agents or to impart desired functional properties to the board, including one or more of agents such as biocides, flame retardants, and water repellents. The product of the invention is ordinarily of a form known in the building trades as board, i.e. a product having a width and a length substantially greater than its thickness. Gypsum and other hydraulic set and cementitious board products are typically furnished commercially in nominal widths of at least 2 feet, and more commonly 4 feet. Lengths are generally at least 2 feet, but more commonly are 8-12 feet.
[0038] Having thus described the invention in detail, it will be understood that such detail need not be strictly adhered to, but that additional changes and modifications may suggest themselves to one skilled in the art, all falling within the scope of the invention as defined by the subjoined claims.
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A novel coated nonwoven fibrous mat having properties particularly suited for a facer on gypsum wallboard, laminates made therefrom and the method of making the mat is disclosed. The mat preferably contains a major portion of glass fibers and a minor portion of a resinous binder. The coating is permeable and reduces fiber dust, and yields a smooth surface. The coating comprises mineral pigment and an organic binder.
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BACKGROUND OF THE INVENTION
The deterioration of paper, books and newspapers is a well-known and growing concern to librarians and archivists throughout the world. The causes of paper deterioration are numerous and include inherent acidity, photodegradation, oxidation, and even microbiological attack under certain conditions. These factors combined with initial paper quality have severely reduced the permanence of library and archival collections. A host of other phenomenon such as flood, fire, vandalism, etc. certainly add to these problems; however, it is becoming generally accepted that the most insidious problem is the acidity of most book paper produced in the last one hundred years.
The demand for large amounts of printing paper over the last century led to the introduction of pulp fiber produced from wood by chemical or mechanical means. However, paper made from untreated wood pulp is too absorbent to allow sharp image imprint. Therefore, chemicals have to be added to the wood fibers during processing. These additives allow the paper to accept inks and dyes and increase paper opacity. Unfortunately, most of these chemicals are either acidic or are deposited by acidic mechanisms which initiate the slow, but relentless acidic deterioration of paper. Other contributions to the acidification of paper are supplied by man through industrial emissions of sulphur and nitrogen and carbon oxides or by natural processes such as sea salt spray. Even books or paper of neutral and alkaline character are not immune. As neighboring papers of acidic nature degrade, volatile acids are produced which either diffuse through adjoining books or permeate the atmosphere and may ultimately acidify even the "safe or stable" books.
In order to arrest this acidic degradation, paper materials must be deacidified and provided with an alkaline reserve or buffer to retard a return to an acidic state. Currently, there are several processes either in various stages of development or commercialization for deacidifying paper whether bound or unbound. Numbering amoung these are processes using volatile metal alkyls e.g. U.S. Pat. Nos. 3,969,549, and 4,051,276, and volatile amines e.g. U.S. Pat. Nos. 3,472,611, 3,771,958 and 3,703,353. U.S. Pat. No. 3,676,182 issued July 11, 1972 describes the treatment of cellulosic materials with alkali and alkaline earth bicarbonates, carbonates, and hydroxides (Col. 17) in a halogenated hydrocarbon solvent or lower aliphatic hydrocarbon such as n-butane (Col. 7) with an optional plasticizing agent such as ethylene glycol (Col. 9). U.S. Pat. No. 3,676,055 issued July 11, 1972 to Smith describes a nonaqueous deacidification solution for treating cellulosic materials comprising 1000 cc of 7 percent magnesium oxide, (sic magnesium methoxide) in methanol and in addition 20 pounds of dichlorodifluoromethane (Freon 22). Canadian Pat. No. 911,110 issued Oct. 3, 1982 to Smith describes a deacidification solution (p 5) of a 7% magnesium methoxide solution in methanol (10 parts) and a halogenated solvent or solvents (90 parts); and states that a magnesium alkoxide reacts with water in paper to form a mildly alkaline milk of magnesia, being magnesium hydroxide (p 31). Improved results are reported with the use of the halogenated hydrocarbon solvents (p 40).
Unfortunately, all of these processes suffer from one or more of a number of drawbacks that have prevented their wide-spread acceptance. These drawbacks include high cost, toxicity, complexity of treatment, residual odor, deleterious effects on certain types of paper and inks, lack of an alkaline reserve, and the necessity of drying the book or paper to very low moisture contents before treatment.
BRIEF DESCRIPTION OF THE INVENTION
It has now been discovered that acidic cellulosic materials can be treated with non-toxic inexpensive materials in a manner which obviates or minimizes many of the problems of the prior art including the necessity for drying the book or paper prior to treatment. This method can be used on cellulosics (paper) even when such paper is imprinted and or bound. More particularly, it has been discovered that books, paper and other material having a cellulose base can be preserved by treatment with alkaline material particles of basic metal oxides, hydroxides or salts (hereinafter alternatively referred to as alkaline or basic material) in an amount and for a time sufficient to increase the acidic pH of the material and provide an alkaline buffer. Quite surprisingly, it is not necessary to neutralize the acids present within the confines of the treatment period. Rather, a basic metal oxide, hydroxide, or salt of suitable particle size is distributed through the cellulosic or paper web wherein these particles slowly stop and neutralize the acidic compounds present or produced during ageing. These basic materials are also present in sufficient amounts to buffer against reacidification by other acidic influences to which the paper may later be subjected to in storage.
The alkaline materials are regularly available materials and are preferably chosen from those which are relatively non-toxic. These particles are of such a size that they do not substantially interfere with any image, are colorless, and provide good coverage. Submicron or near submicron particles are suitable as these can be suspended in a gas or inert liquid which obviates the need for solutions or solvents which contribute to many of the drawbacks of current methods. Particles of these dimensions are also tightly held within the paper matrix and do not loosen under normal use. Typical BET surface areas range from 50 to 200 m 2 /g which provides high probabilty of acid contact and interdiction.
The invention will be further described in the following detailed description of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The cellulosic materials can be treated with any suitable basic metal oxide, hydroxide or salt. Suitable materials are the oxides, hydroxides, carbonates and bicarbonates of the Group 1 and 2 metals of the Periodic table and zinc. Preferred are the materials in which the cation is magnesium, zinc, sodium, potassium, or calcium. Particularly preferred are the relatively non-toxic oxides, carbonates and bicarbonates of magnesium and zinc and the hydroxides of sodium, potassium and calcium. Represenative examples include magnesium oxide, magnesium carbonate, magnesium bicarbonate, zinc carbonate, zinc bicarbonate, zinc oxide, sodium hydroxide, potassium hydroxide and calcium hydroxide. Magnesium oxide is most preferred. The predominant particle size (95-99%) is preferably between 0.01 and 0.9 micron, the average particle size is preferably between 0.2 and 0.6 micron and most preferably is about 0.4 micron. Typical surface areas are between 50 and 200 m 2 /g BET preferably about 170 m 2 /g.
The particles can be formed by burning the elemental metal and collecting the smoke, attrition of the preformed oxides or calcination of the elemental salts. For example, basic magnesium carbonate can be calcined at 450° C.-550° C. to produce a polydisperse high activity magnesium oxide with an average particle size of 0.4 microns and a predominant particle size between 0.1 and 0.9 micron.
The particles can be applied in the paper making process or to the finished paper by electrostatic transfer such as in a xerographic process, by a dispersion in a gas, or by a suspension in an inert liquid. In the case of a liquid suspension of the particles, the liquid chosen is preferably inert and possessing a high enough vapor pressure to allow its removal from the book or paper after exposure. Liquids which are well suited for this purpose are halogenated hydrocarbons. Typical materials include Dupont Freon Fluorcarbons such as Freon 11 (trichloromonofluoromethane), Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane), and Freon 114 (1,2-dichloro-1,1,2,2-tetrafluoroethane, and Allied Chemical Genetron 11 and 113 and mixtures. The suspension is less prone to settling and/or agglomeration if a surfactant is employed to overcome surface tension and charge attraction effects. Typical materials include surfactants such as ICI Solsperse 6000 and 3000 and 3M Fluorad FC 740 and 721. Mixtures of these surfactants can be employed. A preferred surfactant is a fluorinated alkyl ester known as Fluorad FC 740.
The amount of surfactant and alkaline material will depend in part on the length of treatment and the amount of deposition desired. Generally, however, the concentration of alkaline material will be between about 0.01% and about 0.3% and the surfactant between about 0.005% and about 1.0%. A most preferred range for the basic material particles is between about 0.01% and about 0.2%, and a most preferred range for the surfactant is between about 0.005% and about 0.5%.
In the case of unbound or single sheets of paper, deposition may take place using a gas or air supported dispersion. Active methods of deposition enhancement such as aerosol impingement, filtering through the paper and electrostatic attraction have proved promising for increasing the rate of deposition. Impingement of the gas supported dispersion on the paper combined with electrostatic attraction is particularly effective. In this method, paper is placed against a charged plate and the field so created is used to attract the particles to the paper.
The preferred method for bound sheet materials such as books or manuscripts is the use of a suspension in a liquid. The liquid is used not only to disperse the particles, but also to open the bound material to provide uniform treatment. By the use of spray nozzles or motion imparted to the bound material while submerged, pages can be easily separated and exposed to the particles. In a liquid suspension, one is able to obtain a higher concentration of particles in the treating media and deposit the necessary amount of alkaline material in a shorter time. By the use of halogenated hydrocarbon/surfactant combinations, the stable concentration of submicron particles can be increased from 20-30 milligrams/cubic foot in a gas to 1-100 grams/cubic foot in a liquid. At the higher concentrations, one immersion into the treating medium for a few seconds will usually suffice to deposit the required amount of basic material. At the lower concentrations, two or more immersions or a longer immersion time is required to achieve the same effect. After immersion, the inert liquid is evaporated, recovered and recycled.
The following examples will serve to illustrate the invention. All parts and percentages in the specification and claims are by weight, unless otherwise indicated.
EXAMPLE 1
Sample imaged acidic sheets were treated with an air supported dispersion of MgO powder (average 0.4 micron particle size with a predominant particle size between 0.01 and 0.9 micron and a concentration of 25 mg/cubic foot). The sheets were hung in a glove box adapted to control the humidity at 32% and the initial temperature was 22° C. at standard atmosphere. The particles were transported to the glove box through lines connected to the exhaust of a Trost Air Mill. After a three hour exposure to the static air dispersion, the pH of the paper increased to 6.6 from an intial pH of 4.4 and the image was not impared.
EXAMPLE 2
Three sample imaged acidic sheets with a pH of 4.3 were dried in an oven at 50° C. for one hour and then placed in a glove box at conditions described in Example 1. Then a magnesium oxide dispersion in air as described in Example 1 was pumped into the box, and a container of warm water (40° C.) was uncovered. The relative humidity went from 34 to 94% in ten minutes and the water container was closed after ten minutes and the dispersion treatment was discontinued in 11/2 hours. The humidification treatment of the paper increased the deposition rate by more than two fold over that in Example 1. The sample sheets facing the dispersion had a pH from 7.2 to 8.7.
EXAMPLE 3
A sheet of imaged acidic book paper (pH 4.0) was placed in contact with the charged sphere of an electrostatic generator (WINSCO Model N 100-v). A stream of dispersed particles described in Example 1 was directed against the paper for approximately 5 seconds. The pH of the paper after exposure was 8.5, and the image was not imparied.
EXAMPLE 4
A liquid treating suspension was prepared by adding 3.2 G. (0.20%) of MgO (prepared by calcining basic hydromagnesite at 500° C. for 3 Hours) to 1000 ml. of Allied Chemical Genetron - 113 containing 0.78 g (0.05%) of 3M Fluorad FC 740 surfactant. This suspension was used to treat single sheets of imaged acidic book paper by submerging each sheet into the suspension for 20 seconds. The sheets were then air-dried. These sheets (40) along with an equal number of untreated sheets were subjected to accelerated ageing according to TAPPI standard T 453 m-48 for up to 28 days. After samples were removed from the oven, the folding endurance test values of the paper were determined by using an MIT folding endurance tester (TAPPI standard T 511 su-69). The pH values were determined with a flat probe electrode according to TAPPI standard T 529 pm-74. The results were as follows:
______________________________________ACCELERATED AGEING TESTS AT 105° C. EFFECTON M.I.T. FOLD ENDURANCE AND pHTime in Days Untreated Treatedat 105° C. Fold pH Fold pH______________________________________ 0 108 6.4 105 9.414 43 6.0 97 8.128 7 5.4 35 8.2______________________________________ Note: Fold endurance is the number of double folds under a 0.5 Kg. tensio before failure. Paper is considered brittle and unusable at 5 or less folds.
This paper was from a book 37 years old. The only method presently available to determine the effects of treatment is to subject the paper to some form of accelerated ageing, in this case dry heat, and directly compare the strength retention of treated and untreated samples as shown above. The increase in life expectancy can be estimated by converting the folding endurance test values to logrithmic values and computing the regression equations of the treated and untreated paper with respect to time of accelerated ageing. Then the slopes of the resultant equations are directly compared. When this method was applied to the data above, the life expectancy of the treated paper was increased two and one-half times over its untreated counterpart.
EXAMPLE 5
The liquid suspension prepared as in Example 4 was used on a newer book (age six years) with a much higher initial fold endurance. Paper taken from this book had an average pH of 5.0. After treatment as described in Example 4, the treated paper had an average pH of about 9.0. The results of accelerated ageing are shown below:
______________________________________ACCELERATED AGEING TESTS -EFFECT ON M.I.T. FOLD ENDURANCEEXPOSURE TIME 105° C. 70° C. SAT'D R.H.DAYS UNT'D TRT'D UNT'D TRT'D______________________________________ 0 1656 1656 1406 1390 7 281 498 933 116014 19 149 619 96921 2 45 410 80928 0 2 272 676______________________________________
The accelerated ageing at 70° C. in a water saturated atmosphere was done to show the effects of moisture during exposure. Although the paper lost strength slower at the moist conditions probably due to the lower temperature, acidic hydrolysis was probably enhanced. This was indicated by the pH decreases before and after exposure. The pH of the untreated paper dropped from 5.0 to 4.5 after 28 days in the dry oven, but fell to 3.7 under moist conditions. The treated samples remained about pH 9.0 in the dry oven, but fell to pH 6.6 in the moist oven after 28 days. These results indicate an increase of almost twofold in expected shelf life by dry oven ageing and somewhat more than that by moist oven ageing. Samples were removed after treatment and again after 14 days of dry oven exposure and measured for brightness. This was done when it was noticed that the treated samples appeared much whiter than the untreated samples after dry oven exposure. The brightness measurements were taken according to TAPPI standard T 452. The untreated paper fell in brightness from an average of 73.7 to 65.6, about 12%, that of the treated samples fell from 74.4 to 69.5, about 7%.
EXAMPLE 6
A 30-gallon capacity tank was filled with 20 gallons of treating suspension as described in Example 4. A bound manuscript (average pH 3.9) characterized as having a strong binding was placed with its spine against the angle of a V-shaped metal tray (angle 90 degrees). The assembly was weighted and lowered vertically (book spine perpendicular to the tank bottom) into the suspension. The bottom edge of the book block was approximately an inch above the tank bottom. A low impact, wide deflection, flat pattern spray nozzle was directed to spray downwards against the top edge of the book. The flow rate was one and one-half gallons per minute. The effect of the spray fanned the pages of the book very evenly. After five minutes, the book was removed and placed into a vacuum oven. The chamber was evacuated for 45 minutes during which time almost 100% of the fluorocarbon liquid was recovered in a refrigerated trap. Several random pH measurements on the book indicated values from 8.5-8.7. An indicator, bromocresol purple, was brushed on several pages and showed that the method used results in excellent uniformity with no image impairment.
EXAMPLE 7
The tank used in Example 6 was filled with 20 gallons of a suspension consisting of 0.3 grams (0.02%) of submicron magnesium oxide with 0.15 grams (0.01%) of Fluorad FC 740 surfactant per liter. A bound volume (average pH 4.1) characterized as having a weak binding was secured to the same V-shaped tray as described in Example 5. The assembly was lowered into the suspension with the foreedge of the book pointed up. After allowing the book to seperate for three minutes, the book was gently moved up and down in the suspension for an additional two minutes. Before removing the book, one cover was freed and the assembly was rotated 45 degrees in a direction opposite from the free edge. As the volume was withdrawn from the suspension, the book closed freely with little or no stress applied on the binding. The pH after after air drying varied from 6.1 to 7.3 with no image impairment.
While the invention has been illustrated with the use of MgO, other alkaline materials can be used in similar or like amounts. Similarly, other surfactants and inert volatile liquids for the disperions may be obvious to one skilled in the art.
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A method is provided of deacidifying books, imaged paper and other imaged material having a cellulose base comprising treating said material with suitable alkaline particles of basic metal oxide, hydroxide or salt dispersed in a gas or liquid in an amount and for a time sufficient to increase the pH of the material and provide an alkaline buffer without impairing the image thereon, said liquid consisting essentially of an inert halogenated hydrocarbon and a surfactant.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is broadly concerned with a solar powered lantern device such as a buoy or the like which is luminescent at night, is constructed of interchangeable components for varying the signal markings and color of the signal light, and which emits a beacon visible from all directions. More particularly, it is concerned with a lantern having modular housing components, a reflective internal support frame, a pair of cone-shaped reflectors, and a mounting assembly which permits the device to be moored in the water or mounted atop a pole.
2. Description of the Related Art
Solar powered lantern devices are preferable in many instances to conventional electrical and hydrocarbon fueled lanterns because they do not require connection to an external electrical power source or frequent refueling. They are especially well-suited for use as maritime buoy markers or signals. Since malfunction of the photovoltaic power system can cause failure of the beacon, such markers are commonly coated with a fluorescent material so that they will maintain a measure of nighttime visibility. In this manner, the buoy reflects light from approaching craft. Such coatings are impermanent however, and are subject to degradation such as flaking and peeling upon prolonged exposure to the elements.
The maritime buoyage system in common use employs a system of color coding of the top, middle, and bottom of the buoy as well as the beacon to identify direction, danger and safe water areas. Unless a buoy is to be permanently dedicated to a single marking use, it must be remarked to the appropriate color code prior to removal to a differently coded location. While permanent color coding may be accomplished by selective painting or coating of the buoy, such coatings are impermanent, and may not easily be changed.
Where a single lighting element is employed, it is generally mounted atop the buoy, rather than in the center. Such top-mounted beacons are subject to damage by debris, boats, and waterskiers, as well as fouling by birds. Where a reflector is employed to enhance the visibility of the light, it serves to shade the beacon light in the non-reflective direction.
U.S. Pat. Nos. 4,809,458 issued to Tanikuro et al. and 4,626,852 issued to Dodge do not permit interchangeable buoy marking components, do not reflect light to the area below the lower hemisphere of the buoy, and do not provide a weather-shielded reflector element in case the lighting element fails.
SUMMARY OF THE INVENTION
The present invention overcomes the problems previously outlines and provides a greatly improved solar powered lantern device which is visible even without a beacon under reflected light and which can be easily color coded to conform to the marking requirements of a new location. Broadly speaking, the lantern device includes a housing, a lighting element supported by a luminescent internal frame, a photovoltaic power supply, and an omnidirectional reflector.
In particularly preferred forms, the lantern device is a buoy having a modular housing with interchangeable colored elements. A lighting element is centrally supported inside the housing by a luminescent frame, which also serves to reflect light from approaching craft when the lighting element fails. The lantern device may be also be mounted atop a pole. In preferred forms the frame is hollow and forms a conduit for electrical conductors from the power supply to the lighting element. A pair of conical reflectors is positioned within the housing to reflect the beacon light omnidirectionally.
OBJECTS AND ADVANTAGES OF THE INVENTION
The principal objects and advantages of the present invention include: providing a solar powered lantern device which may be employed as a buoy or mounted atop a pole; providing such a device including a luminescent material for reflecting light under conditions of beacon failure; providing such a device which includes a luminescent internal support frame; providing such a device having a hollow support frame which forms a conduit for electrical conductors from the power supply to the lighting element; providing such a device having a lighting element which is centrally supported inside the housing; providing such a device having a modular housing constructed of interchangeable elements; providing such a device having an omnidirectional reflector for 360° reflection of the beacon light; providing such a device including a photovoltaic power supply including a solar panel, a storage battery, and electrical conductors; providing such a device which includes a flashing beacon; providing such a device which includes a transparent lens portion; providing such a device which includes a photosensor and photoswitch for automatic switching on of the beacon in darkness and off in daylight; providing such a device which is floatable in the water in an upright position; providing such a device which may be moored to a selected location.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the solar powered lantern of the invention employed as a buoy;
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1;
FIG. 3 is a schematic diagram of the lighting assembly electrical circuit; and
FIG. 4 is an outline of an alternate embodiment of the lantern of the invention having modular housing components and adapted for mounting atop a pole.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
I. Introduction and Environment
Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words "upwardly", "downwardly", "rightwardly" and "leftwardly" will refer to directions in the drawings to which reference is made. The words "inwardly" and "outwardly" will refer to directions toward and away from, respectively, the geometric center of the embodiment being described and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof and words of a similar import.
II. Solar Powered Lantern Device
It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown.
Referring now to the drawing, a solar powered lantern device 10 in accordance with the invention broadly includes a housing 12, lighting assembly 14, flotation assembly 16, and mounting assembly 18.
In more detail, generally cylindrical housing 12 includes a top cover 20, and a bottom portion 22. Bottom portion 22 includes a transparent upper lens portion 24, and a lowermost bottom cover 26. Bottom cover 26 may be integrally constructed to include a transparent lens portion 24 as depicted in FIG. 2, or the lens may be of separate construction, as depicted in FIG. 4. Housing 12 and top and bottom covers 20, 26 are preferably formed of synthetic resinous material or fiberglass, although they may also be constructed of metal, or any other suitable material. They may also be constructed to cooperatively form any geometric configuration, such as a sphere, or fanciful figure, such as a frog or fish. Lens 24 may be formed of any suitable transparent material such as a synthetic resinous material, or even of glass, and may be tinted so that a colored signal beacon is emitted. Housing 12, top and bottom covers 20, 26, and lens 24 may also be colored in conventional maritime signal colors, or in fluorescent or fanciful colors.
Top 20 includes outstanding apertured flanges 28 located at spaced intervals for accommodating retaining screws 30. The uppermost portion of lens 24 similarly includes outstanding apertured flanges 32 located at corresponding spaced intervals and including sleeves for mating engagement with screws 30. As depicted in FIG. 4, where lens 24 is of separate construction, the lowermost portion of lens 24 and bottom 22 each include outstanding apertured flanges 34, 36 at corresponding spaced intervals. Seals 38, 40 fit between flanges 28, 32 and 34, 36 respectively for maintaining housing 12 in watertight condition. Where bottom cover 26 is of unitary construction with lens 24, flanges 34, 36 and lower seal 40 are omitted. The center portion of bottom cover 26 includes a socket 42, which may be threaded.
As best shown in FIGS. 2 and 3, lighting assembly 14 includes a photovoltaic solar panel 44, a charging circuit 46, battery pack 48, photo sensor 50, lighting element 52, and pair of reflectors 54, 56.
Solar panel 44 is generally comprised of a series of individual converters. In preferred forms a photovoltaic cell such as Solarex MSX01 is employed. Charging circuit 46 regulates the voltage and current produced by solar panel 44 to ensure that it is compatible with battery 48. Circuit 46 includes a circuit board (not shown), electrical conductors 58 (only two are shown), and a switch 60 having on, off, and automatic positions. Battery pack 48 preferably consists of two size C nickel-cadmium rechargeable batteries, although conventional batteries may be employed and the solar panel omitted in smaller buoys used, for example, on trot lines. Photo sensor eye 50 is coupled with a photo switch 62, which switches the circuit on or off depending on the ambient light level, and a flasher element 64. Those skilled in the art will appreciate that photo sensor 50 and photo switch 62 may be combined in a single unit such as a phototransistor. Lighting element 52 includes a support assembly 66 having a series of legs 68, coupled with a pair of generally circular members 70, 72, which in turn are coupled in spaced relationship by vertical support members 74 to cooperatively form a cage for supporting and protecting lighting element 52. Upper and lower sockets 76, 78 couple lighting element 52 with upper and lower circular members 70, 72, respectively.
In preferred forms, support assembly 66 is formed of hollow, luminescent (such as fluorescent) synthetic resinous tubing material so as to serve as a protective conduit for electrical conductors 58. In other preferred forms, electrical conductors 58 may be integrally molded into solid tubing material. Those skilled in the art will appreciate that support assembly 66 can be constructed in any of a number of alternate configurations and should not be limited to the configuration described.
Lighting element 52 may be a conventional filament-type bulb or a fluorescent-type bulb, coupled with a single socket, or with a pair of sockets in generally vertical orientation as depicted in FIG. 2, or any other suitable light-emitting element coupled in generally horizontal or other orientation. Reflectors 54, 56 are generally conical or parabolic in shape and are mounted by support assembly legs 68 in spaced relationship to lighting element 52 so that emitted light is reflected omnidirectionally, for 360° visibility of the buoy. In preferred forms each reflector is constructed so as to present a multifaceted prismatic surface. In especially preferred forms, the reflectors are constructed of a light weight, flexible reflective material such as, for example, Alcoa Everbrite.sub.™, or any other suitable reflective material.
Flotation assembly 16 includes a ballast container 80, which is filled with ballast 82 such as sand, rocks or any other ballast material. An identifier plate or other signage may be inserted between container 80 and housing 12 so that it is visible through lens 24.
Mounting assembly 18 includes a hook 84, such as an eye hook having a shank 86 which extends upwardly through apertured bottom socket 42 and is anchored into ballast 82. Hook shank 86 may also be transversely coupled with the center of a flattened disc. Lantern 10 can be floated on the water as a buoy and anchored to a sinker (not shown) by a line 88 or a chain. Lantern 10 may also be mounted atop a pole 90, which may in turn be attached to a floating buoy or to a dock, boat, or any other suitable object.
III. Operation
Lantern device is mounted atop a buoy or pole 90 by coupling threaded socket 42 with a correspondingly threaded fitting. Alternatively, it may be floated in the water and anchored to a sinker by a line 88 coupled with eyehook 84. A user sets switch 60 to the "on" position to operate the light continuously, or to the "automatic" position to permit activation of the beacon by a photosensor when ambient light decreases below a predetermined level.
During periods of full or partial sunshine, light rays strike photoreceptors in the solar panel 44, where they are converted to electrical energy and transmitted through charging circuit 46 to rechargeable battery cells 48 for storage. Upon manual activation of switch 60, or activation of photo switch 62 by photo sensor 50, electrical energy is delivered from battery 48 to light element 52 to produce a beacon. If a flasher is included in the circuitry, a flashing beacon is emitted. The emitted light is mirrored in all directions by conical reflector elements 54, 56, so that the lantern is visible from all angles, including underwater.
During periods of low light, boats and other sources of light are reflected from luminescent light element support assembly 66, so that the buoy is visible in the lights of oncoming boat traffic even if the light element fails.
The top and bottom markings of the buoy and the color of the beacon emitted can be altered by uncoupling modular top, bottom and lens housing elements and interchanging them with similar modular elements of different colors.
Lantern device 10 may also be assembled by a user from a kit comprised of component parts by placing seal 40 between bottom cover 26 and lens 24, aligning bottom cover and lens flanges 36, 34 respectively, and inserting retaining screws, loading ballast container 80 with any commonly available ballast, and installing it over bottom cover 26. A reflector 56 is next installed over ballast container 80, followed by light element support assembly 66, fitted with lighting element 52. Top reflector 54 is inserted atop support assembly legs 68, followed by battery 48 and seal 40. Preassembled top cover 20 includes electrical conductors 58, which are coupled with battery 48, prior to insertion of seal 38. Top cover and lens flanges 28, 32 are aligned and screws 30 are inserted.
Having described the preferred embodiments of the present invention, the following is claimed as new and desired to be secured by letters Patent.
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A solar powered lantern device is visible even without a beacon under reflected light and can be easily color coded to conform to the marking requirements of a new location. The lantern device includes a housing, a lighting element supported by a luminescent internal frame, a photovoltaic power supply, and an omnidirectional reflector. In particularly preferred forms, the lantern device is a buoy having a modular housing with interchangeable colored elements. A lighting element is centrally supported inside the housing by a luminescent frame, which serves to reflect light from approaching craft when the lighting element fails. The device may also be mounted atop a pole. In preferred forms the frame is hollow and forms a conduit for electrical conductors from the power supply to the lighting element. A pair of conical reflectors is positioned within the housing to reflect the beacon light omnidirectionally.
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FIELD OF THE INVENTION
Embodiments of the invention relate to semiconductor devices and, in particular, to phase change memory elements and methods of forming and using the same.
BACKGROUND OF THE INVENTION
Non-volatile memories are useful elements of integrated circuits due to their ability to maintain data absent a power supply. Phase change materials have been investigated for use in non-volatile memory cells. Phase change memory elements include phase change materials, such as chalcogenide alloys, which are capable of stably transitioning between amorphous and crystalline phases. Each phase exhibits a particular resistance state and the resistance states distinguish the logic values of the memory element. Specifically, an amorphous state exhibits a relatively high resistance, and a crystalline state exhibits a relatively low resistance.
A conventional phase change memory element 1 , illustrated in FIGS. 1A and 1B , has a layer of phase change material 8 between first and second electrodes 2 , 4 , which are supported by a dielectric material 6 . The phase change material 8 is set to a particular resistance state according to the amount of current applied between the first and second electrodes 2 , 4 . To obtain an amorphous state ( FIG. 1B ), a relatively high write current pulse (a reset pulse) is applied through the conventional phase change memory element 1 to melt at least a portion 9 of the phase change material 8 covering the first electrode 2 for a first period of time. The current is removed and the phase change material 8 cools rapidly to a temperature below the crystallization temperature, which results in the portion 9 of the phase change material 8 covering the first electrode 2 having the amorphous state. To obtain a crystalline state ( FIG. 1A ), a lower current write pulse (a set pulse) is applied to the conventional phase change memory element 1 for a second period of time (typically longer in duration than the crystallization time of amorphous phase change material) to heat the amorphous portion 9 of the phase change material 8 to a temperature below its melting point, but above its crystallization temperature. This causes the amorphous portion 9 of the phase change material 8 to re-crystallize to the crystalline state that is maintained once the current is removed and the conventional phase change memory element 1 is cooled. The phase change memory element 1 is read by applying a read voltage, which does not change the phase state of the phase change material 8 .
One drawback of conventional phase change memory is the large programming current needed to achieve the phase change. This requirement leads to large access transistor design to achieve adequate current drive. Another problem associated with the memory element 1 , is poor reliability due to uncontrollable mixing of amorphous and polycrystalline states at the edges of the programmable volume (i.e., portion 9 ). Accordingly, it is desirable to have phase change memory devices with reduced programming requirements and increased reliability. Additionally, since in the memory element 1 , the phase change material 8 is in direct contact with a large area of the first electrode 2 , there is a large heat loss resulting in a large reset current requirement.
Accordingly, alternative designs are needed to address the above noted problems.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B illustrate a conventional phase change memory element.
FIG. 2 illustrates partial cross-sectional view respectively of a phase change memory device according to an embodiment of the invention.
FIGS. 3A-3D illustrate top-down views of the phase change memory device of FIG. 2 along the line 3 - 3 ′ according to embodiments of the invention.
FIGS. 4A-4D illustrate partial cross-sectional views of a method of fabricating the phase change memory device of FIGS. 2A and 2B .
FIG. 5 is a partial cross-sectional view of the phase change memory device of FIG. 2 showing additional circuitry according to an embodiment of the invention.
FIG. 6 is a block diagram of a processor system having a memory device incorporating a phase change memory element constructed in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description, reference is made to various embodiments of the invention. These embodiments are described with sufficient detail to enable those skilled in the art to practice them. It is to be understood that other embodiments may be employed, and that various structural, logical and electrical changes may be made.
The term “substrate” used in the following description may include any supporting structure including, but not limited to, a semiconductor substrate that has an exposed substrate surface. A semiconductor substrate should be understood to include silicon, silicon-on-insulator (SOI), silicon-on-sapphire (SOS), doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor foundation, and other semiconductor structures, including those made of semiconductors other than silicon. When reference is made to a semiconductor substrate or wafer in the following description, previous process steps may have been utilized to form regions or junctions in or over the base semiconductor or foundation. The substrate also need not be semiconductor-based, but may be any support structure suitable for supporting an integrated circuit, including, but not limited to, metals, alloys, glasses, polymers, ceramics, and any other supportive materials as is known in the art.
Embodiments of the invention provide phase change memory devices having planar memory elements. The embodiments are now explained with reference to the figures, which illustrate embodiments and throughout which like reference numbers indicate like features. FIG. 2 illustrates a cross-sectional view of a portion of a phase change memory device 200 constructed in accordance with embodiments of the invention. FIGS. 3A-3D are top-down views of a portion of the memory device 200 along the line 3 - 3 ′ according to the embodiments.
The memory device 200 includes memory elements 201 , each for storing at least one bit, i.e., logic 1 or 0. As described in more detail below, the memory elements 201 are planar and configured to have a reduced programming volume and/or programming voltage as compared to the memory element 1 ( FIG. 1A ).
Referring to FIG. 2 , conductive plugs 14 are formed within a first dielectric layer 20 and over a substrate 11 . As shown in FIG. 5 and described in more detail below, the substrate 11 can include additional devices and structures. Each memory element 201 is formed over and in communication with a respective conductive plug 14 . Each memory element 201 includes a layer of phase change material 16 and self-aligned first and second electrodes 31 , 32 . Each first electrode 31 is in contact with a respective conductive plug 14 . Alternatively, more than one first electrode 31 can be in contact with a same conductive plug 14 . Each second electrode is in contact with a conductive interconnect 40 , which is connected to a second electrode select line 546 ( FIG. 5 ).
In the memory elements 201 , the first electrode 31 and second electrode 32 are at opposing ends of the phase change material 16 at least partially along a same horizontal plane. Thus, the memory elements 201 are planar. In the illustrated embodiment, the phase change material layer 16 is vertically disposed between second and third dielectric layers 17 , 18 . The phase change material layer 16 and second and third dielectric layers 17 , 18 are arranged in a stack 211 . The first and second electrodes 31 , 32 are formed on sidewalls of the stack 211 .
As shown in FIG. 3A , from a top-down perspective, the stack 211 , including the phase change material layer 16 , has a variable width (e.g., widths 316 a , 316 b ) along the length 317 of the phase change material layer 16 . For purposes of this specification, the length of the phase change material layer is measured along the distance between the first and second electrodes 31 , 32 from the top-down perspective of FIG. 3A . The width of the phase change material layer 16 is measured along the distance perpendicular to the length as indicated in FIG. 3A .
In the embodiment of FIG. 3A , the portions of the phase change material layer 16 adjacent the electrodes 31 , 32 have a greater width 316 a than the width 316 b of a portion of the phase change material layer 16 at a distance between the electrodes 31 , 32 . The width of the phase change material layer 16 of FIG. 3A is shown progressively decreasing linearly from each electrode 31 , 32 to approximately the center 315 having width 316 b . It should be understood that the narrowest portion of the phase change material layer 16 need not be centered between the electrodes 31 , 32 , but can instead be closer to one or the other of the electrodes 31 , 32 .
FIGS. 3B-3D are top-down views of a portion of the memory device 200 along the line 3 - 3 ′ according to other embodiments. As shown in FIG. 3B , the portion of the phase change material layer having a narrow width is extended as compared to that shown in FIG. 3A . Alternatively, as shown in FIGS. 3C and 3D , the width of the phase change material layer progressively decreases in a step-wise manner from each electrode 31 , 32 to approximately the center 315 having width 316 b . Further, while the phase change material layer 16 is shown having a narrowest width at the center 315 , the phase change material layer 16 can have a narrowest width at other points. Further other shapes, e.g., an hourglass shape among others, are possible such that the phase change material layer 16 varies in width between the first and second electrodes 31 , 32 .
By providing a narrow width 316 b between the electrodes 31 , 32 , during operation, current crowding is induced and the programmable volume 16 a corresponds to a region of the phase change material layer 16 at and adjacent to the portion having the narrow width 316 b . This reduces heat loss through the electrodes 31 , 32 . This configuration enables better scalability since the scale would not be limited by electrode 31 , 32 heat loss. The induced current crowding also enables a full reset state of the programmable volume 16 a to improve the on/off resistance ratio of the element 201 and reduce the threshold voltage. Additionally, the programmable volume 16 a and programming voltages can be reduced as compared to that in a conventional vertical memory element 1 ( FIG. 1A ).
The memory device 200 is operated to have two or more resistance states. This is accomplished by applying a reset current pulse to change the programmable volume 16 a of the phase change material 16 between the crystalline and amorphous states. If, for example, three resistance states are desired, the reset current is controlled to change a second programmable volume 16 b between the crystalline and amorphous states. Additional resistance states are achieved by controlling the reset current pulse to change additional programmable volumes between the crystalline and amorphous states. Thus, the device 200 can be operated such that the phase change material layers 16 of the elements 201 have more than one programmable volume. Compared to multi-state programming in conventional memory devices, the device 200 enables improved stability, repeatability, reliability and consistency since the programmable volume 16 a can be provided at a distance from the electrodes and the phase change can be complete.
Referring to FIGS. 2 and 3 , each first electrode 31 is over and in contact with a respective conductive plug 14 . Each second electrode is in contact with a conductive interconnect 40 formed in a fourth dielectric layer 21 . As depicted in FIG. 2 , the conductive interconnect 40 is formed between and self-aligned to the second electrodes 32 of adjacent memory elements 201 .
FIGS. 4A-4D illustrate one embodiment of fabricating the phase change memory device 200 illustrated in FIGS. 2-3D . No particular order is required for any of the actions described herein, except for those logically requiring the results of prior actions. Accordingly, while the actions below are described as being performed in a specific order, the order can be altered if desired.
As shown in FIG. 4A a first dielectric layer 20 is formed over a substrate 11 . The first dielectric layer 20 is etched to create vias 424 within which conductive plugs 14 are formed. The conductive plugs 14 are formed of any suitable conductive material, such as titanium-nitride (TiN), titanium-aluminum-nitride (TiAlN), titanium-tungsten (TiW), platinum (Pt) or tungsten (W), among others.
As depicted in FIG. 4B , a second insulating layer 17 , a phase change material layer 16 and a third insulating layer 18 are deposited over the conductive plugs 14 and the first insulating layer 20 . The layers 16 , 17 , 18 are formed as blanket layers. The programmable volume 316 ( FIGS. 3A-3D ) is adjusted by adjusting the thickness of the phase change material layer 16 .
In the illustrated embodiment, the phase change material 16 is a chalcogenide material, for example, germanium-antimony-telluride and has a thickness of, for example, about 100 Å. The phase change materials can also be or include other phase change materials, for example, In—Se, Sb2Te3, GaSb, InSb, As—Te, Al—Te, GeTe, Te—Ge—As, In—Sb—Te, Te—Sn—Se, Ge—Se—Ga, Bi—Se—Sb, Ga—Se—Te, Sn—Sb—Te, In—Sb—Ge, Te—Ge—Sb—S, Te—Ge—Sn—O, Te—Ge—Sn—Au, Pd—Te—Ge—Sn, In—Se—Ti—Co, Ge—Sb—Te—Pd, Ge—Sb—Te—Co, Sb—Te—Bi—Se, Ag—In—Sb—Te, Ge—Sb—Se—Te, Ge—Sn—Sb—Te, Ge—Te—Sn—Ni, Ge—Te—Sn—Pd, and Ge—Te—Sn—Pt.
FIG. 4C illustrates the patterning and etching of the layers 16 , 17 , 18 into stacks 211 for individual memory elements 201 . Also, a conformal conductive layer is formed over the stacks 211 . A spacer etch is performed to form the self-aligned electrodes 31 , 32 as sidewalls on the stacks 211 . The electrodes 31 , 32 are formed of any suitable conductive material, such as titanium-nitride (TiN), among others. The stacks 211 are each formed partially overlying a respective conductive plug, such that when the first electrodes 31 are formed on a sidewall of the stacks 211 , the first electrodes 31 are in contact with a respective conductive plug 14 .
The stacks 211 are further patterned and a dry etch step is conducted to shape the stacks, including the phase change material layer 16 to have a shape shown in one of FIGS. 3A-3D or as desired and in accordance with the invention.
As shown in FIG. 4D , a fourth dielectric layer 21 is formed over the stacks 211 and electrodes 31 , 32 . A via 440 is formed in the fourth dielectric layer 21 to expose the second electrodes 32 of adjacent memory elements 201 . To achieve the structure shown in FIG. 2 , a conductive material is deposited within the via 440 self-aligned to and in contact with the second electrodes 32 .
Additional structures can be formed to complete the memory device 200 . For example, bit line 544 , word lines 541 , second electrode select line 546 and conductive interconnects 542 , as shown and described below in connection with FIG. 5 .
FIG. 5 is a partial cross-sectional view of the phase change memory device of FIG. 2 showing additional circuitry according to an embodiment of the invention. The memory elements 201 overlie bit line 544 , word lines 541 and conductive interconnects 542 , which are supported by substrate 10 . Isolation regions 550 within the substrate 10 isolate the various elements of the memory device 200 . The structure shown in FIG. 5 is only one example and other circuit designs including one or more memory elements 201 and/or the memory device 200 according to embodiments of the invention are contemplated as within the scope of the invention.
FIG. 6 illustrates a simplified processor system 600 which includes a memory circuit 626 having a phase change memory device 200 constructed in accordance with the invention.
The FIG. 6 processor system 600 , which can be any system including one or more processors, for example, a computer, PDA, phone or other control system, generally comprises a central processing unit (CPU) 622 , such as a microprocessor, a digital signal processor, or other programmable digital logic devices, which communicates with an input/output (I/O) device 625 over a bus 621 . The memory circuit 626 communicates with the CPU 622 over bus 621 typically through a memory controller. The memory circuit 626 includes the memory device 200 ( FIGS. 2-3 ). Alternatively, the memory circuit 626 can include one or more of the memory elements 201 .
In the case of a computer system, the processor system 600 may include peripheral devices such as a compact disc (CD) ROM drive 623 and hard drive 624 , which also communicate with CPU 622 over the bus 621 . If desired, the memory circuit 626 may be combined with the processor, for example CPU 622 , in a single integrated circuit.
The above description and drawings are only to be considered illustrative of specific embodiments, which achieve the features and advantages described herein. Modification and substitutions to specific process conditions and structures can be made. Accordingly, the embodiments of the invention are not to be considered as being limited by the foregoing description and drawings, but is only limited by the scope of the appended claims.
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Phase change memory elements, devices and systems using the same and methods of forming the same are disclosed. A memory element includes first and second electrodes, and a phase change material layer between the first and second electrodes. The phase change material layer has a first portion with a width less than a width of a second portion of the phase change material layer. The first electrode, second electrode and phase change material layer may be oriented at least partially along a same horizontal plane.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a suspension unit having a magneto-spring unit and metal springs and, in particular but not exclusively, to a suspension unit having a spring constant of substantially zero in a predetermined range by combining a magneto-spring unit having a negative spring constant and metal springs having a positive spring constant.
2. Description of the Related Art
In recent years, vehicle technologies including automobile technologies have been remarkably developed, and safety and riding-comfort as well as maneuverability are desired. Recently, with the practical use of permanent magnets that have a high coercive force and a high residual magnetic flux density, research is flourishing in areas such as mechanical structures and magnetic systems that utilize magnetic levitation, magnetic bearings, dampers employing a magnetic fluid, or the like. The inventors of this application have hitherto proposed suspension units in which a magneto-spring is utilized.
However, in a suspension unit having a spring constant of substantially zero in a predetermined range by combining a magneto-spring having a negative spring constant and metal springs having a positive spring constant, a large stroke results in a very large unit.
SUMMARY OF THE INVENTION
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide a relatively compact suspension unit that ensures a large stroke by making the amount of motion of the magneto-spring unit be smaller than that of the suspension unit.
In accomplishing the above and other objectives, the suspension unit according to the present invention includes a lower frame, an upper frame vertically movably mounted on the lower frame, and a link mechanism for connecting the lower frame and the upper frame. The suspension unit also includes a magneto-spring unit for resiliently supporting the upper frame relative to the link mechanism, and a plurality of metal springs having opposite ends hooked on the upper frame and a portion of the link mechanism, respectively.
By this construction, the amount of motion of the magneto-spring unit is made smaller than that of the suspension unit, resulting in a relatively compact suspension unit having a large stroke.
Advantageously, the link mechanism includes an X-link having two links and the magneto-spring unit includes a stationary magnet unit and a movable magnet unit. The stationary magnet unit is mounted on the upper frame and the movable magnet unit is mounted on the X-link.
The suspension unit also includes an operating member for operating the plurality of metal springs to adjust a load applied to the upper frame. The link mechanism further includes a first torsion bar that produces a lifting force of the upper frame.
Advantageously, the suspension unit includes a second torsion bar mounted on the upper frame and a contact plate secured to a portion of the link mechanism, wherein when a displacement of the upper frame relative to the lower frame is greater than a predetermined value, the second torsion bar impinges on the contact plate to thereby produce a lifting force of the upper frame.
The plurality of elastic means such as the magneto-spring unit, the plurality of metal springs, and the first and second torsion bars make it possible to provide a suspension unit having a spring constant of substantially zero with respect to a displacement in a predetermined range.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objectives and features of the present invention will become more apparent from the following description of a preferred embodiment thereof with reference to the accompanying drawings, throughout which like parts are designated by like reference numerals, and wherein:
FIG. 1 is a perspective view of a suspension unit according to the present invention;
FIG. 2 is an exploded perspective view of the suspension unit of FIG. 1 ;
FIG. 3A is a schematic perspective view of a magneto-spring unit mounted in the suspension unit of FIG. 1 ;
FIG. 3B is a front view of the magneto-spring unit of FIG. 3A ;
FIG. 4 is a graph indicating the spring properties of a plurality of elastic means in the case where the load to be applied to the suspension unit of FIG. 1 has been adjusted to 70 kg;
FIG. 5 is a graph indicating the static characteristics of the suspension unit of FIG. 1 ; and
FIG. 6 is a graph indicating the dynamic characteristics of the suspension unit of FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
This application is based on an application No. 2003-152879 filed May 29, 2003 in Japan, the content of which is herein expressly incorporated by reference in its entirety.
Referring now to the drawings and particularly to FIGS. 1 and 2 , there is shown a suspension unit S embodying the present invention, which is used as a seat suspension, for example. The suspension unit S includes a generally rectangular lower frame 2 to be mounted on a vehicle floor and a generally rectangular upper frame 4 mounted on the lower frame 2 so as to be vertically movable relative thereto. A vehicle seat (not shown) is placed on the upper frame 4 .
An X-link having two links 6 , 8 rotatably connected to each other at intermediate portions thereof is disposed on each side of the suspension unit S. A front end of each link 6 is connected to a generally triangular oscillating plate 18 , while rear ends of both the links 6 are connected to each other via a cylindrical connecting shaft 12 . A front end of each link 8 is connected to a lower end of a generally rectangular oscillating plate 14 . Both the links 8 are connected to each other at respective positions apart a predetermined length rearwards from the front end thereof via a cylindrical connecting shaft 10 and at rear ends thereof via a cylindrical connecting shaft 16 . A bushing 15 rigidly secured to an upper portion of the oscillating plate 14 is rotatably connected to a front portion of the lower frame 2 via a pin 20 .
A bushing 19 rigidly secured to a lower portion of the oscillating plate 18 is rotatably connected to a front portion of the upper frame 4 via a pin 21 , and the oscillating plate 18 is joined to an end of a cylindrical connecting shaft 22 at a location forwards of the bushing 19 .
The rear connecting shaft 12 of the links 6 has a slip ring 24 mounted on each end thereof, on which a retainer ring 26 fixed to an inner surface of a side wall of the lower frame 2 is mounted for rotatably supporting the rear connecting shaft 12 . A torsion bar 28 having a square section is loosely inserted in the rear connecting shaft 12 . One end of the torsion bar 28 is secured to one end (rear end) of a lever 30 , the other end (front end) of which is secured to the side wall of the lower frame 2 . The other end of the torsion bar 28 is secured to an end of the rear connecting shaft 12 .
The rear connecting shaft 16 of the links 8 similarly has a slip ring 32 mounted on each end thereof, on which a retainer ring 34 fixed to an inner surface of a side wall of the upper frame 4 is mounted for rotatably supporting the rear connecting shaft 16 . A torsion bar 36 having a square section is loosely inserted in the rear connecting shaft 16 . One end of the torsion bar 36 is secured to one end (rear end) of a lever 38 , the other end (front end) of which is secured to the side wall of the upper frame 4 . The other end of the torsion bar 36 is secured to an end of the rear connecting shaft 16 .
A U-shaped bracket 40 is joined to the connecting shaft 22 and has an elongated opening 40 a defined in a front wall thereof. An operating shaft 44 having a knob 42 mounted on a front end thereof is loosely inserted in the elongated opening 40 a of the U-shaped bracket 40 , and a slip ring 46 is interposed between a rear end of the knob 42 and the front wall of the U-shaped bracket 40 . The operating shaft 44 has a male screw formed thereon, which is held in mesh with a female screw 48 a formed in a load adjusting shaft 48 that is located rearwards of the front wall of the U-shaped bracket 40 .
The load adjusting shaft 48 is rotatably connected to an upper portion of a spring-holding bracket 50 that is bent in the form of “U”, a lower portion of which is pivotally connected to a lower portion of the U-shaped bracket 40 . A spring-holding shaft 52 is mounted on a rear portion of the spring-holding bracket 50 , and a plurality of metal springs 54 are hooked at respective front ends on the spring-holding shaft 52 . The spring-holding bracket 50 has a load (weight) scale 56 mounted on a side portion thereof, and a pointer 58 confronting the load scale 56 is mounted on a side portion of the U-shaped bracket 40 .
The upper frame 4 has a rectangular opening 4 a defined therein and a recess 4 b formed at a location forwards of the rectangular opening 4 a . A rear spring-holding shaft 60 is received in the recess 4 b , and the plurality of metal springs 54 referred to above are hooked at respective rear ends on the rear spring-holding shaft 60 . A damper 62 is pivotally connected at a rear end (upper end) thereof to a lower surface of a rear portion of the upper frame 4 via a bracket (not shown), and is also pivotally connected at a front end (lower end) thereof to a bracket 64 that is joined to the lower frame 2 in proximity to a central portion thereof. Two torsion bars 66 bent in the form of “U” are disposed at a front portion of the upper frame 4 , and an inner end of each torsion bar 66 is secured to the upper frame 4 by means of a mounting member 68 , while an outer end of each torsion bar 66 is positioned above a contact plate 70 joined to the link 6 .
A magneto-spring unit 72 for resiliently supporting the upper frame 4 relative to the X-link 6 , 8 is disposed on each side of the damper 62 and includes a stationary magnet unit 74 and a movable magnet unit 76 .
As best shown in FIGS. 3A and 3B , the stationary magnet unit 74 includes a pair of upper permanent magnets 74 a and a pair of lower permanent magnets 74 b . The pair of upper magnets 74 a are spaced apart a predetermined distance with like magnetic poles opposed to each other. The same is true of the pair of lower magnets 74 b . The upper magnet 74 a and the lower magnet 74 b positioned on the same side are joined to each other such that unlike magnetic poles are oriented in the same direction (inwards or outwards). On the other hand, the movable magnet unit 76 has a permanent magnet positioned within an internal space in the stationary magnet unit 74 , and this permanent magnet has two magnetic poles formed on upper and lower portions thereof, respectively. The upper magnetic pole confronts the like magnetic poles of the pair of upper magnets 74 a of the stationary magnet unit 74 , and the lower magnetic pole similarly confronts the like magnetic poles of the pair of lower magnets 74 b of the stationary magnet unit 74 . As shown in FIG. 3B , a predetermined clearance is present between the stationary magnet unit 74 and the movable magnet unit 76 .
As shown in FIG. 2 , each stationary magnet unit 74 is secured to an inner surface of a side wall of a metal frame 78 mounted on the upper frame 4 . The movable magnet unit 76 disposed within the internal space in the stationary magnet unit 74 has front and rear mounting members 80 formed on opposite ends thereof, which are in turn supported by brackets 82 , 84 secured to the two links 6 , 8 of the X-link, respectively.
Belt holding members 86 , 88 made of a metal are joined to a rear portion of the lower frame 2 and a rear portion of the upper frame 4 , respectively, and opposite ends of a stroke restraining belt 90 are secured to the belt holding members 86 , 88 , respectively. A cushioning member 92 made of, for example, rubber is mounted on a rear portion of the lower frame 2 .
The suspension unit S of the above-described construction operates as follows.
When a user sits on a vehicle seat placed on the upper frame 4 , the upper frame 4 moves downwards according to the load (weight of the user). The downward movement of the upper frame 4 twists the lower torsion bar 28 and the upper torsion bar 36 to produce a lifting force of the upper frame 4 according to the length of travel of the upper frame 4 . The downward movement of the upper frame 4 also expands the plurality of metal springs 54 to produce a lifting force of the upper frame 4 according to the length of travel of the upper frame 4 . On the other hand, in an unloaded condition, the outer end of each torsion bar 66 mounted on the upper frame 4 is spaced apart from the contact plate 70 joined to the link 6 . When a load greater than a predetermined value is applied to the upper frame 4 to move the upper frame 4 downwards by a length of travel greater than a predetermined value (for example, 10 mm (see FIG. 4 )), the outer end of each torsion bar 66 impinges on the contact plate 70 , thereby gradually producing a lifting force of the upper frame 4 according to the length of travel of the upper frame 4 . The magneto-spring unit 72 presents a negative spring constant until a load greater than a predetermined value is applied to the upper frame 4 to move the upper frame 4 downwards by a length of travel greater than a predetermined value (for example, 25 mm (see FIG. 4 )), and when the upper frame 4 further moves downwards over the predetermined value, the magneto-spring unit 72 comes to present a positive spring constant and then gradually produces a lifting force of the upper frame 4 according to the length of travel of the upper frame 4 .
The graph of FIG. 4 indicates the spring properties of the lower torsion bar 28 , upper torsion bar 36 , metal springs 54 , U-shaped torsion bars 66 , and magneto-spring unit 72 in the case where the load has been adjusted to 70 kg by rotating the knob 42 .
The graph of FIG. 4 reveals that each of the lower torsion bar 28 and the upper torsion bar 36 has a linear spring constant irrespective of the displacement (stroke), while the U-shaped torsion bars 66 have a linear spring constant with respect to a displacement greater than a predetermined value. The graph of FIG. 4 also reveals that the metal springs 54 have a spring constant close to a linear one, but present a negative spring constant, although small, with respect to a load greater than a predetermined value (20 mm in the graph of FIG. 4 ), and that the magneto-spring unit 72 has a negative spring constant within a predetermined range (about ±20 mm in the graph of FIG. 4 ), but presents a positive spring constant outside this range.
The load adjustment that is carried out by rotating the knob 42 is explained hereinafter.
Because the knob 42 is mounted on the front end of the operating shaft 44 and the male screw formed on the operating shaft 44 is in mesh with the female screw 48 a formed in the load adjusting shaft 48 , the distance between the knob 42 and the load adjusting shaft 48 varies by rotating the knob 42 . When rotation of the knob 42 causes the load adjusting shaft 48 to approach the knob 42 , the spring-holding bracket 50 pivots forwards about a lower portion thereof at which the spring-holding bracket 50 is connected to the U-shaped bracket 40 . As a result, the plurality of metal springs 54 hooked on the front spring-holding shaft 52 expand, thereby increasing the lifting force of the upper frame 4 . In contrast, when rotation of the knob 42 causes the load adjusting shaft 48 to move away from the knob 42 , the spring-holding bracket 50 pivots rearwards about the lower portion thereof, and the plurality of metal springs 54 contract, thereby reducing the lifting force of the upper frame 4 .
The user can carry out the load adjustment referred to above while watching the load scale 56 to which the pointer 58 points, and the load can be adjusted in a range of, for example, 50 kg to 130 kg.
FIG. 5 is a graph indicating the static characteristics of the suspension unit S according to the present invention where the load is 50 kg, 70 kg, 90 kg, 110 kg, and 130 kg. The graph of FIG. 5 reveals that the suspension unit S has a spring constant of substantially zero or close to zero with respect to a displacement in a predetermined range.
FIG. 6 is a graph indicating the dynamic characteristics of the suspension unit S according to the present invention. The graph of FIG. 6 reveals that the vibration transmissibility at a resonance point is restrained to be low and that both the vibration characteristics at the resonance point and the impact absorption are good and the vibration characteristics in a high frequency region is also good.
When a vibration is inputted to a vehicle frame (not shown), the damper 62 operates to attenuate the vibration. When an impact force is inputted to cause the lower frame 2 to abnormally approach the upper frame 4 , the rear connecting shaft 16 impinges on the cushioning member 92 , thereby absorbing the impact (bottom-end shock). When the lower frame 2 comes to move abnormally away from the upper frame 4 , a tension is applied to the stroke restraining belt 90 , which in turn restrains the stroke of the upper frame 4 relative to the lower frame 2 .
It is to be noted that although the above-described embodiment has been explained taking the case of the seat suspension on which a vehicle seat is mounted, the present invention is not limited to only the seat suspension, but can be used as a vibration isolator, on which an apparatus other than the vehicle seat is placed, for attenuating a vibration from outside.
Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications otherwise depart from the spirit and scope of the present invention, they should be construed as being included therein.
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A suspension unit includes a lower frame and an upper frame vertically movably mounted on the lower frame via a link mechanism. The suspension unit also includes a magneto-spring unit for resiliently supporting the upper frame relative to the link mechanism. The amount of motion of the magneto-spring unit is smaller than that of the suspension unit, making it possible to provide a relatively compact suspension unit having a large stroke.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 13/999,431, filed Feb. 25, 2014, which claims the benefit of U.S. Provisional Application Ser. No. 61/853,787, filed Mar. 10, 2013.
TECHNICAL FIELD
[0002] This application relates to an optical spot array pitch compressor that compresses the optical spot array pitch of a passive wavelength division multiplexing (WDM) multiplexer (MUX) or demultiplexer (DeMUX) to match the pitch of an active laser diode (LD) array in a transmitter optical sub-assembly (TOSA) or photo diode (PD) array in a receiver optical sub-assembly (ROSA) and more specifically to an optical spot array pitch compressor that can compresses the optical spot array pitch with varying compression ratio.
BACKGROUND
[0003] Wavelength division multiplexing (WDM) is used to increase the communication bandwidth or the number of communication channels in optical communications. A number of optical signals carried by light having different wavelengths are input and propagating in a single optical fiber. A WDM multiplexer (MUX) is used to combine a number of optical signals carried by light having different wavelengths into a fiber. To detect each signal, the combined light exiting from the fiber is decomposed into its components having different wavelengths using a WDM demultiplexer (DeMUX). Each component corresponds to an optical signal. Typically, the optical signals decomposed by the DeMUX form an optical spot array on a cross-section plane. The pitch of the array is determined by the DeMUX. The optical signals are detected by an array of photo diodes (PD) in a receiver optical sub-assembly (ROSA).
[0004] Similarly, an array of laser diodes (LD) in a transmitter optical sub-assembly (TOSA) emits optical signals. Typically, the optical signals emitted by the LD array in the TOSA form an optical spot array on a cross-section plane. The optical signals are combined by a WDM MUX into an optical fiber. Accordingly, the optical spot array pitch of the passive WDM MUX or DeMUX must match the optical spot array pitch of the active LD or PD array.
[0005] The pitch of an active LD or PD array may be 3.05 mm, which is the diameter of the transistor outline (TO) can for packaging LD or PD. On the other hand, the pitch of an active LD or PD array may be 0.25 mm for an integrated LD or PD. The pitch of an active LD and PD array may be any number, which is determined by the manufacture of the device. Similarly, the pitch of a passive WDM MUX and DeMUX may be any number as well, which is determined by its manufacturer. Accordingly, an optical spot array pitch compressor to match the pitch of a passive WDM MUX or DeMUX with the pitch of an active LD or PD array is required. Furthermore, the optical spot array pitch compressor must be able to provide a varying compressor ratio. Especially, when the passive WDM MUX and DeMUX and the active LD and PD array are not made based on the same specification, or are made by different manufacturers. It is appreciated that it is almost impossible to compress the optical spot pitch of a passive WDM MUX or DeMUX to as small as 0.25 mm pitch using traditional free space optics.
[0006] U.S. Pat. No. 7,023,620 to Sandberg et al. discloses a device 100 to provide beam pitch compression using a group of mirror as shown in FIG. 1 . Four beams 102 , 104 , 106 , and 108 having wavelengths λ 1 , λ 2 , λ 3 , and λ 4 , respectively, are separated into a first group including beams 102 and 104 , and a second group including beams 106 and 108 . The first group including beams 102 and 104 is reflected 90° by a first mirror 110 . The second group including beams 106 and 108 is reflected 90° by a second mirror 112 . Second mirror 112 has a hole or window to allow beam 104 passing through. If there are more than four beams, second mirror 112 must have a periodical structure mirror-window-mirror-window to reflect beams of the second group and to transmit beams of the first group. Device 100 will change the order of beams 102 , 104 , 106 , and 108 to a new order of beams 102 , 106 , 104 , and 108 . The special structure of second mirror 112 will increase the cost. Device 100 will have a fix compression ratio instead of a varying compression ratio.
[0007] U.S. Pat. No. 4,627,690 to Fantone discloses an anamorphic prism 200 for beam compression as shown in FIG. 2 . An incident beam 202 enters anamorphic prism 200 normally from a right angle surface 204 . After having two total internal reflections (TIR) at an inclined surfaces 206 and a flat surface 208 , incident beam 202 is refracted from inclined surface 206 to the air becoming an output beam 210 . Incident beam 202 originally has a beam diameter Win. Output beam 210 has a compressed beam diameter Wout. The compression ratio is Win/Wout. Anamorphic prism 200 requires the following conditions be satisfied.
[0000]
n
=
cos
α
cos
3
α
,
Equation
(
1
)
η
=
W
in
W
out
=
2
+
1
n
,
Equation
(
2
)
[0000] where n is the refractive index of anamorphic prism 200 , a is an apex angle 212 of anamorphic prism 200 , and η is the compression ratio.
[0008] Apex angle 212 , a, is determined in a range of 17° to 19° by the refractive index n. Compression ratio η, which is in a range of 2 to 3, is also determined by the refractive index n. Due to the small apex angle (17°˜19°), the prism must have a long length L 214 to fully transmit the beam through the prism. Furthermore, inclined surface 206 includes an area of TIR 216 , which is not coated, and an area of refraction 218 , which is anti-reflection (AR) coated. To separate two areas 216 and 218 in an AR coating process, the prism may not be small. Anamorphic prism 200 has a fix compression ratio instead of a varying compression ratio.
[0009] Accordingly, an optical spot array pitch compressor to match the pitch of a WDM MUX or DeMUX with the pitch of a LD or PD array, which is simple, small, low cost, and capable of providing a varying compression ratio, is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Non-limiting and non-exhaustive embodiments of the present application are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
[0011] FIG. 1 shows a beam pitch compression using a group of mirror.
[0012] FIG. 2 shows a beam compression using an anamorphic prism.
[0013] FIG. 3 shows a typical 4-channel ROSA including a zigzag WDM DeMUX.
[0014] FIG. 4 shows an embodiment of a ROSA including an optical wedge between passive and active components.
[0015] FIG. 5 shows an optical wedge having refractive index n, apex angle α, and output angle θ.
[0016] FIG. 6 shows plots of compression ratio as function of apex angle α for refractive index n=1.5 (broken line) and n=1.75 (solid line).
[0017] FIG. 7 shows light transmitting an optical wedge having incident angle β and output angle θ.
[0018] FIG. 8 shows a plot of output angle θ as function of incident angle β for refractive index n=1.748 and apex angle a=31.1°.
[0019] FIG. 9 shows a plot of compression ratio η as function of incident angle β.
[0020] FIG. 10 shows an embodiment of a ROSA including two optical wedges between passive and active components.
[0021] FIG. 11 shows an embodiment of a ROSA including a grating between passive and active components.
[0022] Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present application.
DETAILED DESCRIPTION
[0023] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present application. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present application.
[0024] Reference throughout this specification to “one embodiment” 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 application. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and/or sub-combinations in one or more embodiments.
[0025] A free space optical sub-assembly (OSA) integrates a passive component such as a WDM MUX or DeMUX and an active component such as a LD or PD array. A typical WDM MUX or DeMUX comprising thin film filters (TFF) is based on a zigzag optical path design. U.S. Pat. No. 6,201,908 to Grann and U.S. Pat. No. 6,769,816 to Capewell et al. show examples of a zigzag WDM DeMUX. FIG. 3 shows a typical 4-channel ROSA 300 including a zigzag WDM DeMUX.
[0026] ROSA 300 includes a passive WDM DeMUX 302 and an active PD array 304 . Passive WDM DeMUX 302 includes four TFFs, 310 , 312 , 314 , and 316 , and three mirrors, 320 , 322 , and 324 . Active PD array 304 includes four lenses 350 , 352 , 354 , and 356 , and four PDs, 360 , 362 , 364 , and 366 . A wavelength multiplexed beam 306 having λ 1 , λ 2 , λ 3 , and λ 4 wavelengths is output from an optical fiber and enters into ROSA 300 through a common port 308 . Beam 306 is directed to TFF 310 . Light having wavelength λ 1 is transmitted through TFF 310 , focused by lens 350 and detected by PD 360 . The rest of beam 306 is reflected by TFF 310 toward mirror 320 . Beam 306 is directed to TFF 312 by mirror 320 . Light having wavelength λ 2 is transmitted through TFF 312 , focused by lens 352 and detected by PD 362 . The rest of beam 306 is reflected by TFF 312 toward mirror 322 . Beam 306 is directed to TFF 314 by mirror 322 . Light having wavelength λ 3 is transmitted through TFF 314 , focused by lens 354 and detected by PD 364 . The rest of beam 306 is reflected by TFF 314 toward mirror 324 . Beam 306 is directed to TFF 316 by minor 324 . Light having wavelength λ 4 is transmitted through TFF 316 , focused by lens 356 and detected by PD 366 .
[0027] It is appreciated that ROSA and TOSA, in principle, have the same structure, but the optical path is reversed. Accordingly, FIG. 3 can be seen as a TOSA, in which the PD array is replaced with a LD array, and the optical path is reversed. Instead of a PD detecting light beam, a LD is emitting a light beam. Minor modification may further be made. For example, in a TOSA, TFF 316 or the last TFF may be removed. An optical isolator may be disposed at common port 308 . In the disclosure, a ROSA is described in general, one skilled in the art would understand that the same principle applies to a TOSA as well, by reversing the optical path and replacing the PD array with a LD array.
[0028] Recently, the pitch of the active LD or PD array decreases while the pitch of optical spot array generated by a traditional WDM MUX or DeMUX comprising TFFs based on a zigzag optical path design does not significantly decrease because it is difficult to reduce the size of the traditional passive WDM MUX or DeMUX. The typical numbers for pitch of the active LD or PD array currently include 0.25, 0.5, 0.75, 1.5 and 3.05 mm. The TO can provide a pitch of 3.05 mm. However the integrated technique provides a pitch of 0.25 mm. Accordingly, a solution is sought to solve how to couple the optical spot array from a passive WDM MUX or DeMUX to an active LD or PD array.
[0029] FIG. 4 is an exemplary embodiment of an ROSA 400 including an optical wedge 402 between passive and active components, according to the present application. FIG. 4 is essentially the same as FIG. 3 . The difference between FIG. 4 and FIG. 3 is optical wedge 402 disposed between passive WDM DeMUX 302 and active PD array 404 . A light beam 410 having wavelength λ 1 is bent by optical wedge 402 becoming a light beam 420 . A light beam 412 having wavelength λ 2 is bent by optical wedge 402 becoming a light beam 422 . A light beam 414 having wavelength λ 3 is bent by optical wedge 402 becoming a light beam 424 . A light beam 416 having wavelength λ 4 is bent by optical wedge 402 becoming a light beam 426 . The pitch of optical spot array of passive WDM DeMUX 302 , which is the separation between beams 410 and 412 , beams 412 and 414 , and beams 414 and 416 , is compressed by optical wedge 402 . In other words, the separation between beams 420 and 422 , beams 422 and 424 , and beams 424 and 426 is smaller than the separation beams 410 and 412 , beams 412 and 414 , and beams 414 and 416 . Thus, PD array 404 having smaller pitch can be used.
[0030] It is appreciated that the number of light beams is not limited to four. Any number is possible. Accordingly, the number of mirrors and TFFs may be any number as well.
[0031] A compression ratio η is a function of refractive index n, apex angle a, and output angle θ, of optical wedge 402 . FIG. 5 shows optical wedge 402 having refractive index n, apex angle a, and output angle θ, according to the present application. Optical wedge 402 comprises a right angle surface 502 , an inclined surface 504 , and a flat surface 506 . Incident beams 508 and 510 are incident normally on right angle surface 502 , and transmitted through optical wedge 402 , before they are bent becoming output beams 512 and 514 , respectively, having output angle θ.
[0032] Since the incident beams are incident normally, compression ratio η, which is Win/Wout, is a function of refractive index n and apex angle a of optical wedge 402 , as shown in FIG. 5 . Win is a separation of two adjacent incident beams, and Wout is a separation of two adjacent output beams. Plots of compression ratio as function of apex angle a for refractive index n=1.5 (broken line) and n=1.75 (solid line) are shown in FIG. 6 , according to the present application. The compression ratio η as function of apex angle a and refractive index n is given in Equation 3.
[0000]
η
=
cos
α
cos
[
sin
-
1
(
n
sin
α
)
]
,
Equation
(
3
)
[0033] Increase in an incident angle 702 , β, will change an output angle 704 , θ, as shown in FIG. 7 , according to the present application. A plot showing the relationship of output angle θ and incident angle β for refractive index n=1.748 and apex angle a=31.1° is given in FIG. 8 , according to the present application. FIG. 8 shows that increase in incident angle β will result in decrease in output angle θ. The output angle θ as function of input angle β, apex angle α and refractive index n is given in Equation 4.
[0000]
θ
=
sin
-
1
{
n
sin
[
α
-
sin
-
1
(
sin
β
n
)
]
}
,
Equation
(
4
)
[0034] FIG. 9 shows a plot of compression ratio η as function of incident angle β, according to the present application. The plot in FIG. 9 is calculated using data of FIG. 8 . FIG. 9 shows that for the incident angle range of β=−2° to β=1.8°, compression ratio is decreasing in the range η=2.4 to η=1.8. The compression ratio η as function of input angle β, apex angle α and refractive index n is given in Equation 5.
[0000]
η
=
cos
[
α
-
sin
-
1
(
sin
β
n
)
]
cos
[
sin
-
1
(
sin
β
n
)
]
×
cos
β
cos
{
sin
-
1
[
n
sin
(
α
-
sin
-
1
(
sin
β
n
)
)
]
}
,
Equation
(
5
)
[0035] Accordingly, after a single optical wedge is made and disposed between the passive WDM DeMUX and the active PD array, the compression ratio can be adjusted by changing the incident angle as shown in Equation (5). A beam incident to the right angle surface of an optical wedge is refracted into the optical wedge. The beam is transmitted in the optical wedge and arriving at the inclined surface of the optical wedge, and is refracted to the air. Thus, no TIR occurs in the optical wedge. As mentioned previously, it is appreciated that the embodiment and the calculation may be applied to a TOSA comprising a passive WDM MUX and an active LD array by reversing the light path.
[0036] FIG. 10 shows that a second optical wedge 1002 may be included in an exemplary embodiment 1000 , according to the present application. FIG. 10 is essentially the same as FIG. 4 . The difference between FIG. 10 and FIG. 4 includes that second optical wedge 1002 is added between a first optical wedge 402 and PD array 404 . Thus, embodiment 1000 of FIG. 10 provides a two level compression. The compression ratio of the two level compression of FIG. 10 is higher than the compression ratio of FIG. 4 . Second optical wedge 1002 also compensates for some second order effects generated by first optical wedge 402 , because the directions of optical wedge 1002 and optical wedge 402 are opposite. The compression ratio can be adjusted by changing the incident angle as described previously. A plurality of optical wedges may be included in an embodiment of the present application to further increase the compression ratio.
[0037] FIG. 11 shows an exemplary embodiment 1100 replacing optical wedge 402 with a grating 1102 , according to the present application. In FIG. 4 , incident beams 410 - 416 are refracted by optical wedge 402 becoming bent output beams 420 - 426 . Incident beams 410 - 416 may be diffracted by grating 1102 becoming bent output beams 420 - 426 , as shown in FIG. 11 . The compression ratio can be adjusted by changing the incident angle as well.
[0038] An apparatus is disclosed that comprises a passive WDM DeMUX or a passive WDM MUX, an active PD array or an active LD array, and a compressing device disposed between the passive WDM DeMUX or the passive WDM MUX and the active PD array or the active LD array. The compressing device changes the optical spot pitch of the passive WDM DeMUX or the passive WDM MUX to match the pitch of the active PD array or the active LD array. The compressing device may be a single optical wedge, a first and a second wedges, plurality of optical wedges, or a grating. A compression ratio can be adjusted by changing the incident angle of the incident beam to the compressing device.
[0039] While the present application has been described herein with respect to the exemplary embodiments and the best mode for practicing the application, it will be apparent to one of ordinary skill in the art that many modifications, improvements and sub-combinations of the various embodiments, adaptations and variations can be made to the application without departing from the spirit and scope thereof. For the disclosed methods, the steps need not necessarily be performed sequentially.
[0040] The terms used in the following claims should not be construed to limit the application to the specific embodiments disclosed in the specification and the claims. Rather, the scope is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation. The present specification and figures are accordingly to be regarded as illustrative rather than restrictive.
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An apparatus including a passive wavelength division multiplexing (WDM) demultiplexer (DeMUX) or a passive WDM multiplexer (MUX), an active photo diode (PD) array or an active laser diode (LD) array, and a compressing device disposed between the passive WDM DeMUX or the passive WDM MUX and the active PD array or the active LD array. The compressing device changes the optical spot pitch of the passive WDM DeMUX or the passive WDM MUX o match the pitch of the active PD array or the active LD array. A compression ratio can be adjusted by changing the incident angle of the incident beam to the compressing device.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Ser. No. 60/945,487, filed Jun. 21, 2007, the disclosure of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to certain spirocyclic compounds that are inhibitors of 11-β hydroxyl steroid dehydrogenase type 1 (11βHSD1), compositions containing the same, and methods of using the same for the treatment of diabetes, obesity and other diseases.
BACKGROUND OF THE INVENTION
The importance of the hypothalamic-pituitary-adrenal (HPA) axis in controlling glucocorticoid excursions is evident from the fact that disruption of homeostasis in the HPA axis by either excess or deficient secretion or action results in Cushing's syndrome or Addison's disease, respectively (Miller and Chrousos (2001) Endocrinology and Metabolism, eds. Felig and Frohman (McGraw-Hill, New York), 4 th Ed.: 387-524). Patients with Cushing's syndrome (a rare disease characterized by systemic glucocorticoid excess originating from the adrenal or pituitary tumors) or receiving glucocorticoid therapy develop reversible visceral fat obesity. Interestingly, the phenotype of Cushing's syndrome patients closely resembles that of Reaven's metabolic syndrome (also known as Syndrome X or insulin resistance syndrome) the symptoms of which include visceral obesity, glucose intolerance, insulin resistance, hypertension, type 2 diabetes and hyperlipidemia (Reaven (1993) Ann. Rev. Med. 44: 121-131). However, the role of glucocorticoids in prevalent forms of human obesity has remained obscure because circulating glucocorticoid concentrations are not elevated in the majority of metabolic syndrome patients. In fact, glucocorticoid action on target tissue depends not only on circulating levels but also on intracellular concentration, locally enhanced action of glucocorticoids in adipose tissue and skeletal muscle has been demonstrated in metabolic syndrome. Evidence has accumulated that enzyme activity of 11βHSD1, which regenerates active glucocorticoids from inactive forms and plays a central role in regulating intracellular glucocorticoid concentration, is commonly elevated in fat depots from obese individuals. This suggests a role for local glucocorticoid reactivation in obesity and metabolic syndrome.
Given the ability of 11βHSD1 to regenerate cortisol from inert circulating cortisone, considerable attention has been given to its role in the amplification of glucocorticoid function. 11βHSD1 is expressed in many key GR-rich tissues, including tissues of considerable metabolic importance such as liver, adipose, and skeletal muscle, and, as such, has been postulated to aid in the tissue-specific potentiation of glucocorticoid-mediated antagonism of insulin function. Considering a) the phenotypic similarity between glucocorticoid excess (Cushing's syndrome) and the metabolic syndrome with normal circulating glucocorticoids in the latter, as well as b) the ability of 11βHSD1 to generate active cortisol from inactive cortisone in a tissue-specific manner, it has been suggested that central obesity and the associated metabolic complications in syndrome X result from increased activity of 11βHSD1 within adipose tissue, resulting in ‘Cushing's disease of the omentum’ (Bujalska et al. (1997) Lancet 349: 1210-1213). Indeed, 11βHSD1 has been shown to be upregulated in adipose tissue of obese rodents and humans (Livingstone et al. (2000) Endocrinology 131: 560-563; Rask et al. (2001) J. Clin. Endocrinol. Metab. 86: 1418-1421; Lindsay et al. (2003) J. Clin. Endocrinol. Metab. 88: 2738-2744; Wake et al. (2003) J. Clin. Endocrinol. Metab. 88: 3983-3988).
Additional support for this notion has come from studies in mouse transgenic models. Adipose-specific overexpression of 11βHSD1 under the control of the aP2 promoter in mouse produces a phenotype remarkably reminiscent of human metabolic syndrome (Masuzaki et al. (2001) Science 294: 2166-2170; Masuzaki et al. (2003) J. Clinical Invest. 112: 83-90). Importantly, this phenotype occurs without an increase in total circulating corticosterone, but rather is driven by a local production of corticosterone within the adipose depots. The increased activity of 11βHSD1 in these mice (2-3 fold) is very similar to that observed in human obesity (Rask et al. (2001) J. Clin. Endocrinol. Metab. 86: 1418-1421). This suggests that local 11βHSD1-mediated conversion of inert glucocorticoid to active glucocorticoid can have profound influences whole body insulin sensitivity.
Based on this data, it would be predicted that the loss of 11βHSD1 would lead to an increase in insulin sensitivity and glucose tolerance due to a tissue-specific deficiency in active glucocorticoid levels. This is, in fact, the case as shown in studies with 11βHSD1-deficient mice produced by homologous recombination (Kotelevstev et al. (1997) Proc. Natl. Acad. Sci. 94: 14924-14929; Morton et al. (2001) J. Biol. Chem. 276: 41293-41300; Morton et al. (2004) Diabetes 53: 931-938). These mice are completely devoid of 11-keto reductase activity, confirming that 11βHSD1 encodes the only activity capable of generating active corticosterone from inert 11-dehydrocorticosterone. 11βHSD1-deficient mice are resistant to diet- and stress-induced hyperglycemia, exhibit attenuated induction of hepatic gluconeogenic enzymes (PEPCK, G6P), show increased insulin sensitivity within adipose, and have an improved lipid profile (decreased triglycerides and increased cardio-protective HDL). Additionally, these animals show resistance to high fat diet-induced obesity. Taken together, these transgenic mouse studies confirm a role for local reactivation of glucocorticoids in controlling hepatic and peripheral insulin sensitivity, and suggest that inhibition of 11βHSD1 activity may prove beneficial in treating a number of glucocorticoid-related disorders, including obesity, insulin resistance, hyperglycemia, and hyperlipidemia.
Data in support of this hypothesis has been published. Recently, it was reported that 11βHSD1 plays a role in the pathogenesis of central obesity and the appearance of the metabolic syndrome in humans. Increased expression of the 11βHSD1 gene is associated with metabolic abnormalities in obese women and that increased expression of this gene is suspected to contribute to the increased local conversion of cortisone to cortisol in adipose tissue of obese individuals (Engeli, et al., (2004) Obes. Res. 12: 9-17).
A new class of 11βHSD1 inhibitors, the arylsulfonamidothiazoles, was shown to improve hepatic insulin sensitivity and reduce blood glucose levels in hyperglycemic strains of mice (Barf et al. (2002) J. Med. Chem. 45: 3813-3815; Alberts et al. Endocrinology (2003) 144: 4755-4762). Furthermore, it was recently reported that selective inhibitors of 11βHSD1 can ameliorate severe hyperglycemia in genetically diabetic obese mice. Thus, 11βHSD1 is a promising pharmaceutical target for the treatment of the Metabolic Syndrome (Masuzaki, et al., (2003) Curr. Drug Targets Immune Endocr. Metabol. Disord. 3: 255-62).
A. Obesity and Metabolic Syndrome
As described above, multiple lines of evidence suggest that inhibition of 11βHSD1 activity can be effective in combating obesity and/or aspects of the metabolic syndrome cluster, including glucose intolerance, insulin resistance, hyperglycemia, hypertension, and/or hyperlipidemia. Glucocorticoids are known antagonists of insulin action, and reductions in local glucocorticoid levels by inhibition of intracellular cortisone to cortisol conversion should increase hepatic and/or peripheral insulin sensitivity and potentially reduce visceral adiposity. As described above, 11βHSD1 knockout mice are resistant to hyperglycemia, exhibit attenuated induction of key hepatic gluconeogenic enzymes, show markedly increased insulin sensitivity within adipose, and have an improved lipid profile. Additionally, these animals show resistance to high fat diet-induced obesity (Kotelevstev et al. (1997) Proc. Natl. Acad. Sci. 94: 14924-14929; Morton et al. (2001) J. Biol. Chem. 276: 41293-41300; Morton et al. (2004) Diabetes 53: 931-938). Thus, inhibition of 11βHSD1 is predicted to have multiple beneficial effects in the liver, adipose, and/or skeletal muscle, particularly related to alleviation of component(s) of the metabolic syndrome and/or obesity.
B. Pancreatic Function
Glucocorticoids are known to inhibit the glucose-stimulated secretion of insulin from pancreatic beta-cells (Billaudel and Sutter (1979) Horm. Metab. Res. 11: 555-560). In both Cushing's syndrome and diabetic Zucker fa/fa rats, glucose-stimulated insulin secretion is markedly reduced (Ogawa et al. (1992) J. Clin. Invest. 90: 497-504). 11βHSD1 mRNA and activity has been reported in the pancreatic islet cells of ob/ob mice and inhibition of this activity with carbenoxolone, an 11βHSD1 inhibitor, improves glucose-stimulated insulin release (Davani et al. (2000) J. Biol. Chem. 275: 34841-34844). Thus, inhibition of 11βHSD1 is predicted to have beneficial effects on the pancreas, including the enhancement of glucose-stimulated insulin release.
C. Cognition and Dementia
Mild cognitive impairment is a common feature of aging that may be ultimately related to the progression of dementia. In both aged animals and humans, inter-individual differences in general cognitive function have been linked to variability in the long-term exposure to glucocorticoids (Lupien et al. (1998) Nat. Neurosci. 1: 69-73). Further, dysregulation of the HPA axis resulting in chronic exposure to glucocorticoid excess in certain brain subregions has been proposed to contribute to the decline of cognitive function (McEwen and Sapolsky (1995) Curr. Opin. Neurobiol. 5: 205-216). 11βHSD1 is abundant in the brain, and is expressed in multiple subregions including the hippocampus, frontal cortex, and cerebellum (Sandeep et al. (2004) Proc. Natl. Acad. Sci. Early Edition: 1-6). Treatment of primary hippocampal cells with the 11βHSD1 inhibitor carbenoxolone protects the cells from glucocorticoid-mediated exacerbation of excitatory amino acid neurotoxicity (Rajan et al. (1996) J. Neurosci. 16: 65-70). Additionally, 11βHSD1-deficient mice are protected from glucocorticoid-associated hippocampal dysfunction that is associated with aging (Yau et al. (2001) Proc. Natl. Acad. Sci. 98: 4716-4721). In two randomized, double-blind, placebo-controlled crossover studies, administration of carbenoxolone improved verbal fluency and verbal memory (Sandeep et al. (2004) Proc. Natl. Acad. Sci. Early Edition: 1-6). Thus, inhibition of 11βHSD1 is predicted to reduce exposure to glucocorticoids in the brain and protect against deleterious glucocorticoid effects on neuronal function, including cognitive impairment, dementia, and/or depression.
D. Intra-Ocular Pressure
Glucocorticoids can be used topically and systemically for a wide range of conditions in clinical ophthalmology. One particular complication with these treatment regimens is corticosteroid-induced glaucoma. This pathology is characterized by a significant increase in intra-ocular pressure (IOP). In its most advanced and untreated form, IOP can lead to partial visual field loss and eventually blindness. IOP is produced by the relationship between aqueous humour production and drainage. Aqueous humour production occurs in the non-pigmented epithelial cells (NPE) and its drainage is through the cells of the trabecular meshwork. 11βHSD1 has been localized to NPE cells (Stokes et al. (2000) Invest. Ophthalmol. Vis. Sci. 41: 1629-1683; Rauz et al. (2001) Invest. Ophthalmol. Vis. Sci. 42: 2037-2042) and its function is likely relevant to the amplification of glucocorticoid activity within these cells. This notion has been confirmed by the observation that free cortisol concentration greatly exceeds that of cortisone in the aqueous humour (14:1 ratio). The functional significance of 11βHSD1 in the eye has been evaluated using the inhibitor carbenoxolone in healthy volunteers (Rauz et al. (2001) Invest. Ophthalmol. Vis. Sci. 42: 2037-2042). After seven days of carbenoxolone treatment, IOP was reduced by 18%. Thus, inhibition of 11βHSD1 in the eye is predicted to reduce local glucocorticoid concentrations and IOP, producing beneficial effects in the management of glaucoma and other visual disorders.
E. Hypertension
Adipocyte-derived hypertensive substances such as leptin and angiotensinogen have been proposed to be involved in the pathogenesis of obesity-related hypertension (Matsuzawa et al. (1999) Ann. N.Y. Acad. Sci. 892: 146-154; Wajchenberg (2000) Endocr. Rev. 21: 697-738). Leptin, which is secreted in excess in aP2-11βHSD1 transgenic mice (Masuzaki et al. (2003) J. Clinical Invest. 112: 83-90), can activate various sympathetic nervous system pathways, including those that regulate blood pressure (Matsuzawa et al. (1999) Ann. N.Y. Acad. Sci. 892: 146-154). Additionally, the renin-angiotensin system (RAS) has been shown to be a major determinant of blood pressure (Walker et al. (1979) Hypertension 1: 287-291). Angiotensinogen, which is produced in liver and adipose tissue, is the key substrate for renin and drives RAS activation. Plasma angiotensinogen levels are markedly elevated in aP2-11βHSD1 transgenic mice, as are angiotensin II and aldosterone (Masuzaki et al. (2003) J. Clinical Invest. 112: 83-90). These forces likely drive the elevated blood pressure observed in aP2-11βHSD1 transgenic mice. Treatment of these mice with low doses of an angiotensin II receptor antagonist abolishes this hypertension (Masuzaki et al. (2003) J. Clinical Invest. 112: 83-90). This data illustrates the importance of local glucocorticoid reactivation in adipose tissue and liver, and suggests that hypertension may be caused or exacerbated by 11βHSD1 activity. Thus, inhibition of 11βHSD1 and reduction in adipose and/or hepatic glucocorticoid levels is predicted to have beneficial effects on hypertension and hypertension-related cardiovascular disorders.
F. Bone Disease
Glucocorticoids can have adverse effects on skeletal tissues. Continued exposure to even moderate glucocorticoid doses can result in osteoporosis (Cannalis (1996) J. Clin. Endocrinol. Metab. 81: 3441-3447) and increased risk for fractures. Experiments in vitro confirm the deleterious effects of glucocorticoids on both bone-resorbing cells (also known as osteoclasts) and bone forming cells (osteoblasts). 11βHSD1 has been shown to be present in cultures of human primary osteoblasts as well as cells from adult bone, likely a mixture of osteoclasts and osteoblasts (Cooper et al. (2000) Bone 27: 375-381), and the 11βHSD1 inhibitor carbenoxolone has been shown to attenuate the negative effects of glucocorticoids on bone nodule formation (Bellows et al. (1998) Bone 23: 119-125). Thus, inhibition of 11βHSD1 is predicted to decrease the local glucocorticoid concentration within osteoblasts and osteoclasts, producing beneficial effects in various forms of bone disease, including osteoporosis.
Small molecule inhibitors of 11βHSD1 are currently being developed to treat or prevent 11βHSD1-related diseases such as those described above. For example, certain amide-based inhibitors are reported in WO 2004/089470, WO 2004/089896, WO 2004/056745, and WO 2004/065351. Additional small molecule inhibitors of 11βHSD1 are reported in US 2005/0282858, US 2006/0009471, US 2005/0288338, US 2006/0009491, US 2006/0004049, US 2005/0288317, US 2005/0288329, US 2006/0122197, US 2006/0116382, and US 2006/0122210. 11) INCY0035 (US 2007/0066584)
Antagonists of 11βHSD1 have been evaluated in human clinical trials (Kurukulasuriya, et al., (2003) Curr. Med. Chem. 10: 123-53).
In light of the experimental data indicating a role for 11βHSD1 in glucocorticoid-related disorders, metabolic syndrome, hypertension, obesity, insulin resistance, hyperglycemia, hyperlipidemia, type 2 diabetes, androgen excess (hirsutism, menstrual irregularity, hyperandrogenism) and polycystic ovary syndrome (PCOS), therapeutic agents aimed at augmentation or suppression of these metabolic pathways, by modulating glucocorticoid signal transduction at the level of 11βHSD1 are desirable.
As evidenced herein, there is a continuing need for new and improved drugs that target 11βHSD1. The compounds, compositions and methods described herein help meet this and other needs.
SUMMARY OF THE INVENTION
The present invention provides, inter alia, inhibitors of 11βHSD1 having Formula I:
or pharmaceutically acceptable salts thereof, wherein the variables are defined below.
The present invention further provides compositions comprising a compound of Formula I, or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable carrier.
The present invention further provides methods of inhibiting 11βHSD1 by contacting the 11βHSD1 with a compound of Formula I, or a pharmaceutically acceptable salt thereof.
The present invention further provides methods of inhibiting activity of 11βHSD1 comprising contacting the 11βHSD1 with a compound of Formula I, or a pharmaceutically acceptable salt thereof.
The present invention further provides methods of inhibiting the conversion of cortisone to cortisol in a cell comprising contacting the cell with a compound of Formula I, or a pharmaceutically acceptable salt thereof.
The present invention further provides methods of inhibiting the production of cortisol in a cell comprising contacting the cell with a compound of Formula I, or a pharmaceutically acceptable salt thereof.
The present invention further provides methods of treating various diseases including any one of the following disorders, or any combination of two or more of the following disorders: obesity; diabetes; glucose intolerance; insulin resistance; hyperglycemia; hypertension; hyperlipidemia; cognitive impairment; depression; dementia; glaucoma; cardiovascular disorders; osteoporosis; inflammation; metabolic syndrome; androgen excess; or polycystic ovary syndrome (PCOS) in a patient comprising administering to the patient a therapeutically effective amount of a compound of Formula I, or a pharmaceutically acceptable salt thereof.
DETAILED DESCRIPTION
The present invention provides, inter alia, inhibitors of 11βHSD1 having Formula I:
or pharmaceutically acceptable salts thereof, wherein:
R 1 is F, Cl, Br, or I; and
R 2 and R 3 are independently selected from H, C 1-6 alkyl, and C 3-6 cycloalkyl.
In some embodiments:
R 1 is F and Cl; and R 2 and R 3 are independently selected from H and C 1-4 alkyl.
In some embodiments, R 1 is F or Cl.
In some embodiments, R 1 is F.
In some embodiments, R 1 is Cl.
In some embodiments, R 2 and R 3 are independently selected from H, methyl, and ethyl.
In some embodiments, at least one of R 2 and R 3 is other than H.
In some embodiments, the compounds of the invention have Formula II:
At various places in the present specification, substituents of compounds of the invention are disclosed in groups or in ranges. It is specifically intended that the invention include each and every individual subcombination of the members of such groups and ranges. For example, the term “C 1-6 alkyl” is specifically intended to individually disclose methyl, ethyl, C 3 alkyl, C 4 alkyl, C 5 alkyl, and C 6 alkyl.
It is further appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, can also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, can also be provided separately or in any suitable subcombination.
As used herein, the term “alkyl” is meant to refer to a saturated hydrocarbon group which is straight-chained or branched. Example alkyl groups include methyl (Me), ethyl (Et), propyl (e.g., n-propyl and isopropyl), butyl (e.g., n-butyl, isobutyl, t-butyl), pentyl (e.g., n-pentyl, isopentyl, neopentyl), and the like.
As used herein, “cycloalkyl” refers to non-aromatic 3-7 membered carbocycles including, for example, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.
The compounds described herein are asymmetric (e.g., having one or more stereocenters). All stereoisomers, such as enantiomers, are intended unless otherwise indicated. Compounds of the present invention that contain asymmetrically substituted carbon atoms can be isolated in optically active or racemic forms. Methods on how to prepare optically active forms from optically active starting materials are known in the art, such as by resolution of racemic mixtures or by stereoselective synthesis. Cis and trans isomers of the compounds of the present invention are described and may be isolated as a mixture of isomers or as separated isomeric forms.
Compounds of the invention can also include tautomeric forms. Tautomeric forms result from the swapping of a single bond with an adjacent double bond together with the concomitant migration of a proton. Tautomeric forms include prototropic tautomers which are isomeric protonation states having the same empirical formula and total charge. Example prototropic tautomers include ketone—enol pairs, amide—imidic acid pairs, lactam—lactim pairs, amide—imidic acid pairs, enamine—imine pairs, and annular forms where a proton can occupy two or more positions of a heterocyclic system, for example, 1H- and 3H-imidazole, 1H-, 2H- and 4H-1,2,4-triazole, 1H- and 2H-isoindole, and 1H- and 2H-pyrazole. Tautomeric forms can be in equilibrium or sterically locked into one form by appropriate substitution.
Compounds of the invention can also include all isotopes of atoms occurring in the intermediates or final compounds. Isotopes include those atoms having the same atomic number but different mass numbers. For example, isotopes of hydrogen include tritium and deuterium.
All compounds, and pharmaceutically acceptable salts thereof, may be obtained in various solid forms, including solvated or hydrated forms. In some embodiments, the solid form is a crystalline form. Methods for preparing and discovering different solid forms are routine in the art and include, for example, X-ray powder diffraction, differential scanning calorimetry, thermogravimetric analysis, dynamic vapor sorption, FT-IR, Raman scattering methods, solid state NMR, Karl-Fischer titration, etc.
In some embodiments, the compounds of the invention, and salts thereof, are substantially isolated. By “substantially isolated” is meant that the compound is at least partially or substantially separated from the environment in which it was formed or detected. Partial separation can include, for example, a composition enriched in the compound of the invention. Substantial separation can include compositions containing at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 97%, or at least about 99% by weight of the compound of the invention, or salt thereof. Methods for isolating compounds and their salts are routine in the art.
The present invention also includes pharmaceutically acceptable salts of the compounds described herein. As used herein, “pharmaceutically acceptable salts” refers to derivatives of the disclosed compounds wherein the parent compound is modified by converting an existing acid or base moiety to its salt form. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts of the present invention include the conventional non-toxic salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in Remington's Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., 1985, p. 1418 and Journal of Pharmaceutical Science, 66, 2 (1977), each of which is incorporated herein by reference in its entirety.
The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.
Compounds of the invention can modulate activity of 11βHSD1. The term “modulate” is meant to refer to an ability to increase or decrease activity of an enzyme or receptor. Accordingly, compounds of the invention can be used in methods of modulating 11βHSD1 by contacting the enzyme or receptor with any one or more of the compounds or compositions described herein. In some embodiments, compounds of the present invention can act as inhibitors of 11βHSD1. In further embodiments, the compounds of the invention can be used to modulate activity of 11βHSD1 in an individual in need of modulation of the enzyme or receptor by administering a modulating amount of a compound of the invention.
The present invention further provides methods of inhibiting the conversion of cortisone to cortisol in a cell, or inhibiting the production of cortisol in a cell, where conversion to or production of cortisol is mediated, at least in part, by 11βHSD1 activity. Methods of measuring conversion rates of cortisone to cortisol and vice versa, as well as methods for measuring levels of cortisone and cortisol in cells, are routine in the art.
The present invention further provides methods of increasing insulin sensitivity of a cell by contacting the cell with a compound of the invention. Methods of measuring insulin sensitivity are routine in the art.
The present invention further provides methods of treating disease associated with activity or expression, including abnormal activity and overexpression, of 11βHSD1 in an individual (e.g., patient) by administering to the individual in need of such treatment a therapeutically effective amount or dose of a compound of the present invention, or pharmaceutically acceptable salt thereof, or a pharmaceutical composition thereof Example diseases can include any disease, disorder or condition that is directly or indirectly linked to expression or activity of the enzyme. An 11βHSD1-associated disease can also include any disease, disorder or condition that can be prevented, ameliorated, or cured by modulating enzyme activity.
Examples of 11βHSD1-associated diseases include obesity, diabetes, glucose intolerance, insulin resistance, hyperglycemia, hypertension, hyperlipidemia, cognitive impairment, dementia, depression (e.g., psychotic depression), glaucoma, cardiovascular disorders, osteoporosis, and inflammation. Further examples of 11βHSD1-associated diseases include metabolic syndrome, type 2 diabetes, androgen excess (hirsutism, menstrual irregularity, hyperandrogenism) and polycystic ovary syndrome (PCOS).
As used herein, the term “cell” is meant to refer to a cell that is in vitro, ex vivo or in vivo. In some embodiments, an ex vivo cell can be part of a tissue sample excised from an organism such as a mammal. In some embodiments, an in vitro cell can be a cell in a cell culture. In some embodiments, an in vivo cell is a cell living in an organism such as a mammal. In some embodiments, the cell is an adipocyte, a pancreatic cell, a hepatocyte, neuron, or cell comprising the eye (ocular cell).
As used herein, the term “contacting” refers to the bringing together of indicated moieties in an in vitro system or an in vivo system. For example, “contacting” the 11βHSD1 enzyme with a compound of the invention includes the administration of a compound of the present invention to an individual or patient, such as a human, having 11βHSD1, as well as, for example, introducing a compound of the invention into a sample containing a cellular or purified preparation containing the 11βHSD1 enzyme.
As used herein, the term “individual” or “patient,” used interchangeably, refers to any animal, including mammals, preferably mice, rats, other rodents, rabbits, dogs, cats, swine, cattle, sheep, horses, or primates, and most preferably humans.
As used herein, the term “treating” or “treatment” refers to one or more of (1) preventing the disease; for example, preventing a disease, condition or disorder in an individual who may be predisposed to the disease, condition or disorder but does not yet experience or display the pathology or symptomatology of the disease; (2) inhibiting the disease; for example, inhibiting a disease, condition or disorder in an individual who is experiencing or displaying the pathology or symptomatology of the disease, condition or disorder; and (3) ameliorating the disease; for example, ameliorating a disease, condition or disorder in an individual who is experiencing or displaying the pathology or symptomatology of the disease, condition or disorder (i.e., reversing the pathology and/or symptomatology) such as decreasing the severity of disease.
When employed as pharmaceuticals, the compounds of the invention can be administered in the form of pharmaceutical compositions which is a combination of a compound of the invention and at least one pharmaceutically acceptable carrier. These compositions can be prepared in a manner well known in the pharmaceutical art, and can be administered by a variety of routes, depending upon whether local or systemic treatment is desired and upon the area to be treated. Administration may be topical (including ophthalmic and to mucous membranes including intranasal, vaginal and rectal delivery), pulmonary (e.g., by inhalation or insufflation of powders or aerosols, including by nebulizer; intratracheal, intranasal, epidermal and transdermal), ocular, oral or parenteral. Methods for ocular delivery can include topical administration (eye drops), subconjunctival, periocular or intravitreal injection or introduction by balloon catheter or ophthalmic inserts surgically placed in the conjunctival sac. Parenteral administration includes intravenous, intraarterial, subcutaneous, intraperitoneal or intramuscular injection or infusion; or intracranial, e.g., intrathecal or intraventricular, administration. Parenteral administration can be in the form of a single bolus dose, or may be, for example, by a continuous perfusion pump. Pharmaceutical compositions and formulations for topical administration may include transdermal patches, ointments, lotions, creams, gels, drops, suppositories, sprays, liquids and powders. Conventional pharmaceutical carriers, aqueous, powder or oily bases, thickeners and the like may be necessary or desirable.
This invention also includes pharmaceutical compositions which contain, as the active ingredient, one or more of the compounds of the invention above in combination with one or more pharmaceutically acceptable carriers. In making the compositions of the invention, the active ingredient is typically mixed with an excipient, diluted by an excipient or enclosed within such a carrier in the form of, for example, a capsule, sachet, paper, or other container. When the excipient serves as a diluent, it can be a solid, semi-solid, or liquid material, which acts as a vehicle, carrier or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments containing, for example, up to 10% by weight of the active compound, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders.
In preparing a formulation, the active compound can be milled to provide the appropriate particle size prior to combining with the other ingredients. If the active compound is substantially insoluble, it can be milled to a particle size of less than 200 mesh. If the active compound is substantially water soluble, the particle size can be adjusted by milling to provide a substantially uniform distribution in the formulation, e.g. about 40 mesh.
The compounds of the invention may be milled using known milling procedures such as wet milling to obtain a particle size appropriate for tablet formation and for other formulation types. Finely divided (nanoparticulate) preparations of the compounds of the invention can be prepared by processes known in the art, for example see International Patent Application No. WO 2002/000196.
Some examples of suitable excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, syrup, and methyl cellulose. The formulations can additionally include: lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying and suspending agents; preserving agents such as methyl- and propylhydroxy-benzoates; sweetening agents; and flavoring agents. The compositions of the invention can be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art.
The compositions can be formulated in a unit dosage form, each dosage containing from about 5 to about 100 mg, more usually about 10 to about 30 mg, of the active ingredient. The term “unit dosage forms” refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient.
The active compound can be effective over a wide dosage range and is generally administered in a pharmaceutically effective amount. It will be understood, however, that the amount of the compound actually administered will usually be determined by a physician, according to the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like.
For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical excipient to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention. When referring to these preformulation compositions as homogeneous, the active ingredient is typically dispersed evenly throughout the composition so that the composition can be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This solid preformulation is then subdivided into unit dosage forms of the type described above containing from, for example, 0.1 to about 500 mg of the active ingredient of the present invention.
The tablets or pills of the present invention can be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permit the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol, and cellulose acetate.
The liquid forms in which the compounds and compositions of the present invention can be incorporated for administration orally or by injection include aqueous solutions, suitably flavored syrups, aqueous or oil suspensions, and flavored emulsions with edible oils such as cottonseed oil, sesame oil, coconut oil, or peanut oil, as well as elixirs and similar pharmaceutical vehicles.
Compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable, aqueous or organic solvents, or mixtures thereof, and powders. The liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as described supra. In some embodiments, the compositions are administered by the oral or nasal respiratory route for local or systemic effect. Compositions in can be nebulized by use of inert gases. Nebulized solutions may be breathed directly from the nebulizing device or the nebulizing device can be attached to a face masks tent, or intermittent positive pressure breathing machine. Solution, suspension, or powder compositions can be administered orally or nasally from devices which deliver the formulation in an appropriate manner.
The amount of compound or composition administered to a patient will vary depending upon what is being administered, the purpose of the administration, such as prophylaxis or therapy, the state of the patient, the manner of administration, and the like. In therapeutic applications, compositions can be administered to a patient already suffering from a disease in an amount sufficient to cure or at least partially arrest the symptoms of the disease and its complications. Effective doses will depend on the disease condition being treated as well as by the judgment of the attending clinician depending upon factors such as the severity of the disease, the age, weight and general condition of the patient, and the like.
The compositions administered to a patient can be in the form of pharmaceutical compositions described above. These compositions can be sterilized by conventional sterilization techniques, or may be sterile filtered. Aqueous solutions can be packaged for use as is, or lyophilized, the lyophilized preparation being combined with a sterile aqueous carrier prior to administration. The pH of the compound preparations typically will be between 3 and 11, more preferably from 5 to 9 and most preferably from 7 to 8. It will be understood that use of certain of the foregoing excipients, carriers, or stabilizers will result in the formation of pharmaceutical salts.
The therapeutic dosage of the compounds of the present invention can vary according to, for example, the particular use for which the treatment is made, the manner of administration of the compound, the health and condition of the patient, and the judgment of the prescribing physician. The proportion or concentration of a compound of the invention in a pharmaceutical composition can vary depending upon a number of factors including dosage, chemical characteristics (e.g., hydrophobicity), and the route of administration. For example, the compounds of the invention can be provided in an aqueous physiological buffer solution containing about 0.1 to about 10% w/v of the compound for parenteral administration. Some typical dose ranges are from about 1 μg/kg to about 1 g/kg of body weight per day. In some embodiments, the dose range is from about 0.01 mg/kg to about 100 mg/kg of body weight per day. The dosage is likely to depend on such variables as the type and extent of progression of the disease or disorder, the overall health status of the particular patient, the relative biological efficacy of the compound selected, formulation of the excipient, and its route of administration. Effective doses can be extrapolated from dose-response curves derived from in vitro or animal model test systems.
The compounds of the invention can also be formulated in combination with one or more additional active ingredients which can include any pharmaceutical agent such as anti-viral agents, vaccines, antibodies, immune enhancers, immune suppressants, anti-inflammatory agents, analgesics, and drugs for the treatment of diabetes or obesity, hyperglycemia, hypertension, hyperlipidemia, and the like. Agents for treatment of metabolic disorders with which a compound of the invention could be combined include, but are not limited to, amylin analogues, incretin mimetics, inhibitors of the incretin-degrading enzyme dipeptidyl peptidase-IV, agonists of peroxisome proliferator-activated receptor (PPAR)-a and PPAR-g, and CB1 cannabinoid receptor inhibitors.
The invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.
EXAMPLES
All compounds were purified by either flash column chromatography or reversed-phase liquid chromatography using a Waters FractionLynx LC-MS system with mass directed fractionation. Column: Waters XBridge C 18 5 μm, 19×100 mm; mobile phase A: 0.15% NH 4 OH in water and mobile phase B: 0.15% NH 4 OH in acetonitrile; the flow rate was 30 ml/m, the separating gradient was optimized for each compound using the Compound Specific Method Optimization protocol as described in literature [“Preparative LC-MS Purification: Improved Compound Specific Method Optimization”, K. Blom, B. Glass, R. Sparks, A. Combs, J. Combi. Chem., 2004, 6, 874-883].
The separated product was then typically subjected to analytical LC/MS for purity check under the following conditions: Instrument; Agilent 1100 series, LC/MSD, Column: Waters Sunfire™ C 18 5 μm, 2.1×5.0 mm, Buffers: mobile phase A: 0.025% TFA in water and mobile phase B: 0.025% TFA in acetonitrile; gradient 2% to 80% of buffer B in 3 min with flow rate 1.5 mL/min.
Example 1
5-{3-Fluoro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}-N-methylpyridine-2-carboxamide
Step 1: 1-benzyl 3-ethylpiperidine-1,3-dicarboxylate
Benzyl chloroformate (Aldrich, cat #:119938) (191 mL, 1.34 mol) was slowly added to a cooled (at 0° C.) mixture of ethyl piperidine-3-carboxylate (Aldrich, cat #:194360) (200 g, 1.27 mol) and triethylamine (266 mL, 1.91 mol) in methylene chloride (1000 mL). The reaction mixture was allowed to gradually warm to ambient temperature and stirred for 3 h. The reaction was quenched by the addition of 1N HCl aq. solution and the product was extracted several times with methylene chloride. The combined extracts were washed with water, saturated aq. NaHCO 3 , water, brine, dried over MgSO 4 , filtered and concentrated under reduced pressure to afford the desired product as oil (359.8 g, 97%). LC/MS 292.2 (M+H) + .
Step 2: 1-benzyl 3-ethyl 3-(3-methylbut-2-en-1-yl)piperidine-1,3-dicarboxylate
To a solution of 1-benzyl 3-ethyl piperidine-1,3-dicarboxylate (120.0 g, 0.412 mol) in THF (400 ml) cooled at −78° C. was added dropwise 270 mL of sodium bis(trimethylsilyl)amide solution (1M solution in THF from Aldrich, cat #:245585) over 2 h. The mixture was stirred at −78° C. for additional 1 h. Then 1-bromo-3-methylbut-2-ene (Aldrich cat #: 249904) (71 mL, 0.62 mol) was added slowly over 1 h. The mixture was stirred at −78° C. for 30 min, and allowed to warm to r.t. and stirred for an additional 3 h. The reaction mixture was quenched with 1N HCl aq. solution. Most of THF was removed under reduced pressure. The residue was extracted with ethyl acetate. The combined extracts were washed with sat. aq. NaHCO 3 and brine, then dried over MgSO 4 , filtered and concentrated under reduced pressure. The crude residue was purified by flash column chromatography on a silica gel column with 10˜20% ethyl acetate in hexane to yield the desired product (140 g, 94%). LC/MS: m/e=332.2 (M+H) + .
Step 3: 1-benzyl 3-ethyl 3-(2-oxoethyl)piperidine-1,3-dicarboxylate
Ozone was passed through a solution of 1-benzyl 3-ethyl 3-(3-methylbut-2-en-1-yl)piperidine-1,3-dicarboxylate (35.2 g, 0.0979 mol) in methylene chloride (800 mL) at −78° C. until the color of the solution turned blue. The reaction mixture was then flushed with nitrogen until the blue color dissipated. Dimethylsulfide (Aldrich, cat #: 274380) (14 mL, 0.19 mol) and triethylamine (26.5 mL, 0.19 mol) were added and the mixture was stirred at ambient temperature overnight. The volatile solvent were removed under reduced pressure and purified directly by flash chromatography on a silica gel column with 20% ethyl acetate in hexanes to afford the desired product in quantitative yield. LC/MS 334.2 (M+H) + .
Step 4: Benzyl 2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate
To a suspension of cis-4-aminocyclohexanol hydrochloride (Available from Sijia Medchem Lab, China) (13.8 g, 0.0910 mol) and 1-benzyl 3-ethyl 3-(2-oxoethyl)piperidine-1,3-dicarboxylate (31.0 g, 0.0930 mol) in 1,2-dichloroethane (250 mL) was added triethylamine (23.3 mL, 0.167 mol) at room temperature. The mixture was stirred at 40° C. overnight. Sodium triacetoxyborohydride (Aldrich, cat #: 316393) (49.3 g, 0.232 mol) was added to the above mixture and stirred at r.t. for 1 h. LC/MS data indicated that the starting material was consumed, and an intermediate product with m/e: 433.2 (M+H) + was observed.
The mixture was then heated at 80° C. for 4 h or until LC/MS showed the intermediate amine (m/e: 433.2) was consumed. The reaction mixture was quenched with aq. NaHCO 3 . The organic layer was washed with brine, dried over MgSO 4 , filtered and concentrated under reduced pressure. The crude material was dried under reduced pressure overnight to give colorless viscous oil (26.9 g, 66.8%). LC/MS m/e 387.2 (M+H) + .
Step 5: Benzyl (5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate
The racemic mixture obtained from above step (26.9 g) was purified on an Agilent 1100 series preparatory system using a Chiralcel OD-H column (3.0×25 cm, 5 micron particle size, Chiral Technologies) eluting with 30% ethanol/hexanes (isocratic, 22 mL/min.). The column loading was approximately 150 mg/injection and peak collection was triggered by UV absorbance at 220 nM. Peak 1 eluted at approximately at 8.5 min. and Peak 2 eluted at approximately 9.8 min. The fractions of Peak 2 were combined and concentrated to provide the desired product (11.9 g) as a white foamy solid. The optical purity of the pooled material from peak 2 was determined by using an Agilent 1100 series analytical system equipped with a Chiralcel OD-H column (4.6×250 mm, 5 micron particle size, Chiral Technologies) and eluting with 30% ethanol/hexanes (isocratic, 0.8 mL/min.). LC/MS m/e 387.2 (M+H) + . The absolute stereochemistry of the peak 2 was established based on X-ray single crystal structure determination of close analogs: Benzyl (5S)-2-(trans-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate and (5S)-2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one prepared as described in Steps 5a-c.
Step 5a: Benzyl 2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate
To a stirred solution of benzyl 2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate (60.00 g, 155.2 mmol) in anhydrous N,N-dimethylformamide (160 mL) at r.t. was added 1H-imidazole (32.0 g, 466 mmol) and tert-butyldimethylsilyl chloride (36.2 g, 233 mmol). The reaction mixture was stirred at r.t. for 4 h, quenched with water (150 mL), and extracted with EtOAc (3×150 mL). The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure to afford the crude product (84 g). The pure product (55.4 g) was obtained by re-crystallization of the crude product from heptane. The mother liquor was concentrated and subjected to purification by flash chromatography on a silical gel column eluting with AcOEt/Haxane to give additional 14.4 g of the product with a total 89.7% yield.
Step 5b: 2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one
To a solution of benzyl 2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate (18.0 g, 35.9 mmol) in methanol (150 mL) was added 10% palladium on carbon (Aldrich, cat #: 520888) (1.8 g, 1.5 mmol) under the atmosphere of nitrogen. The reaction mixture was hydrogenated and shaken at 50 psi for 20 h. The reaction mixture was filtered through a pad of Celite and then washed with methanol (300 mL). The filtrate was concentrated under reduced pressure to give the desired product as a white solid in quantitative yield.
Step 5c: (5S)-2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one
2-(cis-4-{[tert-Butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one (7.00 g, 19.1 mmol) was dissolved in acetonitrile (50 mL) and methanol (7 mL) at r.t. After the starting material was completely dissolved, the solution was heated up to 70° C. To the above solution was slowly added a solution of (2R)-hydroxy(phenyl)acetic acid (1.45 g, 9.55 mmol) in acetonitrile (20 mL) at 65-70° C. After addition, the solution was heated at 74° C. for 10 min, and allowed to cool slowly to room temperature overnight. The crystalline formed was collected by filtration to afford 3.38 g of the desired product as (2R)-hydroxy(phenyl)acetic acid salt. The resulting salt (3.38 g) was dissolved in water (50 mL), and adjusted to pH˜12 with 40 mL aq K 2 CO 3 solution (2.0 M). The mixture was extracted with dichloromethane (3 times). The combined organic layers were dried with magnesium sulfate, filtered, and concentrated under reduced pressure to afford the desired product as a free base (colorless crystalline solid) (2.37 g). The absolute stereochemistry of this compound was established by X-ray single crystal structure determination of (2R)-hydroxy(phenyl)acetic acid salt of (5S)-2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one.
Step 6: (5S)-2-(cis-4-hydroxycyclohexyl)-2,7-diazaspiro[4.5]decan-1-one
Benzyl (5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]decane-7-carboxylate prepared in Step 5 (0.266 g, 0.000688 mol) was dissolved in methanol (5.0 mL) and stirred under an atmosphere of hydrogen in the presence of 10% palladium on carbon (Aldrich, cat #: 520888) (20.0 mg) at r.t. for 2 h. The reaction mixture was filtered and the volatile solvents were removed under reduced pressure to afford the desired product in quantitative yield. LC/MS m/e 253.2 (M+H) + .
Step 7: (5S)-7-(4-bromo-2-fluorophenyl)-2-(cis-4-hydroxycyclohexyl)-2,7-diazaspiro[4.5]decan-1-one
A mixture of (5S)-2-(cis-4-hydroxycyclohexyl)-2,7-diazaspiro[4.5]decan-1-one (1.04 g, 0.00412 mol), 4-bromo-2-fluoro-1-iodobenzene (Aldrich, cat #: 283304) (1.85 g, 0.00615 mol), copper(I) iodide (Aldrich, cat #: 215554) (0.122 g, 0.000640 mol), potassium phosphate (2.63 g, 0.0124 mol) and 1,2-ethanediol (0.48 mL, 0.0086 mol) in 1-butanol (3.90 mL) was heated at 100° C. under nitrogen for 2 d. The reaction was quenched with water, and extracted with ether. The organic layers were combined, washed with water, brine, dried over Na 2 SO 4 , and filtered. The filtrate was evaporated under reduced pressure. The residue was purified by flash column chromatography on a silica gel column eluting with 0 to 5% methanol in DCM to yield the desired product (950 mg, 54.2%). LC/MS m/e 425.1/427.0 (M+H) + .
Step 8: 5-3-fluoro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl-N-methylpyridine-2-carboxamide
Potassium phosphate (637 mg, 0.00300 mol) in water (3.00 mL) was added to a mixture of (5S)-7-(4-bromo-2-fluorophenyl)-2-(cis-4-hydroxycyclohexyl)-2,7-diazaspiro[4.5]decan-1-one (425 mg, 0.00100 mol), N-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-carboxamide (Frontier Inc., cat #: M10074) (393 mg, 0.00150 mol) and tetrakis(triphenylphosphine)palladium (Aldrich, cat #: 216666) (35 mg, 0.000030 mol) in 1,4-dioxane (3.00 mL). The resulting mixture was heated at 120° C. for 24 h. The mixture was diluted with ethyl acetate and washed with water and brine. The organic layer was dried over Na 2 SO 4 , filtered, concentrated under reduced pressure. The residue was purified by flash column chromatography on a silica gel column eluting with 5% methanol in DCM to yield the desired product (285 mg, 59.3%). LC/MS m/e 481.2 (M+H) + . 1 H-NMR (400 MHz, DMSO-d 6 ): 8.89 (1H, dd, J=2.5, 0.6 Hz), 8.76 (1H, q, J=4.7 Hz), 8.22 (1H, dd, J=8.4, 2.5 Hz), 8.03 (1H, dd, J=8.4, 0.6 Hz), 7.65 (1H, dd, J=14.2, 2.1 Hz), 7.56 (1H, dd, J=8.5, 2.1 Hz), 7.13 (1H, t, J=8.5 Hz), 4.37 (1 H, d, J=3.1 Hz), 3.78 (1H, m), 3.71 (1H, m), 3.21-3.38 (3H, m), 3.07 (1H, d, J=11.4 Hz), 2.81 (3H, d, J=4.7 Hz), 2.64-2.74 (2H, m), 2.18-2.26 (1H, m), 1.60-1.91 (8H, m), 1.39-1.51 (3H, m), 1.21-1.30 (2H, m).
Example 2
5-{3-Fluoro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}-N,N-dimethylpyridine-2-carboxamide
Step 1: 5-bromo-N,N-dimethylpyridine-2-carboxamide
Oxalyl chloride (20.0 mL, 0.236 mol) was added to a solution of 5-bromopyridine-2-carboxylic acid (Alfa Aesar, cat #: B25675) (10.1 g, 0.0500 mol) in methylene chloride (60 mL) at r.t. followed by 5 drops of DMF. The mixture was stirred at r.t. for 2 h. The volatiles were evaporated under reduced pressure. The residue was azotropically evaporated with toluene twice. The residue was then dissolved in DCM (30 mL) followed by the addition of 30 mL of dimethylamine in THF solution (2.0 M) (Aldrich, cat #: 391956) and Hunig's base (20.0 mL) (Aldrich, cat #: 496219). The mixture was stirred at r.t. for 3 h. The reaction mixture was diluted with DCM (100 mL) and washed with water, 1N HCl and brine. The organic phase was dried over Na 2 SO 4 , filtered and concentrated to give the desired product (10.5 g, 91.7%).
Step 2: N,N-dimethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-carboxamide
A mixture of 5-bromo-N,N-dimethylpyridine-2-carboxamide (5.73 g, 0.0250 mol), 4,4,5,5,4′,4′,5′,5′-octamethyl-[2,2′]bi[[1,3,2]dioxaborolanyl] (6.98 g, 0.0275 mol) (Aldrich, cat #: 473294), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complexed with dichloromethane (1:1) (0.6 g, 0.0007 mol) (Aldrich, cat #: 379670), 1,1′-bis(diphenylphosphino)ferrocene (0.4 g, 0.8 mmol) (Aldrich, cat #: 177261), and potassium acetate (7.36 g, 0.0750 mol) in 1,4-dioxane (100 mL) was heated at 120° C. for 20 h. After cooling, the mixture was concentrated, diluted with ethyl acetate and washed with sat'd NH 4 Cl solution, water, brine; dried over Na 2 SO 4 . After filtration, the filtrate was concentrated and the crude material was further purified on a silica gel column eluting with ethyl acetate/hexane to give the desired product (4.7 g, 68%).
Step 3: 5-{3-Fluoro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}-N,N-dimethylpyridine-2-carboxamide
This compound was prepared by using procedures that were analogous to those described for the synthesis of Example 1, Step 8 starting from N,N-dimethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-carboxamide and (5S)-7-(4-bromo-2-fluorophenyl)-2-(cis-4-hydroxycyclohexyl)-2,7-diazaspiro[4.5]decan-1-one. LC/MS m/e 495.3 (M+H) + . 1 H-NMR (400 MHz, DMSO-d 6 ): 8.86 (1H, d, J=1.7 Hz), 8.15 (1H, dd, J=8.1, 2.3 Hz), 7.51-7.65 (3H, m), 7.12 (1H, t, J=8.9 Hz), 4.37 (1 H, d, J=3.1 Hz), 3.78 (1H, m), 3.71 (1H, m), 3.22-3.38 (3H, m), 3.06 (1H, d, J=11.7 Hz), 3.00 (3H, s), 2.97 (3H, s), 2.64-2.74 (2H, m), 2.18-2.27 (1H, m), 1.60-1.91 (8H, m), 1.39-1.51 (3H, m), 1.22-1.30 (2H, m).
Example 3
N-Ethyl-5-{3-fluoro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}pyridine-2-carboxamide
Step 1: N-ethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-carboxamide
This compound was prepared by using procedures that were analogous to those described for the synthesis of Example 2, Steps 1 & 2 starting from 5-bromopyridine-2-carboxylic acid.
Step 2: N-Ethyl-5-{3-fluoro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}pyridine-2-carboxamide
This compound was prepared by using procedures that were analogous to those described for the synthesis of Example 1, Step 8 starting from N-ethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-carboxamide and (5S)-7-(4-bromo-2-fluorophenyl)-2-(cis-4-hydroxycyclohexyl)-2,7-diazaspiro[4.5]decan-1-on. LC/MS m/e 495.3 (M+H) + .
Example 4
5-{3-Chloro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}-N-ethylpyridine-2-carboxamide
Step 1: (5S)-7-(4-bromo-2-chlorophenyl)-2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one
A mixture of (5S)-2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one (0.282 g, 0.000769 mol), 4-bromo-2-chloro-1-iodobenzene (0.293 g, 0.000922 mol) (Lancaster, cat #: 19245), copper(I) iodide (0.015 g, 0.000077 mol), potassium phosphate (0.490 g, 0.00231 mol) and 1,2-ethanediol (0.0857 mL, 0.00154 mol) in 1-butanol (0.75 mL) was heated at 100° C. under nitrogen for 2 d. The reaction mixture was filtered, concentrated under reduced pressure, and the residue was purified by flash chromatography on a silica gel column (eluting with 0 to 50% ethyl acetate in hexanes) to afford the desired product.
Step 2: 5-{3-chloro-4-[(5S)-2-(cis-4-hydroxycyclohexyl)-1-oxo-2,7-diazaspiro[4.5]dec-7-yl]phenyl}-N-ethylpyridine-2-carboxamide
To a stirred mixture of (5S)-7-(4-bromo-2-chlorophenyl)-2-(cis-4-{[tert-butyl(dimethyl)silyl]oxy}cyclohexyl)-2,7-diazaspiro[4.5]decan-1-one (20 mg, 0.00004 mol), [1,1 ′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (1:1) (2.0 mg), tetrakis(triphenylphosphine)palladium (1.0 mg) and potassium carbonate (14.9 mg, 0.000108 mol) in anhydrous N,N-dimethylformamide (1 mL) was added N-ethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine-2-carboxamide (14.5 mg, 0.054 mmol). The resulting reaction mixture was heated at 150° C. and stirred overnight, followed by the removal of TBS protecting group by the addition of 1.7 M of fluorosilicic acid in water (0.10 mL) and the mixture was stirred at r.t. overnight. The reaction mixture was then directly purified by RP-HPLC to afford the desired product. LC/MS m/e 511.2 (M+H) + . 1 H-NMR (400 MHz, DMSO-d 6 ): 8.92 (1H, d, J=2.3 Hz), 8.84 (1H, t, J=5.9 Hz), 8.26 (1H, dd, J=8.2, 2.3 Hz), 8.06 (1H, d, J=8.2 Hz), 7.89 (1H, d, J=2.2 Hz), 7.74 (1H, dd, J=8.5, 2.2 Hz), 7.30 (1H, t, J=8.5 Hz), 4.39 (1 H, d, J=3.1 Hz), 3.80 (1H, m), 3.72 (1H, m), 3.24-3.44 (5H, m), 3.01 (1H, d, J=11.4 Hz), 2.63-2.74 (2H, m), 2.40-2.53 (1H, m), 1.64-1.91 (8H, m), 1.41-1.53 (3H, m), 1.20-1.32 (2H, m), 1.13 (3H, t, J=7.2 Hz).
Example 5
Enzymatic Assay of 11βHSD1
All in vitro assays were performed with clarified lysates as the source of 11βHSD1 activity. HEK-293 transient transfectants expressing an epitope-tagged version of full-length human 11βHSD1 were harvested by centrifugation. Roughly 2×10 7 cells were resuspended in 40 mL of lysis buffer (25 mM Tris-HCl, pH 7.5, 0.1 M NaCl, 1 mM MgCl 2 and 250 mM sucrose) and lysed in a microfluidizer. Lysates were clarified by centrifugation and the supernatants were aliquoted and frozen.
Inhibition of 11βHSD1 by test compounds was assessed in vitro by a Scintillation Proximity Assay (SPA). Dry test compounds were dissolved at 5 mM in DMSO. These were diluted in DMSO to suitable concentrations for the SPA assay. 0.8 μL of 2-fold serial dilutions of compounds were dotted on 384 well plates in DMSO such that 3 logs of compound concentration were covered. 20 μL of clarified lysate was added to each well. Reactions were initiated by addition of 20 μL of substrate-cofactor mix in assay buffer (25 mM Tris-HCl, pH 7.5, 0.1 M NaCl, 1 mM MgCl 2 ) to final concentrations of 400 μM NADPH, 25 nM 3 H-cortisone and 0.007% Triton X-100. Plates were incubated at 37° C. for one hour. Reactions were quenched by addition of 40 μL of anti-mouse coated SPA beads that had been pre-incubated with 10 μM carbenoxolone and a cortisol-specific monoclonal antibody. Quenched plates were incubated for a minimum of 30 minutes at RT prior to reading on a Topcount scintillation counter. Controls with no lysate, inhibited lysate, and with no mAb were run routinely. Roughly 30% of input cortisone is reduced by 11βHSD1 in the uninhibited reaction under these conditions.
Example 6
Cell-Based Assay for 11βHSD1 Activity
Peripheral blood mononuclear cells (PBMCS) were isolated from normal human volunteers by Ficoll density centrifugation. Cells were plated at 4×10 5 cells/well in 200 μL of AIM V (Gibco-BRL) media in 96 well plates. The cells were stimulated overnight with 50 ng/ml recombinant human IL-4 (R&D Systems). The following morning, 200 nM cortisone (Sigma) was added in the presence or absence of various concentrations of compound. The cells were incubated for 48 hours and then supernatants were harvested. Conversion of cortisone to cortisol was determined by a commercially available ELISA (Assay Design).
Various modifications of the invention, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. Each reference, including all patent, patent applications, and publications, cited in the present application is incorporated herein by reference in its entirety.
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The present invention relates to certain spirocyclic compounds that are inhibitors of 11-β hydroxyl steroid dehydrogenase type 1 (11βHSD1), compositions containing the same, and methods of using the same for the treatment of diabetes, obesity and other diseases.
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This is a continuation-in-part of application(s) Ser. No. 08/307,545 filed on Sep. 16, 1994, now U.S. Pat. No. 5,424,348.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to stabilizer blends and related polymer stabilization processes, and more particularly relates to stabilizer blends containing a phosphite and related polymer stabilization processes.
2. Description of the Related Art
Blends of phosphites and other stabilizers are generally known, and have been used for stabilizing polymer compositions. Such blends can provide the advantage of a single additive product for delivery into a polymer composition. A problem with such blends can exist for solid blend products if the components do not adequately adhere to each other resulting in particles of the blends losing their integrity and forming undesirable amounts of dust. Another problem with such blends can exist if high levels of phosphite are desired and the components, in particular the phosphite, and the other components, do not adequately adhere to each other.
Accordingly, there is a need to provide blends containing a phosphite which exhibit enhanced adhesion between the blend components.
SUMMARY OF THE INVENTION
The present invention involves stabilizer blends containing a phosphite of the formula: ##STR2## wherein Y 1 is an alkyl and Y 2 is tert-butyl. The blends are in the form of solid particles and exhibit reduced dust formation and/or allow for high loadings of phosphite due to the enhanced adhesive characteristics of the phosphite. The solid particles may be used to stabilize thermoplastic compositions.
DETAILED DESCRIPTION OF THE INVENTION
The solid stabilizer blend composition contains (a) a phosphite of the formula: ##STR3## wherein Y 1 is an alkyl and Y 2 is tert-butyl, and (b) an additive component such as hindered phenols, neutralizers, hydroxylamines, thioesters and ultraviolet light stabilizers and absorbers. The phosphite is preferably present in the composition at a level of from 5 percent by weight to 95 percent by weight. The composition is preferably in the form of particles having a particle size of from 10 μm to 2 mm. The particles can be used to stabilize thermoplastic materials by addition thereto. The particles exhibit reduced levels of dust and are suitable for high loadings of phosphite.
The present invention involves a neoalkyl aryl phosphite of the formula: ##STR4## wherein Y 1 is independently selected from the group consisting of alkyl radicals, and preferably Y 1 is a tert-butyl group and Y 2 is a tert-butyl group.
The phosphite may be made by the reaction of 2-ethyl-2-butyl-1,3-propane diol with PCl 3 in the absence of a catalyst, HCl acceptor and solvent to produce an intermediate product of the formula: ##STR5## followed by the reaction with a hydroxyaryl compound of the formula: ##STR6## wherein Y 1 and Y 2 are as defined above. Suitable reaction methods are set out in Great Britain Patent 2087399A, U.S. Pat. No. 4,318,845 issued 1982, Spivak et al. and Article in Phosphourous & Sulfur Journal by J. D. Spivak et al. 1983, vol. 15, pp. 9-13, all of which are incorporated herein by reference.
The reaction between the diol and PCl 3 may be conducted in known manner, as by mixing the reactants together at room temperature, or preferably, by cooling the PCl 3 to a temperature between 5-15 degrees centigrade prior to addition of diol to the reactor. An excess of either reactant may be employed although it is preferred to operate with substantially stoichiometric amounts of the diol and PCl 3 . The reaction temperature is preferably maintained between 5-15 degrees centigrade. This temperature may be readily controlled by regulating the rate of diol addition. The esterification reaction is quite exothermic in the absence of a solvent, but a temperature moderating effect is produced by the cooling effect of vigorous HCl evolution. Hence, by effective control of diol addition, the reaction may be made self-regulating in the temperature range between 5-15 degrees centigrade.
After the reaction has gone to completion, the bulk of the by-product HCl may optionally be removed by gently raising the temperature of the product to about 50 degrees centigrade and applying a vacuum.
The reaction between the intermediate product of the reaction discussed in the preceding paragraph and hydroxyaryl compound may be conducted in the same reaction vessel that was employed to produce the crude intermediate by merely introducing the hydroxyaryl compound into the reactor.
The reaction between the hydroxyaryl compound and the intermediate product in some instances may be carried out at a temperature between 35 to 100 degrees centigrade and preferably between about 45 to about 80 degrees centigrade. The pressure of the reaction system is maintained between about 50 millimeters mercury absolute to atmospheric pressure. The reaction reaches substantial completion in from 1 to about 8 hours and for practical purposes it is preferably operated under temperature and pressure conditions which will afford the maximum amount of product within 3 to about 5 hours. Although a stoichiometric excess of either reactant may be employed, it is preferred to operate with substantially stoichiometric quantities.
The hydroxyaryl compound may be any compound of the formula: ##STR7## in which Y 1 is selected from the group consisting of alkyl groups preferably having from 1 to 8 carbon atoms, more preferably methyl or t-butyl. The reaction can be completed in the presence of a base such as an amine acceptor. Since Y 1 is an alkyl group, an amine acceptor should be added to help drive this reaction. If Y 1 is a tert-alkyl group, such as t-butyl, then a stociometeric amount of amine acceptor should be present. Y 2 is t-butyl, and the phosphite is a solid at room temperature.
After completion or near completion of the reaction, HCl generated during the process may readily be substantially removed by evacuating the reactor vessel. No special precautions need to be taken to remove all the HCl present, as by addition of HCl acceptor or via controlled neutralization of the acidity. The product may then be recovered by distillation, or crystallization.
The phosphites have Y 1 as an alkyl group such as methyl or t-butyl in order to inhibit ultraviolet light yellowing of the phosphite. If Y 1 is hydrogen the phosphite will have sensitivity to UV yellowing. The preferred phosphite has a phenolic degradation product boiling point of greater than 250° C., more preferably greater than 260° C. so that the volatility of the degradation product during processing of the stabilized polymer, such as polyolefins such as polypropylene which processes at 240° C. and above, is minimized. The problem of excessive volatiles can be minimized by employing an 2,4-di-butyl-6-alkyl phenyl group because such groups have corresponding 2,4-di-butyl-6-alkyl phenol degradation products which have a boiling point of greater than 260° C.
The additive component may be selected from antioxidants, ultraviolet (UV) light absorbers and UV light stabilizers, metal deactivates, phosphites (other than component) and phosphonites, peroxide scavengers, polyamide stabilizers, basic co-stabilizers (neutralizers), nucleating agent, hydroxylamines such as dialkyl aminoxy propane and more generally such as R 2 NOH wherein R is a C 1 to C 30 alkyl group such as propyl and stearyl, thioesters, and aminoxy propanote derivatives. The preferred additives are hindered phenolic antioxidants, UV absorbers, UV stabilizers and neutralizers.
Suitable additive components are selected from:
1. Antioxidants
1.1 Alkylated monophenols, for example: 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(alpha-methylcyclohexyl)-4,6 dimethylphenol, 2,6-di-octadecyl-4-methylphenol, 2,4,6,-tricyclohexyphenol, 2,6-di-tert-butyl-4-methoxymethylphenol.
1.2 Alkylated hydroquinones, for example, 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amyl-hydroquinone, 2,6-diphenyl-4octadecyloxyphenol.
1.3 Hydroxylated thiodiphenyl ethers, for example, 2,2'-thio-bis-(6-tert-butyl-4-methylphenol), 2,2'-thio-bis-(4-octylphenol), 4,4'thio-bis-(6-tert-butyl-3-methylphenol), 4,4'-thio-bis-(6-tert-butyl-2-methylphenol).
1.4 Alkylidene-bisphenols, for example, 2,2'-methylene-bis-(6-tert-butyl-4-methylphenol), 2,2'-methylene-bis-(6-tert-butyl-4-ethylphenol), 2,2'-methylene-bis-(4-methyl-6-(alpha-methylcyclohexyl(phenol), 2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis-(6-nonyl-4-methylphenol), 2,2'-methylene-bis-(6-nonyl-4-methylphenol), 2,2'-methylene-bis-(6-(alpha-methylbenzyl)-4-nonylphenol), 2,2'-methylene-bis-(6-(alpha,alpha-dimethylbenzyl)-4-nonyl-phenol)- 2,2'-methylene-bis-(4,6-di-tert-butylphenol), 2,2'-ethylidene-bis-(6-tert-butyl-4-isobutylphenol), 4,4'-methylene-bis-(2,6-di-tert-butylphenol), 4,4'-methylene-bis-(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenol)butane. 2,6-di-(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol, 1,1,3-tris-(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-dodecyl-mercaptobutane, ethyleneglycol-bis-(3,3,-bis-(3'-tert-butyl-4'-hydroxyphenyl)-butyrate)-di-(3-tert-butyl-4-hydroxy-5-methylphenyl)-dicyclopentadiene, di-(2-(3'-tert-butyl-2'hydroxy-5'methyl-benzyl)-6-tert-butyl-4-methylphenyl)terephthalate.
1.5 Benzyl compounds, for example, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, bis-(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, isooctyl 3,5-di-tert-butyl-4-hydroxybenzyl-mercapto-acetate, bis-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol-terephthalate. 1,3,5-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate. 1,3,5-tris-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, dioctadecyl 3,5-diotert-butyl-4-hydroxybenzylphosphonate, calcium salt of monoethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 1,3,5-tris-(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.
1.6 Acylaminophenols, for example, 4-hydroxylauric acid anilide, 4-hydroxy-stearic acid amilide, 2,4-bis-octylmercapto-6-(3,5-tert-butyl-4-hydroxyanilino)-s-triazine, octyl-N-(3,5-di-tert-butyl-4-hydroxyphenyl)-carbamate.
1.7 Esters of beta-(3,5-di-tert-butyl-4-hydroxyphenol)-propionic acid with monohydric or polyhydric alcohols, for example, methanol, diethyleneglycol, octadecanol, triethyleneglycol, 1,6-hexanediol, penta-erythritol, neopentylglycol, tris-hydroxyethylisocyanurate, thiodiethyleneglycol, di-hydroxyethyl oxalic acid diamide.
1.8 Esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)-propionic acid with monohydric or polyhydric alcohols, for example, methanol, diethyleneglycol, octadecanol, triethyleneglycol, 1,6-hexanediol, pentaerythritol, neopentylglycol, tris-hydroxyethyl isocyanurate, thidiethyleneglycol, dihydroxyethyl oxalic acid diamide.
1.9 Esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl) propionic acid with mono-or polyhydric alcohols, e.g., with methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris(hydroxyethyl) isocyanurate, thiodiethylene glycol, N,N-bis(hydroxyethyl) oxalic acid diamide.
1.10 Amides of beta-(3,5-di-tert-butyl-4-hydroxyphenol)-propionic acid for example, N,N'-di-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-hexamethylen-diamine, N,N'-di-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine, N,N'-di(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.
2. UV absorbers and light stabilizers.
2.1 2-(2'-hydroxyphenyl)-benzotriazoles, for example, the 5'methyl-, 3'5'-di-tert-butyl-, 5'-tert-butyl-,5'(1,1,3,3-tetramethylbutyl) -,5-chloro-3', 5'-di-tert-butyl-, 5-chloro -3'tert-butyl-5'methyl -,3'sec-butyl-5'tert-butyl-,4'-octoxy,3',5'-ditert-amyl-3',5'-bis-(alpha, alpha-dimethylbenzyl)-derivatives.
2.2 2-Hydroxy-benzophenones, for example, the 4-hydroxy-4-methoxy-,4-octoxy,4-decloxy-,4-dodecyloxy-,4-benzyloxy,4,2',4'-trihydroxy-and 2'hydroxy-4,4'-dimethoxy derivative.
2.3 Esters of substituted and unsubstituted benzoic acids for example, phenyl salicylate, 4-tert-butylphenyl-salicilate, octylphenyl salicylate, dibenzoylresorcinol, bis-(4-tert-butylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-tert-butyl-phenyl-3,5-di-tert-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate.
2.4 Acrylates, for example, alpha-cyano-beta, beta-diphenylacrylic acid-ethyl ester or isooctyl ester, alpha-carbomethoxy-cinnamic acid methyl ester, alpha-cyano-beta-methyl-p-methoxy-cinnamic acid methyl ester or butyl ester, alpha-carbomethoxy-p-methoxy-cinnamic acid methyl ester, N-(beta-carbomethoxy-beta-cyano-vinyl)-2-methyl-indoline.
2.5 Nickel compounds, for example, nickel complexes of 2,2'-thio-bis(4-(1,1,1,3-tetramethylbutyl)-phenol), such as the 1:1 or 1:2 complex, optionally with additional ligands such as n-butylamine, triethanolamine or N-cyclohexyl-diethanolamine, nickel dibutyldithiocarbamate, nickel salts of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid monoalkyl esters, such as of the methyl, ethyl, or butyl ester, nickel complexes of ketoximes such as of 2-hydroxy-4-methyl-penyl undecyl ketoxime, nickel complexes of 1-phenyl-4-lauroyl-5-hydroxy-pyrazole, optionally with additional ligands.
2.6 Sterically hindered amines, for example bis(2,2,6,6-tetramethylpiperidyl)-sebacate, bis-(1,2,2,6,6-pentamethylpiperidyl)-sebacate, n-butyl-3,5-di-tert-butyl-4-hydroxybenzyl malonic acid bis(1,2,2,6,6,-pentamethylpiperidyl)ester, condensation product of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidine and succinic acid, condensation product of N,N'-(2,2,6,6-tetramethylpiperidyl)-hexamethylendiamine and 4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine, tris-(2,2,6,6-tetramethylpiperidyl)-nitrilotriacetate, tetrakis-(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetra-carbonic acid, 1,1'(1,2-ethanediyl)-bis-(3,3,5,5-tetramethylpiperazinone). Such amines include hydroxylamines derived from hindered amines, such as di(1-hydroxy-2,2,6,6-tetramethylpiperidin-4yl)sebacate: 1-hydroxy 2,2,6,6-tetramethyl-4-benzoxypiperidine; 1-hydroxy-2,2,6,6-tetramethyl-4-(3,5-di-tert-butyl-4-hydroxy hydrocinnamoyloxy)piperdine; and N-(1-hydroxy-2,2,6,6-tetramethyl-piperidin-4-yl)-epsiloncaprolactam.
2.7 Oxalic acid diamides, for examples, 4,4'-dioctyloxy-oxanilide, 2,2'-di-octyloxy-5',5'-di-tertbutyloxanilide, 2,2'-di-dodecyloxy-5',5'di-tert-butyl-oxanilide, 2-ethoxy-2'-ethyl-oxanilide, N,N'-bis(3-dimethylaminopropyl)-oxalamide, 2-ethoxy-5-tert-butyl-2'-ethyloxanilide and its mixture with 2-ethoxy-2'ethyl-5,4-di-tert-butyloxanilide and mixtures of ortho-and para-methoxy-as well as of o- and p-ethoxy-disubstituted oxanilides.
3. Metal deactivators, for example, N,N'-diphenyloxalic acid diamide, N-salicylal-N'-salicyloylhydrazine, N,N'-bis-salicyloylhydrazine, N,N'-bis-(3,5-di-tert-butyl-4-hydrophenylpropionyl)-hydrazine, salicyloylamino-1,2,4-triazole, bis-benzyliden-oxalic acid dihydrazide.
4. Phosphites and phosphonites, for example, triphenyl phosphite, diphenylalkyl phosphites, phenyldialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl)phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite tristearyl sorbitol triphosphite, and tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite.
5. Peroxide scavengers, for example, esters of betathiodipropionic acid, for example the lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercaptobenzimidazole, zinc-dibutyldithiocaramate, dioctadecyldisulfide, pentaerythritoltetrakis-(beta-dodecylmercapto)-propionate.
6. Polyamide stabilizers, for example copper salts in combination with iodides and/or phosphorus compounds and salts of divalent manganese.
7. Basic co-stabilizers, for example, melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, alkali metal salts and alkaline earth metal salts of higher fatty acids, for example, Ca stearate, calcium stearoyl lactate, calcium lactate, Zn stearate, Mg stearate, Na ricinoleate and K palmitate, antimony pyrocatecholate or zinc pyrocatecholate.
8. Nucleating agents, for example, 4-tert butylbenzoic acid, adipic acid, diphenylacetic acid.
9. The present invention may also be used in conjunction with aminoxy propanoate derivatives such as methyl-3-(N,N-dibenzylaminoxy)propanoate; ethyl-3-(N,N-dibenzylaminoxy)propanonoate; 1,6-hexamethylene-bis(3-N,N-dibenzylehminoxy)proponoate); methyl-(2-(methyl)-3(N,N-dibenzylaminoxy)propanoate); octadecyl-3-(N,N-dibenzylaminoxy)propanoic acid; tetrakis (N,N-dibenzylaminoxy)ethyl carbonyl oxymethy)methane; octadecyl-3-(N,N-diethylaminoxy)-propanoate; 3-(N,N-dibenzylaminoxy)propanoic acid potassium salt; and 1,6-hexamethylene bis(3-(N-allyl-N-dodecyl aminoxy)propanoate).
10. Suitable thio components (preferably thioesters) include 1,1,1-trimethylolethane tri(mercaptoacetate), 1,1,1 -trimethylolpropane tri(mercaptoacetate), dioleyl thiodipropionate, dilauryl thiodipropionate, other thio compounds include distearyl 3,3'-thiodipropionate, dicyclohexyl -3,3'-thiodipropionate, dicetyl-3,3'-thiodipropionate, dioctyl-3,3'-thiodipropionate, dibenzyl-3,3'-thiodipropionate, laurylmyristyl-3,3'-thiodipropionate, diphenyl-3,3'-thiodipropionate, di-p-methoxyphenyl-3,3'-thiodipropionate, didecyl-3,3'-thiodipropionate, dibenzyl-3,3'-thiodipropionate, diethyl-3,3'-thiodipropionate, lauryl ester of 3-methyl-mercapto propionic acid, lauryl ester of 3-butyl-mercapto propionic acid, lauryl ester of 3lauryl-mercapto propionic acid, phenyl ester of 3-octylmercapto propionic acid, lauryl ester of 3-phenylmercapto propionic acid, lauryl ester of 3-benzylmercapto propionic acid, lauryl ester of 3-(p-methoxy) phenylmercapto propionic acid, lauryl ester of 3-cyclo-hexylmercapto propionic acid, lauryl ester of 3-hydroxy-methylmercaptopropionic acid, myristyl ester of 3-hydroxy-ethylmercapto propionic acid, octyl ester of 3-methoxy-methylmercapto propionic acid, dilauryl ester of 3-carboxyl-methylmercapto propionic acid, dilauryl ester of 3-carboxy-propylmercapto propionic acid, dilauryl-4,7-dithiasebacate, dilauryl-4,7,8,11-tetrathiotetradecandioate, dimyristyl-4,11-dithiatetradecandioate, lauryl-3-benzothiazylmercapto-propionate. Preferably the esterifying alcohol is an alkanol having 10 to 18 carbon atoms. Other esters of beta thiocarboxylic acids set forth in Gribbins U.S. Pat. No. 2,519,744 can also be used.
The blend composition preferably comprises the phosphite at a level of from 5 to 95 percent by weight based on the total weight of the composition, more preferably from 10 to 90 percent by weight thereof, and most preferably from 40 to 60 percent by weight thereof; and preferably comprises the additive component at a level of from 5 to 95 percent by weight based on the total weight of the composition, more preferably from 10 to 90 percent by weight thereof, and most preferably from 40 to 60 percent by weight thereof.
The blend composition is preferably in the form of particles having a number average diameter of between 10 μm and 2 mm, more preferably from 50 μm to 1 mm, and most preferably from 100 μm to 500 μm.
The particles are preferably made by compacting under pressure powders of the phosphite and the additive component.
The compacted particles may be added to thermoplastic composition for stabilization thereof. The particles are preferably incorporated into the thermoplastic composition at a level of from 0.01 percent by weight to 5 percent by weight based on the total weight of the composition, more preferably at a level of from 0.03 to 3 percent by weight thereof, and most preferably from 0.05 to 1 percent by weight thereof.
The preferred thermoplastics are olefin polymers. The olefin polymers contemplated herein include homopolymers and copolymers of monoolefins, preferably those monoolefins containing 1-4 carbon atoms. Illustrative examples include polyethylene (including low density, high density, ultra high molecular weight and linear low density polyethylene), polypropylene, EPDM polymers, ethylene-propylene copolymers and polyisobutylene. The stabilization of mixtures of any of these olefin polymers and copolymers likewise is contemplated.
Polyamides prepared from hexamethylene diamine and isophthalic or/and terephthalic acid and optionally an elastomer as modifier, for example poly-2,4,4-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide may be useful. Further copolymers of the aforementioned polyamides with polyolefins, olefin copolymers, ionomers or chemically bonded or grafted elastomers; or with polyethers, such as for instance, with polyethylene glycol, polypropylene glycol or polytetramethylene glycols and polyamides or copolyamides modified with EPDM or ABS may be used.
Polyolefin, polyalkylene terephthalate, polyphenylene ether and styrenic resins, and mixtures thereof are more preferred, with polyethylene, polypropylene, polyethylene terephthalate, polyphenylene ether homopolymers and copolymers, polystyrene, high impact polystyrene, polycarbonates and ABS-type graft copolymers and mixtures thereof being particularly preferred.
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A stabilizer blend composition is provided containing a phosphite of the formula: ##STR1## wherein Y 1 is an alkyl and Y 2 is tert-butyl, and an additive which is preferably a hindered phenolic, a thioester, a neutralizer, a UV stabilizer or a UV absorber. The composition in solid particle form exhibit reduced levels of dusting and are useful in polymer stabilization processes for stabilizing polymeric materials.
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BACKGROUND OF THE INVENTION
This invention relates to a method and apparatus for tinting yarn and, more particularly, to a method and apparatus for applying a fugitive tint to a yarn to identify the yarn.
Generally, an end user, such as a carpet manufacturer, may receive from a yarn producer different types of yarn, having different dyeabilities, tenacities or other properties. Conventionally, the type of yarn is indicated on each package of yarn received from the yarn producer, but when the yarn is removed from the package, it is often impossible for the end user to distinguish it from other types of yarn. This is especially a problem in such processes as twisting, tufting, and mending where several packages of yarn may be used.
Fugitive tints, such as water-soluble dyes have been applied to yarns to enable the type of yarn to be identified by end users. Versatint* N-6 dye (Milliken Laboratories - USA) is normally used on nylon staple while Versatint II dye is recommended for BCF nylon yarns. Other commercially available fugative tints include Megatint* dye (Chemurgy Products Inc). Such tints are removable from the yarn prior to the final processing steps so that product quality is not adversely affected. Attempts have been made to apply such tint to yarn by spraying it onto yarn packages. This has the disadvantage of being messy and environmentally hazardous due to the presence of excess air-borne tint. Moreover, the visibility of the tint along the threadline is low once the yarn is removed from the package and after such operations as twisting, the tint is even more difficult to see.
STATEMENT OF THE INVENTION
It is an object of the present invention to obviate or mitigate the above-mentioned disadvantages.
Accordingly, the invention provides an apparatus for producing heat-set, tinted yarn comprising:
yarn heat setting means; and
yarn tinting means for tinting said yarn after heat setting in said yarn heat setting means, said yarn tinting means comprising a tinting chamber having openings therein to allow for passage of yarn therethrough, yarn guide means for guiding said yarn through said tinting chamber, spray nozzles locatable within said chamber for spraying tint onto said yarn within said chamber and means for exhausting excess tint from said chamber.
In another one of its aspects, the invention provides an apparatus for tinting yarn, said yarn tinting apparatus comprising a tinting chamber having openings therein to allow for passage of yarn therethrough, yarn guide means for guiding said yarn through said tinting chamber, spray nozzles locatable within said chamber for spraying tint onto said yarn within said chamber and means for exhausting excess tint from said chamber.
In a further one of its aspects, the invention provides a process for tinting yarn comprising passing yarn through an at least partially enclosed spraying zone, spraying yarn with tint in said spraying zone, and simultaneously removing excess tint from said spraying zone.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the present invention, the yarn is sprayed continuously in an at least partially enclosed chamber and excess tint is continuously removed from the system to reduce the amount of undesirable deposits of excess tint and to reduce the health hazard created by air-borne excess tint.
The process of the present invention may be carried out by the yarn producer in the yarn production line or by the end user. Preferably, the yarn is heat-treated prior to tinting, since heat-treating after tinting may cause the tint to be permanently fixed to the yarn. Heat-treatment may be performed in a batchwise manner in an autoclave or may be performed continuously in a commercially available continuous heat treating apparatus. These continous apparatuses generally comprise an enclosed steam heating zone in which the heat treating takes place followed by a cooling zone which is open to ambient conditions and which is sufficiently long to allow the yarn to cool prior to being wound onto a package. For space saving reasons, the cooling zone is often located above the heating zone. A pair of guides may be used, one to guide the yarn from the exit of the heating zone to the region above the heating zone and one to guide the yarn to a winding apparatus. Ideally, the tinting apparatus is located in the cooling zone of the heat treating apparauts, since the guides of this zone can be adjusted to guide the yarn into the tint applicator. Also, the yarn in this zone is usually at an ideal temperature for tinting because it is sufficiently cool that the tint will not be permanently bonded to the yarn, but is still warm enough to enhance coverage of the yarn with tint.
The tint applicator of the invention preferably employs compressed air to siphon tint from a tint reservoir and to atomize the tint through at least one spray nozzle. Compressed air is generally readily available from the heat treating apparatus since these apparatuses tend to rely on compressed air to operate their heating zones at elevated temperatures.
To ensure that excess tint is removed from the system and returned to a tint reservoir, the tint applicator preferably employs deflectors to deflect excess tint away from the openings in the tint chamber and a suction generating apparatus such as a vortex generator in a drain in the base thereof. Compressed air is preferably employed to generate the vortex.
Preferred embodiments of the invention will be further described, by way of illustration only, with reference to the following drawings, in which:
FIG. 1 is a perspective view of a heat-setting apparatus with a tint applicator mounted thereon;
FIG. 2 is side view of the tint applicator of FIG. 1;
FIG. 3 is a top view of the tint applicator of FIG. 1; and
FIG. 4 is a cross sectional view of the chamber of the tint applicator of FIG. 1.
Referring to FIG. 1, a heat setting apparatus 10 having a tint applicator 11 mounted thereon is shown. This apparatus 10 has two identical lines 12, each of which includes a coiling apparatus 14, followed by a prebulker 16 connected to a first cooling chimney 18. In line with this first cooling chimney 18 is a heat setting tunnel 20 followed by a second cooling chimney 22. Yarn 23 is passed through these apparatuses and then is guided by a first guide 24 over the top of the heat setting apparatus 10 to the tint applicator 11 mounted on top of the heat setting tunnel 20. The yarn 23 passes through this applicator 11 to a second guide 28 which reverses the yarn and guides it back into the tint applicator 11 for a second time. The yarn then passes over the first guide 24 and is wound onto packages 30 in a winding apparatus 32.
Details of the tint applicator 11 can be seen in FIGS. 2 and 3. The tint applicator 11 comprises a tinting chamber 34 mounted on top of a tint reservoir 36. The tinting chamber 34 is defined by an upper enclosure 38 and a lower enclosure 40 connected together by a leak resistant hinge 42. A pair of spray jets 44 are located on top of the upper enclosure 38 with their nozzles 46 extending into the chamber 34 through holes 48 in roof 50 of the upper enclosure 38. The nozzles 46 are adapted to each spray a fine jet of tint perpendicular to yarn passing through the chamber.
An opening 52 is provided between each of the side walls 54 of the upper enclosure 38 and the lower enclosure 40 to allow yarn to pass through the chamber 34. Guides 56 are attached to the lower enclosure 40 on each of the side walls 54 to guide yarn into the openings 52.
The front wall 58 of the upper enclosure 38 is provided with a handle 60 and the rear wall 62 of the lower enclosure 40 is provided with a bumper 64 to allow the upper enclosure 38 to be rotated relative to the lower enclosure 40 until it rests on the bumber 64 to provide access to the chamber 34.
The bottom 66 of the lower enclosure 40 is provided with sloping walls 68 leading downwardly to a drain opening 70. A fine mesh screen covers this opening to trap loose fibres, lint undesirables and particles. A drain 72 extends from this opening 70 to the roof 94 of the reservoir 36. A vortex generator 76 is located in this drain to generate a vortex to ensure removal of vapourized excess tint from the chamber. Extending perpendicularly from the drain 72 into the reservoir is flexible liquid tubing 78 attached to the roof 94 of the reservoir by clamps 80.
Details of the interior or the upper and lower enclosures can be seen in FIG. 4. Baffles 82 are mounted on the inner side walls 84 of the upper enclosure 38 above each of the openings 52 to deflect spray from the nozzles 46 away from the openings 52. Similarly, baffles 86 are mounted on the inner side walls 88 of the lower enclosure 40 below each of the openings 52 to deflect spray away from the openings and towards the drain opening 70.
Referring back to FIGS. 2 and 3, it can be seen that the lower enclosure 40 is supported by four legs 90, one at each corner thereof. These legs 90 are welded in place and are welded at their bases 92 to the roof 94 of the reservoir 36. Also located on the roof of the reservoir is a solenoid valve 96 connected to an compressed air supply (not shown). This valve 96 operates on 110 V and directs air on command to pressure regulators associated therewith and are connected by two pieces of PVC air tubing 98 (partially indicated by ghost outline) to the jets 44 and the vortex generator 76 respectively. As can be most clearly seen in FIG. 3, adjacent to the valve 96 is an opening 100 in the roof 94 of the reservoir, which is covered by a cover plate 102. A breather cap 104 is located in this plate 102 to release pressure created in the reservoir by the vortex generator 76. The underside of this plate is provided with a filter material layer (not shown) to impede the escape of tint mist from the reservoir. The base 106 of the reservoir slopes towards the corner 108 of the reservoir that is beneath this plate 102. A drain 110 is located in this corner having a valve 112 therein. Also located in this corner 108 is a filter 114 (shown in dotted outline) which is connected to two pieces of PVC liquid tubing 116 leading to respective ones of the spray jets 44. This filter 114 is intended to trap lint that might be resident in the reservoir. On an outer wall 118 of the reservoir adjacent to this corner is mounted a sight glass 120 to allow detection of the level of tint in the reservoir.
The reservoir is supported by four legs 122, one at each corner thereof. These legs rest on the top of the heat setting tunnel 20 at a suitable location before the second cooling chimney 22 as illustrated in FIG. 1.
In operation, yarn is passed through the openings 52 in the side walls 54. Tint is withdrawn from the reservoir and is pneumatically sprayed onto the yarn by the jets 44. The baffle plates 82, 86 deflect tint spray away from the openings 52. The vortex generator 76 draws excess tint mist out of the chamber and directs it back into the reservoir 36.
In a particularly preferred unit, the heat setting machine 10 used is the Superba heat setting unit (type TVP). The spray jets are preferably Spraying Systems Co. spray jets with flat spray air atomizing nozzles of the 1/4J Series. The vortex generator is preferably a Vortec Transvector Model No: 952. The solenoid valve is preferably an electrically operated Dema general purpose solenoid valve Model A413P, 110 V., 3/8" NPT (available from John Brooks, Canada Ltd.).
It is to be appreciated that modifications may be made to the preferred embodiments of the invention. For instance, the tint reservoir 36 may be located above the chamber 34 and the tint introduced into the spray jets 44 by gravity rather than by a siphon action. Also, other means can be used to exhaust excess tint from the reservoir instead of a vortex generator, such as a vacuum pump.
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An apparatus for producing heat set, tinted yarn. The apparatus comprises yarn heat setting means and yarn tinting means for tinting said yarn after heat setting in the yarn heat setting means. The yarn tintint means comprises a tinting chamber having openings therein to allow for passage of yarn therethrough, yarn guide means for guiding the yarn through the tinting chamber, spray nozzles locatable withinthe chamber for spraying tint onto the yarn within the chamber and means for exhausting excess tint from the chamber.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 12/344,630 filed on Dec. 29, 2008, the disclosure of which is incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not applicable.
BACKGROUND
[0003] The present disclosure relates to motorized vehicles suitable for military use and more particularly to a modular military vehicle that can be adapted for non-military uses.
[0004] A multi-purpose vehicle, suitable for military, homeland security, disaster/emergency response, and other uses, should be versatile. It should be able to protect the operators and be highly deliverable to any site, adaptable, maintainable, and agile. Also, it should be armored and operable over rugged terrain and hostile environments, including, for example, desert and frigid conditions. Such vehicle further should be highly maneuverable.
[0005] It is such a vehicle that the present disclosure is addressed.
BRIEF SUMMARY
[0006] The disclosed modular vehicle is compartmentalized through modular, severable, frangible sub-systems or components with a view to isolating effects of ballistic shock/blast and other undesirable kinetic forces.
[0007] Modularity includes a central driver module and engine module, which form a central chassis module or CCM. The driver module is capable of carrying, for example, 1 to 3 people, and can be common in design regardless of function and/or use. Pods, then, can be attached to the central module to provide different functions including, for example, troop carrier, ambulance, cargo, etc. Such design allows the army to transport pods and not fully dedicated (i.e., single use) vehicles.
[0008] The engine module bolts directly to the central driver module as a complete unit. Pods are more readily transported to other field areas of need, so long as at the new site has the means to attach/detach such pods to the CCM.
[0009] The CCM and side pods present three V-shaped hulls on their underside. Such a blast-deflecting design along with side pod frangibility and engine module open framework should significantly increase the venting of the blast reducing the penetration and deformation of the area where people are sitting. The smallest flat area facing the ground now can be less than about 10 inches (25.4 cm) in width.
[0010] Engine and gearbox together are separate and located to the rear of the driver module. This design isolates heat, noise, fumes etc., from the driver module and personnel therein significantly increasing the ability of the occupants to perform their duty when they leave the vehicle.
[0011] The relatively common cross-sectional shape of all modules allows for a design that is very simple to manufacture. The detachable rear bulkhead of the driver module and troop carrying pods allows for ease of fitting a spall liner, the shrapnel anti intrusion layer, inside the vehicle. Because of this removable bulkhead, the spall liner can be large in size improving its ability to counter intrusion of shrapnel.
[0012] With the side pods removed, the narrow engine module design allows for ease of maintenance of the engine, because of a closer proximity to the engine components by technicians working on the engine/gearbox section. It is intended that this engine module be manufactured with a tubular frame allowing significant blast venting between the two-crew side modules increasing survivability of the crew. Placing the engine/drive module in the center of the vehicle reduces the possibility of these components being damaged and disabling the vehicle with small arms fire. By simply creating small top and rear armored panels these drive elements become well protected. In summary, this engine/drive placement allows excellent blast venting and provides good small arms fire protection.
[0013] The air inlet duct is located above the vehicle and is retractable in case the vehicle needs to be transported, for example, in a marine vessel (76″ or 1.93 m) height. Locating the cooling and engine air inlet high allows for less contamination of air with dust, and when using the vehicle in hot environments this high inlet position allows the air temperature to the cooling systems to be substantially lower than using air adjacent to the road surface, etc.
[0014] The pods can be designed to swing out either in a parallel fashion or in a door fashion incorporating as well a frangible system or the pods can be attached in such a way with a 4 bar linkage the pods can merely be located to the CCM by means of the clip system later disclosed (See FIG. 6 A)—all methods can become detached by fracture of a frangible fastening device.
[0015] 4-wheel drive is achieved by passing the driveshaft under or beside the engine and personnel seated in the CCM to the differential housing located under the driver in the driver module. This may require the addition of a two or three shaft oblique transfer module that allows minimization of driveshaft angle. This oblique transfer module can be placed at the interface between the driver and engine modules.
[0016] The basic design admits of carrying from 1 to 7 people. Additional crew can be carried in additional pods at the rear of the CCM. Alternatively, the wheelbase can be lengthened, by about 30″ (106.2 cm) by extending the rear central module or the driver module. The pods similarly then can be increased and an extra person can be included in each pod; thus, increasing the total vehicle capacity to 9 people instead of 7. Increasing the wheelbase by 30″ (106.2 cm) also allows an alternate ambulance ‘low rise’ side pod to be fitted in between the wheels, allowing transportability in a 76″ (1.93 m) height. Similarly the concept can be used as a 3-person carrier by reducing the CCM front to a single person with single person pods; thus, allowing substantial carrying capacity rear of the engine area.
[0017] Each person in the vehicle further can be fitted with a helmet protective collar, such as is used in high speed automobile racing, to help reduce acceleration effects on the lower neck during an explosion. Similarly, the occupants can wear an extended rear ballistic panel (SAPI panels—small arms protection inserts) to allow for increased protection and also to act as helmet support (with straps) to avoid the possible separation of the top spinal cord in the event of extreme accelerations on the head relative to the body. This extension located behind the helmet can serve three functions. The first function is to act as a ballistic barrier for the area of the neck and upper torso. The second function is to serve as helmet support should the soldier be exposed to forces, which may serve to separate the head from the spinal cord in a vehicular accident or similar. Third, soldiers' helmets can often withstand direct rounds on the helmet, but it is desirable for there to be some means to reduce the energy the neck experiences, so that any additional support from the lower torso will help the soldier survive the impact of this round on a helmet. It is thought that this SAPI panel will be secured with Velcro® into position within the soldier's ballistic vest and with the soldiers' ballistic collar. It is thought that a pivot at the top of this extended SAPI panel should be incorporated to allow the head to be turned easily and with comfort.
[0018] For commercial or civilian (non-military) uses of the disclosed modular vehicle, their use and fuel efficiency drives many vehicle designs. Reducing the vehicle weight and/or improving the aerodynamic drag of the vehicle improve fuel efficiency of the disclosed modular vehicle.
[0019] Having removable pods will allow the user to only use the pods that are needed at that time. With the resultant weight reduction and narrow aerodynamic shape, fuel economy is improved. Typical US pickups are adaptable as multi-use vehicles carrying 4 to 5 people and cargo. The disclosed modular vehicle achieves such uses with a side-to-side split of functionality. That is, the modular vehicle has a CCM capable of carrying 2 people and which is common in all configurations. The side pods, which attach to this CCM, have different functions including, for example, carrying people in people pod on a single side or both, carrying cargo in pods that are relatively low to the ground and tall in height, sleeping pods, etc. If required, as with the military design, the commercial modular vehicle can include 4-wheel drive.
[0020] The central pod can be narrow and aerodynamic with aerodynamic suspension attachment legs and wheel aerodynamic pods to reduce drag. The rear aerodynamic pods can be removed when adding any side pod, which also will incorporate an aerodynamic covered surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a fuller understanding of the nature and advantages of the present modular vehicle, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:
[0022] FIG. 1 is an isometric view of the modular military vehicle carrying a pair of side, personnel pods and 3 cantilevered cargo pods;
[0023] FIG. 2 is a front view of the modular military vehicle of FIG. 1 ;
[0024] FIG. 2A is a simplified schematic view of the modular military vehicle of FIG. 2 showing the blast energy dissipation paths resulting from the design of the bottoms of the modules;
[0025] FIG. 3 is a side view of the modular military vehicle of FIG. 1 ;
[0026] FIG. 4 is an overhead view of the modular military vehicle of FIG. 1 ;
[0027] FIG. 5 is an underside view of the modular military vehicle of FIG. 1 ;
[0028] FIG. 6 is a front view like that in FIG. 1 with the side pods deployed;
[0029] FIG. 6A is an enlarged view of the frangible coupling system of the side pods to the CCM;
[0030] FIG. 6B is an isometric of the shock absorbed element of the frangible coupling system depicted in FIG. 6A ;
[0031] FIG. 7 is an underside view of the pod-deployed vehicle in FIG. 6 ;
[0032] FIG. 7A is an isometric view of one of the tether assemblies seen in FIG. 7 ;
[0033] FIG. 7B is a side view of the tether assembly shown in FIG. 7B ;
[0034] FIG. 8 is a side view of the modular military vehicle of FIG. 1 showing seated personnel, engine, and the like in phantom;
[0035] FIG. 9 is an isometric view of the modular military vehicle fitted with ambulance side pods;
[0036] FIG. 10 is a front view of the modular ambulance vehicle of FIG. 9 ;
[0037] FIG. 11 is a side view of the modular ambulance vehicle of FIG. 9 ;
[0038] FIG. 12 is a top view of the modular ambulance vehicle of FIG. 9 ;
[0039] FIG. 13 is a rear isometric view of the modular ambulance vehicle of FIG. 9 ;
[0040] FIG. 14 is an isometric view of the modular military vehicle with only 1 side pod, but with a rear personnel pod;
[0041] FIG. 15 is a sectional view taken along line 15 - 15 of FIG. 12 ;
[0042] FIG. 16 is an isometric view of the modular military vehicle fitted with cargo side pods;
[0043] FIG. 17 is a rear view of the modular cargo vehicle of FIG. 16 ;
[0044] FIG. 18 is an isometric view of the modular military vehicle without side pods, but fitted with top-mounted armament and a movable rear storage module;
[0045] FIG. 19 is an isometric view of the modular military vehicle fitted with side armament that includes missiles, and a rear storage module for carrying, for example, extra armament, missiles, or the like;
[0046] FIG. 20 is an isometric view of a side pod transport for conveying electrical generators and fuel drums;
[0047] FIG. 21 is an isometric view of a side pod transport configured as a storage cabinet;
[0048] FIG. 22 is an isometric side view of the modular military vehicle adapted as a fuel tanker by configuring with side and rear fuel tanks;
[0049] FIG. 23 is an isometric view of a side pod configured to convey 3 soldiers;
[0050] FIG. 24 is an isometric view of the short wheelbase modular military vehicle with a pair of single soldier side pods, a single drive CCM module and a rear shelter;
[0051] FIG. 25 is the short wheelbase shelter modular military vehicle of FIG. 24 with no soldier side pods;
[0052] FIG. 26 is an isometric view of another modular military vehicle embodiment having a one-person driver module, side pods for soldiers, and a rear cargo shelter;
[0053] FIG. 27 is an overhead view of another modular military vehicle embodiment designed only for troop transport;
[0054] FIG. 28 is a side isometric view of a standing soldier (medic from FIG. 15 ) fitted with a SAPI (small arms protection inserts) panel affixed to his helmet;
[0055] FIG. 29 is a rear view of the medic of FIG. 28 showing the back-carried SAPI unit;
[0056] FIG. 30 is a side view of the medic seated, but still wearing the extended SAPI unit;
[0057] FIG. 31 is a rear view of the seated medic of FIG. 30 ;
[0058] FIG. 32 is an isometric view of a streamlined modular passenger vehicle without side pods;
[0059] FIG. 33 is an isometric view of a streamlined modular passenger vehicle with side passenger pods;
[0060] FIG. 34 is an isometric view of a streamlined camping modular vehicle with side pods;
[0061] FIG. 35 is an isometric view of a streamlined passenger modular vehicle with cargo side pods;
[0062] FIG. 36 is an isometric view of a troop carrier embodiment of the modular military vehicle having an enlarged driver module suitable for up to, for example, 3 troops to occupy, troop side pods, and rear troop pod; and
[0063] FIG. 37 is an isometric view of a troop carrier embodiment of the modular military vehicle with enlarged driver module, troop side pods, and rear storage pod.
[0064] The drawings will be described in greater detail below. Like components will carry the same numerical identification in different drawings and embodiments.
DETAILED DESCRIPTION
[0065] The disclosed modular vehicle primarily is designed for military use. For such use, however, the modular vehicle needs to be readily transported by air (e.g., cargo plane, helicopter, etc.) to remote hostile territory; withstand explosive blasts, bullets, and like insults; be easy to maintain and repair; readily convertible for cargo use, troop transport, wounded soldier (ambulance) transport; provide cover and support for ground soldier advancement; and the like. The disclosed modular vehicle accomplishes each of these tasks and more, as the skilled artisan will appreciate based on the present disclosure. Its design flexibility further enables the disclosed modular vehicle to be adapted for passenger use, civilian ambulance use, civilian cargo use, and the like.
[0066] Referring initially to FIGS. 1-5 , a modular military vehicle, 10 , is shown to include a central chassis module or CCM, 12 (see FIG. 18 ), composed to a driver module, 14 , and an engine module, 16 . Vehicle 10 also includes two side pods, 18 and 20 , and three rear pods, 22 , 24 , and 26 . Equally these three pods could be a single pod across the rear of the vehicle. In these figures, side pods 18 and 20 carry personnel, while rear pods 22 , 24 , and 26 carry cargo. Vehicle suspension, steering, wheels/tires, transmission, headlights, windows (glass or polymer, often bullet-proof), and the like will be provided in conventional fashion adapted to the intended use of vehicle 10 . Driver module 14 and side modules 18 and 20 all are fitted with doors, such as doors, 28 and 30 , on side pod 18 , and a door, 32 , on driver module 14 , for ingress and egress of personnel. Driver module 14 is adapted for in-line front-to-back seating of two personnel with the driver entering module 14 through door 32 and the rear personnel entering module 14 via an overhead opening, 34 or through door 32 without the driver in position and the driver seat having the capacity to tilt forward. Access to cargo modules 22 , 24 , and 26 can be gained by side or rear doors, such as, for example, a side door, 36 , for module 22 . Desirably, driver module 14 has a rear bulkhead to allow for ease of building the internal elements of the module 14 .
[0067] A retractable/extendable engine air inlet, 38 , is seen in an extended position from the top of engine module 16 (two engine configuration forms shown in FIG. 1 and FIG. 9 ). Air inlet 38 can be retracted or removed. Its location atop modular vehicle 10 keeps it above much of the dust created by vehicle 10 and events occurring on the ground in the vicinity of vehicle 10 . An exhaust port, 37 , for the engine exhaust is disposed rearward of air inlet 38 or air can exit down over the engine and exit via holes at the rear of the CCM rear engine module. In one configuration, a grate, 39 , allows air to exit the engine compartment. Not only will be air be cleaner atop vehicle 10 , but it will be cooler than air next to or underneath vehicle 10 particularly when in a hot environment. Such air inlet and exhaust ports also could be located in the sides of engine module 16 close to the top and these same benefits realized. For present purposes, the air inlet and/or exhaust ports are located “about the top” of the engine module by being located in the top of the module or in a side of the module very close to the top thereof.
[0068] The bottoms of each module can be designed with upward slanting sides to aid in deflecting any blasts occurring from underneath modular military vehicle 10 to minimize damage. A blast energy dissipation pattern, 1 , (see FIG. 2A ) for driver module 14 ; a blast energy dissipation pattern, 2 , for side module 18 ; and a blast energy dissipation pattern, 3 , for side module 20 , show the blast energy being diverted around the sides of the modules to lessen damage to the components of vehicle 10 . Such pattern along with side modules 18 and 20 that can be controllably blown away from CCM 12 will help in minimizing vehicle damage from blasts occurring underneath virtually any area beneath vehicle 10 .
[0069] Referring now to FIGS. 6 and 7 , side pods 18 and 20 are seen in partially deployed condition up and away from CCM 12 using hydraulic pistons and supporting strut assemblies, 40 and 42 , which are conventional in design and operation. Deployment of side pods 18 and 20 enjoys several advantages, including, inter alia, reducing the footprint size subject to road explosions, adding increasing distance from ground blasts, isolating pods subject to damage from blasts and explosions, and providing foot soldier protection between the side pods and CCM 12 (potentially with platforms that deploy for the soldiers to stand on upon deployment of the side pods). The blast deflecting bottom design also is seen to include a small horizontal flat or V bottom with angled flat sections that extend upwards. Such design presents a minimal footprint to explosions. The slanted sections and space created between the deployed side pods and CCM 12 deflect the brunt of the explosive force upwards away from the vehicle to minimize damage. The modular design permits any damaged pod to be readily replaced in the field and the vehicle put back in operation.
[0070] It should be observed that the hydraulic system for deploying the side pods or modules also could be adapted to move the side pods from an operating position adjacent to the CCM to the ground for removing the side pods and from the ground to an operating position. Thus, the hydraulic system could be adapted for putting on and taking off the side pods from the DMACS.
[0071] In the event of an explosion, the troop side pod coupling to the central element is “frangible”, permitting the side pod to be dislodged by the explosion. It is thought that, to absorb some of the energy of the blast explosion, it is possible that a damper can be placed between the side pod and the CCM as part of the frangible system. The addition of this dampening mechanism may allow the pod to still remain attached to the CCM without breaking the frangible coupling.
[0072] With reference to FIGS. 6A , 6 B, and 7 , side module 18 is illustrated affixed to engine module 16 using an interlocking bracket assembly, 201 , a cylinder assembly, 203 , and a tether assembly, 43 . Together, these items make up the frangible coupling of the central element to the side module. Interlocking bracket assembly 201 is composed of a pair of “L” brackets, 213 and 215 , which are retained in interlocked relationship by gravity. Additionally, attenuating assembly 203 (such as a cylinder assembly) is composed of a cylinder, 205 , associated bracket, 207 , a handle, 213 , and interfitting rod, 209 , and associated bracket, 211 . Hooking a side module to the CCM is quick and easy by dint of the design of the frangible coupling assembly. Handle 213 is rotatable to cause pressure from cylinder 205 to be exerted on inserted rod 209 . This ensures that the side module will stay attached during travel, such as, for example, over rough roads. The force of a blast, however, will cause rod 209 to withdraw from cylinder 205 and the tethers will limit the distance of travel of the dislodged module.
[0073] The troop side pod also can be retained to the CCM by means of tether assemblies (see also FIGS. 7A and 7B ), 41 and 43 , whose ends are retained on both the CCM and the side pod by brackets, 45 and 47 . The straps, 49 , most likely will be in the form of webbing having a degree of elasticity and stitched together in a snaked or accordion pattern so that when the pod moves away from the CCM the stitching is broken as the tether unfolds.
[0074] The frangible coupling assembly and tether, then, are able to further absorb some of the explosion energy during an explosion, say, beneath the vehicle. In particular, the cylinder assembly pulls apart with some force as is typical for a cylinder and rod assembly, and by the ether stretching in much the same way that seat belts absorb energy during an accident. Here, however, in order for the pods not to decelerate too violently at the end of the straps, most likely some elasticity will be incorporated into the straps. As shown in FIGS. 7 , 7 A, and 7 B, at least one pair of straps (for example, 3 pairs per side module) can used for each side pod. This number is arbitrary and could be greater or lesser in number.
[0075] Personnel, 44 and 46 , seated in driver module 14 are seen in FIG. 8 . Also seen is an engine, 48 , a radiator, 50 , and a exhaust assembly, 52 . Air for engine 48 and to cool radiator 50 is admitted through grate 38 . Exhaust passed through exhaust assembly 52 passes to the atmosphere through port 37 . Fresh air for personnel 44 and 46 is admitted via air inlets 38 on each side of the CCM above the engine ( FIG. 14 rectangular hole above engine module 16 ). As observed earlier, locating the air inlets and exhaust atop vehicle 10 will minimize dust entry into vehicle 10 . A presently preferred engine/radiator configuration, however, is illustrated in FIG. 14 .
[0076] In FIGS. 9-13 , litter pods, 52 and 54 , have been attached to CCM 12 to create a modular ambulance. CCM 12 remains unchanged from the previous drawings, except for an air intake, 38 ′, and exhaust, 37 ′. Litter pods 52 and 54 may or may not be deployable. Litter pod 52 is fitted with a door, 56 , while litter pod 54 also is fitted with a door, 58 (see FIG. 13 ). Medic personnel can enter litter pods 52 and 54 through doors 56 and 58 . Wounded soldiers can be placed in litter pods 52 and 54 conveniently through rear access openings in litter pods 52 and 54 , such as is illustrated in FIG. 13 . Doors, netting, or other restrictions will be provided to keep the litters in litter pods 52 and 54 . In FIG. 15 , a medic, 60 , is seen in medic pod 52 where he can attend to the needs of wounded soldiers on litters, 68 and 70 , or can be seated on a seat, 62 . A storage bin, 64 , is provided to house medicines, instruments, and like items.
[0077] Medic 60 is fitted a SAPI panel, 61 , affixed to his helmet, 63 . Personnel 44 and 46 seated in driver module 14 also could be fitted with a SAPI panel, as, indeed, could any personnel confined within military module vehicle 10 . FIGS. 28-31 illustrate medic 60 again, standing and sitting. SAPI panel 61 is seen affixed to helmet 63 in addition to medic 60 , regardless of whether in a seated or standing position. Such extended panel 61 from the SAPI pack will be secured with, for example, Velcro® into position within the soldier's ballistic vest and with the soldiers' ballistic collar. It is thought that a pivot at the top of this extended SAPI panel should be incorporated to allow the head to be turned easily and with comfort.
[0078] Since the narrow aspect of litter pods 52 and 54 permit medic to easily only treat the upper torso and head of the wounded soldier, module 24 is a personnel module for carrying an additional medic, 72 , which can treat the legs and lower torso of the wounded soldiers. In order to accomplish such treatment, an access, 74 , is created in module 24 that mates with a similar access, 76 , in module 52 . Similar accesses are provided for medic 72 to treat wounded soldiers in module 54 .
[0079] CCM 12 is illustrated in FIG. 18 . In this embodiment a portable missile launcher, 96 , is disposed atop driver module 14 and is desirably controlled by personnel 46 , so that driver 44 can concentrate on driving CCM 12 . Module 24 is mounted on rails, such as a rail, 25 , and another rail on the far side of CCM 12 that is not seen in FIG. 18 . Moving module 24 rearwardly away from CCM 12 also permits repair/maintenance access to the engine in engine module 16 and to the transmission and other drive train elements disposed therein. A cover conveniently at the rear of CCM 12 , for example, could be opened to provide such servicing access.
[0080] That CCM 12 can be operated as a stand-alone vehicle is an advantage of the design disclosed herein. For that reason, CCM 12 and all disclosed modules can be manufactured from aluminum or composite material for weight reduction. Also, a layer “up armor” can be provided as a ballistic layer from a variety of composite materials presently used to shield military vehicles. When the side modules/pods are attached, they provide additional shielding for CCM 12 and drive components from being struck by ballistic impact.
[0081] Virtually all surfaces of all modules are designed to be manufactured from relatively flat, planar material (stressed skin), which contributes to reduced manufacturing costs. From the front, a narrow profile is presented, thus reducing the area vulnerable to being struck by bullets, shrapnel, or the like. Aligning personnel in a single row permits such narrow front profile. Similarly having each occupant in a narrow pod allows the effective use of side curtain and front air bags deployed in the event of a blast or accident. Basically being able to encase the occupants between inflated air bags and the seat should increase their likelihood of survival during a blast or accident. It is likely that to save weight, since the crew side pods are not required to carry any vehicle loads, their weight can be reduced allowing additional vehicle payload capacity.
[0082] Engine 48 can be any internal combustion engine powered by gasoline, diesel fuel, or the like, optionally turbocharged or supercharged; or can be a turbine engine; or any other power plant designed to propel vehicle 10 . While the suspension is conventional for this type of vehicle, independent suspension is advantageous. Sufficient room underneath the driver module permits a driveshaft to pass there beneath to provide 4-wheel or all-wheel drive for vehicle 10 . It is possible that the vehicle also could incorporate an alternative drive system like electric or hydraulic.
[0083] FIG. 19 illustrates a mobile missile launcher version, 100 , of the deformable modular armored combat vehicle disclosed herein. In particular, a pair of side missile pods, 102 and 104 , is affixed on either side of a CCM, 106 . Personnel located within CCM 106 can control missile launch and target, or the target can be fed into an onboard computer remotely, say, for example, from air or ground reconnaissance. A rear storage module, 108 , can convey spare missiles, for example or additional armament, such as, for example, an air-to-ground or air-to-air, or anti-tank, etc., missile. Armament, such as missiles, may require elevation to clear the CCM during firing.
[0084] FIG. 20 shows an additional side pod, 110 , for transforming the modular combat vehicle into a mobile generator unit, conveying fuel drums, 112 , 114 , and 116 ; along with generators, 118 and 120 . One or two such mobile generator side pods enable power to be brought into remote field or other locations.
[0085] FIG. 21 shows another cargo side pod, 121 . One or two of such side pods can be carried by the CCM. Again, the user can use almost any combination of pods on the CCM for extreme flexibility and utility.
[0086] FIG. 22 illustrates a fuel tanker, 122 , where fuel tanks are the side pods. In particular, upper side pods, 124 and 126 , have upper rear access for fuel. A pair of lower fuel pods, 128 and 130 (not seen), can be in fuel connection with upper fuel pods 124 and 126 , or separately accessible.
[0087] FIG. 23 illustrates yet another troop side pod, 132 , for conveying 3 soldiers per side pod. Again, one or both side pods could be the 3-troop versions.
[0088] FIG. 24 illustrates a military vehicle, 140 , configured with a short wheelbase, so as to accommodate only a single soldier (driver) in a CCM, 142 . Side pods, 144 and 146 , carry but a single soldier. Military vehicle 140 , then, carries only 3 soldiers. At the rear, is a shelter, 148 , for transport into the field (e.g., combat zone). FIG. 25 illustrates vehicle 140 without side pods. An engine module, 150 , is revealed in greater detail.
[0089] FIG. 26 illustrates a military vehicle having a driver module, 151 , seating only the driver. A pair of side modules, 153 and 155 , are attached to an engine module, 157 . Shelter 148 is carried at the rear of the vehicle.
[0090] The design flexibility of the disclosed modular military vehicle is enveloped in FIG. 27 . A troop transport only modular military vehicle, 161 , is illustrated. In order to increase the troop capacity, a driver module, 163 , has been widened behind the driver in order to accommodate additional instruments, material, goods, etc. Side troop modules, 165 and 167 , accommodate another 2 soldiers each and are carried by an engine module, 169 . Finally, a rear troop module, 171 , accommodates another 6 soldiers. The total troop capacity of module military vehicle 161 is 11 troops. Additionally with widening the driver module slightly an additional 2 crew can be seated behind the driver as is represented in FIG. 30 . This, then, would take the crew carrying capacity of this configuration to 13.
[0091] FIG. 36 expands upon the embodiment in FIG. 27 for a modular military vehicle, 300 , which has an expanded driver module, 302 , which has been widened for accommodating a driver in the forward position and 2 soldiers seated side-by-side behind the driver for a total of 3 troops in driver module 302 . Side modules or side pods, 304 and 306 , are troop pods adapted for 2 soldiers to be seated in each module. A rear module, 308 , also can seat 3 soldiers. A spare tire, 310 , is shown affixed to the side of rear module 308 . FIG. 37 depicts the same basic vehicle 300 , except that rear troop module 308 has been replaced with a cargo or armament module, 312 . In both embodiment of vehicle 300 , an overhead hatch, is located in the roof of driver module 302 for permitting a soldier to rise up for providing cover fire using rifle or other armament.
[0092] Commercial or civilian (non-military) versions of the modular vehicle are illustrated in FIGS. 32-35 . In particular, a civilian modular vehicle, 200 , is seen to be streamlined in design, but again using the in-line seating design to present a narrow head-on profile for vehicle 200 . The rear module contains the engine, with a possible storage disposed behind the engine.
[0093] In FIG. 33 , side modules, 202 and 204 , are hung onto the sides of vehicle 200 . Entry for passengers in pods can be gained though doors, 206 and 208 , placed in side module 208 . Similar doors can be provided for side module 202 and for the driver. A camping version, 210 , is illustrated in FIG. 34 , where camp stretcher modules 212 and 214 (fitted with skylights), are hung onto the sides of vehicle 200 . In this embodiment, the sides of vehicle 200 will be open to side modules 212 and 214 in order to provide such treatment.
[0094] A “pickup” version of the disclosed modular vehicle is illustrated in FIG. 35 where a side storage module, 216 , is carried on one side of vehicle 200 and entry/exit doors are provided on the side opposite for ingress and egress of people into vehicle 200 . Again, depending upon the design goals, a rear storage module can be carried at the rear of vehicle 200 .
[0095] While the apparatus has been described with reference to various embodiments, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope and essence of the disclosure. Additionally, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure may not be limited to the particular embodiments disclosed, but that the disclosure will include all embodiments falling within the scope of the appended claims. In this application the US measurement system is used, unless otherwise expressly indicated. Also, all citations referred to herein are expressly incorporated herein by reference.
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A modular, wheeled vehicle suitable for military use, includes a driver module having a width for seating one person and having length for seating a second (and optional third) person therebehind, and an engine module disposed behind the driver module containing an engine for powering the modular vehicle. The engine module has a rear surface adapted to receive a storage module. The driver module and the engine module form a central element having a pair of sides, a bottom, and a top. The central element is adapted to receive the modules on both of the central element sides. The central element has air inlet for personnel and for the engine disposed atop the central element. The bottom of the central element and troop side pods generally are V-shaped with slanted, upward extending sides.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to light sensors, and more particularly to integrating light systems that provide an indication of the total amount of light sensed over a predetermined time interval.
2. Description of the Prior Art
Various light sensing systems, including integrating systems, are known; however, systems capable of operating at low light levels typically require preamplifiers between the light sensing device and the integrating amplifier. Such preamplifiers are disadvantageous in that they have offset and drift problems that must be compensated, thereby resulting in a fairly complex and expensive design. In addition, systems that use a dual-slope integrator for integrating the output of the sensor generally require switching circuitry for alternately connecting and disconnecting the sensor from the integrator. Such switching devices further add to the complexity of the system and cause further drift and voltage offset problems.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a sensor-integrator that overcomes many of the disadvantages of the prior art sensor-integrators.
It is another object of the present invention to provide a simplified sensor-integrator.
It is still another object of the present invention to provide a sensor-integrator using a dual-slope integrator that does not require switching circuitry for disconnecting the sensor from the dual-slope integrator.
It is yet another object of the present invention to provide a sensor-integrator system wherein the sensor is connected directly to the inputs of the integrator.
In accordance with a preferred embodiment of the invention, an operational amplifier is connected as a dual-slope integrator with a storage capacitor coupled between the output and the inverting input of the amplifier. The sensor which may be, for example, a light sensing semiconductor diode, is connected directly between the input terminals of the amplifier. A reference current source is connected to the inverting input and a switch is provided for selectively rendering the reference current source operative to apply the reference current to the inverting input. A timing circuit is provided for maintaining the reference current source inoperative for a predetermined first time interval. During this time interval, the storage capacitor is charged to a level proportional to the amount of current flowing through the sensor, and consequently, to a level proportional to the amount of light sensed by the sensor. After the predetermined first time interval has elapsed, the reference current source is rendered operative to apply the reference current to the operational amplifier in a direction opposite that of the current provided by the sensor to thereby discharge the storage capacitor. A comparator is provided again to disable the reference current source after the storage capacitor has been discharged to a predetermined level. The time required to discharge the storage capacitor to the predetermined level is a function of the integral of the current provided by the sensor over the first predetermined time interval.
BRIEF DESCRIPTION OF THE DRAWING
These and other objects and advantages of the present invention will become readily apparent upon consideration of the following detailed description and attached drawing, wherein:
FIG. 1 is a simplified schematic diagram of the sensor-integrator according to the invention;
FIG. 2 is a graph illustrating the operation of the sensor-integrator according to the invention; and
FIG. 3 is a schematic diagram of a practical embodiment of the sensor-integrator according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing, with particular attention to FIG. 1, there is shown a simplified diagram of the sensor-integrator 10. The sensor-integrator 10 comprises an operational amplifier 12 having inverting and noninverting input terminals. A sensor such as a photodiode 14 is connected, in the present embodiment, directly across the input terminals of the amplifier 12, however, any passive direct current coupling network, such as, for example, a resistive or inductive network, can be used. A capacitor 16 is connected between the output and the inverting input of the operational amplifier 12 and stores a charge proportional to the amount of current flowing through node 11. A pair of resistors 18 and 20 connected to a voltage reference provide a source of reference current for the integrator 10. A switch 22 selectively shunts the reference current flowing through the resistor 18 to ground and away from the amplifier 12, while a second switch 24 is used to discharge the capacitor 16.
In operation, the switch 22 is first closed to shunt the reference current away from the inputs of the amplifier 12. The switch 24 is momentarily closed to discharge the capacitor 16. After the switch 24 is opened, the input current at node 11 is solely the current generated by the photodiode 14. Since the input voltage at the inverting inputs of amplifier 12 is essentially zero potenial, because the feedback mechanism of the integrator, the diode load is a low impedance, and for all practical purposes a short circuit. The diode 14 thus acts as a current generator that provides a current proportional to light intensity. This current will be referred to as i 1 . The direction of the current i 1 is shown in FIG. 1, with the flow of conventional current being from the inverting input of the amplifier 12 through the diode 14 and into the noninverting input of the amplifier 12. Because resistor 20 is connected to essentially a zero potential source at each termination, the resistor 20 provides virtually no shunting of the diode generated current. Thus, with the switch 22 closed, the shunting effect of the resistor 20 is negligible. Also, with the switch 22 closed, the reference current i 2 is zero.
The current i 1 flows through the capacitor 16 in the direction shown in FIG. 1. This current causes the capacitor 16 to charge and gradually increases the output voltage e o as shown in FIG. 2. Thus, the voltage e o increases at a rate determined by the current i 1 . The switch 22 is maintained closed for a predetermined time interval t 1 at which point the switch 22 is opened. When the switch 22 is opened, the current i 2 increases from a zero value to a reference value greater than the value of the current i 1 . When this occurs, the current i through the capacitor 16 becomes equal to the difference between the currents i 1 and i 2 since the direction of the current i 2 is opposite that of the current i 1 . Since, as previously stated, the value of the current i 2 is greater than the value of the current i 1 , the direction of the net current i flowing through the capacitor 16 becomes opposite to the direction shown in FIG. 1, and the voltage e o decreases at a rate determined by the value of the reference current i 2 minus i 1 . Alternatively, the sensor current i 1 can be made a known value by illuminating the diode 14 with a light source of known intensity, or by maintaining the diode 14 in total darkness.
After the switch 22 has been opened, the voltage e o will continue to drop at a rate determined by the reference current i 2 minus i 1 . The switch 22 is maintained open until the output voltage e o reaches a predetermined level, such as, for example, zero volts, and the time t 2 elapsed between the opening of the switch 22 and the value of the output voltage e o reaching the aforesaid predetermined level is ascertained. Since the value of the output voltage e o at the end of the time interval t 1 is determined by the magnitude of the sensor current i 1 , and since the magnitude of the reference voltage i 2 is known, the value of the sensor current i 1 can be readily ascertained by comparing the time intervals t 1 and t 2 in conventional dual-slope integrator fashion.
A practical embodiment of the sensor-integrator according to the invention is illustrated in FIG. 3. The embodiment illustrated in FIG. 3 utilizes hundreds series reference numerals to identify various components, with analogous components of the embodiments of FIGS. 1 and 3 having like tens and units digits. Thus, the amplifier 112, for example, corresponds to the amplifier 12 of FIG. 1.
In the embodiment illustrated in FIG. 3, the amplifier 112, the diode 114, the capacitor 116 and the resistors 118 and 120 correspond to the like components 12, 14, 16, 18 and 20 of FIG. 1. In addition, a field effect transistor 122 is used as the switch 22, and a pair of field effect transistors 123 and 125 are connected in series to form a switching circuit 124 analogous to the switch 24. Two field effect transistors are used as the switching circuit 124 to reduce the leakage current across the capacitor 116, and a resistor 127 at the junction of the transistors 123 and 125 serves as a current limiting resistor. In the embodiment shown, the field effect transistors 122 and 123 are N-channel enhancement mode insulated gate field effect transistors (IGFETS) and the field effect transistor 125 is a P-channel junction transistor (J-FET), however, any suitable switching transistors may be used.
In the embodiment illustrated in FIG. 3, the operation of the circuit is controlled by a logic circuit 126 which contains timing, computation and switching circuitry. In operation, the logic circuit 126 applies a signal via a line 128 to the gate of the field effect transistor 122 to thereby render the field effect transistor 122 conductive. This causes the transistor 122 to conduct to ground the current flowing through the resistor 118 as a result of the potential at the junction of a pair of resistors 130 and 132. Simultaneously, the field effect transistors 123 and 125 are momentarily rendered conductive via signals applied to the gates thereof via a pair of lines 134 and 136. The signal on line 136 is applied to the transistor 125 via a reverse polarity protection diode 138. The momentary rendering conductive of the transistors 123 and 125 discharges the capacitor 116 to initialize the integrating operation.
The transistor 122 is maintained conductive for the predetermined time interval t 1 during which time the capacitor 116 is charged to a value proportional to the current generated by the photodiode 114, which current is proportional to the intensity of the light to which the photodiode 114 is exposed. After the time interval t 1 , the logic circuit 126 initiates a timing sequence and renders the transistor 122 nonconductive. When the transistor 122 is rendered nonconductive, current flows from the junction of the resistors 130 and 132 through the resistors 118 and 120 and into node 111 of the amplifier 112. This current reverses the polarity of the output current and causes the gradual discharge of the capacitor 116 and the corresponding decrease in the voltage at the output of the amplifier 112.
The output of the amplifier 112 is monitored by a comparator 140 which compares the voltage at the output of the amplifier 112 with a bias voltage appearing at the junction of a pair of resistors 142 and 144, and provides a signal to the logic circuit 126 when the voltage at the output of the amplifier .[.116.]. .Iadd.112 .Iaddend.drops below the voltage at the junction of the resistors 142 and 144 to thereby terminate the timing sequence. A resistor 146 connected between the comparator 140 and the junction of the input of the comparator 140, the capacitor 116 and the transistor 125 provides hysteresis for the comparator 140. The elapsed time t 2 between the rendering nonconductive of the transistor 122 and the generation of the logic signal by the comparator 140 is then compared with the predetermined time interval t 1 in order to determine the current generated by the photodiode 114 during the interval t 1 .
In the two embodiments illustrated in FIGS. 1 and 3, the source of reference current has been a voltage source and a pair of limiting resistors. However, the reference current can be obtained from various current sources including a second photodiode that is exposed to a light source which would produce a current greater than the maximum current produced by the diode 14. Such an arrangement would provide compensation for variations in the light source and compensate for variations in the parameters of the photodiode 14.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described above.
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A sensor-integrator utilizes a light sensing diode directly connected to the inputs of an operational amplifier. The operational amplifier forms part of a dual-slope integrator and directly integrates the current generated by the light sensing diode thereby eliminating the need for preamplifiers and diode switching circuitry.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Provisional Application No. 61/139,510, entitled A SYSTEM AND METHOD FOR PRODUCING A SECURE DOCUMENT USING TONER-BASED IMAGING, filed Dec. 19, 2008, the entire disclosure being incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to compositions, systems, and methods for printing documents. More particularly, the invention relates to an improved coating composition for printing documents in a secure manner, such that the documents are difficult to forge and original versions of the documents are readily verifiable, and to a system including the coating composition and to methods of using and making the coating composition.
BACKGROUND OF THE INVENTION
[0003] Toner-based imaging, which generally involves forming an electrostatic or magnetic image on a charged or magnetized photoconductive plate or drum, brushing the plate or drum with charged or magnetized toner, transferring the image onto a substrate such as paper, and fusing the toner onto the substrate using heat, pressure, and/or a solvent, can be used to form relatively inexpensive images on a surface of a substrate.
[0004] Because toner-based imaging, such as printing, is a relatively quick and inexpensive technique for producing copies of images, the technique is often employed to produce documents that were traditionally formed using other forms of printing or imaging-e.g., impact printing or ink-jet printing. For example, in recent years, toner-based imaging has been employed to produce financial documents, such as personal checks, stocks, and bank notes; legal documents such as wills and deeds; medical documents such as drug prescriptions and doctors' orders; and the like. Unfortunately, because the image is formed on the surface of the substrate, documents produced using toner-based imaging techniques may be relatively easy to forge and/or duplicate.
[0005] Various techniques for printing or forming secure documents have been developed over the years. For example, U.S. Pat. No. 5,124,217, issued to Gruber et al. on Jun. 23, 1992, discloses a secure printing toner for electrophotographic processing. This toner, when exposed to a solvent such as toluene, often used in document forgery, produces a color stain indicative of the attempted forgery. This toner is only useful to disclose an attempted forgery when a particular solvent is used to remove a portion of a printed image. Thus, the toner cannot be used to mitigate copying of the document or forgery by adding material to the document.
[0006] U.S. Pat. No. 5,714,291, issued to Marinello et al. on Feb. 3, 1998, discloses another toner that includes submicron ultraviolet sensitive particles. An authenticity of the document can be verified using an ultra-violet scanner. Requiring use of an ultra-violet scanner is generally undesirable because it adds cost to a forgery analysis and requires additional equipment.
[0007] Other techniques for producing secure images include modifying the paper onto which the image is printed. Such modified papers may include paper having a low-ink-absorption coating and paper including crushable micro capsules that contain leuco ink and a color acceptor. Although techniques including these forms of paper work relatively well for impact-type printing or copying, the techniques would not work well in connection with toner-based or similar printing methods.
[0008] Other techniques for producing secure images include providing special paper coatings to increase smudge resistance of an image created by an electrostatic process. However, the coatings generally do not affect an ability to add material to the document or authenticate the originality of the document.
[0009] For the foregoing reasons, improved compositions, methods and apparatus for forming secure documents using toner-based processing, which are relatively easy and inexpensive, are desired.
SUMMARY OF THE INVENTION
[0010] The present invention provides an improved coating composition, system and method for producing secure documents. Various ways in which the present invention addresses the drawbacks of the prior art are addressed below. In general, however, the coating composition, system, and method of the present invention produce images that are difficult to alter and that are relatively easy to assess whether an alteration to the image has been attempted or made.
[0011] In accordance with various embodiments of the invention, a system includes a substrate, a toner that includes a colorant and a dye applied to a surface of the substrate, and a primary migration-enhancing coating. In accordance with various aspects of these embodiments, the system further includes a secondary migration-enhancing coating. The secondary coating may be configured as a barrier between the first coating and other substrates and/or to minimize effects of different substrates. In accordance with further aspects of these embodiments, the toner is applied using a laser printer. And, in accordance with yet additional aspects, the primary migration-enhancing coating and/or secondary migration-enhancing coating is applied using an offset printing process. As discussed in more detail below, using an offset printer to apply the primary and/or secondary migration-enhancing coating allows for application of the coating(s) to select areas of the substrate-within the registration of the printer.
[0012] In accordance with additional embodiments of the invention, a coating composition, e.g., a composition for application of a primary migration-enhancing coating, used for producing secure images, includes an oil, a resin, an anti-misting agent, and an anti-offsetting agent. In accordance with various exemplary aspects, the primary coating composition is configured for application to a substrate using offset printing.
[0013] In accordance with yet additional embodiments of the invention, a coating composition, e.g., a composition for application of a secondary migration-enhancing coating, includes a high viscosity oil with low surface tension and an anti-misting agent. In accordance with various aspects of these embodiments, the secondary migration-enhancing coating composition includes a plurality of oils. In accordance with further exemplary aspects, the secondary coating composition is configured for application to a substrate using offset printing.
[0014] In accordance with yet further embodiments of the invention, a method of forming a secure document includes the steps of providing a substrate, applying a colorant and a dye to the substrate, and applying a primary migration-enhancing coating to the substrate using an offset printing (e.g., offset lithography) process. In accordance with various aspects of these embodiments, the process further includes the step of applying a secondary migration-enhancing coating. In accordance with further aspects, the secondary migration-enhancing coating is applied using offset printing techniques. As set forth in more detail below, the colorant and dye and the primary and secondary migration-enhancing coatings may be applied to the same surface of the substrate, or the colorant and dye may be applied to a first surface of the substrate and the primary and/or secondary migration-enhancing coatings may be applied to a second surface of the substrate.
[0015] In accordance with additional embodiments of the invention, a method of forming a secure document includes the steps of providing a substrate, applying a colorant and dye to the substrate, applying a primary migration-enhancing coating to the substrate, and applying a secondary migration-enhancing coating overlying the primary migration-enhancing coating. In accordance with various aspects of these embodiments, the primary migration-enhancing coating is applied using offset printing techniques. In accordance with further aspects, the secondary migration-enhancing coating is applied using offset printing techniques.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] A more complete understanding of the present invention may be derived by referring to the detailed description and claims, considered in connection with the figures, wherein like reference numbers refer to similar elements throughout the figures, and:
[0017] FIG. 1 illustrates a secure document system in accordance with various embodiments of the invention;
[0018] FIG. 2 illustrates an offset printing station for use with various embodiments of the invention; and
[0019] FIG. 3 illustrates an offset printing apparatus, including multiple stations, for use with various embodiments of the invention.
[0020] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
DETAILED DESCRIPTION
[0021] The following description is provided to enable a person skilled in the art to make and use the invention and sets forth the best mode contemplated by the inventors of carrying out their invention. Various modifications to the description, however, will remain readily apparent to those skilled in the art, since the general principles of a coating composition, system, and method for forming secure images on a document have been defined herein.
[0022] The present invention may be used in connection with a variety of printing processes, and is particularly well suited for toner and offset printing applications. The following description describes a coating composition, system, and method to produce secure documents using toner and lithographic offset processes. However, the invention is not limited to such composition, system, or process.
[0023] Exemplary coatings and systems in accordance with various embodiments of the invention may be used for a variety of purposes, such as to produce financial documents, such as personal checks, stocks, and bank notes; legal documents such as birth certificates, drivers' licenses, wills, and deeds; medical documents such as drug prescriptions, transcripts, and doctors' orders; educational documents, such as transcripts and records, and the like.
[0024] FIG. 1 illustrates a system 100 , which includes a substrate 102 , a toner 104 , a first or primary migration-enhancing coating 106 , a second or secondary migration-enhancing coating 108 , and a dye 110 . Although system 100 is illustrated with multiple coatings, as discussed in greater detail below, systems in accordance with alternative embodiments may include only a single coating or layer, wherein the single coating may include the attributes of one or both coatings 106 and 108 . Furthermore, although coatings 106 , 108 are illustrated as being directly opposite toner 104 on a second surface 114 of substrate 102 , coatings 106 and/or 108 could alternatively be disposed on the same surface as and underlying toner 104 .
[0025] Toner 104 and dye 110 function together with coatings 106 and 108 to provide a first image using toner 104 on a first surface 112 of substrate 102 and a latent image with dye 110 that may be visible from first surface 112 and/or second surface 114 . In accordance with various embodiments of the invention, the secure image systems (e.g., system 100 ) are difficult to forge and copies of the secure images are easily detected, because any mismatch between the printed image and the latent image indicates an alteration or attempted alteration and a missing latent image is indicative of a copy of the document.
[0026] System 100 may be formed by applying a toner and a dye onto substrate 102 using, for example, an electrostatic or electrophotographic process, such as a laser printing process and applying coating 106 and/or coating 108 using an offset printing process (e.g., a lithographic process). Using an offset printing process to apply coatings 106 and/or 108 is advantageous because it allows the coating to be applied relatively inexpensively and, if desired, allows for precise application of the coatings only to desired areas of the substrate-within the precision of the register of the lithographic printer. In accordance with one embodiment of the invention, toner 104 and dye 110 are printed onto a first surface of a substrate and one or more coatings 106 , 108 are applied onto a second surface of the substrate. In accordance with alternative embodiments, coatings 106 , 108 may be applied onto a first surface of the substrate and subsequently a toner-based image may be printed on top of the coating(s).
[0027] FIG. 2 illustrates a station and FIG. 3 illustrates an apparatus including multiple stations for application of coating 106 and/or 108 using offset printing, in accordance with various embodiments of the invention. Exemplary station 200 includes an ink or composition transfer system 202 , a damping station 204 , a plate cylinder 206 , an offset cylinder 208 , and an impression cylinder 210 .
[0028] In accordance with various embodiments of the invention, during operation of station 200 , a coating (e.g., coating 106 ) is applied to a substrate 220 , such as paper, by first applying water from system 204 , and then a coating composition from system 202 , onto cylinder 206 , using roller 216 and rollers 212 - 214 , respectively. The coating composition and the water are immiscible, such that the water repels the coating composition from the non-image areas of cylinder 206 and the coating composition is applied to image areas of cylinder 206 . The coating composition from cylinder 206 is then transferred to offset cylinder 208 , which in turn, is used to transfer the coating composition to substrate 220 . Coating 108 may be applied in the same manner. As noted above, applying coating compositions in this manner allows for very precise application of the coating compositions, which may be desirable to, for example, reduce an amount of coating material used to form system 100 and to mitigate unwanted diffusion of dye 110 .
[0029] Apparatus 300 may be used to provide multiple images and/or coatings to a substrate using offset techniques. Apparatus 300 includes multiple stations 302 , 304 , and 306 , each station generally including an ink or coating composition transfer system 202 to transfer an image or coating composition onto a substrate. By way of example, an image can be transferred to a substrate (e.g., substrate 102 ) using station 302 . Station 304 is then used to apply layer or coating 106 onto substrate 102 . Coating 106 may be applied substantially in register with and on an opposite surface with toner 104 , as illustrated, or underlying toner 104 . Similarly, if used, coating 108 can be applied overlying coating 106 .
[0030] Referring back to FIG. 1 , in accordance with various embodiments of the invention, substrate 102 may include any suitable material onto which an image can be transferred. Exemplary substrate 102 materials include paper (e.g., 20 lb. MOCR bond paper), and other substrates suitable for offset lithographic printing.
[0031] Toner 104 may include any suitable composition capable of printing an image on a surface of substrate 102 . In accordance with various embodiments of the invention, toner 104 includes a thermoplastic binder resin, a colorant, a charge-controlling agent, and a migrating dye 110 . Each of the thermoplastic binder resin, the colorant, release agent, and the charge-controlling agent may be the same as those used in typical toners. The toner may be a one-component toner or a multiple-component toner (e.g., toner and developer).
[0032] The thermoplastic binder resin helps fuse the toner to the substrate. In accordance with one embodiment of the invention, the binder resin has a melt index of between about 1 g/10 min. and 50 g/10 min. at 125° C. and has a glass transition temperature between about 50° C. and about 65° C. Exemplary materials suitable for the thermoplastic binder resin include polyester resins, styrene copolymers and/or homopolymers—e.g., styrene acrylates, methacrylates, styrene-butadiene-epoxy resins, latex-based resins, and the like. By way of particular example, the thermoplastic binder resin is a styrene butadiene copolymer sold by Eliokem as Pliolite S5A resin.
[0033] The colorant for use with toner 102 can be any colorant used for electrophotographic image processing, such as iron oxide, other magnetite materials, carbon black, manganese dioxide, copper oxide, and aniline black. In accordance with one particular example, the colorant is iron oxide sold by Rockwood Pigments as Mapico Black.
[0034] The charge-control agent helps maintain a desired charge within the toner to facilitate transfer of the image from, for example, an electrostatic drum, to the substrate. In accordance with one embodiment of the invention, the charge control agent includes negatively-charged control compounds that are metal-loaded or metal-free complex salts, such as copper phthalocyanine pigments, aluminum complex salts, quaternary fluoro-ammonium salts, chromium complex salt type axo dyes, chromic complex salt, and calix arene compounds.
[0035] The toner may also include a releasing agent such as a wax. The releasing agent may include low molecular weight polyolefins or derivatives thereof, such as polypropylene wax or polyethylene wax or a copolymer of polypropylene wax and polyethylene wax.
[0036] Preferred dyes in accordance with the present invention exhibit a strong color absorbance through a substrate (e.g., substrate 102 ), good solubility in a migration fluid, good stability, and dissolve and/or migrate in polar and/or non-polar solvents used to attempt document forgery—e.g., by attempting to remove an image from the top surface of the substrate. Exemplary polar solvents used in such attempted forgery include acetone, methanol, methyl ethyl ketone, and ethyl acetate; exemplary non-polar solvents include toluene, mineral spirits, gasoline, chloroform, heptane, and diethyl ether. In addition, the dyes are preferably indelible.
[0037] Exemplary soluble dyes, suitable for use as dye 110 , include phenazine, stilbene, nitroso, triarylmethane, diarlymethane, cyanine, perylene, tartrazine, xanthene, azo, disazo, triphenylmethane, fluorane, anthraquinone, pyrazolone quinoline, and phthalocyanine. In accordance with one embodiment of the invention, the dye is red in color and is formed of xanthene, sold under the name Baso Red 546. In accordance with another embodiment of the invention, the dye is red in color and is formed of disazo, and sold under the name Bright Red LX-598. In accordance with yet another embodiment of the invention, the dye is blue in color and is formed of anthraquinone, sold under the name Bright Blue LX-9224. Other color dyes of similar chemical structure are also suitable for use with this invention.
[0038] Coating 106 includes a migration-enhancing agent configured to assist dye 110 to migrate through at least a portion of substrate 102 . In accordance with various embodiments of the invention, coating 106 includes an oil as a migration-enhancing agent, a resin, and an anti-misting agent, such as silica, bentonite clay, kaolin, titanium dioxide, or any combination thereof. The anti-misting agent mitigates unwanted spray of coating material. The oil may be a single-component oil or include multiple components, such as oils, platisizers, liquid polymers, and combinations thereof. By way of example, the oil may include one or more of the following compounds: benzyl butyl phthalate, bis (2-ethylhexyl) adipate, trioctyl trimellitate, and 2,2,4-trimethyl-1,3-pentanediol diiosbutryate. The resin may be a phenolic modified rosin ester or other resin compound, yielding high viscosity (e.g., greater than about 70,000 cp) and low tack and low misting properties, such as Sylvaprint 87-85 available from Arizona Chemical.
[0039] In accordance with various aspects of these embodiments, coating 106 includes an anti-offsetting agent, such as silica, pea starch, wheat starch, silicone oil, a wax, or any combination thereof. The wax may be a synthetic wax, such as fluorocarbon wax, polyethylene, polypropulene, combinations thereof, or a natural wax, such as carnauba wax, or a combination of natural and synthetic waxes. In accordance with further aspects, a particle size of the anti-offsetting agent may range from about 0.2 microns to about 25 microns.
[0040] In accordance with further embodiments of the invention, a composition for application of coating 106 (e.g., a composition of a solution for station 202 ) includes about 25% to about 90%, about 35% to about 80%, or about 45% to about 75% oil; about 10% to about 60%, or about 20% to about 50%, or about 25% to about 45% resin; and about 0.1% to about 10%, or about 0.02% to about 5%, or about 0.05% to about 2% anti-misting agent. In accordance with various aspects of these embodiments, the composition includes about 0.1% to about 10%, or about 0.2% to about 5%, or about 0.5% to about 2% anti-offsetting agent and various combinations of these compounds. All percents set forth herein are in weight percent unless otherwise noted.
[0041] The following non-limiting examples illustrate various combinations of materials and processes useful in forming a composition in accordance with various embodiments of the invention. These examples are merely illustrative, and it is not intended that the invention be limited to these illustrative examples.
EXAMPLE 1
[0042]
[0000]
Material
Amount
Oil
64%
Resin
33%
Silica
1%
Pea Starch
1%
[0043] A composition for coating 106 was prepared by first heating a stirred mixture of the oil and the silica (e.g., Syloid Rad 2105 available from Grace Davidson) until a temperature of about 250° F. was reached. While continuing to increase the temperature of the mixture, the resin was slowly added to the mixture. After all the resin has been added and the temperature had reached about 320° F. and had not exceeded about 360° F., the mixture is held at about 360° F. until all of the resin is dissolved. The mixture was then allowed to cool to a temperature below about 135° F., and then the pea starch was added. The mixture was mixed until the pea starch (e.g., pea starch available from Nutri-Pea Limited) was fully dispersed.
[0044] After the mixture had cooled to about 70° F., the viscosity of the mixture was measured with a falling rod viscometer. The viscosity of the composition at about 70° F. was between about 40,090 cps and 95,000 cps. The coating was applied to the paper with an offset press (e.g., using station 202 ). The amount of coating applied was in the range of about 0.3 mg/sq. inch to about 4 mg/sq. inch.
EXAMPLE 2
[0045]
[0000]
Material
Amount,
Oil
64%
Resin
33%
Silica
1%
Wax
1%
[0046] Another composition for application of coating 106 was prepared by first heating a stirred mixture of the oil, the wax, and the silica until a temperature of about 250° F. was reached. While continuing to increase the temperature of the mixture, the resin was slowly added to the mixture. After all the resin had been added and the temperature had reached about 320° F. but had not exceeded 360° F., the mixture was held at about 360° F. until all of the resin was dissolved. The mixture was mixed until the pea starch was fully dispersed.
[0047] After the mixture had cooled to about 70° F., the viscosity of the mixture was measured with a falling rod viscometer. An exemplary viscosity was between about 40,000 cps and 95,000 cps at about 70° F. The coating was applied to the paper with an offset press. The amount of coating applied was in the range of about 0.3 mg/sq. inch to about 4 mg/sq. inch.
EXAMPLE 3
[0048]
[0000]
Material
Amount, %
Oil
64%
Resin
33%
Silica
1%
Wax
1%
[0049] Yet another composition for application of coating 106 was prepared by first heating a stirred mixture of the oil, the wax and the silica until a temperature of about 250° F. was reached. The silica was a large particle size silica (e.g., about 9.0 microns) such as Sylysia 380, available from Fuji Sylysia Chemical Ltd. While continuing to increase the temperature of the mixture, the resin was slowly added to the mixture.
[0050] After all the resin had been added and the temperature had reached about 320° F. but not exceeded 360° F., the mixture was held at about 360° F. until all of the resin dissolved. The mixture was allowed to mix until the pea starch was fully dispersed.
[0051] After the mixture had cooled to about 70° F., the viscosity of the mixture was measured with a falling rod viscometer. An exemplary viscosity is between about 40,000 cps and 95,000 cps at about 70° F. The coating was applied to the paper with an offset press. The amount of coating applied was in the range of about 0.3 mg/sq. inch to about 4 mg/sq. inch.
[0052] As noted above, systems in accordance with various embodiments of the invention include a secondary migration-enhancing coating 108 , which may be applied overlying coating 106 . In accordance with various aspects, the composition for forming coating 108 includes a high viscosity oil (e.g., viscosity about or greater than about 100,000 cp) having a low surface tension and an anti-misting agent. The oil may be a single oil (e.g., a high-viscosity silicone oil) or a combination of oils (e.g., silicone oils) having different viscosities, such that the final viscosity of the composition is suitable for offset printing. The anti-misting agent may include any of the anti-misting agents noted above.
[0053] In accordance with further embodiments of the invention, a composition for application of coating 108 (e.g., a composition of a solution for station 202 ) includes about 70% to about 99.9%, about 85% to about 99.5%, or about 95% to about 99% of a first silicone fluid; and about 0.1% to about 30%, or about 0.2% to about 15%, or about 0.5% to about 2% silica. In accordance with various aspects of these embodiments, the composition includes about 0% to about 50%, or about 10% to about 30%, or about 15% to about 25% of a second silicone fluid. Exemplary first silicone fluids include moderately-high (10,000+5000 cp) to high viscosity (about 100,000 cp) di-methyl silicones fluids, and exemplary second silicone fluids include extremely high (about 1 million cp) viscosity di-methyl silicones fluids.
[0054] The following examples illustrate various compositions that may be used to form coating 108 using, e.g., an offset printer.
EXAMPLE 4
[0055]
[0000]
Material
Amount
Silicone Fluid
99%
Silica
1%
[0056] A secondary migration-enhancing coating according to this example was made by weighing a desired amount of high viscosity silicone oil such as a di-methyl silicone (e.g., DM Fluid 100,000, sold by Shin-Etsu Chemical) and a five micron silica powder into a vessel equipped with a stirrer. The solution was stirred until a uniform dispersion was obtained. The mixture can be heated to facilitate the mixing. After the mixture was well dispersed and cooled, the viscosity was measured. An exemplary viscosity range for the composition is between about 54,000 cps and about 100,000 cps at a temperature of about 70° F. The coating was applied via an offset printing press utilizing a station subsequent to the station used to apply coating 106 . The amount of coating applied was in the range of about 0.2 mg/sq. inch to about 6 mg/sq. inch.
EXAMPLE 5
[0057]
[0000]
Material
Amount
Extremely High Viscosity Silicone Fluid
25%
Moderately High Viscosity Silicone Fluid
74%
Silica
1%
[0058] A secondary migration-enhancing coating according to this example was made by weighing a desired amount of extremely high viscosity silicone oil such as a di-methyl silicone (e.g., oil having a viscosity of about 1 million cp or more, such as DM Fluid 1,000,000, sold by Shin-Etsu Chemical), moderately high viscosity silicone oil, such as a lower molecular weight di-methyl silicone (e.g., oil having a viscosity of about 10,000±5000 cp, such as DM Fluid 10,000, sold by Shin-Etsu Chemical), and a five micron silica powder into a vessel equipped with a stirrer. The solution was stirred until a uniform dispersion was obtained. The mixture can be heated to facilitate the mixing. After the mixture was well dispersed and cooled, the viscosity was measured. An exemplary viscosity range for the composition was between about 54,000 cps and about 100,000 cps at about 70° F. The coating was applied via an offset printing press utilizing a station subsequent to the station used to apply coating 106 . The amount of coating applied was in the range of about 0.2 mg/sq. inch to about 6 mg/sq. inch.
[0059] Documents using the aforementioned coated substrates were printed in combination with the security toner described above using a Hewlett Packard Laserjet 4250 printer. Initially, the resulting image had high optical density, high resolution with no noticeable background, and no migration of the visible red dye was apparent. Within 24 hours, areas of printed toner were removed from the surface of the paper and it was observed that red residual images had started to work into the paper. Within 72 hours of printing, an indelible image became visible on the non-printed side of the paper. This measurement can be qualified by measuring the reflective optical density difference between the image on the second surface of the substrate and the non-image area on the second surface of the substrate. In accordance with various exemplary embodiments of the invention, an optical density difference of at least 0.07 optical density units measured 72 hours after the first side of the substrate has been printed with a laser printer is observed.
[0060] Although the present invention is set forth herein in the context of the appended drawing figures, it should be appreciated that the invention is not limited to the specific form shown. For example, while the invention is conveniently described in connection with electrostatic printing and offset printing, the invention is not so limited; the toner of the present invention may be used in connection with other forms of printing-such as iongraphic, magnetographic, and similar imaging techniques. Various other modifications, variations, and enhancements in the design and arrangement of the composition, method, and system set forth herein may be made without departing from the spirit and scope of the present invention as set forth in the appended claims.
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A coating composition, system, and method for printing documents that are difficult to chemically or physically forge and that are easy to visually verify are disclosed. The system includes a substrate, a toner, including a colorant and a dye, a primary migration-enhancing coating applied using an offset printing process and optionally a secondary migration-enhancing coating applied using an offset printing process. An image formed using the toner of the invention is readily verified by comparing a colorant-formed image and a dye-formed image. In addition, if a solvent is used in an attempt to alter the printed image on the substrate, the dye migrates or diffuses to indicate tampering with the document.
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This application is a national stage completion of PCT/FR2003/002381 filed Jul. 28, 2003 which claims priority from French Application Serial No. 02/10029 filed Aug. 6, 2002.
FIELD OF THE INVENTION
The present invention concerns an interlacing device for a machine which palletizes elongated products, as well as a palletizing machine equipped with such a device, said palletizing machine comprising at least one gantry, one carrier moving in vertical translation along said gantry, and a gripping device moving in horizontal translation along said carrier, designed to remove said products from a storage ramp and place them on the transport pallet.
BACKGROUND OF THE INVENTION
Palletizing machines of this type for automatically or semi-automatically palletizing elongated products are well known, for example, machines to palletize cylindrical tubes directly and continuously as they exit the production line. Palletizing tubes is a delicate operation because when they are arranged side by side and in superimposed layers, they have a tendency to roll on top of each other. This problem can be resolved by interlacing the rows of tubes using a tie which may be a string, a ribbon, a strap, a band, a fabric strip, a film or other equivalent means made of fiber, wire, natural and/or synthetic material, said tie being woven, non-woven, extruded, or manufactured by any other method, and the function of said tie being to maintain the rows in place and prevent the tubes from falling before the pallet is encircled. This interlacing is usually done manually by an operator who must place the spool or spools of tie material on either side of the pallet as the rows advance. Since the tubes may reach up to ten feet in length, if they are very long the number of spools of interlacing required will double, necessitating more than one operator.
Publication No. WO 02/06121 by the same applicant describes a palletizing machine equipped with an interlacing device for automatically interlacing tubes while they are being palletized. This interlacing device comprises two supports located on either side of the transport pallet and designed to alternately receive one or more spools of interlacing material. This device also comprises a gripping means located on the device which grips the tubes or located on an additional gripping device, designed to displace the spool or spools of interlacing material from one support to the other while the rows of tubes placed upon the transport pallet are advancing. Since this interlacing device is integral with the palletizing machine, it does not offer an optimal industrial solution. Actually, if the gripping means are located on the tube gripping device, it is necessary to interrupt the palletizing cycle to move the spool of interlacing material from one support to the other, which has a negative impact on the global output of the palletizing machine. If the gripping means are located on a gripping device that is supplemental to the tube gripping device, manufacturing the interlacing device becomes complex and has a negative impact on the global cost of the palletizing machine.
U.S. Pat. No. 5,769,601 proposes an interlacing device that is integrated with a palletizing machine and operating in the reverse manner of the machine that is the object of the invention. The tubes are moved to the upper portion of the machine by a conveyor and pushed onto a pallet by cylinders, forming a row. After each row, the pallet descends one level to permit formation of a new row. A winder moving in perpendicular translation to said tubes unfurls a strip of paper or plastic film between the rows of tubes to maintain them in place. This interlacing device is not transferable to the palletizing machine of the invention and does not permit interlacing of long tubes.
SUMMARY OF THE INVENTION
The goal of the present invention is to remedy these disadvantages by proposing an economical interlacing device which can function concurrently with the palletizing machine, thereby eliminating reduced output, and which is suitable for use with any length of tube.
This goal is achieved by an interlacing device such as the one defined in the preamble and characterized in that it comprises at least one interlacing gantry designed to extend essentially parallel to said products along at least a portion of their length, said interlacing gantry comprising at least one guide supplied by at least one spool of interlacing material, and said interlacing device also comprising drive means coupled with said interlacing gantry which alternately displace the gantry between at least two end positions so as to displace said guide in at least one interlacing plane essentially perpendicular to said palletized products alternately from one side of said transport pallet to the other.
The said drive means may be designed to cause the interlacing gantry to move in at least one alternating pivoting motion and/or at least one alternating translation motion.
The drive means may be selected from the group comprising at least electric motors, hydraulic and pneumatic cylinders. Depending upon the drive means selected, they may also comprise at least one transmission system selected from the group comprising at least chain and pinion, pulleys and belts.
In a preferred embodiment, the interlacing device comprises at least one chassis integrating the guide means which guide said interlacing gantry translationally, said guide means consisting of at least one pathway formed in the chassis to receive rollers integral with the vertical posts on said interlacing gantry.
Advantageously, the interlacing device comprises at least two guides located on the interlacing gantry for distributing at least two interlacing ties in at least two essentially parallel interlacing planes distributed along said palletized products.
According to one variation, at least one of the guides is associated with activation means which alternately displace it in translation along said interlacing gantry for a predetermined distance in order to displace said corresponding interlacing plane essentially parallel to itself, said activating means being selected from the group comprising at least electric motors, hydraulic and pneumatic cylinders.
This goal is further achieved by a palletizing machine such as that defined in the preamble and characterized in that it comprises at least one interlacing device such as the one defined above.
In the preferred form of embodiment, the interlacing device comprises at least one interlacing gantry with dimensions that allow it to be integrated inside the gantry of the palletizing machine below the gripping device and outside the transport pallet and the palletized products.
This gripping device advantageously comprises means for controlling its drive means, associated with the means for controlling said palletizing machine, to displace said interlacing gantry alternately from one side of the transport pallet to the other, essentially parallel to the interlacing planes, as the products are being placed on said transport pallet and according to a predetermined interlacing pattern.
According to one variation, at least one of the guides on the interlacing device is associated with activating means designed to displace it in alternate translation along said interlacing gantry for a predetermined distance so as to displace said corresponding interlacing plane essentially parallel to itself.
In this case the control means are designed to control this activation means so as to wrap said interlacing material around the posts on said pallet while product palletizing progresses and in the predetermined interlacing pattern.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention and its advantages will be better understood from the following description of various embodiments given by way of non-limiting example and with reference to the attached drawings, wherein:
FIG. 1 is a surface view of the palletizing machine equipped with an interlacing device according to the invention;
FIG. 2 is a surface view of only the interlacing device;
FIG. 3 is a side view of the interlacing device of FIG. 2 shown in its two end positions;
FIGS. 4A and 4B are side views of the palletizing machine of FIG. 1 with the interlacing device in the two end positions of FIG. 3 , respectively;
FIG. 5 shows one example of interlacing tubes superimposed in layers on a pallet;
FIGS. 6 and 7 are side views and top views of one variation of the interlacing device of the invention; and
FIG. 8 is a detailed view of a guide-wire of the variation of FIGS. 6 and 7
DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawings, interlacing device 10 , 10 ′ according to the invention is designed to equip a machine 1 for palletizing elongated products, for example, cylindrical tubes 2 varying in length from approximately 1 to 10 meters.
This palletizing machine 1 is usually, but not necessarily, located at the end of a continuous production line for tubes 2 and allows them to be automatically or semi-automatically palletized, using a continuous or discontinuous method. For this purpose, it comprises a gantry 3 to which is attached a carrier 4 which can move in vertical translation. At least one griping device 5 with claws, air vents, or other adaptation is attached to said carrier 4 in horizontal translation and is designed to remove tubes 2 located side by side in parallel on an inclined storage ramp 6 and deposit them side by side in parallel on at least one transport pallet 7 or any other fixed or movable support. In the example shown, gripping device 5 consists of a gripping girder 5 extending along the entire length of tubes 2 , said gripping girder 5 being equipped with air vents 5 ′ allowing it to carry tubes 2 using suction. Likewise, in the example shown, transport pallet 7 is supported by a movable carrier 8 , but may also be located between fixed and/or removable upright posts.
The automatic operation of this palletizing machine 1 is ensured by a control means advantageously comprising a computer which directs the various displacements of carrier 4 and gripping girder 5 to obtain the optimum kinematics and cycle of operation. This operating cycle is summarized below with reference to FIGS. 4A and 4B :
1. displacement of gripping girder 5 from the left side of gantry 3 and descent of carrier 4 to remove the tube or tubes 2 from storage ramp 6 ;
2. ascent of carrier 4 and then displacement of gripping girder 5 from the right side of gantry 3 for a longer or shorter distance, as determined by the progression of rows of tubes 2 positioned on transport pallet 7 ;
3. descent of carrier 4 to deposit the tube or tubes 2 on transport pallet 7 or on the last row of tubes 2 positioned on this pallet;
4. ascent of carrier 4 to begin another cycle.
An interlacing device 10 is associated with palletizing machine 1 and is designed to effect automatic interlacing of rows of tubes 2 on transport pallet 7 , ensuring that the tubes and the rows remain in their relative positions.
With reference to FIGS. 1 through 5 , said interlacing device 10 comprises at least one interlacing gantry 11 extending essentially parallel to tubes 2 along either a portion or the entire length thereof and becoming integrated within the interior of gantry 3 of palletizing machine 1 . Specifically, interlacing gantry 11 must be displaceable inside palletizing machine 1 below gripping girder 5 and perpendicular to palletized tubes 2 . This interlacing gantry 11 consists specifically of two vertical upright posts 11 a joined at the top by a horizontal cross beam 11 b and two struts 11 c. If it is formed of a single portion, it extends for the entire length of tubes 2 . Depending upon the length of tubes 2 , it may be divided into two portions, each of which extends at the most halfway across tubes 2 . This interlacing gantry 11 is supplied on one side or on two sides by one or more interlacing spools 12 located either in a bobbin-carrying case 13 on the interlacing gantry 11 as in FIG. 2 , on the floor as in FIG. 1 , on a bobbin-carrying rack (not shown) or on any other equivalent movable or fixed support.
This interlacing gantry 11 is designed to be alternately movable in at least one direction essentially perpendicular to tubes 2 between at least two end positions located essentially on either side of transport pallet 7 . This alternating movement allows interlacing spool or spools 12 to unwind in interlacing planes P that are essentially parallel to each other and perpendicular to tubes 2 . This alternating movement may consist of pivoting around a low point or translational movement along a course C as in the example shown. Interlacing device 10 comprises for this purpose a drive mechanism 14 which may consist of an electric motor 15 and a gear and chain transmission 16 or pulley and belt or other equivalent system. The drive mechanism 14 may also consist of a system of hydraulic or pneumatic cylinders or any other equivalent system. Interlacing gantry 11 is translationally guided by the appropriate guide means comprising, for example, rollers 17 , such as guide wheels, circulating within at least one pathway 18 provided in chassis 19 , or some other equivalent means. Rollers 17 are provided on each vertical post 11 a on the interlacing gantry to guide it accurately. Chassis 19 , in the example shown, consists of two elongated bases 19 ′ that are essentially parallel, adjustable in height at the bottom and distributed at each extremity of interlacing gantry 11 to guide each vertical post 11 a. A third base 19 ′ is provided in a median area of the interlacing gantry 11 to transmit the drive force of electric motor 15 on the other side of interlacing gantry 11 through a transmission box and transmission axles so as to also ensure that the two vertical posts 11 a on interlacing gantry 11 are driven simultaneously.
Interlacing gantry 11 also comprises guides 20 to guide and separate interlacing ties 12 ′ unwinding from spool 12 . Depending upon the type of interlacing 12 ′ used (wire, band, sheet, film), these guides may be adapted. In the example shown, interlacing tie 12 ′ is a wire product and guides 20 are guide-wires, the term used throughout the remainder of the description. These guide-wires 20 may consist, for example, of guide wheels, eyelets, combs, or other equivalent guide-wire, used alone or in combination. These guide-wires 20 may be passive or active, that is, drive in rotation, for example, as with the guide wheels. They are positioned in several places, such as, for example, on posts 11 a near the starting point of interlacing ties 12 ′, on cross beam 11 b at each departure point of the interlacing tie 12 ′, in the corner of gantry 11 to direct interlacing ties 12 , etc., and their position can be regulated. Guide-wires 20 of cross beam 11 b are positioned in interlacing planes P defined for each type and length of tubes 2 . With tubes 2 of short length, about 1 to 3 meters, interlacing takes place in the two end zones. With longer tubes, interlacing must take place in the two end zones and in one or two median zones as in the example in FIG. 1 . For this reason, interlacing device 10 must be supplied by a number of spools 12 of interlacing material that is equivalent to the number of interlacing planes P. As a function of the number of spools 12 , interlacing gantry 11 can be supplied from two sides. When spools 12 are empty, they must be replaced by full spools 12 . The end of spools 12 can be indexed in different ways by taking account of either its weight or the length of interlacing material 12 ′. This data is introduced into the computer controlling interlacing device 10 so that it produces a visual or auditory signal when the end of the spool is detected, warning the operator to exchange the empty spool for a full spool. Joining the end of spool 12 which is used up with the beginning of spool 12 can be done manually or automatically using a knotting device or other equivalent means.
Interlacing device 10 comprises either its own control means or a control means integrated into palletizing machine 1 . In both cases, these control means are dependent upon the operation of palletizing machine 1 so as to displace interlacing gantry 11 automatically and alternately from one side to the other of transport pallet 7 as the rows of tubes 2 are deposited on this transport pallet 7 and according to a predetermined interlacing pattern, one example of which is shown in FIG. 5 .
How this interlacing pattern is accomplished is explained with reference to FIGS. 4A and 4B . In these drawings, interlacing gantry 11 is shown in its two end positions: its departure position is shown by a dotted line and its arrival position by a solid line. In addition, in these drawings, girder 5 for gripping tubes 2 is shown in two positions: an upper position by a solid line and a lower position by a dotted line. Said gripping girder 5 comprises three air vent systems 5 ′ allowing it to carry a maximum of three tubes 2 .
At the beginning of a palletizing cycle, interlacing gantry 11 is displaced from the left to the right of transport pallet 7 (cf. FIG. 4B ) to place interlacing ties 12 ′ on pallet 7 , letting the ends overhang so knots can be tied at the end of the palletizing process. A first row of eight tubes 2 is deposited on pallet 7 while placing interlacing tie 12 ′ on transport pallet 7 . This first row may be formed by a first and a second series S 1 , S 2 of three tubes 2 and then a third series S 3 of two tubes 2 deposited side by side. Interlacing gantry 11 is displaced from the right to the left of transport pallet 7 (cf. FIG. 4A ) before a fourth and a fifth series S 4 , S 5 of three tubes 2 is deposited sided by side in a quincuncial arrangement in the first row. Interlacing gantry 11 is moved back to the right of transport pallet 7 before a sixth series S 6 of three tubes 2 is deposited in a quincuncial arrangement beside the fifth series S 5 to form the second row of tubes 2 . The formation of rows of superimposed tubes 2 combined with the insertion of interlacing ties 12 ′ continues in this way until the desired height is reached. Of course the number of rows depends on the weight and dimensions of tubes 2 . Finally, when the last series Sn of tubes 2 has been deposited to complete the last row, interlacing gantry 11 is returned to the left of transport pallet 7 . The operator cuts interlacing material 12 ′ and then removes movable chassis 8 in order to position another movable chassis 8 in front of gantry 3 to begin another palletization cycle. The use of a movable chassis 8 reduces the interruption between two palletizing cycles by some seconds and prevents tubes 2 from accumulating at storage ramp 6 . The operator can then finish knotting the ends of interlacing tie 12 ′ in order to evacuate transport pallet 7 of tubes 2 using a stacking device or some other means. Obviously, it is possible to automate the process of evacuating full movable carrier 8 and replacing it with an empty movable carrier 8 .
In certain applications interlacing can be improved or reinforced by winding interlacing material 12 ′ around posts 7 ′ that extend vertically, for example, from the four corners of pallet 7 . FIGS. 6 through 8 illustrate a variation of an embodiment of interlacing device 10 ′ allowing this specific type of interlacing to take place. Guide-wires 20 ′ provided on interlacing gantry 11 ′ are associated with activating means 21 which displaces them in alternate translation AV/AR along this interlacing gantry 11 ′ on a predetermined course D. The activating means 21 shown in the example in FIG. 8 consists of dual hydraulic or pneumatic cylinders driven by the control means for interlacing gantry 10 ′ or for palletizing machine 1 . In this embodiment, carrier 1 holding gripping device 5 comprises supplemental pieces called pushers 5 ″ extending vertically, the role of which is to push interlacing material 12 ′ downward along posts 7 ′. These pushers 5 ″ may be fixed or driven to move in alternating vertical translation using cylinders, for example.
The operation of this interlacing device 10 ′ is explained with reference to FIGS. 6 and 7 . The tubes 2 to be palletized, their length and the interlacing pattern selected determine how interlacing material 12 ′ will encircle posts 7 ′ in order to connect tubes 2 to pallet 7 .
At the outset of a palletizing cycle, interlacing gantry 11 ′ is displaced from the right to the left of transport pallet 7 on its course C to deposit interlacing material 12 ′ on pallet 7 , leaving the ends overhanging in order to be able to knot them at the end of the palletizing process. Four rows of tubes 2 are deposited on pallet 7 in a quincuncial pattern by gripping device 5 . Interlacing gantry 11 ′ is displaced from the left to the right of transport pallet 7 and guide-wires 20 ′ are displaced in translation AR before a series of six tubes 2 is deposited. Interlacing gantry 11 ′ is moved back to the left of transport pallet 7 and guide-wires 20 ′ are displaced in translation AV before a series of six tubes 2 is deposited beside the preceding one to form the fifth row of tubes 2 . Interlacing gantry 11 ′ is displaced to the right closing the loop in the interlacing material 12 ′ formed around opposing posts 7 ′. Three other rows of tubes 2 are deposited in a quincuncial pattern before interlacing gantry 11 ′ is displaced to the left and guide wires 20 ′ are displaced in translation AR to form another loop around posts 7 ′. The formation of superimposed rows of tubes 2 combined with insertion of interlacing material 12 ′ continues in this way until the desire height is reached. Obviously the number of rows depends upon the weight and dimensions of tubes 2 . To end the interlacing process, the operator knots the ends of interlacing material 12 ′. In the example in FIG. 7 , interlacing material 12 ′ is wound in a loop around opposing posts 7 ′. It could, of course, be wound in another pattern, for example, a figure eight.
It is clearly apparent from this description that the invention achieves its stated objectives, that is, effecting the interlacing of rows of tubes 2 concurrently with the palletizing process, automatically, in an optimal and economic fashion. Moreover, interlacing device 10 of the invention can be adapted to any length of tube 2 as well as to any existing automatic palletizing machine 1 that operates on the same principle.
Obviously, the present invention is not limited to the exemplary embodiments described, but extends to any modification and variation obvious to a person skilled in the art.
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The invention relates to an interlacing device which can be used automatically to interlace long products on a transport pallet in an economical and optimum manner, which can be adapted to tubes of any length and which operates concurrently with the palletizing machine. The inventive interlacing device ( 10 ) is characterized in that it comprises at least one interlacing gantry ( 11 ) which extends parallel to the palletized products along at least part of the length thereof and which comprises at least one wire guide ( 20 ), the wire guide being fed by at least one interlacing ( 12 ′) link reel ( 12 ). The aforementioned interlacing device ( 10 ) also comprises drive means ( 14 ) which are connected to the interlacing gantry ( 11 ) in order to move same alternatively between at least two end positions such as to move the guide wire ( 20 ) alternatively from one side of the transport pallet ( 7 ) to the other in at least one interlacing plane (P) which is essentially perpendicular to the palletized products ( 2 ). The invention is suitable for palletizing any long product, e.g. cylindrical tubes.
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BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to the pressure used to operate the plunger in a parison mold, and more particularly to a dwell time control system and method for automatically adjusting the selection and timing of a sequence of pressures used to drive the plunger during the parison forming process.
Glass containers are made in a manufacturing process that has three parts, namely the batch house, the hot end, and the cold end. The batch house is where the raw materials for glass (typically including sand, soda ash, limestone, cullet (crushed, recycled glass), and other raw materials) are prepared and mixed into batches. The hot end begins with a furnace, in which the batched materials are melted into molten glass, and from which a stream of molten glass flows.
The molten glass is cut into cylinders of glass called gobs, which fall by gravity into blank molds, sometimes referred to as parison molds. In the blank molds, a pre-container referred to as a parison is formed, typically by using a metal plunger to push the glass into the blank mold, or alternately by blowing the glass from below into the blank mold. The parison is inverted and transferred to a mold, where it is blown out into the shape of the container. An annealing process performed in an annealing oven or Lehr heats the containers and then slowly and evenly cools them over an extended time period to prevent them from having weakened glass caused by stresses caused by uneven cooling. The equipment at the cold end of the glass container manufacturing process inspects the containers to ensure that they are of acceptable quality.
The present invention is concerned with the parison formation process using a plunger to push the glass into the blank mold. Parisons are molded in a blank mold in an inverted position. The blank mold has two halves, and completing the finish portion are two neck ring molds located below the blank mold halves, with an upwardly oriented plunger extending through the neck ring halves and into the bottom of the blank mold halves. The blank mold halves are open at the tops thereof, and a gob of molten glass drops through this opening into the blank mold halves. A baffle is placed on top of the blank mold halves to close the opening at the top thereof, and the plunger is raised to force the gob to fill the entire cavity defined by the blank mold halves, the neck ring halves, and the baffle, thereby forming the parison. Upon completion of the cycle, the baffle is removed and the mold halves open, with the neck ring halves then transporting the parison to the blow molds.
Plunger contact time or dwell time is a particularly important parameter when producing in a narrow neck press and blow glass container manufacturing process or in a press and blow production in general. The full contact of the plunger with the glass in the gob that occurs during plunger contact or dwell time influences the characteristics of parisons produced for use in further steps in the glass container forming process. While dwell time depends on a number of parameters including friction in the movement of the plunger and glass temperature, it can also be strongly influenced by the pressure driving the plunger in its upward motion.
The plunger was formerly driven by a hydraulic system, as shown for example in U.S. Pat. No. 4,662,923, to Vajda et al. and U.S. Pat. No. 4,867,778, to Pinkerton et al., both of which are assigned to the assignee of the present patent application, and both of which are hereby incorporated herein by reference in their entirety. Both of these patents used feedback to monitor the position of the plunger and to use plunger position information to control the parison formation process to improve parison uniformity and quality.
In order to reduce the risk of fire associated with the use of hydraulic fluid in the operation of the plunger and other system components, pneumatic systems using compressed air were adopted, as illustrated in European Patent No. 0691940, to Plater et al., and in U.S. Pat. No. 5,800,590, to Pilskar, both of which are assigned to the assignee of the present patent application, and both of which are hereby incorporated herein by reference in their entirety. The '940 patent used a proportional control valve operated by a microcontroller dependent upon position and pressure feedback signals from the plunger drive piston and cylinder. The '590 patent used an initial higher pressure for a short time followed by a succeeding lower pressure that was approximately 70% of the initial higher pressure to operate the plunger.
The operation of the plunger was further refined by controlling the movement of the plunger, as illustrated in U.S. Pat. No. 6,050,172, to Schwegler et al., and in U.S. Pat. No. 7,290,406, to Anheyer, both of which are assigned to the assignee of the present patent application, and both of which are hereby incorporated herein by reference in their entirety. The '172 patent controls the timing of valves providing compressed air to both sides of a piston driving the plunger, and the '406 patent provides a feedback control system for driving the plunger at desired speeds.
After comparing the determined value with the desired dwell time, past closed loop controller increased or decreased the pressure for driving up the plunger until the resulting dwell time corresponds to the desired dwell time value has been achieved. However, simply increasing the pressure for plunger movement resulted in bottle defects, especially during dwell time. An alternative solution was moving the plunger up with different pressures (high, medium, low). However, this alternative presented problems in selecting when to switch from a higher to a lower pressure.
An illustration of such a problem is found in European Patent No. 1466871, to Krumme, which is hereby incorporated herein by reference in its entirety, describes a method of operating the plunger that somewhat varies the teachings of the '590 patent to have second and third different lower pressures following an initial higher pressure to operate the plunger. The second pressure is controlled to bring the plunger to completely fill the cavity defined by the mold halves, the neck ring halves, and the baffle at a fixed time at which point a fixed pressing time at the third pressure begins, which third pressure may be less than (in the primary embodiment) or greater than (in an alternate embodiment) the second pressure. Thus, the duration of the applications of the first and third pressures is predetermined (meaning that the duration of the second pressure is also predetermined since the overall machine is operating at a predetermined speed), with the only variable being selecting the second pressure to be sufficient to completely fill the cavity by the end of application of the second pressure.
A key deficiency of the '871 patent is that the detection of the point at which the plunger has completely filled the cavity is made by detecting that the plunger has reached a predefined position rather than actually detecting when the plunger has completely filled the cavity (see paragraph 0012 and Claim 2 of the '871 patent). Measuring the position of the plunger may be performed, for example, using the device disclosed in U.S. Pat. No. 6,185,829, to Geisel, which is hereby incorporated herein by reference in its entirety. Further, since the first pressure is only maintained for a short period of time, the operation of the plunger with the second pressure must be sufficiently high to reach the predefined position in the required time period, but not so high that it will drive open the mold halves (see the last sentence in paragraph 0010 of the '871 patent). This is a compromise that necessarily cannot result in optimizing system performance. Due to the difficulties associated with multi-pressure pressing, most glass container manufacturing plants still press with only a single pressure level that is sufficiently low to prevent the related defects, but also certainly less than an optimal solution.
It is accordingly desirable that the present invention provide an improved dwell time control method and system that results in the ability to control the dwell time (the time that the plunger is in full contact with the parison). It is also desirable that the improved dwell time control method and system automate the pressure switching process without requiring operator input once the process has been initiated. It is further desirable that the dwell time control method and system prevent the inadvertent opening of molds due to the occurrence of overpressure situations.
The dwell time control method and system of the present invention must also be of construction which is both durable and long lasting, and it should also require little or no maintenance to be provided by the user throughout its operating lifetime. In order to enhance the market appeal of the dwell time control method and system of the present invention, it should also be of inexpensive construction to thereby afford it the broadest possible market. Finally, it is also an objective that all of the aforesaid advantages of the dwell time control method and system of the present invention be achievable without incurring any substantial relative disadvantage.
SUMMARY OF THE INVENTION
The disadvantages and limitations of the background art discussed above are overcome by the present invention. With this invention, the operation of the plunger is controlled to optimize the dwell time of the plunger in contact with the parison. It results in the ability to fully automate the pressure switching process without requiring operator input once the process has been initiated. It also prevents the blank molds from being inadvertently forced open due to the occurrence of overpressure situations in the operation of the plunger.
The dwell time control method and system of the present invention uses three consecutive pressures to operate the plunger to form the parison from the glass gob in the blank mold. The total time for operating the plunger to form the parison is predefined and unchangeable time period since it is established by the operational cycle timing of the I.S. machine, so the timings that are variable are the time that the pressure is changed from the first pressure to the second pressure, and the time that the second pressure is changed to the third pressure. The dwell time control method and system of the present invention bases these times on the observed press curve from one or more previous parison forming cycles.
The timing of two characteristics of the observed press curve from one or more previous parison forming cycles are determined: the time at which the upper part of the mold becomes filled with glass from the glass gob that causes an increase in the resistance encountered by the parison is detected by the occurrence of a nonlinearity in the press curve; and the time at which the mold becomes completely filled with glass from the glass gob that results in a slowing in the movement of the plunger below a particular level. By ascertaining these times (each of which is measured from the initiation of the parison forming cycle), the times at which pressure changes can be determined.
The time that the pressure is changed from the first pressure to the second pressure is a first predetermined percentage of the ascertained time at which the upper part of the mold becomes filled with glass, and the time that the pressure is changed from the second pressure to the third pressure is a second predetermined percentage of the time at which the mold becomes completely filled with glass. The two characteristics from one previous parison forming cycle may be used, or more than one previous parison forming cycles may be used by averaging the ascertained times from the previous parison forming cycles. The first predetermined percentage is less than one hundred percent in order to prevent the blow mold from being forced open, and the second predetermined percentage is less than one hundred percent in order to prevent the occurrence of an overpressed finish.
In a method of implementing the dwell time control method and system of the present invention: the position of the plunger in the blank mold is monitored with respect to time during at least one parison forming cycle beginning at a time t 1 and ending at a time t 4 ; a time t 2 is determined in each monitored parison forming cycle at which a first characteristic of the movement of the plunger during the parison forming cycle is detected; a time t 3 is determined in each monitored parison forming cycle at which a second characteristic of the movement of the plunger during the parison forming cycle is detected; during each parison forming cycle, after a gob is loaded into the blank mold, applying a first pressure from time t 2 to time t p2 , a second pressure from time t p2 to time t p3 , and a third pressure from time t p3 to time t 4 ; wherein the time interval between time t 1 and time t p2 is a first predetermined percentage of a time interval based upon the time interval between time t 1 and time t 2 for one or more previous parison forming cycles; and wherein the time interval between time t 1 and time t p3 is a second predetermined percentage of a time interval based upon the time interval between time t 1 and time t 3 for one or more previous parison forming cycles.
Pursuant to this method: the first characteristic of the movement of the plunger may be a nonlinearity exhibited by the movement of the parison with respect to time which is indicative of an upper part of the mold having been filled with glass from the glass gob, and the time t 2 in each monitored parison forming cycle is the time at which an upper part of the mold has been filled with glass from the glass gob; and the second characteristic of the movement of the plunger may be a movement-related characteristic of the plunger falls below a preselected level which is indicative of the glass from the glass gob has been distributed throughout the entire blank mold to completely fill it, and the time t 3 in each monitored parison forming cycle is the time at which the glass from the glass gob has been distributed throughout the entire blank mold to completely fill it.
In a system for implementing the dwell time control method and system of the present invention: a position sensor monitors the position of the plunger in the blank mold versus time during at least one parison forming cycle beginning at a time t 1 and ending at a time t 4 ; a control system determines a time t 2 in each monitored parison forming cycle at which a first characteristic of the movement of the plunger during the parison forming cycle is detected, determines a time t 3 in each monitored parison forming cycle at which a second characteristic of the movement of the plunger during the parison forming cycle is detected, and operates the source of a pressurized medium during each parison forming cycle, after a gob is loaded into the blank mold, to apply a first pressure from time t 1 to time t p2 , a second pressure from time t p2 to time t p3 , and a third pressure from time t p3 to time t 4 ; wherein the time interval between time t 1 and time t p2 is calculated by the control system to be a first predetermined percentage of a time interval based upon the time interval between time t 1 and time t 2 for one or more previous parison forming cycles; and wherein the time interval between time t 1 and time t p3 is calculated by the control system to be a second predetermined percentage of a time interval based upon the time interval between time t 1 and time t 3 for one or more previous parison forming cycles.
It may therefore be seen that the present invention teaches an improved dwell time control method and system that results in the ability to control the dwell time (the time that the plunger is in full contact with the parison). The improved dwell time control method and system automates the pressure switching process without requiring operator input once the process has been initiated. The dwell time control method and system also prevents the inadvertent opening of molds due to the occurrence of overpressure situations.
The dwell time control method and system of the present invention is of a construction which is both durable and long lasting, and which will require little or no maintenance to be provided by the user throughout its operating lifetime. The dwell time control method and system of the present invention is also of inexpensive construction to enhance its market appeal and to thereby afford it the broadest possible market. Finally, all of the aforesaid advantages and objectives of the dwell time control method and system of the present invention are achieved without incurring any substantial relative disadvantage.
DESCRIPTION OF THE DRAWINGS
These and other advantages of the present invention are best understood with reference to the drawings, in which:
FIG. 1 is a schematic cross-sectional view of a blank mold and an associated plunger mechanism illustrating a glass gob in the blank mold with the plunger in the loading position in the blank mold; and
FIG. 2 depicts two time-aligned plots associated with the dwell time control method and system of the present invention, with the top plot showing the pressure supplied to the plunger mechanism illustrated in FIG. 1 to press it into the glass gob to form a parison, and the bottom plot showing the actual position of the plunger in the blank mold.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 , a blank mold and an associated plunger mechanism are illustrated. The mold includes two mold halves 30 and 32 , which are shown as being closed atop two neck ring halves 34 and 36 . A plunger 38 is shown extending upwardly into the bottom of the mold halves 30 and 32 , with the plunger 28 being in the loading position in the mold halves 30 and 32 . A glass gob 40 is shown loaded into the mold halves 30 and 32 , with a baffle 42 shown atop the mold halves 30 and 32 and closing the top ends thereof.
The plunger operating mechanism is housed by a lower cylinder 44 , and upper cylinder 46 on top of the lower cylinder 44 , and a cylinder cap 48 that is mounted on top of the upper cylinder 46 . A hollow sleeve 50 has a cylindrical upper portion 52 that extends upwardly through the cylinder cap 48 and into the area between the bottom portions of the neck ring halves 34 and 36 . The sleeve 50 has a central portion that includes an outwardly extending circular flange 54 , and a bottom portion 56 . A guiding ring 58 is located at the top of the upper portion 52 of the sleeve 50 , and the plunger 38 extends through the upper portion 52 of the sleeve 50 and the guiding ring 58 and into the bottom of the mold halves 30 and 32 .
The bottom of the plunger 38 is mounted onto the top of a plunger base 60 , which is slidably mounted in the interior of the sleeve 50 . The bottom of the upper cylinder 46 has a reduced diameter aperture located therein in which a piston rod 62 is slidably mounted. The piston rod 62 is connected at its top end thereof to the bottom of the plunger base 60 , and at its bottom end to the top of a piston 64 that is slidably mounted in the bottom cylinder 44 . It will be appreciated that movement of the piston 64 in the lower cylinder 44 will drive the plunger 38 .
A cooling tube 66 extends from the closed bottom of the lower cylinder 44 upwardly through the piston 64 and into the hollow interior of the piston rod 64 to provide cooling fluid thereinto. A spring 68 is mounted in the upper cylinder 46 , and extends between the top side of the bottom of the upper cylinder 46 and the bottom side of the circular flange 54 . The spring 68 functions to bias the plunger 38 to its loading position as shown in FIG. 1 by driving the circular flange 54 of the sleeve 50 into contact with the underside of the cylinder cap 48 in the absence of any downward pressure on the piston 64 in the lower cylinder 44 .
Pressurized fluid (typically compressed air) may be supplied to drive the piston 64 and the plunger upwardly through a first or lower inlet 70 , and pressurized fluid may be supplied to drive the piston 64 and the plunger 38 downwardly through a second or upper inlet 72 . It should be noted that in order to drive the plunger 38 downwardly from the loading position it is illustrated in FIG. 1 it is necessary to overcome the force of the spring 68 . This will also cause the sleeve 50 and the guiding ring 58 to be lowered from their respective positions illustrated in FIG. 1 to somewhat retract them from the neck ring halves 34 and 36 .
Pressurized fluid is supplied from a first pressure source 74 with both the flow of pressurized fluid from the first pressure source 74 and the pressure at which the pressurized fluid is supplied to the lower inlet 70 being controlled by a first proportional valve 76 . Similarly, pressurized fluid is supplied from a second pressure source 78 with both the flow of pressurized fluid from the second pressure source 78 and the pressure at which the pressurized fluid is supplied to the upper inlet 72 being controlled by a second proportional valve 80 (although a simple on/off valve will also suffice since the function is simply to drive the piston 64 to retract the plunger downwardly).
The operation of the first proportional valve 76 and the second proportional valve 80 are controlled by a control system 82 , which stores programmed information and data in a memory 84 . The operation of the control system 82 may be monitored on a display 86 , and controlled using an input control 88 . Information regarding the position of the plunger 38 is provided by a position sensor 90 that monitors the position of the piston rod 62 , the movement of which corresponds with the position of the distal end of the plunger 38 in the mold halves 30 and 32 . The position sensor 90 uses the relative positions of the piston 64 and the piston rod 62 with respect to the cooling tube 66 to provide an input regarding the position of the plunger 38 to the control system 82 .
Referring next to FIG. 2 , an exemplary use of a three-pressure operation to drive the plunger 38 (shown in FIG. 1 ) from the loading position (in which it is illustrated in FIG. 1 ) to form the parison from the glass gob in the blank mold is illustrated. According to the teachings of the present invention, the three consecutive pressures, referred to herein as p 1 , p 2 , and p 3 , are cumulatively applied during a time period beginning at time t 1 and ending at time t 4 . It will be appreciated by those skilled in the art that a single cycle of the blow molding process lasts for a predefined and unchangeable time period that is determined by the operational speed of the I.S. machine (typically one full cycle lasts for approximately four to five seconds). Similarly, the time period beginning at time t 1 and ending at time t 4 is a predefined and similarly unchangeable time period that is established by the timing of the cycle of the operations of the I.S. machine (typically this time period is approximately one second).
The dwell time control method and system of the present invention detects two events that occur during the time period that begins at time t 2 and ends at time t 4 , with the respective times at which these two events occur being time t 2 and time t 3 . The first of these events, which occurs at time t 2 , is when the plunger 38 (shown in FIG. 1 ) has forced the glass gob 40 (also shown in FIG. 1 ) to hit the baffle 42 (also shown in FIG. 1 ), at which point a non-linear increase in resistance to further movement of the plunger 38 due to the upper part of the mold having been filled with glass from the glass gob 40 .
This may be seen in FIG. 2 in the bottom plot which shows the position of the plunger 38 in the blank mold at the point identified by the intersection of the plot with the time t 2 . At the point where the upper part of the mold is completely filled with glass from the glass gob 40 , there is a readily observable nonlinear characteristic or “knee” in the plot of the position of the plunger 38 in the blank mold. This time t 2 may be detected by the dwell time control method and system of the present invention by monitoring the first and second derivatives (velocity and acceleration) of the position of the plunger 38 in the blank mold.
The second of these events, which occurs at time t 3 , is when the first and second derivatives (velocity and acceleration) of the plunger 38 have fallen below preset levels, which generally occurs when the glass from the glass gob 40 has been distributed throughout the entire blank mold, completely filling it. This may be seen in FIG. 2 in the bottom plot showing the position of the plunger 38 in the blank mold at the point identified by the intersection of the plot with the time t 3 . The time period from time t 1 to time t 3 is parison forming time and is also referred to as the “pressing time.” During the time period beginning at time t 3 and ending at time t 4 , the final pressing of the glass in the mold into a parison occurs. This time period, which is commonly referred to as the “dwell time,” is generally at least a certain time period, for example approximately between 400 and 600 milliseconds.
Thus, what can be varied by the dwell time control method and system of the present invention are the time at which the first pressure p 1 is changed to the second pressure p 2 , which time will be referred to herein as time t p2 , and the time at which the second pressure p 2 is changed to the third pressure p 3 , which time will be referred to herein as time t p3 . The present invention uses the measured times t 2 and t 3 of two detected events from the plot of the position of the plunger 38 in the blank mold during previous cycles as the triggering events to calculate the time t p2 at which the pressure applied to the plunger 38 will change from p 1 to p 2 , and the time t p3 at which the pressure applied to the plunger 38 will change from p 2 to p 3 .
The first pressure p 1 is highest since higher pressure is needed to overcome initial friction and to accelerate the movement of the plunger 38 . However, this higher first pressure p 1 must be removed before the glass in the glass gob 40 hits the baffle 42 in order to prevent the blow mold from being forced open. In order to ensure that this does not happen, the time interval between time t 1 and time t p2 after which the pressure applied to the plunger 38 will change from p 1 to p 2 is selected to be a percentage of the measured time interval between time t 1 and time t 2 for one or more previous I.S. machine cycles (if this time interval is measured for more than one machine cycle, the measured times may be averaged).
In a preferred embodiment, the time interval between time t 1 and time t p2 can vary from approximately sixty percent to approximately ninety-five percent of the time interval between time t 1 and time t 2 . In a more preferred embodiment, the time interval between time t 1 and time t p2 can vary from approximately seventy percent to approximately ninety percent of the time interval between time t 1 and time t 2 . In a most preferred embodiment, the time interval between time t 1 and time t p2 is approximately eighty percent of the time interval between time t 1 and time t 2 .
The number of prior cycles over which the time interval between time t 1 and time t 2 can be measured and averaged may be varied from one cycle (in which case no averaging is needed) to one hundred cycles or even more in preferred embodiments, with consideration being given to a balancing of only recent cycles being used and a greater number of cycles being used. In a more preferred embodiment, this balancing uses a number of cycles that is between approximately three cycles and approximately twenty cycles to calculate the average, and in a most preferred embodiment, this balancing uses approximately eight cycles to calculate the average. In each case, the measurements of the time interval between time t 1 and time t 2 are used for the given number of immediately preceding cycles, so that a new average value is calculated for each succeeding cycle.
The third pressure p 3 may be lower than the second pressure p 2 in order to have a higher pressure p 2 to complete the pressing time of the glass gob 40 in the blank mold quickly and to have a lower pressure p 3 in order to prevent the occurrence of an overpressed finish. In this case, this higher second pressure p 2 should be removed before the glass in the glass gob 40 fills the blank mold in order to prevent the finish from being overpressed. In order to ensure that this does not happen, the time interval between time t 1 and time t p , after which the pressure applied to the plunger 38 will change from p 2 to a lower p 3 is selected to be a percentage of the measured time interval between time t 1 and time t 3 (alternately, it could instead be a percentage of the measured time interval between time t p2 and time t 3 , or even a percentage of the measured time interval between time t 2 and time t 3 , although these alternatives are not the most preferred implementation of the dwell time control method and system of the present invention).
In a preferred embodiment, the time interval between time t 1 and time t p3 can vary from approximately fifty percent to approximately ninety percent of the time interval between time t 1 and time t 3 . In a more preferred embodiment, the time interval between time t 1 and time t p3 can vary from approximately sixty percent to approximately eighty percent of the time interval between time t 1 and time t 3 . In a most preferred embodiment, the time interval between time t 1 and time t p3 is approximately seventy percent of the time interval between t 1 and t 3 .
The number of prior cycles over which the time interval between time t 1 and time t 3 can be measured and averaged may be varied from one cycle (in which case no averaging is needed) to one hundred cycles or even more in preferred embodiments, with consideration being given to a balancing of only recent cycles being used and a greater number of cycles being used. In a more preferred embodiment, this balancing uses a number of cycles that is between approximately three cycles and approximately twenty cycles to calculate the average, and in a most preferred embodiment, this balancing uses approximately eight cycles to calculate the average. In each case, the measurements of the time interval between time t 1 and time t 3 are used for the given number of immediately preceding cycles, so that a new average value is calculated for each succeeding cycle.
If the first alternate embodiment mentioned above is used instead, the time interval between time t p2 and time t p3 can vary from approximately forty-five percent to approximately eighty-five percent of the time interval between time t p2 and time t 3 . In a more preferred embodiment, the time interval between time t p2 and time t p3 can vary from approximately fifty-five percent to approximately seventy-five percent of the time interval between time t p2 and time t 3 . In a most preferred embodiment, the time interval between time t p2 and time t p3 is approximately sixty-five percent of the time interval between time t p2 and time t 3 .
In some instances (such as, for example, producing wide mouth glass containers) it may be desirable to have p 3 be greater than p 2 (and also to have p 2 be greater than p 1 ). This may be done because during the dwell time the plunger 38 is in contact with the parison in the glass gob 40 in the blank mold, and as such is either not moving or moving at such an exceedingly low rate that it has essentially no momentum. As such, it may be possible for the dwell time pressure to be higher than the second pressure p 2 used during the pressing time, although this alternatives is generally not the most preferred implementation of the dwell time control method and system of the present invention (except perhaps in the production of wide mouth glass containers).
Since the time period that begins at time t 1 and ends at time t 4 is fixed, and since it is desirable to have a dwell time beginning at time t 3 and ending at time t 4 that is at least a minimum time period long, such as, for example, between approximately 400 and 600 milliseconds long, it is possible in an alternate embodiment to have the objective of defining a desired value for the time t 3 . By varying the values of either the second pressure p 2 only, or by varying the values of both the first pressure p 1 and the second pressure p 2 with them in a fixed relationship (e.g., the first pressure p 1 is equal to 1.12 times the second pressure p 2 ), this objective for a dwell time beginning at a desired value for the time t 3 can be realized in relatively few parison forming cycles.
Depending upon the specific mold design, various loading possibilities, and the variations possible in other parameters, virtually every possible combination of p 1 , p 2 , p 3 levels could, in some instances, make sense. All possible combinations are thus viewed as being encompassed by the improved dwell time control method and system.
It may therefore be appreciated from the above detailed description of the preferred embodiment of the present invention that it teaches an improved dwell time control method and system that results in the ability to control the dwell time (the time that the plunger is in full contact with the parison in the gob). The improved dwell time control method and system automates the pressure switching process without requiring operator input once the process has been initiated. The dwell time control method and system also prevents the inadvertent opening of molds due to the occurrence of overpressure situations.
The dwell time control method and system of the present invention is of a construction which is both durable and long lasting, and which will require little or no maintenance to be provided by the user throughout its operating lifetime. The dwell time control method and system of the present invention is also of inexpensive construction to enhance its market appeal and to thereby afford it the broadest possible market. Finally, all of the aforesaid advantages and objectives of the dwell time control method and system of the present invention are achieved without incurring any substantial relative disadvantage.
Although the foregoing description of the dwell time control method and system of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were 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 changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
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A dwell time control system and method for automatically adjusting the selection and timing of a sequence of pressures used to drive the plunger in a parison mold during the parison forming process. The timing of characteristics of the observed press curve from one or more previous parison forming cycles are ascertained and used to control the timing of the changes in pressure during a subsequent parison forming cycle. The timings of these changes of pressure are determined as predetermined percentages of the timings of the characteristics in order to prevent the blow mold from being forced open and in order to prevent the occurrence of an overpressed finish.
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CROSS REFERENCE TO RELATED APPLICATION
This application is a division of my co-pending application Ser. No. 964,739, filed Nov. 29, 1978, now U.S. Pat. No. 4,244,726, which in turn is a continuation-in-part of my application Ser. No. 906,048, filed May 15, 1978, now abandoned.
BACKGROUND OF THE INVENTION
In the glass industry today the most common glass container manufacturing machine is the Hartford type "I.S." machine. It is estimated that in the United States alone, there are over six thousand "I.S." sections in daily operation. This machine is described in Ingle U.S. Pat. Nos. 1,843,160 and 1,911,119.
A basic "I.S." eight-section machine today costs several hundred thousand dollars. An important advantage of the present invention is that it is applicable to the existing production facilities of the industry.
In the original disclosure of the I.S. machine, the machine was intended to make glass containers by the well-known "blow and blow" process. Subsequently, Rowe U.S. Pat. No. 2,289,046 disclosed the "62" process which could be applied to the basic machine to enable it to make containers by the "press and blow" process which is the preferred method of manufacturing wide mouth ware or jars. This development enabled the glass industry to use one machine for all types of ware instead of having a "narrow neck" machine like the Owens or Lynch machines for making bottles and a "widemouth" machine like the Miller machine for making jars.
The present invention relates primarily to the manufacture of glass containers on the I.S. machine by the well-known "blow and blow" process although there are some instances where it can also be used to advantage in the manufacture of glass containers in the I.S. machine using the "press and blow" process. Although minor variations to the process exist in the industry, the following discussion describes generally the steps which are most common. A gob of molten glass is delivered into an inverted blank mold at the bottom of which is situated a neck ring and a plunger. The gob is blown down into the cavity with compressed air to insure the complete filling of the neck ring. The plunger is then receded, a baffle plate closes the top end of the blank cavity, and compressed air is applied through the orifice created by the withdrawal of the plunger, thereby expanding the glass into intimate contact with the interior surfaces of the blank mold and baffle plate. The glass-to-mold contact is continued long enough to create an "enamel" skin on the outer surface of the resulting glass parison.
The baffle plate is then removed and the blank mold is slightly disengaged from the parison so that the parison is held in a vertical position supported only by the neck ring. At this time, the parison starts to "reheat" which refers to the flow of heat from the interior glass to the outer surfaces of the parison and to the heat reflected from the interior surface of the blank mold to the outer surface of the parison. The step of reheating the parison plays an important role in improving the strength of the final glass bottle. Following this, the neck ring and parison are transferred and inverted to the blow mold position. The blow mold closes around the parison as the neck ring releases its hold, and the parison becomes supported at the top of the blow mold by a finish ring or bead located just below the finish of the parison. The parison, of course, continues to reheat during its transfer to and positioning in the blow mold until the time it is expanded into contact with the interior wall of the blow mold.
After its suspension in the blow mold, compressed air and/or vacuum are applied, at the proper time, to expand the parison to the interior contours of the blow mold. The cooling contact between the blown glass bottle and the blow mold is maintained until the bottle assumes a sufficient degree of rigidity to be capable of standing on its own. Then the blow mold is opened and the glass bottle is removed therefrom and transferred to a cooling plate or conveyor.
As glass bottles have been designed for lighter weights and thinner walls, the length of time required to blow and cool the bottle in the blow mold has decreased significantly. Therefore, in order to maintain the blank side time in the proper relation to the blow side time, it has been necessary to reduce the time available for reheating the parison.
In the ideal production of thin-walled containers, the interval for reheating prior to blowing must exceed a predetermined minimum period of time in order to insure equalization of temperatures in all zones of the parison and to thus achieve uniform viscosity prior to final expansion. Reheating of the parison walls proceeds from the interior zone toward the exterior and, therefore, this step cannot be speeded up appreciably by auxiliary equipment. It also requires more time on containers where the parison has been formed by the "blow and blow" process than as those where the parison has been formed by the "press and blow" process because, in the former there is no plunger contact to cool the interior wall of the parison as there is in the latter process.
Many inventors, recognizing the importance of the "reheat" have proposed means to increase it. These include Wadman U.S. Pat. No. 2,084,285, Wadman U.S. Pat. No. 2,151,876, Becker U.S. Pat. No. 3,622,304, Foster U.S. Pat. No. 4,009,016 and Zappia U.S. Pat. No. 4,058,388. Because none of these disclosures is applicable to the basic "I.S." machine they have not met with commercial acceptance.
It is important to keep the proper relationship between the blank side time and the blow side time to maintain a proper amount of reheating for the parison. In an attempt to improve the reheating time for the parisons additional blow molds have been provided so that the parisons can have additional reheat time without slowing down the parison forming or bottle forming process. The additional blow molds have been added to the bottle forming machine in usually one of two ways in the prior art. An additional set of blow molds can be added to one side of the parison forming equipment so that the parisons can alternately be supplied to each set of horizontally separated blow molds. (U.S. Pat. No. 3,216,813 is one example of this type of prior art system). The additional blow molds add a great deal of width to the bottle forming machine and require an additional parison transfer mechanism to service the additional blow molds. Such a mechanism requires a complete revamping of the forming stations and cannot be used with the standard I.S. machine.
The other prior art solution is to place two sets of blow molds on a horizontally reciprocating mechanism that alternately moves a blow mold set into position to receive parisons (U.S. Pat. No. 2,151,876 is one example of this type of prior art system). Once the first set of blow molds receives parisons the molds are horizontally translated and the second set of blow molds moves into position to receive parisons. The arrangement allows the parisons to have adequate reheat time while the parisons are being transferred to the blow molds and before the parisons are blown or expanded in the blow molds. However, the horizontal movement of the blow molds can cause the parisons to deform or move in the blow molds. Any such movement of the molten glass can produce non-uniformities in the parison that create non-uniformities in the finished blown bottle. Also the parison can deform to an extent, during the horizontal movement, to cause the parisons to contact the surface of the blow molds. Once the parisons contact the surface of the molds heat transfer occurs between the portion of the parison and the mold. The transfer disrupts the reheating of the parison in the area where the parison is in contact with the mold and creates a non-uniform reheating of the parison. The non-uniform reheating of the parison can create weak spots or defects in the finished bottle. The transfer of the parisons from the parison forming molds to the blow molds can also cause the parisons to deform or become off center. The subsequent horizontal movement of the blow molds will tend to magnify any such defects in the parisons and result in unsatisfactory bottles. Accordingly, the prior art solutions to the reheat problems have proven to be inadequate and not adaptable to present machines.
A substantial advantage of the present invention is that it is designed to be used with the Hartford type I.S. bottle forming machines. The Hartford type I.S. machine forming section has a width of under two (2) feet and bottle production facilities are designed to take maximum advantage of this width. The vertically reciprocating blow molds of the present invention can be added to the Hartford type I.S. machine without increasing the width of the bottle forming station of the machine. Thus, the present invention can be used to increase production rate in a bottle forming facility by adding the invention to standard bottle forming machinery.
SUMMARY OF THE INVENTION
The present invention relates to and provides a novel modification to the known bottle forming process whereby reheat time is maintained for thinner and lighter bottles, and production speed is increased. The reheat time itself is maintained or increased by eliminating some or all of the reheat part of the cycle from the blank mold section and placing it in the blow mold section. Sufficient time for reheating and blowing at higher production rates is made available by using a plurality of blow molds for each blank mold. With this arrangement, one set of parisons may be reheated and blown in one set of blow molds while, at a second set of blow molds, blowing of a set of bottles is completed, the bottles are removed and a new set of parisons is delivered. The plurality of blow molds reciprocate along a substantially vertical path and into and out of a position where the parisons are alternately received by the pairs of blow molds. The vertical path falls within the plane of transfer of the parison from the blank mold to the blow molds. The parisons are held in the blow molds for a sufficient period of time to achieve reheating prior to blowing the parisons into bottles. Reheating the parisons in the blow molds can improve the glass distribution because of the gravitational centering of the parisons with respect to the blow molds. This may be necessary if the parisons have been forced off-center by the action of the parison transferring mechanism.
Although the invention is described as having two sets of blow molds it should be noted a greater number of sets of blow molds could be used in this invention. The additional blow mold sets would be positioned so that they reciprocate along the vertical path with the other blow mold sets. In this fashion any number of blow molds could be utilized to obtain the desired amount of reheat time. However, for the sake of explanation, the invention will be described as having two sets of blow molds.
It is therefore, an object of the invention to provide a method of manufacturing lightweight glass bottles whereby a substantially increased reheat time is available for promoting the strength of the bottle.
It is further an object of this invention to provide a method of manufacturing lightweight glass bottles whereby the production speed and efficiency is increased.
It is still further an object of the present invention to provide a method of manufacturing glass bottles whereby the uniformity of glass distribution is improved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1-5 are overall schematic views of a portion of a glass bottle manufacturing machine illustrating the steps of a preferred method of the present invention; and
FIG. 1a is a front and partial sectional view of the reciprocating blow mold apparatus in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is an improvement in the method of manufacturing narrow neck glass bottles by the well-known "blow and blow" process. However, it will be apparent to the artisan that the method may also be used with the "press and blow" process with some utility. For detailed descriptions of typical apparatus and procedures used in the "blow and blow" process, reference may be had to the following U.S. Pat. Nos.: 1,911,119; 2,289,046; 2,290,798; 2,309,378; 2,355,036 and 2,702,444. Of course, most of the machinery used with other methods, such as "press and blow" are also useful with the present invention and references may be had to such machinery as typically shown in U.S. Pat. Nos. 2,289,046 and 3,024,571. For purposes of understanding the present invention, reference will be made to the simplified illustrations in FIGS. 1-5, and 1a.
FIGS. 1-5 depict only that portions of the glass container manufacturing apparatus which is most directly concerned with the method of the present invention, i.e., a parison-forming unit 10, a transfer mechanism 11, and a reciprocating blow mold apparatus 12. FIG. 1a is a front view of the blow mold apparatus 12 as shown in FIG. 1. The apparatus is intended to replace the standard comparable forming station of existing I.S. machines.
For purposes of illustration, FIG. 1 portrays the point during manufacture at which the parisons 15 have already been formed and are ready for transfer. The actual method and the I.S. machines used for forming the parison 15 in the blow and blow process are well-known in the art and do not constitute a critical part of the present invention. Generally, such parisons 15 are formed by delivering glass charges or gobs to an inverted split blank mold 16 having multiple cavities 16a, and which comprises two mold halves pivotally movable into and out of a parison forming position about a stationary pivot pin 17. The blank mold 16 lies superjacent to a split neck ring 18 supported by a neck ring holder 19, both of which are detachably affixed to a support arm 20 for invert transferring the formed parisons 15 to the blow mold apparatus 12. Immediately below the neck ring 18, and in alignment therewith, is mounted a vertically disposed, generally cylindrical housing 25 which contains the operating mechanism for counter-blowing the glass charges into a pair of parisons 15. In operation, after the glass charges have been delivered to the blank mold 16, the mold 16 is closed at the top with baffles (not shown), and settle blown, by means of compressed air directed into the mold 16 through the baffles, to assure complete molding of the finish threads in the neck ring 18 and to compact the charge. During the time the parisons are settle blown, a neck pin or plunger (not shown) is situated within each neck ring 18, but is subsequently retracted to form a small cavity within the compacted glass charge. Compressed air is counter-blown into the cavity to expand the charge against the molding surfaces of the blank mold 16 and baffles to form the parisons 15. After formation of the parisons 15, the baffles are removed and the parisons are ready to be transferred to the blow mold apparatus, as shown in FIG. 1. Additional information on the formation of the parisons can be found in U.S. Pat. No. 2,151,876 and the patents cited therein.
The two halves of the blank mold 16 are then pivoted open and the support arm 20 invert transfers the formed parisons 15, neck ring 18, and neck ring holder 19, to the blow mold apparatus 12, as depicted in FIG. 2. A known transfer mechanism 11 which is suitable for use with the present invention is disclosed in U.S. Pat. No. 3,024,571. Basically, it comprises a pinion 30 and an engaging vertically disposed pinion rack 31, both mounted upon a stationary base or section box 32, and operated by means of a piston and cylinder assembly 33. Compressed air through one inlet 34 of the cylinder 35, pushes the piston 36 and piston rod 37 upward, thereby driving the engaged pinion 30 about its fulcrum shaft 38 and invert transferring the support arm 20 and parisons 15 to the blow mold apparatus 12. In order to return the support arm 20 to the blank side, the air in the cylinder 35 is bled, and additional air is fed through the inlet 34a to the reverse side 46 of the cylinder 35.
In the present invention, the formed parisons 15 are delivered alternately to one of two blow mold stations, 50 and 51, of the blow mold apparatus 12. In FIG. 2 the parisons 15 are being delivered to the upper blow mold station 50.
The mold stations, 50 and 51, include, in the form shown, in FIGS. 1 and 1a, two multiple cavity cooperating mold sections 52 and 52a detachably supported respectively by mold holder arms 53 and 53a, and which are openable and closeable translationly by means of respective piston/cylinder assemblies 54 and 54a. Each of the piston/cylinder assemblies 54 and 54a includes two cylinder mechanisms 55, 55a, 56 and 56a, each of which operate one of the two cooperating mold sections 52 and 52a. For purposes of illustration, one of each of the mechanisms at each blow mold station, 50 and 51, is shown in sectional view in FIG. 1a.
Each cylinder mechanism, 55, 55a 56 and 56a, includes a respective cylinder 60, a piston 61, a piston rod 62, and two air inlets 63 and 63a for the upper cylinder assembly 55, and 63b and 63c for the lower cylinder assembly 55a. The piston rods 62 are connected to the respective mold holder arms 53 and 53a. In each of these sections compressed air is introduced, through the inlet 63 or 63a, into the cylinder 60 and pushes the piston 61 and piston rod 62 outward, thereby opening the mold sections 52, as illustrated by the upper blow mold station 50 in FIG. 1a. When compressed air is applied through the other inlet 63a or 63b, and the air on the opposite side of the piston 61a is allowed to evacuate, the piston rod 62 or 62a is forced back into the associated cylinder 60a, thereby closing the mold sections 52 or 52a, as shown by the lower blow mold station 51 in FIG. 1a. Movement of the piston rods causes the mold holders arms 53 and 53a to move to open and close the mold sections. The mold holder arms and mold sections are caused to move along a plane that is perpendicular to the longitudinal axis of the bottles formed in the mold sections. Thus, the mold sections move translationly away from and towards one another during the opening and closing of the mold sections. This expedient, combined with the vacuum force holding the mold closed, greatly reduces the complexity of the mold operating mechanism.
Each of the pair of stations, 50 and 51, is supported upon a respective plate 64, 64a which is affixed to a laterally spaced sliding bars 65 and 65a, and finally aligned to the stationary base 32 by means of a bracket 66 and 66a. Bearings 67 affixed to the brackets assure horizontal alignment. The sliding bars 65 and 65a, and thus the stations 50 and 51, are reciprocated up and down by means of a piston/cylinder assembly 70, for a purpose to be explained below. The piston/cylinder assembly 70 includes a cylinder 71, piston 72, piston rod 73, air inlets 74 and 74a, and a drive plate member 75. Compressed air admitted into the cylinder 71 through the air inlet 74 pushes the piston 72 and rod 73 upward, thereby resulting in the drive member 75 raising the stations, 50 and 51. Compressed air admitted to the other side of the piston 72 through the air inlet 74a pushes the piston 72 downward, thereby lowering the blow mold stations, 50 and 51.
The timing of opening and closing the blow mold section 52 is controlled to coincide with the removal of the finished bottles 80 and delivery of the formed parisons 15, as shown in FIGS. 1 and 2. Removal of the finished bottles 80 is accomplished by means of a conventional takeout jaw assembly 81. The takeout jaw assembly 81 includes pairs of takeout jaws 82 supported by a takeout arm 83 which is pivotally mounted on a bracket 84 (FIG. 2). Thus, finished bottles 80 are removed from the blow mold sections 51 and 52 and delivered to a dead-plate 85 where they are subsequently transferred to a hot end treatment station (not shown) and an annealing lehr (not shown).
Expansion of the parisons 15 is preferably performed by applying a vaccum through slits or apertures (not shown) within the mold sections 51 and 52. The vacuum lines may comprise flexible hoses 90 connected to the hollow interior of each of the sliding bars 65. The vacuum within the sliding bars is utilized to expand the parisons 15 in a known manner. The valve controlling the vacuum to the mold is located as close to the mold as possible as is known in the art. Vacuum expansion is preferred in order to promote uniformity in glass distribution and to assist in holding the mold sections 52 together. However, blow expansion would also be suitable. Additional information on expanding the parisons into bottles can be found in U.S. Pat. No. 1,911,119.
After the finished bottles 80 are removed from the mold sections 52 of the upper blow mold station 50 and the formed parisons 15 are delivered thereto, the piston/cylinder assembly 33 of the transfer mechanism 11 is actuated to return the neck rings 18 to the parison-forming unit 10. The piston/cylinder assembly 70 is then actuated to raise the stations, 50 and 51. This is shown in FIG. 3. When the lower blow mold station 51 reaches the takeout position, the blow mold sections 52 are opened by action of the piston/cylinder assembly 54, the finished bottles 80 are removed by the take-out mechanism 81 and the new parisons 15 are positioned in the mold sections 52, as shown in FIG. 5. The mold sections 52 are immediately closed by the action of the piston/cylinder assembly 54 and then the piston/cylinder assembly 70 is actuated to lower the blow mold stations, 50 and 51, to the position shown in FIG. 1 and the process is repeated. Thus, one parison forming unit 10 is used to supply parisons to two mold stations. The mold stations are reciprocated in a substantially vertical plane to a takeout position where the finished bottles are removed and another set of parisons supplied to the mold station. The mold stations are then reciprocated until the other mold station is in the takeout position and the process is repeated for that mold station.
The expansion of the parisons 15 in the upper mold station 50 can start at any time after delivery of the parisons, even while the station 50 is in motion. The reheating of the parisons continues to take place during the transfer from the parison forming unit and while the parisons are in the mold stations prior to blowing. Reheating will occur in the mold stations as long as the parisons are not in contact with the walls of the mold. A portion of the reheat time in the mold stations will occur when the mold stations are in motion. However, since the mold stations move in a vertical direction the parisons are not caused to deform or shift off center in the mold stations. In fact, the reheating in the mold stations will serve to redistribute any hot glass in the parison that has shifted off center due to the forces generated in transferring the parison forming unit to the mold stations.
The amount of reheating time available is dependent on the length of time between the point at which the parisons are removed from the contact with the blank mold and the point at which the parisons are fully expanded in the mold. By utilizing two blow mold stations the parisons can remain in the molds for a longer period of time for reheating without causing the bottle production operation to slow down. The reciprocating cycle of the mold stations, the opening and closing of the molds, the blowing of the parison into a bottle and the reheat time alotted in a particular bottle can all be controlled to achieve the best possible results.
A timing drum 95 is usually used to control the transfer of the parison, the reciprocation of the mold stations, the opening and closing of the molds, the blowing of the parisons into bottles and the removal of the bottles from the mold stations. An example of suitable timing drum arrangement is shown in U.S. Pat. Nos. 2,084,285 and 2,151,876 although it should be noted that almost any mechanical or electrical control device can be used to control the bottle forming process. The timing drum or other control device used are standard components in this industry and as such are not part of applicant's invention. The control of the above functions by the timing drum provides considerable flexibility in selecting the amount of reheat time and consequently blow time, for the bottles that are manufactured. This flexibility is necessary to allow the machines to manufacture bottles of different designs at maximum production speed for each design.
For example the timing drum 95 may be set up to offset the different effects of gravity on the parisons within the two sets of blow molds. When the sets of blow molds 50 moves up from the receiving station the parisons therein will tend to elongate while in the set of blow molds 51 that move down from the receiving station the parisons will tend to be compressed.
It should be apparent that, while a preferred embodiment of the present invention has been described above in detail, other embodiments or modifications thereto will be obvious to persons skilled in the art without departing from the scope of the invention as defined in the following claims.
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A method for manufacturing glass bottles is disclosed which includes consecutively delivering gobs of molten glass into a blank mold, forming each gob into a parison, transferring the parisons alternately into at least two sets of blow molds, allowing said parisons to reheat, and expanding the parisons in the blow molds. The sets of blow molds reciprocate along a substantially vertical path. A first position where the parisons are alternately received by the blow molds and blown containers removed is located on the vertical path. The parisons are expanded and cooled in the blow molds by blowing them out or by applying a vacuum, or a combination of those means at a second position on the vertical path.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a United States National Phase filing of International Application No. PCT/US2009/045314 filed on May 27, 2009 which claims the benefit of U.S. Provisional Application No. 61/056,321 filed May 27, 2008, both of which are is herein incorporated by reference.
RELATED FIELD
The present devices relate generally to improving fixation of acetabular cups, and more particularly to preventing bio matter (such as soft tissue and fatty deposits) from contacting an acetabular shell during delivery through a wound until just prior to impaction.
BACKGROUND
In surgery, it is possible to contaminate an acetabular shell with bio matter, soft tissue, and fatty deposits prior to and during impaction. Each time an acetabular cup is inserted into a body cavity, soft tissues and bio matter can build up on portions of the acetabular cup and become stuck. If these materials gather onto or bind to a porous outer coating of the cup, it could adversely affect bone in-growth and initial “bite” and “fixation”. If these materials gather on a smooth inner surface of the cup, it could adversely affect subsequent taper-locking between the cup and a liner. Connections between acetabular cups and liners are generally designed with tight tolerances to form a tight fit. Bio-matter can compromise such a tight fit. The devices aim to provide a novel and unique apparatus and method of preserving the porosity of an acetabular cup during insertion into a body cavity.
US 2007/100464 AA titled “Orthopaedic implant sleeve and method” and assigned to Zimmer discloses a debris-preventing device for use with modular-style necks and femoral stems. This is shown in FIG. 1 . This reference does not disclose use with acetabular cups, and the sheaths shown in this reference teach away from providing a means for acetabular cup penetration as the disclosure is used to protect surfaces proximal to the wound.
Other related art teaches soft tissue protection devices which may be placed over a wound or within a wound. These devices are placed onto or into the wound prior to advancement of a medical device. Such a device only protects the soft tissue covered by the device from damage.
SUMMARY
The aforementioned needs are satisfied by several aspects of the devices.
According to one aspect, there is provided a method of providing a debris-preventing sheath for an acetabular cup. The method includes the steps of: creating a cup-shaped sheath for an acetabular cup which is preferably disposable and somewhat flexible, said sheath having at one end, a means for insertion of the acetabular cup. The means for insertion of the acetabular cup may comprise an open end. At another end opposite said one end, the cup is provided with a means for passage of the acetabular cup. The means for passage may be for instance, a slit, slot, hole, aperture, flap, accordion sleeve, a reduction in diameter, a perforation, a series of perforations, a perforation pattern, a perforation shape, a perforation window, and/or combinations thereof. The means for passage may comprise any shape such as a star, circle, square, pizza slice, etc.
According to another aspect, there is provided a method of using a cup-shaped sheath with an acetabular cup. The method includes the steps of: providing a cup-shaped sheath for an acetabular cup; positioning the cup within the cup-shaped sheath; inserting both of the acetabular cup and cup-shaped sheath into a body cavity; allowing the sheath to shield the acetabular cup from bio-matter (e.g., fatty and soft tissues); allowing the acetabular cup to protrude from or penetrate through said cup-shaped sheath and become affixed to a body portion (e.g., acetabulum); removing the cup-shaped sheath from the acetabular cup and from the body cavity; and, disposing of said cup-shaped sheath. The debris-preventing sheath acts as a shield for a scratchy porous acetabular shell during insertion into a body cavity. Therefore, no biomatter becomes lodged in the porous structure and porosity of the acetabular cup is retained.
Another aspect of the invention provides an acetabular cup and sheath assembly comprising a sheath and an acetabular cup. The sheath is configured to receive the acetabular cup within the sheath. The sheath and acetabular cup together are configured to pass through a surgical wound toward an implantation site. The sheath further comprises a penetration structure for passing the acetabular cup through the sheath when the acetabular cup is proximately close to an implantation site.
According to yet another aspect, there is provided a sterile-packaged implant assembly. The packaged implant assembly comprises: a cup-shaped sheath for an acetabular cup, and an acetabular cup disposed within said cup-shaped sheath; wherein the cup-shaped sheath is provided with a means for passing an acetabular cup through itself; wherein, in use, the cup-shaped sheath allows an acetabular cup to protrude or penetrate through said cup-shaped sheath and become affixed to a body portion; and wherein said cup-shaped sheath prevents build-up and/or generation of debris onto portions of the acetabular cup when the acetabular cup is placed inside a body cavity.
Another aspect of the invention provides a method of implanting an acetabular cup. The method includes forming a sheath for an acetabular cup having at one end, a penetration structure for passage of the acetabular cup through the sheath. A step receives the acetabular cup in the sheath through an end opposite the end having the penetration structure. Another step guides the sheath and the cup through a surgical wound such that the sheath is in front of the cup. Another step removes the sheath from the cup when the cup is proximately near the implantation site.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating certain embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the written description serve to explain the principles, characteristics, and features of the invention. In the drawings:
FIGS. 1 a - 1 c illustrate prior art sheaths for use with femoral stems and modular-style necks;
FIG. 1 d illustrates the problems associated with the prior art methods;
FIG. 2 illustrates one embodiment;
FIG. 3 illustrates another embodiment;
FIG. 4 illustrates yet another embodiment;
FIG. 5 illustrates yet even another embodiment;
FIG. 6 illustrates another embodiment;
FIG. 7 illustrates yet another embodiment;
FIG. 8 illustrates yet even another embodiment;
FIG. 9 illustrates another embodiment;
FIG. 10 illustrates yet another embodiment;
FIGS. 11 a - 11 c illustrate a method of packaging an embodiment; and
FIGS. 12 a - 12 e illustrate a method of using an embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
The device provides, in part, an improved method of inserting an acetabular cup (i.e., shell) into a body cavity. The method utilizes a sheath that temporarily encloses the acetabular cup during insertion into a body cavity. The sheath protects the cup from bio-matter which could compromise a good taper lock with a liner, or a good initial scratch-fit with bone.
It is preferred that the sheath be sterile-packed with the acetabular cup. The sheath may be incorporated as an integral or separate part of the acetabular cup packaging, or may have a separate part number and used as a disposable instrument. Furthermore, the sheath may be provided as a non-disposable instrument which is configured for multiple sterilizations. The sheath should be somewhat flexible at portions to allow an acetabular cup to penetrate or protrude from one end; however, the sheath may also incorporate more rigid portions at other areas for strength, conformity, and to better push surrounding soft tissues radially-outward away from the acetabular cup. Sheaths may be made so as to be capable of universal use across a variety of differently-sized acetabular cups.
The usefulness of the sheath and methods associated therewith is not limited to acetabular cups. The present device may also be advantageously used with acetabular liners, cages, and/or augments alike such that a surface away from the wound must be passed through the sheath.
FIGS. 1 a - 1 c illustrate sheaths used in the prior art for hip applications. The sheath is disposed on a proximal end of an implant and is used to protect a taper lock. The sheath is not penetrable by the implant, and is meant to roll off the implant. The embodiments of the present invention, however, include a port through which the implant must pass in order to properly position the implant in the bone.
FIG. 1 d illustrates the problems associated with prior art methods. Conventionally, acetabular cups 10 are inserted using a positioner/impactor 12 into a body cavity wound 20 without any protective sheath. The cup 10 is passed through the wound 20 across fatty tissue and soft tissue 22 until the cup 10 is positioned over the prepared acetabulum 24 . As the cup 10 is passed, the fatty tissue and soft tissue 22 may brush against the porous surface of the implant. Consequently, fatty tissues and soft tissues 30 cling to the rough, porous, or frictional surfaces of the acetabular cup 10 , which are purposely designed for bony ingrowth and initial fixation. With portions or all of the rough, porous, or frictional surfaces “gummed up” by bio-matter, bone ingrowth and the initial fixation “bite” of the acetabular cup 10 is compromised.
FIG. 2 illustrates one embodiment of a cup-shaped sheath 30 for an acetabular cup 10 . The sheath incorporates a means for acetabular cup penetration comprising a single slot 32 . The slot 32 is sized such that the cup 10 is retained within the sheath 30 as the shell 10 and sheath 30 are passed through the wound. Once the cup 10 reaches the implant site, then the cup 10 may be pushed through the slot 32 by deformation or tearing of the slot 32 and sheath 30 .
FIG. 3 illustrates another embodiment of a cup-shaped sheath 40 for an acetabular cup 10 . The sheath incorporates a means for acetabular cup penetration comprising two generally orthogonal slots 42 . While the slots are generally orthogonal, the slots may otherwise by oriented relative to each other such that the give an appropriate amount of clearance to the cup 10 as it passes through the sheath 40 . By using multiple slots crossing each other, it may be possible to have thinner or shorter slots than a single slot orientation.
FIG. 4 illustrates another embodiment of a cup-shaped sheath 50 for an acetabular cup 10 . The sheath incorporates a means for acetabular cup penetration comprising at least one aperture 52 . While the aperture 52 is generally oval, other aperture shapes for passing the shell through the sheath may be used such as a round, square or triangular apertures. The size of the aperture should be smaller than the shell but large enough so that the cup may pass through the aperture. Smaller aperture sizes may minimize the contact between the cup and the soft tissue and thus minimize the amount of bio-matter on the porous surface.
FIG. 5 illustrates another embodiment of a cup-shaped sheath 60 for an acetabular cup 10 . The sheath 60 incorporates a means for acetabular cup penetration comprising several circumferentially-spaced, radially-extending slits 62 . The slits may be simple cuts through the sheath 60 . Such a sheath 60 may preferably be made of a less flexible material so that the triangular wedges made between the slits may retain the shape of the bottom of the sheath 60 and may better retain the cup 10 from passing through the sheath 60 prematurely.
FIG. 6 illustrates another embodiment of a cup-shaped sheath 70 for an acetabular cup 10 . The sheath 70 incorporates a means for acetabular cup penetration comprising a reduced diameter end 72 . The end 72 may be extruded, but again the size of the opening should be less than the size of the cup 10 so that the cup 10 cannot pass through the sheath 70 without some amount of force between the sheath 70 and the cup 10 .
FIG. 7 illustrates another embodiment of a cup-shaped sheath 80 for an acetabular cup 10 . The sheath 80 incorporates a means for acetabular cup penetration comprising at least one flap 82 . The flap may have a reduced width connection portion to facilitate movement and passage of the acetabular cup 10 . The flap 82 may be preformed with the sheath using perforations that can be severed after the acetabular cup has passed through the body cavity and is ready for bony contact. The tab 82 may also be cut through the bottom of the sheath 80 and made from a less flexible material such as the sheath 60 of FIG. 5 .
FIG. 8 illustrates another embodiment of a cup-shaped sheath 90 for an acetabular cup 10 having a slot 92 for passing the cup 10 . The sheath incorporates at least one removal structure 94 of the sheath 90 from a body cavity. The removal structure 94 may comprise a tab, a hole, an engagement lip, or any other structure which can be engaged to easily remove the sheath 90 from a body cavity. The removal structure 94 may be engaged by the surgeon's fingers, or may be part of a mechanism attached to the impactor which would pull the sheath 90 away from the porous surface of the cup 10 .
FIG. 9 illustrates another embodiment of a cup-shaped sheath 100 for an acetabular cup 10 . The sheath 100 incorporates a means for acetabular cup penetration comprising a perforation pattern 102 . The pattern may be in a pizza-slice configuration as shown, in a simple line configuration, or in a flap configuration as shown in FIG. 7 . The perforations 102 may allow better isolation of the porous surface from the soft tissue than the embodiments of slots or shapes, but may require more force to push the cup 10 through the sheath 100 . Also, complete removal of the sheath 100 (including the tabs at the perforations) may require additional visual acuity during the replacement surgery.
FIG. 10 illustrates another embodiment of a cup-shaped sheath 110 for an acetabular cup 10 . The sheath 110 incorporates a means for acetabular cup penetration comprising a perforation shape 112 . The shape may be in any form and not to be limited to what is shown. For instance, a perforation shape may be comprised of one or more of a triangle, oval, star, polygon, or other multi-sided geometric shape having spline curves.
While the embodiments described above have disclosed many individual forms for the penetration means, it is possible to combine these forms into a single form. For example, a shape similar to the example shown in FIG. 4 may also have a slot or slit extending through remaining portions of the sheath. Such embodiments may allow additional flexibility in the type of material used and the amount of force necessary to push the cup through the sheath.
FIGS. 11 a - 11 c illustrate a method of packaging one embodiment. A sheath 100 is packaged with an acetabular cup 10 . The assembly is packaged (e.g., using a box or container 120 shown in FIG. 11 c ) and then sterilized according to conventional methods. The perforation pattern 102 may be any of the penetration means disclosed herein.
FIGS. 12 a - 12 e illustrate a method of using an embodiment. A packaged sheath 100 and acetabular cup 10 assembly is removed from a container 120 ( FIG. 12 a ). An inserter instrument 12 is inserted into the acetabular cup 10 ( FIG. 12 b ). The inserter 12 inserts the acetabular cup 10 through a body cavity 20 ( FIGS. 12 c - 12 d ) to a prepared acetabulum 24 such that the sheath 100 shields the acetabular cup from contact with “gummy” bio-matter 22 which can clog the outer porous structure of the acetabular cup 10 . At the bottom of the body cavity, the acetabular cup 10 protrudes from or penetrates through a means for acetabular cup penetration ( FIG. 12 d ). Flaps 130 on the sheath 100 part to allow the cup to pass through the sheath 100 . Finally, the sheath 100 is removed or otherwise generally displaced from the acetabular cup 10 , the cup 10 is impacted, and both the sheath 100 and the inserter instrument 12 are removed from the body cavity 20 .
In some embodiments, it may be necessary to change the sizes, shapes, lengths, and widths of the slits, slots, flaps, shoulders, etc. to accommodate various shapes and sizes of acetabular cups, shells, augments, cages, etc. and to allow easy penetration of the acetabular cup through the sheath during impaction.
The sheath may be disposable, flexible, colored, non-colored, opaque, transparent, translucent, lubricated, non-lubricated, anatomically-shaped, non-anatomically shaped, cylindrical, implant conforming or cup-shaped, and may have various cross-sectional types. The sheath may be flanged at the open end and configured to rest on bony portions of the acetabular rim, or may be un-flanged to facilitate insertion and withdrawal. The thickness of the sheath may vary. Means provided to the sheath to allow cup penetration can be configured in different ways as would be expected by one having an ordinary skill in the art. Indicia may be provided on the sheath, such as arrows, trademarks, instructions (e.g., for insertion, disposal, orientation, patient or physician info, model number, product number, identification, etc.), or other forms of indicia. Indicia may be moulded in or provided through the usage of inks or dyes. Sheaths may be incorporated with other instruments as an integral unit, or sheaths may be provided with means for effectively facilitating removal from a body cavity—such means may amount to apertures, locking mechanisms, tangs, shelves or ledges for engagement by a tool, etc. In some instances, it may be desirable to incorporate the sheath with a liner inserter guide as one integral unit such as the inserter guide disclosed in co-pending application “Acetabular Liner Inserter Guide” PCT US2008/055323.
While the sheath has been described as having a formed bottom portion, the top portion may also be similarly formed as opposed to open. This may help to further protect the cup from bio-matter and may further allow the surgeon to reposition the sheath and cup by moving the sheath and cup out of the wound. In packaging the cup, the cup would then pass through one side of the sheath in order to get the cup within the sheath and then be passed through the other side during implantation.
As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.
The embodiments may improve initial bony fixation by preventing clogging of porous or frictional surfaces on an acetabular cup during insertion into a body cavity. The embodiments may further reduce the risk of liner mal-alignment by keeping most of the inside of the acetabular cup free from debris and soft tissue. The embodiments may even further decrease the risk of an acetabular liner dislodging from its acetabular shell by ensuring that all mating portions between a liner and shell are free from bio-matter.
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An acetabular cup and sheath assembly comprises a sheath and an acetabular cup. The sheath is configured to receive the acetabular cup within the sheath. The sheath and acetabular cup together are configured to pass through a surgical wound toward an implantation site. The sheath further comprises a penetration structure for passing the acetabular cup through the sheath when the acetabular cup is proximately close to an implantation site.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a drive circuit and a drive method of a semiconductor laser module that externally modulates carrier light output from a semiconductor laser using an electro-absorption type optical modulator to output the modulated light, in particular, to a drive control technique for compensating for temperature characteristics of the semiconductor laser and the electro-absorption type optical modulator.
[0003] 2. Description of the Related Art
[0004] In various optical communication systems for transmitting optical signals over a long distance, there is sometimes used a semiconductor laser module in which a semiconductor laser and an external modulator of electro-absorption type are integrated with each other, since such a semiconductor laser module enables to increase a transmission distance compared with a semiconductor laser of direct modulation type. In the aforementioned semiconductor laser module, operation characteristics of the semiconductor laser and the electro-absorption type optical modulator (hereinafter referred to as EA modulator) each has dependence on temperature. Therefore, in order to hold optical output power in stable, it is necessary to stabilize a module temperature or to control a drive condition according to a temperature change.
[0005] In a conventional drive control of a semiconductor laser module having an EA modulator, such a method is typical in that, for example, by using an electronic cooling device such as a Peltier device and a temperature detection device such as a thermistor integrated with each other in a module, a current to be supplied to the Peltier device is controlled so that a resistance value of the thermistor is maintained to be constant, to hold the temperature of a semiconductor laser and the EA modulator to be constant. In this case, the EA modulator is driven by a constant modulated electric signal and at the same time, a constant drive current or a drive current to make a back power monitor current constant is supplied to the semiconductor laser, thereby achieving a stable optical output. The drive control method described above, however, has a disadvantage that since the Peltier device needs to be driven, the power consumption is increased and also a package size of the module is made to be large.
[0006] To cope with this problem, a semiconductor laser module using an EA modulator which is not provided with a Peltier device, has recently been under development. According to this semiconductor laser module, both the reduction of power consumption and the miniaturization can be achieved by eliminating the need of a Peltier device, although there is a need of stabilizing optical output power by controlling a bias voltage of the EA modulator or a drive current of the semiconductor laser according to a temperature change. Also, since this module is of an external modulation system using the EA modulator, it is possible to obtain an optical output having a small amount of chirping.
[0007] As a conventional drive control technique applicable to such a semiconductor laser module without the Peltier device as described above, a drive circuit for an EA modulator is disclosed in Japanese Unexamined Patent Publication No. 11-119176. In this drive circuit, an anode voltage of the EA modulator is detected and according to the detection result, a bias voltage of the EA modulator is controlled, so that an applied voltage to the EA modulator is maintained to be constant even if a temperature change or a change with age occurs.
[0008] However, in the case where the semiconductor laser module provided with EA modulator without the Peltier device is driven by applying the conventional control technique as described above, although the bias voltage of the EA modulator is controlled according to the temperature change and the like, since the EA modulator is driven by a constant modulated electric signal, an optical output waveform of the semiconductor laser module is considerably deteriorated.
[0009] [0009]FIG. 16 is a diagram showing temperature dependence of operating characteristics of a typical EA modulator. In FIG. 16, each characteristic curve represents a relation between power Pf of an optical signal output from the EA modulator and an applied voltage Vea to the EA modulator at each of temperatures 0° C., 25° C. and 75° C. In FIG. 16, if a modulated electric signal of a waveform as shown in the lower left part is applied to drive the EA modulator, since the optical output power Pf is changed along each characteristic curve, an optical waveform at 0° C. output from the EA modulator is considerably deteriorated as compared with an optical waveform at 75° C. as shown in the upper right part. Even if the bias voltage is controlled according to the temperature change as in the conventional technique so that the EA modulator operates in a region where the characteristic curve has the large inclination and is changed substantially linearly, since the inclination or the distortion of the characteristic curve in each operating region differs from each other depending on the temperature, an extinction ratio or a duty of the optical output waveform is changed depending on temperature when the EA modulator is driven by the modulated electric signal in which a modulated amplitude and a cross point are set to be constant.
[0010] Further, since a current generated by absorption of carrier light (hereinafter referred to as a photocurrent) flows through the EA modulator, there is caused a problem in that the applied voltage to the EA modulator deviates, if the photocurrent is changed when controlling a current source for drive controlling the EA modulator. Therefore, for the semiconductor laser module without the Peltier device, it is critically important to realize a drive control method that is not affected by a change in the photocurrent due to the electro-absorption effect, when the temperature change or the change with age is compensated by controlling the electrical drive signal of the EA modulator.
SUMMARY OF THE INVENTION
[0011] The present invention has been accomplished in view of the aforementioned problems, and has an object to provide a drive circuit and a drive method for a semiconductor module provided with an EA modulator, capable of obtaining a stable optical output without a need of controlling a temperature of the module to be constant.
[0012] In order to achieve the object described above, according to the present invention, there is provided a drive circuit for driving a semiconductor module including a semiconductor laser generating carrier light according to a drive current and an electro-absorption type optical modulator outputting an optical signal of which intensity is modulated by absorbing the carrier light output from the semiconductor laser according to the drive voltage, the drive circuit comprising: a laser drive unit; an optical modulator drive unit; a temperature detection unit; and a drive control unit. The laser drive unit supplies a drive current to the semiconductor laser. The optical modulator drive unit applies a drive voltage in which a modulated electric signal is superimposed on a bias voltage, to the electro-absorption type optical modulator. The temperature detection unit detects the ambient temperature of the semiconductor laser and the electro-absorption type optical modulator. The drive control unit controls the drive current supplied by the laser drive unit and the drive voltage applied by the optical modulator drive unit, based on the temperature detected by the temperature detection unit, so that average power, an extinction ratio and an optical cross point of the optical signal output from the semiconductor laser module are constant.
[0013] In the drive circuit of this configuration, a temperature in the semiconductor laser module is detected by the temperature detection unit. Based on this detection result, the drive current supplied to the semiconductor laser is controlled by the laser drive unit, and at the same time, the drive voltage applied to the electro-absorption type optical modulator is controlled by the optical modulator drive unit. Thus, differently from the conventional technique, without the need of controlling the temperature of the module to be constant by a Peltier device or the like, the optical signal having constant average power, a constant extinction ratio and a constant cross point is output from the semiconductor laser module. In this way, it becomes possible to obtain an optical output stable to a temperature change.
[0014] Further, the above drive circuit may be configured to include a photocurrent detection unit detecting a photocurrent generated as a result that the carrier light is absorbed by the electro-absorption type optical modulator, so that the drive current supplied by the laser drive unit and the drive voltage applied by the optical modulator drive unit are controlled by a drive control unit based on the temperature detected by the temperature detection unit and the photocurrent detected by the photocurrent detection unit, so as to hold the average power, the extinction ratio and the cross point of the optical signal output from the semiconductor laser module to be constant.
[0015] With this configuration, the drive current of the semiconductor laser and the drive voltage of the electro-absorption type optical modulator are controlled according to a change in the photocurrent generated in the electro-absorption type optical modulator as well as the temperature change in the semiconductor laser module. Thus, it becomes to make the optical signal output from the semiconductor laser module more stable.
[0016] The above and other objects, features and advantages will be made apparent from the detailed description below in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] [0017]FIG. 1 is a functional block diagram showing a configuration of a first embodiment of a drive circuit of a semiconductor laser module according to the present invention.
[0018] [0018]FIG. 2 is a diagram for explaining a method of controlling an applied voltage to an EA modulator in the first embodiment.
[0019] [0019]FIG. 3 is a circuit diagram showing a specific example of the first embodiment.
[0020] [0020]FIG. 4 is a circuit diagram showing another specific example of the first embodiment.
[0021] [0021]FIG. 5 is a diagram showing specific examples of a DAC shown in FIG. 4.
[0022] [0022]FIG. 6 is a diagram showing a specific example of a table stored in a ROM shown in FIG. 4.
[0023] [0023]FIG. 7 is a graph showing an example in which a set value in the ROM table is obtained by a complement using a linear approximate expression.
[0024] [0024]FIG. 8 is a graph showing an example in which the set value in the ROM table is obtained by a complement using an exponential approximate expression.
[0025] [0025]FIG. 9 is a graph showing an example in which the set value in the ROM table is obtained by a complement using a polynomial approximate expression.
[0026] [0026]FIG. 10 is a graph showing an example in which the set value in the ROM table is obtained by a complement using an inter-data linear approximation.
[0027] [0027]FIG. 11 is a functional block diagram showing a configuration of a second embodiment of a drive circuit of a semiconductor laser module according to the present invention.
[0028] [0028]FIG. 12 is a circuit diagram showing a specific example of the second embodiment.
[0029] [0029]FIG. 13 is a diagram showing a simple model for explaining a relation between an AC component of photocurrent and an applied voltage to an EA modulator in the second embodiment.
[0030] [0030]FIG. 14 is a conceptual diagram showing signal waveforms for explaining the relation between the AC component of photocurrent and the applied voltage to the EA modulator in the second embodiment.
[0031] [0031]FIG. 15 is a circuit diagram showing another specific example of the second embodiment.
[0032] [0032]FIG. 16 is a diagram showing temperature dependence of operating characteristics of a typical EA modulator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Embodiments of the present invention will be described below with reference to the drawings.
[0034] [0034]FIG. 1 is a functional block diagram showing a configuration of a first embodiment of a drive circuit for a semiconductor laser module according to the present invention.
[0035] In FIG. 1, a semiconductor laser module 1 driven by a drive circuit 10 has a structure in which a semiconductor laser (LD) 2 as a light emitting element and an EA modulator 3 made of a semiconductor chip are integrated with each other. The semiconductor laser 2 generates carrier light (fixed light) of intensity corresponding to a drive current supplied by the drive circuit 10 . In this carrier light, forward emission light emitted from the front end face of the semiconductor laser 2 is input to the EA modulator 3 , and backward emission light emitted from the rear end face of the semiconductor laser 2 is input to a monitor photodiode (PD) 4 disposed in the module. A thermistor 5 disposed in the module is a temperature detecting element having a resistance value being changed according to the ambient temperature of the semiconductor laser 2 and the EA modulator 3 .
[0036] The EA modulator 3 absorbs the carrier light according to the drive voltage applied by the drive circuit 10 to output intensity-modulated optical signals. The EA modulator 3 has a characteristic to supply a photocurrent corresponding to absorbance. Each cathode terminal of the semiconductor laser 2 and the EA modulator 3 is connected to a package of the semiconductor laser module 1 , and here, has the earth potential. A resistor 6 electrically connected in parallel to the EA modulator 3 is a terminal resistor for generating a voltage to be applied to the EA modulator 3 based on a signal supplied from the drive circuit 10 . An impedance value of the terminal resistor 6 to a microwave suitable for fast modulation is 50Ω, for example. Although not shown in the figure, the optical signals output from the EA modulator 3 are focused by a lens and coupled to an optical fiber, to thereby become an optical output from the semiconductor laser module 1 .
[0037] The drive circuit 10 comprises, for example, as a configuration to drive control the semiconductor laser 2 , an LD current drive section 11 , a back power detecting section 12 , an APC reference section 13 and a comparison section 14 , and also comprises, as a configuration to drive control the EA modulator 3 , a bias voltage control section 15 , a modulated amplitude control section 16 , a cross point control section 17 , a modulated electric signal output section 18 and a DC terminator 19 . The drive circuit 10 further comprises a temperature detecting section 20 detecting a temperature in the semiconductor laser module 1 according to a resistance value of the thermistor 5 . A signal indicating this detection result at the temperature detecting section 20 is output to the APC reference section 13 , the bias voltage control section 15 , the modulated amplitude control section 16 and the cross point control section 17 , respectively.
[0038] The LD current drive unit 10 generates a drive current to be supplied to the semiconductor laser 2 . This drive current is controlled according to an output voltage of the comparison section 14 comparing an output voltage of the back power detecting section 12 with an output voltage of the APC reference section 13 . The back power detecting section 12 converts a current flowing through the monitor PD 4 into a voltage according to the backward emission light of the semiconductor laser 2 to generate an output voltage corresponding to power of the backward emission light. Here, since a ratio between an optical output from the front end face and an optical output from the rear end face of the semiconductor laser 2 is constant, forward emission light power of the semiconductor laser 2 is detected indirectly by detecting the backward emission light power thereof.
[0039] The APC reference section 13 is for outputting a reference voltage for an optical output power control loop of the semiconductor laser 2 . The reference voltage set by the APC reference section 13 is controlled according to an output signal from the temperature detecting section 20 , as described later. The comparison section 14 compares the output voltage of the back power detecting section 12 and the output voltage of the APC reference section 13 with each other, and outputs a voltage corresponding to a difference between those output voltages to the LD current drive section 11 .
[0040] The bias voltage control section 15 generates a bias voltage to be applied to the EA modulator 3 through an inductor L 1 . This bias voltage is controlled according to the output signal from the temperature detecting section 20 . Impedance in an output portion of the bias voltage control section 15 is sufficiently high relative to a modulated signal band so that a modulated electric signal to be applied to the EA modulator 3 through a capacitor C 1 from the modulated electric signal output section 18 may not flow into the bias voltage control section 15 .
[0041] The modulated amplitude control section 16 outputs to the modulated electric signal output section 18 , a signal for controlling amplitude of the modulated electric signal to be applied to the EA modulator 3 . The setting of modulated amplitude controlled by the modulated amplitude control section 16 is controlled according to the output signal from the temperature detecting section 20 . The cross point control section 17 outputs to the modulated electric signal output section 18 , a signal for controlling a cross point of the modulated electric signal to be applied to the EA modulator 3 . The setting of electric cross point controlled by the cross point control section 17 is also controlled according to the output signal from the temperature detecting section 20 .
[0042] The modulated electric signal output section 18 generates a modulated electric signal having an amplitude and a cross point corresponding to the control signals from the modulated amplitude control section 16 and the cross point control section 17 , and applies the modulated electric signal thus generated to the EA modulator 3 through the capacitor C 1 . The DC terminator 19 is a DC terminal of the modulated electric signal output section 18 . Impedance of an output portion of the DC terminator 19 is also sufficiently high relative to the modulated signal band so that the modulated electric signal may not flow into the DC terminator 19 .
[0043] Next, the description will be given of an operation of the drive circuit for the semiconductor laser module according to the first embodiment.
[0044] In the semiconductor laser module 1 having the EA modulator described above but without a Peltier device, the carrier light is generated in the semiconductor laser 2 in accordance with the drive current supplied from the drive circuit 10 to be input to the EA modulator 3 . The carrier light is absorbed by the EA modulator 3 according to the voltage applied from the drive circuit 10 so that intensity-modulated optical signals are output from the EA modulator 3 . The ambient temperature of the semiconductor laser 2 and the EA modulator 3 driven by the drive circuit 10 in this way is detected by the temperature detecting section 20 according to the resistance value of the thermistor 5 in the module. A signal corresponding to the temperature thus detected by the temperature detecting section 20 is output from the temperature detecting section 20 to the APC reference section 13 , the bias voltage control section 15 , the modulated amplitude control section 16 and the cross point control section 17 , respectively.
[0045] On the driving side of the semiconductor laser 2 in the drive circuit 10 , the output voltage of the APC reference section 13 being the reference voltage of the optical output power control loop is changed in accordance with the output signal from the temperature detecting section 20 , and this output voltage is applied to one of input terminals of the comparison section 14 . The other input terminal of the comparison section 14 is applied with the output voltage of the back power detecting section 12 corresponding to the backward emission light power of the semiconductor laser 2 . Thus, a difference of the output voltage from the back power detecting section 12 from the reference voltage from the APC reference section 13 is obtained, and an output voltage corresponding to the difference is applied to the LD current drive section 11 . In the LD current drive section 11 , a setting value of the drive current to be supplied to the EA modulator 3 from the semiconductor laser 2 is adjusted in accordance with the output voltage from the comparison section 14 so that the output voltage of the back power detecting section 12 coincides with the reference voltage. As a result, carrier light power applied from the semiconductor laser 2 to the EA modulator 3 is feedback controlled to be constant regardless of a temperature change in the module.
[0046] On the driving side of the EA modulator 3 in the drive circuit 10 , on the other hand, an output voltage of the bias voltage control section 15 is controlled in accordance with the output signal from the temperature detecting section 20 , thereby optimizing a DC component (bias voltage) of the voltage to be applied to the EA modulator 3 . Also, output voltages of the modulated amplitude control section 16 and the cross point control section 17 are controlled, thereby optimizing the amplitude and cross point of the modulated electric signal being an AC component of the voltage to be applied to the EA modulator 3 .
[0047] A method of controlling the voltage to be applied to the EA modulator 3 according to the temperature change in the module will be explained with reference to FIG. 2.
[0048] An example in FIG. 2 schematically shows a state of controlling the voltage to be applied to the EA modulator 3 having a temperature characteristic similar to that of the typical EA modulator shown in FIG. 16 in the case where the temperature detected by the temperature detecting section 20 is changed from 75° C. to 25° C. Namely, in the case where the temperature detected by the temperature detecting section 20 is 75° C., an average voltage level (bias voltage) of an applied voltage Vea to the EA modulator 3 is set so that a low level (Von) and a high level (Voff) of the modulated electric signal are changed in a range of about 0V to 0.8V, as shown in the lower left side of FIG. 2, corresponding to a region where a curve indicating the temperature characteristic of the EA modulator 3 has a large inclination and is changed substantially linearly. At this time, the amplitude and cross point of the modulated electric signal are set, respectively, so that a desired extinction ratio and a desired optical cross point (optical waveform duty) can be obtained according to inclination and distortion of the characteristic curve in a driving region. By supplying the applied voltage having such a drive waveform to the EA modulator 3 , an optical signal having a waveform as shown on the upper right side of FIG. 2 is output from the EA modulator 3 .
[0049] In the case where the temperature detected by the temperature detecting section 20 is 25° C., on the other hand, as shown in the lower central part of FIG. 2, the bias voltage of the EA modulator 3 is shifted to a high level according to a change in the characteristic curve of the EA modulator 3 , and at the same time, the amplitude and cross point of the modulated electric signal are adjusted so that the desired extinction ratio and the desired optical cross point can be obtained according to changes in the inclination and distortion of the characteristic curve. As a result, as shown in the upper right part of FIG. 2, in the case of the temperature of 25° C., the EA modulator 3 outputs an optical signal having the same average output power and waveform as those in the optical signal in the case of the temperature of 75° C. Although not shown in the figure, also in the case where the detected temperature is 0° C., the drive voltage in which the bias voltage, the modulated amplitude and the electric cross point are optimized according to the characteristic curve for 0° C. in the same manner as the above, is applied to the EA modulator 3 , so that an optical signal similar to those in the cases of the detection temperatures of 75° C. and 25° C. is output from the EA modulator 3 .
[0050] As described above, the drive current of the semiconductor laser 2 and the drive voltage (the bias voltage, the modulated amplitude and the electrical cross point) of the EA modulator 3 are controlled according to the temperature detected by the temperature detecting section 20 . Thus, it becomes possible to control the average output power, the extinction ratio and the optical cross point of the optical signal output from the semiconductor laser module 1 to be constant, independently of the ambient temperature, without controlling the temperature of the module with a Peltier device or the like.
[0051] Now, a specific example of the configuration of the drive circuit 10 shown in FIG. 1 will be described. The configuration of the drive circuit according to this invention, however, is not limited to the example described below.
[0052] [0052]FIG. 3 is a circuit diagram showing a specific example of the drive circuit 10 shown in FIG. 1.
[0053] In the configuration example of FIG. 3, the LD current drive section 11 comprises a transistor TR 1 with a collector terminal thereof connected to an anode terminal of the semiconductor laser 2 and an emitter terminal thereof connected through a resistor R1 to a negative supply voltage (−V) terminal, and a differential amplifier A 1 that is applied with the emitter voltage of the transistor TR 1 at one input terminal thereof to apply an output voltage thereof to a base terminal of the transistor TR 1 . The back power detecting section 12 comprises a resistor R2 with one end thereof connected to the monitor photodiode 4 of the semiconductor laser module 1 and the other end thereof grounded.
[0054] The APC reference section 13 comprises resistors R3, R4 connected in series between a positive supply voltage (+V) terminal and an earth terminal, and a differential amplifier A 2 with one input terminal thereof applied with a voltage at a connection between the resistors R3, R4 and the other input terminal thereof applied with the output signal of the temperature detecting section 20 . The temperature detecting section 20 comprises a resistor R 21 with one end thereof connected to the thermistor 5 and the other end thereof grounded. The comparison section 14 comprises a differential amplifier A 3 with one input terminal thereof applied with a voltage at a connection between the monitor photodiode 4 and the resistor R2 and the other input terminal thereof applied with an output voltage of the differential amplifier A 2 .
[0055] The bias voltage control section 15 comprises, here, resistors R 5 , R 6 , differential amplifiers A 4 , A 5 and a transistor TR 2 . The resistors R 5 , R 6 are connected in series between the positive supply voltage terminal and the earth terminal. The differential amplifier A 4 is applied with a voltage at a connection between the resistors R 5 , R 6 at one input terminal thereof and is applied with the output signal of the temperature detecting section 20 at the other input terminal thereof. The transistor TR 2 has an emitter terminal connected to the anode terminal of the EA modulator 3 through an inductor L 1 and a collector terminal connected to the negative supply voltage terminal. The differential amplifier A 5 is applied with an output voltage of the differential amplifier A 4 at one input terminal thereof and is applied with an emitter voltage of the transistor TR 2 at the other input terminal thereof, to apply an output voltage a base terminal of the transistor TR 2 .
[0056] The amplitude modulation control unit 16 comprises, here, resistors R 7 to R 9 , differential amplifiers A 6 , A 7 and a field effect transistor FET 1 . The resistors R 7 , R 8 are connected in series between the positive supply voltage terminal and the earth terminal. The differential amplifier A 6 is applied with a voltage at a connection between the resistors R 7 , R 8 at one input terminal thereof and is applied with the output signal of the temperature detecting section 20 at the other input terminal thereof. The field effect transistor FET 1 is connected between one end of the resistor R 9 and source terminals of field effect transistors FET 2 , FET 3 constituting a differential pair of the modulated electric signal output section 18 described later, to operate as a current source. The other end of the resistor R 9 is connected to the negative supply voltage terminal. The differential amplifier A 7 is applied with a voltage at a connection between the field effect transistor FET 1 and the resistor R 9 at one input terminal thereof and is applied with an output voltage of the differential amplifier A 6 at the other input terminal thereof, to apply an output voltage to a gate terminal of the field effect transistor FET 1 .
[0057] The cross point control section 17 comprises, here, resistors R 10 to R 17 , a differential amplifier A 8 , an amplifier a 1 and capacitors C 2 , C 3 . The resistors R 10 , R 11 are connected in series between the positive supply voltage terminal and the earth terminal, and the resistors R 12 , R 13 and the resistors R 14 , R 15 , are similarly connected in series between the positive supply voltage terminal and the earth terminal. The differential amplifier A 8 is applied with a voltage at a connection between the resistors R 10 , R 11 at one input terminal thereof, and is applied with the output signal of the temperature detecting section 20 at the other input terminal thereof. The amplifier al is for amplifying, up to required levels, a data signal and an inverted data signal applied to input terminals thereof through capacitors C 4 , C 5 , to output the amplified data signals, and each end of the resistors R 16 , R 17 is connected between each input terminal of the amplifier a 1 and the capacitors C 4 , C 5 , respectively. Each of the other terminals of the resistors R 16 , R 17 is grounded through the capacitors C 2 , C 3 , respectively. A voltage at a connection between the resistors R 14 , R 15 is applied to a connection between the resistor R 16 and the capacitor C 2 , while a voltage at a connection between the resistors R 12 , R 13 and an output voltage of the differential amplifier A 8 are applied to a connection between the resistor R 17 and the capacitor C 3 .
[0058] The modulated electric signal output section 18 comprises an amplifier a 2 , the field effect transistors FET 1 , FET 2 described above and resistors R 18 , R 19 . The amplifier a 2 amplifies an output signal from the amplifier a 1 up to a required level, and applies an inverted output signal to a gate terminal of the field effect transistor FET 2 , and a non-inverted output signal to a gate terminal of the field effect transistor FET 3 . The resistor R 18 has one terminal connected to a drain terminal of the field effect transistor FET 2 , and the resistor R 19 has one terminal connected to a drain terminal of the field effect transistors FET 3 , and the other terminal thereof are grounded, respectively. Here, a voltage at a connection between the drain terminal of the field effect transistor FET 3 and the resistor R 19 is applied to the anode terminal of the EA modulator 3 through the capacitor C 1 . The DC terminator 19 comprises a resistor R 20 having one end connected to a signal line between the drain terminal of the field effect transistor FET 3 and the capacitor C 1 through an inductor L 2 , and the other end grounded.
[0059] In the drive circuit 10 having such a specific configuration as described above, a voltage value at one end of the resistor R 21 is changed according to a change in the resistance value of the thermistor 5 , so that the temperature change in the semiconductor laser module 1 is detected. This voltage value is transmitted as the output signal of the temperature detecting section 20 to the APC reference section 13 , the bias voltage control section 15 , the modulated amplitude control section 16 and the cross point control section 17 .
[0060] In the APC reference section 13 , a difference between the output voltage of the temperature detecting section 20 and the reference voltage set in accordance with the resistors R3, R 4 , is obtained by the differential amplifier A 2 , and the resultant differential voltage is multiplied by a multiplying factor, to be output to the differential amplifier A 3 . The differential amplifier A 3 compares the detection result of the back power detecting section 12 with the output voltage of the differential amplifier A 2 as a reference. According to the result of this comparison, a base voltage of the transistor TR 1 of the LD current drive section 11 is regulated, so that the drive current of the semiconductor laser 2 is feedback controlled.
[0061] In the bias voltage control section 15 , a difference between the output voltage of the temperature detecting section 20 and the reference voltage set in accordance with the resistors R 5 , R 6 , is obtained by the differential amplifier A 4 . The resultant differential voltage is multiplied by a desired multiplying factor, and thereafter supplied to the differential amplifier A 5 so that a base voltage of the transistor TR 2 l is regulated. Thus, the bias voltage of the EA modulator 3 is controlled according to the temperature change. In the modulated amplitude control section 16 , a difference between the output voltage of the temperature detecting section 20 and the reference voltage set in accordance with the resistors R 7 , R 8 is obtained by the differential amplifier A 6 . The resultant differential voltage is multiplied by a desired multiplying factor, and thereafter supplied to the differential amplifier A 7 so that a gate voltage of the field effect transistor FET 1 is regulated. Thus, the amplitude of the modulated electric signal output from the modulated electric signal output section 18 is controlled according to the temperature change. Further, in the cross point control section 17 , a difference between the output voltage of the temperature detecting section 20 and the reference voltage set in accordance with the resistors R 10 , R 11 , is obtained by the differential amplifier A 8 . The resultant differential voltage is multiplied by a desired multiplying factor, and thereafter supplied to the connection between the resistor R 17 and the capacitor C 3 , so that the cross point of the modulated electric signal is controlled according to the temperature change.
[0062] As described above, according to the specific example of the drive circuit 10 shown in FIG. 3, the drive current of the semiconductor laser 2 and the drive voltage of the EA modulator 3 can be controlled linearly with respect to the output signal of the temperature detecting section 20 .
[0063] [0063]FIG. 4 is a circuit diagram showing another specific example of the drive circuit 10 of FIG. 1. The components same as those of the configuration example shown in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.
[0064] The configuration example shown in FIG. 4 is characterized to use a control LSI 21 provided with an analog-to-digital converter (ADC) 21 A, a ROM 21 B and digital-to-analog converters (DAC) 21 C 1 to 21 C 4 , to control the drive current of the semiconductor laser 2 and the drive voltage of the EA modulator 3 .
[0065] In this control LSI 21 , first, an analog voltage value corresponding to the resistance value of the thermistor 5 output from the temperature detecting section 20 is converted into a digital value by the ADC 21 A. Then, in accordance with this digital value, addressing of a table stored in the ROM 21 B is performed, and a set value of each address is read out to be output to the corresponding DACs 21 C 1 to 21 C 4 , respectively. In each DAC, an analog voltage signal corresponding to the set value from the ROM 21 B is generated. Specifically, an output signal of the DAC 21 C, corresponding to the control of the drive current of the semiconductor laser 2 is supplied as the reference voltage in the differential amplifier A 3 of the comparison section 14 . Also, an output signal of the DAC 21 C 2 corresponding to the control of the bias voltage of the EA modulator 3 is supplied as the reference voltage in the differential amplifier AS of the bias voltage control section 15 , and an output signal of the DAC 21 C 3 corresponding to the control of the amplitude of the modulated electric signal is supplied as the reference voltage in the differential amplifier A 7 of the modulated amplitude control section 16 . Further, an output signal of the DAC 21 C 4 corresponding to the control of the cross point of the modulated electric signal is supplied to the connection between the capacitor C 3 and the resistor R 17 of the cross point control section 17 .
[0066] In the control LSI 21 , if the DACs 21 C 1 to 21 C 4 outputs a voltage source output as shown in (A) of FIG. 5, for example, a control voltage output from each of the DACs 21 C 1 to 21 C 4 can be supplied as it is to each corresponding control unit. On the other hand, if the DACs 21 C 1 to 21 C 4 outputs a current source output as shown in (B) of FIG. 5, the control voltage to be supplied to each control unit may be obtained by connecting a resistor for voltage conversion to an output side of each DAC.
[0067] [0067]FIG. 6 shows a specific example of the table stored in the ROM 21 B.
[0068] As illustrated in FIG. 6, in the ROM table, there is recorded an appropriate set value (a value expressed in hexadecimal notation in this case) for each of the DACs 21 C 1 to 21 C 4 at each address corresponding to each digital value converted from the output voltage of the temperature detecting section 20 by the ADC 21 A. For this set value in the ROM table, an optimum value is determined in advance for each control by measuring a characteristic change in the semiconductor laser module 1 at each temperature. Also, in the case where temperature characteristic data of the semiconductor laser module 1 can be obtained for the setting of required temperatures (for example, 0° C., 25° C. and 75° C.), set values for other than the above-mentioned temperatures can be obtained by a complement using an approximate expression based on such data.
[0069] For example, if the temperature characteristic data for three temperatures is obtained, assuming that T: temperature, and a, b, c, y: constants, it is possible to obtain a set value at a desired temperature T by a complement using a linear approximate expression =a·T+b as shown in FIG. 7, a complement using an exponential approximate expression =a·exp(b·T)+c as shown in FIG. 8, or a complement using a polynomial approximate expression =a·x y +b·x y−1 +. . . +c as shown in FIG. 9. Also, as shown in FIG. 10, the characteristics of adjacent data may be individually complemented using the linear approximate expression.
[0070] Although the specific example of the complement has been shown for the case where the measurement points of the temperature characteristic data is three, the present invention is not limited thereto, but it becomes possible to obtain the set values with higher accuracy by using the data at many more measurement points. Also, it is possible to combine different complement methods by using, for example, the linear approximate expression for a given temperature range and the exponential approximate expression for another temperature range.
[0071] As described above, in the specific example of the drive circuit 10 shown in FIG. 4, the drive current of the semiconductor laser 2 and the drive voltage of the EA modulator 3 are controlled in accordance with the set values in the ROM table. Thus, it becomes possible to perform a nonlinear control of the output signal of the temperature detecting section 20 as well as the linear control.
[0072] In the specific example using the control LSI 21 described above, it is possible to adopt an application, for example, of a computation process by a CPU on a portion being controlled in analog by digitizing an input thereto.
[0073] Next, a second embodiment of the drive circuit for the semiconductor laser module according to the present invention will be described.
[0074] [0074]FIG. 11 is a functional block diagram showing a configuration of the drive circuit for the semiconductor laser module in the second embodiment. The components same as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0075] In FIG. 11, the configuration of the semiconductor laser module driven by a drive circuit 10 ′ is basically the same as that of the first embodiment. In this second embodiment, instead of utilizing the monitor photodiode 4 in the semiconductor laser module 1 for controlling the optical output of the semiconductor laser 2 to be constant, detecting the photocurrent generated by the absorption of the carrier light in the EA modulator 3 , and based on a change in the photocurrent, the drive current of the semiconductor laser 2 is controlled and at the same time the modulated amplitude of the applied voltage to the EA modulator is controlled. Therefore, in this embodiment, it is possible to use a semiconductor laser module that is not provided with the monitor photodiode 4 .
[0076] Specifically, the drive circuit 10 ′ comprises a bias current detecting section 22 detecting a DC current that is a combination of the photocurrent in the EA modulator 3 and the current flowing through the terminal resistor 6 . The bias current detecting section 22 converts a detection value of this DC current into a voltage value for a load value of the terminal resistor 6 , to output it to a DC photocurrent detecting section 23 . The DC photocurrent detection section 23 compares an output voltage of the bias voltage control section 15 similar to that of the first embodiment with an output voltage of the bias current detecting section 22 , and based on a comparison result, detects a DC component of the photocurrent flowing through the EA modulator 3 , to output a voltage signal corresponding to a detected value to the comparison section 14 .
[0077] The comparison section 14 that is supplied with an output voltage of a DC photocurrent setting section 24 generating a voltage corresponding to a set value of the DC component of the photocurrent at the time of operation of the semiconductor laser module 1 , obtains a difference between an output voltages of the DC photocurrent detecting section 23 and the DC photocurrent setting section 24 , to supply, to the LD current drive section 11 , an output voltage multiplied by the difference.
[0078] Also, the drive circuit 10 ′ comprises a high level detecting section 25 and a low level detecting section 26 , detecting a high-level voltage and a low-level voltage, respectively, of the modulated electric signal to be applied to the EA modulator through the capacitor C 1 from the modulated electric signal output section 18 . The detection results at the high level detecting section 25 and the low level detecting section 26 are sent to a peak detecting section 27 . The peak detecting section 27 obtains a difference between output voltages of the high level detecting section 25 and the low level detecting section 26 , and detects the amplitude of the modulated electric signal applied to the EA modulator 3 , to output a signal indicating the detection result to the AC photocurrent detecting section 28 .
[0079] The AC photocurrent detecting section 28 that is supplied with an output voltage of the modulated amplitude monitor section 29 detecting the modulated amplitude set by the modulated amplitude control section 16 similar to that of the first embodiment, obtains a difference between an output voltage of the peak detecting section 27 and the output voltage of the modulated amplitude monitor section 29 , and detects an AC component of the photocurrent flowing through the EA modulator 3 , to output a voltage corresponding to that time to the comparison section 30 .
[0080] The comparison section 30 that is supplied with an output voltage of the AC photocurrent setting section 31 generating a voltage corresponding to a set value of the AC component of the photocurrent at the time of operation of the semiconductor laser module 1 , obtains a difference between output voltages of the AC photocurrent detecting section 28 and the AC photocurrent setting section 31 , to supply an output voltage multiplied by the difference to the modulated amplitude control section 16 .
[0081] The components other than the above described components of the drive circuit 10 ′ in the second embodiment are similar to the corresponding components of the drive circuit 10 in the first embodiment.
[0082] A specific example of a configuration of the drive circuit 10 ′ shown in FIG. 11 will be described. The present invention, however, is not limited to the example of the drive circuit described below.
[0083] [0083]FIG. 12 is a circuit diagram showing the specific example of the drive circuit 10 ′ described with reference to FIG. 11. The components the same as those in the configuration example of FIG. 3 are denoted by the same reference numerals, respectively, and the description thereof is omitted.
[0084] In the configuration example shown in FIG. 12, the bias current detecting section 22 comprises a resistor R 22 inserted between the collector terminal of the transistor TR 2 and the negative supply voltage (−V) terminal of the bias voltage control section 15 , and a differential amplifier A 9 applied with voltages across the resistor R 22 at input terminals thereof. The DC photocurrent detecting section 23 comprises a differential amplifier A 10 applied with the emitter voltage of the transistor TR 2 of the bias voltage control section 15 at one input terminal thereof and an output voltage of the differential amplifier A 9 of the bias current detecting section 22 at the other input terminal thereof. The DC photocurrent setting section 24 comprises resistors R 23 , R 24 connected in series between the positive supply voltage (+V) terminal and the earth terminal. A voltage at a connection between the resistors R 23 , R 24 is applied to the one input terminal of the differential amplifier A 3 making up the comparison section 14 . The other input terminal of the differential amplifier A 3 of the comparison section 14 is applied with an output voltage of the differential amplifier A 10 of the DC photocurrent detecting section 23 .
[0085] The high level detecting section 25 comprises a diode D 1 , a resistor R 25 and a capacitor C 6 . The diode D 1 has a cathode terminal connected to the signal line connected to the anode terminal of the EA modulator 3 , and an anode terminal connected to one input terminal of a differential amplifier A 11 making up the peak detecting section 27 . The resistor R 25 and the capacitor C 6 are connected in parallel between the anode terminal of the diode D 1 and the earth terminal. The low level detecting section 26 has a similar configuration to the high level detecting section 25 , and comprises a diode D 2 , a resistor R 26 and a capacitor C 7 . An anode terminal of the diode D 2 is connected to the other input terminal of the differential amplifier A 11 of the peak detecting section 27 .
[0086] The AC photocurrent detecting section 28 comprises a differential amplifier A 12 applied with an output voltage of the differential amplifier A 11 of the peak detecting section 27 at one input terminal thereof. The modulated amplitude monitor section 29 comprises a resistor R 27 inserted between the source terminal of the FET 1 of the modulated amplitude control section 16 and the negative supply voltage terminal, and a differential amplifier A 1 3 applied with voltages across the resistor R 27 at input terminals thereof. An output voltage of the differential amplifier A 1 3 is applied to the other input terminal of the differential amplifier A 12 of the AC photocurrent detecting section 28 . The comparison section 30 comprises a differential amplifier A 14 applied with an output voltage of the differential amplifier A 12 of the AC photocurrent detecting section 28 at one input terminal thereof. The AC photocurrent setting section 31 comprises resistors R 28 , R 29 connected in series between the positive supply voltage terminal and the earth terminal. A voltage at a connection between the resistors R 28 , R 29 is applied to the other input terminal of the differential amplifier A 14 of the comparison section 30 . An output voltage of the differential amplifier A 14 of the comparator 30 is applied to the differential amplifier A 7 of the modulated amplitude control section 16 .
[0087] Next, an operation of the second embodiment described above will be explained.
[0088] First, the description will be given of a control operation performed to maintain the power of the forward emission light of the semiconductor laser 2 to be constant according to the DC component of the photocurrent generated in the EA modulator 3 .
[0089] In the optical output constant control of the semiconductor laser 2 , the output voltage of the temperature detecting section 20 corresponding to the resistance value of the thermistor 5 is multiplied by the bias voltage control section 15 , and the bias voltage to be applied to the EA modulator 3 is controlled with respect to the value of the multiplied voltage. Here, the bias voltage applied to the EA modulator 3 is expressed by Vbias.
[0090] A value Ibais of the current flowing into the bias voltage control section 15 at that time is a sum of the DC component Iphoto_dc of the photocurrent generated as a result that the carrier light is absorbed by the EA modulator 3 and a current Ir flowing through the terminal resistor 6 . In the bias current detecting section 22 , the current value Ibais is voltage converted by a monitor resistor or the like, to be detected, and the detection result is output to the DC photocurrent detecting section 23 . An output voltage V 22 of the bias current detecting section 22 is expressed by the following equation (1) with a voltage conversion gain as G 22 .
V 22 = G 22 ×( Ir+Iphoto — dc ) (1)
[0091] In the DC photocurrent detecting section 23 , a difference between the output voltage Vbias from the bias voltage control section 15 and the output voltage V 22 from the bias current detecting section 22 is obtained, and the difference thus obtained is amplified to a required level. An output voltage V 23 of the DC photocurrent detecting section 23 is expressed by the following equation (2) with a differential amplification gain as G 23 and a resistance value of the terminal resistor 6 as R 6 .
V 23 = G 23 × ( V 22 - V bias ) = G 23 × { G 22 × ( l r + lphoto_dc ) - R 6 × l r } ( 2 )
[0092] Assume that the resistance value R6 of the terminal resistor 6 is set to be equal to the voltage conversion gain G 22 of the bias current detecting section 22 (R6=G22). Then, the output voltage V 23 described above is given by the following equation (3).
V 23 = G 23 × G 22 × Iphoto — dc (3)
[0093] Accordingly, the output voltage V 23 of the DC photocurrent detecting section 23 is a value of multiplying the DC component of the photocurrent. Since the DC component of the photocurrent corresponds to the power of the carrier light input to the EA modulator 3 from the semiconductor laser 2 , it becomes possible to control the optical output power from the semiconductor laser 2 to be constant by feedback controlling the drive current of the semiconductor laser 2 in accordance with the output voltage V 23 of the DC photocurrent detecting section 23 . Here, in the comparison section 14 , a difference of the output voltage V 23 of the DC photocurrent detecting section 23 from a target value indicated by the output voltage of the DC photocurrent setting section 23 is obtained, and a control signal amplified with the difference is output to the LD current drive section 11 from the comparison section 14 . Thus, the drive current of the semiconductor laser 2 is feedback controlled so that the DC component of the photocurrent coincides with the target value.
[0094] Next, the description will be given of a control operation for optimizing the amplitude of the modulated electric signal applied to the EA modulator 3 according to the AC component of the photocurrent generated in the EA modulator 3 .
[0095] In the case where the amplitude of the modulated electric signal applied to the EA modulator 3 is set by a current source as shown in the configuration example of FIG. 12 above, voltages applied according to the photocurrent are different between the case where only the resistor 6 is connected to the modulation electrical output section 18 as a load and the case where the EA modulator 3 and the resistor 6 are connected in parallel to each other as loads. That is, since the photocurrent depends on the absorbance of the EA modulator 3 , an amount of the voltage shift due to the photocurrent is varied with the on/off state of the optical output. Therefore, the amplitude voltage of the modulated electric signal output from the modulated electric signal output section 18 deviates from the value set by the modulated amplitude control section 16 .
[0096] Specifically, as shown by a simple model of FIG. 13, for example, an example is considered where it is assumed that the set value of a constant current source for determining the modulated amplitude is 80 mA, the photocurrent flowing when the optical output is off is 14 mA and the photocurrent flowing when the optical output is on is 6 mA. In this assumption, in the case where the load in which the EA modulator 3 and the resistor 6 are connected in parallel to each other is connected to the modulated electric signal output section 18 , a voltage of −1.65V is applied to the EA modulator 3 at a low level output (optical output is off) as shown in (A) of FIG. 13, and a voltage of 0.15V is applied to the EA modulator 3 when the output is at a high level output (optical output is on) as shown in (B) of FIG. 13. Therefore, the amplitude voltage of the modulated electric signal is 1.80V. On the other hand, a case is considered where only the resistor 6 is connected to the modulated electric signal output section 18 , a voltage of −2.0V is applied to the resistor 6 when the output is at a low level and the voltage of 0.0V is applied to the resistor 6 when the output is at a high level. Thus, the amplitude voltage of the modulated electric signal is 2.0V.
[0097] It will be understood that a deviation amount of the amplitude voltage of the modulated electric signal is dependent on the amplitude ΔIphoto of the photocurrent as shown in FIG. 14, for example. That is, the amplitude voltage Vpp of the modulated electric signal of the case where only the resistor 6 is the load as shown in (A) of FIG. 14, is a difference between a high level voltage Von and a low level voltage Voff (Vpp=Von−Voff). On the contrary, in the case where both the EA modulator 3 and the resistor 6 are loads as shown in (B) of FIG. 14B, an amplitude voltage Vpp of the modulated electric signal can be expressed by the following equation (4) with a value of the photocurrent when the optical output is on: Iphoto_on, and a value of the photocurrent when the optical output is off: Iphoto_off.
Vpp = ( Von + lphoto_on × R 6 ) - ( Voff + lphoto_off × R 6 ) = Von - Voff + ( lphoto_on - lphoto_off ) × R 6 = Von - Voff + Δ lphoto × R 6 ( 4 )
[0098] By detecting the amplitude ΔIphoto of the photocurrent, therefore, it becomes possible to judge the amplitude voltage of the modulated electric signal actually applied to the EA modulator 3 .
[0099] In the configuration example shown in FIG. 12, the high and low level voltage values of the modulated electric signal being applied to the EA modulator 3 are detected by the high level detecting section 25 and the low level detecting section 26 , respectively, and from each detection result, an amplitude voltage Vpp 1 is detected by the peak detecting section 27 . The amplitude voltage Vpp 1 detected by the peak detecting section 27 corresponds to the equation (4) described above. On the other hand, the modulated amplitude monitor section 29 detects an amplitude voltage Vpp 2 corresponding to the case where only the terminal resistance 6 is provided, without the EA modulator 3 . This amplitude voltage is Vpp 2 =Von−Voff.
[0100] In the AC photocurrent detecting section 28 , a difference between the amplitude voltage Vpp 1 detected by the peak detecting section 27 and the amplitude voltage Vpp 2 detected by the modulated amplitude monitor section 29 is obtained, to thereby detect the amplitude ΔIphoto of the photocurrent. An output voltage V 28 of the AC photocurrent detecting section 28 is expressed by the following equation (5) with the differential amplification gain: G 28 .
V 28 = G 28 × ( Vpp 1 - Vpp 2 ) = G 28 × R 6 × Δ l photo ( 5 )
[0101] The output voltage V 28 of the AC photocurrent detecting section 28 is compared with the set value of the AC photocurrent by the comparator 30 , and the comparison result is transmitted to the modulated amplitude control section 16 . Thus, the amplitude of the modulated electric signal is feedback controlled so that the amplitude of the photocurrent becomes the target value.
[0102] By the aforementioned series of control operation, it becomes possible to optimize the amplitude of the modulated electric signal applied to the EA modulator 3 according to the AC component of the photocurrent, to control an extinction ratio of the optical signal output from the EA modulator 3 to be constant.
[0103] As described above, with the drive circuit 10 ′ in the second embodiment, by controlling the drive current of the semiconductor laser 2 according to the DC component of the photocurrent generated in the EA modulator 3 , and at the same time, controlling the amplitude of the modulated electric signal of the EA modulator 3 according to the AC component of the photocurrent, it becomes possible to control the average output power and the extinction ratio of the optical signal output from the semiconductor laser module 1 to be constant without the need of controlling the module temperature with a Peltier device or the like. Also, the bias voltage applied to the EA modulator 3 and the cross point of the modulated electric signal are controlled according to the temperature detected by the temperature detecting section 20 , in the same manner as in the first embodiment. Therefore, the waveform of the optical signal output from the semiconductor laser module 1 can also be controlled to be constant independently of the ambient temperature.
[0104] In the second embodiment described above, as shown in the configuration example of FIG. 12, the specific example has been shown where the bias voltage control section 15 or the like is linearly controlled according to the output voltage of the temperature detecting section 20 . However, similarly to the configuration example shown in FIG. 4, the output voltage of the temperature detecting section 20 may be processed using the control LSI. A specific example of such a configuration is shown in FIG. 15. In the configuration example of FIG. 15, the output signal of the DAC 21 C 1 of the control LSI 21 is supplied to the differential amplifier A 5 of the bias voltage control section 15 , and the output signal of the DAC 21 C 2 is supplied to the cross point control section 17 .
[0105] Also, in the second embodiment, the drive current of the semiconductor laser 2 and the modulated amplitude of the EA modulator 3 have been controlled according to the photocurrent generated in the EA modulator 3 . However, one of the drive current of the semiconductor laser 2 and the modulated amplitude of the EA modulator 3 may be controlled according to the photocurrent, and the other of them may be controlled, similarly to the first embodiment, according to the output signal of the temperature detecting section.
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The present invention aims at providing a drive circuit and a drive method for a semiconductor laser module including an electro-absorption type optical modulator, capable of obtaining a stable optical output without controlling a module temperature to be constant. To this end, the drive circuit of the present invention detects a temperature in the semiconductor laser module comprising a semiconductor laser and an EA modulator, and based on the detected temperature, controls a drive current supplied to the semiconductor laser and a bias voltage and a modulated electric signal applied to the EA modulator, so that average power, an extinction ratio and an optical cross point of an optical signal output from the semiconductor laser module are held to be constant.
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BACKGROUND
1. Field of the Invention
The present invention relates generally to messaging systems, and more particularly to electronic messaging systems.
2. Background of the Invention
Today's work and home lifestyles can be very busy for many families. In many cases, individual family members may be involved in multiple activities. Oftentimes, individual family members may have very little personal interaction. In some such families, a bulletin board, chalk board or other manual messaging systems may be used to provide some means of communication between members of the household. In some households, notes may be placed on the refrigerator or other commonly used appliances. Message areas may include a place for leaving notes of interest to the entire household, such as reminders for group events or grocery lists. In some households, the message area may be divided into various sub-areas allowing messages to be easily targeted to one or more household members.
Such messaging systems are also commonly used in a variety of offices or other work spaces. For example, a bulletin board system may be used to let others in the work place know of an individual's whereabouts. A bulletin board may also be used to post important messages for employees attention.
A problem with the above-described messaging systems in that an individual must be near the location of bulletin board to be able to post or read messages on the board. That is, conventional message systems do not provide a convenient method to manage notes posted in a shared environment from a remote location. For example, if a user is away from home when he or she desires to post a message to the bulletin board, that user would not be able to post the message until he or she returns home. By this time, the intended recipient of the message may have already departed the home, thereby missing the communication from the user. In another example, a message cannot be removed from the messaging area unless the user is physically near the messaging system. Similarly, a user cannot post a new message or update an existing messaging from a remote location.
Another problem with conventional messaging systems is that it is difficult to determine whether or not one or more of the intended recipients have read the note. For example, in conventional bulletin boards, even if a reader of a note initials the note or otherwise marks it to show it has been read, other users of the bulletin board must still physically review the board to receive the notification.
Conventional messaging systems also do not provide convenient means for creating a transportable copy of any messages posted thereon. Currently, if a user wants to take a copy of a message away from the messaging system, the user must manually copy a note onto a separate piece of paper. Alternatively, if the note was posted using a paper that may be removed from the board (e.g., pinned or taped to a bulletin board) the user may physically remove note and take the message away from the messaging system. However, if a note is removed from the message board then others members of the household or workplace will not be able to read the note.
SUMMARY OF THE INVENTION
The present invention uses a broadband-enabled internet connection to provide an always-on interface to a virtual family, group, or office bulletin board system. Family members (or, e.g., associates or co-workers) may use this shared environment to communicate with one another either locally or remotely (e.g., using any email- or other web-capable device). The system allows users to print, reply to messages, and hot link to embedded web uniform resource locators (URLs) from within a posted message.
The present invention also provides the capability to create, share and modify “common notes” (e.g., a shopping list) that can be written to or retrieved by anyone, whether in a remote location or not. Accordingly, the present invention provides systems and methods enabling a user to update the bulletin board whenever a need arises. For example, if a user is on his way home from work when he decides to stop at a grocery store, he may retrieve a current version of the shopping list by sending an email or other command to an application server. The application server responds to the request and sends a copy of the list to the user. Further, the user may send a request to update the bulletin board to reflect his intent to purchase the items from the list. In another example, a user, for example, a child, may be informed at school of some item he needs to bring to school. The child may send a message to update the shopping list with the additional item. In this manner, there is less chance of the child forgetting to inform the parents that an item is needed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing an exemplary user-interface that may be used in an embodiment of the present invention.
FIG. 2 is a schematic diagram showing an exemplary electronic bulletin board according to an embodiment of the present invention.
FIG. 3 is a schematic diagram showing an architecture that may be used to implement an embodiment of the present invention.
FIGS. 4A and 4B are exemplary tables that may be maintained in a customer database in an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention comprises an “always-on” electronic bulletin board system that may be remotely manipulated by users. Remote manipulation may include, for example, reading one or more notes posted on the bulletin board, posting one or more notes to the bulletin board, deleting one or more notes from the bulletin board, acknowledging receipt of a note posted on the bulletin board, and the like. FIG. 1 shows an exemplary display device, communications center 100 , that may be used to display an electronic bulletin board according to an embodiment of the present invention. Communications center 100 may optionally include a memory, a central processing unit and computer programming logic for controlling the device. FIG. 1 shows a display of an exemplary graphical user interface for providing various communications systems via communications center 100 .
An electronic messaging system according to an embodiment of the present invention may be provided as an option, such as message center 102 on communications center 100 . Message indicators, for example indicator 104 , may be used to provide a visual alert to one or more family members that a message has been posted for their attention. As shown in FIG. 1 , message center 102 may include a separate area for each family member (or workplace user) and a collective “family” (or workplace) area. In this embodiment, a user in the household (or workplace) may access the message center (e.g., by clicking on icon 106 ) to manipulate messages in the communications center. As will be described in greater detail herein, remote users may also access the communication center to manipulate messages.
FIG. 2 shows an exemplary graphical user interface that may be displayed in embodiments of the present invention when a user clicks on icon 106 . Alternatively, the interface shown in FIG. 2 may be displayed on communications center 100 when the device is idle. For example, the bulletin board may automatically be displayed in a manner similar to that of a “screen saver” commonly used on personal computer systems. As would be apparent to one of ordinary skill in the art, other visual display layouts may be used to convey the message information to users. For example, a text-based interface may be used in embodiments of the present invention. In another example, the messages may include audio and/or video clips providing multimedia communications via the bulletin board system.
As shown in FIG. 2 , in an exemplary embodiment, messages may be posted to the bulletin board and addressed to particular members of the household (or workplace). For example, message 202 is addressed to “Billy” whereas message 204 is addressed to “Mom.” Similarly, messages may be address to “All” members of the household (or workplace) such as message 206 , or may comprise a universal message, such as grocery list 208 .
In the exemplary embodiment shown in FIG. 2 each message includes a menu bar 210 providing options for manipulating the message. Options may allow a user to reply to a message (“Reply”), print a message to a printer device attached to communications center 100 or another printer device accessible on a network (“Print”), delete a message from the display area (“Delete”), mark a message as read (“Mark”), mail a message to some other system (“Mail”), edit a message (“Edit”) and read extended messages (“More”). Other options may be provided in alternative embodiments of the present invention. Moreover, the menu of options need not be provided individually on each message. That is, a single menu may be used to manipulate selected messages. Alternatively, other user interface options may be implemented to present the menu of options to a user (e.g., “right-clicking” on a message may result in a menu being displayed).
An embodiment of the present invention also allows a user to post messages including links to web pages. For example, message 212 from “Steve” to “Jane” includes a uniform resource locator (URL) that the author wants the recipient to review. When Jane reads message 212 , she may click on the link to view the web page.
An embodiment of the present invention may include additional option buttons such as, for example, buttons 214 and 216 providing other options for the user. In this example, button 214 allows a user to create a new message to be posted on the bulletin board and button 216 allows the user to return to a main screen, such as shown in FIG. 1 .
FIG. 3 shows an architecture that may be used to implement an embodiment of the present invention. In this embodiment, the primary logic for providing a service according to the present invention is provided by application server 300 and customer database 302 . Application server 300 may be any computer system, which would typically include a central processing unit, a volatile memory and a non-volatile memory. Customer database 302 may be part of application server 300 or may be on a different computer system. In this embodiment, customer database 302 includes records mapping a user's email address to the user's bulletin board address. The database may also include an IP address associated with particular users and may include user authentication information. FIG. 4A shows an example of records 400 that may be stored in customer database 302 . The mapping provided by customer database 302 may be used in an embodiment to simplify the displayed names for a sender and recipient of a message, as described below.
In an embodiment implemented as shown in FIG. 3 , a user may post messages to the electronic bulletin board by sending an instruction via an email sent to a specified address. The email is processed by application server 300 which generates a message to send to communications center 100 . The email may be sent from any email-enabled device, including, for example, interactive pager 304 , wireless telephone 306 , wireless personal digital assistant (PDA) 308 , handheld computer 310 , computer 312 , internet appliance 314 , and the like. Moreover, as shown in FIG. 3 , the devices may transmit the email message via any standard data path to which the devices are adapted. For example, devices 304 – 310 may be adapted to transmit email via wireless voice/data network 316 . Network 316 may include one or more wireless application protocol (WAP) gateways and one or more web gateway systems. Similarly, devices 310 – 314 may transmit email via switch 318 and internet service provider (ISP) 320 . Switch 318 may be a central office (CO) switch such as those used in the public switched telephone network, or may be a softswitch used in data networks and voice-over-IP systems. ISP 320 provides connectivity to internet 322 .
Application server 300 may, for example, send the message to client gateway 108 via secure intranet 326 , firewall 324 , ISP 320 and internet 322 as shown in FIG. 3 . It would be apparent to one of ordinary skill in the art that other means of sending the message to gateway 108 may also be used. Although FIG. 3 shows only one ISP and one wireless network providing internet connectivity to each device, there may be multiple ISPs and multiple wireless network service providers as would be apparent to one of ordinary skill in the art. Similarly, there may be multiple switches serving each of devices 310 – 314 or a single switch may be used as shown in FIG. 3 .
Remote Writing (Posting) of Items to Bulletin Board
As noted above, a remote user may post an item (i.e., a message) to the bulletin board system by sending an email message to an address that is routed to application server 300 . Upon receipt of the email message, application server 300 may consult customer database 302 to determine whether or not the sender of the email is an authorized user of the electronic bulletin board. Such an authentication step is an optional procedure and may be carried out in a variety of ways. For example, customer database 302 may comprise a list of authorized sender email addresses from which it accepts bulletin board messages. Alternatively, customer database 302 may include a username and password that must be included in the email message.
In this embodiment, the sender's email message may include an addressee such as, for example, “TO: Billy@joneshome.com” and a sender's address such as, for example, “FROM: Jane@Janeswork.com.” Application server 300 looks up the addressee's domain name in column 402 in of table 400 in customer database 302 to determine the destination address, that is, an address associated with client gateway 108 at the user's home (or workplace). As shown in FIG. 4A , the destination address (column 404 ) may be expressed as any network address, such as for example, an IP address or a domain name, among others. Application server 300 may check to see whether or not the sender is authorized to post messages to an electronic bulletin board associated with this destination address. As described above, this step (if implemented) may involve a lookup of the sender's email address (column 406 ) or may involve verification of a username (column 408 ) and password (column 410 ). Alternatively, in some embodiments, open access may be allowed (i.e., application server accepts all messages received and processes them for posting to the electronic bulletin board).
Application server 300 may format the message for delivery to client gateway 108 and display on communications center 100 . In an embodiment of the present invention, customer database 302 also includes a mapping of email sending and receiving addresses to provide a more personalized messaging system. For example, customer database 302 may include a table such as table 450 shown in FIG. 4B . In this example, a message received from “Jane@Janeswork.com” is formatted for posting on the electronic bulletin board according to the recipient's address. That is, if Jane is sending a message intended for one of her children (Billy or Jane) application server 300 formats the message to identify the sender as “Mom” and the recipient by his or her first name as shown in rows 452 and 454 . However, when a message from “Jane@Janeswork.com” to “Steve@joneshome.com” is received, application server 300 formats the message to be posted to include a sender name “Jane” and a recipient name “Steve” as shown in row 456 . Similarly, a message from Jane to “all@joneshome.com” is routed to “Steve & Kids” from “Mom” as shown in row 458 .
In another embodiment of the present invention, a user may post a message to the bulletin board system by connecting to application server 300 . The connection process may be completed using any suitable network protocol, including, for example, HTTP, Telnet, and the like. Again, there may be an authentication process for verifying the user's rights to access the bulletin board system. Such authentication process may include, for example, checking a list of authorized network addresses that may connect to the server, username and password control, and the like. In this embodiment, the user may be provided a menu of options to select, for example, the sender and receiver names to use for a posted message.
Remote Reading of Bulletin Board Items
Remote retrieval or reading of content on an electronic bulletin board according to an embodiment of the present invention may be accomplished in substantially the same manner as described above. That is, for example, a user may send an email message to application server 300 requesting a download of messages from the bulletin board. In one embodiment, the user may be provided the option of only downloading those items that have not been marked read by the user. In another embodiment, the user may request a subset of messages, for example, only messages addressed to the user. In still other embodiments, the user may be able to select messages from a particular user, messages according to their posting time, or other criteria for identifying messages to be downloaded.
In an embodiment of the present invention, application server 300 maintains a copy of messages sent to client gateway 108 . In this embodiment, download requests may be processed at application server 300 without a need to contact client gateway 108 . In other embodiments, application server 300 does not maintain copies of messages posted to the bulletin board. In this embodiment, when a download request is received, application server sends a retrieval command to client gateway 108 . Client gateway 108 responds to the command and sends requested content either to application server 300 for further processing or directly to the requestor's email address.
In another embodiment of the present invention, a user may read messages or request downloads of messages by logging onto application server 300 using any suitable network protocol as described above. In this embodiment, application server 300 may include, for example, a web server configured to display the bulletin board content via a web browser application. As described above, the user may request all messages, or may select a subset of messages for retrieval.
In an embodiment, application server 300 may check the user's permission to access the bulletin board, as described above. That is, application server 300 may request the user to provide a username and password, or may check the requestor's email or IP address to determine whether or not the request should be honored.
Other Remote Manipulation of Bulletin Board Items
According to an embodiment of the present invention, a user may perform other remote manipulation operations on posted bulletin board items. For example, a user may request removal of an item from a bulletin board. In other embodiments, a user may remotely edit a particular message. Other remote manipulation operations that may be provided in one or more embodiments of the present invention include marking a message as read, replying to a message, changing a position of a posting on the bulletin board, copying a message, mailing a message to another email address, and the like.
In some embodiments, customer database 302 may include access levels for determining which users may perform these or other manipulation operations on one or more messages on the bulletin board. As with other embodiments described herein, the user may be requested to provide user authentication information or application server 300 may use other suitable authentication methods. Furthermore, in some embodiments, the user posting a message on the bulletin board may determine which other users may manipulate the message. For example, a user may “lock” a message to prevent others from deleting it.
Other Alternative Embodiments
In an embodiment of the present invention, special messages may be supported. For example, a special message such as grocery list 208 shown in FIG. 2 may be remotely manipulated. As used herein, grocery list 208 is a “special message” because it need not include an author (i.e., sender) name and need not include an addressee. A user may update grocery list 208 in generally the same manner as described above, except that the user may address the email to, for example, “grocery@joneshome.com.” Application server 300 may format the contents of the email to display a message as shown in FIG. 2 . Note, that because a grocery list requires no “reply”, the menu of options associated with such a message may be customized as shown in the FIG. 2 to eliminate this option. Alternatively, the system may include a “reply” option in the menu.
The foregoing disclosure of the preferred embodiments of the present 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 forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.
Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.
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An electronic bulletin board for use in a shared always-on environment wherein a user may manipulate messages from a remote location. The electronic bulletin board may be implemented via database and programming logic on an application server accessible from any network node, including wireless devices. The always-on environment may be set up on a computer or broadband internet appliance or other communications device. Remote users may perform operations such as updating an existing message, posting a new message, download messages, and the like. The bulletin board also supports shared messages designed for special purposes, for example, an electronic grocery list that is accessible from remote locations.
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TECHNICAL FIELD
[0001] The invention herein resides in the art of foam dispensers wherein a foamable liquid and air are combined to dispense a foam product. More particularly, the invention relates to a dispenser wherein a liquid tube pump is provided as part of a disposable refill unit containing the liquid, and an air pump is provided as part of the dispenser housing.
BACKGROUND OF THE INVENTION
[0002] For many years, it has been known to dispense liquids, such as soaps, sanitizers, cleansers, disinfectants, and the like from a dispenser housing maintaining a refill unit that holds the liquid and provides the pump mechanisms for dispensing the liquid. The pump mechanism employed with such dispensers has typically been a liquid pump, simply emitting a predetermined quantity of the liquid upon movement of an actuator. Recently, for purposes of effectiveness and economy, it has become desirable to dispense the liquids in the form of foam, generated by the interjection of air into the liquid. Accordingly, the standard liquid pump has given way to a foam generating pump, which necessarily requires means for combining the air and liquid in such a manner as to generate the desired foam. However, foam generating pumps are more expensive than liquid dispensing pumps, necessarily increasing the cost of a refill unit that includes the pump mechanism.
[0003] Typically, foam pumps include an air pump portion and a fluid pump portion—the two requiring communication to ultimately create the foam. It has been found that the air pump portion required for pumping the air does not wear out and degrade as quickly as the liquid pump portion required for pumping the liquid. Additionally, the air pump portion mainly comes into contact with air and thus stays more sanitary, making its periodic replacement less necessary than in the case of the liquid pump portion and the foam generating portion of a foam dispenser. Accordingly, it has been determined that it is not as necessary to replace the air pump as it is to replace the liquid pump and foam generating portion of the dispenser when replacement of the refill unit is necessary. Accordingly, there is a need in the art for foam dispensing systems that employ a disposable liquid pump and a more permanent air pump.
SUMMARY OF THE INVENTION
[0004] In light of the foregoing, this invention provides a dispenser including a housing and a refill unit. The housing includes an air bellows having and expanded volume and a compressed volume and retaining its expanded volume when the dispenser is not being actuated. The housing further includes a container support, a pump anvil, and a push bar. The push bar provides a pump plate portion and an air bellows actuator, and is capable of reciprocal movement toward and away from the pump anvil. The refill unit includes a container holding a foamable liquid, and a tube pump fluidly communicating with the foamable liquid in the container. The tube pump includes a collapsible tube, and the flow of foamable liquid into and out of the collapsible tube is regulated by a tube pump inlet valve and a tube pump outlet valve. The container fluidly communicates with the collapsible tube through the tube pump inlet valve. The refill unit further includes a mixing unit, and the collapsible tube communicates with the mixing unit through the tube pump outlet valve. The mixing unit includes an air bellows adaptor that is secured to an air outlet of the air bellows to fluidly communicate with the air bellows through an air bellows valve. The dispenser is actuated by moving the push bar toward the pump anvil, with such movement squeezing the collapsible tube between the push plate portion and the pump anvil to force foamable liquid therein through the tube pump outlet valve and into the mixing unit, such movement also causing the air bellows actuator to move the air bellows to its compressed volume to force air therein through the air bellows outlet valve and into the mixing unit.
[0005] Although the various elements of the dispenser as summarized above include particular elements as part of either a housing or a refill unit, this invention is not limited thereto or thereby, and it should be appreciated that the various dispenser elements may be provided in other ways, provided the various elements interact and function as taught herein.
DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is cross sectional view of an embodiment of a dispenser of this invention; and
[0007] FIG. 2 is a cross sectional view of a mixing cartridge.
DETAILED DESCRIPTION OF THE INVENTION
[0008] With reference to FIG. 1 , the dispenser of this invention is shown and designated by the numeral 10 . The dispenser 10 includes a housing 12 adapted to receive and hold a refill unit 14 . Although the housing may take other forms, in this embodiment, the housing 12 is of the common type that includes a cover 16 secured to a backplate 18 . A container support 20 is provided as part of backplate 18 , here, in the form of a ledge 22 . A pump anvil 24 is provided below the ledge 22 , and an air bellows 26 extends outwardly from backplate 18 below the pump anvil 24 . The cover 16 includes a push bar 27 , which, when the cover 16 is closed on backplate 18 , aligns over both the pump anvil 24 and the air bellows 26 . More particularly, the push bar 27 provides a pump plate portion 28 , which aligns with the pump anvil 24 , and an air bellows actuator 30 that extends toward and connects to air bellows 26 .
[0009] The refill unit 14 provides a container 32 holding a foamable liquid S. It is a collapsible container as known in the art. The container 32 is placed in the housing 12 on the container support 20 . A dispensing tube 34 extends down from the container 16 , and feeds foamable liquid S from container 16 to a tube pump 36 . The tube pump 36 includes a collapsible tube 38 positioned between the pump anvil 24 and the push plate portion 28 of the push bar 27 and is preferably secured to push bar 27 to move therewith. A tube pump inlet valve 40 regulates flow of the foamable liquid S into the collapsible tube 38 , and a tube pump outlet valve 42 regulates the flow of foamable liquid S out of the collapsible tube 38 and into a mixing unit 44 . These valves are shown as common spring biased ball valves, but other valves may be used to join with an air source. The mixing unit 44 includes an air bellows adaptor 46 extending to mate with the air bellows 26 .
[0010] The air bellows 26 includes a bellows body 48 that is sealed to backplate 18 at base 50 , and is open at outlet 52 . The bellows body 48 is corrugated, as at ridges 54 and valleys 56 , and is made of a material that provides the bellows body 48 with the ability to reversibly collapse and extend between a compressed volume and an expanded volume. The air bellows adaptor 46 of the mixing unit 44 is sealed around the outlet 52 of the air bellows 26 , and the air bellows 26 fluidly communicates with the mixing unit 44 through an air bellows valve 59 (again as a ball valve, though not limited thereto) provided as part of the mixing unit 44 .
[0011] The air bellows actuator 30 extends toward air bellows 26 and bypasses the tube pump 36 at an aperture 31 . A mount ridge 60 of bellows body 48 is fed through an aperture 62 in the air bellows actuator 30 so that the air bellows actuator 30 will impact the first ridge 54 when urged in the direction of arrow A.
[0012] When the refill unit 14 is properly mounted in the housing 12 and the cover 16 , the dispenser 10 is actuated to dispense a foam product by moving the push bar 27 in the direction of arrow A. By moving the push bar 27 in the direction of arrow A, the collapsible tube 38 is squeezed between the push plate portion 28 of the push bar 27 and the pump anvil 24 . This forces foamable liquid in the collapsible tube 38 through the tube pump outlet valve 42 and into the mixing unit 44 . This movement of the push bar 27 also causes the air bellows actuator 30 to press against the first ridge 54 of the bellows body 48 , thus compressing the air bellows 26 to its compressed volume to force air therein through the outlet 52 of air bellows 46 and through the air bellows valve 59 into the premix passage 66 of the mixing unit 44 . Thus, foamable liquid S and air mix at the premix chamber 66 to form a coarse mixture. During actuation, this coarse mixture is forced through a mesh screen 68 to homogenize mixture and create a high quality foam product that is dispensed at the outlet 70 . As can be seen in FIG. 2 the mesh screen 68 can be replaced with a mixing cartridge 72 , which includes a hollow tube 74 bounded on both ends by mesh screens 76 and 78 .
[0013] In light of the foregoing, it should be apparent that the present invention improves the art by providing a foam dispenser having a liquid tube pump refill unit that is separate and distinct from an air pump unit, namely an air bellows. While a particular embodiment of this invention has been the focus for purposes of disclosing the invention, it should be appreciated that this invention can be modified in various ways without departing from the general concepts taught herein. Thus, this invention is not to be limited to or by any particular embodiment, rather, the claims will serve to define the invention.
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A foam dispenser includes a housing and a refill unit. The refill unit carries a tube pump for pumping a foamable liquid, and the housing carries an air pump for pumping air. The tube pump and air pump fluidly communicate premixed chamber in a mixing unit to create a foam product when the dispenser is actuated to actuate both the 2 pump and the air pump.
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BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a door apparatus for opening and closing side doors of a train.
A mechanism for opening and closing a door of a train is an essential part for the safety of passengers on the train. Once the door of the train is closed, the door should not be opened accidentally regardless of moving or stationary. Further, the doors must always be held closed with a specific force to prevent rain or wind from entering, and to suppress vibrations. However, when an emergency such as a power failure happens to stop the train and the passengers need to evacuate from the train, it must be possible for a passenger to manually open the door relatively easily. Thus, a train door apparatus must be able to work very reliably. The inventor has already developed a train door apparatus that meets these requirements and applied for a patent (see Japanese Patent Publication (KOKAI) No. 2000-142392).
FIGS. 14 to 17 show a train door apparatus according to Japanese Patent Publication (KOKAI) No. 2000-142392. This apparatus is briefly described below. FIG. 14 is a front view showing an entire train door apparatus. FIG. 15 is an enlarged view of an essential part of the train door apparatus. In FIGS. 14 and 15, two doors 1 and 2 are movably suspended from and supported by a door rail 3 horizontally mounted along a side of a train. The two doors move in opposite directions (left and right in the figure) to open or close the train doorways. The door 1 , shown at left in the figure, is driven by a linear motor 5 as an actuator connected to a moving member 4 of the door 1 .
As shown in FIG. 15, a moving unit 5 a of the linear motor 5 engages the moving member 4 to be able to slide for a predetermined distance ‘x’ in an opening or closing direction (to the right or left in the figure). A compression spring 6 is interposed between the moving unit 5 a and the moving member 4 , as shown in the figure. Thus, the linear motor 5 is connected to the door 1 so that the door can move by the distance ‘x’ in the opening direction thereof.
The right door 2 moves in cooperation with the door 1 via a direction conversion mechanism 7 . As shown in FIG. 15, the direction conversion mechanism 7 is composed of a lower rack 9 connected to the moving member 4 of the door 1 via a connection rod 8 , an upper rack 11 connected to the moving member 4 of the door 2 via a connection plate 10 , and a pinion 12 that simultaneously engages these racks 9 and 11 . The lower rack 9 and the upper rack 11 are guided to be able to slide within a unit case 7 a fixed to the train in the opening or closing direction, and the pinion 12 is supported by a shaft fixed to the unit case 7 a . The opening or closing movement of the door 1 driven by the linear motor 5 is transferred to the door 2 by changing the direction by the direction conversion mechanism 7 .
FIGS. 16 and 17 are detailed views showing a locking mechanism 13 (in FIG. 14) attached to the direction conversion mechanism 7 and pushing/pulling attachments (members) 14 and 15 for locking and unlocking the locking mechanism 13 . FIG. 16 shows a locked state, while FIG. 17 shows an unlocked state. In FIGS. 16 and 17, the pushing attachment 14 and the pulling attachment 15 are attached to a tip of the moving unit of the actuator 5 .
The pushing attachment 14 has a rod-like shape and one end horizontally fixed to the actuator 5 . The pulling attachment 15 with a key-shaped tip is placed on a top surface of the pushing attachment 14 , and has one end joined to the actuator 5 by a pin to rotate and move along the vertical axis. The pulling attachment 15 is urged upward by a compression spring 16 interposed between the pulling attachment 15 and the pushing attachment 14 . A pin 17 with a head is screwed into the pulling attachment 15 while loosely passing through the pushing attachment 14 , and limits an upward rotational range of the pulling attachment. A guide fixture 18 contacts a top surface of the pulling attachment 15 and is attached to a tip of a fixed portion of the linear motor 5 to stop the pulling attachment from rotating upwardly.
The locking mechanism 13 has a slider 19 guided to be able to slide in the directions in which the doors 1 and 2 move; a back spring 20 composed of a compression spring to urge the slider 19 toward the door 2 ; a latch 21 guided to be able to slide vertically; and a locking spring 22 composed of a tension spring to urge the latch 21 downward. The slider 19 has a cam surface 19 a disposed on a top surface thereof having an oblique stage surface, and an engaging protruding portion 19 b provided at a tip thereof. Although not shown in detail, the latch 21 is composed of a vertical latch rod 24 guided to be able to move up or down inside a guide cylinder 23 fixed to a unit case 7 a , and a frame 25 integrated with the latch rod 24 . A roller 26 is rotatably attached to the frame 25 to contact the cam surface 19 a of the slider 19 . The locking spring 22 for urging the latch 21 downward is provided between the frame 25 and the unit case 6 a . As described later, the latch 21 advances or retracts in concert with the opening and closing operations of the doors.
In the door apparatus described above, FIG. 16 shows a state in which the doors 1 and 2 are closed and locked. In this state, a tip of the latch rod 24 advances into an engaging hole 27 in the upper rack 11 , which constitutes an engaging portion of the direction conversion mechanism 7 , thereby locking the sliding motion of the upper rack 11 . Thus, the doors 1 and 2 , linked to the upper rack 11 , will not move.
In this state, the pushing attachment 14 abuts against the engaging protruding portion 19 b of the slider 19 , and the key-shaped portion of the pulling attachment 15 engages the engaging protruding portion 19 b . When a signal is sent to open the door, the moving unit 5 a of the linear motor 5 moves to the left. With the door 1 staying at its closed position, the moving unit 5 a initially moves to the left by a predetermined distance ‘x’ while pushing the compression spring 6 . The pulling attachment 15 pulls the slider 19 via the engaging protruding portion 19 b . At this time, the pulling attachment 15 tries to move upwardly, but it can not open, as it is pressed by the guide attachment 18 .
When the slider 19 is pulled and moved to the left, the roller 26 is pushed onto an upper surface of the cam surface 19 a via the inclined surface thereof as shown in FIG. 17 . Thus, the latch 21 is lifted to withdraw the latch rod 24 from the engaging hole 27 to unlock the upper rack 11 , thereby unlocking the doors 1 and 2 . Once the moving unit 5 a moves by the distance ‘x’, the guide attachment 18 stops pushing the pulling attachment 15 . As a result, the pulling attachment 15 rotates upward by the compression spring 16 and is released from the engaging protruding portion 19 b of the slider 19 . Although the pulling attachment 15 is released, the slider 19 remains at its forward position due to a spring force of the back spring 20 , thereby keeping the roller 26 pushed up.
Subsequently, the moving unit 5 a moves the door 1 leftward to its predetermined open position. Correspondingly, the door 2 linked to the door 1 via the direction conversion mechanism 7 moves to the right to open the doors 1 and 2 . Thereafter, a signal is sent to move the door 1 to the right, and the door 1 moves to its closed position, shown in FIG. 16 . Then, the moving unit 5 a pushes the slider 19 via the pushing attachment 14 . As a result, the roller 26 falls from the upper surface of the cam surface 19 a , and the latch rod 24 advances through the engaging hole 27 in the upper rack 11 to lock the doors again. When the doors need to be opened in an emergency, a handle 28 , shown in FIG. 14, is rotated by 90 degree to pull up the latch 21 via a wire 29 , thereby forcibly unlocking the doors.
In a state where the doors are closed, and the latch is engaged to lock the doors, if a hand or a cloth of a passenger is caught between the doors, the locked doors can not be manually opened. Thus, there is a safety problem associated with the train door apparatus described above.
It is thus an object of the present invention to improve the safety of a train door apparatus in an emergency when the train door apparatus has locked the door while in a closed state.
Further objects and advantages will be apparent from the following description of the invention.
SUMMARY OF THE INVENTION
To attain the above objects, the present invention provides a door apparatus. The door apparatus keeps a door in a semi-locked state rather than a fully locked state, even when the doors are closed, so that the door can be opened manually in a certain extent for a while after the train has left a station. For this purpose, in the present invention, a direction conversion mechanism transmits a movement of one door driven by an actuator to the other door in a converted direction. The direction conversion mechanism has a two-stage engagement portion with a latch. When the latch moves down to the first stage of the engagement portion, the doors become in a semi-locked state so that the door can be opened manually in a predetermined distance. When the latch moves further down to the second stage of the engagement portion, the door is completely locked. A stopper mechanism is provided to stop the latch during the operation. When the door is closed, the stopper mechanism stops the latch at the first stage of the engaging portion. Then, when the train reaches a specified speed or higher, the latch is released and moves through the engaging portion down to the second stage.
As a way for moving the latch in connection with the opening and closing operations of the doors, the actuator is connected to one of the doors to be able to move to open the door in a predetermined distance, as shown in Japanese Patent Application (KOKAI) No. 2000-142392. The apparatus is provided with the slider supported to be able to slide in a door moving direction and having a stage cam surface on a top surface; a back spring for urging the slider toward one of the doors; a roller connected to the latch and contacting the cam surface of the slider; a locking spring for urging the latch toward an engaging portion of the direction conversion mechanism; and pushing/pulling attachments (members) attached to the actuator.
When the doors are closed, the actuator pushes the slider via the pushing attachment. The roller is pushed down from an upper stage of the cam surface by the locking spring, and the latch advances into the engaging portion, thereby locking the doors in a closed state. When the doors are opened, the actuator moves in the predetermined distance in the opening direction to pull the slider via the pulling attachment. The roller is pushed onto the upper stage of the cam surface, thereby withdrawing the latch from the engaging portion to unlock the door.
As another means for moving the latch in connection with the opening and closing operations of the doors, the apparatus may be provided with a locking spring for urging the latch toward the engaging portion of the direction conversion mechanism and a solenoid for driving the latch against a force of the locking spring. In this case, to close the doors, the latch is moved into the engaging portion by the locking spring to lock the doors, whereas to open the doors, the solenoid moves the latch from the engaging portion to unlock the doors.
As yet another means for moving the latch in connection with the opening and closing operations of the doors, the apparatus may be provided with a solenoid for driving the latch to advance into the engaging portion of the direction conversion mechanism or retracts therefrom. In this case, to close the doors, the solenoid moves the latch to enter into the engaging portion to lock the doors, whereas to open the doors, the solenoid moves the latch to withdraw from the engaging portion to unlock the doors.
The stopper mechanism is constituted of a slide piece for abutting against the latch when the latch advances into the engaging hole and a solenoid for moving the slide piece into or out in a latch moving path.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view showing an essential part of a train door apparatus in a semi-locked state, according to an embodiment of the present invention;
FIG. 2 is a front view showing an essential part of the door apparatus in FIG. 1 in a state where the doors are manually opened;
FIG. 3 is a front view showing an essential part of the door apparatus in FIG. 1 in a fully locked state;
FIG. 4 is a front view showing an unlocking operation of the door apparatus in FIG. 1;
FIG. 5 is a front view showing an emergency opening operation of the door apparatus in FIG. 1;
FIG. 6 is a front view showing an essential part of a train door apparatus in a semi-locked state according to the second embodiment of the present invention;
FIG. 7 is a front view showing the door apparatus in FIG. 6 in a fully locked state;
FIG. 8 is a front view showing an unlocking operation of the door apparatus in FIG. 6;
FIG. 9 is a front view showing an emergency opening operation of the door apparatus in FIG. 6;
FIG. 10 is a front view showing an essential part of a train door apparatus in a semi-locked state, according to the third embodiment of the present invention;
FIG. 11 is a front view showing the door apparatus in FIG. 10 in a fully locked state;
FIG. 12 is a front view showing an unlocking operation of the door apparatus in FIG. 10;
FIG. 13 is a front view showing an emergency opening operation of the door apparatus in FIG. 10;
FIG. 14 is a front view showing an entire construction of a conventional door apparatus;
FIG. 15 is an enlarged view showing an essential part of the door apparatus in FIG. 14;
FIG. 16 is a front view showing a locking operation of the door apparatus in FIG. 14; and
FIG. 17 is a front view showing an unlocking operation of, the door apparatus in FIG. 14 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Hereunder, preferred embodiments of the present invention will be explained with reference to the accompanied drawings. In these figures, the same reference numbers denote the parts corresponding to those in the prior art (FIGS. 14 to 17 ).
First, FIGS. 1 to 5 show the first embodiment in which the present invention has been applied to the conventional apparatus of FIG. 16 . FIGS. 1 to 5 is partially sectional front views of a locking mechanism portion (the compression spring 16 and the pin with a head 17 shown in FIG. 16 are omitted). FIG. 1 shows a semi-locked state, FIG. 2 shows a state in which the doors in FIG. 1 are manually opened in a specified distance, FIG. 3 shows a fully locked state, FIG. 4 is an unlocked state, and FIG. 5 shows an emergency unlocked state.
A difference in FIG. 1 from the prior art is that the engaging hole 27 , that engages the latch rod 24 of the direction conversion mechanism 7 , is formed of two stages. The latch rod 24 has an elliptical cross-section, with a larger diameter in the transverse direction in FIG. 1 . The engaging hole 27 engages the latch rod 24 with an appropriate gap, and has a semi-elliptical recess along an outer peripheral surface of the latch rod 24 formed at an upper left of the elliptical through-hole, shown in FIG. 1 . The engaging hole 27 is formed of two stages, namely the first stage 27 a and the second stage 27 b.
A unit case 7 a of the direction conversion mechanism 7 has a stopper mechanism 33 installed thereon. The stopper mechanism 33 is composed of a block-shaped slide piece 31 guided by a slide base 30 to be able to slide in the transverse direction of FIG. 1 and a solenoid 32 for moving the slide piece 31 . The solenoid 32 is composed of a bi-stable polarized electric magnet containing a permanent magnet to generate a stroke in the transverse direction of FIG. 1 . Whenever a switch signal is input, a plunger 34 is reversed and held at the end of the stroke by the permanent magnet. The slide piece 31 slides in and out from a moving path of the latch 21 (the vertical direction in FIG. 1 ). When the slide piece 31 slides in the path, the slide piece 31 abuts against the frame 25 to stop the latch 21 (the frame 25 ) in the middle of advancement, as shown in FIG. 1 . The locking spring 22 is installed on the frame 25 between the latch rod 24 and the stopper mechanism 33 . The other configurations are substantially the same as those of the conventional apparatus in FIG. 16 .
In the door apparatus according to this embodiment, when the actuator 5 drives the doors (see FIG. 5) into the closed position upon a close instruction from a vehicle, the roller 26 falls from the cam surface 19 a , and the latch rod 24 is pulled toward the engaging hole 27 by the spring force of the locking spring 22 . When the close instruction is sent, the stopper mechanism 33 has already moved the slide piece 31 into the moving path of the latch 21 . As shown in FIG. 1, the latch 21 is stopped at a distance ‘a’ from the fully locked position, with the frame. 25 abutting against the slide piece 31 and pressed by the locking spring 22 . At this time, the tip of the latch rod 24 has already entered the engaging hole 27 down to the first stage 27 a , as shown in FIG. 1 (a semi-locked state). The actuator 5 has an encoder for detecting a position of the moving unit 5 a , so that a thrust of the moving unit 5 a can be reduced to, for example, about one-tenths of its normal value before the doors are completely closed.
In the semi-locked state, the doors are pushed in the closing direction with this small force. In this state, the doors can be opened with a hand. When the doors are pushed, the doors open with the upper rack 11 moving to the right in FIG. 1 . The doors are then locked when the latch rod 24 engages the first stage 27 a of the engaging hole 27 . FIG. 2 shows the state where the door can be opened manually. The distance ‘b’ (FIG. 1) in which the upper rack 11 can move may be set, for example, to be 15 to 20 mm. This setting allows the doors to be opened by a double distance (b×2), for example, 30 to 40 mm. Accordingly, when a cloth or a hand of a passenger is caught between the doors, the passenger can pull it free from the doors by pushing the doors.
The semi-locked state in FIG. 1 is maintained while the train is not moving or is moving within a low-speed range, for example, 5 km/hour, after starting. Once the train reaches a specific speed, a switch signal based on a speed signal from the vehicle is sent to the solenoid 32 . The solenoid 32 is reversed to retract the slide piece 31 , i.e. move to the right in FIG. 1 . As a result, the latch 21 is released from the slide piece 31 and further moved down by the spring force of the locking spring 22 . The latch rod 24 moves in the engaging hole 27 from the first stage 27 a to the second stage 27 b , thereby bringing the apparatus into the state shown in FIG. 3 (the fully locked state). In the fully locked state, the upper rack 11 is fully locked by engaging the latch rod 24 , thereby fully locking the doors.
FIG. 4 shows a state where the train has stopped and the doors start to open from the closed state as shown in FIG. 3 . When the doors open, the moving unit 5 a of the actuator 5 moves by the specific distance ‘x’ (see FIG. 17) with the doors closed state, while the pulling attachment 15 pulls the slider 19 to push the roller 26 onto the cam surface 19 a , as described in the prior art. The latch rod 24 , integrated with the roller 26 via the frame 25 , is pushed upward by a distance ‘c’ to push from the engaging hole 27 to unlock the doors as shown in FIG. 4 . Then, the actuator 5 opens the doors. Once the moving unit 5 a of the actuator 5 reaches its fully opened position, the above-described encoder sends a fully opened signal, which is then transmitted to the solenoid 32 . The solenoid 32 is reversed from the state shown in FIG. 3 to move the slide piece 31 to a position corresponding to the state shown in FIG. 1 to be ready for the next operation.
FIG. 5 shows an emergency unlocking operation. In the fully locked state in FIG. 3, the handle 28 is rotated from a position shown by a broken line in FIG. 5 to a position shown by a solid line in FIG. 5 to pull up the frame 25 via the unlocking cable 29 . This causes the latch rod 24 to withdraw from the engaging hole 27 to allow the doors to be fully opened manually.
FIGS. 6 to 9 shows the second embodiment using a solenoid as an unlocking device. FIG. 6 shows a semi-locked state, FIG. 7 shows a fully locked state, FIG. 8 shows an unlocked state, and FIG. 9 shows an emergency unlocking operation. In this embodiment, a solenoid 35 is installed opposite to the frame 25 of the latch 21 instead of the slider 19 , the roller 26 , the pushing attachment 14 , the pulling attachment 15 , and other parts in the embodiment shown in FIG. 1 . The solenoid 35 is also composed of a bi-stable polarized electromagnet so that a plunger 36 moves in the vertical direction of FIG. 6 and is held at the end of the stroke by a permanent magnet.
In the fully locked state of FIG. 7, the plunger 36 of the solenoid 35 is at a retracted position. Upon an open instruction, the plunger 36 pushes up the frame 25 of the latch 21 . As shown in FIG. 8, the latch rod 24 is withdrawn from the engaging hole 27 to unlock the doors. Then, the actuator 5 opens the doors. Once the doors are fully opened, with a fully open signal from the encoder, the stopper 33 is driven to move the slide piece 31 into the moving path of the latch 21 . Subsequently, when a close instruction is sent to close the doors, with a fully close signal from the encoder, the solenoid 35 is switched to move the plunger 36 to retract. Thus, the latch 21 is lowered by the spring force of the locking spring 22 , abuts against the slide piece 31 , and is stopped, thereby bringing the apparatus into the semi-locked state shown in FIG. 6 . The other parts of the construction and operation are the same as those in the embodiment shown in FIGS. 1 to 5 , and the description is thus omitted.
FIGS. 10 to 13 shows the third embodiment. FIG. 10 shows a semi-locked state, FIG. 11 shows a fully locked state, FIG. 12 shows an unlocked state, and FIG. 13 shows an emergency unlocked state. In this embodiment, the locking spring in the second embodiment is omitted. As shown in FIG. 10, the plunger 36 of the solenoid 35 is connected to the frame 25 of the latch 21 via a joining attachment 37 . When the doors are closed, the plunger 36 of the solenoid 35 retracts to pull down the latch 21 to move the latch rod 27 through the engaging hole 27 . Accordingly, the locking spring 22 is not required. Other aspects of the configuration and operation are the same as those in the second embodiment, and the description is thus omitted.
As described above, according to the present invention, the semi-locked state is maintained for some time after the train has left from the station. Accordingly, the door safety function is added to the apparatus in addition to the conventional closing function so that a cloth or a hand of the passenger caught between the doors can be easily released therefrom, thereby improving the passenger safety.
While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.
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A door apparatus for opening and closing two doors supported on a horizontal door rail includes an actuator connected to one of the two doors for driving the same, a direction conversion mechanism connected to the other of the two doors for transmitting a movement of the actuator to the other door to move the same and having an engaging portion formed of a first stage and a second stage, and a locking mechanism having a latch engaging the direction conversion mechanism for locking the two doors and non-engaging the direction conversion mechanism for allowing the two doors to open. The latch engages the first stage of the engaging portion to semi-lock the doors to be able to open manually, and engages the second stage of the engaging portion to lock the doors completely.
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BACKGROUND OF THE INVENTION
1. Field of Invention
This invention generally relates to processing an image. More particularly, this invention is directed to methods and systems that use a median filter to sharpen the edges of objects within an image.
2. Description of Related Art
Imaging devices generally use an electronic sensing device to capture images. Examples of electronic sensing devices include scanners, electrophotographic and videographic devices and medical imaging devices such as x-ray, catscan, NMR and the like. The images can be captured directly from an object, or indirectly from a medium, such as film. The electronic image data is organized and stored as a plurality of pixels which together make up a representation of an entire image. Each pixel is generally represented as one or more bits, such as a byte, of image data defining an image value for that pixel. The image value of each pixel represents a different color or the densities of one or more different colors, or, in a black and white system, a density ranging from black to white.
During capturing and storing an image, inaccurate or imprecise image values are often generated for various pixels within the image. This is particularly a problem around the edges of objects within images. In some edge lines, where there should be a dramatic difference between the image values for pixels on different sides of the edge, soft or blurred edges often occur. An edge can appear soft or blurred for several reasons, including poor focus, movement of the sensing device or of the object (or objects) being sensed, or the physical limitations of the sensing device. On a soft edge, the image color or intensity does not change abruptly from one pixel to the adjacent pixel, but rather shows up as incremental changes over several pixels.
The appearance of an image can often be improved by sharpening the edges of objects within the image. A conventional technique for image sharpening increases the high frequency components of the image through some type of feedback mechanism. This may be accomplished by a convolution with an edge enhancing filter or, alternatively and more efficiently, using error-diffusion techniques.
Median filters are commonly used to filter signals. “The Weighted Median Filter”, D. R. K. Brownrigg, Image Processing and Computer Vision, R. Haralick, ed., Association for Computing Machinery, (1984) and “Adaptive Decimated Median Filtering”, Lale Akurun et al., Pattern Recognition Letters 13, pp 57-62, January 1992, each incorporated herein by reference in its entirety, describe some applications of median filtering.
SUMMARY OF THE INVENTION
The conventional approaches to image sharpening have several limitations. The finite-sized filter that is often used may cause an over-compensation and “ringing” at the edge. This ringing is schematically illustrated in FIGS. 1-3. FIG. 1 illustrates the image values for eight adjacent pixels. The pixels may be vertically, horizontally or diagonally adjacent. The image values shown in FIG. 1 represent the color and/or intensity of each of the eight pixels for the “true” image. The “true” image has an edge between the fourth and fifth pixels. This is represented by the sharp numerical drop in the image values between the first four pixels, which may all be at one color or density, and the last four pixels, which are at a different color or density. However, because a conventional sensing device is often not sensitive enough to record such a sharp change, or because the sharp change is not accurately recorded for some other reason, a soft and/or blurred image edge occurs in the recorded image. For the soft and/or blurred image, the image values for the eight pixels do not change abruptly from one pixel to the next, as in FIG. 1, but, instead, change incrementally over several pixels. In the example illustrated in FIG. 2, for the eight pixels having the “true” image values shown in FIG. 1, the image values actually recorded and stored for these eight pixels change incrementally over the eight pixels.
FIG. 3 illustrates the over-compensation and “ringing” that occurs in the image values of these eight pixels at the edge of an object when using a conventional finite-sized filter to sharpen the image.
Also, due to noise, a sensing device occasionally incorrectly records a “bad” image value for one or more pixels. FIG. 4 illustrates the image values for another set of nine pixels, where the image value for the fifth pixel value contains noise. Noise may be incidentally recorded anywhere in the image. Using one of the conventional sharpening techniques, the noise may actually be enhanced. This is illustrated in FIG. 5, which shows the image values for the nine pixels shown in FIG. 4 after the portion of the image they represent has been sharpened by one of the conventional sharpening techniques.
FIG. 6 shows an unenhanced image that has been captured, stored and printed using conventional techniques. FIG. 7 shows an enlarged portion of the unenhanced conventional image of FIG. 6 showing in detail a recorded soft edge. FIG. 8 shows an image similar to that of FIG. 6 after being enhanced using a conventional enhancing image. FIG. 9 is an enlarged portion of the conventionally enhanced image of FIG. 8, showing the “ringing” at the edge and the enhanced noise, which is located both nearby and away from the edge.
This invention provides systems and methods that improve images without creating ringing artifacts or enhancing noise.
This invention separately provides methods and systems that use a median filtering to improve images without creating ringing artifacts or enhancing noise.
This invention separately provides systems and methods that improve the sharpness of an image by sharpening edges in the image.
This invention separately provides methods and systems in which the median filtering is accomplished by estimating an image value for a selected target pixel by taking the median of the image value measured for the specified target pixel, and of a first image value predicted from the image values of pixels on one side of the selected target pixel and a second image value predicted from the image values of pixels on an opposite side of the selected target pixel.
One exemplary embodiment of the median filter image sharpening methods and systems of this invention includes an image storing device that stores at least some of the image as a plurality of pixels. The median filter compares the measured image value for one of the pixels with image values determined from the image values of neighboring pixels. The filter considers image values from some or all of the eight immediately adjacent pixels (left, right, above, below, diagonal above left, diagonal above right, diagonal below left and diagonal below right), and also of the image values of one or more pixels immediately-adjacent or near to the eight immediately adjacent pixels.
In one exemplary embodiment of the image sharpening methods and systems of this invention, an original image value for a selected target pixel is compared with a first calculated image value determined from, for example, the image values of the two pixels directly to the left of the selected target pixel and the image values for the two pixels directly to the right of the selected target pixel. The median of the three pixels' image values is selected to replace the original image value for the target pixel. This process is repeated for each pixel. Alternatively, this process is repeated for a representative number of pixels. The process can also be repeated using the image values for pixels above and below a selected target pixel, and also for the image values for pixels diagonally adjacent to the selected target pixel. Alternatively, rather than comparing the image value of the selected target pixel individually with the image values of one or more of the vertically, horizontally and diagonally neighboring pixels, a determination based on the image values for all eight of the neighboring pixels, and the image values of pixels that neighbor those eight can be used at the same time.
In another exemplary embodiment of the image sharpening methods and systems of this invention, the image values used to determine the median image value used to replace the image value for the selected target pixel also include the original image values for the adjacent pixels. Thus, if the image value for the horizontally adjacent pixels are used, the replacement image value for the target pixel will be the median of the original image value for the selected target pixel, the image values interpolated from the pixels to the left and right of the target pixel and the original image values of the left and right adjacent pixels. Again, the process can be repeated for vertically and diagonally adjacent pixels, and the process can alternatively be done with all of the neighboring pixels at one time.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments of this invention will be described in detail, with reference to the following drawing figures, in which:
FIG. 1 illustrates the image values of a series of eight adjacent pixels located about a sharp edge in an image;
FIG. 2 illustrates the image values for the eight adjacent pixels of FIG. 1, after being captured and stored as a soft edge;
FIG. 3 illustrates the image values for the eight adjacent pixels of FIG. 2, after the values have been filtered through a conventional enhancement process;
FIG. 4 illustrates the image values of a series of nine pixels after an image has been captured and stored, with the image value of the fifth pixel containing noise;
FIG. 5 illustrates the image values of the nine pixels shown in FIG. 4, after the image values have been filtered through a conventional enhancement process, showing enhancement of the noise in the image value of the fifth pixel;
FIG. 6 is an unenhanced image that has been captured, stored and printed using conventional techniques;
FIG. 7 is an enlarged portion of the unenhanced conventional image of FIG. 8 showing in detail a recorded soft edge;
FIG. 8 is an image similar to that of FIG. 8 after being enhanced using a conventional image enhancing technique;
FIG. 9 is an enlarged portion of the conventionally enhanced image of FIG. 10, showing “ringing” at the edge and enhanced noise away from the edge;
FIG. 10 illustrates one exemplary embodiment of the process for modifying the image value of a pixel at an edge based on the image values of a series of adjacent pixels in accordance with this invention;
FIG. 11 illustrates one exemplary embodiment of the process for modifying a image value of a noisy pixel based on the image values of a series of pixels in accordance with this invention;
FIG. 12 is a functional block diagram outlining in greater detail one exemplary embodiment of the image enhancement system according to this invention;
FIG. 13 is an image enhanced using one method of image enhancement in accordance with one exemplary embodiment of the image enhancing method of this invention;
FIG. 14 is an enlarged portion of the image of FIG. 13, showing in detail the enhancement provided by the exemplary embodiment of this invention;
FIG. 15 is a schematic representation of twenty-five pixels illustrating one exemplary embodiment of the image enhancement system according to this invention.
FIG. 16 is an image enhanced using one method of image enhancement in accordance with one exemplary embodiment of the image enhancing method of this invention;
FIG. 17 is an enlarged portion of the image of FIG. 16 showing in detail the enhancement provided by the exemplary embodiment of this invention;
FIG. 18 is a flow chart outlining one exemplary embodiment of the image enhancement process according to this invention; and
FIG. 19 is a flow chart outlining one other exemplary embodiment of the image enhancement system according to this invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 10 generally illustrates one exemplary embodiment of the image enhancing method and system of this invention such as the median filter system 200 as applied to a series of six adjacent pixels. The six adjacent pixels may be horizontally, vertically or diagonally adjacent. As shown in FIG. 10, the horizontal axis represents the spatial location of the pixels in the image, while the vertical axis represents the image values for the pixels in the image. In particular, as shown in FIG. 10, the selected target pixel 120 at a relative spatial location X has an initial pixel value y. This initial pixel value for the target pixel 120 , for example, is selected to be “revalued” using the systems and methods of this invention to enhance the image containing the target pixel 120 . The systems and methods of this invention can replace the value of each pixel with a median of its current value and two or more predicted values. The predictions can be linear extrapolations of the image values of the target pixel's neighboring pixels. Thus, to enhance the image value y of the target pixel 120 , a straight line from the image value of the pixel 100 at the relative spatial position X−2 through the image value of the pixel 110 at the relative spatial position X−1 is linearly extrapolated to determine a first extrapolated image value y′ at the spatial position X of the target pixel 120 . Similarly, a straight line from the image value of the pixel 140 at the relative spatial location X+2 through the image value of the pixel 130 at the relative spatial location X+1 is linearly extrapolated to determine a second extrapolated image value y″ at the spatial position X of the target pixel 120 . The respective extrapolated values can be considered to be lying along lines tangent to a curve drawn through the image values for the pixels 100 - 150 at the pixels 100 and 140 . The extrapolated lines produce two alternate image values y′ and y″ for target pixel 120 that act to sharpen the edge in comparison to the soft edge of the original of pixel value y for the target pixel 120 .
Then the three values for the image value of the target pixel 120 , the initial image value y, the first extrapolated image value y′ and the second extrapolated image value y″ are compared. The median of the three image values y, y′ and y″ is selected to replace the initial image value y. Thus, one of the extrapolated image values y′ or y″ will, at least some of the time, replace the initial image value y to make the image appear sharper. By repeating this process for each of the original pixel values, the image tends to transform into regions of linearly varying intensities. There is therefore a much smaller tendency for overshooting and ringing along edges.
With regard to the “salt-and-pepper” type of noise shown in FIGS. 4 and 5, rather than enhancing the noise as in the conventional methods, the methods and systems of this invention actually reduce the noise, as illustrated in FIG. 11 . As shown in FIG. 11, target pixel 250 has a value y which contains noise and thus does not accurately reflect the true image value of this pixel of the image. Using the systems and methods of the invention, two straight lines are again extrapolated, from the image values of the pixels 230 and 240 on one side of the target pixel 250 and from the image values of the pixels 260 and 270 on the other side of the target pixel 250 . These two extrapolated lines have extrapolated image values y′ and y″, respectively, at the spatial position X of the target pixel 250 based on the image values and spatial positions X−2 and X−1 of the pixels 230 and 240 and the image values and spatial positions X+1 and X+2 of the pixels 260 and 270 . Again, the median one of the image values y, y′ and y″ is selected and used in place of the original image value y for the target pixel 250 .
FIG. 12 is a functional block diagram of one exemplary embodiment of a system for imaging in accordance with this invention. Images are input from an image data source 300 over a signal line or link 310 to a median filter system 400 . The filtered images are output from the median filter system 400 over a signal line or link 510 to an image data sink 500 . The median filter system 400 includes an input/output interface 410 , a controller 420 , a median data generator 430 , a comparator 440 , a median value selector 450 and a memory 460 . The memory 460 includes an original image data portion 462 and a modified image data portion 128 .
The median data generator 430 extrapolates the image values of the neighboring pixels to the target pixel as described above with respect to FIGS. 10 and 11, and as described below with respect to Equations 1-8 and the methods outlined in FIGS. 18 and 19, and generates the sets of predicted median image values. The comparator 440 compares the predicted image values in the set of predicted median images. The median value selects one of the sets of predicted median image values based on the comparison results generated by the comparator.
In operation, image data is input from the image data source 300 into the input/output interface 410 and stored into the original image data portion 462 of the memory 460 under the control of the controller 420 . The controller 420 picks, one at a time, a number of target pixels from the original image data stored in the original image data portion 462 . The median data generator 430 , under control of the controller 420 , generates, the sets of predicted median image values for each target pixel. The sets or median data for each target pixel are stored in the memory 460 , or they could be forwarded directly to the comparator 440 . The comparator 440 , under control of the controller 420 , inputs pairs of the predicted median image values from the memory 460 and compares them to generate comparison results indicating the relationship between the selected pairs of predicted median image values. The median value selector 450 , under the control of controller 420 , and based on the comparison results of the comparator 440 , selects one of the sets of predicted median image values as the median image value to be used as the image value for the target pixel, and stores the selected median value as the image value of the target pixel in the modified image data portion 464 .
The processed or modified image data stored in modified image data 464 is output by input/output interface, under the control of controller 420 to the image data sink 500 . The image formed by the modified image data can be displayed on a display or printed by a printer onto a recording medium or otherwise stored on a recording medium.
As shown in FIG. 12, the median filter system 400 can be implemented on a programmed general purpose computer. However, the median filter system 200 can also be implemented on a special purpose computer, a programmed microcontroller and peripheral integrated circuit elements, an ASIC or other integrated circuit, a digital signal processor, a hardwired electronic or logic circuit such as a discrete element circuit, a programmable logic device such as a PLD, PLA, FPGA or PAL, or the like. In general, any device, capable of implementing a finite state machine that is in turn capable of implementing the flowcharts above and/or shown in FIGS. 16 and 17, can be used to implement the image sharpening system.
The alterable memory 460 of the image sharpening system, as shown in FIG. 12, can be implemented using static or dynamic RAM. However, the alterable memory 460 can also be implemented using a floppy disk and disk drive, a writable optical disk and disk drive, a hard drive, flash memory or the like.
It should be understood that each of the elements 410 - 460 shown in FIG. 12 can be implemented as portions of a suitably programmed general purpose computer. Alternatively, each of the elements 410 - 460 shown in FIGS. 12 can be implemented as physically distinct hardware circuits within an ASIC, or using a FPGA, a PDL, a PLA or a PAL, or using discrete logic elements or discrete circuit elements. The particular form each of the elements 410 - 460 shown in FIG. 12 will take is a design choice and will be obvious and predicable to those skilled in the art.
Further, it should be appreciated that the signal lines or links 310 or 510 connecting the image data source 300 and the image data sink 500 to the median filter system 400 can be wired or wireless links to a network (not shown). The network can be a local area network, a wide area network, an intranet, the Internet, or any other distributed processing and storage network.
As shown in FIG. 12, the median filter system 400 is connected to the image data source 300 . The image data source 300 provides multi-bit-valued image data. In general, the image data source can be any one of a number of different sources, such as a scanner, a digital copier, a camera, a facsimile device that is suitable for generating electronic image data, or a device suitable for storing and/or transmitting electronic image data, such as a client or server of a network, or the Internet, and especially the World Wide Web.
Similarly, an image data sink 101 can be any known or later developed device that is capable of receiving the enhanced image data output by the median filter system 400 and either storing, transmitting, or displaying the enhanced image data. Thus, the image data sink 101 can be either or both of a channel device for transmitting the enhanced image data for display or storage or a storage device for indefinitely storing the enhanced image data until there arises a need to display or further transmit the enhanced image data.
The channel device can be any known structure or apparatus for transmitting the enhanced image data from the median filter system 400 to a physically remote storage or display device. Thus, the channel device can be a public switched telephone network, a local or wide area network, an intranet, the Internet, a wireless transmission channel, any other distributing network, or the like. Similarly, the storage device can be any known structural apparatus for indefinitely storing the enhanced image data, such as a RAM, a hard drive and disk, a floppy drive and disk, an optical drive and disk, a flash memory or the like.
Moreover, the median filter system 400 can be implemented as software executing on a programmed general purpose computer, a special purpose computer, a microprocessor or the like. In this case, the median filter system 400 can be implemented as a routine embedded in a printer driver, as a resource residing on a server, or the like. The median filter system 400 can also be implemented by physically incorporating it into a software and/or hardware system, such as the hardware and software systems of a printer or a digital photocopier.
The image data source 300 , the median filter system 400 and the image data sink 500 can be combined into an integrated device, such as a digital copier, computer with a built-in printer, or any other integrated device that is capable of producing a hard copy image output. With such a configuration, for example, one or both of the image data source 300 or sink 500 and the median filter system may be contained within a single device.
Determining the extrapolated values for a regular sampling grid is very simple. If the measured intensity or color at position i is V(i) the two extrapolated values at the spatial position X are
V′ ( X )=2 V ( X− 1)− V ( X− 2); and
V″ ( X )=2 V ( X+ 1)− V ( X+ 2),
where:
V(X−1) is the image value at a spatial position one grid step to a first side of the target pixel;
V(X−2) is the image value at a spatial position two grid steps to the first side of the target pixel;
V(X+1) is the image value at a spatial position one grid step to a second side of the target pixel opposite the first side;
V(X+2) is the image value at a spatial position two grid steps to the second side of the target pixel;
V′(X) is the first extrapolated image value at the spatial position X; and
V″(X) is the second extrapolated image value at the spatial position X.
The third value used to determine the median image value is V(X), which is the image value of the target pixel.
Because there are only three image values, the median image value of these three image values can be determined simply by comparing these image values. Given the image values V(X), V′(X) and V″(X), then
if (V(X)>V′ 1 (X))
if (V′ 1 (X)>V″ 2 (X))
the median image value is V′(X)
else if (V″(X)>V(X))
the median image value is V(X)
else
the median image value is V″(X)
else if (V(X)>V″(X))
the median image value is V(X)
else if (V″(X)>V′(X))
the median image value is V′(X)
else
the median image value is V″(X)
Referring to the two-dimensional image shown in FIG. 15, for a target pixel at a spatial location X, Y, the process can be repeated several times to sharpen the edges across various directions. To sharpen vertical edges, the image values of horizontally neighboring pixels are used to generate the predicted image values:
V′ H ( X, Y )=2 V ( X− 1 , Y )− V ( X− 2 , Y ); and (1)
V″ H ( X, Y )=2 V ( X+ 1 , Y )− V ( X+ 2, Y ); (2)
where:
V(X−1, Y) is the image value at a spatial position one grid step to a first horizontal side of the target pixel;
V(X−2, Y) is the image value at a spatial position two grid steps to the first horizontal side of the target pixel;
V(X+1, Y) is the image value at a spatial position one grid step to a horizontal second side of the target pixel opposite the first horizontal side;
V(X+2, Y) is the image value at a spatial position two grid steps to the horizontal second side of the target pixel opposite the first horizontal side;
V′ H (X, Y) is the first extrapolated image value at the spatial position X; and
V′ H (X, Y) is the second extrapolated image value at the spatial position X.
The third value used to determine the median image value is V(X, Y), which is the image value of the target pixel.
To sharpen horizontal edges, the image values of the vertically neighboring pixels are used to generate the predicted image values
V′ V ( X, Y )=2 V ( X, Y− 1)− V ( X, Y− 2); and (3)
V″ V ( X, Y )=2 V ( X, Y+ 1)− V ( X, Y+ 2); (4)
where:
V(X, Y−1) is the image value at a spatial position one grid step to a vertical first side of the target pixel;
V(X, Y−2) is the image value at a spatial position two grid steps to the vertical first side of the target pixel;
V(X, Y+1) is the image value at a spatial position one grid step to a vertical second side of the target pixel opposite the first vertical side;
V(X, Y+2) is the image value at a spatial position two grid steps to a vertical second side of the target pixel opposite the first vertical side;
V′ V (X, Y) is the first extrapolated image value at the spatial position X; and
V″ V (X Y) is the second extrapolated image value at the spatial position X.
The third value used to determine the median image value is V(X, Y), which is the image value of the target pixel.
To sharpen diagonal edges, the image values of diagonally neighboring pixels are used to generate the predicted image values:
V′ D1 ( X, Y )=2 V ( X− 1, Y− 1)− V ( X− 2, Y− 2); and (5)
V″ D1 ( X, Y )=2 V ( X+ 1 , Y+ 1)− V ( X+ 2, Y+ 2); (6)
or
V′ D2 ( X, Y )=2 V ( X− 1, Y+ 1)− V ( X− 2, Y+ 2); and (7)
V″ D2 ( X, Y )=2 V (X+1 , Y− 1)− V ( X+ 2, Y− 2); (8)
where V(X−1, Y−1) is the image value at a spatial position one grid step to a diagonal first side of the target pixel;
V(X−2, Y−2) is the image value at a spatial position two grid steps to the diagonal first side of the target pixel;
V(X+1, Y+1) is the image value at a spatial position one grid step to a diagonal second side of the target pixel opposite the first diagonal side;
V(X+2, Y+2) is the image value at a spatial position two grid steps to the diagonal second side of the target pixel opposite the first diagonal side;
V(X−1, Y+1) is the image value at a spatial position one grid step to a diagonal third side of the target pixel;
V(X−2, Y+2) is the image value at a spatial position two grid steps to the diagonal third side of the target pixel;
V(X+1, Y−1) is the image value at a spatial position one grid step to a diagonal fourth side of the target pixel opposite the third diagonal side; and
V(X+2, Y−2) is the image value at a spatial position two grid steps to the diagonal fourth side of the target pixel;
V′ D1 (X, Y) is the first extrapolated image value at the spatial position X;
V″ D1 (X, Y) is the second extrapolated image value at the spatial position X;
V′ D2 (X, Y) is the third extrapolated image value at the spatial position X; and
V″ D2 (X Y) is the fourth extrapolated image value at the spatial position X.
The third value used (or fifth if both diagonals are used) to determine the median image value is V(X, Y), which is the image value of the target pixel.
This invention can also be used to determine two or more of a first median value based on a horizontal series of pixels including the first pixel, a second median value based on a vertical set of pixels including the first pixel, and at least one third median value based on a diagonal series of pixels. The measured pixel value can then be replaced with the median value of all of the determined medians. Alternatively a standard average value or a weighted average value or some other value based on the determined medians can be used to replace the measured pixel value. The determination of the first median value, the second median value and the at least one third median value can be made simultaneously or sequentially in any order.
Alternatively, rather than linear extrapolations, non-linear extrapolations can be made. For example, second order or third order extrapolations can be made. Also alternatively, more than two neighboring pixels can be taken into account for each extrapolation. Also alternatively, the two or more neighboring pixels for each extrapolation can be located on different sides of the target pixel, rather than on one side of the target pixel.
FIGS. 6 and 7 show an original image captured from video with a blow-up of an edge and flat regions. Soft edges are clearly seen in the enlarged section of FIG. 7 . FIGS. 8 and 9 show the effect of conventional edge enhancement, using the error-diffusion method, on the image. Edge ringing and noise can be seen in the enlarged section of FIG. 9 . In FIGS. 13 and 14, the image has been processed by this invention with passes for the vertical, horizontal, and both diagonal directions. The enlarged section shown in FIG. 13 shows the improved behavior. The edge ringing is not as severe and the noise is actually reduced.
In another exemplary embodiment of the systems and methods of this invention, the image values from which the median image value is selected also includes the two immediate neighbor image values. This limits the edge enhancement to within these two image values when the target pixel lies between them.
For example, again referring to FIG. 15, if it is desired to process a target pixel V(X, Y) in the horizontal direction, the average values of the pixels neighboring this target pixel are V(X, Y−1), V(X, Y−2) on one side and V(X, Y+1), V(X, Y+2) on the other side. Therefore, the set of five image values from which the median value will be selected is:
{V(X,Y); V′(X, Y); (V″(X, Y); V(X, Y−1); and V(X, Y+1)}
where V′(X, Y) and V″(X, Y) are determined above as in Equations 1 and 2. The new image value for V(X, Y) for the target pixel is the median of these five image values.
It is noted that in this exemplary embodiment of the methods of this invention, because the generated image values do not “overshoot” edges, images enhanced using this exemplary embodiment of the methods of this invention will tend not to appear as sharp as in the earlier described embodiment of the methods of this invention. However, the edges in this exemplary embodiment of the methods of this invention will actually be closer to ideal edges, and may provide better images for later processing, such as scaling.
This exemplary embodiment of the methods of this invention can also be used in conjunction with more conventional methods and systems.
FIGS. 16 and 17 show an image that has been processed by this embodiment of this invention with passes for the vertical, horizontal, and both diagonal directions. The enlarged section shown in FIG. 17 again shows the improved behavior. Again, the edge ringing is not severe and the noise is reduced in comparison to FIGS. 8 and 9.
FIG. 18 is a flowchart outlining one exemplary embodiment of a process for median filtering of this invention. Beginning in step S 100 , control continues to step S 110 , where the image data is input. Then, in step S 120 , a first pixel is selected as the target pixel. Next, in step S 130 , one or more sets of neighboring pixels on opposite sides of the target pixel are selected. Control then continues to step S 140 .
In step S 140 , sets of extrapolated image values are generated for the target pixel from the image values of the neighboring pixels on each side of the target pixel for each set of neighborhood pixels. Next, in step S 150 , the median value of each set of extrapolated image values and the image value of the target pixel is identified. Then, in step S 160 , the image value of the target pixel is set to the median value determined in step S 150 . Control then continues to step S 170 .
In step S 170 , the set image value is stored to the pixel location of the target pixel in a modified image. Then, in step S 180 , a determination is made if any more pixels need to be analyzed. If there are additional pixels that need to be analyzed, control continues to step S 185 . Otherwise, control jumps to step S 190 . In step 185 , the next pixel to be analyzed is selected as the target pixel. Control then jumps back to step S 130 . In contrast, in step S 190 , the image data for the modified image is output. Then, in step S 195 , the process ends.
In most applications of this invention, every pixel is analyzed. However, the methods and systems of this invention could be applied selectively using any selection criteria desired. For example, the methods and systems of this invention could be applied only where edges are detected, such as where there are large differences between the values of neighboring pixels, or to areas of high variance, such as where the values of pixels differ greatly from the average value for the pixels in the same neighborhood.
FIG. 19 is a flow chart for the steps of another embodiment of the process of this invention in which the median is selected from the value for the target pixel, extrapolated values from opposite sides of the target pixel and also the image values of pixels on opposite sides of the target pixel. Beginning in step S 200 , control continues to step S 210 , where the image data is input. Then, in step S 220 , a first pixel is selected as the target pixel. Next, in step S 230 , one or more sets of neighboring pixels on opposite sides of the target pixel are selected. Control then continues to step S 240 .
In step S 240 , sets of extrapolated image values are generated for the target pixel from the image values of the neighboring pixels on each side of the target pixel for each set of neighborhood pixels. Next, in step S 250 , the median value of the sets of extrapolated image values, the image values of one or more neighboring pixels on each side of the target pixel and the image value of the target pixel is identified. Then, in step S 260 , the image value of the target pixel is set to the median value determined in step S 250 . Control then continues to step S 270 .
In step S 270 , the set image value is stored to the pixel location of the target pixel in a modified image. Then, in step S 280 , a determination is made if any more pixels need to be analyzed. If there are additional pixels that need to be analyzed, control continues to step S 285 . Otherwise, control jumps to step S 290 . In step S 285 , the next pixel to be analyzed is selected as the target pixel. Control then jumps back to step S 230 . In contrast, in step S 290 , the image data for the modified image is output. Then, in step S 295 , the process ends.
In both methods, vertical, horizontal and diagonal edges can be enhanced. For example, to sharpen the vertical edge, the two predicted values are found by extrapolating the image values of the neighbors horizontally adjacent to the target pixel. To sharpen a horizontal edge, the two predicted values are found by extrapolating the image values of the neighbors vertically adjacent to the target pixel. To sharpen a diagonal edge, the two predicted values are found by extrapolating the image values of the neighbors diagonally using adjacent to the target pixel. The method can be applied consecutively to two or more directions and gain sharpening from each.
While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.
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Image sharpening methods and systems sharpen the edges of objects within images by comparing and replacing the pixel value for a pixel with the median of the original value of the pixel and two values obtained by linear extrapolation of one or more neighboring values on each side of the pixel. By performing the process for all or a plurality of the pixels of a stored image, objects within the image, when output, on a video monitor, paper or other display media, will be provided with sharpened edge characteristics. Thus, the displayed image will include a reduced quantity of edge ringing and a reduced quantity of noise amplification.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119(e) to provisional U.S. Patent Application No. 61/467,361, filed on Mar. 24, 2011, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention is directed generally to a reusable liquid drinking bottle. Specifically, the invention is a multi-part, thermal reusable liquid drinking bottle that can be separated into multiple parts so that it can be easily cleaned by a user's personal physical actions, such as hand cleaning, or with mechanical methods, such as the top and bottom racks within residential and commercial automatic dishwashers.
[0004] 2. Background of the Invention
[0005] Reusable liquid drinking bottles, sometimes known as water bottles, are well known in the art. Exclusive of the open and closing cap, they are typically one piece, substantially cylindrical liquid containment vessels with flat bottoms and having a narrow funnel-shaped drinking spout that engages either a screw-on or pop-up cap. Many of these bottles are comprised of plastic-like material or metal. However, there are a number of problems with these bottles. For example, one cannot effectively clean inside a reusable-drinking bottle given the narrow drinking spout opening where the liquid exits for consumption. Furthermore, and even with top or bottom access to a bottle's inside, the depth and contour of the bottle makes its even more difficult to clean by manual or automatic efforts. This inability to clean inside of a reusable liquid drinking bottle allows dangerous residue, such as mold or bacteria, to grow and reside within the liquid containment vessel, with secondary exposure to the unwanted residual even after cleaning attempts.
[0006] Typically, users will attempt to clean the internal volume of a bottle using a bottlebrush, sponge or dishcloth, among other manual methods. However, these methods are unproductive, inefficient and unsanitary. Furthermore, broad surface cleaning devices such as sponges or scrubbing pads, propelled by the force of the human hand, cannot effectively reach the inner liquid containment vessel of the bottle, again due to the narrow drinking spout and/or the depth of the vessel. The inside lining of these bottles may also be damaged or deteriorated by repeat hand cleanings or originally made of potentially dangerous materials. Also, the hot water and soap cleaning action of an automatic dishwasher is impeded by the same restrictions to the internal volume as the manual means identified above.
[0007] An additional concern of many prior, and current, art plastic-like liquid drinking bottles is that they are made using Bisphenol A (BPA), and other harmful distillates. There is a concern among health care advocates that BPA, and other similar substances, may have detrimental effects on a person's health due to components of the substances leaching into the consumable liquid, sometimes accelerated by exposure to sunlight, heat, repeated handling and manipulation. Therefore, many health care advocates recommend that BPA, and other plastic-like materials, should be removed from reusable liquid drinking bottles or alternatively, that the user should choose, although impractical, glass, or more appropriately high-quality metal liquid drinking bottles, therefore avoiding any malleable plastic-like materials for fear of components or particles thereof leaching into the consumable liquid. Many advocates believe the continued reuse, manipulating and cleaning of these bottles will make it easier for the BPA chemical, and other related plastic-like residuals, to be released into the liquid consumable, and ingested and absorbed by the user's body and is evidenced by the substantial marketing efforts of the status quo to advertise, promote and market “BPA Free”, or words to that effect, reusable liquid drinking bottles.
[0008] There exists a need for a reusable liquid drinking bottle that is free of any potentially harmful chemicals, that is resistant to bacterial growth and other residue due to a feature set that allows the user to implement effective cleaning methods and is practical for primarily human use. Additionally, a liquid drinking bottle that is fully residential and commercial dishwasher safe (top and bottom rack) and easily cleanable by the user is desired and practical for every day and sport related use.
SUMMARY OF THE INVENTION
[0009] Therefore, embodiments of the present invention to provide a drinking bottle with an upper and a lower portion that includes a plurality of separable sections. The separable sections may be horizontally aligned to horizontally separate sections or vertically aligned to vertically separate sections. The liquid drinking bottle body may have a drinking spout that is integral to the drinking bottle body upper and lower portions combined. The bottle is made of top and bottom rack residential and commercial dishwasher, and hand washable, safe materials.
[0010] Embodiments include a drinking bottle that has a top portion integrally attachable to an upper portion of the drinking bottle, commonly called a cap. The drinking bottle top may be removably integral to the drinking bottle. The drinking bottle may have a lower portion that is integrally and removably attachable to the drinking bottle upper portion. The upper portion of the drinking bottle may be comprised of an outer insulating component, combined with an inner liquid containment vessel section. Similarly, the bottom portion of the drinking bottle may be comprised of an outer insulating portion and inner liquid containment vessel section. Once the upper and lower portions of the drinking bottle are fully engaged, the outer insulating portions create an outer insulating shell around the inner liquid containment vessel. Furthermore, once the upper and lower portions of the drinking bottle are fully engaged, a leak proof liquid containment vessel is created.
[0011] Embodiments further include a reusable liquid drinking bottle having multiple sections that can be disengaged and re-engaged to allow for a liquid drinking bottle that can be taken apart, cleaned and put back together. In one embodiment, the liquid drinking bottle is comprised of a top, upper portion, and a bottom portion that are removably attachable to one another. In that embodiment, all three sections can be disengaged from one another and placed in a dishwasher or hand cleaned.
[0012] Other embodiments herein further include a reusable liquid drinking bottle having an upper inner liquid containment vessel and a lower inner liquid containment vessel comprised of stainless steel, or other high quality material that is chemically inert or free of any potential to leach its components into the stored liquid. When the upper inner liquid containment vessel and the lower inner liquid containment vessel are fully engaged a leak proof liquid containment vessel is created. Therefore, once filled, the liquid only comes in contact with the stainless steel, or other safe material, within the liquid containment vessel's top. The stainless steel creates a liquid containment vessel that is resistant to dangerous residue such as mold, bacteria, etc. and is free from leaching issues from plastic-like materials as exemplified by BPA issues now commonly known to consumers and mentioned above.
[0013] Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and following summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the detailed description serve to explain the principle of the invention. No attempt is made to show structural details of the invention in more detail than may be necessary for a fundamental understanding of the invention and the various ways in which it may be practiced. In the drawings:
[0015] FIG. 1 illustrates an expanded view of the multi-part thermal dishwasher compliant reusable liquid drinking bottle according to an embodiment of the invention;
[0016] FIG. 2 illustrates an exploded view of the multi-part thermal dishwasher compliant reusable liquid drinking bottle according to an embodiment of the invention;
[0017] FIG. 3 illustrates the upper and lower outer thermal portions of the multi-part thermal dishwasher compliant reusable liquid drinking bottle according to an embodiment of the invention;
[0018] FIG. 4 illustrates the upper and lower inner liquid containment portions of the multi-part thermal dishwasher compliant reusable liquid drinking bottle according to an embodiment of the invention;
[0019] FIG. 5 illustrates an example of the bottle top, or cap, attached to the multi-part thermal dishwasher compliant reusable liquid drinking bottle according to an embodiment of the invention;
[0020] FIG. 6 illustrate components of the upper and lower portions of the multi-part thermal dishwasher compliant reusable liquid drinking bottle according to an embodiment of the invention.
DETAILED DESCRIPTION
[0021] Embodiments of the invention and the various features and novel details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and details in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments, as the skilled artisan would recognize, even if not explicitly stated herein. The examples and embodiments disclosed herein are intended merely to facilitate and understanding of ways in which the invention may be practiced and to further enable those of skill in the art to practice the embodiments of the invention, which is defined solely by the appended claims and applicable law. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings.
[0022] FIG. 1 shows an expanded view of the multi-part thermal dishwasher compliant reusable liquid drinking bottle (drinking bottle) 100 . The drinking bottle 100 contains several components that are discussed in further detail below. For example, when in ordinary use, liquid is sealed in the drinking bottle with the top (also known as “cap”) 105 . This seal is accomplished with an “O” ring or gasket 108 and in tandem with a cap insert 106 made of the same, or similar, material to the inner liquid vessels 120 and 130 to create a vacuum seal whereby the liquid is also never in contact with the material that makes up the outer layers. A drinking spout 110 typically narrower than the upper portion of the bottle itself is provided for consumption of the stored liquid. An outer upper insulating sleeve 115 surrounds an upper liquid containment vessel 120 . A lower edge 122 of the upper liquid containment vessel 120 engages “O” ring or gasket 125 and along an upper edge 128 of the lower liquid containment vessel 130 . Surrounding the lower liquid containment vessel 130 is the lower insulating sleeve 135 . The lower insulating sleeve 135 has a flat bottom 140 upon which the drinking bottle rests when placed vertically on a flat surface. Along the flat base 140 of the lower insulating sleeve 135 is an affixed flexible expansion point 145 for the insulating sleeve 135 responsive to temperature variations due to liquids in the lower inner liquid containment vessel 130 and extended via thermal conductivity to 115 and 120.
[0023] FIG. 2 illustrates an exploded view of the multi-part thermal dishwasher compliant reusable liquid drinking bottle. For example, as shown in the illustration an outer insulating sleeve 115 can encapsulate the upper portion of the liquid containment vessel 120 . In an embodiment, the upper portion of the liquid containment vessel 120 may be comprised of stainless steel. The stainless steel liquid containment vessel 120 is formed of a seamless contiguous cylindrical tube of steel that tappers off into a significantly narrower drinking spout 110 at the top of the vessel 120 . Note, the drinking spout 110 is manufactured using a roll over edge manufacturing process to create a roll over edge 109 that facilitates contact with the “O” rings or gasket 106 and to facilitate a liquid drinking bottle where the user's lips, or any other part of their mouth, only touches the stainless steel roll over edge 109 of the liquid containment vessel 120 . In an embodiment, the stainless steel containment vessels 120 and 130 are spun manufactured as a single piece of steel. This means that no welding or other materials are used in the making of liquid containment vessels 120 and 130 . The spun manufacturing process further allows for the liquid containment vessels 120 and 130 to have a contiguous design that no surfaces for mold, mildew, bacteria, dirt or debris to build up.
[0024] FIGS. 2 and 4 illustrate the lower portion of liquid containment vessel 120 is open and with a flared flange 122 around the edges for engagement with both a “O” ring or gasket 125 and a top edge 128 of the lower liquid containment vessel 130 . In an embodiment, the “O” ring or gaskets 108 and 125 are comprised of pure, medical grade silicon. The silicon of the “O” rings 108 and 125 along with the stainless steel of the containment vessels 120 , 130 and the stainless steel cap insert 106 are the only materials on the bottle that comes into contact with the consumable liquids stored in the containment vessels 120 , 130 . Although the embodiment discloses the upper portion of the liquid containment vessel 120 being comprised of one continuous portion stainless steel, in other embodiments the upper portion of the liquid containment vessel 120 may comprised of other materials such as a non-toxic plastic material, bamboo, hemp, etc.
[0025] The lower portion of the liquid containment vessel 130 is illustrated in FIGS. 2 and 4 . The lower portion of the liquid containment vessel 130 includes a narrow cylinder tube with a large opening at the top and a flat bottom 132 along the bottom of the container. As described above, in an embodiment, the stainless steel containment vessels 120 and 130 are spun manufactured as a single piece of steel. The liquid containment vessel 130 has a smooth contiguous surface that also has no crevices, creases, etc for mold, mildew, bacteria, dirt or other debris to build up. The upper opening edge of the lower liquid containment vessel 130 is also flared along its top edge 128 , for engaging and compressing both an “O” ring or gasket 125 and a lower edge 122 of the upper liquid containment vessel 120 . In an embodiment, the “O” ring or gasket 125 is comprised of pure, medical grade silicon. This design allows the upper 120 and lower 130 portions of the liquid containment vessel to be detachable from each other for cleaning. However the combination of the gasket 125 and the lower edge 122 of the upper liquid containment vessel engaging and compressing against the upper edge 128 of the lower liquid containment vessel creates a leak proof sealed containment vessel that can easily be taken apart for cleaning.
[0026] The upper 115 and lower 135 insulating sleeves enable the upper 120 and lower 130 portions of the liquid containment vessels to be connected together as illustrated in FIGS. 2 , 3 and 6 . The upper 115 and lower 135 insulating sleeves may be comprised of high-heat resistant nylon or polycarbonate outer shells, which are similar to materials used in cooking utensils. For example, FIGS. 2 and 3 illustrates the upper insulating sleeve 115 encapsulates the upper liquid containment vessel 120 and is substantially the same shape of as the liquid containment vessel 120 , but scaled a bit larger. The upper insulating sleeve 115 further includes threading 117 along its bottom edge for engaging treading along an upper edge of the lower insulating sleeve 135 .
[0027] Similarly the lower insulating sleeve 135 illustrated in FIGS. 2 and 3 is substantially the same shape as the lower liquid containment vessel 130 but a scaled a bit larger. Similar to the upper insulating sleeve 115 , the lower insulating sleeve 135 has an outer threaded portion 133 . The outer threaded portion 133 is designed to engage threating 117 along the bottom edge of the upper insulating sleeve 115 . Along the base 140 of the lower insulating sleeve 135 , a thermal expansion point 145 can be found. The thermal expansion point may be comprised of a silicon “pug” that fills a small opening 145 in the base 140 of the lower insulating sleeve 135 . The thermal expansion point 145 aids in accommodating for the difference in size among the steel liquid containment vessel 130 and the outer insulating sleeve 135 when exposed to varying temperatures associated with the contained liquid and ambient temperatures.
[0028] FIG. 6 illustrates the connected engagement of the upper 115 and lower 135 insulating sleeves. Once the upper and lower insulating sleeves are engaged or screwed together, the upper 120 and lower 130 liquid containment vessels is able to create a leak proof seal with the aid of the “O” ring gasket 125 that is force compressed between a lower edge 122 of upper liquid containment vessel 120 and an upper edge 128 of the lower liquid containment vessel 130 . Once the upper 115 and lower 135 insulting sleeves are screwed together, the force of the compression of the “O” ring or gasket 125 creates a leak proof seal between the upper and lower portions of the of the drinking bottle.
[0029] The insulating sleeves 115 and 130 shown in FIGS. 1-3 , may be comprised of high-heat nylon polycarbonate, plastic, glass, metal or some other material and may encapsulate the drinking vessels 120 and 130 by being heat fused or glued in order to create a seal about its edges. In an embodiment the upper 115 and lower 135 insulating sleeves are thermal (vacuum) sealed relative the to the upper 120 and lower 130 liquid containment vessels to reduce heat transfer between the liquid containment vessel an the ambient environment or the user's hands. Although the connecting threads are shown on an inner portion of the upper inner insulating sleeve 117 they may also be placed along an outer portion of the lower insulating sleeve with corresponding treading 133 on inner portion of the lower insulating sleeve 135 .
[0030] The drinking bottle is sealed using a top or cap 105 as illustrated in FIGS. 1 and 5 . The top 105 has a threaded inner portion 107 . An outer edge of the upper outer insulating sleeve 115 is treaded 110 along exterior portion for engaging the drinking bottle top 105 . The bottle top 105 may further include a silicon “O” ring or gasket 125 for to create a leak proof seal on the between the top and the bottle. The bottle top 105 may includes a hoop opening 102 for engagement with a faster for transport. In another embodiment the bottle top 105 may be tethered to the bottle. Still in other embodiments the bottle top 105 may be a pop up drinking cap that securely screws onto the bottle. In still another embodiment, the bottle top 105 may be a flip top that screws on to the drinking bottle 100 and having a lid that seals tightly onto the bottle. In fact the bottle top 105 may be any bottle top that securely fastens on the drinking bottle 100 to seal it, while allowing the user to easily access the liquid contained therein. In another embodiment, a vacuum seal cap insert 106 , may be employed atop the drinking spout 110 and resting atop a roll over edge 109 of the drinking spout and an “O” ring or gasket 108 . The cap insert 106 is comprised on surgical grade stainless steel and further prevents the consumed liquids from coming into contact with any material other than stainless steel and silicon. This would allow liquids to be vacuum-sealed in their containers to allow the liquids to maintain their temperatures longer and while reducing the likelihood of growth of mold or bacteria in the bottle.
[0031] Therefore, the drinking bottle 100 is designed such that the liquids never actually come into contact with the outer insulating sleeves of the bottle. In an exemplarily embodiment, the inner liquid containment vessel 120 , 130 is made of stainless steel and the lip of the containment vessel is designed such that the roll over edge 109 of the upper portion of the liquid containment vessel 120 covers the top of the thread drinking spout 110 edge the upper insulating sleeve 115 . Therefore, when a user drinks from the drinking bottle 100 , the liquid in the bottle only come into contact with the liquid containment vessel 120 and 130 , the bottle top 105 stainless seal insert 106 and the user's mouth. Thus, if there are any harmful chemicals used to manufacture the outer insulating sleeves 115 and 135 of the drinking bottle 100 , they do not come into direct contact with the liquids stored in the bottle 100 and consumed by the user.
[0032] In an exemplary embodiment, the insulating sleeves 115 and 135 are formed using high heat nylon polycarbonates, fixed over the inner stainless steel containment vessel components 120 and 130 , along with a thermal equalization feature, which allows for use with liquids that are hot (up to 50 degrees Fahrenheit below the boiling point of tap water) to cold (up to 10 degrees Fahrenheit above the freezing point of tap water). However, other high-impact, heat-resistant plastics, glass, metal, bamboo, hemp, etc. materials and manufacturing processes may also be used. Similarly these materials and manufacturing process may be used to manufacturing the inner liquid containment vessel portions 120 and 130 . In an exemplary embodiment, however, the inner liquid containment vessels 120 and 130 are formed from surgical grade stainless steel using spun steel processes. In an embodiment, the containment vessels 120 , 130 are manufactured using the highest quality, non-welded (spun manufacturing) stainless steel (18/8 minimum) during normal use. The “O” rings or gaskets 108 , 125 may be any rubber, plastic, or other waterproof malleable material. However, in the exemplary embodiment, the “O” ring or gasket 108 , 125 is a surgical grade silicone material. In another exemplary embodiment, the outer upper 115 and lower 135 insulating sleeves are vacuum fused and sealed with the upper 120 and lower 130 portions to create vacuum chambers between outer upper 115 and outer lower 135 insulating sleeves along with the corresponding components of the liquid containment vessel 120 and 130 respectively. In an embodiment, the aspect ratio of the drinking bottle can be anywhere from 1×1 to 1×14. In other words, it can be tall and thin, or short and fat. In still another embodiment, the drinking bottle's 100 capacity can be anywhere from 1 to 5000 milliliters.
[0033] When the components of the drinking bottle 100 are separated, they may be hand washed. Alternatively, the separate components of the drinking bottle 100 may be machined washed in a dishwasher. The components of the drinking bottle 100 are fully dishwasher compatible on both the top and bottom racks.
[0034] While the invention has been described in terms of exemplary embodiment, those skilled in the art will recognize that the invention can be practiced with modifications in the sprit and scope of the appended claims. These examples given above are merely illustrative and are not meant to be an exhaustive list of all possible designs, embodiments, application or modifications of the invention.
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Embodiments herein describe a separable, multi-sectioned reusable liquid drinking bottle that can be disassembled for cleaning. The drinking bottle has detachable upper and lower sections and a bottle top. The upper and lower sections are engageable and separable from one another. Both the upper and lower portions of the drinking bottle may be separately encased in a vacuum-sealed insulating layer of insulating material. The bottle portions are designed to engage each other in a leak-proof fashion to create a liquid containment vessel. The upper and lower portions of the drinking bottle create a containment vessel made of stainless steel, such that any liquids placed in the bottle only come in contact with this material that comprises the liquid containment vessel.
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CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This is a continuation application of co-pending application Ser. No. 10/635,076, filed on Aug. 6, 2003, which is a continuation application of application Ser. No. 10/292,160, filed on Nov. 12, 2002, now U.S. Pat. No. 6,659,185 which is a divisional application of application Ser. No. 09/838,604, filed on Apr. 19, 2001, now U.S. Pat. No. 6,523,614.
TECHNICAL FIELD OF THE INVENTION
[0002] This invention relates in general, to the operation of a subsurface safety valve installed in the tubing of a subterranean wellbore and, in particular, to an apparatus and method for locking out a subsurface safety valve and communicating hydraulic fluid through the subsurface safety valve.
BACKGROUND OF THE INVENTION
[0003] One or more subsurface safety valves are commonly installed as part of the tubing string within oil and gas wells to protect against unwanted communication of high pressure and high temperature formation fluids to the surface. These subsurface safety valves are designed to shut in production from the formation in response to a variety of abnormal and potentially dangerous conditions.
[0004] As these subsurface safety valves are built into the tubing string, these valves are typically referred to as tubing retrievable safety valves (“TRSV”). TRSVs are normally operated by hydraulic fluid pressure which is typically controlled at the surface and transmitted to the TRSV via a hydraulic fluid line. Hydraulic fluid pressure must be applied to the TRSV to place the TRSV in the open position. When hydraulic fluid pressure is lost, the TRSV will operate to the closed position to prevent formation fluids from traveling therethrough. As such, TRSVs are fail safe valves.
[0005] As TRSVs are often subjected to years of service in severe operating conditions, failure of TRSVs may occur. For example, a TRSV in the closed position may leak. Alternatively, a TRSV in the closed position may not properly open. Because of the potential for disaster in the absence of a properly functioning TRSV, it is vital that the malfunctioning TRSV be promptly replaced or repaired.
[0006] As TRSVs are typically incorporated into the tubing string, removal of the tubing string to replace or repair the malfunctioning TRSV is required. As such, the costs associated with replacing or repairing the malfunctioning TRSV is quite high. It has been found, however, that a wireline retrievable safety valve (“WRSV”) may be inserted inside the original TRSV and operated to provide the same safety function as the original TRSV. These insert valves are designed to be lowered into place from the surface via wireline and locked inside the original TRSV. This approach can be a much more efficient and cost-effective alternative to pulling the tubing string to replace or repair the malfunctioning TRSV.
[0007] One type of WRSV that can take over the full functionality of the original TRSV requires that the hydraulic fluid from the control system be communicated through the original TRSV to the inserted WRSV. In traditional TRSVs, this communication path for the hydraulic fluid is established through a pre-machined radial bore extending from the hydraulic chamber to the interior of the TRSV. Once a failure in the TRSV has been detected, this communication path is established by first shifting a built-in lock out sleeve within the TRSV to its locked out position and shearing a shear plug that is installed within the radial bore.
[0008] It has been found, however, that operating conventional TRSVs to the locked out position and establishing this communication path has several inherent drawbacks. To begin with, the inclusion of such built-in lock out sleeves in each TRSV increases the cost of the TRSV, particularly in light of the fact that the built-in lock out sleeves are not used in the vast majority of installations. In addition, since these built-in lock out sleeves are not operated for extended periods of time, in most cases years, they may become inoperable before their use is required. Also, it has been found, that the communication path of the pre-machined radial bore creates a potential leak path for formation fluids- up through the hydraulic control system. As noted above, TRSVs are intended to operate under abnormal well conditions and serve a vital and potentially lifesaving function. Hence, if such an abnormal condition occurred when one TRSV has been locked out, even if other safety valves have closed the tubing string, high pressure formation fluids may travel to the surface through the hydraulic line.
[0009] In addition, manufacturing a TRSV with this radial bore requires several high-precision drilling and thread tapping operations in a difficult-to-machine material. Any mistake in the cutting of these features necessitates that the entire upper subassembly of the TRSV be scrapped. The manufacturing of the radial bore also adds considerable expense to the TRSV, while at the same time reducing the overall reliability of the finished product. Additionally, these added expenses add complexity that must be built into every installed TRSV, while it will only be put to use in some small fraction thereof.
[0010] Attempts have been made to overcome these problems. For example, attempts have been made to communicate hydraulic control to a WRSV through a TRSV using a radial cutting tool to create a fluid passageway from an annular hydraulic chamber in the TRSV to the interior of the TRSV such that hydraulic control may be communicated to the insert WRSV. It has been found, however, that such radial cutting tools are not suitable for creating a fluid passageway from the non annular hydraulic chamber of a rod piston operated TRSVs.
[0011] Therefore, a need has arisen for an apparatus and method for establishing a communication path for hydraulic fluid to a WRSV from a failed rod piston operated TRSV. A need has also arisen for such an apparatus and method that do not require a built-in lock out sleeve in the rod piston operated TRSV. Further, a need has arisen for such an apparatus and method that do not require the rod piston operated TRSV to have a pre-machined radial bore that creates the potential for formation fluids to travel up through the hydraulic control line.
SUMMARY OF THE INVENTION
[0012] The present invention disclosed herein comprises an apparatus and method for establishing a communication path for hydraulic fluid to a wireline retrievable safety valve from a rod piston operated tubing retrievable safety valve. The apparatus and method of the present invention do not require a built-in lock out sleeve in the rod piston operated tubing retrievable safety valve. Likewise, the apparatus and method of the present invention avoid the potential for formation fluids to travel up through the hydraulic control line associated with a pre-drilled radial bore in the tubing retrievable safety valve.
[0013] In broad terms, the apparatus of the present invention allows hydraulic control to be communicated from a non annular hydraulic chamber of a rod piston operated tubing retrievable safety valve to the interior thereof so that the hydraulic fluid may, for example, be used to operate a wireline retrievable safety valve. This may become necessary when a malfunction of the rod piston operated tubing retrievable safety valve is detected and a need exists to otherwise achieve the functionality of the rod piston operated tubing retrievable safety valve.
[0014] The rod piston operated tubing retrievable safety valve of the present invention has a housing having a longitudinal bore extending therethrough. The safety valve also has a non annular hydraulic chamber in a sidewall portion thereof. A valve closure member is mounted in the housing to control fluid flow through the longitudinal bore by operating between closed and opened positions. A flow tube is disposed within the housing and is used to shift the valve closure member between the closed and opened positions. A rod piston, which is slidably disposed in the non annular hydraulic chamber of the housing, is operably coupled to the flow tube. The safety valve of the present invention also has a pocket in the longitudinal bore.
[0015] In one embodiment of the present invention a communication tool is used to establish a communication path between the non annular hydraulic chamber in a sidewall portion of the safety valve and the interior of the safety valve. In this embodiment, the communication tool has a first section and a second section that are initially coupled together using a shear pin or other suitable coupling device. A set of axial locating keys is operably attached to the first section of the tool and is engagably positionable within a profile of the safety valve. The tool includes a radial cutting device that is radially extendable through a window of the second section. For example, the radial cutting device may include a carrier having an insert removably attached thereto and a punch rod slidably operable relative to the carrier to radially outwardly extend the insert exteriorly of the second section.
[0016] The tool also includes a circumferential locating key that is operably attached to the second section of the tool. The circumferential locating key is engagably positionable within the pocket of the safety valve. Specifically, when the first and second sections of the tool are decoupled, the second section rotations relative to the first section until the circumferential locating key engages the pocket, thereby circumferentially aligning the radial cutting device with the non annular hydraulic chamber. A torsional biasing device such as a spiral wound torsion spring places a torsional load between the first and second sections such that when the first and second sections are decoupled, the second section rotates relative to the first section. A collet spring may be used to radially outwardly bias the circumferential locating key such that the circumferential locating key will engage the pocket, thereby stopping the rotation of the second section relative to the first section. Once the circumferential locating key has engaged the pocket, the radial cutting device will be axially and circumferentially aligned with the non annular hydraulic chamber. Through operation of the radial cutting device, a communication path is created from the non annular hydraulic fluid chamber to the interior of the safety valve.
[0017] As such, hydraulic fluid may now be communicated down the existing hydraulic lines to the interior of the tubing. Once this communication path exists, for example, a wireline retrievable safety valve may be positioned within the rod piston operated tubing retrievable safety valve such that the hydraulic fluid pressure from the hydraulic system may be communicated to a wireline retrievable safety valve.
[0018] In another embodiment of the present invention, a lock out and communication tool is used to lock out the safety valve and then establish a communication path between the non annular hydraulic chamber in a sidewall portion of the safety valve and the interior of the safety valve. In this embodiment, the lock out and communication tool is lowered into the safety valve until the lock out and communication tool engages the flow tube. The lock out and communication tool may then downwardly shift the flow tube, either alone or in conjunction with an increase in the hydraulic pressure acting on the rod piston, to operate the valve closure member from the closed position to the fully open position. Alternatively, if the safety valve is already in the open position, the lock out and communication tool simply prevents movement of the flow tube to maintain the safety valve in the open position. Thereafter, the lock out and communication tool interacts with the safety valve as described above with reference to the communication tool to communicate hydraulic fluid from the non annular hydraulic fluid chamber to the interior of the safety valve.
[0019] One method of the present invention that utilizes the communication tool involves inserting the communication tool into the safety valve, locking the communication tool within the safety valve with the safety valve in a valve open position, axially aligning the radially cutting device with the non annular hydraulic chamber, circumferentially aligning the radially cutting device with the non annular hydraulic chamber and penetrating the radially cutting device through the sidewall portion and into the non annular hydraulic chamber to create a communication path between the non annular hydraulic chamber and the interior of the safety valve.
[0020] In addition, a method of the present invention that utilizes the lock out and communication tool involves engaging the flow tube of the safety valve with the lock out and communication tool, retrieving the lock out and communication tool from the safety valve and maintaining the safety valve in the valve open position by preventing movement of the rod piston with an insert that is left in place within the sidewall portion when the remainder of the radial cutting tool is retracted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a more complete understanding of the present invention, including its features and advantages, reference is now made to the detailed description of the invention, taken in conjunction with the accompanying drawings in which like numerals identify like parts and in which:
[0022] FIG. 1 is a schematic illustration of an offshore production platform wherein a wireline retrievable safety valve is being lowered into a tubing retrievable safety valve to take over the functionality thereof;
[0023] FIGS. 2A-2B are cross sectional views of successive axial sections of a rod piston operated tubing retrievable safety valve of the present invention in its valve closed position;
[0024] FIGS. 3A-3B are cross sectional views of successive axial sections of a rod piston operated tubing retrievable safety valve of the present invention in its valve open position;
[0025] FIGS. 4A-4B are cross sectional views of successive axial sections of a communication tool of the present invention;
[0026] FIGS. 5A-5B are cross sectional views of successive axial sections of a communication tool of the present invention in its running position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0027] FIGS. 6A-6B are cross sectional views of successive axial sections of a communication tool of the present invention in its locked position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0028] FIGS. 7A-7B are cross sectional views of successive axial sections of a communication tool of the present invention in its orienting position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0029] FIGS. 8A-8B are cross sectional views of successive axial sections of a communication tool of the present invention in its perforating position and disposed in a rod piston operated tubing retrievable safety valve of the present invention;
[0030] FIGS. 9A-9B are cross sectional views of successive axial sections of a communication tool of the present invention in its retrieving position and still substantially disposed in a rod piston operated tubing retrievable safety valve of the present invention; and
[0031] FIGS. 10A-10C are cross sectional views of successive axial sections of a lock out and communication tool of the present invention disposed in a rod piston operated tubing retrievable safety valve of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.
[0033] Referring to FIG. 1 , an offshore oil and gas production platform having a wireline retrievable safety valve lowered into a tubing retrievable safety valve is schematically illustrated and generally designated 10 . A semi-submersible platform 12 is centered over a submerged oil and gas formation 14 located below sea floor 16 . Wellhead 18 is located on deck 20 of platform 12 . Well 22 extends through the sea 24 and penetrates the various earth strata including formation 14 to form wellbore 26 . Disposed within wellbore 26 is casing 28 . Disposed within casing 28 and extending from wellhead 18 is production tubing 30 . A pair of seal assemblies 32 , 34 provide a seal between tubing 30 and casing 28 to prevent the flow of production fluids therebetween. During production, formation fluids enter wellbore 26 through perforations 36 in casing 28 and travel into tubing 30 to wellhead 18 .
[0034] Coupled within tubing 30 is a tubing retrievable safety valve 38 . As is well known in the art, multiple tubing retrievable safety valves are commonly installed as part of tubing string 30 to shut in production from formation 14 in response to a variety of abnormal and potentially dangerous conditions. For convenience of illustration, however, only tubing retrievable safety valve 38 is shown.
[0035] Tubing retrievable safety valve 38 is operated by hydraulic fluid pressure communicated thereto from surface installation 40 and hydraulic fluid control conduit 42 . Hydraulic fluid pressure must be applied to tubing retrievable safety valve 38 to place tubing retrievable safety valve 38 in the open position. When hydraulic fluid pressure is lost, tubing retrievable safety valve 38 will operate to the closed position to prevent formation fluids from traveling therethrough.
[0036] If, for example, tubing retrievable safety valve 38 is unable to properly seal in the closed position or does not properly open after being in the closed position, tubing retrievable safety valve 38 must typically be repaired or replaced. In the present invention, however, the functionality of tubing retrievable safety valve 38 may be replaced by wireline retrievable safety valve 44 , which may be installed within tubing retrievable safety valve 38 via wireline assembly 46 including wireline 48 . Once in place within tubing retrievable safety valve 38 , wireline retrievable safety valve 44 will be operated by hydraulic fluid pressure communicated thereto from surface installation 40 and hydraulic fluid line 42 through tubing retrievable safety valve 38 . As with the original configuration of tubing retrievable safety valve 38 , the hydraulic fluid pressure must be applied to wireline retrievable safety valve 44 to place wireline retrievable safety valve 44 in the open position. If hydraulic fluid pressure is lost, wireline retrievable safety valve 44 will operate to the closed position to prevent formation fluids from traveling therethrough.
[0037] Even though FIG. 1 depicts a cased vertical well, it should be noted by one skilled in the art that the present invention is equally well-suited for uncased wells, deviated wells or horizontal wells. Also, even though FIG. 1 depicts an offshore operation, it should be noted by one skilled in the art that the present invention is equally well-suited for use in onshore operations.
[0038] Referring now to FIGS. 2A and 2B , therein is depicted cross sectional views of successive axial sections a tubing retrievable safety valve embodying principles of the present invention that is representatively illustrated and generally designated 50 . Safety valve 50 may be connected directly in series with production tubing 30 of FIG. 1 . Safety valve 50 has a substantially cylindrical outer housing 52 that includes top connector subassembly 54 , intermediate housing subassembly 56 and bottom connector subassembly 58 which are threadedly and sealing coupled together.
[0039] It should be apparent to those skilled in the art that the use of directional terms such as top, bottom, above, below, upper, lower, upward, downward, etc. are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. As such, it is to be understood that the downhole components described herein may be operated in vertical, horizontal, inverted or inclined orientations without deviating from the principles of the present invention.
[0040] Top connector subassembly 54 includes a substantially cylindrical longitudinal bore 60 that serves as a hydraulic fluid chamber. Top connector subassembly 54 also includes a profile 62 and a radially reduced area 64 . In accordance with an important aspect of the present invention, top connector subassembly 54 has a pocket 66 . In the illustrated embodiment, the center of pocket 66 is circumferentially displaced 180 degrees from longitudinal bore 60 . It will become apparent to those skilled in the art that pocket 66 could alternatively be displaced circumferentially from longitudinal bore 60 at many other angles. Likewise, it will become apparent to those skilled in the art that more than one pocket 66 could be used. In that configuration, the multiple pockets 66 could be displaced axially from one another along the interior surface of top connector subassembly 54 .
[0041] Hydraulic control pressure is communicated to longitudinal bore 60 of safety valve 50 via control conduit 42 of FIG. 1 . A rod piston 68 is received in slidable, sealed engagement against longitudinal bore 60 . Rod piston 68 is connected to a flow tube adapter 70 which is threadedly connected to a flow tube 72 . Flow tube 72 has profile 74 and a downwardly facing annular shoulder 76 .
[0042] A flapper plate 78 is pivotally mounted onto a hinge subassembly 80 which is disposed within intermediate housing subassembly 56 . A valve seat 82 is defined within hinge subassembly 80 . It should be understood by those skilled in the art that while the illustrated embodiment depicts flapper plate 78 as the valve closure mechanism of safety valve 50 , other types of safety valves including those having different types of valve closure mechanisms may be used without departing from the principles of the present invention, such valve closure mechanisms including, but not limited to, rotating balls, reciprocating poppets and the like.
[0043] In normal operation, flapper plate 78 pivots about pivot pin 84 and is biased to the valve closed position by a spring (not pictured). When safety valve 50 must be operated from the valve closed position, depicted in FIGS. 2A-2B , to the valve opened position, depicted in FIGS. 3A-3B , hydraulic fluid enters longitudinal bore 60 and acts on rod piston 68 . As the downward hydraulic force against rod piston 68 exceeds the upward bias force of spiral wound compression spring 86 , flow tube 72 moves downwardly with rod piston 68 . As flow tube 72 continues to move downwardly, flow tube 72 contacts flapper closure plate 78 and forces flapper closure plate 78 to the open position.
[0044] When safety valve 50 must be operated from the valve open position to the valve closed position, hydraulic pressure is released from conduit 42 such that spring 86 acts on shoulder 76 and upwardly bias flow tube 72 . As flow tube 72 is retracted, flapper closure plate 78 will rotate about pin 84 and seal on seat 82 .
[0045] If safety valve 50 becomes unable to properly seal in the closed position or does not properly open after being in the closed position, it is desirable to reestablish the functionality of safety valve 50 without removal of tubing 30 . In the present invention this is achieved by inserting a lock out and communication tool into the central bore of safety valve 50 .
[0046] Referring now to FIGS. 4A-4B , therein is depicted cross sectional views of successive axial sections a lock out and communication tool embodying principles of the present invention that is representatively illustrated and generally designated 100 . Communication tool 100 has an outer housing 102 . Outer housing 102 has an upper subassembly 104 that has a radially reduced interior section 106 . Outer housing 102 also has a key retainer subassembly 108 including windows 110 and a set of axial locating keys 112 . In addition, outer housing 102 has a lower housing subassembly 114 .
[0047] Slidably disposed within outer housing 102 is upper mandrel 116 that is securably coupled to expander mandrel 118 by attachment members 120 . Upper mandrel 116 carries a plurality of dogs 122 . Partially disposed and slidably received within upper mandrel 116 is a fish neck 124 including a fish neck mandrel 126 and a fish neck mandrel extension 128 . Partially disposed and slidably received within fish neck mandrel 126 and fish neck mandrel extension 128 is a punch rod 130 . Punch rod 130 extends down through communication tool 100 and is partially disposed and selectively slidably received within main mandrel 132 .
[0048] Punch rod 130 and main mandrel 132 are initially fixed relative to one another by shear pin 134 . Main mandrel 132 is also initially fixed relative to lower housing subassembly 114 of outer housing 102 by shear pins 136 . Shear pins 136 not only prevent relative axial movement between main mandrel 132 and lower housing subassembly 114 but also prevent relative rotation between main mandrel 132 and lower housing subassembly 114 . A torsional load is initially carried between main mandrel 132 and lower housing subassembly 114 . This torsional load is created by spiral wound torsion spring 138 .
[0049] Attached to main mandrel 132 is a circumferential locating key 140 on the upper end of collet spring 142 . Circumferential locating key 140 includes a retaining pin 144 that limits the outward radial movement of circumferential locating key 140 from main mandrel 132 . Disposed within main mandrel 132 is a carrier 146 that has an insert 148 on the outer surface thereof. Insert 148 includes an internal fluid passageway 150 . Carrier 146 and insert 148 are radially extendable through window 152 of main mandrel 132 . Main mandrel 132 has a downwardly facing annual shoulder 154 .
[0050] The operation of communication tool 100 of the present invention will now be described relative to safety valve 50 of the present invention with reference to FIGS. 5A-5B , 6 A- 6 B, 7 A- 7 B, 8 A- 8 B and 9 A- 9 B. In FIGS. 5A-5B , communication tool 100 is in its running configuration. Communication tool 100 is positioned within the longitudinal central bore of safety valve 50 . As communication tool 100 is lowered into safety valve 50 , downwardly facing annular shoulder 154 of main mandrel 132 contacts profile 74 of flow tube 72 . Main mandrel 132 may downwardly shift flow tube 72 , either alone or in conjunction with an increase in the hydraulic pressure within longitudinal chamber 60 , operating flapper closure plate 78 from the closed position, see FIGS. 2A-2B , to the fully open position, see FIGS. 3A-3B . Alternatively, if safety valve 50 is already in the open position, main mandrel 132 simply holds flow tube 72 in the downward position to maintain safety valve 50 in the open position. Communication tool 100 moves downwardly relative to outer housing 52 of safety valve 50 until axial locating keys 112 of communication tool 100 engage profile 62 of safety valve 50 .
[0051] Once axial locating keys 112 of communication tool 100 engage profile 62 of safety valve 50 , downward jarring on communication tool 100 shifts fish neck 124 along with fish neck mandrel 126 , fish neck mandrel extension 128 , upper mandrel 116 and expander mandrel 118 downwardly relative to safety mandrel 50 and punch rod 130 . This downward movement shifts expander mandrel 118 behind axial locating keys 112 which locks axial locating keys 112 into profile 62 , as best seen in FIGS. 6A-6B .
[0052] In this locked configuration of communication tool 100 , dogs 122 are aligned with radially reduced interior section 106 of upper housing subassembly 104 . As such, additional downward jarring on communication tool 100 outwardly shifts dogs 122 which allows fish neck mandrel extension 128 to move downwardly. This allows the lower surface of fish neck 124 to contact the upper surface of punch rod 130 . Continued downward jarring with a sufficient and predetermined force shears pins 136 , as best seen in FIGS. 7 A- 7 B. When pins 136 shear, this allows punch rod 130 and main mandrel 132 to move axially downwardly relative to housing 102 and expander mandrel 118 of communication tool 100 and safety valve 50 . This downward movement axially aligns carrier 146 and insert 148 with radially reduced area 64 and axially aligns circumferential locating key 140 with pocket 66 of safety valve 50 .
[0053] In addition, when pins 136 shear, this allows punch rod 130 and main mandrel 132 to rotate relative to housing 102 and expander mandrel 118 of communication tool 100 and safety valve 50 due to the torsional force stored in torsion spring 138 . This rotational movement circumferentially aligns carrier 146 and insert 148 with longitudinal bore 60 of safety valve 50 . This is achieved due to the interaction of circumferential locating key 140 and pocket 66 . Specifically, as punch rod 130 and main mandrel 132 rotate relative to safety valve 50 , collet spring 142 radially outwardly biases circumferential locating key 140 . Thus, when circumferential locating key 140 becomes circumferentially aligned with pocket 66 , circumferential locating key 140 moves radially outwardly into pocket 66 stopping the rotation of punch rod 130 and main mandrel 132 relative to safety valve 50 . By axially and circumferentially aligning circumferential locating key 140 with pocket 66 , carrier 146 and insert 148 become axially and circumferentially aligned with longitudinal bore 60 of safety valve 50 .
[0054] Once carrier 146 and insert 148 are axially and circumferentially aligned with longitudinal bore 60 of safety valve 50 , communication tool 100 is in its perforating position, as depicted in FIGS. 8A-8B . In this configuration, additional downward jarring on communication tool 100 , of a sufficient and predetermined force, shears pin 134 which allow punch rod 130 to move downwardly relative to main mandrel 132 . As punch rod 130 move downwardly, insert 148 penetrates radially reduced region 64 of safety valve 50 . The depth of entry of insert 148 into radially reduced region 64 is determined by the number of jars applied to punch rod 130 . The number of jars applied to punch rod 130 is predetermined based upon factors such as the thickness of radially reduced region 64 and the type of material selected for outer housing 52 .
[0055] With the use of communication tool 100 of the present invention, fluid passageway 150 of insert 148 provides a communication path for hydraulic fluid from longitudinal bore 60 to the interior of safety valve 50 . Once insert 148 is fixed within radially reduced region 64 , communication tool 100 may be retrieved to the surface, as depicted in FIGS. 9A-9B . In this configuration, punch rod 130 has retracted from behind carrier 146 , fish neck mandrel extension 128 has retracted from behind keys 106 and expander mandrel 118 has retracted from behind axial locating keys 112 which allows communication tool 100 to release from safety valve 50 . Insert 148 now prevents the upward movement of rod piston 68 and flow tube 72 which in turn prevents closure of flapper closure plate 78 , thereby locking out safety valve 50 . In addition, flow passageway 150 of insert 148 allow for the communication of hydraulic fluid from longitudinal bore 60 to the interior of safety valve 50 which can be used, for example, to operate a wireline retrievable subsurface safety valve that is inserted into locked out safety valve 50 .
[0056] Referring now to FIGS. 10A-10C , therein is depicted cross sectional views of successive axial sections a lock out and communication tool embodying principles of the present invention that is representatively illustrated and generally designated 200 . The communication tool portion of lock out and communication tool 200 has an outer housing 202 . Outer housing 202 has an upper subassembly 204 that has a radially reduced interior section 206 . Outer housing 202 also has a key retainer subassembly 208 including windows 210 and a set of axial locating keys 212 . In addition, outer housing 202 has a lower housing subassembly 214 .
[0057] Slidably disposed within outer housing 202 is upper mandrel 216 that is securably coupled to expander mandrel 218 by attachment members 220 . Upper mandrel 216 carries a plurality of dogs 222 . Partially disposed and slidably received within upper mandrel 216 is a fish neck 224 including a fish neck mandrel 226 and a fish neck mandrel extension 228 . Partially disposed and slidably received within fish neck mandrel 226 and fish neck mandrel extension 228 is a punch rod 230 . Punch rod 230 extends down through lock out and communication tool 200 and is partially disposed and selectively slidably received within main mandrel 232 and main mandrel extension 260 of the lock out portion of lock out and communication tool 200 .
[0058] Punch rod 230 and main mandrel 232 are initially fixed relative to one another by shear pin 234 . Main mandrel 232 is also initially fixed relative to lower housing subassembly 214 of outer housing 202 by shear pins 236 . Shear pins 236 not only prevent relative axial movement between main mandrel 232 and lower housing subassembly 214 but also prevent relative rotation between main mandrel 232 and lower housing subassembly 214 . A torsional load is initially carried between main mandrel 232 and lower housing subassembly 214 . This torsional load is created by spiral wound torsion spring 238 .
[0059] Attached to main mandrel 232 is a circumferential locating key 240 on the upper end of collet spring 242 . Circumferential locating key 240 includes a retaining pin 244 that limits the outward radial movement of circumferential locating key 240 from main mandrel 232 . Disposed within main mandrel 232 is a carrier 246 that has an insert 248 on the outer surface thereof. Insert 248 includes an internal fluid passageway 250 . Carrier 246 and insert 248 are radially extendable through window 222 of main mandrel 232 . Main mandrel 232 is threadedly attached to main mandrel extension 260 . In the illustrated embodiment, the lock out portion of lock out and communication tool 200 also includes a lug 262 with contacts upper shoulder 74 , a telescoping section 264 and a ratchet section 266 . In addition, a piston the lock out portion of lock out and communication tool 200 includes a dimpling member 268 that is radially extendable through a window 270 .
[0060] In operation, as lock out and communication tool 200 is positioned within the longitudinal central bore of safety valve 50 as described above with reference to tool 100 , flapper closure plate 78 is operated from the closed position, see FIGS. 2A-2B , to the fully open position, see FIGS. 3A-3B . Lock out and communication tool 200 moves downwardly relative to outer housing 52 of safety valve 50 until axial locating keys 212 of lock out and communication tool 200 engage profile 62 of safety valve 50 and are locked therein.
[0061] In this locked configuration of lock out and communication tool 200 , shears pins 236 may be sheared in response to downward jarring which allows punch rod 230 and main mandrel 232 to move axially downwardly relative to housing 202 and expander mandrel 218 of lock out and communication tool 200 and safety valve 50 . As explained above, this downward movement axially aligns carrier 246 and insert 248 with radially reduced area 64 . In addition, circumferential locating key 240 is both axially and circumferentially aligned with pocket 66 of safety valve 50 .
[0062] By axially and circumferentially aligning circumferential locating key 240 with pocket 66 , carrier 246 and insert 248 become axially and circumferentially aligned with longitudinal bore 60 of safety valve 50 such that additional downward jarring on lock out and communication tool 200 of a sufficient and predetermined force shears pin 234 which allow punch rod 230 to move downwardly relative to main mandrel 232 and main mandrel extension 260 . As punch rod 230 move downwardly, insert 248 penetrates radially reduced region 64 of safety valve 50 . Further travel of punch rod 230 downwardly relative to main mandrel 232 and main mandrel extension 260 causes dimpling member 268 to contact and form a dimple in the inner wall of safety valve 50 which prevents upward travel of piston 68 after lock out and communication tool 200 is retrieved from safety valve 50 .
[0063] The unique interaction of lock out and communication tool 200 of the present invention with safety valve 50 of the present invention thus allows for the locking out of a rod piston operated safety valve and for the communication of its hydraulic fluid to operate, for example, an insert valve.
[0064] While this invention has been described with a reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
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A tubing retrievable safety valve ( 50 ) having a non annular hydraulic chamber ( 60 ) in a sidewall portion thereof is operable to received a communication tool ( 100 ) therein such that relative rotation between at least a portion of the communication tool ( 100 ) and the tubing retrievable safety valve ( 50 ) is substantially prevented. The communication tool ( 100 ) is operable to create a fluid passageway ( 150 ) between the non annular hydraulic chamber ( 60 ) and the interior of the tubing retrievable safety valve ( 50 ) by penetrating through the sidewall portion and into the non annular hydraulic chamber ( 60 ). Thereafter, when a wireline retrievable safety valve ( 44 ) is positioned within the tubing retrievable safety valve ( 50 ), hydraulic fluid is communicatable thereto through the fluid passageway ( 150 ).
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DEAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
This invention relates to novel organosilicon compounds and a method for their preparation. More particularly, this invention relates to novel organosilicon compounds that carry a silicon-bonded organofunctional group at both molecular chain terminals while bearing SiH in terminal position on a side chain branching from the main chain. The invention also relates to a method for the preparation of the described novel organosilicon compounds.
2. Background of the Invention
Organofunctionalized organopolysiloxanes are used to impart the desirable properties characteristic of organosiloxanes to conventional organic resins, such as water repellency, release properties, waterproofness, lubricity, weathering resistance, heat resistance, selective gas permeability, inter alia. There have recently been a number of reports on heteropolyfunctional silicone compounds that are regarded as well-adapted for the modification or improvement of organic resins. When silicone compounds of this type are used to modify organic resins, the functional groups remaining in the resulting silicone-modified organic resin can be exploited for subsequent crosslinking and curing reactions. For example, Japanese Patent Application Laid Open Number Hei 6-80779 discloses a difunctional silicone compound that contains silicon-bonded hydrogen and the dicarboxylic anhydride group in the same molecule. In this case, the dicarboxylic anhydride group can be used for the modification of polyimide resin and the Si-bonded hydrogen remaining in the modified resin is available for crosslinking reactions. Japanese Patent Application Laid Open Number Hei 6-80783 discloses a silicone-modified polyimide resin that possesses a plurality of silicon-bonded hydrogen at the terminals of the polymer main chain.
There are also disclosed in Polymer Preprints, Japan, Volume 42, pp. 486, 487, 1496 (1993) a silicone compound that can introduce SiH into the polymer main chain and a silicone compound bearing both SiH and polycarboxylic anhydride moieties. The latter compound is synthesized by Grignard and Dieis-Alder reactions.
With respect to the aforementioned heteropolyfunctional silicone compounds, however, the SiH is introduced in each case at the terminals of the polymer main chain, which necessarily restricts the SiH content to a very limited range. While introduction of SiH into the polymer main chain is desirable in order to broaden the range from which the SiH content can be selected, the synthesis of the corresponding silicone compounds has required the use of organometals and has proceeded through a multistep process that includes a by-product-rich Grignard reaction. As a result, there is a need for novel heteropolyfunctional silicone compounds that are well-suited for the modification of organic resins. The introduction of a simple method for the preparation of these compounds is also desired.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide novel heteropolyfunctional silicone compounds that bear organofunctional groups at both terminals and carry siliconbonded hydrogen in the main chain. Another object of the present invention is to provide a method for the preparation of these novel heteropolyfunctional silicone compounds.
The present invention relates to organosilicon compounds with the general formula ##STR1## wherein each R 1 is independently selected from C 1 to C 20 monovalent hydrocarbon groups that are free of aliphatic unsaturation; R 2 represents a C 1 to C 20 divalent organic group; A is a group selected from amino-functional organic groups, epoxy-functional organic groups, hydroxyl group or a group obtained by substituting active hydrogen in the preceding groups with triorganosilyl; a is an integer from 1 to 20; b is an integer from 1 to 20; c is an integer from 0 to 20; and d is an integer from 1 to 20.
The invention also relates to a method for the preparation of the above organosilicon compounds wherein said method is characterized by the addition reaction, in the presence of a platinum catalyst, between
(A) an organosilicon compound with the general formula ##STR2## wherein each R 1 is independently selected from C 1 to C 20 monovalent hydrocarbon groups that are free of aliphatic unsaturation, a is an integer from 1 to 20, b is an integer from to 20, c is an integer from 0 to 20, and d is an integer from 1 to 20 and
(B) an aliphatically unsaturated organic compound containing a group selected from amino-functional organic groups, epoxy-functional organic groups, hydroxyl group or an aliphatically unsaturated organic compound as obtained by substituting active hydrogen in the aforesaid groups with triorganosilyl.
The present invention has been disclosed in Japanese Patent Application Number Hei 07/157176, the full disclosure of which is hereby incorporated by reference.
DETAILED DESCRIPTION OF THE INVENTION
Organosilicon compounds according to the present invention are defined by the formula ##STR3## Each R 1 in this formula is independently selected from C 1 to C 20 monovalent hydrocarbon groups that are free of aliphatic unsaturation. R 1 is specifically exemplified by alkyl groups such as methyl, ethyl, propyl, butyl, and so forth; aryl groups such as phenyl, tolyl, xylyl, and so forth; and substituted alkyl groups such as chloromethyl, perfluoromethyl, and so forth. Considerations such as cost and availability of starting materials make it desirable for methyl to constitute at least 80% of the subject monovalent hydrocarbon groups. R 2 represents C 1 to C 20 divalent organic groups and is specifically, but nonexhaustively, exemplified by alkylene groups such as methylene, ethylene, propylene, butylene, and so forth, and by arylene groups such as phenylene, tolylene, xylylene, and so forth. A is a group selected from amino-functional organic groups, epoxy- functional organic groups, hydroxyl group or a group obtained by substituting at least one active hydrogen in any one of the preceding groups with triorganosilyl. The following groups are examples of organofunctional groups in which group A is bonded with R 2
H 2 NC 3 H 6 --
CH 3 NHC 3 H 6 --
CH 3 NHC 4 H 8 ---
(CH 3 ) 3 SiNHC 3 H 6 -- ##STR4## (CH 3 ) 3 SiOC 2 H 4 OC 3 H 6 --H 2 NC 2 H 4 NHC 3 H 6 --
The subscripts a and b in the preceding general formula (i) are both integers from 1 to 20 and preferably from 1 to 5. The subscript c is an integer from 0 to 20 and preferably from 0 to 3, and the subscript d is an integer from 1 to 20 and preferably from 1 to 5.
The subject organosilicon compounds of formula (i) are specifically exemplified by the following ##STR5##
The method according to the present invention for the preparation of the above-described organosilicon compounds according to formula (i) will now be considered.
The organosilicon compound (A) used by the preparative method according to the present invention is defined by the following formula. ##STR6## wherein R 1 , a, b and c are as defined above. The organosilicon compound (A) is specifically exemplified by compounds with the following formulas ##STR7##
The compound (B) used in the preparative method according to the present invention is an aliphatically unsaturated organic compound containing a group selected from amino-functional organic groups, epoxy-functional organic groups, hydroxyl group or an aliphatically unsaturated organic compound obtained by substituting triorganosilyl for active hydrogen in the aforesaid groups. Compound (B) is specifically exemplified by the following compounds
H 2 NCH 2 CH═CH 2 ,
CH 3 NHCH 2 CH═CH 2 ,
CH 3 NHC 2 H 4 CH═CH 2 ,
(CH 3 ) 3 SiNHCH 2 CH═CH 2 , ##STR8## (CH 3 ) 3 SiOCH 2 CH═CH 2 , (CH 3 ) 3 SiOC 2 H 4 OCH 2 CH═CH 2 AND
H 2 NC 2 H 4 NHCH 2 CH═CH 2
The organosilicon compound (A) and compound (B) are preferably used in the preparative method according to the present invention in quantities that yield a molar ratio in the range defined by the following equation: ##EQU1## When a compound B/organosilicon compound (A) molar ratio of less than about 2 is used, the adduct of only a single molecule of compound (B) to organosilicon compound (A) is obtained. When this molar ratio exceeds about 2.5, large amounts of adduct will be produced in which 3 molecules of compound (B) have added to the organosilicon compound (A). Either case results in a reduced yield of the desired organosilicon compound according to the formula (i).
The catalyst used for the addition reaction between organosilicon compound (A) and compound (B) comprises those catalysts generally used to promote hydrosilylation reactions.
The catalyst is specifically, but nonexhaustively, exemplified by platinum catalysts such as chloroplatinic acid, alcohol solutions of chloroplatinic acid, platinum/olefin complexes, platinum/vinylsiloxane complexes, and the like, as well as by rhodium catalysts such as Wilkinson's complex, rhodium/carbonyl complexes, the like. The catalyst should be used in this addition reaction at a level of about 1 to 100 weight parts as platinum atoms (preferably at from 1 to 50 weight parts as platinum atoms) for each 1,000,000 weight parts of the total amount of organosilicon compound (A) and compound (B). The addition reaction may not develop at less than 1 weight part, while the addition reaction is not accelerated in proportion to the amount used at above about 100 weight parts and the use of large amounts of these expensive catalysts is uneconomical.
The temperature of the addition reaction is not crucial, but will generally fall in the range from about 50° C. to 250° C. and preferably falls in the range from 50° C. to 200° C. Reaction temperatures below about 50° C. result in a slower reaction rate, and hence a diminished productivity. Reaction temperatures in excess of about 250° C. cause the occurrence of undesirable secondary reactions, such as, the production of adduct in which 3 molecules of compound (B) have added to the organosilicon compound (A).
Organic solvent may be used on an optional basis in the addition reaction under consideration as long as the objects of the invention remain unimpaired. Operable organic solvents are exemplified by toluene, xylene, hexane, heptane, tetrahydrofuran, 1,4 - dioxane, and the like.
After completion of the addition reaction, the organosilicon product can be recovered by distillation from the reaction mixture. Alternatively, the product may be obtained by eliminating the low-boiling components from the reaction mixture by distillation at reduced pressure.
Organosilicon compounds according to the present invention are useful as modifiers or improvers for various types of organic resins. Organic resins modified or improved by the subject organosilicon compounds exhibit such properties as a highly durable adherence for a variety of substrates, an improved moisture resistance, and so forth.
EXAMPLES
The invention will be more specifically explained in the following with reference to working examples.
Example 1
An organosilicon compound (164.1 g) with the following formula was introduced under nitrogen into a four-neck flask equipped with stirrer, reflux condenser, addition funnel, and thermometer ##STR9## The flask was stirred and heated, and when the liquid temperature reached 90° C., 14 mg of chloroplatinic acid/1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (platinum atom concentration=5 weight%) was introduced. N-trimethylsilylallylamine (175.2 g) was then added dropwise over a period of 3.5 hours, during which time the reaction temperature rose to 175° C. During this addition, more of the above described platinum-vinylsiloxane complex was added as appropriate to ultimately bring its total to 49 mg. Stirring was continued for 30 minutes after the completion of addition and this was followed by cooling to room temperature.
Anhydrous methanol (44.9 g) was added dropwise over a period of 23 minutes, during which time the reaction temperature varied from 27° C. to 48° C. After the completion, of addition stirring was continued for 46 minutes at 43° C to 48° C. After cooling to room temperature, a Vigreux fractionation column was installed and distillation was carried out to yield 147.9 g (yield=63%) of an organosilicon compound with the following formula as the fraction at 168° C./10 mmHg-186° C./10 mmHg. ##STR10##
Example 2
An organosilicon compound (37.6 g) with the following formula was introduced under nitrogen into a four-neck flask equipped with stirrer, reflux condenser, addition funnel, and thermometer ##STR11## The flask was stirred and heated, and when the liquid temperature reached 110° C., 14 mg of chloroplatinic acid/1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (platinum atom concentration=5 weight%) was introduced. Allyl glycidyl (32.0g) ether was then added dropwise over a period of 1.1 hours, during which time the reaction temperature rose to 203° C. Stirring was continued for 43 minutes after the completion of addition and this was followed by cooling to room temperature. A Vigreux fractionation column was then installed and distillation was carried out to yield 49.4 g (yield=71%) organosilicon compound with the following formula as the fraction at 170° C./2 mmHg-178° C./2 mmHg ##STR12##
Example 3
An organosilicon compound (26.9 g) with the following formula was introduced under nitrogen into a four-neck flask equipped with stirrer, reflux condenser, addition funnel, and thermometer ##STR13##
The flask was stirred and heated, and when the liquid temperature reached 95° C., 14 mg of chloroplatinic acid/1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (platinum atom concentration=5 weight%) was introduced. Trimethylsilyl allyl ether (26.1g) was then added dropwise over a period of 1.7 hours, during which time the reaction temperature rose to 167° C. Stirring was continued for 55 minutes after the completion of addition and this was followed by cooling to room temperature. A Vigreux fractionation column was then installed and distillation was carried out to yield 39.7 g (yield=75%) organosilicon compound with the following formula as the fraction at 143° C./2 mmHg-146° C./2 mmHg ##STR14##
Application Example
While operating under nitrogen, 6.3 g of pyromellitic dianhydride and 34.8 g of a mixture of N,N-dimethylacetamide and xylene (mixing ratio=95:5 by weight) were introduced into a flask equipped with stirrer, addition funnel, and thermometer and were stirred. The addition funnel was charged with 11.1 g of the organosilicon compound prepared in Example 1 and 34.8 g of a mixture of N,N-dimethylacetamide and xylene (mixing ratio=9:5 by weight). This diaminosiloxane solution was added dropwise from the addition funnel over a period of 29 minutes, during which time the reaction temperature varied from 29° C. to 37° C. This was followed by stirring for 3.5 hours at 37° C. to 26° C. A Dean-Stark receiver was installed and an azeotropic dehydration was run for 8 minutes at 144° C. to 146° C. Cooling to room temperature and filtration yielded 77.3 g of a polyimide solution.
When the infrared absorption spectrum of this solution was measured, the SiH signal at 2130 cm -1 and the imide group signals at 1780 cm -1 and 1720 cm -1 were observed. When this polyimide solution was held for 6 months at room temperature, it remained a homogeneous solution and did not manifest such changes as gel production, precipitate development or viscosity increase.
This polyimide solution was coated on a silicon wafer, glass plate, and aluminum sheet, and in each case a polyimide film was produced by curing for 3 hours in a 160° C. oven. A pressure cooker test was then run for 20 hours at 121° C./100% RH (relative humidity). When a crosshatch adhesion test was conducted on each of these polyimide films, it was found that the polyimide resins adhered well to the various substrates.
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There is disclosed an organosilicon compound which contains a silicon-bonded functional group at each molecular chain terminal as well as a terminal -SiH group on a side chain branching from the main chain, said functional group being selected from amino-functional organic groups, epoxy-functional organic groups, hydroxyl group or a group obtained by substituting active hydrogen in the preceding groups with triorganosilyl group.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application Ser. No. 09/432,248, filed Nov. 2, 1999, now pending, which is a continuation-in-part of application Ser. No. 09/034,562, filed Mar. 3, 1998, now pending, which is a continuation-in-part of application Ser. No. 08/986,378, filed Dec. 8, 1997, now pending, which is a continuation-in-part of application Ser. No. 08/687,082, filed Jul. 23, 1996, now abandoned, which is a continuation-in-part of application Ser. No. 08/521,776, filed Aug. 31, 1995, now abandoned, which is a continuation-in-part of application Ser. No. 08/435,122, filed May 5, 1995, now abandoned.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an improved terminating and grounding strain release clamp assembly, sometimes called a “backshell”, for electrical shielded cables and the like, Prior art such as usage of mechanical band dispersed from a banding tool as the means for joint connection between the “backshell” and terminated electrical cable shields, individual and/or overall, is error-prone, tedious, cumbersome and non-repairable assembly.
[0003] In some known application, such as today's fly-by-wire and/or HIRF configured airplane, an almost absolute minimum amount of EMI presence is critical to the airplane system performance. Simply stated, the electrical cable and/or wire shield grounding shall be continuous and free of contamination. The prior art banding assembly is totally impacted by the assembler disadvantage of not having enough “hands” to locate and position individual and/or overall cable shields while applying the mechanical band and then operating the banding tool. The prior art banding assembly almost consistently produced an unacceptable ground shield terminations such as high resistance, misalignment and improper location of the mechanical band, overlapping cable shield braids, loose mechanical band, etc. Another resultant problem is the susceptibility to environmental contamination. For example, when the cable shield is of nickel plating and the mechanical band is stainless steel and the termination platform on the backshell adapter is cadmuim plated, galvanic action amongst different metals produces corrosion. Another problem associated with the prior art banding assembly is the inherent non-repairable shield termination which increases the airline's cost of ownership.
[0004] The present invention also eliminates the need for a tool and the user friendly assembly significantly improves the EMI performance, greatly reduces assembly cost, increases reliability and allows maintainability.
BRIEF SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to overcome the aforementioned and other deficiencies and disadvantages of the prior art.
[0006] It is another object of the present invention to provide a strain relief adapter female member having a configured inner surface which engages the outer surface of a split compression ring causing a forceful engagement on the compression ring with a backshell adapter male member and the backshell adapter having a slotted termination platform for cable shields.
[0007] A further object of the present invention is to utilize a conductive wrap-around band to collect, position, locate cable shields, individual and overall, onto the termination platform of the backshell adapter.
[0008] A still further object of the present invention is the coupling of the female and male component member to produce an electrical joint connection caused by the split compression ring closing onto the termination platform.
[0009] Yet another object of the invention is to eliminate galvanic action when the assembly has incompatible metals by using a wrap-around band as a barrier between metals.
[0010] It is also an object of the invention to provide a terminating and grounding strain relief clamp assembly which is tool free to assemble, reworkable and maintainable. The present invention provides a terminating and grounding strain release clamp assembly or “backshell” that comprises an interfitting metallic shell, housing and coupling parts such as a split compression ring and a metallic wrap-around band which when all joined together form an electrical conductive path with the cable shields to greatly reduced the presence of electromagnetic interference (EMI).
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0011] [0011]FIG. 1 is a reference view to illustrate current art cable and/or wire shields, individual and overall, preparation.
[0012] [0012]FIG. 2 is an exploded perspective view, made in accordance with the invention, of a terminating and grounding strain release clamp assembly or “backshell” having female and male component members, a split compression ring and wrap-around band and cable shields (as shown in FIG. 1) to be terminated thereto. Also shown is a cold shrinkable sleeving intended for sealing the cable entry area.
[0013] [0013]FIG. 2A is an end portion view of FIG. 2, showing both individual and overall cable shields fittingly enclosed by a wrap-around band at the termination platform of the male component member
[0014] [0014]FIG. 3 is an exploded perspective view illustrating assembly of the terminating and grounding strain release clamp assembly made in accordance with the invention. The cold shrinkable sleeve will provide environmental protection to the assembly.
[0015] [0015]FIG. 4 is a side elevational view of the assembled backshell, a portion thereof being broken away to show the electrical junction formed by the intermitting metallic shell, housing and coupling parts all joined together with the terminated cable shields, individual and overall.
[0016] [0016]FIG. 5 is an isometric view of an airplane connector bonding and grounding system illustrating the joint connection or continuity flow from the cable shield to the backshell to the coupled plug and receptacle connectors to the airplane structure.
DETAILED DESCRIPTION OF THE INVENTION
[0017] An exemplary embodiment of the invention, sometimes called a “backshell”, is shown in FIG. 2 through FIG. 4. The exemplary backshell comprises a generally backshell adapter 1 female component member, a backshell adapter 2 male component member, and a split compression ring 3 and wrap-around band 4 therebetween. For this description, a cold shrinkable sleeving 19 is used for sealing the cable entry area 20 of the strain relief adapter 1 . The male component member 2 includes a slotted end 11 , termination platform 5 and the female component member 1 having a tapered inner periphery or shoulder 6 intended to engaged the outer diameter 7 on the split compression ring 3 . A wrap-around band 4 is provided to collect and positionally maintain terminated individual 9 cable shields on the slotted end 11 of the termination platform 5 . The overall 10 cable shield is then pushed onto the termination platform 5 on the male component member 2 so that it makes an overlap on the individual 9 cable shields as shown in FIG. 2A. Coupling of the female component member 1 to the male component member 2 will cause shoulder 6 to abut on the split compression ring 3 simultaneously with the forceful engagement 13 on the compression ring 3 and the shoulder surface 15 on the termination platform 5 of the backshell adapter 2 male component member. This tightening 14 on the intermediate members brings the compression ring 3 to close its 70°-75° ends 8 to locked 16 onto the termination platform 5 of the male component member 2 as shown in FIGS. 3 and 4. It can be understood that this embodiment joint connection is now a junction which provides electrical continuity from the cable shields 9 , 10 to the backshell. The strain relief adapter 1 female component member is defined by a tapered inner periphery or shoulder 6 behind its internal thread 12 . While the two parts are shown axially separated in FIG. 2, the shoulder 6 will act on the outer diameter 7 of the split compression ring 3 upon coupling of the internal thread 12 in the female component member 1 to the external thread 17 in the male component member 2 .
[0018] The backshell adapter 2 male component member includes a plug housing 19 with external thread 17 and having slotted II termination platform 5 for multiple individual shields 9 and overall shield 10 terminations. The slot 11 controls the location, spacing and positioning of each individual shields 9 on the termination platform 5 . A BeCu wrap-around band 4 is included, more specifically, inserted around the termination platform 5 to collect and maintained location integrity of the assembled cable shields 9 , 10 . Also, on assembly where incompatible metals are to be coupled such as but not limited to, nickel plated overall cable shields 10 and tin plated individual shields 9 to the cadmuim plated termination platform 5 , another piece of the wrap-around band 4 can be used to separate the incompatible metals. In the use of the split compression ring 3 , it is externally formed on the cable 18 of which its configured ends 8 have a 70-75° taper which comes together when under compression. As described earlier, coupling of the strain relief 1 female adapter to the backshell adapter 2 male member forces the split compression ring to close and envelope 16 the termination platform 5 of the backshell adapter 2 . This electrical joint connection is at its level best when the interfitting members are at locations 13 and 14 as shown on FIG. 4.
[0019] As will now be apparent, when the female component member 1 and male component member 2 are connected, without the use of a tool, a joint is formed between the cable shields 9 , 10 and the backshell. Use of a cold shrinkable sleeving 20 to the assembly provides environmental protection at the cable entry area 21 of the strain relief adapter 1 . The present invention provides a terminating and grounding strain release clamp assembly for electrical shielded cable 18 which produces a reliable and maintainable ground connection whose integrity is a result of the user friendly assembly. Another advantage of the invention is the versatility or means to separate incompatible metals which if not eliminated will cause corrosion and degrade the backshell low EMI immunity.
[0020] While the invention has been described with respect to a preferred embodiment, reference to application Ser. Nos. 08/986,378 and 09/034,562 for the parts represented by the legends identified in FIG. 5 may be made to show the present significantly improved, highly reliable and consistent airplane grounding and bonding system which is critical to the functional integrity on a “Fly-by-Wire and High Intensity Radio Frequency (HIRF)” configured airplane. For example and as illustrated in FIG. 5, the shielding continuity from the cable or wire shields is carried on to the present invention backshell while application Ser. No. 09/034,562 provides continuation of the described shielding (electrical joint) onto the mated electrical plug ( 22 ) and receptacle ( 23 ) connectors and application Ser. No. 08/986,378 closes the shield ground loop by extending the electrical joint connection onto the airplane panel and/or structure ( 24 ) with the usage of the projecting grounding wave springs 31 . To further clarify the electrical joint between the mated electrical plug ( 22 ) and receptacle ( 23 ) connectors, it is achieved through the grounding fingers ( 25 ) mounted on the plug ( 22 ) connector. The grounding fingers ( 25 ) can be easily damaged mechanically from severe metal-to-metal interference between grounding fingers ( 25 ) and receptacle ( 23 ) connector metal shell housing and from contamination from aircraft fluids. A new embodiment to ensure reliable joint connection between plug ( 22 ) and receptacle ( 23 ) is the addition of grounding fingers ( 26 ) in a shape of a wave spring on the receptacle ( 23 ) connector. These wave spring grounding fingers ( 26 ) are mounted or located behind the prior art interfacial sealing O-ring ( 27 ) in the receptacle connector therefore eliminating the damage problem discussed on prior art grounding fingers ( 25 ). It can be understood that the wave spring grounding fingers ( 26 ) are depressed or pushed back by plug ( 22 ) and shell face ( 32 ) when plug ( 22 ) and receptacle ( 23 ) are in a mated condition.
[0021] Furthermore, various modifications and improvements may be made to the present embodiments without departing from the scope of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiments, but only by the scope of the appended claims. I claim:
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An EMI terminating and grounding strain release clamp assembly or “backshell” is provided having male and female component members and coupling intermediate members constructed of conductive metals. Upon coupling of the female and male component members a split metallic ring is compressed and envelopes a termination platform with electrical cable shields enclosed in a BeCu wrap-around band. This joint connection produces an electrical grounding path which provides EMI protection. Assembly of the component parts is accomplished without the aid or use of a tool. A sealing member can be used for environmental protection of the backshell interior parts.
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BACKGROUND OF THE INVENTION
[0001] The invention relates to a sensor apparatus for a packaging machine, which is in the form of a capsule filling and closing machine, or for a capsule monitoring apparatus.
[0002] A sensor apparatus such as this is known from DE 10 2005 016 124 A1. The known sensor apparatus is arranged in the area of a capsule filling and closing device and has an X-ray radiation source which passes radiation through containers in the longitudinal direction, which containers are filled with a filling material, for example a pharmaceutical product in the form of powder. A detector is arranged on the side of the container opposite the X-ray radiation source, measures the X-ray radiation after it passes through the container, and supplies this in analog form to an evaluation device. In particular, the weight of the filling material in the containers is determined by means of the sensor apparatus that is so far known.
[0003] This has the disadvantage that, because the containers are arranged in step-like holding holes in holding segments, when the radiation is passed through the containers, their entire cross section is not detected, with a portion of the cross section instead being covered by the holding hole. The result is therefore dependent on the geometry of the holding hole, and the measurement result may be corrupted. Additional statements can be made only with difficulty, if at all, because radiation is passed through the containers in the direction of the longitudinal axis of the containers, since the radiation passes through only a relatively limited area of the container.
[0004] DE 198 19 395 C1, from the same applicant, discloses a weighing device for weighing hard-gelatin capsules, which has a feed element in the form of a flywheel which in each case moves a capsule into the area of a weighing goods holder, which is arranged in a suspended manner, and feeds the capsule on further therefrom.
[0005] U.S. Pat. No. 5,864,600 discloses an image-processing monitoring device, in which the filling level in containers is checked by means of a beam source, with the beam passing through the containers at right angles to their container longitudinal axis. The containers are in this case arranged at a distance from one another on a horizontally arranged feed device.
SUMMARY OF THE INVENTION
[0006] In the light of the described prior art, the invention is based on the object of developing a sensor apparatus for a packaging machine, which is in particular in the form of a monitoring device or a capsule filling and closing device, such that its measurement accuracy is improved, and further conclusions relating to the container and its filling material are made possible in a simple manner. The sensor device is intended to have a high performance and to be to feed and to position the capsules easily in the area of the sensor device. In this case, the invention is based on the idea that, by passing radiation through the container at right angles to its longitudinal axis, this allows radiation to be passed through a greater area of the container, and allows a greater area of the container to be detected, thus allowing a quantitatively and quantitatively better statement to be made about said characteristics. Furthermore, the positioning element, which is tubular or in the form of a shaft and through which the radiation lobe from the beam source can pass makes it possible to position the capsules very easily and at the same time precisely in the area of the sensor device.
[0007] In one preferred embodiment of the invention, an X-ray radiation source is provided as the radiation source. An X-ray radiation source not only makes it possible to detect the filling weight of the container in a simple manner, but also, for example, makes it possible to detect the filling height in the container and damage to the container, or the like.
[0008] Furthermore, in order to improve the performance of the apparatus and to reduce the hardware complexity, the invention particularly preferably provides for a plurality of feed elements to be arranged parallel to one another, and for a plurality of feed elements to be arranged such that they are operatively connected to a common radiation source and to a common detector. A plurality of containers can thus each be checked in one step at the same time, by means of a single radiation source and by means of a single detector.
[0009] One feed option for the containers whose design is simple, in the area of the radiation source, and which at the same time prevents corruption of the measurement results by parts of the apparatus, is achieved in that the containers are arranged stowed in a row in the feed element, and are fed by mutual touching contact of the containers at least in the area of the sensor apparatus.
[0010] It is particularly preferable if the detector is in the form of an image-evaluating detector and interacts with an evaluation device which allows digital data evaluation. This makes it possible to produce various parameters and measurement results from the signals and recordings obtained, in a simple manner.
[0011] In order to achieve accurate measurement, particularly of the weight of a capsule, the invention preferably provides that the at least one radiation source is additionally arranged such that it is operatively connected to a reference object, and that the detector at the same time additionally detects the image of the reference object, in addition to the image of the container, and supplies this to the evaluation device. The image of the container and/or of the capsule is therefore always related to the reference object, thus precluding absolute fluctuations between two successive images, which would lead to corruption of the measurement result.
[0012] In this case, in order to improve the measurement accuracy and to simplify the evaluation, it is particularly advantageous and necessary that the reference object is composed of a material which at least approximately has the same absorption characteristics for the radiation, in particular for the X-ray radiation, as the container.
[0013] In order to ensure that accurate and correct measurement results are achieved over the entire tolerance range of the characteristic to be measured, it is furthermore essential that the reference object has areas of different absorptions for the radiation, with at least one area being provided whose absorption, within the tolerances of the characteristic of the container to be measured, is less than the minimum absorption of the container, and an area whose absorption, within the tolerances of the characteristic of the container (c) to be measured, is greater than the maximum absorption of the container.
[0014] One advantageous refinement, which can be manufactured easily, of the reference object, in which the information relating to the reference object can be processed easily by means of the evaluation device, is made possible if the reference object is in the form of a wedge or step, and if the reference object is arranged such that the thickness of the reference object varies in the radiation direction of the radiation source.
[0015] In a further design refinement of the invention, the sensor device is followed by a weighing device which has at least one weighing cell for weighing the container. A refinement such as this provides a second monitoring option for the containers, as a result of which not only is the X-ray image used for evaluation and/or qualitative or quantitative detection of the container, but also the weighing device. In addition, this allows duplicated monitoring of the filling weight, as a result of which the two measurement results can be compared with one another, and a faulty test device can be deduced if they do not match. The claimed sensor apparatus for a packaging machine therefore operates particularly safely and reliably.
BACKGROUND OF THE INVENTION
[0016] Further advantages will become evident from the following description of preferred exemplary embodiments and from the drawings, in which:
[0017] FIG. 1 shows a simplified plan view of a capsule filling and closing machine,
[0018] FIG. 2 shows a sensor apparatus according to the invention, as used for a packaging machine as shown in FIG. 1 , in the form of a schematic side view and partially sectioned,
[0019] FIG. 3 shows a modified sensor apparatus using holding sections, in which two rows of capsules are in each case fed,
[0020] FIG. 4 shows a simplified front view of the sensor apparatus as shown in FIG. 3 ,
[0021] FIG. 5 shows examples of images recorded by means of an apparatus according to the invention and which are supplied to a digital evaluation device for evaluation,
[0022] FIG. 6 shows a simplified longitudinal section through a monitoring device for capsules,
[0023] FIG. 7 shows a simplified side view of a capsule filling and closing machine which has been modified in comparison to FIGS. 3 and 4 , and
[0024] FIG. 8 shows examples of images which have been recorded by means of the capsule filling and closing machine as shown in FIG. 7 , which images supplied to a digital evaluation device for evaluation.
[0025] The same components are provided with the same reference number in the figures.
DETAILED DESCRIPTION
[0026] FIG. 1 shows a packaging machine in the form of a capsule filling and closing machine 100 . The capsule filling and closing machine 100 has a feed wheel 21 which is rotated in steps on a vertical axis 20 . The capsule filling and closing machine 100 is used for filling and closing capsules c, which consist of a capsule lower part a and a plugged-on cap b. In this case, the capsule c forms a container, which is elongated overall, with a longitudinal axis 15 for a filling material, which in particular is a pharmaceutical product or the like in the form of pieces or powder.
[0027] The feed wheel 21 has stations 1 to 12 which are arranged on the circumferential path of the feed wheel 21 and at which handling devices are arranged. The capsule filling and closing machine 100 which has been described so far is in the form of a standardized packaging machine, as a result of which there is no need to arrange handling devices at all of the stations 1 to 12 , depending on the application. Furthermore, twelve holding segments 22 , which consist of an upper part 27 and a lower part 28 (see station 12 ) are arranged at uniform angular intervals on the external circumference of the feed wheel 21 , for in each case five capsules c, which are arranged in a row. The holding segments 22 are format parts, which can be replaced on the feed wheel 21 , depending on the desired application and depending on the format of the capsules c being processed.
[0028] In order to hold the capsules c, each holding segment 22 in the exemplary embodiment has five holding holes 23 in the upper part 27 and in the lower part 28 . However, holding segments 22 with more than five holding holes 23 arranged in a row, and with more than one row of holding holes 23 , are also possible. The empty capsules c to be filled up are passed in an unorganized form to the station 1 , are aligned, and are supplied in an organized form to the feed wheel 21 . The caps b are then separated from the capsule lower parts a in the area of the station 3 and both are weighed, if required in advance on a sample basis, by a weighing device 25 in order to determine their net weight. In the station 4 , the caps b except for the cover are then fitted to the capsule lower parts a (not illustrated) thus allowing the capsule lower parts 8 to be filled with filling material in the station 5 . In the area of the station 7 , the caps b are once again moved to cover the capsule lower parts a and, in the station 8 , individual capsules c are weighed on a sample basis on a further weighing device 26 process which is gross weighing. In the area of the station 9 , the capsules c are checked for the presence of their caps b, with capsules c and individual capsule lower parts a and caps b being ejected in the area of the station 10 . A sensor apparatus 30 according to the invention is arranged in the area of the station 11 . Finally, the holding segments 22 , which have in the meantime been emptied, are cleaned, in particular by means of airblast, in the area of the station 12 .
[0029] By way of example, reference is furthermore made with respect to the precise operation of a capsule filling and closing machine such as this to DE 10 2005 016 124 A1, from the same applicant, which describes further details relating to the fundamental operation and method of operation thereof.
[0030] As can be seen in particular in FIG. 2 , the sensor apparatus 30 is arranged above the lower parts 28 of the holding segments 22 . The sensor apparatus 30 operates by means of a radiation source, which is in the form of an X-ray radiation source 31 .
[0031] In addition, it should be mentioned, however, that the invention can also in principle operate using different optical inspection processes, for example by means of a through-lighting process with a light source and a camera.
[0032] An ejector pin 33 is arranged underneath the lower parts 28 of the holding segments 22 for each holding hole 23 and aligned with the holding holes 23 , which ejector pin 33 can be moved up and down as indicated by the double-headed arrow 34 , and is aligned with an aperture hole 29 in the lower part 28 . A feed element 35 which is tubular or in the form of a shaft is associated with each holding hole 23 , above and aligned with the holding holes 23 in the holding segments 22 . The longitudinal axis of the feed element 35 is aligned essentially vertically and, at its end facing the holding segment 22 , in each case has a respective clamping piece 36 for each holding hole 23 , which prevents the lowest capsule c from falling out of the feed element 35 back in the direction of the holding hole 23 .
[0033] The X-ray radiation source 31 emits an X-ray radiation lobe 38 , which can be detected by means of a detector 40 , which records and/or processes images, operates in particular digitally, is in the form of an X-ray large-area-sensor and is located on the opposite side of the capsule c to the X-ray radiation source 31 .
[0034] In order to prevent disturbances in the detection of the X-ray radiation lobe 38 in the area of the detector 40 by the feed element 35 , the feed element 35 is designed with suitable measures (for example by means of a plastic design) to allow X-ray radiation to pass through in the area of the X-ray radiation lobe 38 , and it is intended to be expressed by the dashed-line representation of the feed element 35 in the area of the X-ray radiation lobe 38 . Furthermore, according to the invention, it is important that the clamping piece 36 and the feed element 35 are arranged with respect to the X-ray radiation lobe 38 such that, as is shown in FIG. 2 , a capsule c is located completely in the radiation lobe 38 when the lowest of the capsules c, which are positioned one above the other as a row, is held by the clamping piece 36 . An appropriate optic and/or an appropriate arrangement (separation) of the feed element 35 with respect to the X-ray radiation source 31 furthermore ensure that, as far as possible, the X-ray radiation lobe 38 does not cover any areas of capsules c below or above the capsule c that is currently being X-rayed. If this nevertheless were to occur, for example because of tolerances in the length of the capsules c, then, if appropriate, this can be compensated for by appropriate software in the evaluation device 47 , which will be mentioned further below. According to the invention, the feed element 35 is arranged with respect to the X-ray radiation source 31 and with respect to the X-ray radiation lobe 38 such that the X-ray radiation lobe 38 passes through the capsule c at right angles to its longitudinal axis 15 , which means that the detector 40 can record an image corresponding to a longitudinal section through the capsule c.
[0035] The detector 40 and the X-ray radiation source 31 are designed and arranged such that a plurality of capsules c, which are arranged alongside one another at one level, can each be X-rayed by them at the same time, and the X-ray radiation lobe 38 can be detected by the detector 40 .
[0036] In the exemplary embodiment illustrated in FIGS. 1 and 2 , five capsules c are in each case arranged in a row in the holding segments 22 . The sensor apparatus 30 can therefore be used to simultaneously examine all five capsules c in each case in one test step during a phase when the capsules c are stationary in the feed element 35 .
[0037] A segregation device 42 is arranged above the feed element 35 . The segregation device 42 comprises a separately controllable segregation flap 43 for each of the feed elements 35 , which segregation flap 43 is mounted such that it can pivot on an axis 44 and, depending on the position of the segregation flap 43 , segregate individual capsules c in the direction of a good shaft 45 and a bad shaft 46 .
[0038] The sensor apparatus 30 which has been described so far for the capsule filling and closing machine 100 operates as follows: the feed wheel 21 transports the holding segments 22 cyclically below the area of the sensor apparatus 30 . In a phase when the feed wheel 21 is stationary, the capsules c which are located in the holding segment 22 are pushed synchronously by means of the ejector pins 33 out of the holding holes 23 in the lower part 28 of the holding segment 22 , upwards in the direction of the feed elements 35 . In the process, the capsules c which have in each case been pushed out previously still each rest on the clamping pieces 36 and, when subsequent capsules c are pushed in, are shifted further upwards by touching contact between the capsules, by one capsule length in each case. Because of the geometry of the feed elements 35 , capsules c are each still located exactly within the X-ray radiation lobe 38 of the X-ray radiation source 31 . During a phase in which the feed elements 35 are stationary, that is to say when no capsules c are currently being pushed over into the feed element 35 at an instant, the detector 40 in each case records an image of the capsules c which are located within the X-ray radiation lobe 38 , and supplies this to an evaluation device 47 . The evaluation device 47 allows digital evaluation and storage of the recorded image of the X-ray radiation lobe 38 . Once the evaluation device 47 has examined the recorded image for the desired characteristics, in particular with regard to the filling weight, any capsules c which have been identified as “bad capsules c” can be sorted out by means of the segregation device 42 .
[0039] By way of example, FIG. 5 shows six different recordings 51 to 56 , recorded by a detector 40 alongside one another of capsules c filled with different filling materials and of different sizes. Different filling materials and different filling levels and arrangements of the filling materials in the capsules c can be seen in these recordings 51 to 56 . The evaluation program in the evaluation device 47 allows the sensor apparatus 30 to determine not only the respective filling weight of the capsule c, but also in addition to carry out further evaluations. By way of example, the status of the capsule casing (which means identification of defects in the capsule casing, such as cracks, fractures, pinches, deformations, etc.) may be mentioned. It is also possible to detect the state of the filling material, for example whether a pressed item is intact or has been destroyed, or whether a tablet is broken, etc. In principle, the capsule c can also be checked for the presence of the product. By way of example, this includes counting down tablets, microtablets or capsules in the capsule c, or their combinations. In principle, of course, it is also possible to identify capsules c which have not been filled or have been filled incorrectly. By way of example, mention should finally be made of the fact that the capsules c can also be examined for foreign bodies (in particular metal particles). In this case, it is particularly advantageous that the capsule c is detected completely, that is to say over its entire longitudinal extent, by the X-ray radiation lobe 38 , because of the arrangement and configuration of the feed elements 35 , without the capsules c in the process being concealed by parts of the feed elements 35 when lateral guides for the capsules c in the feed elements 35 may, for example, be composed of plastic.
[0040] FIGS. 3 and 4 show a modified sensor apparatus 30 a . In this case, holding segments 22 a and lower parts 28 a are provided which, in contrast to the holding segments 22 , have two rows 48 , 49 of holding holes 23 for capsules c. As can be seen in particular from FIG. 4 , six capsules c are in each case arranged within one holding segment 22 a in each of the rows 48 and 49 in this case. In order nevertheless to make it possible to test the greater number of capsules c, in comparison to the holding segment 22 , in a single test step, provision is made for the capsules c to be pushed over into the individual feed elements 35 by means of a funnel-shaped distributor 50 , such that all twelve capsules c are arranged alongside one another on one plane, as can be seen in particular in FIG. 4 . Because of the relatively large area of the capsules c which are arranged alongside one another, it may be necessary to use a plurality of X-ray radiation sources 31 a , 31 b as well as a plurality of detectors 40 a , 40 b , which are arranged at right angles to the plane of the drawing in FIG. 3 .
[0041] FIG. 6 shows a capsule monitoring apparatus 100 a . The capsule monitoring apparatus 100 a may in this case be a component of an already described capsule filling and closing machine 100 , or may be operated as a separate monitoring apparatus 100 a . A filling material container 60 with capsules c which have already been filled and closed is provided for the capsule monitoring apparatus 100 a . The capsules c are separated from the filling material container 60 by means of a slide 61 which can be moved up and down, and are supplied to the feed element 35 a in a row (or else in a plurality of rows arranged at right angles to the plane of the drawing in FIG. 6 ). A sensor device 30 b is arranged under the filling material container 6 , the function of which sensor device 30 b has already been explained within the description of the capsule filling and closing machine 100 as shown in FIGS. 1 to 5 . In particular, the sensor apparatus 30 b can be used to detect the filling weight and possible damage to and contamination of the capsules c.
[0042] A blocking latch 62 is provided under the sensor apparatus 30 b on the feed element 35 a and in each case releases a capsule c which has previously been examined in the area of the sensor apparatus 30 b , or blocks it. Following the blocking latch 62 , the feed element 35 a has a curved section 63 at whose outlet, and aligned with it, a weighing cell 64 , which is arranged in suspended form, is arranged. The weighing cell 64 is a component of a weighing device 65 , whose exact design and method of operation has already been explained in detail in DE 198 19 395 C1, from the same applicant, and to which reference is therefore made.
[0043] In particular, the weighing device 65 has an impeller wheel 66 which is moved in steps in the counterclockwise direction and with whose aid one capsule c is in each case fed into the area of the weighing cell 64 , and out of it. The weighing device 65 is followed, via a further curved area 67 , by an additional ejection device 68 , which has a moving flap 69 . The flap 69 makes it possible to separate good capsules c from bad capsules c depending on the result of the evaluations, in the area of the sensor apparatus 33 b and of the weighing device 65 .
[0044] In addition, it should be mentioned that the capsule monitoring apparatus 100 a can also be modified such that no filling material container 60 is provided. In this case, the weighing device 65 follows the sensor apparatuses 30 and 30 a , as shown in FIGS. 1 to 3 , and is connected thereto. In other words, this means that a dedicated, separate impeller wheel 66 can be provided for each of the feed elements 35 , with the weighing device 65 then likewise having a dedicated weighing cell 64 for each feed element 35 .
[0045] FIG. 7 shows a sensor apparatus 30 c , which has once again been modified in comparison to FIGS. 3 and 4 . In the sensor apparatus 30 c , a reference object 70 is arranged on each of the two opposite sides in the beam path of the X-ray radiation source (which is not illustrated). Two (identical) reference objects 70 are arranged with a view to in each case detecting and checking six capsules c, in each case by means of a detector 40 a , 40 b . A reference object 70 is therefore associated with each detector 40 a , 40 b . An important factor in this case is that, when using X-rays, the reference object 70 consists of a material which is as similar as possible to the atomic composition of the material to be analyzed, that is to say the material of the capsule c and the capsule content. Furthermore, provision is advantageously made for the reference object 70 to be in the form of a wedge or step. In this case, the reference object 70 is arranged such that the height of the reference object 70 , which is in the form of a wedge or step, varies in the direction in which the radiation from the X-ray radiation source 31 passes through. A further important factor is that the attenuation of the X-ray radiation by the reference object 70 , at least in one area of the reference object 70 , is greater than the greatest attenuation caused by the capsule c (this is dependent on the density, the atomic composition and the thickness of the filling material and capsule c through which the radiation passes). Furthermore, the attenuation of the X-ray radiation by the reference object 70 at another point or on another area of the reference object 70 must be less than the smallest attenuation caused by the capsule c. In this case, any desired number of steps may be implemented between the two attenuation areas mentioned by the reference object 70 being in the form of a wedge or step. FIG. 7 shows two images 72 , 73 , which have been detected by means of two detectors 40 a , 40 b and are fed to the evaluation device 47 , with one reference object 70 , which is in the form of a step or staircase, being used in each case.
[0046] In order to adjust the detectors 40 a , 40 b , it is necessary to be able to remove the reference object 70 from the image 72 , 73 . Furthermore, it is essential that the position and orientation of the reference object 70 does not change during operation of the sensor apparatus 30 c . For starting up, the X-ray camera system, consisting of the X-ray radiation source 31 , 31 a and 31 b and the detector 40 , 40 a and 40 b , is first of all adjusted without the reference object 70 . A reference object 70 and an object to be measured, that is to say a capsule c, are then measured and an image 72 , 73 is recorded. This image 72 or 73 is stored. Radiation is then optionally passed through a second object to be measured and a second capsule c to be measured, and an image 72 , 73 is recorded and stored. The capsule c is then located in the image 72 , 73 . The grayscales of the reference object 70 are read and are linked or related to the actual geometric dimensions of the reference object 70 . The object to be measured, that is to say the capsule c to be measured, is then located in the image 72 , 73 , and its information (for example individual grayscale values, area of the object on the image, etc.) is read by means of the evaluation device 47 from the image 72 , 73 . This object information (for example grayscale values) is converted pixel-by-pixel to a virtual thickness, to be precise using the information from the reference object 70 . The mean value of these virtual individual thicknesses within the selected area can now be associated with the actual gravimetric weight of the capsule c, which was determined using a gravimetric weighing device. The reference object 70 is then located in the second image 72 , 73 . The grayscales of the reference object 70 are likewise read and are compared with the grayscale values of the reference object 70 from the first image. If the grayscale values of the (second) reference object 70 are within a defined limit, the second recorded image 72 , 73 is not corrected. If there is a change in the information, for example the grayscale values of the second reference object 70 outside defined limits, the image 72 , 73 is appropriately corrected. The object (capsule c) to be measured is then located analogously to the manner in the first image 72 , 73 , and its information is read from the image 72 , 73 . In this case as well, the object information is then converted pixel-by-pixel to a virtual thickness, to be precise with the aid of the information from the reference object 70 . The mean value of these virtual individual thicknesses can now be associated with the actual gravimetric weight of the measurement object. If a third object to be measured and a third capsule c to be measured as well as the reference object 70 are now inserted into the X-ray camera system, the system is able to use the information from the two images 72 , 73 , the reference object 70 and the gravimetric weights from the first two weighing processes to determine the weight of the third object (and of any desired number of further objects).
[0047] The capsule filling and closing machine 100 described so far and the capsule monitoring apparatus 100 a can be modified in many ways. However, it is essential to the invention that the radiation sources are arranged with respect to the containers which pass through radiation such that radiation is passed through them at right angles to their longitudinal direction.
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The invention relates to a sensor device ( 30; 30 a ; 30 b ; 30 c ) for a packaging machine ( 100 ) designed as a capsule filling and sealing machine or for a capsule control device ( 100 a ), said device having a positioning element ( 35; 35 a ) for positioning a container (c) having a longitudinal axis ( 15 ) and filled with a filling material in the region of the sensor device ( 30; 30 a ; 30 b ; 30 c ) and at least one radiation source ( 31; 31 a; 3 b ) and at least one detector ( 40; 40 a ; 40 b ) for detecting the radiation after said radiation radiates through the container (c). According to the invention, the at least one radiation source ( 31; 31 a ; 31 b ) radiates through the container (c) perpendicular to the longitudinal axis ( 15 ) thereof and the positioning element is designed as a tubular or shaft-shaped conveying element ( 35; 35 a ) which can be penetrated by the radiation in a radiation cone ( 38 ) of the radiation source ( 31; 31 a ; 31 b ).
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of Ser. No. 13/332,950, filed Dec. 21, 2011, which is a continuation application of Ser. No. 12/816,105, filed Jun. 15, 2010, now issued as U.S. Pat. No. 8,094,691 on Jan. 10, 2012, which is a divisional of U.S. application Ser. No. 12/340,036, filed Dec. 19, 2008, now issued as U.S. Pat. No. 7,782,912 on Aug. 24, 2010, which is a divisional of U.S. application Ser. No. 11/005,218 filed Dec. 7, 2004, now issued as U.S. Pat. No. 7,508,853 on Mar. 24, 2009, the disclosures of which are incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] Regenerative amplifiers utilizing chirped pulse amplification (CPA) have been the dominant means for obtaining pulse energies greater than a microjoule with pulse durations in the femtosecond to picosecond range. Microjoule to millijoule pulse energies with pulse durations below 10 picoseconds have been found to be particularly useful for micromachining and for medical applications such as Lasik. However, a big stumbling block in the utilization of ultrafast sources for these applications has been that the regenerative amplifier is more of a piece of laboratory equipment and not conducive to the industrial setting.
[0003] Alternative sources for microjoule level, ultrafast pulses are emerging; utilizing all fiber chirped pulse amplification designs. Such systems are inherently more stable since they are based on technology similar to that utilized in Telecomm systems. During the past decade, there has been intensive work and success in making such systems practical. However, for higher pulse energies in the millijoule range, regenerative amplifiers will continue to dominate for some time since pulse energies above a millijoule have not been demonstrated in an all fiber system.
[0004] For micromachining applications, more industrially compatible regenerative amplifiers are now being developed based on Nd: or Yb: doped materials, rather than the Ti:sapphire that has dominated the scientific market. There are two basic reasons for this change. Commercial markets typically do not require the shorter pulses that can only be obtained from the Ti:sapphire regenerative amplifier, and the Nd: and Yb: based materials can be directly diode pumped, which makes these systems more robust and less expensive. An unresolved technical issue for Nd: or Yb: based regenerative amplifiers is the need for an equally robust seed source for femtosecond or picosecond pulses. The present seed lasers are mode-locked solid-state lasers with questionable reliability. It would be preferable to have a robust fiber seed source similar to that which has been developed for the Ti:sapphire regenerative amplifier, and used where Ti:sapphire regenerative amplifiers are applied to more commercial applications.
[0005] In a copending U.S. application Ser. No. 10/960,923, filed which is assigned to the common assignee and the disclosure of which is incorporated by reference in its entirety, the design changes needed for a mode-locked Yb:doped fiber oscillator and amplifier to be utilized as a seed source for a Yb: or Nd: based solid-state regenerative amplifier are described. The purpose of this application is to modify and apply many of the improvements in all fiber chirped pulse amplification systems for application to the seed source of a regenerative amplifier.
SUMMARY OF THE INVENTION
[0006] The purpose of this invention is to incorporate the many recent improvements in femtosecond mode-locked fiber lasers and femtosecond fiber chirped pulse amplification systems to regenerative amplifier systems that incorporate femtosecond or picosecond pulse sources based on fiber seed-sources and/or fiber amplifiers.
[0007] Yb: and Nd: mode-locked oscillators with fiber amplifiers can be utilized as sources of ultrafast pulses for regenerative amplifiers in order to obtain higher pulse energies than can be realized at this time from all fiber short pulse systems. A8827 (incorporated by reference herein) describes specifically how the sources can be configured to be implemented in such fiber based seed sources for solid state regenerative amplifiers. The femtosecond source and fiber amplifier need to be carefully configured in order to obtain optimum, reliable performance when incorporated into such a system. Recently there have been many improvements in mode-locked fiber sources implemented with fiber amplifiers in chirped pulse amplifier systems that can be utilized in a regenerative amplifier system that typically is based on chirped pulse amplification. Applicable improvements to fiber mode-locked sources are disclosed in Ser. Nos. 09/576,772, 09/809,248, 10/627,069, 10/814,502 and 10/814,319 (all incorporated by reference herein). Alternative suitable femtosecond sources that utilize fiber amplification for pulse conditioning and shortening are described in Ser. No. 10/437,057. One of the difficulties with chirped pulse amplification systems has been in producing reliable and compact pulse stretchers that can be dispersion matched to pulse compressors suitable for high pulse energies.
[0008] Significant improvements for dispersion matched fiber stretchers for fiber based chirped pulse amplification are disclosed in Attorney Docket No. A8717, filed Nov. 22, 2004 (incorporated by reference herein). These improvements are also applicable to chirped pulse amplification systems even when solid state bulk mode-locked lasers are utilized as the seed source. Significant improvements have been made in packaging, electronic controls, fabrication processes and optical parameter controls in order to make fiber based femtosecond sources reliable. These engineering improvements can also be utilized in these regenerative amplifier systems and are disclosed in Ser. Nos. 10/606,829, 10/813,163, 10/813,173 and Attorney Docket No. A8828 (all incorporated by reference herein).
[0009] Previously, Yb: and Nd: mode-locked oscillators and fiber amplifiers have been utilized as pulse sources for narrow bandwidth, bulk, solid-state amplifiers including regenerative amplifiers that can produce pulses 20 picoseconds or greater. In general, the configuration solutions for these longer pulse sources as described, for example in Ser. No. 10/927,374 (incorporated by reference herein) are different than those described here for sub-picosecond systems. However, the engineering improvements described here will also be applicable for the longer pulse systems, and the bulk amplifier operated as a regenerative amplifier has increased flexibility.
[0010] The first important element for a short pulse regenerative amplifier system is the source of short pulses. Femtosecond mode-locked fiber lasers are a good source of such pulses. Typically the fiber oscillator is low power and needs additional amplification for application as a seed source. Other important needs are pulse compression, wavelength flexibility, dispersion control and fiber delivery.
[0011] Therefore, it is an object of the present invention to introduce a modular, compact, widely-tunable, high peak and high average power, low noise ultrafast fiber amplification laser system suitable for a seed source for a regenerative amplifier.
[0012] It is a further object of the invention to ensure modularity of the system by employing a variety of easily interchangeable optical systems, such as 1) short pulse seed sources, 2) wide bandwidth fiber amplifiers, 3) dispersive pulse stretching elements, 4) dispersive pulse compression elements, 5) nonlinear frequency conversion elements and 6) optical components for fiber delivery. In addition, any of the suggested modules can be comprised of a subset of interchangeable optical systems.
[0013] It is a further object of the invention to ensure system compactness by employing efficient fiber amplifiers, directly or indirectly pumped by diode lasers as well as highly integrated dispersive delay lines. The high peak power capability of the fiber amplifiers is greatly expanded by using parabolic or other optimized pulse shapes. In conjunction with self-phase modulation, parabolic pulses allow for the generation of large-bandwidth high-peak power pulses, as well as for well-controlled dispersive pulse stretching. High power parabolic pulses are generated in high-gain single or multi-mode fiber amplifiers operating at wavelengths where the fiber material dispersion is positive.
[0014] Parabolic pulses can be delivered or transmitted along substantial fiber lengths even in the presence of self-phase modulation or general Kerr-effect type optical nonlinearities, while incurring only a substantially linear pulse chirp. At the end of such fiber delivery or fiber transmission lines, the pulses can be compressed to approximately their bandwidth limit.
[0015] Further, the high energy capability of fiber amplifiers is greatly expanded by using chirped pulse amplification in conjunction with parabolic pulses or other optimized pulse shapes, which allow the toleration of large amounts of self-phase modulation without a degradation of pulse quality. Highly integrated chirped pulse amplification systems are constructed without compromising the high-energy capabilities of optical fibers by using fiber-based pulse stretchers in conjunction with bulk-optic pulse compressors (or low nonlinearity Bragg gratings) or periodically poled nonlinear crystals, which combine pulse compression with frequency-conversion.
[0016] The dispersion in the fiber pulse stretcher and bulk optic compressor is matched to quartic order in phase by implementing fiber pulse stretchers with adjustable 2nd, 3rd and 4th order dispersion. Adjustable higher-order dispersion can be obtained by using high numerical aperture single-mode fibers with optimized refractive index profiles by itself or by using standard step-index high numerical aperture fibers in conjunction with linearly chirped fiber gratings. Alternatively, higher-order dispersion can be controlled by using the dispersive properties of the higher-order mode in a high numerical aperture few-moded fiber, by using nonlinearly chirped fiber gratings or by using linearly chirped fiber gratings in conjunction with transmissive fiber gratings. Adjustable 4th order dispersion can be obtained by controlling the chirp in fiber Bragg gratings, transmissive fiber gratings and by using fibers with different ratios of 2 nd , 3 rd and 4 th order dispersion. Equally, higher-order dispersion control can be obtained by using periodically poled nonlinear crystals.
[0017] The fiber amplifiers are seeded by short pulse laser sources, preferably in the form of short pulse fiber sources. For the case of Yb fiber amplifiers, Raman-shifted and frequency doubled short pulse Er fiber laser sources can be implemented as widely tunable seed sources. To minimize the noise of frequency conversion from the 1.5 μm to the 1.0 μm regime, self-limiting Raman-shifting of the Er fiber laser pulse source can be used. Alternatively, the noise of the nonlinear frequency conversion process can be minimized by implementing self-limiting frequency-doubling, where the center wavelength of the tuning curve of the doubling crystal is shorter than the center wavelength of the Raman-shifted pulses.
[0018] The process of Raman-shifting and frequency-doubling can also be inverted, where an Er fiber laser is first frequency-doubled and subsequently Raman-shifted in an optimized fiber providing soliton-supporting dispersion for wavelengths around 800 nm and higher to produce a seed source for the 1 μm wavelength regime.
[0019] As an alternative low-complexity seed source for an Yb amplifier, a modelocked Yb fiber laser can be used. The fiber laser can be designed to produce strongly chirped pulses and an optical filter can be incorporated to select near bandwidth-limited seed pulses for the Yb amplifier.
[0020] Presently the mode-locked Yb: doped fiber laser is the preferred oscillator. The preferred source is described Ser. No. 10/627,069 (incorporated herein).
[0021] The present invention is similarly directed to a mass-producible passively modelocked fiber laser. By incorporating apodized fiber Bragg gratings, integrated fiber polarizers and concatenated sections of polarization-maintaining and non-polarization-maintaining fibers, a fiber pig-tailed, linearly polarized output can be readily obtained from the laser. By further matching the dispersion value of the fiber Bragg grating to the inverse, or negative, of the dispersion of the intra-cavity fiber, the generation of optimally short pulses with a large optical bandwidth can be induced. In this regard, either positive dispersion in conjunction with negative dispersion fiber gratings or negative dispersion in conjunction with positive dispersion fiber gratings can be implemented. Preferably, the dispersion characteristics of the fiber Bragg grating and the dispersion characteristics of the rest of the intra-cavity elements are matched to within a factor of three. Even more preferably, these characteristics are matched within a factor of two, or within a factor in the range of 1.0 to 2.0. Also preferably, the Bragg grating has a chirp rate greater than 80 nm/cm. More preferably, the Bragg grating has a chirp rate greater than 160 nm/cm. Most preferably, the Bragg grating has a chirp rater greater than 300 nm/cm. To maximize the output power and the pulse repetition rate, the use of wide-bandwidth fiber Bragg gratings with low absolute dispersion is preferable. These fiber Bragg gratings are also used as end-minors for the cavity and allow the transmission of pump light to the intra-cavity gain fiber. The fiber Bragg gratings are conveniently produced using phase masks.
[0022] Alternatively, fiber couplers can be used inside the fiber cavity. Generally, sections of polarization-maintaining and non-polarization-maintaining fiber can be concatenated inside the fiber cavity. The non-polarization-maintaining section should then be short enough so as not to excessively perturb the polarization state. Intra-cavity sections of non-polarization-maintaining fiber preferably comprise all-fiber polarizers to lead to preferential oscillation of one linear polarization state inside the cavity. Similarly, when directly concatenating polarization-maintaining fiber sections, the length of the individual section should be long enough to prevent coherent interactions of pulses propagating along the two polarization axes of the polarization-maintaining fibers, thereby ensuring a maximum in pulse stability.
[0023] Saturable absorber mirrors (SAMs) placed inside the cavity enable passive modelocking. The saturable absorbers (SA) can be made from multiple quantum wells (MQW) or bulk semiconductor films. These saturable absorbers have preferably a bi-temporal life-time with a slow component (>>100 ps) and a fast component (<<20 ps). The realization of the bi-temporal dynamics of the optical nonlinearity is achieved by tailoring the depth profile of the ion-implantation in combination with the implantation dose and energy. The result is that the carriers trap at distinctively different rates in different depth regions of the SAM.
[0024] Saturating semiconductor films can for example be grown from aluminum-containing material such as AlGaInAs, the exact composition can be selected depending on the sought band-gap (typically selected to be in the vicinity of the desired operating wavelength of the laser system) and it is also governed by the requirement of lattice-match between the saturating semiconductor film and an underlying Bragg minor or any other adjacent semiconductor material. Compositional requirements enabling lattice match between semiconductors and/or a certain band gap are well known in the state of the art and are not further explained here.
[0025] In aluminum containing semiconductors the surface area can induce a low optical damage threshold triggered by oxidization of the surface. In order to prevent optical damage of aluminum containing surface areas a passivation layer, e.g., InP, InGaAs or GaAs, is incorporated. SA degradation is further minimized by optimizing the optical beam diameter that impinges on the SAM. In one implementation the SAM and an intra-cavity fiber end can be either butt-coupled or brought into close contact to induce modelocking. Here, the incorporation of a precision AR-coating on the intra-cavity fiber end minimizes any bandwidth restrictions from etalon formation between the SAM and the fiber end. Etalons can also be minimized by appropriate wedging of the fiber ends. The beam diameter inside the SAM can be adjusted by implementing fiber ends with thermally expanded cores. Alternatively, focusing lenses can be directly fused to the fiber end. Moreover, graded-index lenses can be used for optimization of the focal size and working distance between the fiber tip and SA surface.
[0026] Wavelength tuning of the fiber lasers can be obtained by heating, compression or stretching of fiber Bragg gratings or by the incorporation of bulk optic tuning elements.
[0027] The use of bi- or multi-temporal saturable absorbers allows the design of dispersion compensated fiber laser operating in a single-polarization state, producing pulses at the bandwidth limit of the fiber gain medium.
[0028] Further improvement of the femtosecond Yb doped fiber oscillator can include an integral mass produced master oscillator, power amplifier design (MOPA) which is describe in Ser. No. 10/814,502 (incorporated by reference herein).
[0029] One embodiment of the present invention comprises a master oscillator power amplifier comprising a mode-locked fiber oscillator and a fiber amplifier. The mode-locked fiber oscillator comprises a pair of reflective optical elements that form an optical resonator. At least one of the reflective optical elements is partially transmissive and has a reflection coefficient that is less than about 60%. The mode-locked fiber oscillator outputs a plurality of optical pulses. The fiber amplifier is optically connected to the mode-locked fiber oscillator through a bi-directional optical connection such that light from the mode-locked fiber oscillator can propagate to the fiber amplifier and light from the fiber amplifier can propagate to the mode-locked fiber oscillator.
[0030] Another embodiment of the present invention comprises a method of producing laser pulses. In this method, optical energy is propagated back and forth through a gain fiber by reflecting light from a pair of reflective elements on opposite ends of the gain fiber. Less than about 60% of the light in the gain fiber is reflected back into the gain fiber by one of the reflectors. The pair of reflective elements together form a resonant cavity that supports a plurality of resonant optical modes. The resonant optical modes are substantially mode-locking to produce a train of pulses. The train of optical pulses is propagated from the laser cavity through one of the reflectors to a fiber amplifier along a bi-directional optical path from the laser cavity to the fiber amplifier where the laser pulses are amplified.
[0031] Another embodiment of the present invention comprises a fiber-based master oscillator power amplifier comprising a mode-locked fiber oscillator, a fiber amplifier comprising a gain fiber, and bi-directional optical path between the mode-locked fiber oscillator and the fiber amplifier. The mode-locked fiber oscillator comprises a resonant cavity and a gain medium. The mode-locked fiber oscillator produces a plurality of optical pulses. The bi-directional optical path between the mode-locked fiber oscillator and the fiber amplifier permits light from the mode-locked fiber oscillator to propagate to the fiber amplifier and light from the fiber amplifier to propagate to the mode-locked fiber oscillator. The mode-locked fiber oscillator comprises a first segment of fiber and the fiber amplifier comprises a second segment of optical fiber. The first and second segments form a substantially continuous length of optical fiber. In some embodiments, the first and second segments are spliced together. The first and second segments may be fusion spliced. The first and second segments may also be butt coupled together with or without a small gap, such as a small air gap, between the first and second segments.
[0032] Another embodiment of the present invention comprises a method of producing laser pulses comprising substantially mode-locking longitudinal modes of a laser cavity to produce laser pulses and propagating the laser pulses from the laser cavity to a fiber amplifier. The laser pulses are amplified in the fiber amplifier. Amplified spontaneous emission emitted from the fiber amplifier is received at the laser cavity. A first portion of the spontaneous emission enters the laser cavity. A second portion of the amplified spontaneous emission from the laser cavity is retro-reflected back to the fiber amplifier to cause the second portion to be directed away from the cavity toward the fiber amplifier.
[0033] Another embodiment of the present invention comprises a fiber master oscillator power amplifier comprising a mode-locked fiber oscillator and a fiber amplifier. The mode-locked fiber oscillator comprises a first portion of optical fiber and a pair of reflectors spaced apart to form a fiber optic resonator in the first fiber portion. At least one of the fiber reflectors comprises a partially transmissive fiber reflector. The mode-locked fiber oscillator outputs a plurality of optical pulses. The fiber amplifier comprises a second portion of optical fiber optically connected to the partially transmissive fiber reflector to receive the optical pulses from the mode-locked oscillator. The second portion of optical fiber has gain to amplify the optical pulses. The first portion of optical fiber, the partially transmissive fiber reflector, and the second portion of optical fiber comprise a continuous path formed by optical fiber uninterrupted by non-fiber optical components.
[0034] Another embodiment of the present invention comprises a master oscillator power amplifier comprising a mode-locked fiber oscillator and a fiber amplifier. The mode-locked fiber oscillator comprises a pair of reflective optical elements that form an optical resonator. At least one of the reflective optical elements comprises a partially transmissive Bragg fiber grating having a reflection coefficient that is less than about 60%. The mode-locked fiber oscillator outputs a plurality of optical pulses. A fiber amplifier is optically connected to the oscillator through an optical connection to the partially transmissive Bragg fiber grating.
[0035] Another embodiment of the present invention comprises a master oscillator power amplifier comprising a mode-locked fiber oscillator, a fiber amplifier, and a pump source. The mode-locked fiber oscillator comprises a pair of reflective optical elements that form an optical resonator. At least one of the reflective optical elements is partially transmissive and has a reflection coefficient that is less than about 60%. The mode-locked fiber oscillator outputs a plurality of optical pulses. A fiber amplifier is optically connected to the oscillator through an optical connection to the at least one partially transmissive reflective optical elements. The pump source is optically connected to the mode-locked fiber oscillator and the fiber amplifier to pump the mode-locked fiber oscillator and the fiber amplifier.
[0036] However, for most embodiments for a source for a regenerative amplifier the pulses need to be conditioned before amplification. Ser. No. 10/814,319 (incorporated by reference herein) addresses the utilization of modules so that the correct performance can be obtained from the femtosecond source for the seeder or a portion of the seeder for the regenerative amplifier system. Parameter controls available through these modules can be utilized for the optimization of the output from the regenerative amplifier.
[0037] One embodiment of the invention thus comprises a pulsed fiber laser outputting pulses having a duration and corresponding pulse width. The pulsed laser comprises a modelocked fiber oscillator, an amplifier, a variable attenuator, and a compressor. The modelocked fiber oscillator outputs optical pulses. The amplifier is optically connected to the modelocked fiber oscillator to receive the optical pulses. The amplifier comprises a gain medium that imparts gain to the optical pulse. The variable attenuator is disposed between the modelocked fiber oscillator and the amplifier. The variable attenuator has an adjustable transmission such that the optical energy that is coupled from the mode-locked fiber oscillator to the amplifier can be reduced. The compressor compresses the pulse thereby reducing the width of the pulse. Preferably a minimum pulse width is obtained.
[0038] Another embodiment of the invention comprises a method of producing compressed high power short laser pulses having an optical power of at least about 200 mW and a pulse duration of about 200 femtoseconds or less. In this method, longitudinal modes of a laser cavity are substantially mode-locked to repetitively produce a laser pulse. The laser pulse is amplified. The laser pulse is also chirped thereby changing the optical frequency of the optical pulse over time. The laser pulse is also compressed by propagating different optical frequency components of the laser pulse differently to produce compressed laser pulses having a shortened temporal duration. In addition, the laser pulse is selectively attenuated prior to the amplifying of the laser pulse to further shorten the duration of the compressed laser pulses.
[0039] Another embodiment of the invention comprises a method of manufacturing a high power short pulse fiber laser. This method comprises mode-locking a fiber-based oscillator that outputs optical pulses. This method further comprises optically coupling an amplifier to the fiber-based oscillator through a variable attenuator so as to feed the optical pulses from the fiber-based oscillator through the variable attenuator and to the amplifier. The variable attenuator is adjusted based on a measurement of the optical pulses to reduce the intensity of the optical pulses delivered to the amplifier and to shorten the pulse.
[0040] Another embodiment of the invention comprises a pulsed fiber laser outputting pulses having a pulse width. The pulsed fiber laser comprises a modelocked fiber oscillator, an amplifier, and a spectral filter. The modelocked fiber oscillator produces an optical output comprising a plurality of optical pulses having a pulse width and a spectral power distribution having a bandwidth. The amplifier is optically connected to the modelocked fiber amplifier for amplifying the optical pulses. The spectral filter is disposed to receive the optical output of the modelocked fiber oscillator prior to reaching the amplifier. The spectral filter has a spectral transmission with a band edge that overlaps the spectral power distribution of the optical output of the modelocked fiber oscillator to attenuate a portion of the spectral power distribution and thereby reduce the spectral bandwidth. The pulse width of the optical pulses coupled from the mode locked fiber oscillator to the fiber amplifier is thereby reduced.
[0041] Another embodiment of the invention comprises a method of producing compressed optical pulses. In this method, longitudinal modes of a fiber resonant cavity are substantially mode-locked so as to produce a train of optical pulses having a corresponding spectral power distribution with a spectral bandwidth. The optical pulses are amplified and compressed to produce compressed optical pulses. The spectral bandwidth of the spectral power distribution is reduced such that the compressed optical pulses have a shorter duration.
[0042] Another embodiment of the invention comprises a pulsed fiber laser comprising a modelocked fiber oscillator, an amplifier, one or more optical pump sources, a pulse compressor, and a pre-compressor. The modelocked fiber oscillator comprises a gain fiber and a pair of reflective optical elements disposed with respect to the gain fiber to form a resonant cavity. The modelocked fiber oscillator produces a train of optical pulses having an average pulse width. The amplifier is optically connected to the modelocked fiber amplifier such that the optical pulses can propagate through the amplifier. The fiber amplifier amplifies the optical pulses. The one or more optical pump sources are optically connected to the modelocked fiber oscillator and the fiber amplifier to pump the fiber oscillator and fiber amplifier. The pulse compressor is optically coupled to receive the amplified optical pulses output from fiber amplifier. The pulse compressor shortens the pulse width of the optical pulses output by the fiber amplifier. The pre-compressor is disposed in an optical path between the modelocked fiber oscillator and the fiber amplifier. The pre-compressor shortens the duration of the optical pulses introduced into the fiber amplifier such that the pulse duration of the optical pulses output by the compressor can be further shortened.
[0043] Another embodiment of the invention comprises a method of generating short high power optical pulses. The method comprises substantially mode-locking optical modes of a laser cavity to produce an optical signal comprising a plurality of laser pulses having an average pulse width. The optical signal comprises a distribution of frequency components. The method further comprises compressing the optical pulses and amplifying the compressed optical pulses to produce amplified compressed optical pulses. The amplified compressed optical pulses are further compressed subsequent to the amplifying using a dispersive optical element to differentiate between spectral components and introducing different phase shifts to the different spectral components.
[0044] Another embodiment of the invention comprises a pulsed fiber laser comprising a modelocked fiber oscillator, a fiber amplifier, an optical pump source, and a pulse compressor. The modelocked fiber oscillator outputs optical pulses. The fiber amplifier is optically connected to the modelocked fiber oscillator and amplifies the optical pulses. The optical pump source is optically connected to the fiber amplifier. The pulse compressor is optically coupled to receive the amplified optical pulses output from the fiber amplifier. The pulsed fiber laser further comprises at least one of (i) a first optical tap in the optical path between the modelocked fiber oscillator and the fiber amplifier and a first feedback loop from the first tap to control the modelocked fiber oscillator based on measurement of output from the first optical tap, and (ii) a second optical tap in the optical path between the fiber amplifier and the compressor and a second feedback loop from the second tap to control the fiber amplifier based on measurement of output from the first optical tap.
[0045] Another embodiment of the invention comprises a pulsed light source comprising a light source module, an isolator module, an amplifier module, and a compressor module. The light source module comprises an optical fiber and outputs optical pulses. The isolator module comprises an optical isolator in a housing having input and output fibers. The input fiber is optically coupled to the optical fiber of the light source module. The optical isolator is disposed in an optical path connecting the input and output fibers such that the optical pulses introduced into the input fiber are received by the isolator and permitted to continue along the optical path to the output coupler. The amplifier module comprises an amplifying medium and has an optical input optically connected to the output fiber of the isolator module to amplify the optical pulses. The compressor module is optically coupled to the amplifier module to compress the optical pulses.
[0046] Up to this point a mode-locked fiber laser or a bulk solid state mode-locked laser as the seed source for the fiber amplifier and regenerative amplifier has been disclosed. Other sources can also be utilized such a laser-diodes or microchip lasers. In Ser. No. 10/437,057 (incorporated by reference herein), it is disclosed how to modify these sources to give higher energy and shorter pulses through amplification and pulse compression in fiber amplifiers. An advantage of these sources that is mentioned in Ser. No. 10/437,057 is the repetition rate can be variable. It is a true advantage to match the repetition rate of the source to that of the regenerative amplifier.
[0047] Thus, one object of this invention is to convert relatively long pulses from rep-rate variable ultrafast optical sources to shorter, high-energy pulses suitable for seed sources in high-energy ultrafast lasers including a regenerative amplifier. Another object of this invention is to take advantage of the need for higher pulse energies at lower repetition rates so that such sources can be cost effective.
[0048] A gain switched laser diode as is used in telecom systems can be used as the initial source of pulses. In this case, the diode is operated at a much lower repetition rate. The pulses are still amplified in fiber amplifiers. Fiber amplifiers can be used as constant output power devices. The upper-state lifetime in typical doped amplifier fibers such as Ytterbium and Erbium is in the millisecond range so that these amplifiers can amplify pulse trains with the same efficiency at repetition rates from 10's of kHz to 100's of GHz and beyond. If the amplifier is amplifying pulses at 10 kHz rather than at 10 GHz at constant power, then the pulse energy will be six orders of magnitude higher. Again, with such high peak powers, pulse compression methods need to be different and unique. One first embodiment uses conventional compression by spectral broadening the pulses in an optical fiber with positive group velocity dispersion (GVD) and then compressing the pulse with diffraction gratings. The object of the pulse compression is to convert the 3-25 picosecond pulses from the gain switched laser diode to pulses that are subpicosecond.
[0049] Another source starts with pulses from a low cost Q-switched microchip laser. These lasers give pulses as short as 50 picoseconds but typically 250 picoseconds to 1.0 nanosecond. The pulse peak powers are typically 1-10 kW with pulse energies 6 orders of magnitude higher than from telecom laser diodes. Microchip lasers could be a very cost effective source for pulses less than 10 picoseconds with suitable pulse compression methods. Single mode fiber compression has thus far been limited to pulses shorter than 150 ps and peak powers less than 1 kW. Before compression the pulse can be further amplified in a regenerative amplifier.
[0050] Once a suitable femtosecond source has been identified further improvements have been made in the incorporation of these lasers in chirped pulse amplification systems where the amplifier has been a fiber amplifier. In Ser. No. 10/813,163, many improvements to the fiber chirped pulse amplification (FCPA) configuration have been made for a configuration that is more robust and suitable to an industrial environment. Here it has been realized that these improvements can be also utilized for fiber lasers seeding solid state amplifiers and particular solid state regenerative amplifiers. Specifically, the improvements for the FCPA configuration that are disclosed in Ser. No. 10/813,163 can be utilized in a regenerative amplifier seeded with a fiber laser configuration. The simplest embodiments are for the replacement of the power amplifier in FIGS. 1 and 11 of this application with a regenerative amplifier.
[0051] The following topics that are covered in Ser. No. 10/813,163 are relevant to this configuration.
1) Functional segmentation of opto-mechanical components into modular devices to produce manufacturable industrial laser systems with Telcordia-grade quality and reliability. 2) Polarization fidelity within and between modules 3) Provision for tap units for test, monitoring or feedback 4) Spectral matching of oscillator to amplifier 5) Selection of the length of an amplifier to cut ASE at the lasing wavelength 6) Active stabilization of the optical performance of gain fiber in a laser or amplifier. The stabilization is realized by actively adjusting the pump source wavelength by changing the source temperature in order to match pump wavelength with the absorption spectrum of the gain medium. The temperature dependent spectrum in the gain fiber is cloned in the same type of fiber, and thus used as a monitor. Accurate control of the gain performance over a wide range of operating temperatures is possible implementing this method. 7) Extraction of one or more chirped pulses from a series of such pulses using an acousto-optic deflector, and compensation for detrimental effects on the spatial characteristics of the extracted chirped pulse, caused by dispersion in that deflector.
[0059] The invention thus relates to the technologies necessary to overcome the above problems and limitations of the prior art, to build a hybrid fiber and solid-state based chirped pulse amplification laser system suitable for industrial applications, with the fiber in a modular and compact laser design with all modules replaceable. The modules are designed and manufactured to telecom standards and quality.
[0060] Environmentally stable laser design is crucial for industrial application. An industrial laser system can be, for example, characterized by an output power variation below 0.5 dB over an environmental temperature range from 0 to 50 degrees Celsius, and by compliance with the vibration, thermal shock, high temperature storage and thermal cycling test criteria in Telcordia GR-468-CORE and GR-1221-CORE. This target can be achieved by functional segmentation of the components and packaging the modular device with Telcordia-qualified packaging technology. Before the modules are assembled into a system, they are tested and assembled separately.
[0061] Included in the modules are tap units that allow taking out signals along the propagation path in an integrated design. This is necessary for the optimization of each module as it is assembled, and important in the spectral matching along the chain of modules.
[0062] Polarization units are provided to prevent the buildup of side-pulses from orthogonal polarization light.
[0063] The acousto-optical down counter module can be designed to operate as a bandwidth filter. For further modulation of the signal an additional pulse extractor can be included near the end of the output. This unit suffers from dispersion due to the large bandwidth of the pulse. The compressor can be used to correct for this dispersion as disclosed hereafter.
[0064] The invention also relates to a means to extract one or more chirped pulses from a series of such pulses using an acousto-optic deflector, and to compensate for the detrimental effects on the spatial characteristics of the extracted chirped pulse caused by dispersion in that deflector. An important aspect of this system is to manage the spectrum of the pulse in the system while maintaining the ability to correct for dispersion and compress the pulse back to the femtosecond regime. Two principal embodiments of this type will be described. The first is the case where the spectral content of the seed pulse is small. In this case a nonlinear amplifier may be employed for the generation of additional spectrum while spectral filtering is employed to obtain a compressible pulse. The second case is where the spectrum from the source is larger than necessary. Nonlinear affects can be limited in the amplifier chain in this case, while spectral filtering is again employed to obtain a compressible pulse. An additional attribute that is necessary for many applications is the reduction of the ASE at the output. Specific amplifier designs are used to cut the ASE at the output wavelength. The compressor can be used as an optical spectral filter to this end.
[0065] Once gain performance is attained, a method for active stabilization of the optical performance of the gain fiber in a laser or amplifier is disclosed to maintain this performance. The present invention stabilizes the temperature dependent absorption of a gain fiber over a wide environmental temperature variation by an active feedback loop. A piece of fiber, optically identical with the gain fiber itself, is used as a spectral filter for monitoring the emission spectrum of the pump diode. The absorption spectrum of the filter fiber follows that of the gain fiber if both fibers are packaged so that the fibers are in proximity to each other. The transmission of the pump light through the filter fiber clones exactly the absorption characteristics of the gain fiber at a given package temperature. The temperature of the pump diode is controlled by a feedback loop such that the transmission through the filter fiber is maintained at the minimum. Importantly, the filter fiber functions as an active temperature sensor of the gain fiber. Precise spectral control of the gain at any fiber or package temperature can thus be realized.
[0066] As mentioned above, an important field of use for this system is in micromachining. An additional feature needed for this application field is the capability to start and stop the pulse stream while moving the targeted material in place. One method to do this is to control the down counter. However, this leads to problems with gain stabilization in the amplifier and excessive ASE on target. These problems have been addressed in Ser. No. 10/813,173 “Method and Apparatus for Controlling and Protecting Pulsed High Power Fiber Amplifier Systems” (incorporated by reference herein). However, another means to stop the pulse stream is to utilize an optical switch at the output.
[0067] The invention extracts one or more chirped pulses from a series of such pulses using an acousto-optic deflector, and compensates for the detrimental effects on the spatial characteristics of the extracted chirped pulse caused by dispersion in that deflector. The instant invention has the additional advantage that the means to compensate for dispersion in the acousto-optic deflector can be used to compress the duration of the chirped pulse. This is accomplished by placing the AOM in proximity to a grating compressor.
[0068] Further improvements for correction of higher order dispersion terms in fiber chirped pulse amplification systems are disclosed in Attorney Docket No. A8717 (incorporated by reference herein). These can be applied to chirped pulse amplification systems with regenerative amplifiers.
[0069] Here, an ultra-compact high energy chirped pulse amplification systems based on linearly or nonlinearly chirped fiber grating pulse stretchers and photonic crystal fiber pulse compressors. Alternatively, photonic crystal fiber pulse stretchers and photonic crystal fiber compressors can also be implemented. For industrial applications the use of all-fiber chirped pulse amplification systems is preferred, relying on fiber-based pulse compressors and stretchers as well as fiber-based amplifiers.
[0070] Fiber-based high energy chirped pulse amplification systems of high utility can also be constructed from conventional optical components such as pulse stretchers based on long lengths of conventional fiber as well as bulk grating compressors. The performance of such ‘conventional’ chirped pulse amplification systems can be greatly enhanced by exploiting nonlinear cubicon pulse formation, i.e. by minimization of higher-order dispersion via control of self-phase modulation inside the amplifiers.
[0071] Finally, a particularly compact seed source for an Yb fiber-based chirped pulse amplification system can be constructed from an anti-Stokes frequency shifted modelocked Er fiber laser amplifier system, where a wavelength tunable output is obtained by filtering of the anti-Stokes frequency shifted output. The noise of such an anti-Stokes frequency shifted source is minimized by the amplification of positively chirped pulses in a negative dispersion fiber amplifier.
[0072] The preceding improvements have been focused on systems operating close to 1 μm. These systems appear to be the most suitable for industrial applications. However, Ti:sapphire regenerative amplifiers are presently the dominant design. Frequency doubled erbium fiber lasers are utilized for the more industrial Ti:sapphire systems. FCPA front ends are suitable for higher repetition rates utilizing an electro-optic pulse selector as is disclosed in Ser. No. 10/960,923. FCPA systems operating in the 1.5 telecomm wavelength which are then frequency doubled would be suitable for a Ti:sapphire amplifier or regenerative amplifier system.
[0073] The invention in Ser. No. 10/606,829 (incorporated by reference herein) provides an erbium fiber (or erbium-ytterbium) based chirped pulse amplification system operating at a wavelength of approximately 1550 nanometers. The use of fiber amplifiers operating in the telecommunications window enables telecommunications components and telecommunications compatible assembly procedures to be used, with superior mechanical stability
[0074] It is found that electronic controls are needed for reliable operation for these complex systems. In Ser. No. 10/813,173 (incorporated by reference herein), the implementation of electronic controls are described which prevent catastrophic damage in a short pulse amplifier system as well as maintaining constant output power over the life of the system. These systems are very applicable in a regenerative amplifier system seeded by a fiber laser. The damage issues will also be a concern in a regenerative amplifier system. However, more importantly these front end systems normally will encompass nonlinear optical processes in the fiber amplifiers. These nonlinear optical processes are very dependent on laser intensity. Thus, to maintain the desired results over the life of the system, careful control of the optical powers is needed particularly in the nonlinear optical components in the system.
[0075] It is thus an object of the present invention to provide a high power fiber amplifier system with means for controlling the pump diode current and the gain of the fiber amplifier such that the output pulse energy is constant as the pulse width and repetition rate are adjusted during operation. This includes keeping the pulse energy constant during turn-on of the pulse train.
[0076] It is a further object of the invention to provide means for controlling the temperature of the fiber amplifier pump diode such that the pump diode wavelength is maintained at a fixed value with changes in diode current.
[0077] It is also an object of the invention to provide means for protecting the high power amplifier from damage due to gain buildup in excess of the damage threshold of the amplifier by monitoring the repetition rate of the injected oscillator pulses or external signal, and shutting off or reducing the pump diode current if the repetition rate falls below this threshold.
[0078] It is also an object of the invention to provide for monitoring of the amplitude of the seed pulses and to protect the high power fiber amplifier from damage by shutting off the pump diode if the amplitude of the injected pulses falls outside a safe threshold.
[0079] It is also an object of the invention to provide a high power amplifier system with means for controlling the amplitude of the seed pulse such that the output energy of the power amplifier is constant.
[0080] The above and other objects of the invention are met by providing a device and method for controlling the diode current of the pump diode in a high power fiber amplifier, the device comprising a means for setting the pump diode current or power, monitoring such current or power, and maintaining the diode current or power at a constant value. Typically the current of the diode is controlled to correct for long term decrease on its output due to aging. In contrast, in accordance with an embodiment of the present invention, the pump diode current is controlled to dynamically control the gain of the power amplifier to maintain uniform pulse energy as the repetition rate and the pulse temporal width is changed. This includes turning the pump diode on sufficiently in advance and ramping up the current to produce equal power for the first pulses when the unit is turned on.
[0081] The device also provides a means for calculating and/or storing the desired pump diode current setting as a function of system pulse width and repetition rate, such that the energy of the output pulse is maintained at a desired value as the pulse width and repetition rate are varied.
[0082] A device in accordance with an embodiment of the invention also provides a means for calculating and storing the appropriate pump diode temperature setting as a function of the pump diode current setting, such that the emission wavelength of the pump diode is maintained at a wavelength that provides maximum absorption of the pump diode energy by the fiber amplifier medium as the pump diode current is varied.
[0083] Means are also provided to monitor the repetition rate of the injected pulses into the amplifier system, to compare it to the predetermined repetition rate, and if lower than this repetition rate, to disable or reduce the current to the amplifier pump diode to prevent it from being damaged.
[0084] The exemplary device discussed above also provides a means for comparing the amplitude of the pulse being injected into the fiber amplifier with a predetermined minimum amplitude value and if lower than this predetermined minimum, a means to disable or reduce the current to the amplifier pump diode to prevent it from being damaged. A device in accordance with an embodiment of the invention also provides a means of selecting and attenuating the seed pulses such that the amplified output pulses are of uniform energy.
[0085] It is an even further object of the invention to monitor the repetition rate of the oscillator and to provide a means for calculating the required down counter divide ratio needed to obtain a lower repetition rate.
[0086] It is also an object of the invention to synchronize the oscillator with an external reference signal. It is also an object of the invention to vary this external reference in frequency, and have the oscillator repetition rate vary accordingly.
[0087] It is an even further object of the invention to vary the external reference in frequency, and have the oscillator repetition rate vary accordingly, and also have the down counted repetition rate vary accordingly. However, this variation will be of a limited range compared to an all fiber system due to the operation repetition rate of a regenerative amplifier.
[0088] Finally, these regenerative amplifier systems will be utilized in many cases for micromachining. Improvements for FPCA systems have been developed that are unique for a fiber seed source. Ser. No. 10/813,389 (incorporated by reference herein), describes the benefit for changing the pulse shapes that allow the change of the material processing properties of that laser. These methods include allowing the addition of heat by the addition of longer pulses. The physical means for changing these pulse shapes and building a all fiber chirped pulse amplification system suitable for material processing is described Ser. No. 10/813,269 (incorporated by reference herein). As is mentioned in Ser. No. 10/813,269 some of these changes in the seed source for a fiber chirped pulse amplification systems will also be suitable for regenerative amplifier systems. Herein further methods of obtaining various pulse changes are described.
[0089] The invention thus provides methods of materials processing using bursts of laser light comprised of ultrashort pulses in the femtosecond, picosecond and nanosecond ranges, wherein parameters of the pulses comprising the burst, such as pulse width, pulse separation duration, pulse energy, wavelength and polarization, are manipulated to induce desirable properties in the processed material.
[0090] While a precise and controlled removal of material is achieved using ultrashort pulses, there are situations when having a small amount of thermal effect retained by the material from the previous pulse prior to being irradiated by a subsequent ultrashort pulse is beneficial. In addition, it is well known that the properties of most materials have some dependence on temperature. For example, the absorption of light by silicon is very dependent on temperature. Hence, heating such a target material can help initiate the ablation process at lower threshold fluence and may produce a smoother surface. In general, the thermal and physical effect or any change in structure caused by the prior pulse influences the laser matter interaction with the next pulse.
[0091] The ablation threshold energy density, as a function of pulse width, can vary significantly from the square root of t as pulse widths enter the femtosecond range. These ultrashort pulses can be used to micro-machine cleanly without causing significant heat. These ultrashort pulses also have deterministic thresholds compared to the statistical thresholds of longer pulses.
[0092] The present invention may be used in micro-machining with bursts of pulses having pulse shapes that cannot be quantified by a single pulse width in order to describe their micro-machining properties. For example, a burst comprises a 100 femtosecond pulse and a one nanosecond pulse, where the one nanosecond pulse contains ninety percent of the energy and the 100 femtosecond pulse contains ten percent of the energy. The threshold for ablation of gold is a little over 0.3 J/cm 2 for the 100 femtosecond pulse and 3.0 J/cm 2 for the one nanosecond pulse. Thus, if the burst is focused to output 0.3 J/cm 2 , then ablation will occur during the 100 femtosecond pulse, and not during the one nanosecond pulse. If the one nanosecond pulse impinges upon the surface first, it will have no affect while the 100 femtosecond pulse will ablate. Thus, the one nanosecond predominant pulse will not leave a heat affected zone. However, if the 100 femtosecond pulse is right before the one nanosecond pulse, then the 100 femtosecond pulse will change the absorption properties of the material so the one nanosecond pulse will also interact with the material. In this case, the ablation process would be predominantly heat related. If the one nanosecond pulse is increased to 100 nanoseconds, then the pulse energy content in the long pulse can be increased by ten-fold but the threshold is still determined by the ultrashort pulse and remains fixed even with one percent of the total energy in the ultrafast pulse.
[0093] Thus, in one embodiment of the present invention, the long pulse is before the ultrafast pulse if the pulse repetition rate is substantially greater than or equal 100 kilohertz. In another embodiment of the present invention, a portion of the long pulse follows after the ultrafast pulse, and adding a pedestal on the short pulse can create the long pulse. Micro-machining can be accomplished with an ultrashort pulse, where substantial energy is in a long pulse pedestal (>ten picoseconds) and where the long pulse pedestal adds a thermal machining mechanism.
[0094] The present invention can perform laser machining on material using a burst of ultrashort laser pulses and tailors the pulse width, pulse separation duration, wavelength and polarization to maximize the positive effect of thermal and physical changes achieved by the previous pulse on the laser matter interaction in a burst-machining mode. Better processing results can be achieved by manipulating the pulse width, the pulse separation duration and the pulse energies of pulses within a burst. The wavelength and polarization of a laser beam also strongly affect the absorption of the laser beam, and have to be varied pulse-to-pulse in a burst in order to produce maximum laser-matter interaction.
[0095] Besides the methods of manipulating laser beam parameters described above to achieve desired results, the present invention also includes methods to achieve the thermal and physical enhancement of a material during laser processing. In an embodiment of the present invention, the background light (commonly referred to as Amplified Spontaneous Emission (ASE)) is controlled to provide a constant source of energy for achieving thermal and physical changes to enhance the machining by individual ultrashort pulses. ASE is often emitted simultaneously and co-linearly with the ultrashort pulse from an amplified fiber laser. There are a number of ways to change the ASE ratio in the laser. Examples are changing the ultrashort pulse input energy into the amplifier, changing its center wavelength or changing the diode pump power to the amplifier. Another means more variable is within the compressor of the laser. As disclosed in application Ser. No. 10/813,163 the spectral output of the ASE can be designed to be at a different wavelength then that of the ultrashort pulse. Thus, in the compressor, where the spectral components are physically separated, a component can be placed to block or partially block the ASE, as disclosed in application Ser. No. 10/813,163. The ratio between the ASE and the ultrashort pulse energy can be controlled to vary the amount of preheating applied to the target material. In another embodiment of the invention, a pedestal of an ultrashort pulse is controlled. The pedestal is similar to a superimposed long-pulse with lower amplitude.
[0096] The invention is based on the interaction with a material of laser pulses of different pulse widths, pulse separation duration, energy, wavelength and polarization in a burst mode. The positive aspects of pulses having different pulse widths, pulse separation duration, energies, wavelengths and polarization are utilized, and a negative aspect of one pulse complements a positive aspect of another pulse. The coupling of laser energy during interaction of successive laser pulses with a material induces various thermal, physical and chemical couplings. The induced coupling involves microscopic change of electronic structure, phase transition, structural disintegration and/or other physical changes. For example, pulses with different pulse widths in a burst induce coupling that is different from a burst having pulses with the same pulse width.
[0097] An aspect of the invention provides a method of materials processing using laser light. The method comprises applying bursts of laser light to a target area of a material at a predetermined repetition rate. Preferably, the burst repetition rate is large enough for multipulse pulses generated within the round trip time of the regenerative amplifier, although lower repetition rates can be used. The burst of laser light comprises a first pulse and a second pulse of laser light displaced in time, although more pulses could be used in the burst as necessary. The first pulse has a first pulse width and the second pulse has a second pulse width, and predetermined parameters of the first pulse are selected to induce a change in a selected property of the processed material. The second pulse has a second pulse width, and predetermined parameters of the second pulse are selected based upon the property change induced by the first pulse. The first pulse width is generally in the nanosecond range, and the second pulse width is generally in the picosecond to femtosecond range. However, as stated previously it can be reversed. Predetermined parameters include pulse energy, pulse wavelength, pulse separation duration and pulse polarization vector. These parameters of the first and second pulses are controlled as well to machine the target area of the processed material.
[0098] A still further aspect of the present invention provides a method of materials processing that is similar to the previous aspect, except that the first and second pulses of the burst of laser light are overlapped in time, instead of being displaced in time. More pulses could be used in the burst as necessary. The first pulse has a first pulse width and the second pulse has a second pulse width, and the first pulse width can be greater than the second pulse width. The first pulse has a first pulse width and predetermined parameters of the first pulse are selected to induce a change in a selected property of the processed material. The second pulse has a second pulse width, and predetermined parameters of the second pulse are selected on based upon the property change induced by the first pulse. The first pulse width is generally in the nanosecond range, and the second pulse width is generally in the picosecond to femtosecond range. Predetermined parameters include pulse energy, pulse wavelength, pulse separation duration and pulse polarization vector which are controlled as well to machine the target area of the processed material. In addition, the second pulse may include a pedestal to facilitate thermally heating the processed material.
[0099] In yet another aspect of the present invention, an apparatus for generating optical pulses, wherein each pulse may have individualized characteristics, is provided. The apparatus comprises a laser means for generating the bursts of pulses, a control means that controls the laser means and a beam manipulation means for monitoring the pulse width, wavelength, repetition rate, polarization and/or temporal delay characteristics of the pulses comprising the pulse bursts. The apparatus generates feedback data based on the measured pulse width, wavelength, repetition rate, polarization and/or temporal delay characteristics for the control means. In one embodiment of the present invention, the laser means may comprise a fiber amplifier that uses stretcher gratings and compressor gratings. The beam manipulation means can comprise a variety of devices, e.g., an optical gating device that measures the pulse duration of the laser pulses, a power meter that measures the power of the laser pulses output from the laser means or a photodiode that measures a repetition rate of the laser pulses. Another beam manipulation means optically converts the fundamental frequency of a percentage of the generated laser pulses to one or more other optical frequencies, and includes at least one optical member that converts a portion of the fundamental of the laser pulses into at least one higher order harmonic signal. The optical member device may comprise a non-linear crystal device with a controller that controls the crystal's orientation. Preferably, the means for converting an optical frequency includes a spectrometer that measures predetermined parameters of pulses output from the non-linear crystal device and generates feedback for the control means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0100] The accompanying drawings, which are incorporated in and constitute a part of this specification illustrate embodiments of the invention and, together with the description, serve to explain the aspects, advantages and principles of the invention. In the drawings,
[0101] FIG. 1 is a block diagram showing the basic components of the present invention.
[0102] FIG. 2 is an illustration of a modular, compact, tunable system for generating high peak and high average power ultrashort laser pulses in accordance with the present invention;
[0103] FIG. 3 is an illustration of an embodiment of a Seed Module (SM) for use in the present invention;
[0104] FIG. 4 is a diagram graphically illustrating the relationship between the average frequency-doubled power and wavelength which are output at a given range of input power according to one embodiment of the present invention.
[0105] FIG. 5 is an illustration of an embodiment of a Pulse Compressor Module (PCM) for use with the present invention;
[0106] FIG. 6 is an illustration of an embodiment of a Pulse Stretcher Module (PSM) for use with the present invention;
[0107] FIG. 7 is an illustration of a second embodiment of a Seed Module (SM) for use with the present invention;
[0108] FIG. 8 is an illustration of a third embodiment of a Seed Module (SM) for use with the present invention;
[0109] FIG. 9 is an illustration of a fourth embodiment of a Seed Module (SM) for use with the present invention;
[0110] FIG. 10 is an illustration of a fifth embodiment of a Seed Module (SM) for use with the present invention;
[0111] FIG. 11 is an illustration of an embodiment of the present invention in which a Fiber Delivery Module (FDM) is added to the embodiment of the invention shown in FIG. 1 ;
[0112] FIG. 12 is an illustration of an embodiment of a Fiber Delivery Module (FDM) for use with the present invention;
[0113] FIG. 13 is an illustration of a second embodiment of a Pulse Stretcher Module (PSM) for use with the present invention;
[0114] FIG. 14 is an illustration of a third embodiment of a Pulse Stretcher Module (PSM) for use with the present invention;
[0115] FIG. 15 is an illustration of an embodiment of the present invention in which pulse picking elements and additional amplification stages are added.
[0116] FIG. 16 is an illustration of another embodiment of the present invention where a fiber amplifier is operated with at least one forward and one backward pass, in combination with optical modulators such as pulse picking elements.
[0117] FIG. 17 is a diagram of a cladding pumped fiber cavity design according to a first embodiment of the invention.
[0118] FIG. 18 a is a diagram of a saturable absorber mirror according to an embodiment of the invention.
[0119] FIG. 18 b is a diagram of a saturable absorber minor according to an alternative embodiment of the invention.
[0120] FIG. 19 is a diagram of the proton concentration as a function of depth obtained after proton implantation into a saturable semiconductor film.
[0121] FIG. 20 is a diagram of the measured bi-temporal reflectivity modulation obtained in a semiconductor saturable mirror produced by ion-implantation with selective depth penetration.
[0122] FIG. 21 a is a diagram of a scheme for coupling a saturable absorber minor to a fiber end according to an embodiment of the invention.
[0123] FIG. 21 b is a diagram of a scheme for coupling a saturable absorber mirror to a fiber end according to an alternative embodiment of the invention.
[0124] FIG. 22 is a diagram for increasing the optical bandwidth of a fiber laser according to an embodiment of the invention.
[0125] FIG. 23 is a diagram of a core pumped fiber cavity design according to an embodiment of the invention.
[0126] FIG. 24 is a diagram of a core pumped fiber cavity design using intra-cavity wavelength division multiplexers and output couplers according to an embodiment of the invention.
[0127] FIG. 25 is a diagram of a core pumped fiber cavity design using intra-cavity wavelength division multiplexers and a butt-coupled fiber pig-tail for output coupling according to an embodiment of the invention.
[0128] FIG. 26 is a diagram of a cladding pumped fiber cavity design using an intra-cavity output coupler according to an embodiment of the invention.
[0129] FIG. 27 is a diagram of a cladding pumped fiber cavity design using intra-cavity fiber output couplers according to an embodiment of the invention.
[0130] FIG. 28 a is a diagram of a passively modelocked fiber laser based on concatenated sections of polarization maintaining and non-polarization maintaining fiber sections according to an embodiment of this invention.
[0131] FIG. 28 b is a diagram of a passively modelocked fiber laser based on concatenated sections of long polarization maintaining fiber sections according to an embodiment of this invention.
[0132] FIG. 28 c is a diagram of a passively modelocked fiber laser based on short concatenated sections of polarization maintaining fiber and additional sections of all-fiber polarizer according to an embodiment of this invention.
[0133] FIG. 29 is a diagram of a dispersion compensated fiber laser cavity according to an embodiment of this invention.
[0134] FIG. 30 is a diagram of a dispersion compensated fiber laser cavity according to an alternative embodiment of this invention, including means for additional spectral broadening of the fiber laser output.
[0135] FIG. 31 is a diagram of a design based on a fiber based MOPA having the fewest bulk optical components, according to a further embodiment.
[0136] FIG. 32 is an embodiment which includes monitoring electronics and feedback control of a fiber based pulse source.
[0137] FIG. 33 a illustrates a module usable for polarization correction or as variable attenuation in a fiber based laser system.
[0138] FIG. 33 b illustrates a particularly preferred embodiment for a fiber solid-state regenerative amplifier system.
[0139] FIG. 34 shows a source of ultra-fast pulses based upon a microchip laser.
[0140] FIG. 35 illustrates a source based on a DFB laser and a lithium niobate pulse generator.
[0141] FIG. 36 illustrates a system allowing independent control of higher order dispersion and self-phase modulation.
[0142] FIG. 37 illustrates an algorithm for a control system for ensuring mode-locking.
[0143] FIG. 38 illustrates an embodiment enabling the gain bandwidth of the regenerative amplifier to be easily matched to the fiber amplifier system.
[0144] FIG. 39 illustrates a generic scheme for the amplification of the output of a FCPA system in a bulk optical amplifier.
[0145] FIG. 40 illustrates an embodiment employing a series of chirped gratings operating on different portions of the spectrum, for elongating the pulse envelope.
[0146] FIGS. 41 and 42 show a laser diode-based multiple pulse source, and a laser system including this source.
[0147] FIGS. 43 a - 43 c show outputs of the pulse source of FIG. 41 in graphic form.
[0148] FIG. 44 illustrates a wavelength router scheme usable with the embodiment of FIG. 41 ; and
[0149] FIG. 45 illustrates a fiber splitter arrangement useable in the embodiment of FIG. 41 .
DETAILED DESCRIPTION OF THE INVENTION
[0150] A generalized illustration of the system of the invention is shown in FIG. 1 . The pulses are generated in a short pulse source. 11 . These are coupled into a pulse conditioner 12 for spectral narrowing, broadening or shaping, wavelength converting, temporal pulse compression or stretching, pulse attenuation and/or lowering the repetition rate of the pulse train. The pulses are subsequently coupled into an Yb: or Nd: fiber amplifier 13 . Pulse stretcher 14 provides further pulse stretching before the amplification in the regenerative amplifier 15 that is based on an Nd: or Yb: doped solid-state laser material. The compressor 16 compresses the pulse back to near transform limit. The six basic subsystems described here are each subject to various implementations, as is described in the subsequent embodiments.
[0151] A generalized illustration of one embodiment of the short pulse source 11 is shown in FIG. 2 . The pulses generated in a laser seed source 1 (seed module; SM) are coupled into a pulse stretcher module 2 (PSM), where they are dispersively stretched in time. The stretched pulses are subsequently coupled into the fundamental mode of a cladding-pumped Yb fiber amplifier 3 (amplifier module, AM 1 ), where the pulses are amplified by at least a factor of 10. Finally, the pulses are coupled into a pulse compressor module 4 (PCM), where they are temporally compressed back to approximately the bandwidth limit.
[0152] The embodiment shown in FIG. 2 is modular and four sub-systems; the SM 1 , PSM 2 , AM 1 3 and PCM 4 . The sub-systems can be used independently as well as in different configurations, as described in the alternative embodiments.
[0153] In the following, discussion is restricted to the SM-PSM-AM 1 -PCM system. The SM 1 preferably comprises a femtosecond pulse source (seed source 5 ). The PSM preferably comprises a length of fiber 6 , where coupling between the SM and the PSM is preferably obtained by fusion splicing. The output of the PSM is preferably injected into the fundamental mode of the Yb amplifier 7 inside the AM 1 module 3 . Coupling can be performed by fusion splicing, a fiber coupler or a bulk-optic imaging system between PSM 2 and the fiber amplifier 7 . All fibers are preferably selected to be polarization maintaining. The PCM 4 is preferably a dispersive delay line constructed from one or two bulk optic diffraction gratings for reasons of compactness. Alternatively, a number of bulk optic prisms and Bragg gratings can be used inside the PCM 4 . Coupling to the PCM 4 can be performed by a bulk optic lens system as represented by the single lens 8 in FIG. 2 . In the case of a PCM that contains fiber Bragg gratings, a fiber pig-tail can be used for coupling to the PCM.
[0154] As an example of a femtosecond laser seed source, a Raman-shifted, frequency-doubled Er fiber laser is shown within an SM 1 b in FIG. 3 . The femtosecond fiber laser 9 can be a commercial high energy soliton source (IMRA America, Inc., Femtolite B-60™) delivering ≈200 fs pulses at a wavelength of 1.57 μm and a pulse energy of 1 nJ at a repetition rate of 50 MHz.
[0155] For optimum Raman-shifting from 1.5 μm to the 2.1 μm wavelength region, a reduction in the core diameter (tapering) along the length of the polarization maintaining Raman-shifting fiber 10 is introduced. A reduction of the core diameter is required to keep the 2nd order dispersion in the Raman-shifter close to zero (but negative) in the whole wavelength range from 1.5 to 2.1 μm. By keeping the absolute value of the 2nd order dispersion small, the pulse width inside the Raman shifter is minimized, which leads to a maximization of the Raman frequency shift (J. P. Gordon, “Theory of the Soliton Self-frequency Shift,” Opt. Lett., 11, 662 (1986)). Without tapering, the Raman frequency-shift is typically limited to around 2.00 μm, which even after frequency-doubling is not compatible with the gain bandwidth of Yb fiber amplifiers.
[0156] In this particular example, a two-stage Raman shifter 10 consisting of 30 and 3 m lengths of silica ‘Raman’ fiber (single-mode at 1.56 μm) with core diameters of 6 and 4 μm respectively, was implemented. Due to the onset of the infrared absorption edge of silica at 2.0 μm, it is beneficial to increase the rate of tapering towards the end of the Raman shifter 10 . In the present example, conversion efficiencies up to 25% from 1.57 μm to 2.10 μm were obtained. Even better conversion efficiencies can be obtained by using a larger number of fibers with smoothly varying core diameter, or by implementing a single tapered fiber with smoothly varying core diameter.
[0157] Frequency-conversion of the Raman-shifted pulses to the 1.05 μm region can be performed by a length of periodically poled LiNbO3 (PPLN) crystal 11 with an appropriately selected poling period. (Although throughout this specification, the preferable material for frequency conversion is indicated as PPLN, it should be understood that other periodically-poled ferroelectric optical materials such as PP lithium tantalate, PP MgO:LiNbO 3 , PP KTP, or other periodically poled crystals of the KTP isomorph family can also be advantageously used.) Coupling with the PPLN crystal 11 occurs through the use of a lens system, represented in FIG. 3 by lenses 12 . The output of the PPLN crystal 11 is coupled by lenses 12 into output fiber 13 . Conversion efficiencies as high as 16% can so be obtained for frequency-doubling of 2.1 μm resulting in a pulse energy up to 40 pJ in the 1 μm wavelength region. The spectral width of the frequency-converted pulses can be selected by an appropriate choice of the length of the PPLN crystal 11 ; for example a 13 mm long PPLN crystal produces a bandwidth of 2 nm in the 1.05 μm region corresponding to a pulse width of around 800 fs. The generated pulse width is approximately proportional to the PPLN crystal length, i.e., a frequency converted pulse with a 400 fs pulse width requires a PPLN length of 6.5 mm. This pulse width scaling can be continued until the frequency-converted pulse width reaches around 100 fs, where the limited pulse width of 100 fs of the Raman-shifted pulses limits further pulse width reduction.
[0158] In addition, when the frequency-converted pulse width is substantially longer than the pulse width of the Raman-shifted pulses, the wide bandwidth of the Raman-pulses can be exploited to allow for wavelength-tuning of the frequency-converted pulses, i.e., efficient frequency conversion can be obtained for pulses ranging in frequency from 2(ω 1 −δω) to 2(ω 1 +δω), where 2δω is the spectral width at half maximum of the spectrum of the Raman-shifted pulses. Continuous wavelength tuning here is simply performed by tuning the temperature of the frequency-conversion crystal 11 .
[0159] The amplified noise of the Raman-shifter, PPLN-crystal combination is minimized as follows. Self-limiting Raman-shifting of the Er fiber laser pulse source can be used by extending the Raman shift out to larger than 2 μm in silica-based optical fiber. For wavelengths longer than 2 μm, the infrared absorption edge of silica starts to significantly attenuate the pulses, leading to a limitation of the Raman shift and a reduction in amplitude fluctuations, i.e., any increase in pulse energy at 1.5 μm tends to translate to a larger Raman-shift and thus to a greater absorption in the 2 μm wavelength region, which thus stabilizes the amplitude of the Raman-shifted pulses in this region.
[0160] Alternatively, the noise of the nonlinear frequency conversion process can be minimized by implementing self-limiting frequency-doubling, where the center wavelength of the tuning curve of the doubling crystal is shorter than the center wavelength of the Raman-shifted pulses. Again, any increase in pulse energy in the 1.5 μm region translates into a larger Raman-shift, producing a reduced frequency conversion efficiency, and thus the amplitude of the frequency-doubled pulses is stabilized. Therefore a constant frequency-converted power can be obtained for a large variation in input power.
[0161] This is illustrated in FIG. 4 , where the average frequency-converted power in the 1 μm wavelength region as a function of average input power at 1.56 μm is shown. Self-limiting frequency-doubling also ensures that the frequency-shifted wavelength in the 1 μm wavelength region is independent of average input power in the 1.56 μm wavelength region, as also demonstrated in FIG. 4 .
[0162] Several options exist for the PSM 2 . When a length of fiber 6 (stretching fiber) is used as a PSM as shown in FIG. 2 , an appropriate dispersive delay line can then be used in the PCM 4 to obtain near bandwidth-limited pulses from the system. However, when the dispersive delay line in the PCM 4 consists of bulk diffraction gratings 14 as shown in FIG. 5 , a possible problem arises. The ratio of |3 rd /2 nd |-order order dispersion is typically 1-30 times larger in diffraction grating based dispersive delay lines compared to the ratio of apertures operating in the 1 μm wavelength regime, the sign of the third-order dispersion in the fiber is the same as in a grating based dispersive delay line. Thus a fiber stretcher in conjunction with a grating-based stretcher does not typically provide for the compensation of 3 rd - and higher-order dispersion in the system.
[0163] For pulse stretching by more than a factor of 10, the control of third-order and higher-order dispersion becomes important for optimal pulse compression in the PCM 4 . To overcome this problem, the stretcher fiber 6 in the PSM 2 can be replaced with a length of fibers with W-style multi-clad refractive index profiles, i.e., ‘W-fibers’ (B. J. Ainslie et al.) or holey fibers (T. M. Monroe et al., ‘Holey Optical Fibers’ An Efficient Modal Model, J. Lightw. Techn., vol. 17, no. 6, pp. 1093-1102). Both W-fibers and holey fibers allow adjustable values of 2nd, 3rd and higher-order dispersion. Due to the small core size possible in W and holey fibers, larger values of 3rd order dispersion than in standard single-mode fibers can be obtained. The implementation is similar to the one shown in FIG. 1 and is not separately displayed. The advantage of such systems is that the PSM can work purely in transmission, i.e., it avoids the use of dispersive Bragg gratings operating in reflection, and can be spliced into and out of the system for different system configurations.
[0164] An alternative PSM 2 with adjustable values of 2 nd , 3 rd and 4 th order dispersion is shown in FIG. 6 . The PSM 20 a is based on the principle that conventional step-index optical fibers can produce either positive, zero or negative 3rd order dispersion. The highest amount of 3rd order dispersion in a fiber is produced by using its first higher-order mode, the LP 11 mode near cut-off. In FIG. 6 , the 4 th and 3 rd order dispersion of the PSM 20 a is adjusted by using three sections 15 , 16 , 17 of pulse stretching fiber. The 1st stretcher fiber 15 can be a length of fiber with zero 3rd-order and appropriate 4 th -order dispersion. The 1st stretcher fiber 15 is then spliced to the 2 nd stretcher fiber 16 , which is selected to compensate for the 3 rd -order dispersion of the grating compressor as well as the whole chirped-pulse amplification system. To take advantage of the high 3 rd -order dispersion of the LP 11 mode the 1st stretcher fiber 15 is spliced to the 2 nd stretcher fiber 16 with an offset in their respective fiber centers, leading to a predominant excitation of the LP 11 mode in the 2nd stretcher fiber 16 . To maximize the amount of 3rd-order dispersion in the 2nd stretcher fiber 16 , a fiber with a high numerical aperture NA>0.20 is preferred. At the end of the 2nd stretcher fiber 16 , a similar splicing technique is used to transfer the LP 11 mode back to the fundamental mode of the 3 rd stretcher fiber 17 . By an appropriate choice of fibers, the 4th-order dispersion of the whole amplifier compressor can be minimized. The 3 rd stretcher fiber 17 can be short with negligible dispersion.
[0165] The transfer loss of the whole fiber stretcher assembly is at least 25% due to the unavoidable 50% or greater loss incurred by transferring power from the LP 11 mode to the LP 01 mode without the use of optical mode-converters. Any residual energy in the LP 01 mode in the 2nd stretcher fiber can be reflected with an optional reflective fiber grating 18 as shown in FIG. 6 . Due to the large difference in effective index between the fundamental and the next higher-order mode, the grating resonance wavelength varies between 10-40 nm between the two modes, allowing for selective rejection of one mode versus the other for pulses with spectral widths between 10-40 nm.
[0166] The energy loss of the fiber stretcher assembly can be made to be insignificant by turning the 3 rd stretcher fiber 17 into an Yb amplifier. This implementation is not separately shown.
[0167] When 4th-order dispersion is not significant, the 1st stretcher fiber 15 can be omitted. 4 th order dispersion can also be compensated by using a 1st stretcher fiber with non-zero 3 rd order dispersion, as long as the ratio of 3 rd and 4 th order dispersion is different between the 1 st and 2 nd stretcher fiber.
[0168] The Yb-doped fiber inside the AM 1 3 can have an Yb doping level of 2.5 mole % and a length of 5 m. Both single-mode and multi-mode Yb-doped fiber can be used, where the core diameter of the fiber can vary between 1-50 μm; though the fundamental mode should be excited in case of a MM fiber to optimize the spatial quality of the output beam. Depending on the amount of required gain, different lengths of Yb-doped fiber can be used. To generate the highest possible pulse energies, Yb fiber lengths as short as 1 m can be implemented.
[0169] Pulse compression is performed in the PCM 4 . The PCM 4 can contain conventional bulk optic components (such as the bulk diffraction grating pair shown in FIG. 5 ), a single grating compressor, or a number of dispersive prisms or grisms or any other dispersive delay line.
[0170] Alternatively, a fiber or bulk Bragg grating can be used, or a chirped periodically poled crystal. The chirped periodically poled crystal combines the functions of pulse compression and frequency doubling (A. Galvanauskas, et al., ‘Use of chirped quasi-phase matched materials in chirped pulse amplification systems,’ U.S. application Ser. No. 08/822,967, the contents of which are hereby incorporated herein by reference) and operates in transmission providing for a uniquely compact system.
[0171] Other modifications and variations to the invention will be apparent to those skilled in the art from the foregoing disclosure and teachings.
[0172] In particular, the SM 1 can be used as a stand-alone unit to produce near bandwidth limited femtosecond pulses in the frequency range from 1.52-2.2 μm, and after frequency conversion in a nonlinear crystal also in the frequency range from 760 nm to 1.1 μm. The frequency range can be further extended by using a fluoride Raman-shifting fiber or other optical fibers with infrared absorption edges longer than silica. Using this technique wavelengths up to around 3-5 μm can be reached. In conjunction with frequency-doubling, continuous tuning from 760 nm to 5000 nm can be achieved. The pulse power in the 2 μm region can be further enhanced by using Tm or Ho-doped fiber. With such amplifiers, near bandwidth-limited Raman-soliton pulses with pulse energies exceeding 10 nJ can be reached in single-mode fibers in the 2 μm wavelength region. After frequency-doubling, femtosecond pulses with energies of several nJ can be obtained in the 1 μm region without the use of any dispersive pulse compressors. Such pulses can be used as high energy seed pulses for large-core multi-mode Yb amplifiers, which require higher seed pulse energies than single-mode Yb amplifiers to suppress amplified spontaneous emission.
[0173] An example of an ultra-wide tunable fiber source combining an Er-fiber laser pulse source 19 with a silica Raman-shifter 20 , a Tm-doped amplifier 21 and a 2 nd fluoride glass based Raman shifter 22 is shown in the SM 1 c of FIG. 7 . An optional frequency-doubler is not shown for converting into the 900 nm to 1050 nm range. This would be a means for obtaining a high power source in this range. For optimum stability all fibers should be polarization maintaining. As another alternative to the Er-fiber laser pulse source a combination of a diode-laser pulse source with an Er-amplifier can be used; this is not separately shown.
[0174] As yet another alternative for a SM, SM 1 d is shown in FIG. 8 , and contains a frequency-doubled high-power passively mode-locked Er or Er/Yb-fiber oscillator 23 in conjunction with a length of Raman-shifting holey fiber 24 . Here the pulses from the oscillator 23 operating in the 1.55 μm wavelength region are first frequency-doubled using frequency doubler 25 and lens system 26 , and subsequently the frequency-doubled pulses are Raman-shifted in a length of holey fiber 24 that provides soliton supporting dispersion for wavelengths longer than 750 nm or at least longer than 810 nm. By amplifying the Raman-shifted pulses in the 1 μm wavelength regime or in the 1.3, 1.5, or 2 μm wavelength regime and by selecting different designs of Raman-shifting fibers, a continuously tunable source operating in the wavelength region from around 750 nm to 5000 nm can be constructed. The design of such a source with a number of attached amplifiers 27 is also shown in FIG. 8 .
[0175] For optimum Raman self-frequency shift, the holey fiber dispersion should be optimized as a function of wavelength. The absolute value of the 3rd order dispersion of the holey fiber should be less than or equal to the absolute value of the 3rd order material dispersion of silica. This will help ensure that the absolute value of the 2nd order dispersion remains small over a substantial portion of the wavelength tuning range. Moreover the value of the 2nd order dispersion should be negative, and a 2nd order dispersion zero should be within 300 nm in wavelength to the seed input wavelength.
[0176] As yet another alternative for a seed source for an Yb amplifier, anti-Stokes generation in a length of anti-Stokes fiber can be used. After anti-Stokes generation, additional lengths of fiber amplifiers and Raman-shifters can be used to construct a widely wavelength-tunable source. A generic configuration is similar to the one shown in FIG. 8 , where the frequency-doubling means 25 are omitted and the Raman-shifter means 24 are replaced with an anti-Stokes generation means. For example, to effectively generate light in the 1.05 μm wavelength regime in an anti-Stokes generation means using an Er fiber laser seed source operating at 1.55 μm, an anti-Stokes generation means in the form of an optical fiber with small core diameter and a low value of 3 rd order dispersion is optimum. A low value of 3 rd order dispersion is here defined as a value of 3 rd order dispersion smaller in comparison to the value of 3 rd order dispersion in a standard telecommunication fiber for the 1.55 wavelength region. Moreover, the value of the 2 nd order dispersion in the anti-Stokes fiber should be negative.
[0177] As yet another alternative seed-source for an Yb amplifier, a passively modelocked Yb or Nd fiber laser can be used inside the SM. Preferably an Yb soliton oscillator operating in the negative dispersion regime can be used. To construct an Yb soliton oscillator, negative cavity dispersion can be introduced into the cavity by an appropriately chirped fiber grating 29 , which is connected to output fiber 36 as shown in FIG. 9 ; alternatively, negative dispersion fiber such as holey fiber (T. Monroe et al.) can be used in the Yb soliton laser cavity. A SM incorporating such an arrangement is shown as SM 1 e in FIG. 9 . Here the Yb fiber 30 can be polarization maintaining and a polarizer 31 can be incorporated to select oscillation along one axis of the fiber (coupling being accomplished with lenses 32 ). For simplicity, the Yb fiber 30 can be cladding pumped from the side as shown in FIG. 9 . However, a passively modelocked Yb fiber laser incorporating conventional single-mode fiber with conventional pumping through a WDM can also be used. Such an arrangement is not separately shown. In FIG. 9 , SA 28 is used to induce the formation of short optical pulses. The grating 35 is used for dispersive control, and as an intra-cavity mirror. The pump diode 33 delivers pump light through V-groove 34 .
[0178] An arrangement incorporating a holey fiber can be nearly identical to the system displayed in FIG. 9 , where an additional length of holey fiber is spliced anywhere into the cavity. In the case of incorporating a holey fiber, the fiber Bragg grating does not need to have negative dispersion; equally the Bragg grating can be replaced with a dielectric mirror.
[0179] Most straight-forward to implement, however, is an Yb oscillator operating in the positive dispersion regime, which does not require any special cavity components such as negative dispersion fiber Bragg gratings or holey fiber to control the cavity dispersion. In conjunction with a ‘parabolic’ Yb amplifier (or ordinary Yb amplifier), a very compact seed source for a high-power Yb amplifier system can be obtained. Such a Yb oscillator with an Yb amplifier 40 is shown in FIG. 10 , where preferably the Yb amplifier 40 is a ‘parabolic’ Yb amplifier as discussed below. Elements which are identical to those in FIG. 9 are identically numbered.
[0180] The SM 1 f in FIG. 10 comprises a side-pumped Yb amplifier 40 as described with respect to FIG. 9 , though any other pumping arrangement could also be implemented. The Yb fiber 44 is assumed to be polarization maintaining and a polarizer 31 is inserted to select a single polarization state. The fiber Bragg grating 37 has a reflection bandwidth small compared to the gain bandwidth of Yb and ensures the oscillation of pulses with a bandwidth small compared to the gain bandwidth of Yb. The Bragg grating 37 can be chirped or unchirped. In the case of an unchirped Bragg grating, the pulses oscillating inside the Yb oscillator are positively chirped. Pulse generation or passive modelocking inside the Yb oscillator is initiated by the saturable absorber 28 . The optical filter 39 is optional and further restricts the bandwidth of the pulses launched into the Yb amplifier 40 .
[0181] To optimize the formation of parabolic pulses inside the Yb amplifier 40 inside the SM 1 f , the input pulses should have a bandwidth small compared to the gain bandwidth of Yb; also the input pulse width to the Yb amplifier 40 should be small compared to the output pulse width and the gain of the Yb amplifier 40 should be as high as possible, i.e., larger than 10. Also, gain saturation inside the Yb amplifier 40 should be small.
[0182] As an example of a parabolic amplifier a Yb amplifier of 5 m in length can be used. Parabolic pulse formation is ensured by using a seed source with a pulse width of around 0.2-1 ps and a spectral bandwidth on the order of 3-8 nm. Parabolic pulse formation broadens the bandwidth of the seed source to around 20-30 nm inside the Yb amplifier 40 , whereas the output pulses are broadened to around 2-3 ps. Since the chirp inside parabolic pulses is highly linear, after-compression pulse widths on the order of 100 fs can be obtained. Whereas standard ultrafast solid state amplifiers can tolerate a nonlinear phase shift from self-phase modulation only as large as pi (as well known in the state of the art), a parabolic pulse fiber amplifier can tolerate a nonlinear phase shift as large as 10*pi and higher. For simplicity, we thus refer to a large gain Yb amplifier as a parabolic amplifier. Parabolic amplifiers obey simple scaling laws and allow for the generation of parabolic pulses with spectral bandwidths as small as 1 nm or smaller by an appropriate increase of the amplifier length. For example, a parabolic pulse with a spectral bandwidth of around 2 nm can be generated using a parabolic amplifier length of around 100 m.
[0183] Since a parabolic pulse can tolerate large values of self-modulation and a large amount of spectral broadening without incurring any pulse break up, the peak power capability of a parabolic amplifier can be greatly enhanced compared to a standard amplifier. This may be explained as follows. The time dependent phase delay Φ nl (t) incurred by self-phase modulation in an optical fiber of length L is proportional to peak power, i.e.
[0000] Φ nl ( t )=γ P ( t ) L,
[0184] where P(t) is the time dependent peak power inside the optical pulse. The frequency modulation is given by the derivative of the phase modulation, i.e., δω=γL[∂P(t)/∂t]. For a pulse with a parabolic pulse profile P(t)=P 0 [1−(t/t 0 ) 2 ], where (−t 0 <t<t 0 ), the frequency modulation is linear. It may then be shown that indeed the pulse profile also stays parabolic, thus allowing the propagation of large peak powers with only a resultant linear frequency modulation and the generation of a linear pulse chirp.
[0185] The chirped pulses generated with the Yb amplifier 40 can be compressed using a diffraction grating compressor as shown in FIG. 5 . Alternatively, the pulses can be left chirped and compensated with the compressor after the regenerative amplifier.
[0186] In addition to the passively modelocked Yb fiber laser 44 shown in FIG. 10 , alternative sources could also be used to seed the Yb amplifier. These alternative sources can comprise Raman-shifted Er or Er/Yb fiber lasers, frequency-shifted Tm or Ho fiber lasers and also diode laser pulse sources. These alternative implementations are not separately shown.
[0187] In FIG. 11 a fiber delivery module (FDM) 45 is added to the basic system shown in FIG. 2 . The PSM 2 is omitted in this case; however, to expand the peak power capability of the amplifier module a PSM 2 can be included when required. The Yb amplifier 7 shown in FIG. 11 can be operated both in the non-parabolic or the parabolic regime.
[0188] In its simplest configuration, the FDM 45 consists of a length of optical fiber 46 (the delivery fiber). For a parabolic amplifier, the delivery fiber 46 can be directly spliced to the Yb amplifier 7 without incurring any loss in pulse quality. Rather, due to the parabolic pulse profile, even for large amounts of self-phase modulation, an approximately linear chirp is added to the pulse allowing for further pulse compression with the PCM 4 . The PCM 4 can be integrated with the FDM 45 by using a small-size version of the bulk diffraction grating compressor 14 shown in FIG. 5 in conjunction with a delivery fiber. In this case the delivery fiber in conjunction with an appropriate collimating lens would replace the input shown in FIG. 5 . A separate drawing of such an implementation is not shown. However, the use of the PCM 4 is optional and can for example be omitted, if chirped output pulses are required from the system. In conjunction with a PCM 4 , the system described in FIG. 11 constitutes a derivative of a chirped pulse amplification system, where self-phase modulation as well as gain is added while the pulse is dispersively broadened in time. The addition of self-phase modulation in conventional chirped pulse amplification systems typically leads to significant pulse distortions after pulse compression. The use of parabolic pulses overcomes this limitation.
[0189] To obtain pulse widths shorter than 50 fs, the control of third order and higher-order dispersion in a FDM module or in an optional PSM becomes significant. The control of higher-order dispersion with a PSM was already discussed with reference to FIGS. 2 and 6 ; the control of higher-order dispersion in a FDM is very similar and discussed with an exemplary embodiment of the FDM 45 a shown in FIG. 12 . Just as in FIG. 2 , the large third-order dispersion of a W-fiber can be used to compensate for the third-order dispersion of a bulk PCM 4 . Just as in FIG. 6 , by using fibers 15 , 16 , 17 with different values for higher-order dispersion in the FDM, the higher order dispersion of the whole system including a PCM 4 consisting of bulk diffraction gratings may be compensated.
[0190] Alternative embodiments of PSMs are shown in FIGS. 13 and 14 , which are also of practical value as they allow the use of commercially available linearly chirped fiber Bragg gratings in the PSM, while compensating for higher-order dispersion of a whole chirped-pulse amplification system comprising PSM as well as PCM. As another alternative, nonlinearly chirped fiber Bragg gratings can also be used in the PSM to compensate for the dispersion of the PCM. Such an arrangement is not separately shown.
[0191] Alternatively, the pulses can be left chirped and compensated with the compressor after the regenerative amplifier. This would mean not utilizing the PCM. This design would place additional design challenges on the dispersion correction in the PSM.
[0192] To avoid the use of W-fibers or the LP 11 mode in the PSM, an alternative embodiment of a PSM as shown in FIG. 13 is shown as PSM 2 b . Here a negatively linearly chirped Bragg grating 47 is used in conjunction with a single-mode stretcher fiber 48 with negative third-order dispersion and circulator 49 . The introduction of the negative linearly chirped Bragg grating increases the ratio of (3 rd /2 nd )-order dispersion in the PSM 2 b , allowing for the compensation of the high value of 3 rd order dispersion in the PCM 4 , when a bulk diffraction grating compressor is used. The PSM 2 b can also contain W-fibers in conjunction with a linearly chirped fiber Bragg grating to further improve the flexibility of the PSM.
[0193] As yet another alternative embodiment of a PSM for the compensation of higher-order dispersion the arrangement in FIG. 14 is shown as PSM 2 c , comprising a positively linearly chirped fiber Bragg grating 50 , circulator 49 and another fiber transmission grating 51 . Here the positively linearly chirped fiber Bragg grating 50 produces positive 2nd order dispersion and the other fiber transmission grating 51 produces an appropriate amount of additional 2 nd 3 rd and 4 th order dispersion, to compensate for the linear and higher order dispersion inside the PCM module. More than one fiber transmission grating or fiber Bragg grating can be used to obtain the appropriate value of 3 rd and 4 th and possibly even higher-order dispersion.
[0194] To increase the amplified pulse energy from an Yb amplifier to higher pulse energies, pulse picking elements and further amplification stages can be implemented as shown in FIG. 15 . In this case, pulse pickers 52 are inserted in between the PSM 2 and the 1 st amplifier module AM 13 a , as well as between the 1st amplifier stage AM 13 a and 2nd amplifier stage AM 2 3 b . Any number of amplifiers and pulse pickers can be used to obtain the highest possible output powers, where the final amplifier stages preferably consist of multi-mode fibers. To obtain a diffraction limited output the fundamental mode in these multi-mode amplifiers is selectively excited and guided using well-known techniques (M. E. Fermann et al., U.S. Pat. No. 5,818,630 and U.S. application Ser. No. 10/424,220) (both incorporated by reference herein). The pulse pickers 52 are typically chosen to consist of optical modulators such as acousto-optic or electro-optic modulators. The pulse pickers 52 down-count the repetition rate of the pulses emerging from the SM 1 by a given value (e.g. from 50 MHz to 5 KHz), and thus allow the generation of very high pulse energies while the average power remains small. Alternatively, directly switchable semiconductor lasers could also be used to fix the repetition rate of the system at an arbitrary value. Further, the pulse pickers 52 inserted in later amplifier stages also suppress the build up of amplified spontaneous emission in the amplifiers allowing for a concentration of the output power in high-energy ultra-short pulses. The amplification stages are compatible with PSMs and PCMs as discussed before; where the dispersion of the whole system can be minimized to obtain the shortest possible pulses at the output of the system.
[0195] Amplifier module AM 1 3 a can be designed as a parabolic amplifier producing pulses with a parabolic spectrum. Equally, the parabolic pulses from AM 1 3 a can be transformed into pulses with a parabolic pulse spectrum in a subsequent length of pulse-shaping or pulse stretching fiber 53 as also shown in FIG. 15 , where the interaction of self-phase modulation and positive dispersion performs this transformation. This may be understood, since a chirped pulse with a parabolic pulse profile can evolve asymptotically into a parabolic pulse with a parabolic spectrum in a length of fiber. The parabolic pulse shape maximizes the amount of tolerable self-phase modulation in the subsequent amplification stages, which in turn minimizes the amount of dispersive pulse stretching and compression required in the PSM 2 and PCM 4 . Equally, parabolic pulse shapes allow the toleration of significant amounts of self-phase modulation in the PSM 2 without significant pulse distortions.
[0196] Once the pulses are stretched, the detrimental influence of self-phase modulation in subsequent amplifiers can be minimized by using flat-top pulse shapes. A flat-top pulse shape can be produced by inserting an optional amplitude filter 54 as shown in FIG. 15 in front of the last amplifier module to produce a flat-top pulse spectrum. A flat-top spectrum is indeed transformed into a flat-top pulse after sufficient pulse stretching, because there is a direct relation between spectral content and time delay after sufficient pulse stretching. It can be shown that even values of self-phase modulation as large as 10*π can be tolerated for flat-top pulses without incurring significant pulse distortions.
[0197] An amplitude filter as shown in FIG. 15 may in turn also be used to control the amount of higher-order dispersion in the amplifier chain for strongly chirped pulses in the presence of self-phase modulation when reshaping of the pulse spectrum in the amplifier can be neglected, i.e., outside the regime where parabolic pulses are generated. In this case self-phase modulation produces an effective amount of higher-order dispersion of:
[0000]
β
n
SPM
=
γ
P
0
L
eff
n
S
(
ω
)
ω
n
ω
=
0
,
[0000] where P 0 is the peak power of the pulse and S(ω) is the normalized pulse spectrum. L eff is the effective nonlinear length L eff =[exp(gL)−1]/g, where L is the amplifier length and g is the amplifier gain per unit length. Thus by accurately controlling the spectrum of strongly chirped pulses with an amplitude filter as shown in FIG. 15 , any amount of higher-order dispersion can be introduced to compensate for the values of higher-order dispersion in a chirped pulse amplification system. It can indeed be shown for 500 fs pulses stretched to around 1 ns, a phase shift of ≈10 π is sufficient to compensate for the third-order dispersion of a bulk grating compressor (as shown in FIG. 5 ) consisting of bulk gratings with 1800 grooves/mm. Attractive well-controllable amplitude filters are for example fiber transmission gratings, though any amplitude filter may be used to control the pulse spectrum in front of such a higher-order dispersion inducing amplifier.
[0198] As another embodiment for the combination of an amplifier module with a pulse picker, the configuration displayed in FIG. 16 can be used. Since very high energy pulses require large core multi-mode fibers for their amplification, the control of the fundamental mode in a single-pass polarization maintaining fiber amplifier may be difficult to accomplish. In this case, it may be preferred to use a highly centro-symmetric non-polarization maintaining amplifier to minimize mode-coupling and to obtain a high-quality output beam. To obtain a deterministic environmentally stable polarization output from such an amplifier, a double-pass configuration as shown in FIG. 16 may be required. Here a single-mode fiber 55 is used as a spatial mode filter after the first pass through the amplifier 56 ; alternatively, an aperture could be used here. The spatial mode filter 55 cleans up the mode after the first pass through the multi-mode amplifier 56 , and also suppresses amplified spontaneous emission in higher-order modes that tends to limit the achievable gain in a multi-mode amplifier. Lenses 60 can be used for coupling into and out of amplifier 56 , spatial mode filter 55 , and pulse pickers 52 a and 52 b . The Faraday rotator 57 ensures that the backward propagating light is polarized orthogonal to the forward propagating light; the backward propagating light is coupled out of the system at the shown polarization beam splitter 58 . To optimize the efficiency of the system, a near-diffraction limited source is coupled into the fundamental mode of the multi-mode fiber 56 at the input of the system, where gain-guiding can also be used to further improve the spatial quality of the beam amplified in the multi-mode fiber. To count-down the repetition rate of the pulse train delivered from a SM and to suppress amplified spontaneous emission in the multi-mode amplifier, a 1st optical modulator 52 a can be inserted after the first pass through the multi-mode amplifier. An ideal location is just in front of the reflecting minor 59 as shown. As a result a double-pass gain as large as 60-70 dB could be obtained in such a configuration, minimizing the number of amplification stages required from amplifying seed pulses with pJ energies up to the mJ energy level. This type of amplifier is fully compatible with the SMs, PSMs and PCMs as discussed before, allowing for the generation of femtosecond pulses with energies in the mJ regime. As another alternative for the construction of a high-gain amplifier module, a count-down of the repetition rate from a pulse train delivered by a SM can also be performed with an additional 2nd modulator 52 b prior to injection into the present amplifier module as also shown in FIG. 16 . The repetition rate of transmission windows of the 1st modulator 52 a should then be either lower or equal to the repetition rate of the transmission window of the 2nd modulator 52 b . Such a configuration is not separately shown. FIG. 16 shares some similarities with FIG. 5 of U.S. Pat. No. 5,400,350, which is hereby incorporated by reference.
[0199] FIG. 17 represents an embodiment of the femtosecond fiber oscillator embodied in a fiber laser cavity 100 . A polarization-maintaining gain fiber 101 has a core 102 and cladding region 103 . The fiber core 102 is doped with rare-earth ions, such as Yb, Nd, Er, Er/Yb, Tm or Pr, to produce gain at a signal wavelength when the laser is pumped with diode laser 104 . The fiber core can be single-mode or multi-mode. The fiber laser cavity 100 further contains an integrated fiber polarizer 105 and a chirped fiber Bragg grating 106 . Both of these elements, 105 and 106 , are generally constructed of short fiber pigtails (e.g., 0.001-1 m in length), which are preferably fusion-spliced to fiber 101 using splices 107 , 108 and 109 . Alternatively, fiber polarizer 105 can be spliced in front of beam expander 110 . When using multi-mode fiber, splice 107 is selected to match the fundamental mode in the gain fiber 101 .
[0200] An exemplary integrated fiber polarizer in accordance with the invention comprises a polarization-maintaining undoped polarizer fiber (PF), with two orthogonal polarization axes, where the loss along one polarization axis is significantly higher than the loss along the other polarization axis. Alternatively, a very short section (less than 1 cm) of non-birefringent fiber (i.e., non-polarization-maintaining fiber) can be sandwiched between two sections of polarization-maintaining fiber, where the polarization axes of the polarization-maintaining fibers are aligned with respect to each other. By side-polishing the non-birefringent fiber, e.g., down to the evanescent field of the fiber core, along one of the axes of the birefringent fiber, and coating the polished region with metal, high extinction polarization action can be obtained along one of the axes of the birefringent fiber. The design of side-polished fiber polarizers is well known in the field and not discussed further here.
[0201] For optimum laser operation, the fiber polarization axes of the PF are aligned parallel to the polarization axes of the gain fiber 101 . To ensure stable modelocked operation, the polarizer preferably effectively eliminates satellite pulses generated by any misalignment between the polarization axes of the PF and the gain fiber 101 .
[0202] Neglecting any depolarization in the all-fiber polarizer itself, it can be shown by applying a Jones matrix calculation method that for a misalignment of the polarization axes of gain fiber 101 and fiber polarizer 105 by cc degrees, the linear reflectivity R from the right-hand side of the cavity varies approximately between R=1-0.5 sin 2 2α and R=1 depending on the linear phase in the gain fiber 101 . If the group delay along the two polarization axes of the gain fiber is larger than the intra-cavity pulse width, any satellite pulse is suppressed by sin 4 α after transmission through the polarizer. Typical fiber splicing machines can align polarization-maintaining fibers with an angular accuracy of less than ±2°; hence any reflectivity variation due to drifts in the linear phase between the two polarization eigenmodes of fiber 101 can be kept down to less than 3×10 −3 , whereas (for sufficiently long fibers) any satellite pulses obtained after transmission through the polarizer can be kept down to less than 6×10 −6 when using an integrated polarizer.
[0203] The chirped fiber Bragg grating 106 is preferably spliced to the PF 105 at splice position 108 and written in non-polarization-maintaining fiber. In order to avoid depolarization in the fiber Bragg grating, the Bragg grating pig-tails are preferably kept very short, e.g., a length smaller than 2.5 cm is preferable between splice locations 108 and 109 . To obtain a linear polarization output, a polarization-maintaining fiber pig-tail is spliced to the left-side of the fiber Bragg grating at splice location 109 . The laser output is obtained at a first fiber (or cavity) end 111 , which is preferably angle-cleaved to avoid back-reflections into the cavity. An alternative preferred design is with the fiber grating written in polarization-maintaining fiber.
[0204] Fiber Bragg grating 106 serves two functions. First, it is used as an output mirror (i.e., it feeds part of the signal back to the cavity) and, second, it controls the amount of cavity dispersion. In the present implementation, the chirped fiber Bragg grating has a negative (soliton-supporting) dispersion at the emission wavelength in the wavelength region near 1060 nm and it counter-balances the positive material dispersion of the intra-cavity fiber. To produce the shortest possible pulses (with an optical bandwidth comparable to or larger than the bandwidth of the gain medium), the absolute value of the grating dispersion is selected to be within the range of 0.5-10 times the absolute value of the intra-cavity fiber dispersion. Moreover, the fiber Bragg grating is apodized in order to minimize any ripple in the reflection spectrum of the grating. Accordingly, the oscillation of chirped pulses is enabled in the cavity, minimizing the nonlinearity of the cavity and maximizing the pulse energy. Chirped pulses are characterized in having a pulse width which is longer than the pulse width that corresponds to the bandwidth limit of the corresponding pulse spectrum. For example the pulse width can be 50%, 100%, 200% or more than 1000% longer than the bandwidth limit.
[0205] Alternatively, the oscillation of chirped pulses is also enabled by using negative dispersion fiber in conjunction with positive dispersion chirped fiber Bragg gratings. Pulses with optical bandwidth comparable to the bandwidth of the gain medium can also be obtained with this alternative design.
[0206] A SAM 112 at a second distal fiber end 113 completes the cavity. In an exemplary implementation a thermally expanded core (TEC) 110 is implemented at cavity end 113 to optimize the modelocking performance and to allow close coupling of the SAM 112 to the second fiber end 113 with large longitudinal alignment tolerances. Etalon formation between the fiber end 113 and the SAM 112 is prevented by an anti-reflection coating deposited on fiber end 113 (not separately shown). In the vicinity of the second fiber end 113 , fiber 101 is further inserted into ferrule 114 and brought into close contact with SAM 112 . Fiber 101 is subsequently fixed to ferrule 114 using, for example, epoxy and the ferrule itself is also glued to the SAM 112 .
[0207] The pump laser 104 is coupled into the gain fiber 101 via a lens system comprising, for example, two lenses 115 and 116 and a V-groove 117 cut into fiber 101 . Such side-coupling arrangements are described in, for example, U.S. Pat. No. 5,854,865 ('865) to L. Goldberg et al. Alternatively, fiber couplers can be used for pump light coupling.
[0208] An exemplary design for a SAM in accordance with the present invention is shown in FIG. 18 a . For example, SAM 200 includes an InGaAsP layer 201 with a thickness of 50-2000 nm. Further, layer 201 is grown with a band edge in the 1 μm wavelength region; the exact wavelength is defined by the sought emission wavelength of the fiber laser and can vary between 1.0-1.6 μm. The InGaAsP layer 201 is further coated or processed with a reflective material such as Au or Ag. A dielectric mirror or semiconductor Bragg reflector 202 is located beneath layer 201 and the entire structure is attached to heat sink 203 , based on, for example, metal, diamond or sapphire.
[0209] In order to cover a broad spectral range (e.g., greater than 100 nm) metallic minors are preferred. When using a metallic minor it is advantageous to remove the substrate (InP) by means of etching. When using HCl as an etching solvent the etching selectivity between InGaAsP and InP can be low, depending on the compound composition of InGaAsP. An etch-stop layer is beneficial between the substrate and the InGaAsP layer. InGaAs can be a proper etch-stop layer. When adding an InGaAs layer with a band-gap wavelength shorter than 1.03 μm, lattice relaxations can be avoided by keeping the thickness below 10 nm.
[0210] The InGaAsP layer can further be anti-reflection coated with layer 204 on its upper surface to optimize the performance of the SAM. Because of the saturable absorption by InGaAsP, the reflectivity of the SAM increases as a function of light intensity, which in turn favors the growth of short pulses inside the laser cavity. The absence of Al in the saturable absorber layer prevents oxidization of the semiconductor surfaces in ambient air and thus maximizes the life-time and power handling capability of the structure.
[0211] Instead of InGaAsP, any other Al-free saturable semiconductor can also be used in the construction of the SAM. Alternatively, Al-containing semiconductors can be used in the SAM with appropriately passivated surface areas. Surface passivation can, for example, be accomplished by sulfidization of the semiconductor surface, encapsulating it with an appropriate dielectric or with an Al-free semiconductor cap layer. An AlGaInAs absorber layer grown lattice-matched on InP can be surface-passivated with a thin (about 10 nm range) cap layer of InP. AlGaInAs with a higher band gap energy than the absorber layer can also be used for a semiconductor Bragg reflector in combination with InP. Among concepts for semiconductor Bragg mirrors lattice-matched to InP, an AlGaInAs/InP combination has an advantage over an InGaAsP/InP Bragg reflector due to its high refractive index contrast.
[0212] Instead of a bulk semiconductor saturable absorber, a MQW saturable absorber structure as shown in FIG. 18 b may also be used. In this case, the SAM 205 conveniently comprises MQW structures 206 , 207 and 208 separated by passive spacer layers 209 - 212 in order to increase the saturation fluence and depth-selective ion-implantation concentration of each MQW section. Additional MQW structures can further be used, similarly separated by additional passive spacer layers. To reduce the wavelength and location sensitivity of the MQW saturable absorbers, the width of the spacer layers varies from spacer layer to spacer layer. Furthermore, multiple bulk layers with thicknesses larger than 500 Å can replace the MQW structure. The MQW layers, in turn, can contain several layers of quantum wells and barriers such as, for example, InGaAs and GaAs, respectively. Top surface 209 can further be anti-reflection coated (not shown); a reflective structure is obtained by including minor structure 213 . The entire structure can be mounted on heat sink 214 .
[0213] The control of the response time of the saturable absorption for concomitant existence of fast and slow time constants is realized by introducing carrier trap centers with depth controlled H+ (or other ions) implantation. The implantation energy and dose are adjusted such that part of the absorbing semiconductor film contains a minimal number of trap centers. For example the semiconductor layer with the minimal number of trap centers can be selected to be at the edge of the optical penetration range of exciting laser radiation. Such a design serves only as an example and alternatively any semiconductor area within the optical penetration range can be selected to contain a minimal number of trap centers. Hence distinctive bi-temporal carrier relaxation is obtained in the presence of optical excitation. As an illustration of depth selective ion implantation, FIG. 19 shows the measurement of the depth profile of H+ ion implantation of an InGaAsP absorber film taken from secondary ion mass spectroscopy (SIMS).
[0214] The obtained bi-temporal carrier life-time obtained with the semiconductor film with a proton concentration as shown in FIG. 19 , is further illustrated in FIG. 20 . Here the reflectivity modulation (dR/R 0 ) of a semiconductor saturable minor due to excitation of the saturable mirror with a high energy short pulse at time t=0 is shown as a function of time delay. The measurement was obtained with a pump-probe technique, as well known in the art. FIG. 20 clearly displays the bi-temporal response time due to fast (<1 ps) and slow (>>100 ps) recovery. The distinctive fast response originates from the depth region with high trap concentration, while the slow component results from the rear depth region with a much lower trap center concentration.
[0215] When employing this absorber in the laser system described with respect to FIG. 17 , Q-switched mode-locking is obtained at intracavity power levels of a few mW. At the operating pump power level, stable cw mode-locking evolving from Q-switch mode-locking is observed. In contrast, no Q-switching and no mode-locking operation is obtained with the same semiconductor material implanted uniformly with protons without bi-temporal carrier relaxation (exhibiting only fast carrier relaxation).
[0216] We emphasize that the description for FIG. 19 and FIG. 20 is to serve as an example in controlling 1) the fast time constant, 2) the slow time constant, 3) the ratio of the fast and slow time constants, 4) the amplitude of the fast response, 5) the amplitude of the slow response, and finally 6) the combination of all of the above by ion implantation in a saturable absorber. Thus, the concept depicted hereby can be applicable for any type of laser modelocked with a saturable absorber. Specifically, in the presence of un-avoidable large spurious intra-cavity reflections such as in fiber lasers or thin disk lasers (F. Brunner et al., Sub-50 fs pulses with 24 W average power from a passively modelocked thin disk Yb:YAG laser with nonlinear fiber compression, Conf. on Advanced Solid State Photonics, ASSP, 2003, paper No.: TuAl), the disclosed engineerable bi-temporal saturable absorbers can greatly simplify and stabilize short pulse formation.
[0217] The preferred implantation parameters for H+ ions in GaAs or InP related materials including MQW absorbers are as follows: The doses and the implantation energies can be selected from 10 12 cm −2 to 10 17 cm −2 and from 5 keV to 200 keV, respectively, for an optically absorbing layer thickness between 50 nm and 2000 nm. For MQW absorbers, the selective ion-implantation depth is rather difficult to measure because the shallow MQW falls into the implantation peak in FIG. 19 . However, with the separation of MQW sections with spacers 209 - 212 (as shown in FIG. 18 ) it is feasible to employ depth selective ion implantation. For arsenic implantation, the implantation parameters for 50-2000 nm absorbing layer spans from 10 12 cm −2 to 10 17 cm −2 for the dosage and an implantation energy range of 100 keV to 1000 keV. In case of MQW saturable absorbers, the implantation range is preferably selected within the total thickness of the semiconductor layer structure containing MQW sections and spacers. In addition to H + and arsenic, any other ions such as for example Be can be implanted with controlled penetration depth by adjusting the above recipes according to the stability requirements of the desired laser.
[0218] FIG. 21 a illustrates an alternative implementation of the fiber end and SAM coupling in FIG. 17 . Here cavity 300 comprises an angle-polished thermal-diffusion expanded core (TEC) 301 . Fiber end 302 is brought into close contact with SAM 303 and fiber 304 is rotated inside ferrule 305 to maximize the back reflection from SAM 303 . Ferrule 305 is further angle-polished and SAM 303 is attached to the angle-polished surface of ferrule 305 . As shown in FIG. 21 a , fiber 304 is conveniently glued to the left-hand side of ferrule 305 . A wedge-shaped area between the fiber surface 302 and SAM 303 greatly reduces the finesse of the etalon between the two surfaces, which is required for optimum modelocked laser operation.
[0219] Instead of TEC cores, more conventional lenses or graded index lenses can be incorporated between the fiber end and the SAM to optimize the beam diameter on the SAM. Generally, two lenses are required. A first lens collimates the beam emerging from the fiber end, and a second lens focuses the beam onto the SAM. According to present technology, even conventional lenses allow the construction of a very compact package for the second fiber end. An implementation with two separate collimation and focusing lenses is not separately shown. To minimize unwanted back reflections into the fiber cavity and to minimize the number of components, a single lens can be directly fused to the fiber end as depicted in FIG. 21 b . As shown in FIG. 21 b , assembly 306 contains SAM 303 and fiber 304 as well as lens 307 , which focuses the optical beam onto the SAM. Lens 307 can also include a graded index lens.
[0220] To minimize aberrations in assembly 306 , an additional lens can also be incorporated between lens 307 and SAM 303 . Such an assembly is not separately shown. Alternatively, a lens can be directly polished onto fiber 304 ; however, such an arrangement has the disadvantage that it only allows a beam size on the SAM which is smaller than the beam size inside the optical fiber, thereby somewhat restricting the design parameters of the laser. To circumvent this problem, a lens surface can be directly polished onto the surface of a TEC; such an implementation is not separately shown. Another alternative is to exploit a graded-index lens design attached directly onto the fiber tip to vary the beam size on the SAM. In the presence of air-gaps inside the oscillator a bandpass filter 308 can be incorporated into the cavity, allowing for wavelength tuning by angular rotation as shown, for example, in FIG. 21 b.
[0221] Passive modelocking of laser cavity 100 ( FIG. 17 ) is obtained when the pump power exceeds a certain threshold power. In a specific, exemplary, implementation, polarization-maintaining fiber 101 was doped with Yb with a doping level of 2 weight %; the doped fiber had a length of 1.0 m; the core diameter was 8 um and the cladding diameter was 125 um. An additional 1.0 m length of undoped polarization-maintaining fiber was also present in the cavity. The overall (summed) dispersion of the two intra-cavity fibers was approximately +0.09 ps 2 . In contrast, the fiber grating 106 had a dispersion of −0.5 ps 2 , a spectral bandwidth of 10 nm and a reflectivity of 50%. The grating was manufactured with a phase mask with a chirp rate of 80 nm/cm.
[0222] When pumping with an optical power of 1.0 W at a wavelength of 910 nm, the laser produced short chirped optical pulses with a full width half maximum width of 1.5 ps at a repetition rate of 50 MHz. The average output power was as high as 10 mW. The pulse bandwidth was around 2 nm and hence the pulses were more than two times longer than the bandwidth-limit which corresponds to around 800 fs.
[0223] Alternatively, a fiber grating 106 with a dispersion of −0.1 ps 2 , closely matching the dispersion of the intra-cavity fiber, was implemented. The fiber grating had a reflectivity of 9% and a spectral bandwidth of 22 nm centered at 1050 nm. The grating was manufactured with a phase mask with a chirp rate of 320 nm/cm. The laser then produced chirped optical pulses with a full-width half maximum width of 1.0 ps at a repetition rate of 50 MHz with an average power of 25 mW. The pulse spectral bandwidth was around 20 nm and thus the pulses were around 10 times longer than the bandwidth limit, which corresponds to around 100 fs. The generation of pulses with a pulse width corresponding to the bandwidth limit was enabled by the insertion of a pulse compressing element; such elements are well known in the state of the art and are not further discussed here. The generation of even shorter pulses can be generated with fiber gratings with a bandwidth of 40 nm (and more) corresponding to (or exceeding) the spectral gain bandwidth of Yb fibers.
[0224] Shorter pulses or pulses with a larger bandwidth can be conveniently obtained by coupling the fiber output into another length of nonlinear fiber as shown in FIG. 22 . Here, assembly 400 contains the integrated fiber laser 401 with pig-tail 402 . Pig-tail 402 is spliced (or connected) to the nonlinear fiber 403 via fiber splice (or connector) 404 . Any type of nonlinear fiber can be implemented. Moreover, fiber 403 can also comprise a fiber amplifier to further increase the overall output power.
[0225] In addition to cladding pumped fiber lasers, core-pumped fiber lasers can be constructed in an integrated fashion. Such an assembly is shown in FIG. 23 . The construction of cavity 500 is very similar to the cavity shown in FIG. 17 . Cavity 500 contains polarization-maintaining fiber 501 and integrated fiber polarizer 502 . Fiber 501 is preferably single-clad, though double-clad fiber can also be implemented. The chirped fiber grating 503 again controls the dispersion inside the cavity and is also used as the output coupler. Fiber 501 , fiber polarizer 502 , fiber grating 503 and the polarization-maintaining output fiber are connected via splices 504 - 506 . The output from the cavity is extracted at angle-cleaved fiber end 507 . SAM 508 contains anti-reflection coated fiber end 509 , located at the output of the TEC 510 . Fiber 501 and SAM 508 are fixed to each other using ferrule 511 . The fiber laser is pumped with pump laser 512 , which is injected into the fiber via wavelength-division multiplexing coupler 513 .
[0226] In addition to chirped fiber gratings, unchirped fiber gratings can also be used as output couplers. Such cavity designs are particularly interesting for the construction of compact Er fiber lasers. Cavity designs as discussed with respect to FIGS. 17 and 23 can be implemented and are not separately shown. In the presence of fiber gratings as shown in FIGS. 17 and 23 , the fiber gratings can also be used as wavelength tuning elements. In this, the fiber gratings can be heated, compressed or stretched to change their resonance condition, leading to a change in center wavelength of the laser output. Techniques for heating, compressing and stretching the fiber gratings are well known. Accordingly, separate cavity implementations for wavelength tuning via a manipulation of the fiber grating resonance wavelength are not separately shown.
[0227] In the absence of a fiber grating, a mirror can be deposited or attached to one end of the fiber cavity. The corresponding cavity design 600 is shown in FIG. 24 . Here, it is assumed that the fiber 601 is core pumped. The cavity comprises an intra-cavity all-fiber polarizer 602 spliced to fiber 601 via splice 603 . Another splice 604 is used to couple WDM 605 to polarizer 602 . Polarization maintaining WDM 605 is connected to pump laser 606 , which is used to pump the fiber laser assembly. Saturable absorber minor assembly 607 , as described previously with respect to FIGS. 17 and 23 , terminates one cavity end and is also used as the passive modelocking element.
[0228] A second fiber polarizer 608 is spliced between WDM 605 and polarization-maintaining output coupler 609 to minimize the formation of satellite pulses, which can occur when splicing sections of polarization maintaining fiber together without perfect alignment of their respective polarization axes, as discussed in U.S. patent application Ser. No. 09/809,248. Typically, coupler 609 has a coupling ratio of 90/10 to 50/50, i.e., coupler 609 couples about 90-50% of the intra-cavity signal out to fiber pig-tail 610 . Pig-tail 610 can be spliced to a fiber isolator or additional fiber amplifiers to increase the pulse power. The second cavity end is terminated by mirror 611 . Minor 611 can be directly coated onto the fiber end face or, alternatively, minor 611 can be butt-coupled to the adjacent fiber end.
[0229] The increase in stability of cavity 600 compared to a cavity where the output coupler fiber, the WDM fiber and gain fiber 601 are directly concatenated without intra-fiber polarizing stages, can be calculated using a Jones matrix formalism even when coherent interaction between the polarization axes of each fiber section occurs.
[0230] Briefly, due to the environmental sensitivity of the phase delay between the polarization eigenmodes of each fiber section, for N directly concatenated polarization-maintaining fibers the reflectivity of a fiber Fabry-Perot cavity can vary between R=1 and R=1−(N×α) 2 , where α is the angular misalignment between each fiber section. Further, it is assumed that α is small (i.e., α<<10°) and identical between each pair of fiber sections. Also, any cavity losses are neglected. In fact, it is advantageous to analyze the possible leakage L into the unwanted polarization state at the output of the fiber cavity. L is simply given by L=1−R. For the case of N concatenated fiber sections, the maximum leakage is thus (N×α) 2 .
[0231] In contrast, a cavity containing N−1 polarizers in-between N sections of polarization-maintaining fiber is more stable, and the maximum leakage is L=2×(N−1)α 2 . Here, any depolarization in the fiber polarizers itself is neglected. For instance, in a case where N=3, as in cavity 600 , the leakage L into the wrong polarization axis is 2×(3−1)/3 3 =4/9 times smaller compared to a cavity with three directly concatenated fiber sections. This increase in stability is very important in manufacturing yield as well as in more reproducible modelocked operation in general.
[0232] In constructing a stable laser, it is also important to consider the construction of WDM 605 as well as output coupler 609 . Various vendors offer different implementations. An adequate optical representation of such general polarization-maintaining fiber elements is shown in FIG. 25 . It is sufficient to assume that a general coupler 700 comprises two polarization-maintaining fiber sections (pig-tails) 701 , 702 with a coupling point 703 in the middle, where the two polarization axes of the fiber are approximately aligned with respect to each other.
[0233] In order to ensure pulse stability inside a passively modelocked laser, the group-velocity walk-off along the two polarization axes of fiber sections 701 , 702 should then be longer than the full-width half maximum (FWHM) pulse width of the pulses generated in the cavity. For example, assuming a birefringent fiber operating at a wavelength of 1550 nm with a birefringence of 3×10 −4 corresponding to a polarization beat length of 5 mm at 1550 nm, the stable oscillation of soliton pulses with a FWHM width of 300 fs requires pig-tails with a length greater than 29 cm. For 500 fs pulses, the pig-tail length should be increased to around 50 cm.
[0234] Referring back to FIG. 24 , if a fiber pig-tailed output is not required, minor 611 as well as output coupler 609 can be omitted, and the 4% reflection from the fiber end adjacent to mirror 611 can be used as an effective output minor. Such an implementation is not separately shown.
[0235] Alternatively, a fiber-pig-tail can be butt-coupled to mirror 611 and also be used as an output fiber pigtail. Such an implementation is shown in FIG. 26 . Here, cavity 800 comprises core-pumped fiber 801 , fiber polarizer 802 and SAM assembly 803 . The laser is pumped via WDM 804 connected to pump laser 805 . An appropriate mirror (or minor coating) 806 is attached to one end of the cavity to reflect a part of the intra-cavity light back to the cavity and to also serve as an output minor element. Fiber pig-tail 807 is butt-coupled to the fiber laser output mirror 806 and an additional ferrule 808 can be used to stabilize the whole assembly. The polarization axes of fiber 807 and 801 can be aligned to provide a linearly polarized output polarization. Again, applying a Jones matrix analysis, cavity 800 is more stable than cavity 600 , because it comprises only one intra-fiber polarizing section. The maximum leakage in cavity 800 compared to a cavity comprising directly concatenated WDM and gain fiber sections is 50% smaller.
[0236] Similarly, a cladding pumped version of cavity 600 can be constructed. Cavity 900 shown in FIG. 27 displays such a cavity design. Fiber 901 is pumped via pump laser 902 , which is coupled to fiber 901 via lens assembly 903 and 904 as well as V-groove 905 . Alternatively, polarization-maintaining multi-mode fiber couplers or star-couplers could be used for pump power coupling. Such implementations are not separately shown. One end of the laser cavity is terminated with SAM assembly 906 (as discussed in regard to FIGS. 17 , 23 and 24 , which is also used as the modelocking element. A single-polarization inside the laser is selected via all-fiber polarizer 907 , which is spliced into the cavity via splices 908 and 909 . Polarization-maintaining output coupler 910 is used for output coupling. The laser output is extracted via fiber end 911 , which can further be spliced to additional amplifiers. Cavity minor 912 terminates the second cavity end. Output coupler 910 can further be omitted and the laser output can be obtained via a butt-coupled fiber pig-tail as explained with reference to FIG. 30 .
[0237] The cavity designs discussed with respect to FIGS. 17 , 23 , 24 , 26 and 27 follow general design principles as explained with reference to FIGS. 28 a - 28 c.
[0238] FIG. 28 a shows a representative modelocked Fabry-Perot fiber laser cavity 1000 , producing a linear polarization state oscillating inside the cavity containing one (or more) sections of non-polarization maintaining fiber 1001 and one (or more) sections of polarization maintaining fiber 1002 , where the length of fiber section 1001 is sufficiently short so as not to degrade the linear polarization state inside the fiber laser cavity, more generally a predominantly linear polarization state is oscillating everywhere within the intracavity fiber. The fiber laser output can be obtained from cavity end minors 1003 or 1004 on either side of the cavity. To suppress the oscillation of one over the other linear polarization state inside the cavity, either fiber 1001 or 1002 has a polarization dependent loss at the emission wavelength.
[0239] FIG. 28 b shows a representative modelocked Fabry-Perot fiber laser cavity 1005 , producing a linear polarization state oscillating inside the cavity containing two (or more) sections of polarization maintaining fibers 1006 , 1007 , where the length of fiber sections 1006 , 1007 is sufficiently long so as to prevent coherent interaction of short optical pulses oscillating inside the cavity and propagating along the birefringent axes of fibers 1006 , 1007 . Specifically, for an oscillating pulse with a FWHM width of τ, the group delay of the oscillating pulses along the two polarization axes of each fiber should be larger than τ. For oscillating chirped pulses τ represents the bandwidth-limited pulse width that corresponds to the oscillating pulse spectrum. Cavity 1005 also contains end minors 1008 and 1009 and can further contain sufficiently short sections of non-polarization maintaining fiber as discussed with reference to FIG. 28 a.
[0240] FIG. 28 c shows a representative modelocked Fabry-Perot fiber laser cavity 1010 , producing a linear polarization state oscillating inside the cavity containing one (or more) sections of polarization maintaining fiber 1011 , 1012 and one (or more) sections of polarizing fiber (or all-fiber polarizer) 1013 , where the length of fiber sections 1011 , 1013 is not sufficient to prevent coherent interaction of short optical pulses oscillating inside the cavity and propagating along the birefringent axes of fibers 1011 , 1013 , where the polarizing fiber is sandwiched between the sections of short polarization maintaining fiber. Cavity 1010 further contains cavity end minor 1014 and 1015 and can further contain short sections of non-polarization maintaining fiber as discussed with reference to FIG. 28 a . Moreover, cavity 1010 (as well as 1000 and 1005 ) can contain bulk optic elements 1016 , 1017 (or any larger number) randomly positioned inside the cavity to provide additional pulse control such as wavelength tuning or dispersion compensation. Note that the fibers discussed here can be single-clad, double-clad; the fibers can comprise also holey fibers or multi-mode fibers according to the system requirement. For example polarization maintaining holey fibers can be used for dispersion compensation, whereas multi-mode fibers can be used for maximizing the output pulse energy. Cavity minors 1014 , 1015 , 1003 , 1004 and 1008 , 1009 can further comprise bulk minors, bulk gratings or fiber gratings, where the fiber gratings can be written in short sections of non-polarization maintaining fiber that is short enough so as not to perturb the linear polarization state oscillating inside the cavity.
[0241] FIG. 29 serves as an example of a passively modelocked linear polarization cavity containing holey fiber for dispersion compensation. Cavity 1100 contains fiber 1101 , side-pumping assembly 1102 (directing the pump light either into the cladding or the core of fiber 1101 as explained before), saturable absorber minor assembly 1103 , all fiber polarizer 1104 and fiber output coupler 1105 providing an output at fiber end 1106 . All the above components were already discussed. In addition, a length of polarization maintaining holey fiber 1006 is spliced to the cavity for dispersion compensation and the cavity is terminated on the left hand side by mirror 1107 .
[0242] FIG. 30 serves as another example of a passively modelocked linear polarization cavity containing a fiber grating for dispersion compensation as applied to the generation of ultra-stable spectral continua. System 1400 comprises a small modification of the cavity explained with respect to FIG. 23 . System 1400 contains a fiber laser 1401 generating pulses with a bandwidth comparable to the spectral bandwidth of the fiber gain medium 1402 . Fiber laser 1401 further comprises saturable absorber minor assembly 1403 , wide bandwidth fiber grating 1404 , polarization maintaining wavelength division multiplexing (WDM) coupler 1405 , which is used to direct pump laser 1406 into fiber gain medium 1402 . Pump laser 1406 is preferably single-mode to generate the least amount of noise.
[0243] To enable the oscillation of short pulses with a bandwidth comparable to the bandwidth of the gain medium 1402 , saturable absorber mirror 1403 contains a bi-temporal saturable absorber, constructed with a bi-temporal life-time comprising a 1 st short life-time of <5 ps and a 2 nd long life-time of >50 ps. More preferable is a first life-time of <1 ps, to allow pulse shaping of pulses as short as 100 fs and shorter. By selecting the penetration depth of the implanted ions into the saturable absorber, even tri-temporal saturable absorbers can be constructed.
[0244] The wide-bandwidth grating is preferably selected to approximately match the dispersion of the intra-cavity fibers. The wide-bandwidth grating can be made in short non-polarization maintaining fibers and it can be made also in polarization maintaining fibers. In order to suppress detrimental effects from cross coupling between the two polarization axes of the fiber grating, coupling to cladding modes in such large bandwidth fiber gratings should be suppressed. Gratings with suppressed coupling to cladding modes can be made in optical fibers with photosensitive core and cladding area, where the photosensitive cladding area is index-matched to the rest of the cladding. Such fiber designs are well known in the state of the art and can for example be manufactured with an appropriate selection of germania and fluorine doping in the core and cladding regions and such fiber designs are not further discussed here. Because of the large generated bandwidth, splicing of such polarization maintaining gratings to the rest of the cavity without coherent coupling between the linear polarization eigenmodes is no problem. Alternatively, the fiber gratings can be written directly into the photosensitive gain fiber, with an index and dopant profile that suppresses coupling to cladding modes in the fiber grating.
[0245] To sustain large spectral bandwidth, fiber grating 1404 has preferably a spectral bandwidth >20 nm. A splice 1407 (or an equivalent bulk optic lens assembly) is used to connect the output of fiber laser 1401 to nonlinear fiber 1408 to be used for additional spectral broadening of the output of the fiber laser. For example fiber 1408 can comprise a highly nonlinear dispersion-flattened holy fiber. In conjunction with such fiber, smooth broad-bandwidth spectral profiles with bandwidths exceeding 100 nm can be generated. These spectral outputs can be used directly in high precision optical coherence tomography.
[0246] The pulses at the output of fiber 1408 are generally chirped and a dispersion compensation module 1409 can be inserted after the output from fiber 1408 for additional pulse compression. The dispersion compensation module can be spliced directly to fiber end 1408 when optical fiber is used for dispersion compensation. Alternatively, the dispersion compensation module can comprise two (or one) bulk grating (or prism) pair(s). Such bulk optic elements for dispersion compensation are well known in the state of the art and are not further discussed here. Coupling into and out of a bulk dispersion compensating module is obtained via lenses 1410 and 1411 . The output can also be from the other end of the cavity. The pulses generated after pulse compression can be as short as 20-200 fs. As mentioned previously this pulse compression module is optional and the dispersion compensation needed for this oscillator can be compensated by the pulse stretcher before and pulse compressor after the regenerative amplifier.
[0247] A fiber amplifier 1412 can also be added if further pulse energy is necessary.
[0248] Note that the discussion with respect to FIG. 30 serves only as an example of the use of bi- or multi-temporal saturable absorbers in the generation of mass producible ultra-broad band, low noise spectral sources. Other modifications are obvious to anyone skilled in the art. These modifications can comprise for example the construction of an integrated all-fiber assembly substituting elements 1408 , 1409 - 1411 and 1412 .
[0249] Though the discussion of the laser system with respect to FIG. 30 was based on the use of polarization maintaining fiber, non polarization maintaining fiber can also be used to produce pulses with bandwidth comparable to the bandwidth of the gain medium. In this case, saturable absorbers with depth controlled ion implantation are also of great value. Essentially, any of the prior art modelocked fiber laser systems described above (that were using saturable absorbers) can be improved with engineered bi- and multi-temporal saturable absorbers. Specifically, any of the cavity designs described in U.S. Pat. Nos. 5,450,427 and 5,627,848 to Fermann et al. can be used for the generation of ultra broadband optical pulses in conjunction with bi- or multi-temporal saturable absorbers and wide-bandwidth fiber Bragg gratings.
[0250] An embodiment with the fewest bulk optic components in the optical path is shown in FIG. 31 . The source of ultrashort pulses is a fiber-based MOPA 100 . This source is described in detail in Ser. No. 10/814,502 which is incorporated herein. A polarization-maintaining gain fiber 101 has a core 102 and cladding region 103 . The fiber core 102 is doped with rare-earth ions, preferably Yb, to produce gain at a signal wavelength when the laser is pumped with diode laser 104 . The pump diode is coupled into the cladding region 103 of fiber 101 using for example two lenses 105 and 106 and V-groove 107 , though coupling systems comprising more than two lenses can be used. Alternatively a WDM and a single mode laser diode can be used for in core optical pumping. The fiber core can be single-mode or multi-mode. The multi-mode fiber is designed to propagate single mode as is described in U.S. application Ser. No. 09/785,944 (incorporated by reference herein). The multi-mode fiber can also be multi-mode photonic crystal fiber as is described in Ser. No. 10/844,943 (incorporated herein). The fiber laser cavity 100 further contains a fiber Bragg grating 108 , written in polarization maintaining fiber, an optional polarizer (fiber or bulk) 109 and a saturable absorber assembly 110 . A bulk polarizer such as a cube polarizer is preferred. Fiber grating 108 can be chirped or un-chirped, where the polarization cross talk between the two polarization axes of the polarization maintaining fiber containing the fiber gratings is preferably less than 15 dB. Fiber end face 111 completes the basic MOPA system. The fiber Bragg grating can be written directly into fiber 101 or it can be spliced into the MOPA system at splice positions 112 and 113 , where the polarization axes of all involved fibers are aligned with respect to each other. The MOPA comprises an oscillator assembly 114 and an amplifier assembly 115 . The oscillator assembly 114 is bounded on the left hand side by fiber grating 108 and on the right hand side by saturable absorber assembly 110 . The amplifier assembly 115 is bounded by fiber grating 108 and fiber end 111 on the two opposite distal ends. In the present example fiber 101 is used both in the amplifier section and in the amplifier section. In general, however, different fibers can be used in the oscillator and amplifier, though to avoid feedback from the amplifier into the oscillator, the refractive index of both oscillator and amplifier fiber should be closely matched. The chirp of the output pulses can be conveniently compensated with the delivery fiber 118 , where lenses 116 and 117 are used to couple the output from the MOPA into the delivery fiber. Other pulse modification elements can be placed between the lenses such as an isolator, tunable filter or fiber gratings. The delivery fiber can comprise standard silica step-index fiber, holey fiber or photonic crystal fiber. The use of photonic crystal for dispersion compensation and pulse delivery was previously disclosed in Ser. No. 10/608,233. The delivery fiber 118 can also be spliced directly to fiber end face 111 , enabling a further integration of the laser assembly. The delivery fiber can also be sufficiently long to stretch the pulse sufficiently for amplification in the regenerative amplifier. The need for a compressor depends on the exact design of the regenerative amplifier.
[0251] The embodiment in FIG. 31 may be the simplest design, however the pulse conditioning shown in FIG. 1 and described in Ser. No. 10/960,923 are often necessary to obtain the needed specifications from the ultrafast source. Ser. No. 10/814,319 (incorporated by reference herein) teaches how to utilize various modules for pulse conditioning for a fiber laser source. Ser. No. 10/813,163 (incorporated by reference herein) describes utilizing some of these methods in a fiber chirped pulse amplification system. These pulse conditioning methods can be utilized in a regenerative amplifier system. FIG. 32 illustrates one embodiment of a laser system 550 having a monitoring and feedback control capability. In one embodiment of the laser system, monitoring the performance such as output power at some point(s) of the system and providing feedback to the diode pump drivers for active control can achieve a stable operation. FIG. 10 illustrates one embodiment of a laser system 550 having such a monitoring and feedback feature. The exemplary laser system 550 comprises an oscillator 552 coupled to an attenuator 556 via an isolator 554 . The output from the attenuator 556 is fed into a bandpass filter 558 whose output is then directed to a stretcher 561 and then an amplifier 560 . The output from the amplifier 560 is fed into the regenerative amplifier 563 and then a compressor 564 via an isolator 562 . It should be noted that the use of the attenuator 556 and the bandpass filter 558 are exemplary, and that either of these components may be excluded and any other modular components, including those disclosed herein, may be used in the laser system having feedback.
[0252] As shown in FIG. 32 , the laser system 550 further comprises a first monitor component 570 that monitors a performance parameter of the system after the oscillator 552 . The monitor 570 may comprise a sensor and controller. The monitor 570 may issue adjustment commands to a first driver 572 that implements those adjustment commands at the oscillator 552 .
[0253] The exemplary laser system 550 is shown to further comprise a second monitor component 574 that monitors a performance parameter of the system after the amplifier 560 . The monitor 574 may similarly comprise a sensor and controller. The monitor 574 can then issue adjustment commands to a second driver 576 that implements those adjustment commands at the amplifier 560 .
[0254] The monitoring of the system performed by the exemplary monitors 570 and/or 574 may comprise for example an optical detector and electronics that monitors optical intensity or power or other relevant parameter such as, e.g., frequency and spectrum. In response to such measurement, the monitor and the driver may induce changes in the oscillator and/or the amplifier by for example adjusting the pump intensity and/or rate, or adjusting the operating temperature. Temperature control of the oscillator can stabilize the gain dynamics as well as frequency fluctuations. Temperature control of the amplifier can also be used to stabilize the gain dynamics.
[0255] Other configurations for providing feedback to control the operation of the laser system may also be employed. For example, more or less feedback loops may be included. The electronics associated with these feedback loops are further described in Ser. No. 10/813,173 (incorporated by reference herein). A particularly important electronic control is to control the gain of the fiber amplifier. At 1 KHz repetition rate and lower, the gain of the fiber amplifier could be reduced between pulses to conserve the lifetime of the laser diode. Also the gain needs to be reduced on the fiber amplifier if a signal is lost from the short pulse source to protect from optical damage to the fiber amplifier or subsequent optical elements. The loops may involve electronics that perform operations such as calculations to determine suitable adjustments to be introduced. Examples are the mode-lock start-up and search algorithms that are disclosed in Attorney Docket No. A8828 (incorporated by reference herein). The start-up algorithm is shown in FIG. 37 . The feedback may be obtained from other locations in the system and may be used to adjust other components as well. The embodiments described in connection with FIG. 32 should not be construed to limit the possibilities.
[0256] A good Polarization Extinction Ratio (PER) is an important factor in maintaining good temporal pulse quality in a fiber-based ultrafast source for a regenerative amplifier. Poor polarization extinction creates ripple on the spectrum and on the chirped pulse. In various preferred embodiments, the light in the laser is linearly polarized. The degree of the linear polarization may be expressed by the polarization extinction ratio (PER), which corresponds to a measure of the maximum intensity ratio between two orthogonal polarization component. In certain embodiments, the polarization state of the source light may be maintained by using polarization-maintaining single-mode fiber. For example, the pigtail of the individual modular device may be fabricated with a polarization-maintaining fiber pigtail. In such cases, the PER of each modular stage may be higher than about 23 dB. Ensuring a high polarization extinction ratio throughout a series of modules is challenging despite the use of single mode polarization maintaining fiber. Degradation of the PER can occur at the fiber ferrule, fiber holder, or fusion splice in the series of modules.
[0257] Levels of PER above 23 dB may be obtained in a system by utilizing linear-polarizing optical components in the modules. Use of linear-polarizing components in the modules within systems that contain polarization degrading elements such as a fiber ferrule, fiber holder, or fusion splice is advantageous. The linear polarizers counter the superposition of the phase shift from each polarization degrading element. A superposed phase shift of 10 degrees may reduce the PER to about 15 dB in which case intensity fluctuation through a linear polarizer might be more than about 4%. In contrast, by embedding linear polarizers throughout the series of modules, the PER of the aggregate system can be substantially controlled such that the intensity fluctuation is below about 1%, provided that the PER of the individual module and splice is above about 20 dB.
[0258] FIG. 33 a illustrates one embodiment of a module that can be utilized for polarization correction or as variable attenuation. It is a variable attenuator module 730 comprising a housing 732 that contains optical components for providing a controllable amount of optical attenuation. The housing 732 may be sealed and thermally insulated as well. A first optical fiber connector 734 comprising an optical fiber 736 having an angle polished or cleaved end face passes through one sidewall of the housing 732 into an inner region of the housing containing the plurality of optical components. These optical components include a first lens 738 for collecting and preferably collimating light output from the optical fiber 736 , a variable wave plate 740 and a polarization selective optical element 742 . A second optical fiber connector 744 comprising an optical fiber 745 having an angle polished or cleaved end face passes through another sidewall of the housing 732 into the inner region containing the optical components. The variable waveplate 740 comprises a rotatable waveplate mounted on a rotatable wheel 746 and the polarization selective optical element 742 comprises a polarization beamsplitter such as a MacNeille prism. A second lens 748 disposed between the polarization selective optical element 742 couples light between the polarization beamsplitter 742 and the second optical fiber 745 . An optical path is formed from the first optical fiber 736 through the waveplate 740 and prism 742 to the second optical fiber connector 744 .
[0259] The waveplate 740 can be rotated to vary the distribution of light into orthogonal polarizations. The polarization beamsplitter 742 can be used to direct a portion of the light out of the optical path between the first and second fiber connectors 734 , 744 , depending on the state of the waveplate 740 . Accordingly, a user, by rotating the waveplate 740 and altering the polarization of light can control the amount of light coupled between the first and second optical fiber connectors 734 , 744 and thereby adjust the level of attenuation.
[0260] Preferably, the optical elements such as the first and second lenses 738 , 748 , the rotatable waveplate 740 and the MacNeille polarizer 742 comprise micro-optics or are sufficiently small to provide for a compact module. The elements in the housing 732 may be laser welded or otherwise securely fastened to a base of the housing. The housing 732 may be sealed and thermally insulated as well. In various preferred embodiments, these modules conform to Telcordia standards and specifications.
[0261] A particularly preferred embodiment for a fiber solid-state regenerative amplifier system ( 2000 ) is shown in FIG. 33 b . The mode-locked Yb oscillator ( 2100 ) operates at near 50 MHz with a chirped pulse width after the fiber stretcher ( 2200 ) between 2-100 ps. The mode-locking means is a saturable absorber mirror ( 2001 ). The gain is provided by a Yb: doped fiber ( 2002 ). The other output coupler is a chirped fiber grating ( 2003 ) that also provides for dispersion compensation. The center wavelength is between 1030-1040 nm with a bandwidth between 5-20 nm. The pulse is compressible to 100-300 fs. It is pumped in core by a conventional laser diode ( 2005 ) through a polarization maintaining WDM ( 2004 ). Side pumping the cladding is also suitable. The pulse energy is nearly 1 nJ after amplification. The fiber amplifier ( 2300 ) is slightly nonlinear. The spectral broadening is negligible but is dependent on the input power to the fiber amplifier. The Yb: fiber ( 2011 ) is approximately 3 meters long. It is also polarization preserving fiber. The Yb: fiber amplifier gain shapes and frequency shifts slightly the output. It is pumped co propagating by a conventional single mode laser diode ( 2009 ) through a polarization maintaining WDM ( 2010 ). Counterpropagating pumping and cladding pumping are also suitable. The output from the fiber amplifier is through a bulk collimator ( 2012 ) and a bulk isolator ( 2013 ). More than one isolator may be necessary at this point. Alternatively, an AOM pulse selector can be added to the end of the amplifier for isolation. A Faraday rotator and polarizer can be used at this point to separate the input of the regenerative amplifier ( 2400 ) from the output to the bulk grating compressor ( 2500 ). In addition there is an isolator ( 2007 ) between the fiber stretcher and fiber amplifier that includes an optical tap. The tap ( 2007 ) provides an optical sync output ( 2008 ) that is converted to an electrical signal by means of a photodiode. This signal is used to synchronize the regenerative amplifier pulse selector to the mode-locked fiber laser.
[0262] In this next embodiment an alternative source of the ultrafast pulses is a laser-diode or microchip laser. This embodiment is shown in FIGS. 34 and 35 . In FIG. 34 , the microchip laser is a single longitudinal Nd:vanadate source that provides a smooth temporal profile. The pulse width is 250 picoseconds. One solution for the compression fiber 62 is a standard single mode fiber with a mode field diameter of 5.9 μm and a NA of 0.12. The length of this compression fiber would be about 2 meters to create sufficient spectrum for a compression ratio of around 50. The output energy from microchip lasers can be 10 microjoules. In this case, the light intensity at the entrance face of the fiber will be near the damage threshold. A coreless end cap (not shown) can be used on the fiber so the mode can expand before the surface of the fiber. Otherwise, an amplifier with a larger mode field diameter can be used, such as a multimode fiber that propagates a single mode or a holey fiber amplifier as was used in (Furusawa et al “Cladding pumped Ytterbium-doped fiber laser with holey inner and outer cladding”, Optics Express 9, pp. 714-720, ( 2001 )). If a fiber with an order of magnitude higher mode area (mode field diameter of 19.5 μm) is used, then the parameters in the fiber will be the same as in the case with 1 microjoule input. So the fiber length would again be 2 meters.
[0263] Since there is no interplay between dispersion and self-phase modulation in this design, the pulse width stays the same as the original pulse width. The nearly linear chirp is created by the shape of the pulse. Such a fiber is normally called a “compression fiber”. We propose to replace this “compression fiber” with an amplifier fiber. The output of the amplifier will be a chirped pulse that can be compressed in a compressor. This saves the need of a stretcher.
[0264] For pulse energies significantly greater than 1 microjoule, the single mode beam should be further amplified in a multimode fiber. This chirped pulse source is ideal for amplification of ultrashort pulses by chirped pulse amplification in a regenerative amplifier. The pulse is then compressed after amplification. In this case the microchip 71 was operated at 0.5 μJ, and produced 250 ps, pulses and operating at the repetition rate of the regenerative amplifier. The compression fiber 62 is now a multimode amplifier fiber that amplified a single mode with a mode-field diameter of 17 μm. The pulse was then amplified to 30 microjoules where Raman limited the amplification. This pulse is now a chirped 250 ps pulse. It is further amplified in a solid state regenerative amplifier and compressed in a bulk grating compressor to typically less than 1 ps. FIG. 35 illustrates the source generally described in FIG. 3 of US Published Application 20040240037A1, incorporated by reference herein, with modification made to the chirped fiber grating at the end of the source to further stretch the pulses prior to amplification in the regenerative amplifier.
[0265] FIG. 36 illustrates a chirped pulse amplification system that utilizes conventional fiber stretchers, fiber amplifiers, bulk regenerative amplifiers and bulk grating compressors. In order to obtain high quality pulses from such systems, the control of higher-order dispersion and self-phase modulation is critical. A chirped pulse amplification system allowing for independent control of second- and third order dispersion is shown in FIG. 36 . In an exemplary embodiment, a seed source 101 based on a passively modelocked Yb fiber laser was used. Such passively modelocked Yb fiber lasers were previously described in application Ser. No. 10/627,069 and are not further described here. The seed source 101 produces positively chirped optical pulses with a bandwidth of 16 nanometers at a repetition rate of 43 megahertz with an average power of 16 milliwatts. The peak emission wavelength of the oscillator was 1053 nanometers. The pulses from the seed source were compressible to a pulse width of less than 150 femtoseconds, demonstrating that the chirp from the seed source was approximately linear. The output from the seed laser passed through an isolator (not shown) and a tunable bandpass filter 119 with a 15 nanometer bandwidth.
[0266] After the bandpass filter 119 , an output power of 5 milliwatts was obtained and a fiber stretcher 120 was used to stretch the pulses to a width of approximately 100 picoseconds. The fiber stretcher employed for producing stretched pulses had a length of approximately 200 meters and was based on conventional polarization maintaining single-mode step-index fiber. In FIG. 36 , the tunable bandpass filter 119 is shown inserted before the fiber stretcher 120 ; alternatively, the tunable bandpass filter 119 can also be inserted after the fiber stretcher 120 (system implementation is not separately shown).
[0267] A subsequent Yb-based polarization maintaining pre-amplifier 121 amplifies the stretched pulses to an average power of 500 milliwatts. A pulse picker 122 , based on an acousto-optic modulator and pig-tailed with polarization maintaining fiber, reduces the repetition rate of the pulses to 200 kilohertz, resulting in an average power of 1 milliwatt. The pulses from the pulse picker 122 were subsequently injected into a large-mode polarization maintaining Yb fiber power amplifier 123 and amplified to an average power of 950 milliwatts. The Yb power amplifier had a length of 3 meters and the fundamental mode spot size in the Yb power amplifier was around 25 micrometers. All fibers were either spliced together with their polarization axes aligned or connected to each other (with their polarization axes aligned) with appropriate mode-matching optics (not shown). The power amplifier 123 was cladding pumped via a lens 124 with a pump source 125 , delivering a pump power of about 10 watts at a wavelength of 980 nanometers. A beam splitting mirror 126 was implemented to separate the pump light from the amplified signal light. The amplified and stretched pulses from the power amplifier 123 are further amplified in a bulk solid state regenerative amplifier 129 . The output pulses from the regenerative amplifier 129 were compressed in a conventional bulk optics compressor 127 based on a single diffraction grating with a groove density of 1200 lines/mm, operating near the Littrow angle. Such bulk optics compressors are well known in the state of the art and are not further explained here. After the bulk optics compressor 127 , the output 128 will contain pulses with a full-width half-maximum (FWHM) width of around 330 femtoseconds and pulse energies around 1 millijoule. Alternative designs should be feasible including a system without the power amplifier. However, in this case the power amplifier is operating as the nonlinear fiber amplifier that is able to correct for higher order dispersion mismatch between the fiber stretcher and the bulk compressor.
[0268] Because stretched pulses can accumulate significant levels of third-order dispersion in the presence of self-phase modulation, gain-narrowing, gain-pulling and gain depletion, we refer to such pulses as cubicons. More generally, we can define a cubicon as a pulse that produces controllable levels of at least linear and quadratic pulse chirp in the presence of at least substantial levels of self-phase modulation (corresponding to a nonlinear phase delay >1) that can be at least partially compensated by dispersive delay lines that produce significant levels of second and third-order dispersion as well as higher-order dispersion. (Please note that for the compensation of linear pulse chirp, a dispersive delay line with second order dispersion is required, whereas for the compensation of quadratic pulse chirp, a dispersive delay line with third order dispersion is required and so on for higher orders of pulse chirp.) For a dispersive delay line to produce a significant level of 2 nd and 3 rd as well as possibly higher-order dispersion, the stretched pulses are typically compressed by more than a factor of 30. In addition cubicons can also be formed in the presence of resonant amplifier dispersion, gain narrowing, gain pulling as well as gain depletion, where we refer to gain depletion as an appreciable reduction in gain due to a single pulse. If a high power mode-locked oscillator an undoped fiber can be utilized to create the self-phase modulation. Spectral filtering will most likely be necessary to obtain the appropriate pulse shape to the chirped pulse. The chirped pulse width will need to be further expanded before amplification in the regenerative amplifier.
[0269] The importance of the pulse picker 122 has been described in Ser. No. 10/960,923 in that it alleviates the specifications on the optical switch in the regenerative amplifier. A further advantage is that it can be utilized as a variable attenuator for controlling the buildup time in the regenerative amplifier. An AO switch can be used here, however EO switches and EA switches are available in modules that conform to Telcordia standards and specifications. As pointed out in Ser. Nos. 10/437,057 and 10/606,829, it often takes two switches since the standard on off discrimination is 30 db while for lowering the rep rate from 30 MHz to 1 KHz requires an on off discrimination of more than 50 db for the majority of the energy to be in the one pulse operating at the lower repetition rate. Another use of the pulse picker is as a variable attenuator to control the nonlinearities in the fiber for dispersion correction. In cubicon amplification the nonlinearities are critical for dispersion control and the variable attenuation feature of the pulse pickers is a means for controlling the nonlinear affects in the fibers. Other variable attenuators can be used such as described in Ser. No. 10/814,319. Other means of controlling the nonlinearities of the fiber amplifier are utilizing the control of the fiber amplifier output as described above. These include varying the gain or temperature of the fiber amplifier by measuring the spectrum and or the output intensity from the fiber amplifier. Controlling the spectrum and the intensity accurately for cubicon amplification can be implemented.
[0270] The embodiment of a short pulse source in the picosecond and nanosecond range amplified in a fiber amplifier and amplified in a bulk amplifier is disclosed in application Ser. No. 10/927,374 (incorporated by reference herein) This system in some cases will have better performance when the bulk amplifier is utilized as a regenerative amplifier. This embodiment is shown in FIG. 38 . Fiber amplifier system 501 is described in detail in Ser. No. 10/927,374. The output pulse of the fiber amplifier system 501 is mode-matched by beam conditioning optics 506 to the fundamental mode of the solid state regenerative amplifier 505 . The regenerative amplifier 505 utilizes a bulk crystal gain material which is preferably directly diode pumped. The embodiment displayed in FIG. 38 has the advantage that the gain bandwidth of the regenerative amplifier can be matched to the fiber amplifier system. For example 1 ns pulses with a spectral bandwidth of 0.6 nm and a pulse energy exceeding 100 μJ, centered at a wavelength of 1064 nm can be generated in a fiber amplifier chain in conjunction with a diode seed laser, for injection into a Nd:YVO 4 amplifier, which has a spectral bandwidth of approximately 0.9 nm. As another example a modelocked Yb-fiber oscillator with center wavelength of 1064 nm and a bandwidth of several nm can be amplified and spectrally narrowed and matched to the gain bandwidth of the Nd:YVO 4 solid state amplifier. Thus 100 ps pulses with an energy of around 100 μJ and higher can be generated in a fiber amplifier chain and efficiently amplified in the regenerative amplifier. Without exploitation of spectral narrowing, the pulse energies from fiber amplifier chains designed for the amplification of 100 ps pulses in bulk Nd:YVO 4 amplifiers has to be reduced to avoid spectral clipping in the bulk amplifiers. Spectral narrowing is indeed universally applicable to provide high energy seed pulses for narrow line-width solid state amplifiers. For the example of bulk Nd:YVO 4 amplifiers, spectral narrowing is preferably implemented for pulse widths in the range of 20 ps-1000 ps.
[0271] Bulk solid-state regenerative amplifiers are also useful to increase the energy of pulses generated with fiber based chirped pulse amplification systems. Chirped pulse amplification is generally employed to reduce nonlinearities in optical amplifiers. The implementation of chirped pulse amplification is most useful for the generation of pulses with a width <50 ps. Due to the limited amount of pulse stretching and compression that can be achieved with chirped pulse amplification schemes, stretched pulses with an initial pulse width exceeding 1-5 ns are generally not implemented. Hence optical damage limits the achievable pulse energies from state of the art fiber based chirped pulse amplification systems (assuming fiber power amplifiers with a core diameter of 30 μm) to around 1 mJ. Single stage bulk solid state amplifiers can increase the achievable pulse energies normally by a factor of 10 while a regenerative amplifier has a gain of 10 6 . Therefore a regenerative amplifier can be preferable and give flexibility at a cost of complexity. One advantage is significantly lower pulse energies can be utilized from the fiber amplifier. A generic scheme 500 for the amplification of the output of a fiber based chirped pulse amplification system in a bulk optical amplifier is shown in FIG. 39 . Here short fs-ps pulses with pulse energies of a few nJ are generated in fiber oscillator 501 . The pulses from the oscillator are stretched in pulse stretcher 502 to a width of 100 ps-5 ns. The pulse stretcher is preferably constructed from a chirped fiber grating pulse stretcher as discussed with respect to FIG. 1 and can also be constructed from bulk optical gratings as well known in the state of the art. A pulse picker 503 reduces the repetition rate of the oscillator to the 1 kHz-1 MHz range to increase the pulse energy of the amplified pulses. A fiber amplifier chain represented by a single fiber 504 is further used to increase the pulse energy to the μJ-mJ level. Appropriate mode matching optics 506 is then used to couple the output of amplifier chain 504 into the bulk solid state amplifier 505 . Here bulk solid state amplifiers based on rods, slabs as well as thin disk concepts can be implemented. Appropriate bulk amplifier material are based for example on Yb:YAG, Nd:YAG, Nd:YLF or Nd:YVO 4 , Nd:glass, Yb, glass, Nd:KGW and others. Appropriate bulk amplifier materials and designs are well known in the state of the art and not further discussed here. A collimation lens 507 directs the output of the bulk solid state amplifier to the input of the compressor assembly. To minimize the size of a chirped pulse amplification system employing narrow bandwidth Nd-based crystals such as Nd:YAG, Nd:YLF, Nd:YVO 4 or Nd:KGW the use of a grism based compressor is preferred. The optical beam is directed to via mirror 508 to the grism 509 and an additional folding prism 510 is used to minimize the size of the compressor. Mirror 511 completes the compressor assembly. Such compressor assemblies have previously been used to compensate for third-order dispersion in wide-bandwidth chirped pulse amplification systems (i.e. chirped pulse amplification systems with a bandwidth >5 nm); no prior art exists applying grism technology to narrow bandwidth chirped pulse amplification systems (i.e. chirped pulse amplification systems comprising amplifiers with a spectral bandwidth <5 nm).
[0272] In an exemplary embodiment, fiber oscillator 501 generates 5 ps pulses, which are stretched by a chirped fiber grating stretcher to a width of 1 ns. After amplification in the fiber amplifier chain a pulse energy of 50 μJ is obtained at a repetition rate of 10 kHz. Further amplification in a Nd:YVO 4 solid state booster amplifier generates a pulse energy of 2 mJ. After recompression in the bulk grating compressor 10 ps pulses with an energy of 1 mJ are obtained. To ensure a compact design for the bulk grating compressor, preferably grisms with a groove density of 2800 l/mm are implemented. The whole compressor can then fit into an area of about 0.6×0.2 m by folding the optical beam path only once.
[0273] As discussed above, a burst of multiple pulses with different wavelengths, different pulse widths and different temporal delays may be desired. Referring to FIG. 40 , an embodiment of the laser means 51 is illustrated, which increasing the increasing the possible energy and average power from ultrafast fiber lasers. A longer pulse envelope can be obtained by utilizing a series of chirped gratings that reflect at different wavelengths. After amplification, a similar series of gratings can be placed to recombine/compress the pulses. In FIG. 40 , pulses from a femtosecond pulse source are passed through an acousto-optic modulator, a polarized beam-splitter and a Faraday rotator, and are then supplied to a series of chirped fiber stretcher gratings that operate on different portions of the input pulse spectrum. The spacings between the stretcher gratings can be l 1 , l 2 , l 3 . . . . In order to reconstruct the pulses after amplification in the fiber amplifier and the regenerative amplifier the spacings between a series of complementary bulk glass Bragg grating compressors are set to nl 1 , nl 2 , nl 3 , . . . , where n is the refractive index of the fiber between the stretcher fiber gratings, assuming that the bulk Bragg compression gratings are separated by air. The reconstructed pulse is output via a second beam splitter. As previously mentioned, the reconstructed pulse is generally the result of incoherent addition of the separately amplified spectral components of the input pulse.
[0274] If the distances between the compression and stretcher gratings are not equalized as described above, then multiple pulses will appear at the output. If the distances are not equal between the different sections than the temporal delays will not be equal. This can be beneficial for applications such as micro-machining. By varying the stretching and compression ratios, pulses with different pulse widths can be generated. A single broadband compression grating can be used when generating multiple pulses.
[0275] The utilization of the regenerative amplifier is not as flexible as an all fiber amplifier system for modification of the pulse shape. For example, long pulse widths are limited to repetitive features equal to the round trip time of the regenerative amplifier, e.g., approximately 10 nanoseconds. For a regenerative amplifier, the pulse train created by the gratings needs to be less than the round trip time of the regenerative amplifier.
[0276] Another embodiment of a multiple pulse source is shown in FIG. 41 . This source is utilized in the laser system shown in FIG. 42 . The Ytterbium amplifier is normally needed for the pulse intensity to be sufficient for amplification in the regenerative amplifier. The pulse compressor is optional. The multiple pulse source is a laser diode and multiple electronic drivers. In this case there are three sources with a delay generator that allows different delays to each electronic driver. A long pulse is generated by a conventional pulse driver for a laser diode. The shorter pulses are derived from short pulse laser diode drivers such as are available from Avtech. These signals are added through electronic mixers. The output is shown in FIG. 43 a . This is an oscilloscope screen measured with a sufficiently fast photodiode. There are three peaks observable. The output for one of the short pulses is shown in FIG. 43 b . The pulse width is approximately 100 ps. FIG. 43 c illustrates a three peak pulse that is formed by changing the delay between the pulses so the electronic signals overlap. The short pulses can also be chirped and then recompressed to femtosecond pulses by the final compressor as described in Ser. No. 08/312,912 and U.S. Pat. No. 5,400,350 (incorporated by reference herein). By appropriately choosing the chirp rates and frequency ranges a single bulk grating can compress a plurality of pulses.
[0277] Another embodiment of this is to utilize laser diodes at different wavelengths or polarization states and then combine these optically either with wavelength fiber combiners such as the wavelength router utilized in multiple wavelength telecomm systems or by fiber splitters as shown in FIG. 44 . It is also possible to utilize conventional mode-locked sources to give multiple pulses. The methods for utilizing fiber gratings and etalons as disclosed in U.S. Pat. No. 5,627,848 (incorporated by reference herein) as a source of multiple calibration pulses can be utilized here. Another method is to use fiber splitters with different path lengths as shown in FIG. 45 . Four pulses are output for each pulse from the Ultrashort pulse source. The four pulses are sequentially, temporally delayed by:
1. c(2L N +L 1 +L 4 ) 2. c(2L N +L 1 +L 3 ) 3. c(2L N +L 2 +L 4 ) 4. c(2L N +L 2 +L 3 )
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The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 11/243,825, filed Oct. 5, 2005, now U.S. Pat No. 7,190,736, issued Mar. 13, 2007, which is a continuation of application Ser. No. 09/943,968, filed Aug. 30, 2001, which is now U.S. Pat. No. 6,956,908, issued Oct. 18, 2005.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the timing of clock and data signals in integrated circuits. More specifically, the invention relates to simultaneous transmission of digital data and clock signals to eliminate skewing of the data and clock signals with respect to each other.
2. State of the Art
Digital integrated circuits typically include multiple logic elements, with the timing of operation of each logic element controlled by a clock signal. It is common for an integrated circuit chip to have one central clock generator, with the signal from the clock generator being distributed around the integrated circuit via clock-line interconnects. An important consideration in the design of digital integrated circuits is the timing of the arrival of clock and data signals at various logic elements.
Variation in clock signal arrival time is referred to as clock skew. A variety of techniques have been used to provide clock connections that are symmetrical and all of the same length in order to minimize clock skew at the various logic elements, including, for example, the methods of Yip and Carrig. See, K. Yip, “Clock tree distribution: balance is essential for a deep-submicron ASIC design to flourish,” IEEE Potentials, vol. 16, no. 2, pp. 11-14, April-May, 1997; and K. M. Carrig et al., “Clock methodology for high-performance microprocessors,” Proc. Custom Integrated Circuits Conference, Santa Clara, Calif., pp. 119-122, May 5-8, 1997. A number of prior art approaches are illustrated in FIGS. 1A-1D .
FIG. 1A illustrates an H-tree clock-distribution, which is used primarily in custom layouts and has varying tree interconnect segment widths to balance skew throughout the chip.
FIG. 1B shows a clock grid clock-distribution structure. The clock grid is the simplest clock-distribution structure and has the advantage of being easy to design for low skew. However, it is area inefficient and power hungry because of the large amount of clock interconnect required. Nevertheless, some chip vendors are using this clock structure for microprocessors.
FIG. 1C depicts a balanced tree clock-distribution structure. The balanced tree is the clock-distribution structure most commonly used in high performance chips. See, J. L. Neves et al., “Automated synthesis of skew-based clock-distribution networks,” VLSI Design, vol. 7, no. 1, pp. 31-57, 1998. In order to carry current to the branching segments, the clock line is widest at the root of the tree and becomes progressively narrower at each branch. As a result, the clock line capacitance increases exponentially with distance from the leaf cell (clocked element) in the direction of the root of the tree (clock input). Moreover, additional chip area is required to accommodate the extra clock line width in the regions closer to the root of the tree.
As shown in FIG. 1D , buffers may be added at the branching points of the balanced tree structure. Adding buffers at the branching points of the tree significantly lowers clock interconnect capacitance, because it reduces the clock line width required toward the root.
One prior art alternative to generating clock signals centrally and distributing them about the chip is to partition the chip design into blocks, as shown in FIG. 2 . A synchronous clock signal is used only within a single block, while communication between different blocks is performed on an asynchronous basis. See, T. Meincke et al., “Globally asynchronous locally synchronous architecture for large high-performance ASICs,” IEEE Symposium On Circuits and Systems, Orlando, Fla., Vol. 2, pp. 512-515, 30 May-2 Jun., 1999.
In the past, clock design has not typically been considered within the context of full chip timing. Existing design methodologies typically treat clock skew as a problem to be eliminated, and most designers strive to achieve zero skew. However, producing clock signals with zero skew may not be the optimum way to achieve either the safest or the highest performance clock design. It is often the case that, even after zero skew is attained, chip failures are caused by simultaneous switching current or other timing related problems.
There remains a need for a method of coordinating the timing of clock and data signals on a chip that can be achieved with a simple design and a minimum number of critical paths on the chip. It would be desirable to reduce the power consumption associated with clock-distribution lines or other chip timing circuitry. It would also be desirable to reduce the sensitivity of chip timing to process variations and various intermittent noises. Finally, there is an ongoing need for the development of higher speed methods for clocking data to provide enhanced chip performance.
BRIEF SUMMARY OF THE INVENTION
The methodology of the present invention addresses the problem of meeting a chip's timing requirements by combining clock timing with data path timing. Clock skew is treated not as a problem but as a controllable design variable which may be used to optimize overall chip timing. The invention achieves simultaneous distribution of clock and data signals by performing phase shift keying of digital data signals on clock frequency AC carrier signals, transmitting the keyed signals to different locations on the chip, and demodulating the keyed signals to retrieve digital data and clock signals. The inventive method may be used for signal interconnections on integrated circuits, interposers, and circuit boards.
The present invention reduces the number of critical paths on the chip in order to simplify designs and achieve timing closure. The present invention also allows increased clock frequency, thereby improving chip performance. Further, the present invention increases tolerance of chip timing to process variations and intermittent noise. The present invention may be used to create a larger timing budget to reduce power consumption. The present invention may also be used to reduce peak current and simultaneous switching noise to eliminate interference between digital and analog circuits.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In the drawings, which illustrate what is currently considered to be the best mode for carrying out the invention:
FIG. 1A shows a prior art H-tree clock-distribution structure;
FIG. 1B shows a prior art clock grid clock-distribution structure;
FIG. 1C shows a prior art balanced tree clock-distribution structure;
FIG. 1D shows a prior art balanced tree clock-distribution structure that includes buffers at branching points for reduction of clock-interconnect capacitance;
FIG. 2 illustrates a prior art method of partitioning a system into multiple blocks;
FIG. 3 is a block diagram of a device including circuitry for phase shift keying and demodulation of clock and digital data signals according to the present invention;
FIG. 4 is a block diagram depicting components of the inventive system used to perform differential Phase Shift Keying of digital data and clock signals;
FIG. 5 depicts a lead phase shift network used in the block diagram of FIG. 4 ;
FIG. 6 depicts a lag phase shift network used in the block diagram of FIG. 4 ;
FIG. 7A illustrates the signal V x =A sin(ωt+φ) output by the lead phase shift network of FIG. 5 ;
FIG. 7B shows the signal V x =A sin(ωt−φ) output by the lag phase shift network of FIG. 6 ;
FIG. 8 shows a demodulator circuit for recovering digital data from differential Phase Shift Keyed signals; and
FIG. 9 shows circuitry for recovering a clock signal from differential Phase Shift Keyed signals.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, analog signal techniques are used for signal interconnections on integrated circuits, interposers, and circuit boards. The clock signal is used as a high frequency carrier for signal interconnection and is modulated by the digital data using phase shift keying (PSK). PSK refers to a modulation technique that alters the phase of the carrier. Binary phase shift keying (BPSK), which is used in the present invention, has two phases, represented by the binary values 0 and 1. PSK is a special type of amplitude modulation, or a type of amplitude shift keying (ASK) which creates signals having values −1 or 1, and its bandwidth is the same as that of ASK. The inventive method includes the use of binary phase shift keying and low frequency differential modulation of the phase of a high frequency carrier. This approach results in a narrow bandwidth of the modulated signal comparable to that obtained with simple amplitude shift keying.
FIG. 3 is a block diagram of a device 2 including circuitry for performing phase shift keying of clock and digital data signals and subsequent demodulation of the PSK signals to retrieve the clock and digital data signals. Device 2 may be an integrated circuit, interposer, circuit board, or similar device. Device 2 includes phase shift keying circuitry 4 , which performs phase shift keying of the digital data signal X onto the clock signal CLK to generated phase shift keyed signals V x and V x . Phase shift keying circuitry 4 is located near the clock source on device 2 . PSK signals V x and V x are transmitted on interconnection lines 9 and 13 to digital signal demodulator 6 . Digital signal demodulator 6 demodulates PSK signals V x and V x to retrieve digital data signal X. Digital data signal X and PSK signals V x and V x are input to clock signal demodulator 8 , which demodulates PSK signals V x and V x to retrieve the clock signal. The clock signal and digital data signal X are input to clocked element 10 with no relative time delay between the two. Digital signal demodulator 6 and clock signal demodulator 8 are located close to clocked element 10 but may be located at some distance from phase shift keying circuitry 4 .
FIG. 4 is a schematic diagram of differential phase shift keying circuitry 4 that may be used to perform the differential phase shift keying signal interconnection technique of the present invention. A sinusoidal oscillator signal sin(ωt) having a radian frequency ω at the clock signal frequency for the chip is generated by oscillator 1 . The oscillator signal is sent simultaneously to phase shifter 3 and phase shifter 5 . Digital signal X is input to phase shifter 3 and controls the phase shift produced in the oscillator signal by phase shifter 3 , while the complementary digital signal X is input to phase shifter 5 and controls the phase shift produced in the oscillator signal by phase shifter 5 . The output of phase shifter 3 is fed to driver amplifier 7 and, from there, transmitted on interconnection line 9 . The output of phase shifter 5 is fed to driver amplifier 11 and subsequently transmitted on interconnection line 13 . Interconnection line 9 and interconnection line 13 are low impedance interconnection lines with matched terminating impedances 15 and 17 , respectively.
As shown in FIG. 5 , phase shifter 3 is a lead phase shift network made up of capacitor 19 and voltage variable resistor 21 forming a high pass filter. Capacitor 19 has a capacitance C 1 and voltage variable resistor 21 has a resistance of R 1 . Voltage variable resistor 21 is an NMOS transistor configured as a voltage variable resistor, with digital signal X connected to its gate to regulate the value of resistance R 1 . Phase shifter 3 produces a positive phase shift φ in the input signal when X has a logical high value. Thus, when the input to phase shifter 3 is sin(ωt) and X has a logical high value, the output will be V x =A sin(ωt+φ), and when X has a logical low value, the output will be V x =A sin(ωt), where A is an arbitrary constant. V x is plotted in FIG. 7A .
FIG. 6 depicts phase shifter 5 , which is a lag phase shift network made up of voltage variable resistor 23 and capacitor 25 forming a low pass filter. Capacitor 25 has a capacitance C 2 and voltage variable resistor 23 has a resistance of R 2 . Voltage variable resistor 23 is an NMOS transistor configured as a voltage variable resistor, with complementary digital input X connected to its gate to regulate the value of resistance R 2 . Phase shifter 5 produces a phase shift of equal magnitude but opposite sign to that produced by phase shifter 3 ; thus, it produces a negative phase shift φ in the input signal. Thus, when the input to phase shifter 5 is sin(ωt) and X has a logical high value, the output will be V x =A sin(ωt−φ), and when X has a logical low value, the output will be V x =A sin(ωt) where A is the arbitrary constant found in the expression for V x . V x is plotted in FIG. 7B .
Both phase shifter 3 and phase shifter 5 utilize phase shift networks of the type used in high frequency ring oscillators as disclosed in U.S. patent application Ser. No. 09/860,131, filed May 17, 2001, now U.S. Pat. No. 6,535,071, issued Mar. 18, 2003, in which the frequency of oscillation can be near f T of the transistors.
The phase shift keyed signals V x and V x are transmitted on matched interconnection lines 9 and 13 to the vicinity of the clocked element 10 . V x and V x each contain both clock and phase shift keyed digital data. Any signal skew which occurs over the length of interconnection lines 9 and 13 should be substantially the same for the signals on the two interconnection lines. At the clocked element 10 , PSK signals V x and V x are demodulated to recover the digital signal X and the clock signal.
Digital signal demodulator 6 , which is used to demodulate the digital signal encoded in signals V x and V x , is depicted in FIG. 8 . Digital signal demodulator 6 includes differential amplifier 27 , transistor amplifier circuit 29 which functions as an inverter or single stage amplifier, RC filter 31 , and comparator 33 . Signals V x and V x are fed into the positive and negative inputs, respectively, of a differential amplifier 27 . The difference between V x and V x is V x −V x =A sin(ωt+φ)−A sin(ωt−φ)=2A cos(ωt)sin(φ) when X has a logical high value. When X has a logical low value, V x −V x =0. As noted previously, A is an arbitrary constant amplitude, ω is the radian frequency of the carrier or oscillator frequency and φ is the amount of phase modulation at the input. Since φ, the amount of phase modulation, only has two values, zero and some finite value, then the differential output of the receiver is a pulse modulated sine or cosine wave at the carrier frequency.
Transistor amplifier circuit 29 is made up of diode-connected PMOS load transistor 35 and NMOS transistor 37 . The demodulator circuit of FIG. 8 takes advantage of the nonlinear characteristics of PMOS load transistor 35 to recover digital data from PSK signals. For simplicity, it can be assumed that PMOS load transistor 35 and NMOS transistor 37 have matching characteristics. Power supply voltage V DD is connected to the source of PMOS load transistor 35 . Power supply voltage V DD =4V T , where V T is the threshold voltage of the PMOS load transistor 35 and NMOS transistor 37 . The nominal DC voltage at the output of differential amplifier 27 and the input of transistor amplifier circuit 29 is 2V T when no AC signal is output by differential amplifier 27 . The corresponding voltage at the output of transistor amplifier circuit 29 is also 2V T. When V x and V x are applied to the inputs of differential amplifier 27 , the output is:
V 1 =2 V T +2 A cos(ω t )sin(φ) when X has a logical high value and V 1 =2 V T when X has a logical low value.
If the signal amplitude 2 A is made comparable to V T of the transistors, the output from transistor amplifier circuit 29 is:
V 2 =2 V T −2 A cos(ω t )sin(φ)−[4 A 2 /(4 V T )] cos 2 (ω t )sin 2 (φ),
which, as can be seen, includes a component that depends on the square of the AC component of the input signal.
RC filter 31 , which is a simple RC low pass filter at the output of transistor amplifier circuit 29 , is made up of resistor 39 having a resistance R 3 and capacitor 41 having a capacitance C 3 . The output of RC filter 31 is:
V 3 =2 V T −½[(4 A 2 /(4 V T ))sin 2 (φ)],
which is the DC component of the output of transistor amplifier circuit 29 and corresponds to the average value of cosine squared. Signal V 3 is input to comparator 33 and compared to reference signal V ref =2V T to produce an output signal V 4 which has a value of either sin 2 (φ) or zero. V 4 is the recovered digital data signal.
FIG. 9 illustrates the circuitry of clock signal demodulator 8 , which is used to recover the clock signal from the modulated RF carrier. Also shown are matched output impedances 15 and 17 of interconnection lines 9 and 13 , respectively.
Clock signal demodulator 8 includes two phase shift networks, lag phase shift network 43 and lead phase shift network 45 . Lag phase shift network 43 includes a low pass filter made up of voltage variable resistor 47 having resistance R 4 and capacitor 49 having resistance C 4 . The input to lag phase shift network 43 is signal V x from interconnection line 9 . Voltage variable resistor 47 is an NMOS transistor configured as a voltage variable resistor. The resistance R 4 of voltage variable resistor 47 is controlled by voltage V 5 , which is connected to the gate of the NMOS transistor. V 5 =V DC −BV 4 , where V DC is a constant DC voltage, B is an arbitrary constant, and V 4 is the recovered digital signal output by the demodulator circuit shown in FIG. 8 . The output of lag phase shift network 43 is fed into driver amplifier 51 . The output of driver amplifier 51 is V 7 =Dsin(ωt+φ−θ), where D is an arbitrary constant, ω is the radian frequency of the clock signal, φ is the phase shift introduced by phase shifter 3 (see FIG. 4 ) during phase shift keying of the digital data, and θ is the phase shift introduced by lag phase shift network 43 .
Lead phase shift network 45 includes a high pass filter made up of capacitor 53 having capacitance C 5 and voltage variable resistor 55 having resistance R 5 . The input to lead phase shift network 45 is signal V x from interconnection line 13 . Voltage variable resistor 55 is an NMOS transistor configured as a voltage variable resistor. The resistance R 5 of voltage variable resistor 55 is controlled by voltage V 6 , which is connected to the gate of the NMOS transistor. V 6 =V DC +BV 4 , where V DC , B, and V 4 are as defined previously. The output of lead phase shift network 45 is fed into driver amplifier 57 . The output of driver amplifier 57 is V 8 =Dsin(ωt−φ+θ), where D is the same arbitrary constant as found in the equation for V 7 , ω is the radian frequency of the clock signal, φ is the phase shift introduced by phase shifter 5 (see FIG. 4 ) during phase shift keying of the digital data, and θ is the phase shift introduced by lead phase shift network 45 .
In lag phase shift network 43 and lead phase shift network 45 , changing the resistance values R 4 and R 5 changes the phase shift of each network. In lead phase shift network 45 , decreasing R 5 increases the phase shift θ, making it more positive, since the corner frequency, ω c , moves up closer to the carrier frequency, ω. In lag phase shift network 43 , increasing R 4 lowers the corner frequency ω c and makes θ more negative, or shifts the phase of the incoming signal to more negative values.
The gains and characteristics of lag phase shift network 43 and lead phase shift network 45 are adjusted so that φ=θ. An analog adder 59 made up of resistors 61 , 63 , and 65 and amplifier 67 is used to average signals V 7 and V 8 to reduce noise and errors and yield output V 9 , which equals the clock signal sin(ωt) without the modulation of the digital data. In this manner, the clock signal can be recovered.
The frequency limiting element in this system is not the oscillator, carrier frequency, digital modulation frequency, or line characteristics but, rather, is likely to be the receiver amplifier. By using a relatively small number of CMOS elements in the circuitry of the invention, power consumption is kept low. The novel PSK method allows clock and data signals to be transmitted over any distance and to remain synchronized with each other. Speed and performance of the device are thus enhanced.
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A technique is described for simultaneously and synchronously transmitting digital data and a clock signal in a digital integrated circuit, circuit board, or system. The technique is based on the phase shift keying (PSK) modulation of an RF high frequency carrier which is distributed on low impedance interconnection transmission lines. The PSK modulation contains the digital data while the carrier itself constitutes the clock signal, and the clock signal and digital data are transmitted in a synchronous manner. The carrier frequency may be near f T , the maximum operation frequency of the transistors. Since the digital data and clock signal are simultaneously transmitted on the same interconnection, the digital data never becomes skewed with respect to the clock signal, or vice versa.
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CROSS-REFERENCE TO RELATED APPLICATION
The present invention claims the priority of provisional patent application No. 60/901,645, filed on Feb. 13, 2007, the contents of which are incorporated by reference. The present invention claims the benefit of design patent application No. 29/272,228 filed on Feb. 2, 2007 by the present inventor.
FIELD OF INVENTION
This present invention relates generally to an electrically-powered load-element, such as a pendant light assembly. More particularly, the present invention relates to a spring-mounted, tension-switch mechanism operable to electrically connect or disconnect an electrically-powered load element from a source of electrical power.
FEDERALLY SPONSORED RESEARCH
None.
SEQUENCE LISTING
None.
BACKGROUND OF THE INVENTION
Electricity is the motion of charged particles that create an electric charge. Early studies of electricity usually involved an electric charge that created some sort of light or arc. Ancient Greeks knew of electricity in the form of static when they rubbed objects against fur. When discharged, the static electricity would sometimes produce an arc. Perhaps the most documented historical event in this regard was when Benjamin Franklin, while studying lightening during a thunderstorm in his famous kite flying experiment, bridged the gap between lighting and static electricity. Studies such as these helped propel the theories in the minds of people such as Michael Faraday, Andre-Marie Ampere, George Sigmon Ohm, and Thomas Edison—inventor of the first commercially practical light bulb.
In order to power an electrical load element such as a light bulb, a circuit is needed to connect the electrical load element to a source of energy. A circuit consists of a number of electrical or electronic components connected by conductive materials. In order to power the electrical load element, the circuit needs a source of electrical energy such as alternating current energy, batteries, generators, etc. The circuit typically includes a switch, which controls the flow of the current, namely, it turns the electronic device on or off. The switch serves as a gateway to turning the electronic device on or off.
The earliest switch was simply the act of completing a circuit by connecting or disconnecting a wire. At its base form, a switch has two contacts that “close” to complete a circuit or “open” to disconnect the circuit. An example of an early switch is a lever switch, used by simply swinging a lever from the off position to the on position, or vice versa, to complete the circuit. These types of switches were used to power devices such as light bulbs to provide lighting in homes and businesses.
Electrical lighting provides more than just a utilitarian function. It is also used for aesthetic purposes. In the case of electronic devices such as a lighting fixture, attempts have been made and are being made to provide lighting devices that have not only a purposeful switch, but an aesthetically pleasing switch.
Today, conventional switches are of many varied configurations including the wall switch, the chain mounted rotary switch, dimmers, and the push button switch. However, each have their limitations in both utility and aesthetic qualities. Current methods for connecting or disconnecting an electrical load require one to engage the electronic fixture by touching the switch. For example, in order to turn the lights on in a room, one must engage a wall switch. To turn on a hanging light bulb in a basement, one must pull on a chain linked to a rotary switch. Known methods for connecting or disconnecting power to the light bulb do not allow one to engage the electrically-powered load element itself. The limitations of known methods will be discussed below.
The most common switch, the wall switch, is widely used in turning pendant or ceiling lights on and off in buildings. A wall switch is not located on the electrical device itself, but is place on the wall of a building in the general vicinity of the device. It is sometimes known as a “toggle” because it connects the circuit when toggled in one position, and disconnects when toggled in the opposite position.
A limitation with the use of a wall switch is that a single switch controls the supply of electricity to all lights in the circuit and as a result, all the lights must turn on or off together. It is difficult to turn on only one light bulb at a time on an as-needed or aesthetically pleasing basis. Using a wall switch, one would have to install a separate switch for each light bulb if that person only wanted to turn one light on at a time. Although it is currently a norm to have wall switches installed for lighting fixtures, many find it aesthetically unpleasant to have switches on walls as they hinder wall décor. Like many audio visual rooms found in schools and businesses, a separate switch for each light bulb could potentially lead to a wall full of switches which may detract from the aesthetics of a room. It is also difficult to find which wall switch engages which lighting element and as a result, one must engage each and every wall switch to find the correct light to engage.
A toggle switch attached to a light fixture may be used to remedy the problem of a wall full of switches, however, this device could not be a pendant or ceiling light, but must be a free-standing light fixture by its very nature. An attached toggle switch would allow one to turn lights on one at a time, however, the lighting fixture could not be a pendant or ceiling light simply because the attached toggle switch would be difficult to reach.
An embodiment of the current invention solves the problem of having to turn on all the pendant or ceiling lights in a room by allowing one to turn each hanging pendant light on or off independently without the use of unsightly wall switches or having to resort to free-standing light fixtures. This is made possible by the method of pulling on the pendant light fixture itself to turn the light on or off. One can possibly turn a single light on while leaving all other lights in the room off for purposes of ambience, for decreasing energy consumption, or for other utilitarian purposes in places such as a classroom.
Another version of an electric switch is simply the chain-mounted rotary switch found primarily in ceiling fans or on pendant light fixtures in a basement or closet. With these, one can turn a pendant or ceiling-attached electronic device on or off at its source, but not by pulling on the entire source itself. One must find the chain and pull on it to engage the switch. At times, finding the switch mechanism in a dark room can be a difficult challenge. The chain has been found to be unappealing and an annoyance. Currently, many ceiling fans are now using wall switches to control the fan, rather than these chain-mounted rotary switches because the chain has been found to be inconvenient. Pendant light fixtures with a chain mounted rotary switch have nearly been eliminated.
An embodiment of the present invention solves the problem of the annoyance of a chain on a chain-mounted rotary switch, but keeps the convenience of turning an electrically-powered load element on or off by pulling on the electrically-powered load element itself. It eliminates the chain and incorporates the switch mechanism with the device itself. It maintains the convenience of powering the device on or off by pulling on the device itself. One can simply pull on the electronic device, or an extension of the electronic device itself in order to turn the unit on or off. It would be easier finding the electronic device itself in a dark room, rather than a lone switch. Further, the pendant light would be aesthetically pleasing.
An embodiment of the present invention mechanically utilizes a push button switch in conjunction with a tension actuator bar and springs. Other versions of the present invention can use, but are not limited to, chain-mounted rotary switches, reed switches, wall mounted switches, dimmer switch, etc. The tension actuator bar is placed over the springs and push button switch and is balanced by stabilizing bars and bolts. The springs add resistance to the tension actuator bar in addition to the push button switch for smooth and reliable operation. Electrical wires are laced through the switch, tension actuator bar, and canopy to allow for the method of pulling the electrically-powered load element itself to turn the device on or off.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 illustrates a perspective view of an assembly of present invention.
FIG. 2 illustrates a perspective lateral cut-away view of an assembly of switch mechanism
FIG. 3 illustrates a flow chart of the method for electrically connecting or disconnecting electrically-powered load element.
DETAILED DESCRIPTION
FIG. 1 is a perspective view of an embodiment of a pendant light assembly. The assembly has a canopy encasing 12 and an electrically-powered load element 14 (which includes a heat resistant encasing 18 and the light bulb in the assembly) that is suspended by wires 20 . The assembly includes, but is not limited to, canopy encasing 12 . The purpose of canopy encasing 12 is to be aesthetically pleasing and non-essential but may also serve as a housing for electrical components in the assembly. Canopy encasing 12 is rectangular in the assembly, but may also be any shape such as a circle, triangle, rectangle, or any shape. Canopy encasing 12 may also include a canopy cover 16 . In the assembly, canopy cover 16 is a polycarbonate material. Wires 20 extend from canopy encasing 12 and connect to an electrically-powered load element 14 , as shown in the assembly. The assembly of the present invention may use wires 20 to suspend a heat resistant encasing 18 or electrically-powered load element 14 , but it is not limited to wires 20 to suspend electrically-powered load elements. The assembly may also include, but is not limited to, a heat resistant encasing 18 . Heat resistant encasing 18 allows electrically-powered load element 14 to stand upright to improve upon aesthetics. Heat resistant encasing 18 includes, but is not limited to, wire conduits that guide wires 20 to electrically-powered load element 14 and allowing it to hang upright. In the assembly, heat resistant encasing 18 includes, but is not limited to a rectangular shape. Other embodiments may include a variety of shapes such as circles, spheres, triangles, pyramids, etc. Electrically-powered load element 14 may be turned on or off by exerting pressure on electrically-powered load element 14 , heat resistant encasing 18 , wires 20 , or any other extension thereof. The pressure exerted includes, but is not limited to, downward force, lateral force, upward force, or any force thereof.
FIG. 2 is a perspective lateral cut-away view through canopy encasing 12 and canopy cover 16 constructed in accordance with an assembly of the present invention. A first wire 22 terminates and is electrically connected by first terminal of push button switch 44 and second terminal of push button switch 46 through a connection including, but not limited to, soldering. In this assembly a push button switch 24 is used, but other embodiments of switches such as rotary, reed, or other electromechanical switches may be used. An end of first wire 22 connects to a power source. The other end of first wire 22 is laced through an opening in tension bar actuator 26 and continues down through a first canopy wire exit 28 where the wire will ultimately connect to the terminals of an electrically-powered load element 10 (not shown in FIG. 2 ). Such a device may be, but is not limited to, a light bulb shown in FIG. 1 . An end of a second wire 30 connects to a power source. Second wire 30 is laced through an opening in tension bar actuator 26 and continues down through a second canopy wire exit 32 , where the wire will ultimately connect to said terminals of an electrically-powered load element 10 (not shown in FIG. 2 ). Spring(s) 34 underneath tension bar actuator 26 apply upward tension on tension bar actuator 26 . Tension bar actuator 26 extends above spring(s) 34 and over push button switch 24 in such a way that tension bar actuator 26 does not actuate push button switch 24 until a physical pressure is applied. Spring(s) 34 support tension bar actuator 26 to limit actuation until a physical pressure is applied. Stabilizing spacer(s) 36 may be placed on top of tension bar actuator 26 for purposes of allowing spring(s) 34 to apply the correct amount of tension on tension bar actuator 26 . A tension clip 38 may be placed on first wire 22 above and resting on tension bar actuator 26 . Another tension clip 38 may be placed on second wire 30 above and resting on tension bar actuator 26 . Tension clip 38 allows for equalized physical tension to be applied to tension bar actuator 26 and aids in the aesthetic alignment of an electrically-powered load element (not pictured in FIG. 2 ). Bolt(s) 40 may be placed through stabilizing spacer(s) 36 , tension bar actuator 26 , and spring(s) 34 in order to align the assembly of the invention correctly. In the present exemplary embodiment, canopy cover 16 includes an upstanding adapter 42 that in this implementation facilitates support of the invention in a track for track lighting.
FIG. 3 shows operation pursuant to an embodiment of the present invention, when a force is exerted on the heat resistant encasing 18 , pendant light fixture 14 , wires 20 , or any extension thereof, the device is turned on or off. The physical force exerts force on wire(s) 20 . Force translates to tension exerted on the tension bar actuator 26 by means of tension clip(s) 38 . Tension bar actuator 26 actuates power switch when correct amount of pressure is applied to push button switch 24 . Spring(s) 34 applies opposing force on tension bar actuator 26 allowing for completion of push button switch 24 once physical force is released.
Additional embodiments can include, but is not limited to, the use of only one spring 34 , or a different element offering opposing force. Other embodiments not include unnecessary elements such as canopy casing 12 , canopy cover 16 , heat resistant encasing 18 , stabilizing spacer 36 , bolt 40 , or upstanding adapter 42 . These elements add to aesthetics and efficient operation, but are not necessary for a working unit.
REFERENCE NUMERALS
10 . Terminals of an electrically-powered load element
12 . Canopy Encasing
14 . Electrically-powered load element
16 . Canopy Cover
18 . Heat resistant encasing
20 . Wires
22 . First Wire
24 . Push Button Switch
26 . Tension Bar Actuator
28 . First Canopy Wire Exit
30 . Second Wire
32 . Second Canopy Wire Exit
34 . Spring(s)
36 . Stabilizing Spacer
38 . Tension Clip
40 . Bolt(s)
42 . Upstanding Adapter
44 . First Terminal of Push Button Switch
46 . Second Terminal of Push Button Switch
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An apparatus designed to suspend an electrical device such as a light bulb and to turn the light bulb on or off by exerting a force on the bulb itself, an encasing around the bulb, the conductive leads, or an extension thereof. When force is exerted, tension causes a tension bar actuator to actuate an electrical switch, thus turning the bulb on or off.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device and a method for the dosed delivery of fluid.
2. Description of the Prior Art
The significance of the demand for a precise dosing of a fluid is increasing, for instance in gasoline direct injection in the context of designing a lean-mix engine. With a lean-mix engine design, a reduction of the CO 2 exhaust is intended.
For purposes of realizing a lean-mix engine, a high requirement is established for dosing of the fuel, namely a simultaneous axially symmetric fuel distribution, use of the engine given high temperature gradients of approximately 150°, a high injection pressure up to 250 bars, a short drive-dead-time of less than 0.1 ms, and a short switching time of less than 0.15 ms, among other things.
This requirement can be only insufficiently met using an electromagnetically driven dosing mechanism due to the limited switching time. A piezoelectric actuator, on the other hand, is characterized by a very short response time and dead time. However, given the use of a piezoelectric direct drive, the insufficient compensation of length modifications of the piezoactuator and housing which are conditioned by temperature effects or by aging and settling effects is disadvantageous. Also, a piezoactuator of great structural length is required for this, which is disadvantageous to production and is expensive.
In addition, a piezoelectric actuator combined with a membrane hydraulic results in problems such as, a mechanical calibration involving great outlay, a danger of breaking the membrane, and a low degree of effectiveness.
German Offenlegungsschrift 43 06 073 teaches a measuring device for fluids wherein a piezoelectric actuator via a fluid-filled chamber, drives a lifting element that controls a fluid delivery. This device has the disadvantage of a high outlay and a vulnerable design in the drive field, as well as a separation of the hydraulic circuits at the drive side and at the injection side.
German Offenlegungsschrift 195 19 191 discloses an injection valve wherein the movement of a piezoactuator directly controls a tappet by means of a piston-hydraulic stroke translation. This valve is reliant on the use of control surfaces at the valve tappet. Furthermore, a motion-commutating stroke translation is disclosed which presupposes a development for the hydraulic chamber that is expensive. The fluid is also delivered via at least one injection opening, whereby the danger of an occlusion exists, and whereby an axially symmetric fuel delivery is also strongly prevented.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a simplified, reliable and precise method and device for the dosed delivery of fluids.
The present invention provides a lifting element at the secondary side hydraulically connected to a primary drive by a hydraulic chamber. The primary drive hydraulically moves the lifting element, whereby the lifting element opens to the outside and directly controls a dosed fluid delivery.
To this end, the lifting element is driven into a borehole at the secondary side, which opens into the outside space at one side, such that the element can be displaced axially and is affected by leaks. The borehole at the secondary side is subjected to pressure of the fluid via a feed line. The borehole at the secondary side and the hydraulic chamber are fluidly connected to each other by the fit between the lifting element and a housing which is affected by leaks.
For purposes of dosing the fluid, a sealing element of the lifting element opens to the outside so that the lifting element opens, or respectively, closes off the pressurized borehole in relation to the outside environment at the secondary side.
Elements which are connected hydraulically from the primary drive up to and excluding the hydraulic chamber, such as a piezoactuator are located on the primary side. On the other hand, elements which are connected hydraulically downstream of the primary drive and the hydraulic chamber, such as the lifting element are located on the secondary side.
The present invention further provides that the primary drive is maximally withdrawn from the hydraulic chamber in the neutral position. In an embodiment, a discharged piezoactuator is used to move the primary drive. The pressure of the fluid in the hydraulic chamber corresponds to the pressure in the feed line, due to the leak-affected, that is hydraulically throttled in the connection between the feed line and the hydraulic chamber. The lifting element at the secondary side is shifted maximally toward the hydraulic chamber. In an embodiment, this shifting is conducted by a readjusting device at the secondary side. The lifting element employs a sealing element to close the borehole at the secondary side against the outside environment.
During the stroke process, the primary drive is shifted to the hydraulic chamber. This increases the pressure in the hydraulic chamber, so that the lifting element at the secondary side is pushed away from the hydraulic chamber more strongly. Because the fluid only reaches the hydraulic chamber in a throttled manner, the pressure buildup is not prevented by the fluid that is relatively weakly affected by leaks.
Beginning at a specific pressure in the hydraulic chamber, the forces exerted on the lifting element in the direction of the hydraulic chamber, such as the forces exerted by readjusting device, are overcome, and the lifting element moves away from the hydraulic chamber. By this motion, the sealing element attached to the lifting element moves away from the mouth of the borehole at the secondary side and to the outside. Fluid is delivered into the outside environment through the open mouth in a dosed manner.
For purposes of returning to the neutral position, the primary drive is again contracted. The pressure of the fluid in the hydraulic chamber drops to such an extent that the lifting element is again shifted in the direction of the hydraulic chamber. In an embodiment, the pressure drop results from the force exerted by the readjusting device at the secondary side. When the lifting element has been pushed back in the direction of the hydraulic chamber to such an extent that it closes the borehole at the secondary side against the outside again, fluid losses in the hydraulic chamber due to leakage flows are compensated by the fit between the lifting element and housing.
The present invention provides the following advantages with the use of the hydraulic chamber:
(1) A potentially excessively low stroke of the primary drive can be enhanced by a stroke translation onto the lifting element at the secondary side (e.g.: stroke of the piezoactuator 40 μm, stroke of the lifting element 240 μm, a corresponding stroke translation of 6:1). The advantages of the primary drive, such as a very rapid and linear response behavior, are thus combined with the advantage of a sufficient stroke. It is thus possible to avoid one disadvantage of a piezoelectric direct drive, namely the requirement of an excessive piezo length.
(2) Changes in length of the piezoactuator and of the housing together with what is built into it effected by changes, such as thermal effects, aging, or settling effects, are largely compensated in that the hydraulic chamber is pressurized with fluid via a leakage flow. Thus, the pressure in the hydraulic chamber is independent of its volume over the long term. This results in a high precision over a large temperature range. It is also possible to balance these effects using a hydraulic chamber with a stroke translation of 1:1 or with a stroke reduction.
(3) The relative orientation of the borehole at the secondary side has no influence on the control behavior. Because of this, there can be several different oriented subelements at the secondary side, such as lifting elements in their respective boreholes.
(4) In contrast to a mechanical translator system, the disadvantageous effect of bending of components, friction, or respectively, the wearing or tilting of mechanical components is avoided.
(5) The shifting of the primary drive is forwarded with immediacy and precision. The advantage of using a primary drive which can be controlled rather effectively and which has a short dead time, such as a piezoactuator or a magnetostatic actuator, is maintained.
(6) Compared to a dosing device with return of motion, there is the advantage of a simple layout in the region of the hydraulic chamber. This layout is insensitive to tolerance in production. In addition, due to the outwardly opening tappet, an axially symmetric fuel delivery at the mouth is achieved. Moreover, due to the filling of the hydraulic chamber so as to be affected by leaks, a complicated filling arrangement or a separate hydraulic circuit for the hydraulic chamber are forgone.
The present invention is not advantageously limited to fuel injection, such as gasoline injection, a diesel injection or a methane injection for a gas motor. Rather, other uses are imaginable, such as a control of a hydraulic valve. Such a hydraulic valve can be utilized for controlling a brake circuit or for dosing an active vibration damper.
In addition, the present invention is not limited by the type of fluid. The fluid can be a liquid, such as water, or a gas, such as compressed air. Given a utilization of the dosing device for fuel injection, the fluid is advantageously a liquid such as gasoline, diesel, kerosine, petroleum or alcohol, or a gas, such as methane or butane.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side sectional view of a device for dosed delivery of fluid constructed and operating in accordance with the principles of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A borehole 3 at a primary side and a parallel borehole 4 at a secondary side are installed in a housing 1, such that the two boreholes 3, 4 converge in a centered manner. They can also be perceived as one borehole with a varying diameter. This type of arrangement of two boreholes 3 and 4 opening into each other with a longitudinal axis along the same line carries the advantage of a simple and compact construction and correspondingly a simple production. The orientation of the two boreholes 3,4 relative to one another can also be realized differently, for instance offset or tilted relative to one another.
A pressure piston 11 is arranged in the borehole 3 at the primary side such that it can be displaced axially and at least partially lowered, as part of a primary drive, that is as part of a drive that can be controlled from the outside. A hydraulic chamber 2 is created by this arrangement inside the borehole 3 at the primary side. The hydraulic chamber 2 is pressurized with a fluid 6. It can also be constructed separately with a hydraulic connection to the boreholes 3,4.
The pressure piston 11 is pushed away from the hydraulic chamber by a readjusting device 13 at the primary side, as another part of the primary drive 5. The readjusting device 13 at the primary side can be a Bourdon spring (hollow cylinder with horizontal slots), for example, or it can advantageously include several cup springs arranged in parallel or in series. An actuator can also be used to automatically control the primary side readjusting device 13.
The fit between the pressure piston 11 and housing 1 is advantageously hydraulically tight. For purposes of a simpler design, it is advantageously sealed by means of a surrounding O-ring 18, which is inserted into a groove of the pressure piston 11. The O-ring 18 includes an elastomer material. A bead or membrane made of metal or plastic, for example, can also be used to seal the fit for purposes of enhancing the operational reliability and safety.
The pressure piston 11 is moved from its side which is averted from the hydraulic chamber 2 by an actuator 12 which is attached to the housing 1. As another subelement of the primary drive 5, the actuator 12 is advantageously a piezoelement. It can also be a multi-layer piezoactuator. The piezoactuator has the advantage that it responds to control signals very rapidly, and that its length adjustment is nearly exactly linear relative to the level of the control signal, such as a voltage or current signal. The use of a piezo multilayer system is advantageous in terms of control, due to the low operating voltage. The use of a ceramic-like piezo element with a high Curie temperature enables an operation over a broad temperature range. Besides a piezoactuator, a magnetostatic or electrostatic actuating element 12 can be used.
Between the actuator 12 and pressure piston 11, a spherical disk 19 is inserted, which comprises a corresponding support at the pressure piston 11 and which advantageously balances the tilts of the actuator 12, the housing 1 or the pressure piston 11 in order to prevent a gap resilience when an end face of the piezo is not plane parallel. The spherical disk 19 with the corresponding support can also be attached at the housing side between the actuator 12 and housing 1. However, the spherical disk 19 is not needed if there exists a sufficiently close fit between the actuator 12 and pressure piston 11.
The elements 5,11,12,13,19 at the primary side are assembled so as to be mechanically pressure-biased in a defined manner. This is advantageous given the use of a ceramic-like actuator 12, such as a ceramic piezoactuator, which can be easily destroyed by tensile stresses. The pressure bias can be additionally set by spacer disks (not illustrated) attached to the housing 1.
Of course, the primary drive 5 can also exists as an individual element, such as a piston-shaped piezoactuator. However, here the advantages of an optimized design of subelements with a conflicting requirement for material properties are forgone.
At a borehole 4 of the secondary side, a secondary side lifting element 7 is arranged such that it can be axially displaced and is affected by leaks to open into the hydraulic chamber 2. The primary drive 5 is thus connected hydraulically to the lifting element 7 by the hydraulic chamber 2. It is also possible for a number of boreholes 4 to open into the hydraulic chamber 2. The hydraulic chamber 2 can also be pressurized with fluid 6 directly by an additional fluid line (not illustrated). For purposes of venting the hydraulic chamber, a venting screw 25 is present.
The lifting element 7 includes a plurality of subelements 14-17. A jacking piston 14 in close proximity to the hydraulic chamber 2 is directed into the secondary side borehole 4 wherein it can be displaced axially and is affected by leaks. A piston rod 15 is connected to the jacking piston 14, which are depicted as one component here. A tappet 16 contacts the piston rod 15, whereby the piston rod 15 and the tappet 16 are not connected to each other fixedly. A mouth 10 of the borehole 4 at the secondary side can be closed against the outside by connecting the tappet 16 to a sealing element 17.
For purposes of realizing the piston-hydraulic stroke translation, the pressure-active surface of the pressure piston 11 is larger than that of the jacking piston 14. The "pressure-active surface" refers to the projection, in the direction indicated, of the surface that stands in contact with the fluid 6 of the hydraulic chamber 2. For example, the pressure-active surfaces of the pressure piston 11 and of the jacking piston 14, respectively correspond to its faces thereof that face the hydraulic chamber 2.
To obtain a predetermined maximum stroke, a catch 23 is advantageously provided for purposes of limiting the stroke of the jacking piston 14. The jacking piston 14 can be completely lowered into the borehole 4 at the secondary side or can even project partially into the hydraulic chamber 2. A part of the borehole 4 at the secondary side is constructed in the shape of a fluid chamber 9. The fluid chamber 9 is pressurized with the fluid 6 by a feed line 24.
A secondary side readjusting device 8 is attached in the fluid chamber 9. This device 8 includes a spiral spring 21, which is fastened at the tappet 16 by a Seeger ring 20, a snap ring, or some other similar fastening mechanism, and which presses the lifting element 7, or respectively, the tappet 16 in the direction of the hydraulic chamber 2. For purposes of filling with fluid 6 and of leakage compensation, the fluid chamber 9 can be connected to the hydraulic chamber 2 by a throttled connecting line or by a connecting line which is provided with a non-return valve (not illustrated) that opens in the direction of the hydraulic chamber.
The tappet 16 has a significantly smaller diameter than the borehole 4 at the secondary side. While the relatively close fit between the jacking piston 14 and borehole 4 at the secondary side causes a relatively low leakage flow, the fluid 6 can get from the fluid chamber 9 to the mouth 10 of the borehole 4 at the secondary side without significant throttling.
The piston rod 15 and the tappet 16 are not connected to one another fixedly. Rather, the piston rod 15 is held seated against the tappet 16 by a piston rod spring 26. The piston rod spring 26 is fixed at the piston rod 15 by a device such as a Seeger ring 20, a snap ring, or other similar device. The fact that the piston rod 15 and the tappet 16 are not fixedly connected provides the advantage of a simple installation into the housing 1. An additional advantage is that the influence of pressure peaks in the fluid 6 on the jacking piston 14 is ameliorated. The springing forces at the lifting element 7 are tuned such that, in the neutral state, the sealing element 17, which is designed in the shape of a mushroom valve, closes the mouth 10 against the outside environment from the outside. If, however, a fixedly connected unit of piston rod 15 and tappet 16 is used, then the piston rod spring 26 can be forgone. In this case, a single member, for instance with different diameters of the borehole 4 at the secondary side, can be used instead of the piston rod 15 and the tappet 16.
The present invention further provides a method for the dosed delivery of fluid. In a neutral position, the actuator 12, which is constructed as a piezoactuator, is discharged, or respectively, shorted, so that it has its minimal length in the axial direction and is maximally remote from the borehole 4 at the secondary side. The hydraulic chamber 2 is filled with fluid 6 via the leakage-permitting fit of jacking piston 7 and housing 1. The pressure P in the hydraulic chamber 2 essentially corresponds to the static pressure pending at the feed line 24, typically 25 to 250 bars.
The pressure piston 11 is biased towards the actuator 12 or to the spherical disk 19 thereof, by the readjusting device 13 at the primary side acted on by the pressure P of the fluid 6 in the hydraulic chamber 2. At the same time, the piston rod spring 26 presses the jacking piston 14 away from the hydraulic chamber 2. On the other hand, the forces of the readjusting device 8 at the secondary side--the forces of a spring 21 here--act on the lifting element 7. The resulting forces at the lifting element 7 are so dimensioned that the sealing element 17 closes the borehole 4 at the secondary side against the outside.
At the beginning of a stroking cycle, the actuator 12 is extended in the axial direction, usually 10-60 μm, due to an electrical signal such as a voltage or current signal at terminals 121. Given such a slight shift of the actuator 12, the O-ring 18 does not slide to the wall of the housing 1, but rather is deformed in a purely elastic manner, achieving an advantageous seal.
The actuator 12, attached to the top of the housing 1, presses the pressure piston 11 into the hydraulic chamber 2 with great force via the spherical disk 19, so that the pressure P therein rises. Due to the increased pressure P in the hydraulic chamber 2, fluid 6 drains via the leakage-permitting fit of the jacking piston 14 in the housing 1. The leakage flow, however, is not large enough in relation to the rate of the pressure rise to influence the pressure rise significantly.
Due to the increased pressure P, the force increases and is exerted on the jacking piston 14 and is directed away from the hydraulic chamber 2. When this force component surpasses the force component acting in the opposite direction, the lifting element 7 moves away from the hydraulic chamber 2 and lifts the sealing element 17 from the mouth 10 outwardly. Via the borehole 4 at the secondary side, the fluid 6 flows from the fluid chamber 9, past the tappet 16, and to the mouth 10 and is delivered therefrom into the outside environment in a dosed manner.
The stroke of the jacking piston 14, typically 60 to 360 μm, is limited by a stop 23. The dosing device is thus designed so that, given the stopping of the jacking piston 14, there is still a sufficient reserve of pressure for the lifting element 7 to be open a sufficient amount of time, despite the leaks arising at the hydraulic chamber 2. On the other hand, the leakage is dimensioned to guarantee an automatic return of the lifting element 7 into the neutral position, given an interruption of the electrical terminals 121 in the charged state of the actuator 12.
To return to the neutral position, the stroking process is ended by a contraction of the actuator 12. This can be done by a discharging of the piezoactuator. The mechanically biased cup spring 13 effects readjusting of the pressure piston 11 and the spherical disk 19. Due to the leakage that arose during the actuation period, the pressure P in the hydraulic chamber 2 temporarily drops below the static pressure. This loss of fluid 6 is refilled by a leakage flow from the fluid chamber 9. Upon the relaxing of the pressure P to the static pressure, the lifting element 7 is reset by the spring 21, and the mouth 10 is closed to the outside. This application is particularly advantageous in gasoline direct injection for lean-mix engines. It makes possible the creation of an effectively dosable pilot injection, for example. However, the fluid 6 can be a different liquid besides gasoline, such as diesel, kerosine, oil, methanol, or petroleum, or even a gas, namely natural gas.
The dosing device can be employed resulting in the particular advantage of low pulse/pause ratios (e.g. maximum injection period 1 ms every 24 ms given 5000 rpm in a 4-stroke motor). Relatively long pauses (e.g. 20 ms) guarantee a compensation of the leakages that arise during the short actuation period of the actuator 12 (e.g. 1 ms).
The dosing device illustrated in FIG. 1 has an axially symmetrical structure. Of course, it is possible to deviate from this structure. For example, the dosing device can be constructed from spatially distributed pressure chambers that are connected to one another fluid lines. The individual parts can also be given play. This is done at the expense of functionality, however.
Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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A device and method for dosing fluid has a housing enclosing a lifting element and a primary drive hydraulically operable on the lifting element via a hydraulic chamber. The lifting element is disposed within a borehole with a leakage permitting fit. A fluid chamber in communication with the borehole contains a fluid to be dispensed in a dosed manner by controlled axial movement of the primary drive and lifting element.
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FIELD OF THE INVENTION
[0001] The object of the present invention is a method for processing, by means of an organic solvent containing at least one catalyst, a gaseous effluent containing at least hydrogen sulfide and sulfur dioxide, during which most of the by-products formed during said treating process is removed.
[0002] The by-product removal stage, or processing stage, is notably carried out at a temperature allowing formation and growth of the crystals of these by-products, i.e. crystallization of these by-products.
[0003] The method according to the invention is for example applied in Clauspol processing units used after the Claus process.
BACKGROUND OF THE INVENTION
[0004] The Claus process is widely used, notably in refineries (after hydrodesulfurization or catalytic cracking units) and for processing of natural gas, to recover elemental sulfur from gaseous feeds containing hydrogen sulfide. However, the fumes produced by Claus plants contain, even after several catalytic stages, appreciable amounts of acid gases. It is then necessary to process these Claus plant effluents (tail gas) to remove most of the toxic compounds so as to abide by antipollution standards.
[0005] It is for example well-known to recover about 95% by weight of the sulfur present from a Claus plant.
[0006] Processing this Claus plant effluent with a Clauspol plant allows for example to reach 99.8% by weight of solvent recovered, from the exothermic Claus reaction:
2H 2 S+SO 2 3S+2H 2 O (reaction 1)
[0007] Such processing requires a reaction medium consisting of an organic solvent and at least one catalyst comprising an alkaline or alkaline-earth salt of an organic acid. Contacting the gas to be processed and the organic solvent containing the catalyst is carried out in a gas-liquid contactor reactor whose temperature is controlled by passage of the solvent, that has been extracted from the contactor reactor by a circulation pump, into a heat exchanger so as to favour the highest sulfur conversion coefficient while preventing formation of solid sulfur. It is well-known that, in this type of plant, the solvent that has a limited capacity for dissolving elemental sulfur becomes loaded with free liquid elemental sulfur that can be separated from the solvent by simple decantation. This liquid sulfur—solvent decantation is carried out in a liquid-liquid decantation zone that can be situated at the bottom of the contactor reactor. The sulfur is thus recovered in liquid form.
[0008] Operation of such a plant is for example described in one of the following reference books:
[0009] Y. BARTHEL, H. GRUHIER, The IFP Clauspol 1500 process: eight years of industrial experience, Chem. Eng. Monogr., 10 (Large Chem. Plants), 1979, pp.69-86;
[0010] HENNICO A., BARTHEL Y., BENAYOUN D., DEZAEL C., Clauspol 300: the new IFP TGT process, For presentation at AIChE Summer National Meeting, Denver (Colo.), Aug. 14-17, 1994.
[0011] It is furthermore well-known that the desulfurization rate of a plant of this type can be improved by desaturating the solvent in sulfur in a desaturation loop according to a process described in patent FR-2,735,460 filed by the applicant. In this case, part of the single-phase solvent and sulfur solution extracted at the end of the contactor reactor is cooled in order to crystallize the sulfur. This crystallized sulfur is then separated from the solvent by various known solid-liquid separation means such as filtration, decantation or centrifugation. A sulfur-depleted solvent that can be recycled to the contactor reactor is obtained on the one hand, and a suspension enriched in solid sulfur that can be reheated to melt the sulfur, then sent to a solvent-sulfur liquid-liquid decantation zone where the liquid sulfur is recovered is obtained on the other hand.
[0012] Although such a method proves to be effective, it can however be limited.
[0013] For example, side reactions occur in the contactor reactor, leading to formation of by-products, mainly salts such as alkaline or alkaline-earth sulfates or thiosulfates, due for example to the slow degradation of the catalyst. These by-products tend to accumulate in the decantation zone at the interface between the organic solvent and the liquid sulfur, which makes decantation of the liquid sulfur difficult.
[0014] One way allowing to overcome this problem is described in patent FR-2,735,460, which discloses the possibility of passing a solvent containing such salts through a filter. The salts settle on the filter, and the sulfur-containing solvent is sent to a sulfur-desaturation stage. On the one hand, such processing of the circulating solvent is not sufficient to entirely remove any accumulation of these salts at the liquid sulfur-solvent interface, including the liquid sulfur-solvent decantation zone situated downstream from the zone intended for sulfur desaturation of the solvent. On the other hand, if the solvent is not desaturated in sulfur by means of a desaturation loop, sulfur might be co-eliminated with the solid salts, so that processing of the fluid resulting from regeneration of the filter will be delicate.
SUMMARY OF THE INVENTION
[0015] The object of the present invention is a method and its associated device, wherein a solution extracted from the contactor reactor and containing at least solvent, catalyst, sulfur and by-products is subjected to at least one heating stage and to at least one separation stage so as to remove most of the by-products it contains and to obtain a solvent practically free of said by-products.
[0016] These by-products are for example the result of the slow degradation of the catalyst.
[0017] It has been observed that heating the fluid extracted from the contactor reactor and containing at least solvent, catalyst, sulfur and by-products to a suitable temperature:
[0018] favours crystallization of the by-products in solution in the solvent, which facilitates removal of said by-products,
[0019] causes solubilization of the free sulfur droplets possibly present in the solvent, which prevents co-elimination of sulfur with the by-products and facilitates the possible processing of the fluid resulting from regeneration of elements in the processing zone.
[0020] The solvent practically free of by-products can be advantageously recycled, partly or totally, to the contactor reactor where the gas is processed.
[0021] The invention relates to a method for processing a gas containing at least hydrogen sulfide (H 2 S) and at least sulfur dioxide (SO 2 ), wherein said gas is contacted, at a suitable temperature, with an organic solvent containing at least one catalyst, a gaseous effluent substantially containing no hydrogen sulfide and no sulfur dioxide any more is recovered, as well as liquid sulfur separated from the solvent by liquid-liquid decantation.
[0022] It is characterized in that:
[0023] a fluid F containing at least solvent, catalyst, sulfur and by-products is extracted after the contacting stage,
[0024] said fluid F is sent to a processing stage comprising at least one heating stage during which said fluid F is brought to a determined temperature favouring crystallization of the by-products, and to a stage of separation of the by-products from the solvent,
[0025] after the processing stage, at least a stream F 1 comprising mainly solvent, catalyst and sulfur and nearly free of by-products and a stream F 2 comprising most of the by-products are recovered.
[0026] Fluid F is for example a liquid single-phase solution.
[0027] The by-products contained in fluid F can be dissolved and/or crystallized.
[0028] The temperature to which said fluid F is brought ranges for example between 120 and 180° C., preferably between 120 and 150° C.
[0029] The processing stage is for example carried out by implementing at least one of the following procedures:
[0030] a) carrying out at least one filtering stage so as to recover said fluid F 1 mainly consisting of solvent depleted in solid by-products and said fluid F 2 resulting from regeneration of the filtering support and containing most of the by-products, and/or
[0031] b) carrying out at least one stage of capture, on a solid support, of the by-products so as to recover at least said fluid F 1 mainly consisting of solvent depleted in by-products and said fluid F 2 resulting from regeneration of the solid support and containing most of the by-products.
[0032] Procedures a) and b) can be carried out at a temperature ranging between 120 and 180° C., preferably between 120 and 150° C.
[0033] Fluid F 1 resulting from the processing stage can be recycled, partly or totally, to the contacting stage.
[0034] The invention also relates to a device allowing to remove and to recover by-products formed during a process for treating a gaseous effluent containing at least hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) wherein a solvent and at least one catalyst are used, said device comprising at least one contactor reactor, at least one decantation zone, several lines for delivery of at least the gas to be processed, of the solvent and of the catalyst, several lines for extraction of at least a cleaned gas and of a fluid containing at least solvent, catalyst, sulfur and by-products.
[0035] It is characterized in that it comprises at least one zone for processing said fluid comprising at least solvent, catalyst, sulfur and by-products, said processing zone including heating means suited to favour crystallization of the by-products and by-products—solvent separation means. At the outlet of the processing zone, at least a fluid F 1 mainly consisting of solvent, catalyst and sulfur and nearly free of by-products and a fluid F 2 containing most of the by-products are recovered.
[0036] The heating means are operated for example between 120 and 180° C., preferably between 120 and 150° C.
[0037] According to an embodiment, the decantation zone is situated in the lower part of said contactor reactor.
[0038] The processing zone can comprise at least one of the separation means selected from the following means:
[0039] filtering means, said means being suited to produce at least fluid F 1 mainly consisting of solvent and at least fluid F 2 containing most of the by-products formed, and/or
[0040] capture means such as metals, activated charcoals, zeolites, resins, aluminas, silicas or ceramics, said means being suited to produce at least fluid F 1 mainly consisting of solvent and at least fluid F 2 containing most of the by-products formed.
[0041] The device can comprise a line allowing to recycle at least part of the solvent coming from the processing stage, or fluid F 1 , to the contactor reactor.
[0042] The contactor reactor is for example selected from one of the devices mentioned in the following list: reactor with random or stacked packing or static mixer SMV or impactor or hydro-ejector or atomizer or wire contactor.
[0043] The method and the device according to the invention are for example applied for processing effluents from Claus plants processing the H 2 S coming from natural gas scrubbing operations or from crude oil refining operations.
[0044] The method and its associated device notably afford the following advantages:
[0045] they allow to prevent problems of decantation of the liquid sulfur in the liquid-liquid decantation zone,
[0046] they allow to prevent accumulation of solid by-products in the packings provided in certain contactor reactor types,
[0047] they allow to simply improve existing Clauspol plants by mere addition of a small number of equipments and therefore at a low cost,
[0048] they allow to recover a cleaned solvent and to recycle it directly to the gas treating process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0049] Other features and advantages of the invention will be clear from reading the description hereafter of several embodiments of the method, with reference to the accompanying simplified and non limitative drawings wherein:
[0050] [0050]FIG. 1 is a block diagram of the various elements that constitute the device according to the invention, notably the processing zone,
[0051] [0051]FIG. 2 illustrates a gas processing device comprising a decantation zone situated in the lower part of a contactor reactor,
[0052] [0052]FIG. 3 diagrammatically shows a variant where the processing zone is a filtering zone,
[0053] [0053]FIG. 4 diagrammatically shows a variant where the processing zone is a capture mass, and
[0054] [0054]FIG. 5 shows a diagram from the prior art given by way of comparative example.
DETAILED DESCRIPTION OF THE INVENTION
[0055] The embodiments given hereafter by way of non limitative example relate to the removal of the by-products formed during processing of a gas containing at least hydrogen sulfide and sulfur dioxide. These by-products are notably due to the slow degradation of the catalyst used in the gas treating process.
[0056] According to FIG. 1, the device comprises a gas-liquid contactor reactor 1 . A line 2 supplies the contactor reactor with a sulfur-containing gas feed, for example an effluent from a Claus plant, and a line 3 delivers for example a recycled solution comprising a solvent such as polyethylene glycol 400 and a catalyst such as sodium salicylate.
[0057] Various solvents and catalysts selected from the list given in the description hereafter can be used without departing from the scope of the invention.
[0058] The cleaned gas is discharged through a line 4 .
[0059] A fluid F such as a solvent solution containing at least catalyst, sulfur and by-products formed is discharged from contactor reactor 1 through a line 5 . This solution is then sent through a pump 6 and lines 7 and 13 to a processing zone 14 where it is freed of most of the by-products. Processing zone 14 comprises at least heating means and separation means some of which are shown in detail in FIGS. 3 and 4. The heating means are suited to obtain a temperature favouring crystallization of the by-products in solution in the solvent. Any device known to the man skilled in the art and allowing to obtain and to work at this temperature, notably allowing to reach crystallization of the by-products formed as mentioned above can be used.
[0060] The means for heating the solvent in the processing zone are suited to work within a temperature range between 120 and 180° C., preferably between 120 and 150° C.
[0061] The function of processing zone 14 , comprising means (not shown in this figure) for heating the solvent solution and means (not shown in this figure) for separating the by-products from the solvent, is notably to process solution F containing notably solvent, catalyst, sulfur and by-products, in order to obtain at least a fluid F 2 containing most of the by-products that is discharged through line 19 , and a fluid F 1 consisting mainly of solvent practically totally free of by-products, that is for example recycled through line 15 to contactor reactor 1 .
[0062] Fluid F 1 , in the form OF a liquid single-phase solution nearly free of by-products, is sent through lines 15 and 7 into a heat exchanger 8 where it is cooled to a suitable temperature compatible with operation of contactor reactor 1 , 120° C. for example. This temperature can be controlled by means of a regulator 9 connected to heat exchanger 8 by a line 10 . Line 10 is for example connected to a valve 11 with which a line 12 intended for delivery of the coolant in the heat exchanger is equipped. This cooled solvent solution from heat exchanger 8 can be recycled to contactor reactor 1 through line 3 .
[0063] Fluid F 2 comprising most of the by-products and discharged through line 19 is for example diluted in water prior to being sent to water treatment.
[0064] The liquid sulfur obtained by decantation is discharged through a line 18 situated in the lower part of decantation zone 17 , connected to contactor reactor 1 by a line 16 . Line 18 is provided with a valve V 1 for example.
[0065] the temperature range selected can also allow solubilization of the free sulfur droplets possibly present in the solvent. this has the effect of preventing removal of the sulfur with the by-products formed and of facilitating possible processing of the fluid resulting from regeneration of the elements in the processing zone.
[0066] [0066]FIG. 2 diagrammatically shows a realisation variant where the decantation zone is included in contactor reactor 1 .
[0067] The reference numbers are the same as those used for the identical elements shown in FIG. 1.
[0068] The lower part of contactor reactor 1 comprises a decantation zone 17 ′ provided with a liquid sulfur extraction line 18 , the line being for example equipped with a valve V 1 similar to that shown in FIG. 1.
[0069] Part of the single-phase solvent solution that circulates in the recycle loop (notably consisting of elements 5 , 6 , 7 , 8 , 3 ), for example 10 to 20% of the solution, is for example extracted through a line 40 , from line 7 , in order to be sent to a processing zone such as a zone 41 for desaturating the solvent in sulfur.
[0070] In this desaturation zone 41 , the single-phase solution is cooled, for example to 60° C., in order to form a suspension of sulfur crystals in the solvent. This crystallized sulfur is then separated from the solvent by means of various solid-liquid separation processes known to the man skilled in the art, such as filtering, decantation or centrifugation. A sulfur-depleted solvent is obtained on the one hand and extracted through a line 42 in order to be recycled for example to contactor reactor 1 , and a suspension enriched in solid sulfur is obtained on the other hand. The suspension enriched in solid sulfur can be reheated by appropriate means known to the man skilled in the art in order to melt the sulfur, then sent through a line 43 to the liquid-liquid decantation zone.
[0071] In the various realisation variants given in this description, the operating conditions of the process and of the device can be as follows:
[0072] Contactor reactor 1 can be operated at a temperature ranging for example between 50 and 130° C., preferably between 120 and 122° C. Said sulfur formed is in the liquid form. The liquid sulfur formed is hardly soluble in the solvent and, because of its higher density, it settles in the bottom of the reactor. The water formed is discharged with the cleaned gas. Under such conditions (low temperature and continuous removal of the products formed), equilibrium ( 1 ) is displaced to the right. This temperature is for example controlled by passage of the solvent in heat exchanger 8 .
[0073] The process can be carried out within a very wide pressure range, 9.8 kPa to 4.9 MPa for example. According to an embodiment, it is carried out at the atmospheric pressure.
[0074] The contactor reactor can consist of any equipment or series of equipments allowing contacting of a gas and of a liquid. It can for example be selected from the following list of equipments:
[0075] Reactor with random (Intalox saddles for example) or stacked packing (Mellapak type for example) marketed by the Sulzer company for example,
[0076] Static mixer SMV marketed by the Sulzer company for example,
[0077] Impactor marketed by the AEA company for example,
[0078] Hydro-ejector marketed by the Biotrade company for example,
[0079] Atomizer marketed by the LAB company for example,
[0080] Wire contactor marketed by the Toussaint Nyssenne company for example.
[0081] The solvents commonly used are mono- or poly-alkylene glycols, mono- or poly-alkylene glycol esters or mono- or poly-alkylene glycol ethers, as described in patents FR-2,115,721 (U.S. Pat. No. 3,796,796), FR-2,122,674 and FR-2,138,371 (U.S. Pat. No. 3,832,454).
[0082] the catalysts used are selected from those mentioned in these patents and more particularly alkaline salts of weak organic acids such as benzoic acid and salicylic acid.
[0083] The concentration of the catalyst in the liquid phase advantageously ranges between 0.1 and 5% by weight, more advantageously between 0.5 and 2% by weight.
[0084] The method and the device according to the invention are particularly well-suited for processing a gas whose acid gas content (H 2 S+SO 2 ) ranges between 0.1 and 100% by volume. It is however particularly advantageous for gases having a low acid gas content (H 2 S+SO 2 ), for example between 0.1 and 50% by volume, and more particularly between 0.5 and 5% by volume.
[0085] The separation stage in zone 14 can be performed in various ways, some of which are given hereafter by way of non limitative example.
[0086] Filtering Processing
[0087] According to a variant illustrated in FIG. 3, processing zone 14 comprises heating means 20 and filtration separation means 22 .
[0088] The solvent solution F extracted from contactor reactor 1 through line 5 is sent through pump 6 and lines 7 (FIG. 2) and 13 to processing zone 14 comprising a heat exchanger 20 and filtering means, for example one or more filters 22 , each consisting for example of at least one deformable cloth filter cartridge 23 .
[0089] The solution is heated in heat exchanger 20 to a temperature ranging between 120 and 150° C. in order to favour crystallization of the by-products in solution in the solvent and to solubilize the free sulfur droplets possibly present in the solvent. The solution is then passed into filter 22 where the solid by-products settle on cartridge 23 whereas the cleaned solvent F 1 is extracted through line 15 in order to be recycled to the top of contactor reactor 1 .
[0090] Clearing of cartridge 23 in order to eliminate the deposited solid by-products is for example performed by isolating filter 22 from the rest of the device and by sending into cartridge 23 a fluid such as filtered solvent or water, introduced at a pressure slightly higher than the atmospheric pressure through a line 24 . The clearing operation can be required when the thickness of the cake formed is such that the pressure difference on the filtering cartridge becomes high, for example between 0.1 and 0.4 MPa.
[0091] The by-products in solution in the clearing fluid are extracted from the bottom of the filter through a line 19 .
[0092] The means allowing to isolate processing zone 14 from the rest of the processing circuit are known to the man skilled in the art and are not detailed. They notably include isolating valves V 2 .
[0093] At least a second filter acting as a by-pass filter or parallel to the first one can be provided to ensure continuous filtering of the solvent solution when the first filter is being cleared.
[0094] Capture Processing
[0095] According to a variant illustrated in FIG. 4, separation of the by-products formed is carried out in processing zone 14 by capture on a solid support.
[0096] The solvent solution discharged from contactor reactor 1 through line 5 is sent through pump 6 and lines 7 (FIG. 2) and 13 to processing zone 14 comprising a heat exchanger 20 and capture means, for example one or more capacities 25 comprising each one or more capture beds 26 . The beds consist of solids, for example metals, activated charcoals, zeolites, resins, aluminas, silicas or ceramics.
[0097] The solution is heated in heat exchanger 20 to a temperature ranging between 120 and 150° C. notably in order to favour crystallization of the by-products in solution in the solvent and to solubilize the free sulfur droplets possibly present in the solvent. The solvent solution introduced through line 21 into capacity 25 is passed through collecting bed 26 which traps the by-products. The solvent freed of the most part of the by-products is discharged from capacity 25 through line 15 in order to be recycled to contactor reactor 1 .
[0098] When the bed is saturated with solid by-products, capacity 25 is isolated from the rest of the device and clean water introduced through a line 27 is for example passed through bed 26 . The water is discharged through a line 19 , loaded with dissolved by-products. According to the solid support used, saturation can be controlled either by measuring the pressure drop in the bed or by extrapolating saturation curves obtained in the laboratory.
[0099] As in the case of filtering, the means allowing to isolate processing zone 14 from the rest of the processing circuit are known to the man skilled in the art and will not be detailed. They notably comprise isolating valves V 3 .
[0100] At least a second capacity acting as a by-pass capacity can be provided to allow continuous capture of the by-products contained in the solvent solution during regeneration or replacement of the bed of the first capacity.
[0101] Two numerical examples given hereafter allow to better understand the advantages afforded by the different variants of the method according to the invention.
[0102] In these examples, the term “salt” designates the by-products likely to be formed notably by side reactions because of the presence of the catalyst during a gas treating process.
[0103] The two examples given differ in their method of separation of the by-products and the solvent. In both cases, the contactor reactor is operated as follows:
[0104] A tail gas from a Claus plant is fed through a line 2 , at a flow rate of 12300 Nm 3 /h, into a vertical contactor reactor 1 consisting of a column containing two packing beds, and it is contacted at 125° C. with an organic solvent containing a soluble catalyst introduced through line 3 .
[0105] The packing used in both examples consists of 2 saddle beds (“Intalox” ceramic saddles 250 m 2 /m 3 in specific surface).
[0106] The organic solvent used is a polyethylene glycol with a molecular mass of 400 and the soluble catalyst is sodium salicylate at a concentration of 100 millimoles/kg solvent.
[0107] The solvent is recycled between the bottom and the top of the contactor reactor through lines 5 , 7 and 3 at a flow rate of 500 m 3 /h, by means of circulation pump 6 through a heat exchanger 8 , temperature control and regulation being provided by a measuring and control system 9 , 10 and 11 allowing hot water to be injected at 80° C. into the exchanger through line 12 . The temperature of the recycled solvent is 125° C.
[0108] The cleaned gas flows out of the contactor reactor through line 4 . The sulfur formed settles at the bottom of the contactor reactor and is extracted through line 18 at a rate of 332 kg/h.
[0109] The compositions of the gases flowing into and out of the plant are given in the table hereafter:
Incoming gas (2) Outgoing gas (4) Constituents % vol. % vol. H 2 S 1.234 0.0586 SO 2 0.617 0.0293 CO 2 4.000 4.038 COS 0.015 0.009 CS 2 0.015 0.009 S v * 0.14 0.03 N 2 60 60.396 H 2 O 34 35.384 Sum of the sulfur compounds 2.036 0.1449 (counted in sulfur)
[0110] The sulfur compounds yield in the contactor reactor is:
( % incoming sulfur compounds - % outgoing sulfur compounds ) % incoming sulfur compounds × 100 = ( 2.036 - 0.1449 ) 2.036 × = 92.9 %
[0111] The total yield of the 97% yield Claus plant+Clauspol finishing plant is:
97 + ( 3 × 92.9 ) 100 = 99.8 %
[0112] The solution F extracted through line 5 is processed by filtering or capture in processing zone 14 according to the two procedures described hereafter.
EXAMPLE 1
(FIGS. 2 and 3 ): Filtration Separation
[0113] Heat exchanger 20 allows to heat the solvent solution to 135° C. and a filter 22 consisting of three 1-m 2 surface cartridges 23 allows to separate the two fluids F 1 and F 2 . Clearing is performed by isolating processing zone 14 from the rest of the device and by sending water under slight pressure into the cartridges through line 24 when the thickness of the cake exceeds 3 mm, i.e. when the pressure difference on the filtering cartridges becomes greater than 0.2 MPa. After clearing, the salts are recovered in solution in the water at the bottom of the filter and sent to water treatment through line 19 . The filter is cleared about every 12 h.
EXAMPLE 3
(FIGS. 2 and 4 ): Capture Separation
[0114] In this example, heat exchanger 20 allows to heat the solvent solution to 135° C. and a capacity 25 containing two 1-m 3 salt capture beds 26 , each made of a material having a good affinity with the salts to be collected, ceramic saddles for example, allows to separate fluids F 1 and F 2 . After one month of continuous running, the pressure drop becomes higher than 7 kPa, which indicates that the beds are saturated with salts. The processing zone is then isolated from the rest of the device and the capture beds are regenerated by washing with water introduced clean through line 27 and discharged loaded with salts through line 19 prior to being sent to water treatment.
[0115] [0115]FIG. 5 diagrammatically shows the process according to the prior art wherein fluid F, or single-phase solution containing mainly solvent, catalyst, sulfur and by-products, is extracted through line 5 and directly sent into a heat exchanger 30 similar to exchanger 8 , prior to being recycled to the contactor reactor. Temperature control is performed in the same way as in FIG. 1, with a regulator 9 connected to heat exchanger 30 by a line 10 , the coolant being delivered through a line 12 equipped with a valve 11 and discharged through a line 13 .
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A method for processing a gas containing at least hydrogen sulfide (H 2 S) and at least sulfur dioxide (SO 2 ), includes the steps of contacting the gas with a liquid solvent containing at least one catalyst in a contacting stage, recovering gaseous effluent substantially containing no hydrogen sulfide and no sulfur dioxide from the contacting stage, and separating liquid sulfur from liquid solvent in a decantation zone downstream of the contacting stage. In order to remove by-products resulting from degradation of the catalyst, a liquid fraction F containing at least solvent, catalyst, sulfur and the solid by-products resulting from degradation of the catalyst is extracted from after the contacting stage. The liquid fraction F is sent to a processing stage distinct from the contacting stage where the liquid fraction F is heated to a temperature at least partially crystallizing the by-products, and the at least partially crystallized by-products separated from the rest of the liquid fraction F containing at least solvent. At least a stream F 1 comprising solvent, catalyst and sulfur and substantially free of the by-products and a stream F 2 mostly comprising the by-products are recovered.
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FIELD OF THE INVENTION
The invention relates to snowplow assemblies, and more particularly, to snowplow assemblies that are removably mounted to a vehicle.
BACKGROUND OF THE INVENTION
Snowplows that are mounted to vehicles such as automobiles and light trucks are customarily attached to the vehicle frame. Most often the vehicle frame is only accessible from underneath the vehicle and it is often necessary to reach under the vehicle in order to attach the snowplow to the frame. Typically, a bracket is fixedly attached to the vehicle frame and the snowplow is attached to the bracket with one or more fasteners.
Many arrangements have been devised using fasteners and brackets in order to facilitate connection of the snowplow to the vehicle. Many such devices inconvenience the user by requiring the user to reach underneath the vehicle in order to connect or disconnect the snowplow from the vehicle. This is especially inconvenient during the winter, and in the snowy or dirty conditions in which the snowplow is ordinarily used.
SUMMARY OF THE INVENTION
The present invention is a vehicle mountable snowplow that can be removably attached to a vehicle in a relatively quick and convenient fashion. The snowplow can be connected to and disconnected from the vehicle without having the user reach underneath the vehicle. The snowplow is not only easily attached to and detached from the vehicle, the snowplow is also stable and secure during use.
Specifically, the present invention provides a snowplow for selective attachment to a vehicle. The snowplow includes a plow frame, a blade attached to the plow frame, and at least one latching mechanism on the plow frame. The latching mechanism is movable to a first position wherein the plow frame is engaged with the vehicle, and is also movable from the first position to a second position wherein the plow frame is disengaged from the vehicle.
The latching mechanism includes a hitch member that is movable with respect to the plow mount. The hitch member has thereon a hitch pin. When the latching mechanism is in it first position, the hitch pin interengages with the vehicle. Preferably, the hitch member includes a first arm, a second arm secured to the first arm, and a third arm secured to the second arm, wherein the second arm is movably secured to the frame.
The invention further provides a lock to maintain the latching mechanism in its first position. The lock includes a locking pin on the plow frame.
Such a snowplow provides the feature of a latching mechanism that is actuated by the user to engage and disengage the snowplow from the vehicle at a point remote from the vehicle. The hitch member extends beyond the vehicle, thereby allowing remote operation of the latching mechanism. In this way, the snowplow can be selectively attached and detached from the vehicle using a simple and convenient motion.
It is an object of the present invention to provide a new and improved vehicle mountable snowplow assembly.
It is another object of the present invention to provide a snowplow assembly that may be quickly and simply connected and disconnected from a vehicle.
It is another object of the present invention to provide a snowplow assembly that includes a hitch member that extends beyond the vehicle, and is movable from a point remote from the vehicle.
It is another object of the present invention to provide a locking mechanism to maintain the snowplow in its engaged or disengaged position relative to the vehicle.
It is another object of the present invention to provide a hitch member having a first arm, a second arm, and a third arm, wherein the second arm is pivotally secured to the frame of the snowplow, and the first arm extends beyond the vehicle.
It is another object of the present invention to provide an apparatus that selectively secures a snowplow to a vehicle, and includes a vehicle mount and a plow mount.
Other features and advantages of the invention will become apparent to those of ordinary skill in the art upon review of the following detailed description, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a vehicle mountable snowplow assembly in position for mounting to a vehicle mount of a vehicle;
FIG. 2 is a top view of a portion of the snowplow assembly and a portion of the vehicle;
FIG. 3 is a perspective view of a latching mechanism mounted on the plow mount;
FIG. 4 is perspective view, partially exploded, of the latching mechanism mounted on the plow mount;
FIG. 5 is a perspective view of the vehicle mount;
FIG. 6 is a perspective view of the vehicle mount fixed to a portion of the vehicle;
FIG. 7 is a top view of the latching mechanism in its engaged or first position;
FIG. 8 is a top view of the latching mechanism in its disengaged or second position; and
FIG. 9 is an exploded perspective view of a locking pin.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, FIG. 1 shows a snowplow assembly 10 according to the present invention. As indicated by the arrows, the snowplow assembly 10 may be moved into position such that it may be selectively attached or connected to a vehicle 12 (solid arrows) and may subsequently be detached or disconnected from the vehicle 12 (broken arrows). Snowplow assembly 10 can be any type of vehicle mountable snowplow such as the snowplow illustrated and described in U.S. application Ser. No. 08/938,004, filed Sep. 12, 1997, entitled "Vehicle Mounted Accessory Assembly" and herein incorporated by reference.
As illustrated in FIG. 1, the snowplow assembly 10 generally includes a frame 14 and a blade 16 attached to the forward end of the frame 14. The snowplow assembly 10 also includes a pair of hitch assemblies or latching mechanisms 18a and 18b (hereafter collectively 18) as shown in FIG. 2. The latching mechanisms 18 enable the connection to and disconnection of the snowplow assembly 10 from the vehicle 12. The latching mechanisms 18 interconnect the snowplow assembly 10 to the vehicle 12 and, specifically, to a mount member or vehicle mount 20 fixed to the vehicle 12.
Referring now to FIGS. 1 and 2, preferably the latching mechanisms 18 are mounted to an intermediate member or plow mount 22 and the plow mount 22 in turn is secured to the frame 14. It should be noted, however, that the latching mechanisms 18 can also be mounted directly to the frame 14 without the use of the plow mount 22.
As best shown in FIG. 2, the plow mount 22 includes a pair of generally parallel spaced mount arms 24 and 26 that are connected by a mount brace 28 so that the plow mount 22 is generally U-shaped. The mount arms 24 and 26 are fixedly secured to the mount brace 28 such as by welding. A gusset brace 30 is positioned and secured in each of the intersections of the mount arms 24 and 26 to the mount brace 28 to add structural support to the plow mount 22.
As best shown in FIG. 4, preferably the mount arms 24 and 26 and the mount brace 28 are hollow metal tubes that are square in cross-section and have an interior. The mount brace 28 includes a recess such as hollow end 32 and hollow end 34. Each mount arm 24 and 26 has a hollow end 36. A cap 38 is positioned in the hollow end 36 of each of the mount arms 24 and 26. Each cap 38 serves as a protective covering for a grease fitting and serves as an anti-friction surface during connection of the plow mount 22 to the vehicle 12.
Continuing to refer to FIG. 4, a bushing 42 is mounted in each mount arm 24 and 26. Preferably, the bushing 42 is fixed in the respective mount arm 24 or 26 such as by welding. Each bushing 42 defines a cylindrical passageway or bore 40 therethrough. For example, the bore 40 has a diameter D1 that is 0.75 inches.
A pair of mounting brackets 44 extend perpendicularly outwardly from the mounting brace 28 in a direction away from the mount arms 24 and 26. Each mounting bracket 44 is fixedly secured to the mounting brace 28 such as by welding. Each bracket 44 has therein an aperture 46. As shown in FIGS. 1 and 2, the plow mount 22 is secured to the frame 14 with the mounting brackets 44. When the plow mount 22 is aligned with the frame 14, a fastener, such as a bolt, can be positioned in the aperture 46 of each of the brackets 44 to secure the plow mount 22 to the frame 14. Preferably, at assembly, a second aperture is drilled in each bracket 44 and an aligned aperture is drilled in the frame 14 with a fastener being positioned in the aligned apertures. This second connection of the brackets 44 to the frame 14 prevents rotation of the plow mount 22.
Referring back to FIG. 2, preferably, the snowplow assembly 10 includes a latching mechanism 18a in operational engagement with the mount arm 24 and a latching mechanism 18b in operational engagement with the mount arm 26. The latching mechanisms 18a and 18b are preferably operationally identical and mirror images of each other. Hereafter, only one latching mechanism 18a in relation to mount arm 24 will be described.
As best shown in FIGS. 3 and 4, the latching mechanism 18a includes link arm 48. The link arm 48 is comprised of a first portion 50 and a second portion 52 that are generally C-shaped and are oriented to surround the mount arm 24. The first and second portions 50 and 52 respectively each have therethrough an aperture 54 that is axially aligned. The link arm 48 is pivotally secured to mount arm 24 with a pivot pin 56 that is positioned and secured in each of the apertures 54.
A hitch arm 58 extends outwardly from the link arm 48 and, specifically, extends outwardly from one of the intersections of the first portion 50 and the second portion 52. The hitch arm 58 is secured in this orientation such as by welding. The hitch arm 58 forms an angle A (FIG. 2) of preferably approximately 120 degrees with respect to the link arm 48. The hitch arm 58 terminates in an end 60. The hitch arm 58 is elongate and preferably has a length that is approximately equal to the distance between the link arm 48 and the mount brace 28.
Continuing to refer to FIGS. 3 and 4, a link arm 64 extends outwardly from the link arm 48 and specifically, extends outwardly from the other of the intersections of the first portion 50 and the second portion 52. The link arm 64 is secured in this orientation such as by welding. The link arm 64 forms an angle B (FIG. 2) of preferably approximately 120 degrees with respect to the link arm 48. The link arm 64 terminates in an end 66. The link arm 64 includes an elongate slot 68 adjacent the end 66. The link arm 64 preferably has a length that is approximately equal to the distance between the link arm 48 and the bore 40 in the mount arm 24.
Preferably, the link arms 48, 58 and 64 are interconnected to form a hitch member that pivots about mount arm 64.
As best shown in FIG. 4, a pin assembly 70 is in operation engagement with the link arm 64. The pin assembly 70 includes a mounting clevis 72 which includes a first leg 74 and a second leg 76. Each leg 74 and 76 has therethrough an axially aligned aperture 78. The clevis 72 is fixedly secured to a hitch pin 80. The pin 80 can having any number of cross-sectional configurations including, for example, cylindrical, triangular, square, rectangular, hexagonal or the like. The pin 80 is preferably stepped and includes a first portion 82 having a cross-section or diameter D2 and a second portion 84 having a cross-section or diameter D3. The pin 80 terminates in a tapered tip 86. D3 is preferably smaller than D2. For example, D2 is 0.735 inches and D3 is 0.625 inches.
With reference to FIG. 4, the pin assembly 70 is movably secured to the link arm 64 with a fastener such as a pin 88. To assemble the pin assembly 70 about the link arm 64, the link arm 64 is placed between the legs 74 and 76 of the clevis 72 such that the apertures 78 of the legs 74 and 76 and the slot 68 of the link arm 68 are axially aligned. The pin 88 is then positioned in the axially aligned apertures 78 and slot 68 and maintained in this orientation such as with a cotter pin.
In this orientation, the pin 88 is slidable along the length of the slot 68. When the pin assembly 70 is so oriented, the hitch pin 80 is housed and moveable within the bore 40. Movement of the hitch arm 58 moves the pin 80 within the bore 40. Having the pin 80 remain contained yet moveable within the bore 40 prevents the pin 80 from getting lost or misaligned. This orientation also requires less pin movement to secure the snowplow assembly 10 to the vehicle 12.
Turning now to FIGS. 7 and 8, both latching mechanisms 18a and 18b are moveable between a first or engaged position as shown in FIG. 7 and a second or disengaged position as shown in FIG. 8.
With specific reference to FIG. 7 and latching mechanism 18b, when the latching mechanism 18b is in its first or engaged position: (i) the tip 86 and the second portion 84 of the pin 80 extend outwardly from the bore 40 of the mount arm 26; (ii) the hitch arm 58 is adjacent to and approximately parallel to the mount arm 26; and (iii) the pin 88 is at the end of the slot 68 adjacent the link arm 48 such that the link arm 64 forms an angle C of approximately 106 degrees with the longitudinal axis of the pin 80.
With specific reference now to FIG. 8, when the latching mechanism 18 is in its second or disengaged position: (i) the tip 86 and the second portion 84 of the pin 80 are housed within the bore 40 and do not extend outwardly from the mount arm 26; (ii) the hitch arm 58 is no longer parallel to the mount arm 26; and (iii) the pin 88 is at the other end of the slot 68 adjacent the pin 80 such that the link arm 64 is approximately perpendicular to the longitudinal axis of the pin 80.
The use of the pin 88 and slot 68 arrangement enables easier translation of the movement of the hitch arm 58 to the pin 80 within the bore 40. Designing the hitch arm 64 orientation such that the hitch arm 64 is generally perpendicular to the pin 80 when the latching mechanism 18 is in its disengaged position, and such that the hitch arm 64 is at an angle with respect to the pin 80 when the latching mechanism 18 is in its engaged position, further enables easier translation of the movement of the hitch arm 58 to the pin 80 within the bore 40. Specifically, movement of the hitch arm 58 toward the respective mount arm 26 causes the link arm 64 to apply a force to pin 80, with that force being in line with the longitudinal axis of the pin 80 thereby enabling the translation of a more fluid motion of the pin 80 within the bore 40.
Turning now to FIGS. 5 and 6, the vehicle mount 20 is illustrated. The vehicle mount 20 includes an elongate body 90, a pair of vehicle mounting brackets 92 and a pair of vehicle mounting brackets 94. One bracket 92 and one bracket 94 are adjacent each end of the body 90. The bracket 92 has therein an aperture 96. The bracket 94 is generally L-shaped and has therein apertures 98 and 100.
As shown in FIG. 6, the vehicle mount 20 is secured to the vehicle 12, and preferably to the frame of the vehicle 12, using the pairs of vehicle mounting brackets 94 and 96. Specifically, the aperture 100 is aligned with a preexisting or drilled aperture in the vehicle frame and a suitable fastener is positioned therethrough. With respect to apertures 96 and 98, they are preferably drilled at assembly to be aligned with apertures in the vehicle frame which are also preferably drilled at assembly. Fasteners are thereafter positioned in the apertures 96 and 98 and the respective apertures in the vehicle frame to maintain the orientation of the vehicle mount 20 to the vehicle 12.
It should be noted that vehicle mount 20 can have varying configurations to be suitable for attachment to different vehicles. Further, how the vehicle mount 20 is attached to the vehicle can also vary depending upon the type of vehicle to which the mount 20 is to be attached.
With respect to where the vehicle mount 20 is located, preferably, the mount 20 is positioned near the front axle of the vehicle 12 so as to be a distance from the vehicle bumper under the vehicle 12. Having the vehicle mount 20 so positioned enhances the aesthetics of the vehicle 12 because the vehicle mount 20 cannot be seen at normal eye level. Further, this positioning of the vehicle mount 20 also improves the crash worthiness of the vehicle 12.
With the use of the plow mount 22 separating the frame 14 from the vehicle 12, the vehicle bumper does not limit the range of motion of the snowplow blade 16. Further, with the use of the plow mount 22, less stresses are transferred to the vehicle 12. The orientation of the vehicle mount 20, the plow mount 22 and the frame 14 as shown in FIG. 1 eliminates any downward forces the snowplow would exert on the vehicle 12 and instead exerts a slight upward force to the vehicle 12.
As best shown in FIGS. 2 and 6, the vehicle mount 20 further includes a pair of spaced locking assemblies 106. The locking assemblies 106 are spaced from one another approximately the distance that the mount arms 24 and 26 are spaced from one another. Each locking assembly 106 includes a plate 108 and a plate 110. The plate 108 includes a first portion 114 and a second portion 116, with the second portion 116 being flared at an angle of preferably 45 degrees with respect to the first portion 114. The first portion 114 has therethrough an aperture 118. The first portion 114 is generally parallel to the plate 110.
The plate 110 has therein a generally V-shaped recess 120 that terminates in a semi-circular recess 122. The recess 122 is axially aligned with the aperture 118 in the plate 108. The plates 108 and 110 define therebetween a locking channel 124.
The snowplow assembly 10 is connected to and released from the vehicle 12 as follows. With reference to FIG. 1, the snowplow assembly 10 is positioned adjacent the vehicle 12 and vehicle mount 20 such that the mount arms 24 and 26 are generally aligned with their respective locking channel 124. The snowplow assembly 10 is moved further in the direction of the vehicle 12 until the first portion 82 of the hitch pin 80 is positioned in the recess 122 and contacts the plate 110 as shown in FIG. 2. As the mount arm 24 enters the locking channel 124, the mount arm 24 with pin assembly 70 extending outwardly is able to continue to move forwardly because of the recesses 120 and 122.
The locking assemblies 106 are designed such that if the mount arms 24 and 26 are not perfectly aligned as they move toward the locking channels 124, the second flared portion 116 acts to guide the respective mount arm 24 or 26 into the locking channel 124. The cap 38 having a smooth outer surface also aids in sliding the mount arms 24 and 26 into a respective locking channel 124.
Referring now to FIG. 2, the latching mechanism 18 on each of the mount arms 24 and 26 is then actuated as follows. The pins 80 of each latching mechanism 18a and 18b are already axially aligned with the respective aperture 118 in the plate 108. This orientation is enabled due to the recesses 120 and 122 in the plate 110. With respect to mount arm 24 and latching mechanism 18a, the hitch arm 58 is moved toward the mount arm 24 as illustrated by the solid arrow. Movement of the hitch member 58 pivots the link arm 48 about the pivot pin 56 which in turn moves the pin 80 toward the plate 108 as illustrated by another solid arrow in FIG. 2. The pin 80 moves within the bore 92 of the mount arm 24 such that the second portion 84 of the pin 80 enters and is housed in the aperture 118 of the plate 108. When the pin 80 is housed in aperture 118, the latching mechanism 18a is in its first or engaged position such that the snowplow assembly 10 is secured to the vehicle 12.
Latching mechanism 18b is similarly actuated from its second or disengaged position to its first or engaged position with respect to mount arm 26.
To maintain the latching mechanisms 18a and 18b in their engaged positions, many types of releasable fasteners can be employed, such as removably securing both hitch arms 58 to the respective mount arm 24 or 26. However, preferably a locking mechanism is employed.
With reference to FIG. 3, a locking mechanism 126 for each latching mechanism 18a and 18b is shown. The locking mechanisms 126 are preferably identical and mirror images of each other. Accordingly, only the locking mechanism 126 used in conjunction with latching mechanism 18a with be hereafter described.
The locking mechanism 126 includes a link arm 128 extending generally perpendicularly outwardly from the hitch arm 58 in a direction toward the mount arm 24. The link arm 128 is secured to the hitch arm 58 such as by welding. The link arm 128 includes a first portion 132 and a second ramp portion 134. The first portion 132 has therein an aperture 136. The ramp portion 134 is angled downwardly with respect to the first portion 132 by an angle of preferably 30 degrees. The link arm 128 is positioned relative to the hitch arm 58 such that movement of the hitch arm 58 toward the mount arm 24 moves the link arm 128 into the interior of the mount brace 28 via the hollow end 32. The link arm 128 is releasably held within the mount brace 28 by a locking pin 138.
Turning now to FIG. 9, the locking pin 138 is illustrated. The locking pin 138 includes a lock body 140 having a hexagonal shaped cap 142 and a hollow cylindrical portion 144. A plunger 146 is housed within the cylindrical portion 144. The plunger 146 includes a shaft 148 having therethrough a bore 150. The shaft 148 terminates at one end in a hexagonal cap 152. A spring 154 surrounds the shaft 148 and is likewise housed within the cylindrical portion 144. The plunger 146 and spring 154 are housed in the cylindrical portion 144 such that the end of the shaft 148 having the bore 150 therethrough is moveable through an aperture 158 within the cap 142 of the lock body 140.
With the aperture 150 extending outwardly from the cap 142 through the aperture 158, a split ring 160 is positioned within the bore 150 of the shaft 148. Movement of the split ring 160 away from the cap 142 by a user overcomes the bias of the spring 154 and moves the plunger 146 upwardly into the cylindrical portion 144. When the user releases the split ring 160, the bias of the spring 154 returns the plunger 146 to its normal portion, that being extending outwardly from the cylindrical portion 144.
With reference to FIG. 4, each locking pin 138 is mounted in a respective aperture 162 in the mounting brace 28 such that the cylindrical portion 144 extends into the interior of the mount brace 28 and the cap 142 abuts the top surface of the mount brace 28. The locking pin 138 is held in this orientation through use of a fastener such as nut 164.
To secure the latching mechanism 18a in its first or engaged position, the hitch arm 58 is swung so that the link arm 128 begins to move into the interior of the mount brace 28 at the end 32. Further movement of the link arm 128 forces the plunger 146 upwardly due to the plunger 146 abutting the ramp portion 134 of the link arm 128 and overcoming the force of the spring 154. Continued movement of the link arm 168 into the interior of the mount brace 28 will eventually cause the plunger 146 to move downwardly via spring 154 action when the plunger 146 is aligned with aperture 136 in the link arm 168. With the plunger 146 in the aperture 136, the hitch arm 58 is held in place. The ramp portion 134 serves to automatically actuate the locking pin 138 without the user having to manually pull up on the split ring 160 of the locking pin 138. The movement of the link arm 128 into the interior of the mount brace 28 by the user automatically actuates the locking pin 138 to hold the latching mechanism 18a in its engaged position.
In addition to the ramp portion 134 aiding the alignment and actuation of the plunger 146 in the aperture 136, the ramp portion 134 also serves to prevent the plunger 146 from becoming inadvertently dislodged from the aperture 136. Specifically, the ramp portion 134 serves to minimize the range of movement of the link arm 128 in the mount brace 28. If a downward force is applied to link arm 128, before the link arm 128 can move downwardly enough to free the plunger 146 from the aperture 136, the ramp portion 134 will abut the bottom surface of the interior.
It should be noted that movement of the hitch arm 58 actuates both the latching action of the pin 80 as well as the locking action of locking pin 138.
To release or disengage the snowplow assembly 10 from the vehicle 12, the split ring 160 of the locking pin 138 is moved upwardly by the user thus freeing the plunger 146 from the aperture 136. The hitch arm 58 associated with each mount arm 24 and 26 can then be moved outwardly from the respective mount arm 24 and 26 as illustrated by the broken arrows in FIG. 2. Such movement of the hitch arms 58 retracts the second portion 86 of the pin 80 from the aperture 118 of the plate 108 thus freeing the snowplow assembly 10 from the vehicle 12. It should be noted, in this unlocked position, the pin 80 remains partially housed in the bore.
The locking mechanism 126 also serves as a fail safe. If the hitch pin 80 is obstructed and cannot move into its fully engaged position, i.e. second portion 84 and tip 86 extending outwardly from the bore 40, the hitch arm 58 cannot be locked because the link arm 128 will not have entered the interior of the mount brace 28.
It should be noted that the locking pin 138 can be used in other locking applications on snowplow assemblies such as to releasably hold components in place such as stands and light assemblies.
As shown in FIG. 2, the hitch arms 58 extend beyond the broken outline of the vehicle 12. The plow mount 22 can therefore be secured and released from the vehicle 12 at a point remote from the vehicle 12. In this way, the user can engage or disengage the snowplow assembly 10 from the vehicle 12 without having to reach underneath the vehicle 12.
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A snowplow for selective attachment to a vehicle, comprising a frame, a blade attached to the frame, and a latching mechanism that is movable to first and second positions to allow selective engagement or disengagement of the snowplow with the vehicle. The latching mechanism is operable by a user from a location point remote from underneath the vehicle.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part application of U.S. patent application Ser. No. 08/407,756, filed on Mar. 21, 1995, now U.S. Pat. No. ______.
[0002] This invention was made with government support under U01 CA52956 awarded by the National Cancer Institute. The government has certain rights in the invention.
FIELD OF THE INVENTION
[0003] This invention relates to compositions and methods of selectively inhibiting tumors and, more particularly, to treating a malignant melanoma using plant-derived compounds and derivatives thereof.
BACKGROUND OF THE INVENTION
[0004] Over the past four decades the incidence of melanoma has been increasing at a higher rate than any other type of cancer. It is now theorized that one in 90 American Caucasians will develop malignant melanoma in their lifetime. While an increasing proportion of melanomas are diagnosed sufficiently early to respond to surgical treatment and achieve a greater than 90% ten-year survival rate, it is estimated that nearly 7,000 individuals suffering from metastatic melanoma will die in the United States this year.
[0005] For patients with metastatic melanoma not amenable to surgical extirpation, treatment options are limited. 5-(3,3-Dimethyl-1-triazenyl)-1-H-imidazole-4-carboxamide (dacarbazine, DTIC) is the most efficacious single chemotherapeutic agent for melanoma having an overall response rate of 24%. But the duration of response to DTIC is generally quite poor. Combination therapy with other synthetic and recombinant agents, including N,N′-bis(2-chloroethyl)-N-nitrosurea (carmustine, BCNU), cisplatin, tamoxifen, interferon-alpha (INF-α) and interleukin-2 (IL-2), has a higher response rate (e.g., 30-50%) in some trials, but a durable complete response rate is uncommon and toxicity is increased. Sequential chemotherapy has promise, but, clearly, current treatment options for individuals suffering from metastatic melanoma are unsatisfactory.
[0006] Various drugs derived from natural products, such as adriamycin (doxorubicin) derivatives, bleomycin, etoposide, and vincristine, and their derivatives, have been tested for efficacy against melanoma either as single agents or in combination therapy. However, similar to the synthetic and recombinant compounds, these compounds exhibit low response rates, transient complete responses, and high toxicities.
[0007] Nonetheless, as demonstrated by known and presently-used cancer chemotherapeutic agents, plant-derived natural products are a proven source of effective drugs. Two such useful natural product drugs are paclitaxel (taxol) and camptothecin. Paclitaxel originally derived from the bark of the Pacific yew tree Taxus brevifolia Nutt. (Taxaceae), currently is used for the treatment of refractory or residual ovarian cancer. More recently, clinical trials have been performed to investigate the possible role of paclitaxel in the treatment of metastatic melanoma. As a single agent, taxol displays activity comparable to cisplatin and IL-2. Taxol functions by a unique mode of action, and promotes the polymerization of tubulin. Thus, the antitumor response mediated by taxol is due to its antimitotic activity. The second drug of prominence, camptothecin, was isolated from the stem bark of a Chinese tree, Camptotheca acuminata Decaisne (Nyssaceae). Camptothecin also functions by a novel mechanism of action, i.e., the inhibition of topoisomerase I. Phase II trials of a water-soluble camptothecin pro-drug analog, Irinotican (CPT-11), have been completed in Japan against a variety of tumors with response rates ranging from 0% (lymphoma) to 50% (small cell lung). Topotecan, another water-soluble camptothecin analog, currently is undergoing Phase II clinical trials in the United States.
[0008] Previous antitumor data from various animal models utilizing betulinic acid have been extremely variable and apparently inconsistent. For example, betulinic acid was reported to demonstrate dose-dependent activity against the Walker 256 murine carcinosarcoma tumor system at dose levels of 300 and 500 mg/kg (milligrams per kilogram) body weight. In contrast, a subsequent report indicated the compound was inactive in the Walker 256 (400 mg/kg) and in the L1210 murine lymphocytic leukemia (200 mg/kg) models. Tests conducted at the National Cancer Institute confirmed these negative data.
[0009] Similarly, antitumor activity of betulinic acid in the P-388 murine lymphocyte test system has been suggested. However, activity was not supported by tests conducted by the National Cancer Institute. More recently, betulinic acid was shown to block phorbol ester-induced inflammation and epidermal ornithine decarboxylase accumulation in the mouse ear model. Consistent with these observations, the carcinogenic response in the two-stage mouse skin model was inhibited. Thus, some weak indications of antitumor activity by betulinic acid have been reported, but, until the present invention, no previous reports or data suggested that betulinic acid was useful for the selective control or treatment of human melanoma. Furthermore, to date, no information has been published with respect to the selective activity of derivatives of betulinic acid against melanoma cells.
SUMMARY OF THE INVENTION
[0010] The present invention is directed to a method and composition for preventing or inhibiting tumor growth. The active compound is betulinic acid or a derivative of betulinic acid. The betulinic acid is isolated by a method comprising the steps of preparing an extract from the stem bark of Ziziphus mauritiana and isolating the betulinic acid. Alternatively, betulin can be isolated from the extract and used as precursor for betulinic acid, which is prepared from betulin by a series of synthetic steps. The betulinic acid can be isolated from the extract by mediating a selective cytotoxic profile against human melanoma in a subject panel of human cancer cell lines, conducting a bioassay-directed fractionation based on the profile of biological activity using cultured human melanoma cells (MEL-2) as the monitor, and obtaining betulinic acid therefrom as the active compound. The resulting betulinic acid can be used to prevent or inhibit tumor growth, or can be converted to a derivative to prevent or inhibit tumor growth.
[0011] An important aspect of the present invention, therefore, is to provide a method and composition for preventing or inhibiting tumor growth and, particularly, for preventing or inhibiting the growth of melanoma using a natural product-derived compound, or a derivative thereof.
[0012] Another aspect of the present invention is to provide a treatment method using betulinic acid to prevent the growth or spread of cancerous cells, wherein the betulinic acid, or a derivative thereof, is applied in a topical preparation.
[0013] Another aspect of the present invention is to overcome the problem of high mammalian toxicity associated with synthetic anticancer agents by using a natural product-derived compound, e.g., betulinic acid or a derivative thereof.
[0014] Still another aspect of the present invention is to overcome the problem of insufficient availability associated with synthetic anticancer agents by utilizing readily available, and naturally occurring betulinic acid, or a derivative thereof.
[0015] Yet another aspect of the present invention is to prepare derivatives of betulinic acid that have a highly selective activity against melanoma cells, and that have physical properties that make the derivatives easier to incorporate into topical preparations useful for the prevention or inhibition of melanoma cell growth.
[0016] These and other aspects of the present invention will become apparent from the following description of the invention, which are intended to limit neither the spirit or scope of the invention but are only offered as illustrations of the preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] [0017]FIG. 1 is a plot of mean tumor volume (in cubic centimeters (cm 3 )) vs. time for nonestablished MEL-2 tumors in control mice and mice treated with increasing dosages of betulinic acid;
[0018] [0018]FIG. 2 is a plot of mean tumor volume (in cm 3 ) vs. time for established MEL-2 tumors in control mice and mice treated with DTIC or betulinic acid;
[0019] [0019]FIG. 3(A) is a plot of the 50 Kbp (kilobase pairs) band as % total DNA v. time for treatment of MEL-2 cells with 2 μg/ml (micrograms per milliliter) betulinic acid;
[0020] [0020]FIG. 3(B) is a plot of the 50 Kbp band as % total DNA versus concentration of betulinic acid (μg/ml); and
[0021] [0021]FIGS. 4 and 5 are plots of mean tumor volume (cm 3 ) vs. time for established and nonestablished MEL-1 tumors in control mice and mice treated with increasing doses of betulinic acid.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Betulinic acid, 3β-hydroxy-lup-20(29)-ene-28-oic acid, is a natural product isolated from several genus of higher plants. Through a bioassay-directed fractionation of the stem bark of Ziziphus mauritiana Lam. (Rhamnaceae), betulinic acid, a pentacyclic triterpene, was isolated as an active compound that showed a selective cytotoxicity against cultured human melanoma cells. The cell lines evaluated for cytotoxicity were A431 (squamous), BC-1 (breast), COL-2 (colon), HT-1080 (sarcoma), KB (human oral epidermoid carcinoma), LNCaP (prostate), LU-1 (lung), U373 (glioma), and MEL-1, -2, -3, and -4 (melanoma). Betulinic acid was found to be an excellent antitumor compound against human melanoma due to its unique in vitro and in vivo cytotoxicity profile. Betulinic acid has shown a strong selective antitumor activity against melanoma by induction of apoptosis. The selective cytotoxicity of betulinic acid, and its lack of toxicity toward normal cells, afford a favorable therapeutic index. In addition, betulinic acid has been reported to have an anti-HIV activity.
[0023] The bark of white birch, Betula alba, contains betulin (up to about 25&), lup-20(29)-ene-3β,28-diol, and betulinic acid (0.025%), but it is difficult to isolate a sufficient quantity of betulinic acid to perform an extensive bioassay. It has been found that a quantity of betulinic acid could be provided from betulin through a simple synthetic approach. A number of multi-step synthetic conversions of betulin to betulinic acid have been reported, but these synthetic sequences suffer from a low overall yield. A concise two-step conversion of betulin to betulinic acid, in good yield, has been reported in Synthetic Communications, 27(9), pp. 1607-1612 (1997).
[0024] As shown in Table 1, in vitro growth of MEL-2 cells was inhibited by betulinic acid, i.e., an ED 50 value of about 2 μg/ml. However, none of the other cancer cell lines tested was affected by betulinic acid (i.e., ED 50 values of greater than 20 μg/ml). Such clearly defined cell-type specificity demonstrated by betulinic acid is both new and unexpected.
[0025] For example, as illustrated in Table 1, other known antitumor agents, such as paclitaxel, camptothecin, ellipticine, homoharringtonine, mithramycin A, podopyllotoxin, vinblastine and vincristine, demonstrated relatively intense, nonselective cytotoxic activity with no discernible cell-type selectivity. Moreover, the cytotoxic response mediated by betulinic acid is not exclusively limited to the MEL-2 melanoma cell line. Dose-response studies performed with additional human melanoma cell lines, designated MEL-1, MEL-3 and MEL-4, demonstrated ED 50 values of 1.1, 3.3 and 4.8 μg/ml, respectively.
[0026] In the following Table 1, the extracted betulinic acid and the other pure compounds were tested for cycotoxity against the following cultured human cell lines: A431 (squamous cells), BC-1 (breast), COL-2 (colon), HT-1080 (sarcoma), KB (human oral epidermoid carcinoma), LNCaP (prostate), LU-1 (lung), MEL-2 (melanoma), U373 (glioma) and ZR-75-1 (breast).
TABLE 1 Cytotoxic Activity Profile of the Crude Ethyl Acetate Extract Obtained from Ziziphus mauritiana , Betulinic acid, Other Antineoplastic Agents ED 50 (μg/ml) Compound A431 BC-1 COL-2 HT-1080 KB LNCaP LU-1 MEL-2 U373 ZR 75-1 Ziziphus mauritiana >20 >20 >20 9.5 >20 >20 5.2 3.7 >20 15.8 crude extract Betulinic acid >20 >20 >20 >20 >20 >20 >20 2.0 >20 >20 Taxol 0.00 0.02 0.02 0.00 0.02 0.02 0.00 0.06 0.008 0.02 Camptothecin 0.00 0.07 0.005 0.01 0.00 0.006 0.00 0.02 0.000 0.001 Ellipticine 0.5 0.2 0.3 1.8 0.04 0.8 0.02 0.9 1.6 0.9 Homoharringtonine 0.02 0.03 0.1 0.01 0.00 0.03 0.03 0.04 0.2 0.06 Mithramycin A 0.09 0.3 0.06 1.5 0.09 0.05 0.2 1.2 0.04 0.2 Podophyllotoxin 0.03 0.03 0.005 0.00 0.08 0.04 0.00 0.003 0.004 0.4 Vinbiastine 0.05 0.06 0.01 0.02 0.04 0.1 0.02 0.01 1.1 0.3 Vincristine 0.01 0.01 0.02 0.02 0.00 0.1 0.05 0.02 0.06 0.4
[0027] Betulinic acid (1) has the structural formula:
[0028] Betulinic acid is fairly widespread in the plant kingdom, and, as a compound frequently encountered, some previous biological activities have been reported.
[0029] Betulinic acid was obtained by extracting a sample of air-dried, milled stem bark (450 g) of Z. mauritiana with 80% aqueous methanol. The aqueous methanol extract then was partitioned successively with hexane and ethyl acetate to provide hexane, ethyl acetate and aqueous extracts. Among these extracts, the ethyl acetate (13.5 g) extract showed cytotoxic activity against a cultured melanoma cell line (MEL-2) with an ED 50 of 3.7 μg/ml. The ethyl acetate extract was chromatographed on a silica gel column using hexane-ethyl acetate (4:1 to 1:4) as eluent to give 10 fractions. Fractions 3 and 4 were combined and subjected to further fractionation to afford an active fraction (fraction 16) showing a major single spot by thin-layer chromatography [R f 0.67: CHCl 3 :MeOH (chloroform:methanol) (10:1)], which yielded 72 mg of colorless needles after repeated crystallization from methanol (overall yield from dried plant material: 0.016% w/w).
[0030] As confirmed by the data summarized in Table 1, betulinic acid has been reported as noncytotoxic with respect to cultured KB cells. Cytotoxicity of the crude extracts and purified compounds was determined in a number of cultured human cancer cell lines. Table 1 sets forth the various types of cancer cells evaluated. The cells were cultured in appropriate media and under standard conditions. To maintain logarithmic growth, the media were changed 24 hours prior to cytotoxic assays. On the day of the assay, the cells were harvested by trypsinization, counted, diluted in media, and added to 96-well plates containing test compounds dissolved in DMSO; the final DMSO concentration was 0.05%.
[0031] The plates were incubated for three days. Following the incubation period, the cells were fixed and stained with sulforhodamine B (SRB) dye. The bound dye was liberated with Tris base, and the OD 515 was measured on an ELISA reader. The growth of the betulinic acid-treated cells was determined by the OD 515 values, and the growth was compared to the OD 515 values of DMSO-treated control cells. Dose response studies were performed to generate ED 50 values.
[0032] The isolated active compound, betulinic acid (ED 50 of 2.0 μg/ml for MEL-2), has a molecular formula of C 30 H 48 O 3 , as determined by high-resolution mass spectral analysis, a melting point range of 292-293° C. (decomposition). The literature melting point range for betulinic acid is 290-293° C. A mixed melting point range with a known sample of betulinic acid was not depressed. The optical rotation of the compound was measured as +7.3° (c=1.2; pyridine) (lit. +7.5°). The identity of the isolated compound as betulinic acid was confirmed by comparing the above physical properties, as well as 1 H-nmr, 13 C-nmr and mass spectral data of the isolated compound, with physical data and spectra of a known sample of betulinic acid as reported in the literature.
[0033] To test the in vivo ability of betulinic acid to serve as an antineoplastic agent against malignant melanoma, a series of studies was performed with athymic (nude) mice injected subcutaneously with human melanoma cells (MEL-2). The initial study investigated the activity of betulinic acid against unestablished tumors. Treatment with betulinic acid began on day 1, i.e., 24 hours, following tumor cell injection. At doses of 50, 250, and 500 mg/kg (milligram per kilogram) body weight, betulinic acid demonstrated effective inhibition of tumor growth with p values of 0.001 for each dose versus a control (FIG. 1). These results indicate that betulinic acid can be used to prevent melanoma by topical application of melanoma. Such a discovery is important for individuals who are predisposed to melanoma due to hereditary or environmental factors.
[0034] In particular, the data plotted in FIG. 1 was derived from experiments wherein four week old athymic mice were injected subcutaneously in the right flank with 3.0×10 8 UISO MEL-2 cells. UISO MEL-2 is a cell line derived from metastatic melanoma from human pleural fluid. Drug treatment was initiated on the day following tumor cell injection and continued every fourth day for a total of six doses. Four control animals received 0.5 ml intraperitoneal (IP) of PVP control solution, while treated animals (4 per group) received 50, 250 or 500 mg/kg/dose IP betulinic acid/PVP in deionized H 2 O. Betulinic acid was coprecipitated with PVP to increase solubility and bioavailability. The mice were weighed, and the tumors measured with a micrometer every other day throughout the study. All animals were sacrificed and autopsied on day 33, when the mean tumor volume in the control animals was approximately one cm 3 .
[0035] There was greater inhibition of tumor growth at the highest dose of betulinic acid versus the lowest dose (p=0.04). Toxicity was not associated with the betulinic acid treatment because toxicity is indicated by loss of body weight or other forms of acute toxicity. No weight loss was observed.
[0036] Next, in vivo testing of betulinic acid was performed on established melanomas. In this study, treatment was withheld until day 13, by which time a palpable tumor mass was present in all mice. As illustrated in FIG. 2, under these conditions betulinic acid successfully abrogated tumor growth (p=0.0001). Furthermore, tumor growth did not parallel that of the control (untreated) group even 14 days after the termination of treatment.
[0037] In particular, with respect to FIG. 2, four-week-old athymic mice were injected with 5×10 8 MEL-2 cells subcutaneously in the right flank. Four treatment groups of five mice each were studied. In one group, the mice received 250 mg/kg/dose of IP betulinic acid/PVP every third day for six total doses initiated the day following tumor cell injection. The control group received 0.5 ml IP saline. A DTIC treatment group received 4 mg/kg/dose IP DTIC every third day from day 13 to day 28 of the study. The betulinic acid treatment group received 250 mg/kg/dose IP betulinic acid/PVP every third day from day 13 to day 27. The control and DTIC-treated mice were sacrificed and autopsied on day 36 due to their large tumor burden. The remaining mice were sacrificed and autopsied on day 41.
[0038] As illustrated in FIG. 2, the efficacy of betulinic acid also was compared to DTIC, which is clinically available for the treatment of metastatic melanoma. The dose of DTIC, which is limited by toxicity, was selected to be equivalent to that administered to human patients. Tumor growth in the betulinic acid-treated group was significantly less than that observed in the DTIC-treated animals (p=0.0001). Compared to controls, DTIC produced a significant, but less pronounced, reduction in tumor growth, with a p value of 0.01. A fourth group in this study was treated with a schedule similar to that in the initial study. Under these conditions, betulinic acid, as demonstrated before, significantly inhibited tumor development (p=0.0001) and caused a prolonged reduction in tumor growth of up to three weeks following treatment termination.
[0039] [0039]FIGS. 4 and 5 illustrate that betulinic acid also showed activity against MEL-1 cells. In particular, with respect to FIGS. 4 and 5, four week old athymic mice were injected subcutaneously in the right flank with 5.0×10 8 UISO MEL-1 cells. Drug treatment was initiated on the day following tumor cell injection and continued every fourth day for a total of six doses. Four control animals received 0.5 ml intraperitoneal (IP) saline, while treated animals (4 per group) received 5, 50 or 250 mg/kg/dose IP betulinic acid/PVP in dd H 2 O. The mice were weighed, and tumors were measured with a micrometer every third day throughout the study. Treated animals were sacrificed and autopsied on day 41, when the mean tumor volume in the control mice was approximately 0.5 cm 3 . The control mice then received six doses of 50 mg/kg every fourth day beginning day 41 and were sacrificed and autopsied on day 71.
[0040] The results illustrated in FIGS. 4 and 5 with respect to MEL-1 cells were similar to the results illustrated in FIGS. 1 and 2. Betulinic acid therefore is active both against MEL-1 and MEL-2 cells.
[0041] The mechanism by which antitumor agents mediated their activity is of great theoretical and clinical importance. Therefore, the mode of action by which betulinic acid mediates the melanoma-specific effect was investigated. Visual inspection of melanoma cells treated with betulinic acid revealed numerous surface blebs. This observation, as opposed to cellular membrane collapse, suggested the induction of apoptosis. One of the most common molecular and cellular anatomical markers of apoptosis is the formation of “DNA ladders,” which correspond to the products of random endonucleolytic digestion of internucleosomal DNA. Although recent studies have shown that a lack of DNA laddering does not necessarily indicate a failure to undergo apoptosis, double-strand DNA scission that yields a fragment of about 50 kilobase pairs (Kbp) has been shown to consistently correlate with induction of apoptosis by various treatments in a variety of cell lines. Thus, generation of the 50 Kbp fragment is a reliable and general indicator of apoptosis. Generation of the fragment occurs upstream of the process leading to DNA ladders and represents a key early step in the commitment to apoptosis.
[0042] Therefore, an important feature of the present invention is a method of analyzing and quantifying the formation of the 50 Kbp fragment as a biomarker for induction of apoptosis in human cancer cell lines. This method comprises treatment of cells in culture, followed by analysis of the total cellular DNA content using agarose field-inversion gel electrophoresis. Under these conditions, the 50 Kbp fragment is resolved as a diffuse band. The fraction of the total cellular DNA represented by the 50 Kbp fragment is determined by densitometry on the contour of this band.
[0043] To investigate the ability of betulinic acid to induce apoptosis, the above-described method was adapted for use with the MEL-2 cell line. As shown in FIG. 3A, time-dependent formation of a 50 Kbp DNA fragment was induced by betulinic acid with MEL-2 cells. Induction was at a maximum after a 56 hour treatment period. After this time period, a decline in the relative amount of the 50 Kbp fragment was observed, probably due to internal degradation. Also observed in the agarose gel were DNA fragments of about 146 and about 194 Kbp, which are theorized to be precursors in the process leading to the formation of the 50 Kbp fragment. Additionally, the induction of apoptosis (50 Kbp fragment) mediated by betulinic acid was dose-dependent (FIG. 3B), and the ED 50 value (about 1.5 μg/ml) observed in the apoptotic response closely approximated the ED 50 value previously determined for the cytotoxic response (Table 1).
[0044] With further respect to FIG. 3A, cultured MEL-2 cells (10 6 cells inoculated per 25 cm 2 flask) were treated with 2 g/ml betulinic acid (200 μg/ml DMSO, diluted 1:100 in media) for 24, 32, 48, 56 and 72 hours. After the treatment, the cells were harvested, collected by centrifugation, then snap frozen in liquid nitrogen for subsequent analysis. Samples were analyzed on a 1% agarose gel in a Hoefer HE100 SuperSub apparatus cooled to 10° C. by a circulating water bath. The electrode buffer was 0.5×TBE buffer containing 0.25 μg/ml ethidium bromide and was circulated during electrophoresis. Each gel included 20 μL Sigma Pulse Marker 0.1-200 Kbp DNA size markers. Prior to sample loading, 50 μL 2% SDS was added to each sample well. Each sample tube was rapidly thawed, then the pelleted cells were immediately transferred in a volume about 50 μL to the well containing SDS. Each well then was overlaid with molten LMP agarose, which was allowed to gel prior to placing the gel tray in the SuperSub apparatus.
[0045] Electrophoresis was performed at 172 volts for a total of 18 hours using two sequential field inversion programs with pulse ramping. The DNA/ethidium bromide fluorescence was excited on a UV transilluminator and photographed using Polaroid type 55 P/N film. The negative was analyzed using a PDI scanning densitometer and Quantity One software. The intensity of the 50 Kbp fragment was determined by measuring the contour optical density (OD×mm 2 ) as a percent of the total optical density in the sample lane, including the sample well. The decrease in the 50 Kbp band definition caused by internal degradation, and does not represent a reversal of the process.
[0046] With further respect to FIG. 3B, cultured MEL-2 cells were treated for 56 hours with the following concentrations of betulinic acid: 0, 0.1, 1.0, 2.0, 4.0 and 8.0 μg/ml. The cells were harvested and apoptosis measured as described for FIG. 3A. The experiment was repeated and a similar dose-response curve was observed (data not shown).
[0047] These data suggest a causal relationship, and it is theorized that betulinic acid-mediated apoptosis is responsible for the antitumor effect observed with athymic mice. Time-course experiments with human lymphocytes treated in the same manner with betulinic acid at concentrations of 2 and 20 μg/ml did not demonstrate formation of the 50 Kbp fragment (data not shown) indicating the specificity and possible safety of the test compound.
[0048] Taking into account a unique in vitro cytotoxicity profile, a significant in vivo activity, and mode of action, betulinic acid is an exceptionally attractive compound for treating human melanoma. Betulinic acid also is relatively innocuous toxicity-wise, as evidenced by repeatedly administering 500 mg/kg doses of betulinic acid without causing acute signs of toxicity or a decrease in body weight. Betulinic acid was previously found to be inactive in a Hippocratic screen at 200 and 400 mg/kg doses.
[0049] Betulinic acid also does not suffer from the drawback of scarcity. Betulinic acid is a common triterpene available from many species throughout the plant kingdom. More importantly, a betulinic acid analog, betulin, is the major constituent of white-barked birch species (up to 22% yield), and betulin can be converted to betulinic acid.
[0050] In addition to betulinic acid, betulinic acid derivatives can be used in a topically applied composition to selectively treat, or prevent or inhibit, a melanoma. Betulinic acid derivatives include, but are not limited to esters of betulinic acid, such as betulinic acid esterified with an alcohol having one to sixteen, and preferably one to six, carbon atoms, or amides of betulinic acid, such as betulinic acid reacted with ammonia or a primary or secondary amine having alkyl groups containing one to ten, and preferably one to six, carbon atoms.
[0051] Another betulinic acid derivative is a salt of betulinic acid. Exemplary, but nonlimiting, betulinic acid salts include an alkali metal salt, like a sodium or potassium salt; an alkaline earth metal salt, like a calcium or magnesium salt; an ammonium or alkylammonium salt, wherein the alkylammonium cation has one to three alkyl groups and each alkyl group independently has one to four carbon atoms; or transition metal salt.
[0052] Other betulinic acid derivatives also can be used in the composition and method of the present invention. One other derivative is the aldehyde corresponding to betulinic acid or betulin. Another derivative is acetylated betulinic acid, wherein an acetyl group is positioned at the hydroxyl group of betulinic acid.
[0053] In particular, betulinic acid derivatives have been synthesized and evaluated biologically to illustrate that betulinic acid derivatives possess selective antitumor activity against human melanoma cells lines in vitro. It has been demonstrated that modifying the parent structure of betulinic acid provides numerous betulinic acid derivatives that can be deused to prevent or inhibit malignant tumor growth, especially with respect to human melanoma. The antitumor activity of betulinic acid derivatives is important because betulinic acid, although exhibiting a highly selective activity against melanomas, also possesses a low water solubility. The low water solubility of betulinic acid, however, can be overcome by providing an appropriate derivative of betulinic acid. Modifying the parent structure betulinic acid structure also can further improve antitumor activity against human melanoma.
[0054] An examination of the structure of betulinic acid, i.e., compound (1), reveals that betulinic acid contains three positions, i.e., the C-3, C-20, and C-28 positions, where functional groups can be introduced. In addition, the introduced functional groups, if desired, then can be modified. Through a series of reactions at these three positions, a large number of betulinic acid derivatives were prepared and evaluated for bioefficacy against a series of human tumor cell lines, especially against human melanoma cell lines.
[0055] With respect to modifications at the C-3 position of betulinic acid, the hydroxyl group at the C-3 position can be converted to a carbonyl group by an oxidation reaction. The resulting compound is betulonic acid, i.e., compound (2). The ketone functionality of betulonic acid can be converted to oxime (3) by standard synthetic procedures. Furthermore, a large number of derivatives (4) can be prepared through substitution reactions performed on the hydroxyl group of oxime (3), with electrophiles, as set forth in equation (a):
[0056] wherein R a ═H or C 1 -C 16 alkyl, or R a ═COC 6 H 4 X, wherein X═H, F, Cl, Br, I, NO 2 , CH 3 , or OCH 3 , or R a ═COCH 2 Y, wherein Y═H, F, Cl, Br, or I, or R a ═CH 2 CHCH 2 or CH 2 CCR 1 , wherein R 1 is H or C 1 -C 6 alkyl. When R a is C 1 -C 16 alkyl, preferred alkyl groups are C 1 -C 6 alkyl groups.
[0057] The ketone functionality of betulonic acid can undergo a reductive amination reaction with various aliphatic and aromatic amines in the presence of sodium cyanoborohydride (NaBH 3 CN) to provide the corresponding substituted amines (5) at the C-3 position, as set forth in equation (b).
[0058] wherein R b ═H or C 1 -C 10 alkyl, or R b ═C 6 H 4 X. A primary amine derivative, i.e., R b ═H, at the C-3 position can be reacted with a series of acyl chlorides or anhydrides, or alkyl halides, to provide amides and secondary amines (6), respectively, as set forth in equation (c).
[0059] wherein R c ═COC 6 H 4 X, or R c ═COCH 2 Y, or R c ═CH 2 CHCH 2 or CH 2 CCR 1 .
[0060] The ketone functionality of betulonic acid can react with a series of lithium acetylides (i.e., LiC≡CR 1 ) to provide alkynyl alcohol derivatives (7) at the C-3 position. Based on the chemical reactivity and the stereoselectivity of the betulonic acid structure, α-alkynyl substituted β-hydroxyl alkynyl betulinic acid are the major products of the reaction, as set forth in equation (d).
[0061] wherein R d ═CCR 1 , wherein R 1 is H or C 1 -C 6 alkyl.
[0062] A number of esters also can be prepared by reacting the hydroxyl group of betulinic acid with a variety of acyl chlorides or anhydrides (8), as set forth in equation (e).
[0063] wherein R e ═R 1 CO or XC 6 H 4 CO.
[0064] With respect to modification at the C-28 position, the carboxyl group of betulinic acid can be converted to a number of esters (9) and amides (10) by reaction with an alcohol or an amine, respectively, as set forth in equations (f) and (g). Depending on the types of functional groups present on the alcohols or amines, additional structural modification are possible. The carboxyl group also can be converted to a salt, in particular an alkali metal salt, an alkaline earth salt, an ammonium salt, an alkylammonium salt, a hydroxyalkyl ammonium salt, or a transition metal salt.
[0065] wherein R f ═C 1 -C 10 alkyl, phenyl, substituted phenyl (C 6 H 4 X), or CH 2 CCR 1 .
[0066] The activated C-28 hydroxyl group of betulin can undergo substitution reactions, like SN-2 type reactions, with nucleophiles to provide an amino (11) or an ether derivative (12), as set forth in equations (h) and (i).
[0067] wherein R g ═H or C 1 -C 16 alkyl, or R g ═C 6 H 4 X, and wherein R h ═C 1 -C 16 alkyl or C 6 H 4 X.
[0068] The hydroxyl group at the C-28 position can be oxidized to yield an aldehyde, which in turn can react with hydroxylamine to provide a hydroxyloxime compound. The hydroxyloxime can react with a variety of electrophiles to provide the oxime derivatives (13), as set forth in equation (j).
[0069] wherein R i ═H or C 1 -C 16 alkyl, or R i ═COC 6 H 4 X, or R i ═COCH 2 Y, or R i ═CH 2 CHCH 2 or CH 2 CCR 1 .
[0070] The aldehyde at the C-28 position also can react with a series of lithium acetylide compounds to yield a variety of alkynyl betulin derivative (14), as set forth in equation (k).
[0071] wherein R j ═CCR 1 , wherein R 1 ═H or C 1 -C 6 alkyl.
[0072] With respect to modifications at the C-20 position, the isoprenyl group at the C-20 position can be ozonized to yield a ketone (15) at C-20 position, as set forth in equation (1). A variety of reactions performed on the ketone functionality can provide a series of different derivatives. For example, the ketone functionality of compound (15) can be easily converted to a variety of oximes. Furthermore, a number of additional oxime derivatives (16) can be prepared through substitution reactions at the hydroxyl group of the hydroxyloxime with electrophiles, as set forth in equation (m).
[0073] wherein R k ═H or C 1 -C 16 alkyl, or R k ═COC 6 H 4 X or R k ═COCH 2 Y, or R k ═CH 2 CHCH 2 or CH 2 CCR 1 .
[0074] The ketone functionality also can undergo a reductive amination reaction with a series of aliphatic and aromatic amines in the presence of NaBH 3 CN to provide a corresponding substituted amine (17) at the C-20 position, as set forth in equation (n).
[0075] wherein R 1 ═C 1 -C 16 alkyl, or R 1 ═C 6 H 4 X, or R 1 ═COC 6 H 4 X, or R 1 ═COCH 2 Y, or R 1 ═CH 2 CHCH 2 or CH 2 CCR 1 .
[0076] The ketone can be reacted with a series of lithium acetylides to provide alkynyl alcohol derivatives (18) at the C-20 position, as set forth in equation (o).
[0077] wherein, R m ═CCR 1 .
[0078] The ketone further can be reduced to a secondary alcohol (19) to react with an acyl chloride to provide a series of esters (20) at the C-20 position, as set forth in equation (p).
[0079] wherein R n ═H, C 1 -C 16 alkyl, CH 2 CCR 1 , or R n ═CH 3 CO or XC 6 H 4 CO.
[0080] In addition, a number of different derivatives can be prepared through a combinatorial chemical approach. For example, as set forth below, in the preparation of oximes at the C-20 position, a number of electrophiles, e.g., a variety of alkyl halides, can be added together in one reaction vessel containing the hydroxyloxime to provide a mixture of betulinic acid derivatives. Each reaction product in the mixture can be isolated by using semi-preparative HPLC processes using appropriate separation conditions, then submitted for bioassay.
[0081] wherein P is a protecting group for the secondary alcohol functionality.
[0082] A low temperature reaction of betulonic acid with a mixture of lithium acetylides in a single reaction vessel, as set forth below, yielded a mixture of alkynyl alcohols at the C-3 position. Each component in the mixture can be isolated by using semi-preparative HPLC processes using appropriate separation conditions, then submitted for bioassay.
[0083] In order to demonstrate that betulinic acid derivatives have a potent bioefficacy, various derivatives were subjected to a series of biological evaluation tests. The biological evaluation of the derivatives focused on the activity against human melanoma cell lines. In particular, the following betulinic acid derivatives were prepared and tested for cytotoxicity profile against human melanoma cell lines and against a number of selected nonmelanoma cell lines. The results are summarized in Table 2. The data shows that some hydrogenated derivatives, i.e., compounds 5 and 11, are less active than nonhydrogenated derivatives 13 and 10, respectively. However, other hydrogenated derivatives, i.e., compounds 7 and 6, showed a comparable biological activity to nonhydrogenated derivatives 2 and 8, respectively. Therefore, it is possible to optimize the modification at the C-20 position to yield more potent betulinic acid derivatives. Table 3 contains a summary of data showing the effect of hydrogenation at the C-20 position.
TABLE 2 Cytotoxicity Data of Betulinic Acid Derivatives ED 50 [μg/mL] (Std. Dev.) MALE- Compound R 1 R 2 R 3 MEL-2 MEL-6 MEL-8 3M LOX KB 1 O═ CHO CH 2 ═C(CH 3 ) 2 7.4 (2.4) >20 3.2 (1.2) >20 18.5 12.9 2 HO—N═ COOH CH 2 ═C(CH 3 ) 2 2.4 (0.3) 14.8 (2.0) 1.9 (1.0) 15.8 9.1 >20 3 CH 3 O—N═ CHNOCH 3 CH 2 ═C(CH 3 ) 2 >20 >20 >20 >20 >20 20 4 HO—N═ CHNOH CH 2 ═C(CH 3 ) 2 2.2 (0.7) 11.9 (2.7) 1.4 (0.6) 17.5 4.1 3.3 5 CH 3 O—N═ COOH C(CH 3 ) 3 >20 >20 >20 >20 6 O═ COOH C(CH 3 ) 3 0.7 (0.6) 10.8 (2.6) 0.9 (0.4) 20 (Dihydrobetulonic acid) 7 HO—N═ COOH C(CH 3 ) 3 2.2 (0.3) 13.1 (1.1) 1.6 (1.1) 13.9 8 O═ COOH CH 2 ═C(CH 3 ) 2 0.9 (0.8) 15.3 (3.4) 0.4 (0.1) 20 6.9 2.5 (Betulonic acid) 9 H 2 N— COOH CH 2 ═C(CH 3 ) 2 1.3 (0.4) 5.2 (2.6) 1.3 (0.5) 3.1 10 HO— COOH CH 2 ═C(CH 3 ) 2 1.2 (0.1) 13.2 (1.5) 1.0 (0.3) 17.6 (0.5) >20 >20 (Betulinic acid) 11 HO— COOH C(CH 3 ) 3 5.8 >20 >20 (Dihydrobetulinic acid) 12 HO— CH 2 OH CH 2 ═C(CH 3 ) 2 >20 >20 >20 (Betulin) 13 CH 3 O—N═ COOH CH 2 ═C(CH 3 ) 2 8.3 >20 4.3 14 HO— COOCH 3 CH 2 ═C(CH 3 ) 2 8.3 12.5 11.8 (Methyl betulinate) 15 HO— CH 3 CH 2 ═C(CH 3 ) 2 17.6 15.6 >20 (Lupeol) 16 C 6 H 4 COO— CH 3 CH 2 ═C(CH 3 ) 2 >20 >20 >20 (Lupeol benzoate)
[0084] [0084] TABLE 3 Cytotoxicity Data of Betulinic Acid Derivatives (Effect of Hydrogenation at C-20) ED 50 [μg/mL] (Std. Dev.) MALE- Compound R 1 R 2 R 3 MEL-2 MEL-6 MEL-8 3M LOX KB 13 CH 3 O—N═ COOH CH 2 ═C(CH 3 ) 2 8.3 >20 4.3 5 CH 3 O—N═ COOH C(CH 3 ) 3 >20 >20 >20 >20 10 HO— COOH CH 2 ═C(CH 3 ) 2 1.2 (0.1) 13.2 (1.5) 1.0 (0.3) 17.6 (0.5) >20 >20 (Betulinic acid) 11 HO— COOH C(CH 3 ) 3 5.8 >20 >20 (Dihydrobetulinic acid) 2 HO—N═ COOH CH 2 ═C(CH 3 ) 2 2.4 (0.3) 14.8 (2.0) 1.9 (1.0) 15.8 9.1 >20 7 HO—N═ COOH C(CH 3 ) 3 2.2 (0.3) 13.1 (1.1) 1.6 (1.1) 13.9 8 O═ COOH CH 2 ═C(CH 3 ) 2 0.9 (0.8) 15.3 (3.4) 0.4 (0.1) 20 6.9 2.5 (Betulonic acid) 6 O═ COOH C(CH 3 ) 3 0.7 (0.6) 10.8 (2.6) 0.9 (0.4) 20 (Dihydrobetulonic acid)
[0085] The modification of betulinic acid at the C-3 position showed that all compounds, except methoxy oxime 13, expressed a comparable biological activity toward melanoma cell lines (Table 4). Amino compound 9 exhibited an improved cytotoxicity compared to betulinic acid 10. Compounds. 2, 8, and 13 showed a decrease in selective cytotoxicity compared to betulinic acid.
TABLE 4 Cytotoxicity Data of Betulinic Acid Derivatives (Modification at C-3 Position) ED 50 [μg/mL] (Std. Dev.) Compound R 1 R 2 R 3 MEL-2 MEL-6 MEL-8 MALE-3M LOX KB 10 HO— COOH CH 2 ═C(CH 3 ) 2 1.2 (0.1) 13.2 (1.5) 1.0 (0.3) 17.6 (0.5) >20 >20 (Betulinic acid) 8 O═ COOH CH 2 ═C(CH 3 ) 2 0.9 (0.8) 15.3 (3.4) 0.4 (0.1) 20 6.9 2.5 (Betulonic acid) 2 HO—N═ COOH CH 2 ═C(CH 3 ) 2 2.4 (0.3) 14.8 (2.0) 1.9 (1.0) 15.8 9.1 >20 13 CH 3 O—N═ COOH CH 2 ═C(CH 3 ) 2 8.3 >20 4.3 9 H 2 N— COOH CH 2 ═C(CH 3 ) 2 1.3 (0.4) 5.2 (2.6) 1.3 (0.5) 3.1
[0086] With respect to modifications at the C-28 position, the free carboxylic acid group at C-28 position is important with respect to expression of biological activity (Table 5). However, it is unknown whether the size or the strength of hydrogen bonding or the nucleophilicity of the C-28 substituents is responsible for the biological effect.
TABLE 5 Cytotoxicity Data of Betulinic Acid Derivatives (Modification at C-28 Position) ED 50 [μg/mL] (Std. Dev.) Compound R 1 R 2 R 3 MEL-2 MEL-6 MEL-8 MALE-3M LOX KB 12 HO— CH 2 OH CH 2 ═C(CH 3 ) 2 >20 >20 >20 (Betulin) 10 HO— COOH CH 2 ═C(CH 3 ) 2 1.2 (0.1) 13.2 (1.5) 1.0 (0.3) 17.6 (0.5) >20 >20 (Betulinic acid) 14 HO— COOCH 3 CH 2 ═C(CH 3 ) 2 8.3 12.5 11.8 (Methyl betulinate) 15 HO— CH 3 CH 2 ═C(CH 3 ) 2 17.6 15.6 >20 (Lupeol)
[0087] The biological activity changes attributed to oximes is illustrated in Table 6. The hydroxyloxime 4 improved the cytotoxicity profile, although selectivity was lost. It appears that the size of the substituent and its ability to hydrogen bond may influence the expression of the biological activity.
TABLE 6 Cytotoxicity Data of Betulinic Acid Derivatives (Effect by Oximes) ED 50 [μg/mL] (Std. Dev.) Compound R 1 R 2 R 3 MEL-2 MEL-6 MEL-8 MALE-3M LOX KB 12 HO— CH 2 OH CH 2 ═C(CH 3 ) 2 >20 >20 >20 (Betulin) 1 O═ CHO CH 2 ═C(CH 3 ) 2 7.4 (2.4) >20 3.2 (1.2) >20 18.5 12.9 4 HO—N═ CHNOH CH 2 ═C(CH 3 ) 2 2.2 (0.7) 11.9 (2.7) 1.4 (0.6) 17.5 4.1 3.3 3 CH 3 O—N═ CHNOCH 3 CH 2 ═C(CH 3 ) 2 >20 >20 >20 >20 >20 20
[0088] The above tests show that modifying the parent structure of betulinic acid can provide derivatives which can be used as potent antitumor drugs against melanoma. Betulinic acid derivatives having a comparable or better antitumor activity than betulinic acid against human melanoma have been prepared. In addition, even though betulinic acid has a remarkably selective antitumor activity, betulinic acid also has a poor solubility in water. The low solubility of betulinic acid in water can be overcome by introducing an appropriate substituent on the parent structure, which in turn can further improve selective antitumor activity. In addition, because the parent compound, betulinic acid, has shown to possess anti-HIV activity, the derivatives also can be developed as potential anti-HIV drug candidates.
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A composition and method of preventing or inhibiting tumor growth, and of treating malignant melanoma, without toxic side effects are disclosed. Betulinic acid or a betulinic acid derivative is the active compound of the composition, which is topically applied to the situs of tumor.
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BACKGROUND OF THE INVENTION
The present invention relates generally to boat railings and, more particularly, to an improved connector internally threaded into each stanchion and into an insert within the generally horizontal rail for providing adjustable movement for the base of each stanchion before being connected to the surface of the boat.
Although alternative means for connecting boat railings and stanchions have been disclosed, such as seen in U.S. Pat. No. 3,055,024, granted on Sept. 25, 1962, to Gerbase G. Schmitt; and U.S. Pat. No. 3,193,228, granted on July 6, 1965; and U.S. Pat. No. 3,429,558, granted on Feb. 25, 1969, boat railings are typically generally unitary welded structures manufactured at a location remote from the manufacture of the boat and installed on the boat surface after manufacture is complete. Since the stanchions are typically disposed at an acute angle to the generally horizontal railing and are fixed relative thereto, such as by welding, the base of each stanchion must be positioned to match the corresponding surface of the boat before being fixed or welded to the rail. As a result, any variations in the manufacturing of the slope of the surface of the boat to which the base of the stanchion is to be attached results in an inexact fit between the base and the boat when the railing is installed.
Furthermore, an entire railing is generally fabricated for each particular boat on a custom basis, with the bases of the stanchions prefixed to match the particular boat to which it is to be installed. Accordingly, shipping and storage of such structures becomes a cumbersome and space consuming task. It would be desirable to provide a boat railing that would be capable of greater flexibility in use, require less storage space and create less problems in shipping from one location to another.
Asthetically, it is preferable that the boat railing have a clean, sleek look that can be provided by the welding process. This unitary look cannot be provided with railing connectors such as seen in the aforementioned U.S. Pat. No. 3,055,024. Accordingly, it would be desirable to provide a boat railing that would permit adjustment of the position of the base of the stanchions before being fixed to the boat surface, in addition to solving the above-noted problems, while having a clean, unitary look and being able to be securely and tightly fastened to the boat.
SUMMARY OF THE INVENTION
It is an object of this invention to overcome the aforementioned disadvantages of the prior art by providing an internally threaded boat railing connector for connecting each stanchion to the rail to permit adjustable movement of the base of the stanchion before being connected to the boat.
It is another object of the invention to provide an easily usable method of assembling a boat railing on a boat.
It is another object of this invention to provide two axes of adjustable movement for the base of a stanchion of a boat railing prior to connection thereof to a boat.
It is still another object of this invention to facilitate the manufacture of a boat railing and the installation thereof to the surface of a boat.
It is yet another object of this invention to reduce shipping problems of the boat railing from the manufacture thereof to the location of installation.
It is still another object of this invention to provide a means for connecting the stanchion to the rail to provide a solid boat railing without welding.
It is a further object of this invention to provide a means for locking the internal connector to prevent the stanchion from becoming loosened from the rail to which it is connected.
It is a feature of this invention that a boat railing has a unitary appearance without welding the stanchions to the generally horizontal rail.
It is an advantage of this invention that shipping and storage problems for boat railings are significantly reduced.
It is yet a further object of this invention to provide a boat railing that requires less storage space than a unitary welded boat railing.
It is still a further object of this invention to provide a boat railing with a greater flexibility in use.
It is still a further object of this invention to provide a non-welded boat railing which is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, asthetically pleasing in appearance, and simple and effective in use.
It is another advantage of this invention that the individual stanchions on a boat railing can be quickly and easily replaced without removing the entire railing from the boat.
It is another feature of this invention that the railing can be partially disassembled to facilitate the shipments of boats by the boat manufacturer.
These and other objects, features and advantages are accomplished according to the instant invention by providing a boat railing wherein the stanchions are connected to the rail by a threaded member internally threaded into both the rail and each respective stanchion. An insert adapted for connection to the threaded member can be movably inserted within the rail to provide adjustable movement about the axis of the rail. A combination of the rotative movements of each stanchion on the threaded member and about the axis of the rail enables the bases of the stanchion to be properly fitted to the surface of the boat irrespective of the slope of the surface to which the base is to be attached.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a side elevational view of a boat having a railing incorporating the principles of the instant invention affixed thereto;
FIG. 2 is an enlarged cross-sectional view of the connector fastening the stanchion to the generally horizontal rail, corresponding to the circled insert seen in FIG. 1, the connector being shown in a loosened state to permit adjustment of the base of the stanchion;
FIG. 3 is an enlarged cross-sectional view corresponding to FIG. 2 with the connector being tightened to fixedly secure the stanchion to the rail;
FIG. 4 is a cross-sectional view of an alternative embodiment of the railing connector in its tightened position corresponding to the view seen in FIG. 3;
FIG. 5 is a cross-sectional view of another alternative embodiment of the railing connector shown in its tightened position corresponding to the view seen in FIG. 3;
FIG. 6 is a cross-sectional view of the railing connector taken along lines 6--6, showing the extent of adjustable movement in phantom;
FIG. 7 is a cross-sectional view taken along lines 7--7 in FIG. 4 through the driver portion of the railing connector; and
FIG. 8 is a cross-sectional view taken through the driver portion of the railing connector seen in FIG. 5, taken along lines 8--8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and, particularly, to FIG. 1, a side elevational view of a boat having a railing incorporating the principles of the instant invention affixed thereto can be seen. The boat 10 is shown in a respresentative form in a side elevational view with a representative railing 15 affixed to the top surface 12 of the boat 10. Although the surface 12 of the boat 10 to which the 15 is connected is shown as being generally horizontal, it should be noted that typically the surface 12 will have a pitch thereto for various reasons, including draining water to the outer edges of the boat 10. The railing 15 is comprised of vertically inclined stanchions 16 connected to a generally horizontal rail 18 at one end and via a base 17 to the top surface 12 of the boat 10 at the other end.
Referring now to FIGS. 1, 2 and 3, the details of the railing connector 20, connecting each stanchion 16 to the generally horizontal rail 18 can be seen. At the location of connection to each respective stanchion 16, the tubular rail 18 is provided with a movable insert 22. For the purposes of the instant invention, it is only necessary that the insert 22 be rotatably movable about the axis of the rail 18; however, the insert 22 may also be movable along the axis within the rail 18. The insert 22 is provided with a threaded opening 23 positioned therein for alignment with the angled stanchion 16. As will be described in further detail below, the threaded member 25 is engageable with the insert 22 through an oversized opening 19 in the underside of the rail 18, further reference thereto may be had to FIG. 6.
The upper end 25 of each stanchion 16 is provided with a plug 27 formed therein or affixed thereto as by welding to form a solid end piece in the tubular stanchion 16. The plug 27 is provided with a threaded hole 28 into which the railing connector 20 can be engaged. The threaded member 30 interconnects the upper end 25 of the stanchion 16 and the insert 22 positioned within the rail 18. The threaded member 30 includes a first threaded portion threadably engageable with the opening 23 in the rail insert 22 and a second threaded portion threadably engageable with the hole 28 in the plug 27 at the upper end 25 of the stanchion 16. Located between the first and second threaded portions 31,32, as seen in FIG. 7, is a hexagonal drive portion 34. As described below, the railing connector 20 is assembled such that a drive member 35 is engageable with the drive portion 34 to affect rotation of the threaded member 30.
As can be seen in FIGS. 2 and 3, the first and second threaded portions 31,32 have different pitched threads, although they are both threaded in the same direction. A sleeve or spacer 36, coped to fit the rail 18, extends between the drive member 35 and the rail 18 to provide an asthetically smooth and unitary appearance. The railing connector 20 also includes washers 37,38 disposed between the sleeve 36 in the drive member 35 and the drive member 35 and the stanchion 16, respectively. The drive member 35 is provided with flats 39 for cooperation with an external tool, such as a wrench, to effect rotation of the drive member 35, as best seen in FIG. 7.
To assemble a boat railing according to the principles of the instant invention, the first portion 31 of the threaded member 30 is inserted through the opening 19 in the bottom of the rail 18 and threaded into the threaded opening 23 in the rail insert 22 until, preferably, it is entirely received therewithin. After slipping the sleeve 36, washer 37, drive member 35 and washer 38 over the threaded member 30 in their respective positions shown in FIGS. 2 and 3, the stanchion 16 is threaded onto the second portion 32 of the threaded member 30 by engaging the second threaded portion 32 into the threaded hole 28 in the plug 27. By stopping the stanchion 16 within approximately one revolution of being snuggly secured against the washer 38 and drive member 35, adjustment of the position of the base 17 of the stanchion 16 can be accomplished by a combination of rotating the stanchion 16 on the second portion 32 of the threaded member 30 and rotating the stanchion 16 about the axis of the rail 18, within the limits imposed by the oversized hole 19, by rotating the sleeve 36 within the rail 18. After the position of the base 17 has been aligned with the surface 12 of the boat 10 to which it is to be fastened, the base 17 is secured to the boat 10 by fastening means (not shown). Through the use of an external tool, such as a wrench, engaged with the flats 39, the drive member 35 can be rotated, turning the drive portion 34 of the threaded member 30 to draw the rail 18 tightly down against the stanchion 16 until it is secured in place.
Even though both the first and second portions 31,32 of the threaded member 30 have threads extending in the same direction, the difference in thread spacing (pitch) permits the rail 18 to be drawn down against the stanchion. Because the pitch is greater on the second portion 32 than on the first portion 31, the threaded member 30 is drawn into the stanchion 16 faster than it is pulling out of the insert 22, resulting in a net shortening of the distance between the rail 18 and stanchion 16 until it is tight. Furthermore, the differences in the pitch of the threads on the first and second portions 31,32 operatively acts as a locking means through a wedging affect to prevent the railing connector 20 from loosening after being tightly drawn into position. The provision of washers 37,38 having a thickness at least as great as the thread pitch on the second portion 32 prevents the sleeve 36, drive member 35 and stanchion 16 from binding on each other, permitting the rail 18 to tighly drawn down toward the stanchion 16. As noted above, FIG. 2 indicates the preferred relative position of the various components of the railing connector 20 before the railing connector is tightened, while FIG. 3 depicts the relative positions of the components after the rail 18 has been tightly drawn down against the stanchion 16.
Referring to the alternative embodiment seen in FIG. 4, it can be seen that the threaded member 30 can be modified to include the first threaded portion 31, a drive portion 34 and a retaining portion 42 necked down to a diameter smaller than that of the drive portion 34 so as to pass through the hole 44 at the end of the stanchion 16. A head 45 formed as part of the retaining portion 42, or permanently affixed thereto as by welding, prevents the retaining portion 42 from being withdrawn from inside the stanchion 16. A lock washer 47 provides a means for locking the position of the threaded member 30 relative to the stanchion 16 after being tightened, while a small thrust washer 48 facilitates the tightening of the railing connector 20.
Obviously, the threaded member 20 must be preassembled within the end 43 of the stanchion 16 at the location of manufacturing of the railing 15 prior to securing the plug 27 to the stanchion end 45. However, the operation for assembly of the boat railing 15 is substantially the same as that described above relative to FIGS. 2 and 3. The washer 38, drive member 35, washer 37 and sleeve 36 must be slipped over the first portion 31 of the threaded member 30 before engaging the first portion 31 into the threaded opening 23 in the rail insert 22. After adjusting the base 17 for proper alignment with the top surface 12 of the boat 10, and fastening it thereto, the drive member 35 can be rotated with the assistance of a wrench or similar tool engaged with the flats 39 to draw the rail 18 downwardly against the stanchion 16, compressing the lock washer 47 until the railing connector 20 is tightly drawn up.
Referring now to the other alternative embodiment seen in FIGS. 5 and 8, it can be seen that the threaded member 30, with proper modifications, can be constructed from readily available hardware, such as a bolt 50 having the shaft 51 thereof passing through the hole 54 in the end of the stanchion 16 The threaded portion 31 is engaged into the threaded opening 23 of the rail insert 22. Instead of manufacturing the threaded member 30 from hexagonal shaped stock to provide a suitable drive portion 34, a passageway 56 can be drilled into the shaft 51 of the bolt 50 to receive a roll pin 57 positioned to project outwardly from the shaft 51. A keyway 59 cut into the drive member 35 permits the drive member 35 to slide down over the roll pin 57 for engagement therewith to cause rotation of the bolt 50.
Preferably, the bolt 50 is preassembled at the point of manufacture of the rail 15 with the roll pin 57 securely positioned to keep the bolt 50 from dropping down within the tubular stanchion 16. Assembly would be very similar to the embodiment depicted in FIG. 4, with the washer 38, drive member 35, washer 37 and sleeve 36 being slid over the threaded portion 31 of the bolt 50 prior to insertion thereof into the rail insert 22. Rotation of the drive member 35 in cooperation with engagement with the roll pin 57 draws the rail 18 downwardly toward the stanchions 16, compressing the lock washer 47.
One skilled in the art will readily realize the advantages of the instant invention. Since the rail and stanchions do not have to be preassembled and welded into a fixed location prior to shipping, shipping problems and space requirements are greatly reduced. Proper fit between the base 17 of the stanchion 16 can be obtained by adjustment of the stanchion 16 relative to the rail 18 prior to fixing the base 17 to the top surface 12 of the boat 10. It has been found that once tightly drawn into place, the boat railing 15 will support adequate weight and gives an asthetically pleasing appearance. Although it is preferable to construct the instant invention from stainless steel to minimize corrosion problems, since boats are often in contact with salt water, the instant invention is not so limited. It will also be realized that the stanchions can be individually replaced with relative ease, which cannot be accomplished with welded unitary railings.
It will be understood that changes in the details, materials, steps and arrangement of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principals and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, based upon the description may be employed in other embodiments without departing from the scope of the invention. Accordingly, the following claims are intended to protect the invention broadly, as well as in the specific form shown.
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A boat railing is disclosed wherein the stanchions are connected to the rail by a threaded member internally threaded into both the rail and each respective stanchion. An insert adapted for connection to the threaded member can be movably inserted within the rail to provide adjustable movement about the axis of the rail. A combination of the rotative movements of each stanchion on the threaded member and about the axis of the rail enables the bases of the stanchions to be properly fitted to the surface of the boat irrespective of the slope of the surface to which the base is to be attached.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for optical data transmission between two electrically separated transmitting-receiving units in which transmitting-receiving units have the following features which are that each of the transmitting-receiving units has at least one data transmitter and one data receiver and the first transmitting-receiving unit has a light transmitter for transmission of light energy and the second transmitting-receiving unt has a light receiver for receiving the transmitted light energy and also includes means for converting the light energy into electrical energy and includes means for storing the electrical energy for power purposes.
In a preferred embodiment in the optical bidirectional data transmission equipment such as electric lock systems, one of the two transmitting-receiving untis expediently the key is constructed as a small maintenance free unit. The use of a battery as an internal power supply contradicts this desired object for one of the transmitting-receiving units as it requires that the discharged and dead battery be changed and also makes it necessary to monitor the charged condition of the battery.
So as to be completely independent of the battery, it is desirable to provide an external power supply for one of the transmitting-receiving units expediently the lock, and this external power supply can be constructed with photocells which receive light energy.
A problem arises that both the data as well as the energy for the power supply of the one tansmitting-receiving unit are transmitted with light. Given a data receiver and energy receiving photo element that are spaced closely together, the data information can be in error due to blooming whereby errors result in the data transmission and great accuracy can no longer be assured.
2. Description of the Related Art
German Patent No. 0.075,701, European patent Application No. 0.053,790, U.S. Pat. No. 4,091,734, European Patent No. 0,103,790 and Patent Abstracts of Japan, Vol. 10, No. 386 E-4672443 of Dec. 24, 1986 entitled "Feed Transmission System Using Optical Fiber" all disclose various data transmitting systems of which the disclosures are hereby incorporated by refernce.
SUMMARY OF THE INVENTION
The present invention relates to a method and apparatus for an optical data transmission means wherein one of the transmitting receiving units is supplied with electrical energy by way of photocells in a manner which prevents the transmitted data from being incorrectly received and incorrectly detected due to the transmission of light energy.
An object of the invention is achieved in the following method steps which are performed in succession:
(a) The first transmitting-receiving unit transmit light energy for a predetermined time and this light energy is converted into electrical energy at the second transmitting-receiving unit and is stored for electrical power supply;
(b) The data transmitter of the first transmission-reception unit starts to transmit an auxiliary synchronization pulse during this predetermined time;
(c) The emission of the light energy and of the auxiliary synchronization pulse are simultaneously shutoff; and
(d) The twosimultaneously occurring shut-off edges are detected at the second transmitting-receiving unit and used as a synchronization signal.
It is a feature of the present invention that power is transmitted between two transmitting-receiving units by transmitting light energy from the first transmitting-receiving unit to the second transmitting-receiving which detects such light energy and converts it into electrical energy and then stores it for local pwoer and wherein light energy for power is intermittently transmitted from the first to the second unt and during periods when light energy is not being transmitted, data is transmitted between the units.
Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plot of the signals transmitted between the two transmitting-receiving units as a function of time;
FIG. 2 illustrates a modification of the invention and illustrates the plot of signals transmitted as a function of time;and
FIG. 3 is a block diagram of an exemplary embodiment of the equipment utilized to practice the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 3 illustates the apparatus for practicing the method of the invention which includes a first tansmit-receive station 10 and a second remotely located transmit-receive station 11. The transmit-receive station 10 has an optical data transmitter 12 which receives an input of data to be transmitted at terminal 13 and also an input from a clock 25 and is capable of transmitting data to the remote station 11 which has an optical data receiver 18 which receives the data from the optical data transmitter 12 and supplies it to a storage means 19 which supplies an output to a processing means 21 which supplies an output at terminal 22. The processing means 21 is also connected to optical data transmitter 23 which can receive data at an input terminal 24. A light transmitter 14 is mounted in transmit-receive station 10 and is connected to the clock 25 so as to periodically transmit light energy toa light receiver 26 at the remote staton 11. The light receiver 26 might be a PIN diode, for example, and the light transmitter 14 might be a laser, for example. The light receiver 26 converts the light eergy into electrical energy and supplies it to a capacitor C which serves as the local powe supply for the remote transmitter-receiver 11. The voltage across the capacitor C is connected to the optical data receiver 18, the storage means 19, the processing means 21 and to the optical data transmitter 23 as illustrated.
An optical data receiver 16 in station 10 receives data from data transmitter 23.
The following symbols are used in FIGS. 1 and 2: x 1 chronological course of the light energy sent from the first to the second transmitter-receiver. x 2 voltage across the charging capacitor of the second transmitter-receiver.
x 3 data signal for auxiliary synchronization comprising a pulse sent by the first trasmitter-receiver.
x 4 data signal sent by the second transmitter-receiver. t 0 start of the first light transmission.
t 1 end of the first light transmission and time when the second transmitter-receiver is to receive the end of the data transmission of the first trasmitter-receiver and the beginning of the second light transmission
t 3 beginning of the auxiliary synchronization pulse on the data channel of the first transmitter-receiver
t 4 simultaneous ending of the second light transmission and of the auxiliary synchronization pulse and the simultaneous start of the data transmission from the second to the first trnsmitter-receivers
t 5 end of the data transmission of the second transmitter-receiver.
t 6 beginning of the auxiliary synchronization pulse during the transmission of the first light energy transmission
T 1 a first predetermined time.
T 2 a second predetermined time.
a,b,c data sub-transmissions of the first transmitter-receiver.
d,e,f data sub-transmissions of the second transmitter-receiver.
L,E light energy pulses.
The data transmission equipment required for data transmission according to the method of this invention comprises two transmitter-receiver units each of which is provided with an optical data transmitter and with an optical data receiver. The first transmitter-receiver 10 has a light transmitter 14 for transmission of light energy whichis received by the second transmitter-receiver 11 with the light eceiver 26 which may expediently be one or more photo elements and the light receiver 26 converts the transmitted light energy into electrical energy. The second transmitter-receiver 11 also has means for storing such electrical energy, which might be, for example, a capacitor C. The second transmitter-receiver 11 is supplied with power in this manner. The second transmitter-receiver 11 also contains means for storing 19 and means for processing 21 the received data so that, for example, after the data has been processed, it can again be communicated with the data transmitter 23 to the first transmitter-receiver by using optical transmission.
FIG. 1 illustrates the method of the invention for data transmission as shown by the signal curve as an exemplary embodiment. It is assumed in this exemplary embodiment that the first transmitter-receiver 10 supplies light energy first before it transmits its data to the second transmitter-receiver 11 which receives it with photocells 26. However, it is possible that the data are first transmitted by the second transmitter-receiver 11 which receives the light energy. It is critical in the present invention that the second transmitter-receiver 11 receive adequate light energy before it receives or sends the data, so that a reliable power supply for the second transmitter-receiver, which receives the energy is assured.
FIG. 1 shows in the top row a time plot of x 1 of the light energy sent from the first to the second transmitter-receiver. The emission of the light energy for the first predetermined time T 1 starts at the time t 0 and ends at time t 1 . The received light energy at transmitter-receiver 11 is converted into electrical energy and is stored as the powe suppply in, for example, the capacitor C. After time t 1 , the first transmitter-receiver 10 sends the data that are to be transmitted as a pulse sequence as shown in curve x 3 , in FIG. 1. These data are stored in the second transmitter receiver 11 or are processed therein. The data transmission of the first transmitter-receiver 10 to the second transmitter-receiver 11 is concluded at time t 2 . During data transmission, the second transmitter-receiver 11 is supplied with power from the energy stored in the capacitor C. The voltage on the charging capacitor C is shown in curve x 2 of FIG. 1.
After the data transmissiondescribed, the first transmitter-receiver 10 sends light energy during a second, predetermined time T 2 through time t 4 and this light energy is converted into electrical energy in the second transmitter-receiver 11 and is stored in capacitor C. During time T 2 , the received data can be processed in the second transmitter-receiver 11 and, for example, can be compared to data already contained in a read-only memory, or can be calculated or encoded according to a defined algorithm and the data to be transmitted by the second transmitter-receiver 11 can be identified. This second, predetermined time T 2 is selected such that the processing time and the time needed by the second transmitter-receiver 11 for the calculation of the data is shorter than T 2 .
An auxiliary synchronization pulse is sent out by way of the data transmitter 12 of the first transmitter-receiver 10 during the time T 2 , for example, starting at time t 3 . At time t 4 , the light energy transmission and the data signal are simultaneously shut-off. These two simultaneously appearing shut-off edges identify an unambiguous condition which can be clearly recognized even for an energy receiver and an optical data receiver which are in close proximity. When these two trailing edges of both the energy transmitter 14 as well as the data transmitter 12 of the first transmitter-receiver 10 shut their light off, the second transmitter-receiver 11 knows that the first transmitter-receiver is ready to receive data and data transmission of the second transmitter-receiver 11 which receives energy cancommence. The first and the second transmitter-receiver are thus synchronized. The second transmitter-receiver 11 starts to transmit its data as shown by curve x 4 in FIG. 1. When this data transmission has been concluded at time t 5 , light energy is again transmitted as needed and the procedure starts over again at t 0 .
This synchronization can also be used for the transmissions from the first to the second transmitter-receiver in order to place the second transmitter-receiver 11 in readiness to receive at the proper time. For this purpose, the data transmitter emits light during the first, predetermined time, starting for example at t 6 i.e. between t 0 and t 1 , and this light is simultaneously shut-off together with the shut-off of the energy transmission.
It should be noted here that the first, predetermined time T 1 must be selected to have a length such that a reliable power supply for the second transmitter-receiver 11 is assured.
FIG. 2 illustrates a further example of the manner of energy transmission and of data exchange between the two transmitter-receivers 10 and 11 according to the method of our invention. The method of FIG. 2 differs from FIG. 1, in that data transmission from the first to the second transmitter-receiver i.e. between the times t 1 and t 2 , is subdivided into individual data sub-transmissions periods a, b, c of, for example, one byte each which can be stored in the second transmitter-receiver 11. However, an energy transmission in the form of individual light pulses L from the first to the second transmitter-receiver occurs during the pauses between data subtransmission periods in order to re-charge the capacitor during the pauses. Longer data transmissions times from the first to the second transmitter-receiver can be reliably transmitted without the supply of power in the second transmitter-receiver being depleted. Further, this modification of the invention has the advantage that high power consumption during read-out from the individual memory (for example, an E 2 Prom 2506) contained in the second transmitter unit 23 is sufficient and the minimum voltage needed is available. Although the subdivision of the data transmissoins into individual bytes or bits reduces the data transmission rate, a reliable power supply which has good smoothing of the voltage which is supplied by the capacitor is achieved.
In order to also assure a reliable power supply when sending the data from the second transmitter-receiver 11 to the first transmitter-receiver 10, such data transmission can also be subdivided into individual data sub-transmissions period d, e, f during which pauses energy pulses E are transmitted from the first to the second transmitter-receiver. This is shown in FIG. 2 starting at time t 4 .
As is shown in FIGS. 1 and 2, it is possible with the method of our invention to supply one of the two transmitter-receivers "from the outside" independently of the mains and independently of a battery in an optical, bidirectional data transmission equipment which is accomplished by using optical irradiation of photo elements and also to achieve reliable data transmission. Blooming of the data pulses with light due to the energy transmissions needed for power supply is avoided in that a time separation between data transmission and energy transmission occurs. Since no communication channels in addition to the signal data transmission channel are available, synchronization between the two transmitter-receivers is achieved in a fashion such that an auxiliary synchronization pulse is transmitted on the data transmission channel during the energy transmission, and this auxiliary synchronization pulse is shut-off simultaneously with the energy pulse. Disturbing extraneous light is not present after this simultaneous shut-off and an unambiguous condition is thus achieved which allows reliable synchronization between the first and second data transmission units.
Infrared light is preferably used for the transmission of the light energy and of the data pulses.
The method of our invention can be advantageously used for electronic lock systems. The data transmissoin means can be composed of an electronic lock comprising an electronic key which represent the two transmitter-receivers. The electronic key has infrared diodes and infrared photo elements. The key is introduced into the lock as in conventional lock systems, with the cooperating diodes being mounted in the lock. After checking the diologue with infrared messages between the lock and the key, the lock opens. The power supply of the electronic key is implemented with photo elements.
Although the invention has been described with respect to preferred embodiments, it is not to be so limited as changes and modifications can be made which are within the full intended scope of the invention as defined by the appended claims.
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A method and apparatus for transmitting data between two transmission-receiving units with infrared signals wherein one of the two transmitting receiving units does not have its own power supply and is to be supplied with energy by light received with photocells. When the data receiver and energy receiver are in close proximity, blooming of the data can occur and, thus, faulty data transmission results. In the invention, the data and energy are intermittently and alternately transmitted such that during the energy transmission the data transmitter of the first transmitting receiving unit sends out auxiliary synchronization pulses and after predetermined time both the energy transmission as well as the auxiliary transmission pulses are simultaneously shutoff. The trailing edges of both pulses can be unambiguously recognized even during blooming and are used as a synchronization signal which causes the second transmitting receiving unit to start sending data.
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FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to a variable-key type search device for, and variable-key type search method of, implementing a Random Access Memory (RAM)-Based Binary CAM and a RAM-Based Range Content Addressable Memory (RCAM).
[0002] Conventional memory arrays such as Random Access Memories (RAMs) store and retrieve data units indexed by their respective addresses.
[0003] Content Addressable Memories (CAMs) are associative memories that contain key entries and associated data entries that uniquely correspond to the key entries. A CAM stores the key entries and the associated data entries at any available location and retrieves the associated data for any key that is submitted to be searched in the CAM.
[0004] A binary CAM stores an ordered list of single integer key entries and a corresponding list of their associated data. An RCAM stores instead a list of key entries that represent range boundaries and a list of associated data that correspond uniquely to these ranges. A key search in a binary CAM results in an exact match, whereas a key search in an RCAM matches an entire range. The RCAM also stores a list of associated boundary type entries that determine the validity of the corresponding ranges. This list can be stored in conjunction with the list of associated data or in a separate array.
[0005] A successful approach to utilizing RAM-based technology on a binary CAM is provided in a co-pending, unpublished (and as such, is not to be construed as prior art with regard to the present application) PCT Patent Application Serial No. IL01/00458, which is incorporated by reference for all purposes as if fully set forth herein. A method and apparatus are disclosed therein for the high-rate arrangement, storage and extraction of data in a two-dimensional memory array. The two-dimensional array, which consists of memory cells, is arranged in rows and columns. Each of the key entries in these cells has a unique pair of indices that indicate the key entry location in the array. The associated data entries corresponding to these key entries are stored in another two-dimensional array under the same pair of indices. When a submitted key is searched and found, the associated data is retrieved from the corresponding cell in the other two-dimensional associated-data associated data entry to indicate whether the associated data is valid or not. The key entries in the two-dimensional array are arranged in monotonic order. The entries are arranged in the array so that at least a portion of the array is filled with valid entries, without blanks. The arrays of the key entries and their associated data are kept in perfect sequence by Insert and Remove algorithms.
[0006] The main innovations introduced by this technology include:
[0007] Surrounding the RAM structure with search logic in the RAM periphery: The number of comparator units is proportional to the RAM periphery length rather than to the RAM area. This results in significant savings in the amount of comparator logic, while keeping the memory cell extremely efficient in density and speed. The CAM implementation overhead is typically less than 15%. Therefore, the CAM density obtained with this method is asymptotically close to the comparable size in RAM technology.
[0008] Fast Search Algorithm: The surrounding logic in conjunction with the RAM structure performs searches with the same throughput as a comparable RAM, and twice the latency. Although, in theory, single clock latency may be accomplished, pipelining may yield a better throughput and a similar latency if measured on an absolute time scale (nano-seconds).
[0009] Continuous “Housekeeping” Procedure: Unlike CAMs of the prior art, these CAM devices keep the “house in order”. That is, the deletion of keys does not leave “holes” in the list, which would otherwise require “housekeeping” operations on the managing processor section. Similarly, the addition of new keys keeps the list in a perfect sequence. This “housekeeping” procedure takes longer than the search, but is much faster than required by the system. The overhead associated with the Key List update is significantly shorter when compared with the time taken by the processor to do the housekeeping. This superior performance is due to the efficient RAM and Insert/Remove hardware architecture, which execute very time-efficient algorithms.
[0010] In a co-pending application, U.S. patent application Ser. No. 09/779,941, which is incorporated by reference for all purposes as if fully set forth herein, a method and apparatus are disclosed for arranging and storing a set of key entries and a corresponding set of associated data entries in storage areas within a memory device. Each location in the first storage area is assigned a unique index and is associated with the corresponding location to second storage area with the same index. Each key entry represents a range of consecutive values and is denoted herein as Range Key Entry. The range may be represented by its lower or upper boundary.
[0011] When a key is submitted for search and is found to belong to a range represented by a range key entry, the associated data entry with the same index is extracted from the memory as valid data and a Match signal is issued. If no range is found to contain the submitted key, no valid associated data is retrieved and a No-Match signal is issued.
[0012] In a co-pending, unpublished PCT Patent Application Serial No. IL01/01 025, which is incorporated by reference for all purposes as if fully set forth herein, RAM-based technology is implemented on an RCAM in a somewhat analogous fashion to the above-described implementation of RAM-based technology on a binary CAM. A method and apparatus are disclosed therein for the high-rate arrangement, storage of ranges of integers, and extraction of data associated with these ranges in a two-dimensional memory array. The two-dimensional array, which consists of memory cells, is arranged in rows and columns, each of the key entries (representing range boundaries) in these cells having a unique pair of indices that indicate the key entry location in the array. The associated data entries that correspond uniquely to these ranges are stored in another two-dimensional array under the same pair of indices. When a submitted key is searched and found within an integer range, the associated data is retrieved from the corresponding cell in the other two-dimensional associated-data memory array.
[0013] The RCAM optionally includes a third two-dimensional array, consisting of associated boundary type entries that also correspond uniquely to these ranges and are stored under the same pair of indices. These entries determine the validity of the corresponding ranges. A match signal, “True” or “False”, is output accordingly with the retrieved associated data entry to indicate whether the matched range and the associated data are valid or not. The array of associated boundary type entries can be stored in conjunction with that of associated data entries or separately.
[0014] The key entries in the two-dimensional array are arranged, each entry in a separate cell, in rows or columns, in a subsequent ascending or descending order. The entries are arranged in the array so that at least a portion of the array is filled without blanks with valid entries.
[0015] The technologies (both Binary CAM and RCAM) disclosed by the above-mentioned applications are characterized by fixed-width key entries. For example, RCAM key entries consisting of 32 bits provide a very efficient way of storing address ranges in Classless Inter Domain Routing (CIDR) used in Internet Protocol Version 4 (IPv4), the currently used IP version.
[0016] It would, however, be highly desirable and of further advantage to have a device for, and a method of significantly improving the efficiency and flexibility in the storage and key search operations, by enabling the use of key entries with different widths and types to be efficiently stored in contiguous locations. It would be of even further advantage to have such a system and method adapted for the efficient storage of address ranges in the CIDR used in the new IPv6 protocol.
SUMMARY OF THE INVENTION
[0017] The Variable Key Type Search Engine of the present invention is based on a method and apparatus that enable the use of key entries having different widths and types. Each key entry is composed of a pre-selected number of key fields, and each key field consists of two fixed-width fields: a tag field and a key data field. The tag field indicates the number of key fields that are included in the respective key entry and whether the key data field corresponds to a single integer (like a key entry in a Binary CAM) or to a range of integers (like a key entry in an RCAM). The tag field value also determines the sequential order of the key entries in the list or array, so that key entries of different types may be placed in separate, but preferably contiguous, blocks within the key array. The use of classification tags thus provides great efficiency and flexibility in the storage and key search operations in a single array.
[0018] Using this approach, groups of four 32-bit key data fields can be used for efficient storage of address ranges in CIDR used in the new IPv6 protocol.
[0019] Thus, according to one aspect of the present invention, there is provided a system for storing arranged data in a memory, and for extracting the data therefrom, the system including: (a) a random access memory (RAM) including: (i) a first array of cells, the first array having at least two dimensions and having rows and columns, the first array designed and configured to contain a plurality of at least two kinds of key entries, each of the cells having a unique address and being accessible via an input key, each of the kinds of key entries being arranged in monotonic order, and (ii) a second array of cells, the second array having at least two dimensions and having rows and columns, the second array having a plurality of data entries, each of the data entries being associated with a particular one of the key entries, and (b) processing means designed and configured to search, in response to the input key, the plurality of key entries so as to identify a match.
[0020] According to further features in the described preferred embodiments, the at least two kinds of key entries include a range type key entry, each range type key entry corresponding to a particular range and being associated with a particular one of the data entries.
[0021] According to still further features in the described preferred embodiments, the at least two kinds of key entries include an exact type key entry, each exact type key entry being associated with a particular one of the data entries.
[0022] According to still further features in the described preferred embodiments, the at least two kinds of key entries include range type key entries of differing length, each of the range type key entries corresponding to a particular range and being associated with a particular one of the data entries.
[0023] According to still further features in the described preferred embodiments, the at least two kinds of the key entries include exact type key entries of differing length, each of the exact type key entries being associated with a particular one of the data entries.
[0024] According to still further features in the described preferred embodiments, the at least two kinds of the key entries include a range type key entry and an exact type key entry, each range type key entry corresponding to a particular range and being associated with a particular one of the data entries, each exact type key entry being associated with a particular one of the data entries.
[0025] According to still further features in the described preferred embodiments, at least two of any of the keys are of differing length.
[0026] According to still further features in the described preferred embodiments, the range type key entry contains a single range-boundary value.
[0027] According to still further features in the described preferred embodiments, each of the key entries includes a tag field for differentiating between the kinds of the key entries.
[0028] According to still further features in the described preferred embodiments, each of the key entries includes at least one key field including a key data field and a tag field for differentiating between the kinds of the key entries, and wherein the processing means are designed and configured to search the plurality of the key entries by adding bits of the tag field to bits of the key data field to form a single binary number.
[0029] According to still further features in the described preferred embodiments, each of the key entries includes a plurality of key fields including a plurality of key data fields and at least one tag field for differentiating between the kinds of the key entries, and wherein the processing means are designed and configured to search the plurality of the key entries by adding bits of the tag field to bits of the key data fields to form a single binary number.
[0030] According to still further features in the described preferred embodiments, each of the key entries includes at least one key field including a key data field and a tag field for differentiating between the kinds of the key entries, and wherein the processing means are further designed and configured to add at least one bit of the tag field to bits of the key data field to form a single binary number for use in the search.
[0031] According to still further features in the described preferred embodiments, each of the key entries includes a tag field for differentiating between the kinds of the key entries, each tag field having a tag field value, and wherein the processing means are further designed and configured to position a particular one of the key entries within the first array, based on the tag field value.
[0032] According to still further features in the described preferred embodiments, each of the key entries includes a tag field for differentiating between the kinds of the key entries, each tag field having a tag field value, and wherein the processing means include identification means for identifying, within the first array, a row that may contain a match between a particular one of the key entries and the input key, based on the tag field value.
[0033] According to still further features in the described preferred embodiments, the identification means for identifying a row within the first array include at least one comparator.
[0034] According to still further features in the described preferred embodiments, the identification means further include a column locator for comparing contents of the row with the input key so as to identify a column containing a match for the input key.
[0035] According to still further features in the described preferred embodiments, the column locator includes at least one comparator.
[0036] According to still further features in the described preferred embodiments, the tag field is disposed in relation to the key field such that at least one most significant bit (MSB) position is occupied by at least one bit of the tag field.
[0037] According to a second aspect of the present invention, there is provided a method for storing arranged data in a memory, and for extracting the data therefrom, the method including the steps of: (a) providing a system including: (i) a random access memory (RAM) including: (A) a first array of cells for storing key entries, the first array having at least two dimensions and having rows and columns, each of the cells having a unique address and being accessible via an input key, and (B) a second array of cells, the second array having at least two dimensions and having rows and columns, the second array having a plurality of data entries, each of the data entries being associated with a particular one of the key entries, and (ii) processing means associated with the RAM, and (b) storing at least a first kind and second kind of the key entries within the first array.
[0038] According to further features in the described preferred embodiments, the at least a first kind and second kind of key entries are arranged in monotonic order.
[0039] According to still further features in the described preferred embodiments, the first kind of key entries is arranged in a first block of cells within the first array, and the second kind of key entries is arranged in a second block of cells within the first array.
[0040] According to still further features in the described preferred embodiments, the blocks of cells are arranged in a substantially contiguous fashion.
[0041] According to still further features in the described preferred embodiments, the method further includes the step of: (c) searching, in response to the input key, a plurality of key entries so as to identify a match.
[0042] According to still further features in the described preferred embodiments, the at least one kind of key entries is a range type key entry.
[0043] According to still further features in the described preferred embodiments, the at least one kind of key entries is an exact type key entry.
[0044] According to still further features in the described preferred embodiments, the at least one kind of key entries is an exact type key entry.
[0045] According to still further features in the described preferred embodiments, each of the key entries includes a tag field.
[0046] According to still further features in the described preferred embodiments, each of the key entries includes a tag field and a key data field, and wherein the searching includes differentiating between the kinds of key entries.
[0047] According to still further features in the described preferred embodiments, the tag field and the key data field are examined as a single binary number in step (c).
[0048] According to still further features in the described preferred embodiments, the first kind of key entries is arranged in a first block of cells within the first array, and the second kind of key entries is arranged in a second block of cells within the first array.
[0049] According to still further features in the described preferred embodiments, the searching includes identifying a matching kind of the key entries using the tag field.
[0050] According to still further features in the described preferred embodiments, the searching includes identifying a row within the first array in which a key entry matching the input key may be disposed.
[0051] According to still further features in the described preferred embodiments, the searching includes identifying a row within the first array in which the input key may fall within a particular range associated with a range type key entry.
[0052] According to still further features in the described preferred embodiments, the searching includes disposing the tag field in relation to the key field such that at least one most significant bit (MSB) position is occupied by at least one bit of the tag field.
[0053] According to still further features in the described preferred embodiments, the storing of the key entries includes varying a length of the tag field according to a pre-determined criterion, so as to reduce a number of the cells occupied by the tag field.
[0054] According to still further features in the described preferred embodiments, the method further includes disposing the tag field in a most significant bit (MSB) position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
[0056] In the drawings:
[0057] [0057]FIG. 1 is a schematic illustration of a two-dimensional, M-column by N-row, memory array;
[0058] [0058]FIG. 2 is a schematic illustration of key mapping in a conventional RAM of the prior art;
[0059] [0059]FIG. 3 is a schematic illustration of the correspondence between the two-dimensional key list and the associated data list for a binary CAM;
[0060] [0060]FIG. 4 is a schematic illustration of the correspondence between the two-dimensional key list, the associated data list and the associated boundary type list;
[0061] [0061]FIG. 5 illustrates a generic key field and three key entries containing 1, 2 and 4 key fields, respectively;
[0062] [0062]FIG. 6 illustrates width relations of the three key entries provided in FIG. 5;
[0063] [0063]FIG. 7 illustrates a two-dimensional array, partially filled with contiguous blocks of key entries of decreasing width;
[0064] [0064]FIG. 8 provides examples of tag fields in a key entry word and structure of a three-bit tag field;
[0065] [0065]FIG. 9 illustrates step 1 (Row Location) in a Sequential Key Search in a TDA, and
[0066] [0066]FIG. 10 illustrates step 2 (Column Location) in a Sequential Key Search in a TDA.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0067] The principles of the variable-key type search system for, and variable-key type search method of, implementing a Random Access Memory (RAM)-Based Binary CAM and a RAM-Based Range Content Addressable Memory (RCAM), according to the present invention, may be better understood with reference to the drawings and the accompanying description.
[0068] 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 the arrangement of the components set forth in the following description or illustrated in the drawing. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
[0069] 1. RAM-Based Binary CAM or RCAM—Basic Concepts
[0070] One basic concept underlying the RAM-Based Binary CAM or RAM-Based RCAM is maintaining an ordered key list. This means that the key entries are stored in such a way that:
[0071] The key entries are positioned contiguously in either an ascending or descending order in a multi-dimensional memory array
[0072] The empty locations in the memory array are contiguous, and may either follow or precede the occupied locations, with a uniquely defined transition point between the last occupied location and the first empty location, or vice versa
[0073] The block of occupied locations may either start at the first memory address or end in the last memory array address
[0074] Although the RAM-Based Binary CAM or RCAM may be implemented using any of the alternatives described above, we shall limit our discussion to the following exemplary cases:
[0075] The key entries are stored in contiguous ascending order in two-dimensional arrays (TDAs)
[0076] The key list starts at the lowest memory array address
[0077] The block of empty positions follows the key list
[0078] [0078]FIG. 1 depicts a TDA of M columns by N rows. The rows are sequenced from top to bottom and indexed with an integer index j, where 0≦j≦N−1. The columns are sequenced from left to right and indexed with an integer index i, where 0≦i≦M−1. The occupied key entry locations are shadowed with light gray. The empty locations are blank. A key located in column i and row j has an integer value Ki,j. The lowest key value K 0,0 resides in row 0 and column 0. The highest key value K U,V resides in row V and column U.
[0079] The TDA parameters are:
[0080] b: Key data width
[0081] M: Number of TDA columns, or number of b-bit wide key words in a TDA row
[0082] N: Number of TDA rows
[0083] U: Last key entry column
[0084] V: Last key entry row
[0085] j: Key row index, 0≦j≦V
[0086] i: Key column index, 0≦I≦M−1 for j≦V and 0≦I≦V for j=V
[0087] The RAM organization is depicted in FIG. 2.
[0088] The RAM parameters are:
[0089] w: Width of the RAM word and of the RAM data bus
[0090] δ 0 -δ w−1 : RAM word bus, where δ 0 is defined as the word rightmost bit, and δ w−1 , is the word leftmost bit
[0091] P: Number of w-bit wide words in the RAM
[0092] Adr 0 -Adr k−1 : k-bit wide RAM address bus
[0093] Then, each w-bit wide RAM word contains M key words, that is,
w=M·b
[0094] The RAM-Based Binary CAM contains two TDAs or lists, a key list and an associated data list. Each key entry K i,j has a corresponding associated data entry D i,j , as depicted in FIG. 3. Since the Binary CAM stores an ordered list of single integer keys, a key search in results in an exact match and a straightforward access to the corresponding associated data.
[0095] The RAM-Based RCAM includes additionally an associated boundary type list, where each associated boundary type entry M i,j corresponds to the key entry K i,j as shown in FIG. 4. The RCAM stores a list of key entries that represent boundaries of associative ranges, so that a key search results in a matching range, and the retrieval of the associated data and boundary type that corresponds uniquely to this range. The associated boundary type determines the validity of the matching range and the associated data.
[0096] The entries of the key list, associated data list and associated boundary type list (for an RCAM) are always kept in a compact and sequential form (monotonically increasing or decreasing), and perfect correspondence, by means of efficient Insert and Remove algorithms.
[0097] 2. Variable Key Type Search Engine—Basic Architecture and Operations
[0098] One basic component that promotes the flexibility and efficiency of the inventive Variable Key Type Search Engine is a tag field indicator for indicating:
[0099] 1) the number of key fields (tag plus key data fields) included in each respective key entry, and
[0100] 2) the type of key data field (a single integer as in a Binary CAM, or a range of integers as in an RCAM).
[0101] The tag field value is also used to determine the sequential order of the key entries in the list or array, so that key entries of different types may be placed in separate but contiguous blocks within the key array. Various arrangements may be apparent to those skilled in the art. For example:
[0102] The key entries may be arranged in contiguous blocks of either increasing or decreasing width, which depends on the number of key fields in a key entry.
[0103] A compact arrangement requires starting either with the largest key entries at the first array index (0,0) for decreasing width or at the last array index (M−1, N−1) for increasing width. In either case, the number of bits of any key entry, except the smallest key entry (one key field), must be a multiple of the number of bits of the contiguous smaller key entry.
[0104] The key entries may be arranged according to their types of key data field (a single integer leading to an exact match or a range of integers leading to a matching range).
[0105] A general requirement, regardless of the type of arrangement, is that the width of the key entries must be pre-selected considering the width of the RAM word, so that the key entries fill exactly every row of the TDA.
[0106] Although the Variable Key Type Search Engine may be implemented in any of the alternatives described above, we shall discuss the following case:
[0107] The key entries are arranged in contiguous blocks of decreasing width starting with the largest key entries at the first array index (0,0).
[0108] Each key entry may contain 1, 2 or 4 key fields of 36 bits. Each 36-bit key field consists of a 4-bit tag field and a 32-bit key data field.
[0109] [0109]FIG. 5 depicts a generic key field and then three key entries containing 1, 2 and 4 key fields. The data provided in a key entry with several key fields is distributed in the key data fields with the most significant bits (MSBs) in the leftmost key field and the least significant bits (LSBs) in the rightmost key field. The tag fields are identical for all the key fields in the same key entry.
[0110] The key entry parameters are:
[0111] n: Number of key fields in a key entry
[0112] k: Key entry with n key fields
[0113] m: Number that indicates the position of each key field in a key entry, starting from zero for the field with the LSB
[0114] f m n : Key field in position m in key entry k n
[0115] t n : Tag field in key entry k n . This parameter is identical for all the key fields in the same key entry, and therefore is independent of m
[0116] b m n : Key data field in position m in key entry k n
[0117] [0117]FIG. 6 depicts the width relations of three key entries containing 1, 2 and 4 key fields. The width parameters of the key entry and key field are:
[0118] w k n : Width of a key entry with n key fields
[0119] w f : Key field width
[0120] w t : Tag field width
[0121] w b : Key data field width
[0122] The width or number of bits of a key field is the sum of the number of bits of its tag and key data fields:
w
f
=w
t
+w
b
[0123] The widths of the key field, tag field and key data field, w f , w t and w b , respectively, are fixed.
[0124] The number of bits in a key entry is a multiple of the number of bits in its key fields:
w k n =n·w f =n ·( w t +w b )
[0125] Since the key entries must fill every TDA row (corresponding to a RAM word), the number of bits n of any key entry, except the smallest key entry (for a one key field), must be a multiple of the number of bits of the contiguous smaller key entry, and the sum of bits of all the key entries in every row must equal the RAM word width:
w = ∑ i = 1 K w k n ( i ) = w f · ∑ i = 1 K n i = ( w t + w b ) · ∑ i = 1 K n i
[0126] where w is the width of the RAM word, K is the number of key entries in a row and n i is the number of key fields in a specific key entry.
[0127] If all the key entries in a row have the same number n of key fields, then:
w=K·w k n =K·n·w f =K·n ·( w t +w b )
[0128] Thus, since w k n is a multiple of the number of bits in any key fields, including the largest key entry, the total number of bits in a row is clearly a multiple of the number of bits in the largest key entry.
[0129] [0129]FIG. 7 depicts a TDA partially filled with contiguous blocks of key entries of decreasing width starting with the largest key entries at the first array index (0,0). The key entries in these blocks contain 4, 2 and 1 key fields, and are shown in alternate gray and white colors, and with different filling patterns for the key entries with different widths.
[0130] The width of each key entry, which depends on the number of key fields integrated in it, is determined by the two more significant bits of the tag field. Since, in this particular example, the values of the RSE key entries are stored in ascending order, the more significant bits of the tag field must be specified so that larger key entries are represented by smaller numbers. (If the TDA were arranged with contiguous blocks of key entries of increasing width, the more significant bits of the tag field would be specified so that smaller key entries are represented by smaller numbers).
[0131] The LSB of the tag field indicates whether the key data field corresponds to a single integer (leading to an Exact Match in a Binary CAM) or to a range of integers (leading to a Range Match in an RCAM). In this way, the key entries of the same width are grouped according to their type. Within these groups, the key entries are stored in contiguous ascending order according to the values of the key data fields starting from their MSBs.
[0132] Thus, this tagging method allows, by storing contiguous blocks of key entries in ascending order, a Search operation for lookups, and Insert and Remove operations for the maintenance of the TDA in order, using the same procedures as in RAM-Based Binary CAMs and RAM-Based RCAMs described in PCT Patent Application Serial No. IL01/00458 and PCT Patent Application Serial No. IL01/01025, respectively.
[0133] In a preferred implementation, the structures of the Associated Data TDA and Associated Boundary Type TDA (for RAM-Based RCAM) correspond identically to that of the Key TDA. In this case, when a key entry is composed of more than one key field, the corresponding associated data entry and the associated boundary type entry (for RAM-Based RCAM) are also composed of the same number of fields; however, these fields contain data only and no tags. All the fields in the associated data and boundary type entry can be used to store data; if only one field suffices, the field corresponding to the more significant bits may be used.
[0134] If all the key entries in a device are known to have the same length, an alternative implementation may be used with the associated data and associated boundary type entries having each one data field only.
[0135] The storage of Ipv4 CIDR, Multicast and IPv6 CIDR addresses requires 32, 64 and 128 bits, respectively. Key entries with 1, 2 and 4 key data fields of 32 bits can be used for this purpose. If 32 bits are assigned to the key field and 3 bits to the tag field, then a field key consists of 35 bits, because:
w b =32
w t =3
w f =w t +w b =35
[0136] Key entries with 1, 2 and 4 field keys, consisting of 35, 70 and 140 bits, respectively, can be used to store Ipv4, Multicast and IPv6 CIDR addresses:
w k 1 =1 ·w f =35
[0137] for Ipv4 CIDR
w k 2 =2 ·w f =70
[0138] for Multicast addresses
w k 4 =4 ·w f =140
[0139] for IPv6 CIDR addresses
[0140] In order to fill a TDA row, the RAM word width must be a multiple of the number of bits in the largest key entry, i.e., a multiple of 140. Thus, any RAM having words with a number of bits equal to 140, 280, 420, 560, etc., can serve for this purpose.
[0141] As an example, a single Range Search Engine (RSE) or multiple RSEs integrated into a single Forwarding Information Base (FIB) implemented with such RAMs can be used to store six key types several key types:
[0142] 140-bit Range Type Keys
[0143] 140-bit Exact Type Keys
[0144] 70-bit Range Type Keys
[0145] 70-bit Exact Type Keys
[0146] 35-bit Range Type Keys
[0147] 35-bit Exact Type Keys
[0148] This selection requires only a 3-bit tag field, which provides up to 2 3 =8 key types. Table 1 shows an optional way of tagging the six key types listed above. Two bits are used for the Tag Length (TGL) and one for the Exact/Range selection. The two unused combinations TGL=00, E/{overscore (R)}=0 and 1, can provide additional selections.
TABLE 1 Tagging of Six Key Types TGL E/R Key/Type 01 0 140-bit, Range Type 01 1 140-bit, Exact Type 10 0 70-bit, Range Type 10 1 70-bit, Exact Type 11 0 35-bit, Range Type 11 1 35-bit, Exact Type
[0149] Assume, by way of example, that the 32-bit binary number 00110011011110000000011110000000 is stored in a Key TDA, first as the key data of the fourth key field (the one with the less significant bits) in a 140-bit Range Type Key, then as the key data of the second key field in a 70-bit Range Type Key and finally as the sole key data field of a 35-bit Exact Type Key. The tag field, composed of two TGL bits followed by one E/{overscore (R)} bit, as shown in Table 1, is 010 for the 140-bit Range Type Key, 100 for the 70-bit Range Type Key, and 111 for the 35-bit Exact Type Key.
[0150] Thus, when the 32-bit number 00110011011110000000011110000000 is stored as the fourth key data field in a 140-bit Range Type Key, the 3 bits 010 appear in the tag field, so that the fourth key field consists of 010+00110011011110000000011110000000. The other three key fields in the 140-bit Range Type Key include each the same tag field 010 but different 32-bit numbers as key data fields. The tag fields of the three less significant key fields are redundant and disregarded when the key fields are integrated into a single number for search and maintenance operations (to keep the Key List in order); this number consists of one tag field followed by four key data fields, i.e., in this example it includes 3+32×4=131 bits.
[0151] When the 32-bit number 00110011011110000000011110000000 is stored as the second key data field in a 70-bit Range Type Key, the 3 bits 100 appear in the tag field, so that the second key field consists of 100+00110011011110000000011110000000. The other key field in the 70-bit Range Type Key includes the same tag field 100 but a different 32-bit number as a key data field. The tag fields of the less significant key field is redundant and disregarded when the key fields are integrated into a single number for search and maintenance operations; this number consists of one tag field followed by four key data fields, i.e., in this example, it includes 3+32×2=67 bits.
[0152] When 00110011011110000000011110000000 is stored as the key data field in a 35-bit Exact Type Key, the 3 bits 111 appear in the tag field, so that the sole key field (and the entire 35-bit Exact Type Key) consists of 111+0011001101001100000001110000000, i.e., 3+32=35 bits.
[0153] Another optional method that provides great flexibility uses tags of a variable length, from 0 to 3 bits, that occupy the most significant bit positions in every key entry word. In this arrangement, the Tag Length (TGL) configuration field defines the number bits included in the tag field, as shown in FIG. 8; the longer the tag field, less bits are available for the key data. The key field shown consists of 35 bits. As the the tag field width increases from 0 to 3 bits, the key data field width decreases from 35 to 32 bits. The key entry shown at the bottom of the figure consists of one key field. The 3-bit tag field conforms with the tagging method shown in Table 1. The 32-bit key data field can be used to represent an IPv4 address.
[0154] Key Search in the Key List
[0155] When a key is submitted for a search (lookup), its tag field, determined by its predefined length and type, is added to the key data field (or fields) as described above; then, integrated as one key with one or more fields, the submitted key is searched in the Key TDA, in the same way as a single-field key is searched in a TDA with untagged single-field key entries. The search procedure for the RAM-Based Binary CAMs and RAM-Based RCAMs is described below.
[0156] Two-Step Search Algorithm
[0157] A sequential search of the submitted key (Key Search) in the TDA can be completed in two steps:
[0158] Step 1: Identification of the TDA row where the submitted key may be located, as illustrated in FIG. 9. This step is identical for Binary CAMs and RCAMs.
[0159] Step 2: Access to the row identified in Step 1 and lookup of the submitted key, to find an exact match (for a Binary CAM) or a range match (for an RCAM), as illustrated in FIG. 10. This step is different for Binary CAMs and RCAMs.
[0160] Prior to the Key Search in the Key List, the submitted key K is compared with the Key List values in the first and last locations. If K<K 0,0 or K>K U,V , the search is concluded, as the key is not included in the Key List.
[0161] If K 0,0 ≦K≦K U,V , the key is potentially listed in the Key List. In this case, the search procedure can start with Step 1.
[0162] The Search procedures essentially identical to those used in RAM-Based Binary CAMs and RAM-Based RCAMs, described in PCT Patent Application Serial No. IL01/00458 and PCT Patent Application Serial No. IL01/01025, respectively.
[0163] In the serial two-step search algorithm, a new search cycle starts only after the search cycle for the previous key is completed; thus, two clocks are required for execution, such that the search is performed at half of the clock rate.
[0164] In the pipelined search algorithm, a new search cycle starts after the first step of the previous search cycle is completed, i.e., just one clock period after the start of the previous cycle; thus, search operations are performed at a full clock rate.
[0165] Keeping the Key List in Order—Insert and Remove Operations
[0166] The insertion or removal of keys demands constant updating of the Key List to keep it in order. The straightforward way to update the keys is by applying a serial and lengthy algorithm that requires sequential readout and update of all the Key List entries. The Insert and Remove procedures for the maintenance of the TDA in order are based on the fact that the TDA structure is implemented with a w-bit wide RAM. Since each RAM word consists of M keys, the Key List can be readout and written in steps of M keys.
[0167] The Insert and Remove operations are similar for RAM-Based Binary CAMs and RAM-Based RCAMs, and are described in PCT Patent Application Serial No. IL01/00458 and PCT Patent Application Serial No. IL01/01025, respectively.
[0168] As used herein in the specification and in the claims section that follows, the term “kind of key entry” and the like refer to a type of key entry such as an exact type key entry or a range type key entry, or to a key entry of a particular length. Thus, an exact type key entry and a range type key entry are defined to be two kinds of key entries, and a 35-bit exact type key entry and a 140-bit exact type key entry are also defined to be two kinds of key entries. The key entry typically includes a key field and a tag field that characterizes the length and/or type of the key entry.
[0169] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.
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A system and method for storing arranged data in a memory, and for extracting the data therefrom, the system including: (a) a random access memory (RAM) including: (i) a first array of cells, the first array having at least two dimensions and having rows and columns, the first array designed and configured to contain a plurality of at least two kinds of key entries, each of the cells having a unique address and being accessible via an input key, each of the kinds of key entries being arranged in monotonic order, and (ii) a second array of cells, the second array having at least two dimensions and having rows and columns, the second array having a plurality of data entries, each of the data entries being associated with a particular one of the key entries, and (b) processing means designed and configured to search, in response to the input key, the plurality of key entries so as to identify a match.
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This is a continuation of application No. 07/578,484 filed Sep. 20, 1991, now abandoned.
BACKGROUND OF THE INVENTION
The present device relates to an engine starter, particularly to the improvement of a braking current restriction means for an electric motor for starting an engine.
There is known an engine starter disclosed in the Japanese Utility Model Application No. 8696/89. The engine starter is described with reference to FIG. 1. The engine starter 1 is a magnet-employing starter of the electromagnetic push-in type and includes a DC motor 2 and an electromagnetic switch 3 attached to the motor. The DC motor 2 includes a permanent magnet having magnetic poles 4 for driving an armature 5 of the motor, and plus and minus brushes 6 and 7 disposed in slip contact with the armature. The electromagnetic switch 3 includes a main contact unit 8 consisting of a pair of fixed contacts 9a and 9b and a movable contact 11, which is put into and out of touch with the fixed contacts by a movable iron core 10, a pair of normally-closed fixed contacts 12a and 12b opposed to the movable contact 11, a current coil 13 for attaching the movable iron core 10, and a voltage coil 14 for keeping the iron core attracted. The 16. The normally-closed fixed contact 12a is grounded. The current coil 13 and the plus brush 6 are grounded when the electromagnetic switch 3 is de-energized. The other normally-closed fixed contact 12b is connected to the current outgoing terminal 17 of the current coil 13 and to the normally open fixed contact 9b .
Since the field means of the DC motor 2 of the conventional engine starter 1 described above entirely made of the permanent magnet 4, a high voltage is generated between the plus and the minus brushes 6 and 7 when the armature 5 is inertially rotated in the magnetic field of the permanent magnet. Besides, since the brushes 6 and 7 are grounded at that time, a braking current of excessive magnitude flows so that the contacts are fuse-bonded, the components of the electromagnetic switch 3 are thermally deteriorated and the armature 5 is abruptly stopped making a loud noise. These are problems.
It is an object of the present invention to provide an engine starter in which a braking current generated due to the inertial rotation of an armature is restricted.
In accordance with the above object the invention provides an engine starter comprising an electric motor for starting an associated engine when the motor is energized, and an electromagnetic switch including a pair of normally opened contacts connected to each other to form an energizing circuit for the motor at the time of energizing a coil of the switch, and a pair of normally closed contacts connected to each other to form a grounding circuit through a restrictive output device for said motor at the time of de-energizing the coil. A first restriction means restricts the kinetic energy generated due to the inertial rotation of the armature, and a second restriction means restricts a braking electrical current due to the rotation of the armature in a magnetic field. The first restriction means includes a permanent magnet and at least one pair of electromagnets neighboring each other. The second restriction means includes the restrictive output device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a wiring diagram of a conventional engine starter.
FIG. 2 is a wiring diagram of an engine starter which is an embodiment of the present device.
FIG. 3 is a wiring diagram of an engine starter which is another embodiment of the present device.
FIG. 4 is a wiring diagram of an engine starter which is yet another embodiment of the present device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention will now be described with reference to the drawings. FIG. 2 shows an engine starter 20 which is one of the embodiments according to present invention. The engine starter according to the present invention is composed of substantially the same components as those shown in FIG. 1 except for the parts described hereinbelow. Accordingly, the duplicated description will be omitted. The engine starter 20 includes an electromagnetic switch 3 and a DC motor 21 having a four-pole field device 22 made of a pair of mutually-neighboring electromagnets 22a and 22b and a pair of mutually-neighboring permanent magnets 22c and 22d. The electromagnet 22a has south pole opposed to the armature 5 of the DC motor 21. One terminal of the coil of the electromagnet 22a is connected to fixed contact 9b, and the other terminal of the coil is connected to one terminal of the coil of the other electromagnet 22b connected to a plus brush 6. A minus brush 7 is grounded.
When the armature 5 begins to inertially rotate, only the portion of the coil of the armature, which is located in the magnetic fields of the permanent magnets 22c and 22d of the field device 22, receives an electromagnetic braking action and a braking current generated due to the inertial rotation of the armature is consequently made less than that in the conventional engine starter. When the DC motor 21 is de-energized by disconnecting normally-open contact 9a and 9b from each other, the electrical currents in the field coils of the electromagnets 22a and 22b are nearly instantaneously made zero so that no magnetic field is applied to the inertially rotating armature 5 by the electromagnets 22a and 22b. For that reason, nearly no electromagnetic braking force generated by the electromagnets 22a and 22b is applied to the armature 5.
FIG. 3 shows a starter 120 which is another embodiment of the present invention. The engine starter according to the present invention is composed of substantially the same components as those shown in FIG. 1 except for the parts described hereinbelow. Accordingly, the duplicated description will be omitted. The engine starter 120 includes an electromagnetic switch 121 and a DC motor 2. The switch 121 includes an output device 122 connected between a normally-closed fixed contact 12a and ground so as to make a sound.
When the armature 5 of the engine starter 120 begins to inertially rotate, a braking current is generated in the coil of the armature because of the rotation thereof in the magnetic fields of a pair of permanent magnets 4 constituting the field device of the DC motor, so that an electromagnetic braking force acts to brake the rotation of the armature thereof. At that time, the braking current flows from the coils of the armature 5 to the output device 122 so that the sound is made. Since the output device 122 acts as a resistor to the braking current, the current is made much less than in the case when the current flows directly into the ground. Thus, the electromagnetic braking force which acts on the armature 5 is reduced so that the armature is prevented from being abruptly stopped. Besides, an unpleasant noise made at the time of the stoppage of the armature 5 is overwhelmed by the sound made by the output device 22.
FIG. 4 shows a starter 230 which is another embodiments of the present invention and is composed of substantially the same components as those shown in FIG. 1 except for the parts described hereinbelow. Accordingly, the duplicated description will be omitted. The engine starter 230 includes an electromagnetic switch 121 and a DC motor 231. The DC motor 231 includes a four-pole field device 32 made of a pair of mutually-neighboring electromagnets 232a and 232b and a pair of mutually-neighboring permanent magnets 232c and 232d. The electromagnet 232a has a south pole opposed to the armature 5 of the DC motor 231. One terminal of the coil of the electromagnetic 232a is connected to a fixed contact 9b, and the other terminal of the coil is connected to one terminal of the coil of the other electromagnet 232b, the other terminal of the coil of which is connected to a plus brush 6. An minus brush 7 is grounded.
When the armature 5 of the engine starter 230 begins inertially rotate, only the portion of the coil of the armature 5, which is located in the magnetic fields of the permanent magnets 232c and 232d of the field device 32, receives an electromagnetic braking action and a braking current generated due to the rotation of the armature flows through an output device 122 so that the current is made very small. When the DC motor 231 is de-energized by disconnecting normally-open contacts 9a and 9b from each other, the electrical currents in the field coils of the electromagnets 232a and 232b are nearly instantaneously made zero so that no magnetic field is applied to the inertially rotating armature 5 by the electromagnets. For that reason, nearly no electromagnetic braking force is applied to the inertially rotating armature 5 by the electromagnets 232a and 232b. In addition, the output device 122 acts as a resistor to the braking current as the current flows from the coil of the armature 5 to the output device, so that a sound is made by the device.
Since the braking current generated due to the inertial rotation of the armature 5 of the engine starter 230 is, thus restricted to be very small, the contact are prevented from being fuse-bonded, the components of the electromagnetic switch 121 are not thermally deteriorated and the armature is not abruptly stopped. Beside, a noise made at the time of the stoppage of the armature 5 is overwhelmed by the sound made by the output device 122. Therefore, the engine starter 230 is enhanced in quality.
In an engine starter of the present invention, an output device for making a sound is connected between a normally-closed fixed contact and ground so as to restrict a braking current generated due to the inertial rotation of an armature. For that reason, the contacts are prevented from being fuse-bonded, the components of a switch are not thermally deteriorated and the armature is not abruptly stopped. Besides, an unpleasant noise made due to the stoppage of the armature is overwhelmed by the sound made by the output device.
In another engine starter of the present invention, an electrical current is generated in the coil of an armature when the armature inertially rotates across the magnetic field of the permanent magnet of a field device. For that reason, an electromagnetic braking force acts to the armature to brake the rotation thereof. Since an output device for making a sound acts as a resistor to the electrical current generated in the coil of the armature, the current is reduced. For that reason, the electromagnetic braking force which acts on the armature is restricted so that the armature is prevented from being abruptly stopped. Besides, an unpleasant noise made due to the stoppage of the armature is overwhelmed by the sound made by the output device.
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An engine starter comprises an electric motor for starting an engine when the motor is energized, an electromagnetic switch including a pair of normally-open contacts connected to each other to form an energizing circuit for the motor at the time of energizing a coil of the switch, and a pair of normally-closed contacts connected to each other to form a grounding circuit for the motor at the time of de-energizing of said coil, and a restriction device for restricting a braking electrical current generated due to an inertial rotation of the motor.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The present invention relates to storage area networks, and more particularly to using elements in storage area network to manage cluster membership of hosts attached to the storage area network.
[0003] 2. Description of the Related Art
[0004] Demand for higher performance computer systems is never ending. Increased performance is demanded at both the host processing side and at the storage side. to improve performance and flexibility of the connection between hosts and storage units, storage area networks (SANs) have developed. SANs provide the capability to flexibly connect hosts to storage, allowing improved performance while reducing costs. The predominate SAN architecture is a fabric developed using Fibre Channel switching. Fibre Channel is a series of ANSI standards defining a high speed communication interface. One property of Fibre Channel is that links can be point to point. When the devices are interconnected by a series of switches, a fabric is formed. The fabric allows routing communications between the various connected devices.
[0005] In addition to high performance connections between the hosts and the storage units, a second technique used to increase system performance is clustering of the hosts. By interconnecting hosts, they can work together on the various tasks of a common program. This technique requires high speed communications between the hosts to manage the operations. These communications can occur using numerous networking protocols, such as Ethernet, Fibre Channel, InfiniBand or Myrinet.
[0006] However, several problems occur when clustering hosts, which limits the performance gains available. A first problem is cluster membership management. Every host (or node as often called) needs to understand the group of valid members of the cluster. There is significant overhead and network associated with this activity, particularly as the number of nodes grows. Simplistically, each node must periodically communicate with each other node, which generates traffic and requires processing by the node, both when sending and when receiving. Then, if a node senses a problem, all of the nodes need to reach consensus on the cluster membership. This consensus process is time consuming and also generates additional network traffic. So it would be desirable to improve the membership management of a cluster to eliminate much of the processing overhead, traffic and consensus-building.
[0007] A second problem is resource sharing. Usually the various nodes will share various resources. But also usually only one node at a time can access the resource. This is addressed by locking the resource when a node has control. When using locking to gain control of the resource, the node performs an operation on the lock to determine if another node has control. If not, the node gains control. If another node has control, the requesting node continues to perform the operation until successful Thus traffic over the network is generated to handle the lock operation. Usually this is traffic between nodes because a node is used to implement the shared memory used to form the lock. So this further hinders performance by frequent accesses to the node and creates overhead sending and receiving the operations. The problem becomes significant in most systems because there are a large number of locks that must be implemented, with a large number of nodes vying for control. It would be desirable to limit traffic and overhead required to maintain resource locks.
SUMMARY OF THE INVENTION
[0008] The preferred embodiments according to the present invention provide the capability to manage the cluster membership and to provide and manage locks in the switches forming the network.
[0009] To manage the cluster membership, a zone is created, with indicated members existing in the zone and the zone being managed by the switches. The nodes communicate their membership events, such as heartbeat messages, using an API to work with the switch to which they are attached. The desired membership algorithm is executed by the switches, preferably in a distributed manner. Each switch then enforces the membership policies, including preventing operations from evicted nodes. This greatly simplifies the programs used on the nodes and unburdens them from many time consuming tasks, thus providing improved cluster performance.
[0010] In a like manner, the switches in the fabric manage the resource locks. The nodes send their lock requests, such as creation and ownership requests, to the switch to which they are connected using sample common transport layer commands. The switches then perform the desired lock operation and provide a response to the requesting node. Again, this greatly simplifies the programs used on the nodes and unburdens them from many time consuming activities, providing improved cluster performance.
DESCRIPTION OF THE DRAWINGS
[0011] [0011]FIG. 1 illustrates a system diagram of a Fibre Channel network with a zone in an embodiment of the present invention.
[0012] [0012]FIG. 2 is a block diagram of a system indicating an example of the connections within a Fibre Channel fabric according to an embodiment of the present invention.
[0013] [0013]FIG. 3 is a more detailed block diagram of switches according to an embodiment of the present invention.
[0014] [0014]FIG. 3A is a block diagram of a node according to an embodiment of the present invention.
[0015] [0015]FIG. 4A is a block diagram of one embodiment of a principal switch suitable for cluster membership and lock management in accordance with the present invention.
[0016] [0016]FIG. 4B is a block diagram of one embodiment of a local switch suitable for cluster membership and lock management in accordance with the present invention.
[0017] [0017]FIG. 5 is a flowchart of node operations according to the present invention.
[0018] [0018]FIG. 6 is a flowchart of principal switch operations according to the present invention.
[0019] [0019]FIG. 7 is a flowchart of local switch operations according to the present invention.
[0020] [0020]FIG. 8 illustrates an alternative embodiment of the present invention in a redundant fabric environment.
[0021] The figures depict a preferred embodiment of the present invention for purposes of illustration only One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein.
DETAILED DESCRIPTION OF EMBODIMENTS
[0022] A system and method for managing cluster membership and locks using a fabric in a Fibre Channel communications network is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the invention can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the invention.
[0023] Reference in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[0024] Some portions of the detailed description that follows are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps (instructions) leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical, magnetic or optical signals capable of being stored, transferred, combined, compared and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.
[0025] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussion, it is appreciated that throughout the description, discussions utilizing terms such as “processing” or “computing” or “calculating” or determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system memories or registers or other such information storage, transmission or display devices.
[0026] The present invention also relates to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, an magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, application specific integrated circuits (ASICs), or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus. Furthermore, the computers referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability.
[0027] The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may also be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will appear from the description below. In addition, the present invention is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the present invention as described herein, and any references below to specific languages are provided for disclosure of enablement and best mode of the present invention.
[0028] Reference will now be made in detail to several embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever practicable, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0029] Fibre Channel Network Structure
[0030] [0030]FIG. 1 illustrates a Fibre Channel network 100 with a zone 178 of hosts or nodes specified in an embodiment of the present invention. Generally, the network 100 is connected using Fibre Channel connections, though other network interconnects such as Infiniband or Myrinet could be used. In the embodiment shown and for illustrative purposes, the network 100 includes a fabric 102 comprised of four different cluster control switches 110 , 112 , 114 , and 116 . It will be understood by one of skill in the art that a Fibre Channel fabric may be comprised of one or more switches.
[0031] A variety of devices can be connected to the fabric 102 . A Fibre Channel fabric supports both point-to-point and loop device connections. A point-to-point connection is a direct connection between a device and the fabric. A loop connection is a single fabric connection that supports one or more devices in an “arbitrated loop” configuration, wherein signals travel around the loop through each of the loop devices. Hubs, bridges, and other configurations may be added to enhance the connections within are arbitrated loop.
[0032] On the fabric side, devices are coupled to the fabric via fabric ports. A fabric port (F_Port) supports a point-to-point fabric attachment. Typically, ports connecting one switch to another switch are referred to as expansion ports (E_Ports).
[0033] On the device side, each device coupled to a fabric constitutes a node. Each device includes a node port by which it is coupled to the fabric. A port on a device coupled in a point-to-point topology is a node port (N_Port). The label N_Port may be used to identify a device, such as a computer or a peripheral, which is coupled to the fabric.
[0034] In the embodiment shown in FIG. 1, fabric 102 includes switches 110 , 112 , 114 and 116 that are interconnected. Switch 110 is attached to hosts or nodes 156 and 158 . Switch 112 is attached to nodes 150 and 152 . Switch 114 is attached to storage device 170 . Typically, storage device 170 is a storage device such as a RAID device. Alternatively the storage device 170 could be a JBOD or just a bunch of disks device. Switch 116 is attached to storage devices 132 and 134 , and is also attached to node 160 . A user interface 142 also connects to the fabric 102 .
[0035] Overview of Zoning within the Fibre Channel Network
[0036] Zoning is a fabric management service that can be used to create logical subsets of devices within a Storage Area Network, and enables the partitioning of resources for the management and access control of frame traffic. More details on zoning and how to implement zoning are disclosed in commonly assigned U.S. patent application Ser. No. 09/426,567 entitled “Method and system for Creating and Formatting Zones Within a Fibre Channel System,” by David Banks, Kumar Malavalli, David Ramsay, and Teow Kah Sin, filed Oct. 22, 1999, and Ser. No. 10/123,996, entitled “Fibre Channel Zoning by Device Name in Hardware,” by Ding-Long Wu, David C. Banks and Jieming Zhu, filed Apr. 17, 2002, which are hereby incorporated by reference.
[0037] Still referring to FIG. 1, a zone 178 includes nodes 150 , 152 , 154 , 156 and 160 and storage device 170 . A zone indicates a group of source and destination devices allowed to communicate with each other. In this case zone 178 is the exemplary cluster. An exemplary use of this cluster would be execution of a large database.
[0038] [0038]FIG. 2 is a block diagram of a system 228 indicating an example of the connections used within a Fibre Channel fabric according to an embodiment of the present invention. In the example shown, system 228 includes two cluster control switches 240 and 230 , a device 260 and a device 250 Switch 240 includes a central processing unit (CPU) 246 for managing its switching and cluster functions, and switch 230 includes a CPU 236 for managing its switching and cluster functions. Switch 240 includes two ports 242 and 244 ; switch 230 includes two ports 232 and 234 . The number of ports shown on each switch is purely representative; and it will be evident to one of ordinary skill in the art that a switch may contain more or fewer ports. Device 260 is communicatively coupled via its node port 262 to port 242 on switch 240 . Device 250 is communicatively coupled via its node port 252 to port 234 on switch 230 . Switch 240 and switch 230 are interconnected via ports 244 and 232 .
[0039] [0039]FIG. 3 illustrates a basic block diagram of a cluster control switch 200 , such as switches 110 , 112 , 114 , 116 , 230 or 240 according to the preferred embodiment of the present invention. A processor and I/O interface complex 202 provides the processing capabilities of the switch 200 . The processor may be any of various suitable processors, including the Intel i960 and the Motorola or IBM PowerPC. The I/O interfaces may include low speed serial interfaces, such as RS-232, which use a driver/receiver circuit 204 , or high-speed serial network interfaces, such as Ethernet, which use a PHY circuit 206 to connect to a local area network (LAN). Main memory or DRAM 208 and flash or permanent memory 210 , are connected to the processor complex 202 to provide memory to control and be used by the processor.
[0040] The processor complex 202 also includes an I/O bus interface 212 , such as a PCI bus, to connect to Fibre Channel circuits 214 and 216 . The Fibre Channel circuits 214 , 216 in the preferred embodiment each contain eight Fibre Channel ports. Each port is connected to an external SERDES circuit 218 , which in turn is connected to a media interface 220 , which receives the particular Fibre Channel medium used to interconnect switches used to form a fabric or to connect to various devices.
[0041] [0041]FIG. 3A is a general block diagram of an exemplary node 270 . It is understood that this diagram is for illustration purposes and many other variations are suitable for the node. A processor 272 is connected to a memory controller/bridge chip 274 . DRAM or main memory 276 is connected to the chip 274 to provide the main program memory used by the node 270 . A PCI bus is connected to the chip 274 , with various devices connected to the PCI bus. A flash memory 278 provides permanent boot memory. A hard drive interface 282 is connected to a hard drive for local storage of the operating systems and programs. An Ethernet interface 280 provides a local area network connection. A host bus adaptor or HBA 286 provides the connection to the fabric. The HBA 286 includes a Fibre Channel circuit 288 , a SERDES 290 and a media interface 292 .
[0042] Proceeding then to FIG. 4, a general block diagram of the cluster control switch 110 , 1112 , 114 , 116 , 200 , 230 or 240 hardware and software is shown. Block 300 indicates the hardware as previously described. Block 302 A is the basic software architecture of a principal cluster control switch. Generally think of this as the principal switch operating system and all of the particular modules or drivers that are operating within that embodiment. One particular block is the cluster services 304 . The cluster services 304 has various blocks including a membership algorithm block 306 A, a lock manager block 308 A, a lock area 310 A, and an API block 316 to interface the cluster services to the operating system 302 and driver modules 318 to operate with the devices in the hardware 300 . Other modules operating on the operating system 302 are Fibre Channel, switch and diagnostic drivers 320 ; port modules 322 , if appropriate; a driver 324 to work with the Fibre channel circuits; and a system module 326 In addition, because this is a fully operational switch as well as a cluster control switch, the normal switch modules for switch management and switch operations are generally shown in the dotted line 320 . This module will not be explained in more detail.
[0043] A local cluster control switch 302 B is shown in FIG. 4B. The local switch 302 B is very similar to the principal switch 302 A, except that the local switch 302 B includes a local membership module 306 B, a local lock manager 308 B and a local lock area 310 B. As will be described in more detail below, the local versions of the modules only act as interfaces between the nodes and the principal switch 302 A, storing only local information, such as caching local copies of lock status for nodes connected to the local switch. The membership algorithm module 306 A performs the primary membership functions, while the lock manager module 308 A performs the primary or fabric-wide lock function, keeping the lock information in the lock area 310 A A given switch can preferably include both the local and principal modules, with the principal modules being active if the switches collectively select that switch to act as the principal switch.
[0044] Operation of a node according to the present invention is shown in FIG. 5. In a first step 500 the node registers with the cluster services in step 500 . This is done by sending an appropriate call using a cluster membership message addressed to the local switch to which it is connected. The cluster membership message is formed using the proper API to the local switch to which it is connected. Control then proceeds to step 502 where particular resources which need to be locked are also registered with the principal switch, preferably using common transport (CT) logic commands developed for lock management. This can be done using a lock message addressed to a well known address.. Control then proceeds to step 504 where the node sends a heartbeat message, a different cluster membership message, to indicate that it is properly operational and so needs to be considered operational as part of the cluster. Control proceeds to step 506 to determine if the node has received any messages from the switch. If so, control proceeds to step 508 where these messages are processed. These messages will generally relate to membership information, such as the status of other nodes connected to the cluster. If no messages are received in step 506 , or after execution of step 508 , control proceeds to step 510 to determine if the node needs a locked resource. If so, control proceeds to step 512 where a lock message is sent to the switch using the API to request control of the particular locked resource. If the resource is not needed in step 510 or control is requested in step 512 , control proceeds to step 514 to determine if the node desires to leave the cluster. If not, control loops back up to step 504 where another heartbeat message is sent to the switch. If it does desire to leave the cluster in step 514 , control proceeds to step 516 where the node unregisters with switch cluster services.
[0045] It is noted that while this is shown in FIG. 5 as a sequential or polled manner, in most cases these would be different threads which are operating inside the node so that they would actually be occurring simultaneously. For example, heartbeat messages would be sent periodically based on a timer routine, while received messages would be activated based on interrupt receipt of a particular message. Further, the need for locked resources would be occurring for a particular module which needed the particular resources. Thus this drawing of FIG. 5 is shown in a simplistic form to show the general operation of the node.
[0046] It is also noted that FIG. 5 does not show the various data messages, which are transferred between the nodes to transfer data between the nodes. These data messages are addressed to the appropriate node and are transferred through the switches forming the fabric as appropriate.
[0047] [0047]FIG. 6 illustrates principal switch operation for the cluster services according to the present invention. In step 600 the switch receives the various registration requests, a type of cluster membership message, forwarded from the local switches and provides a status message back to the local switch. Control then proceeds to step 602 , where the principal switch sets up the proper zoning to isolate and configure the proper cluster zones. This zoning information is provided to each of the local switches so the zoning hardware can be appropriately configured. This can be done as shown in above-referenced applications. Control then proceeds to step 604 to receive any resource lock allocations forwarded from the local switches. In this step the principal switch sets up the various lock areas requested by the nodes using a lock message and provides a status response back to the local switch Control then proceeds to step 606 to determine if a heartbeat message has been forwarded from a local switch. This would indicate that a particular node is still alive and should properly remain in the membership of the cluster. Control proceeds to step 608 if no message has been received to determine if a particular timeout for that particular node has passed. If not, control proceeds to step 610 , which is also where control would proceed after step 606 if a message had been received. In step 610 the switch determines if a disconnect request has been forwarded from a node because the node desires to unregister from the cluster. If not, control proceeds to step 612 to see if the node has been physically disconnected from the fabric, based on a message from a local switch. If the timeout has passed in step 608 , a disconnect request has been received in step 610 or the node has been physically disconnected in step 612 , control proceeds to step 614 where the principal switch removes the particular node from cluster membership according to the desired cluster membership algorithms. Numerous different membership algorithms could be utilized as desired. During this process the principal switch also alerts the local switches and the nodes using cluster membership messages so that each switch in the fabric and node in the cluster is aware of the particular cluster membership at any given time. Further, the principal switch also changes the zoning to indicate that the node has been removed, which zoning changes are sent to the local switches. Preferably this is done by changing the zoning so that the affected node only has read-only privileges and cannot write to any devices in the cluster, including the hosts and storage devices. Control proceeds from step 614 or if the node has not been disconnected in step 612 , to step 616 to determine if a lock request has been forwarded by a local switch. If so, control proceeds to step 618 where the particular lock request is processed by the lock management module to determine if the particular process or resource is locked. A reply is provided to the local switch of an acknowledgement or any rejection.. It is also noted that as in FIG. 5, the operations are shown in a polled or sequential manner for ease of explanation but in most cases the various requests or messages would be handled as received.
[0048] It is noted that transferring of the data messages between the nodes is not shown in FIG. 6. This is because those transfers would occur as basic hardware switching functions of the switches, and thus are not part of the cluster services illustrated in FIG. 6.
[0049] [0049]FIG. 7 illustrates local switch operation for the cluster services according to the present invention. In step 700 the local switch receives the various registration requests from the nodes. Control then proceeds to step 702 , where the registration request is forwarded to the principal switch, with the principal switch returning a status message and any changes in zoning. The status message is forwarded to the node. In step 704 the local switch sets up the proper zoning to isolate and configure the proper cluster zones. Control then proceeds to step 706 to receive any resource lock allocations from the nodes. In step 708 , the local switch forwards the lock allocations to the principal switch and sets up a local, cached copy in the local lock area 310 B. Also in step 708 the local switch receives a status message from the principal switch and forwards it to the node.
[0050] Control then proceeds to step 710 to receive any zoning changes received from the principal switch. As described above, the principal switch preferably handles the membership algorithm. Should the principal switch determine that a node needs to be removed, it will forward the appropriate zoning changes to all the local switches. For example, if a node has become non-responsive, the principal switch could tell each local switch to zone that node for read-only operation so that the node cannot corrupt the database. At a later time the node could receive full rights, but only after it satisfies membership requirements for the cluster. The received zoning changes are applied in step 712 .
[0051] Control then proceeds to step 714 to determine if a heartbeat message has been received. This would indicate that a particular node is still alive and should properly remain in the membership of the cluster. Control proceeds to step 718 if no message has been received to determine if a disconnect request has been received from a node because the node desires to unregister from the cluster. If not, control proceeds to step 720 to see if the node has been physically disconnected from the fabric. If a heartbeat message was received in step 714 , a disconnect request has been received in step 718 or the node has been physically disconnected in step 720 , control proceeds to step 716 where the local switch forwards the message or status change to the principal switch.
[0052] Control proceeds from step 716 , or if the node has not been disconnected in step 720 , to step 722 to determine if a lock request has been received. If so, control proceeds to step 724 where the particular lock request is forwarded by the local lock management module 308 B in the local switch to the principal switch and a response is received from the principal switch. The response is forwarded to the node on step 726 , with the state cached in the local lock area 310 B. Control then proceeds from steps 722 or 726 to step 700 . It is also noted that as in FIG. 6, the operations are shown in a polled or sequential manner for ease of explanation but in most cases the various requests or messages would be handled as received.
[0053] It is noted that transferring of the data messages between the nodes is not shown in FIG. 7. This is because those transfers would occur as basic hardware switching functions of the switches, and thus are not part of the cluster services illustrated in FIG. 7.
[0054] The above example of cluster membership and lock management has been done using a single fabric for ease of explanation. In many cases Fibre Channel fabrics are often duplicated between devices to provide redundancy. This is shown in illustrative form in FIG. 8. Network servers 800 and 804 and mainframe 804 are each connected to fabric (1) 808 and fabric (2) 806 . Disk arrays 810 and 812 are also each connected to fabric (1) 808 and fabric (2) 806 . Thus there are two paths between any device, providing the desired redundancy. However, this arrangement complicates cluster membership and lock operations. While it would be possible to run those operations independently in each fabric, it is desirable to insure that the two fabrics are synchronized. Therefore, an inter-fabric cluster controller 814 is preferably provided. The controller 814 is connected to fabric (1) 808 and fabric (2) 806 by links 818 and 820 , respectively. The actual control unit 816 is connected to these links. The block diagram of the control unit 816 is similar to the block diagram of switch 200 .
[0055] Preferably the controller 814 does not pass messages, either cluster membership, lock or data between the fabrics 808 and 806 , though it may perform normal data message switching functions for each fabric independently if desired. In the preferred embodiment the controller 814 acts as the principal switch for each fabric. The controller 814 has additional software modules to check for consistency between the cluster membership and lock status of each fabric. Should an inconsistency develop, the controller 814 will send appropriate messages to each fabric 808 and 806 to maintain the consistency.
[0056] [0056]FIG. 8 illustrates an additional problem which may occur As can be seen, each device has two Fibre channel ports. But locks and cluster membership are based on the node, or software instance executing on the node, not on each Fibre channel port. Thus the registration and allocation requests, and cluster membership and lock ownership, are preferably based on the node or process, not the Fibre Channel port. For this description, it is assumed that the various messages are provided appropriately and the various switches and controllers base operations at the appropriate level for the particular action.
[0057] An additional point which should be addressed is the failure of the local or principal switches. If a local switch fails, new locks associated with nodes connected to that local switch would not registered but previously existing locks would operate normally. If a principal switch fails, no new locks will be registered and a new principal switch will be elected from the local switches. Each local switch will provide its cached local lock information to the new principal switch to recreate the principal lock area. The principal switch will verify the lock ownership and normal operation will resume.
[0058] The cluster membership operation described above is the preferred embodiment. However, a more simplified version can be implemented according to the invention. In the simplified version the principal switch does not perform the membership algorithm but instead broadcasts messages to all of the cluster nodes if an event affecting cluster membership occurs, such as a missing heartbeat message or a link failure, with the nodes thus communicating among themselves directly to determine the proper response While this simple approach does not relieve the hosts from as much processing and message handling as the preferred embodiment, it is believed that there will still be a marked reduction because the membership affecting events will be very infrequent in normal operation.
[0059] In addition while the preferred embodiment performs the distributed operation by use of local switches and a principal switch, fully equal switches could be utilized, with each switch providing messages to update all other switches or by having switches responsible only for their local nodes and query the other switches for other operations, as in distributed name server operation. This equal switch organization would work satisfactorily in small fabrics, but operation would degrade for larger fabrics and for that reason the local and principal organization is preferred
[0060] Therefore it can be seen in the particular disclosed cluster control switch both the cluster management and the cluster lock activities. The operations and communications of the particular hosts or nodes in the cluster are offloaded, as is the complicated processing. Therefore performance of the nodes is increased, increasing overall cluster performance.
[0061] Although the invention has been described in considerable detail with reference to certain embodiments, other embodiments are possible. As will be understood by those of skill in the art, the invention may be embodied in other specific forms without departing from the essential characteristics thereof For example, different numbers of ports (other than the four ports illustrated herein) may be supported by the zone group based filtering logic. Additionally, the hardware structures within the switch may be modified to allow additional frame payload bytes to be read and used for frame filtering. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims and equivalents.
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Managing cluster membership and providing and managing locks in the switches forming the interconnecting network. To manage the cluster membership, a zone is created, with indicated members existing in the zone and the zone being managed by the switches. The nodes communicate their membership events, such as alive messages, using an API to work with the switch to which they are attached. The desired membership algorithm is executed by the switches, preferably in a distributed manner. Each switch then enforces the membership policies, including preventing operations from evicted nodes. This greatly simplifies the programs used on the nodes and unburdens them from many time consuming tasks, thus providing improved cluster performance. In a like manner, the switches in the fabric manage the resource locks. The nodes send their lock requests, such as creation and ownership requests, to the switch to which they are connected using an API. The switches then perform the desired lock operation and provide a response to the requesting node. Again, this greatly simplifies the programs used on the nodes and unburdens them from many time consuming activities, providing improved cluster performance.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present Application is based on International Application No. PCT/EP2006/062972 filed on Jun. 7, 2006, which in turn corresponds to French Application No. 05 06178 filed on Jun. 17, 2005, and priority is hereby claimed under 35 USC §119 based on these applications. Each of these applications are hereby incorporated by reference in their entirety into the present application.
FIELD OF THE INVENTION
The present invention relates to a method for antimissile protection of vehicles and a device for using this method.
BACKGROUND OF THE INVENTION
The invention relates to the protection of vehicles such as aircraft (airplanes, helicopters) or ground vehicles (trucks, tanks) from the threat of missiles using infrared, TV or electromagnetic guidance, and more generally, missiles fitted with a target-seeking device, or associated with such a device.
Portable missiles, fired by a single individual, are a significant threat, both from a military point of view and with respect to possible terrorist use. The well-known example of the firing of an IR missile at a jumbo jet during takeoff by a lone activist located in the vicinity of an airport illustrates this type of threat.
In order to combat this type of threat, current solutions are based on the principle of detection of the threat and dealing with it using appropriate countermeasures. The detection is carried out by stationary (ground-based) systems or systems carried on moving vehicles and consists of either radar detection or optical detection. This detection uses tracking methods to trigger such countermeasures as evasive actions, active or passive radar decoys, passive or active infrared decoys and lasers, antimissile weapons, etc.
The current solutions have the following disadvantages. The use of a method of detection then a countermeasure to the threat requires a very short response time compared with the minimum flight time of a missile, since missile flight times are short. This constraint results in a potentially high rate of false alarms. If the system is mounted on an aircraft or a vehicle, the cost and the weight of the system are major factors in the selection of the solution. Moreover, the integration of optronic countermeasure systems into fleets which are already operational can be achieved by the addition of a detachable “pod” which may alter the aerodynamic characteristics of the carrier, which affects the consumption.
The use of decoys, such as infrared jamming canisters, is not possible near civil airports, because of the fire risks inherent in such devices. The use of laser jammers requires a missile/target tracking system ensuring the beam is aimed into the field of view of the missile.
SUMMARY OF THE INVENTION
An aspect of the present invention is a method for antimissile protection of vehicles which has a very short response time with practically no false alarms and not requiring the use of means such as decoys of the type previously mentioned or conventional laser jammers, while providing the best possible protection.
Another aspect of the present invention is also a device for antimissile protection of vehicles which is as simple and light and economical as possible.
In one aspect of the invention, a method for antimissile protection of vehicles includes creating one curtain of plasma filaments between these vehicles and the probable launch point of these missiles, this curtain being intended to blind the target-seeking device of the missiles.
According to one advantageous feature of the invention, the plasma filaments are close together so as to produce an almost continuous ionized layer.
According to another advantageous feature of the invention, the plasma curtain is created by a laser beam sweeping a corresponding portion of space in a plane generally perpendicular to the probable trajectory of missiles on the approach to threatened vehicles.
The antimissile protection device according to the invention is characterized in that it comprises a pulsed laser, a device for controlling the spectral phase of the laser and a spatial sweep device for orienting the laser beam in various directions in space.
Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the invention. Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
Other characteristics and advantages of the invention will become apparent with the aid of the description which follows in conjunction with the appended drawings which represent:
FIG. 1 is a simplified diagram of an example of a device for using the method of the invention for protection of an airport, its upper portion being a top view, and its lower portion a side view;
FIG. 2 is a simplified diagram of another example of a device for using the method of the invention for protection of an airport, its upper portion being a top view, and its lower portion a side view;
FIG. 3 is a simplified example of a device for using the method of the invention for protection of an airplane in flight; and
FIG. 4 is a simplified example of a device for using the method of the invention for protection of a ground vehicle, its lower portion being a top view, and its upper portion a front view.
DETAILED DESCRIPTION OF THE INVENTION
In brief, the invention includes making a plasma curtain by using a laser placed in a particular area. The purpose of the protective screen formed by this curtain is to prevent the homing devices of missiles from locking on to the target. The invention uses the properties of ultrashort laser pulses (preferably with a duration of less than 10 ps) to create filaments of plasma by ionizing the air. In fact, a laser pulse which spreads through the atmosphere can be focused on a given point in space to create a plasma at this point. Along the extension of this point a filament is then produced in the propagation axis of the beam. This filament spreads over long distances (up to several kilometers) and has emissivity properties like those of a black body brought to high temperature (>1000 K up to 3000° K.). This filament typically has a diameter of a few hundred microns.
The laser used by the invention is a pulsed laser, having a pulse repetition frequency for example between 10 Hz and 10 kHz. The duration of the pulses of this laser is as brief as possible, for example less than 10 ps. In fact, the longer the duration of these pulses, the more energy the laser must supply. This energy is advantageously between 1 mJ and several joules, its value depending in particular on the duration of the pulses and the characteristics of the filaments that need to be produced. The laser wavelength value is not critical. Advantageously, commercially available lasers are used, for example solid-state media of the titanium-sapphire type which have a wide fluorescence spectrum in the vicinity of the 800 nm wavelength, which makes it possible to produce sub-picosecond (“femtosecond”) pulses using CPA (“Chirp Pulse Amplifier”) technology.
The protective screen is created as follows. The output beam of the pulsed laser is made to sweep in a plane, to create a curtain of filaments that need to be placed between the vehicle to be protected and the homing device or aiming system of a missile. Since the filaments emit in the spectral bands of the sensors with which the homing devices (or target-seeking devices) of missiles are usually provided, a blinding effect and masking of the line of fire occurs. The screen formed by this curtain of filaments can be used either to prevent launches by neutralizing the target acquisition, or to jam the missile in flight by masking the target with an effect similar to that of decoys.
The inventive device, hereinafter simply called a “jammer”, essentially comprises the laser such as described above, a device for controlling the spectral phase of this laser and a spatial sweep device for the beam of this laser.
The construction of a laser for creating a filament of ionized air, and the control of the spectral phase of its beam with a view to controlling the length of this filament being already known, will not be described in more detail. A device for controlling the spectral phase of a laser beam is known for example according to the French patent 2 751 095. It will however be noted that since the device for deflection of a laser beam is also already known, the present description relates more particularly to the combination of these various means to produce a screen of filaments and its use for the protection of vehicles.
Schematically illustrated in FIG. 1 is a first embodiment of the invention for the protection of an airport, in which the inventive device is used to create a screen below the planes of descent or ascent of aircraft. The effect of this is to block the line of fire of the homing device of any missile ready to be fired from the side or into the rear section of the aircraft. The device is placed at the end of the runway and aims upward at an angle slightly less than that of the trajectories followed by the aircraft. An azimuthal sweep creates the curtain of filaments. In this FIG. 1 , the upper portion is a top view of an example of a configuration of a device of the invention for protecting an airport, while the lower portion of this figure is a side view of this same configuration.
It is assumed, as would usually be the case, that a possible threat of terrorist attack is likely to occur near the takeoff and/or landing runway 1 of an airport, from the ground and generally in an area where the aircraft are at low or very low altitude. To protect these aircraft, there is placed on the axis of the runway 1 , along the extension of its end, near this end, a jammer 2 of which the laser beam, when the laser is operating, in the rest position 3 (not sweeping), is directed along the axis of this runway, away from the runway, and of which the angle of elevation is slightly less than the angle of the landing (or takeoff) trajectory 4 of aircraft 5 . When the protective device is operating, the laser beam is made to sweep in a plane, generally symmetrically in relation to the rest position 3 . The plane in which this sweep takes place is such that its intersection with the ground is perpendicular to the axis of the runway 1 . The angle of deflection of the laser beam to provide this sweep depends, in particular, on the distance between the jammer and the edge 6 of the curtain 7 of plasma filaments (edge formed by the points of creation of the filaments) and the lateral extension of the zone 8 where the protection needs to be provided. It will be noted that this protection zone is slightly more extensive longitudinally and laterally than the curtain of filaments because the blinding by a plasma filament of a missile target-seeking device is caused in a space which is wider than the diameter of this filament. The frequency of this sweep depends on the lifetime of the filaments (a few hundred microseconds to a few tens of microseconds, even a few hundred microseconds, depending on the ionization of the medium in which these filaments are created). It is for example a few kHz. Thus, the plasma screen 6 protects the aircraft when they are near the runway 1 (within missile range) against missiles fired from a launch point 9 located near the runway 1 , the line of fire coming from this launch point (and passing through a point marked by a cross 10 on the drawing) being able to be directed toward any point in the protected zone 8 .
Of course, to provide better airport protection, it is advantageous to use crisscross multiple jammers placed at the ends of takeoff runways and/or at various distances from these ends. A simplified example of an airport protection is illustrated in FIG. 2 . Schematically illustrated in this FIG. 2 are two runways 11 , 12 which intersect and which have different orientations. Jammers 13 to 16 are placed near the ends of the runways 11 and 12 respectively, according to an arrangement similar to that of the jammer 2 in FIG. 1 . These jammers 13 to 16 create protected zones 17 to 20 respectively, similar to the zone 8 in FIG. 1 . In the case of a heliport, the same method is used to protect the low altitude approach or departure corridors of helicopters.
It is also possible to use a method for moving the curtain of filaments which follows the trajectory of the vehicle to be protected. This tracking can be generated at the laser by controlling the focusing distance and/or by controlling the spectral phase of the pulses in order to pre-compensate for the effect of dispersion of the propagation medium, i.e. the atmosphere. Schematically illustrated in FIG. 3 is an example of using such a method at an airport similar to the one in FIG. 2 , and comprising the runways 11 and 12 . Illustrated is only one mobile protection zone for one jammer 14 A (similar to the jammer 14 , but able to produce a mobile protection zone). It is clearly understood that all the other jammers 13 A, 15 A and 16 A (similar to the jammers 13 , 15 and 16 respectively) can have the same characteristics as the jammer 14 A. Illustrated are various successive positions 21 to 24 of the protection zone created by the jammer 14 A, the movement of this protection zone being synchronized with the movements of the aircraft to be protected, advantageously so that the aircraft is generally near the center of the protection zone at all times.
Of course, as illustrated in FIG. 4 , the jammer of the invention can be used in the case of the protection of a convoy 25 of moving vehicles on the ground (cargo trucks, for example) against a ground-ground threat (a tank 26 , for example). In that case, the geometry of the plasma curtain 27 generated on board at least one of the vehicles (for example by the jammer 28 placed in the tail vehicle 29 ) is in the form of a vertical plane placed between the whole of the convoy 25 and the threat 26 .
According to another embodiment of the invention, the plasma of the filaments of the curtain of filaments is initiated by using a femtosecond pulsed laser of the type described above, and as soon as the initiation has taken place, instead of maintaining the ionization of these filaments by using the same femtosecond laser, it is maintained by using a power laser of the pulsed type (of a few watts to a few kilowatts, depending on the duration of its pulses), producing relatively long laser pulses (with a duration of several nanoseconds to several microseconds), of which the wavelength is not very critical (it can be located in the infrared, the visible or the ultraviolet).
An advantageous application of the method of the invention consists in generating remotely a virtual object moving in space, this object being either a plasma curtain or a plasma filament. This virtual object can have the dimensions and the form of normal ground or air vehicles, and its movements can, due to its intense brightness, either simulate the trajectory of a vehicle in space, or act as decoys capable of attracting optronic homing sensors. Thus, the protection of real vehicles described above can be replaced or supplemented, by attracting the missiles toward these virtual objects.
The main advantages of the method of the invention and the device for using it are that it does not use a missile detector, and is therefore not limited by a rapid response loop, it helps to mislead optronic homing device missiles and it does not produce any chemical, mechanical or more generally material residues.
It will be readily seen by one of ordinary skill in the art that the present invention fulfills all of the objects set forth above. After reading the foregoing specification, one of ordinary skill will be able to affect various changes, substitutions of equivalents and various other aspects of the invention as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by the definition contained in the appended claims and equivalents thereof.
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The present invention relates to a method for antimissile protection of vehicles having a very short response time with practically no false alarms and not requiring the use of means such as decoys or conventional laser jammers, while providing the best possible protection. It is characterized in that at least one curtain of plasma filaments is created between these vehicles and the probable launch point of these missiles, this curtain being intended to blind the target-seeking device of the missiles.
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The present invention is concerned generally with a hydraulic cement useful for manufacturing cement based products and concrete structures. More particularly the invention is concerned with a hydraulic cement containing an activated alpha belite phase for providing enhanced structural strength in cement-based products.
Conventionally, the most common hydraulic cement, portland cement, is manufactured by heating to about 1450° C. a mixture of limestone and clay materials. This heating step causes partial fusion of the materials to form clinker nodules. These clinker nodules are then mixed with gypsum (about 5 wt. %) and ground to make a conventional portland cement. Such clinker nodules have a composition of approximately 67 wt. % CaO, 22 wt. % SiO 2 , 5 wt. % Al 2 O 3 and 3 wt. % Fe 2 O 3 with the residual being oxides of alkali and other metals. Such portland cement clinker nodules typically have four major phase components: alite, belite, an aluminate phase and an iron-based phase. The alite phase in conventional portland cement is the most important phase since it provides the greatest strength potential to the end product cement. Alite is tricalcium silicate modified by foreign ion incorporation, such as ions of Mg, Al and Fe. Since the alite phase contains the largest amount of lime relative to the other phases, it requires the most amount of heat input to manufacture.
The belite phase in conventional portland cement is the second most important phase in portland cement clinkers. This phase accounts for about 15 to 30 wt. % of the phase composition and is based on a dicalcium silicate ("C 2 S" where C is CaO and S is SiO 2 ) modified by taking up selected foreign ions. The normal stable form of belite is the beta polymorph with five polymorphs being formable at atmospheric pressure: alpha, alpha prime low, alpha prime high, beta and gamma. The beta polymorph of belite is characteristically slow to react with water and does not contribute much to cement strength potential during about the first seven days of curing; however, at later stages of curing, beta belite is the major strength producing phase. Beta belite has the further attribute that it takes less energy to produce than the alite phase by virtue of its lower lime content.
In the conventional manufacture of concrete structures, it is, of course, important to have early strength to sustain the basic structure. Therefore, while it is known that belite based cements can be relatively easy to make, beta belites made in the conventional manner do not have adequate early strength for commercial applications. In addition, when calcium silicates are mixed with water, hydration reactions result in forming cement gel, calcium hydroxide solution and calcium hydroxide crystallites. The cement gel is generally responsible for the strength of the cementitious system, but calcium hydroxide crystals have very little strength value and are believed to be sites of potential failure initiation. Consequently, efforts have been ongoing for a number of years directed to developing a portland cement clinker with reduced calcium hydroxide phase and containing a reactive belite with properties akin to the alite phase. In one approach, the belite phase was stabilized with addition of particular weight percents of Na/Al; K/Al; Na/Fe and K/Fe. In the Na/Fe and K/Fe systems, alpha and beta belite were crystallized as a single phase but alpha prime phases accompanied the alpha phase. For the other additive combinations, only alpha prime and beta phases were obtained. Various other efforts determined specific additive combinations and clinker cooling rates to stabilize belite phases. However, such efforts generally result in formation of substantial amounts of unwanted calcium hydroxide, and these methods are unable to form the alpha belite phase without the presence of contaminating undesirable belite phases.
It is therefore an object of the invention to provide an improved composition and method of manufacture of portland cement clinker.
It is another object of the invention to provide a novel compositional range for manufacture of an alpha belite cement clinker.
It is yet a further object of the invention to provide an improved composition of cement including a mixture of Na, K and Fe as additives to dicalcium silicate to make an alpha belite cement clinker.
It is also an object of the invention to provide a novel composition and method of making a portland cement having as hydration products a cement gel of relatively low calcium to silicon ratio and reduced calcium hydroxide crystalline content.
It is still another object of the invention to provide an improved portland cement of low permeability after hydration.
It is an additional object of the invention to provide a novel composition and method of manufacture of portland cement clinker producible at lower temperatures and with diminished energy input.
It is yet another object of the invention to provide an improved composition and method of manufacture of a portland cement having high strength and enhanced chemical stability to attack by sulfates, chlorides and selected aqueous solutions.
It is still a further object of the invention to provide a novel article of concrete manufacture and use thereof including a portland cement component primarily containing alpha belite and ferrite phases.
It is yet another object of the invention to provide an improved article of manufacture having improved grindability by virtue of having discontinuous belite particles with a ferrite coating.
It is also an additional object of the invention to provide an improved composition and method of manufacture of cement products using an alpha belite based portland cement clinker ground with (a) small amounts of gypsum or other forms of calcium sulfate and (b) a water reducing agent and/or a form of calcium sulfate or grinding or interblending any of the foregoing with pozzolanic material, such as fly ash, rice hull ash, blast furnace slag, silica fume, activated clays or like conventional materials.
Other advantages and objects of the invention will be apparent from the detailed description and drawings described hereinbelow.
BRIEF DESCRIPTION OF THE DRAWING
The FIGURE illustrates a pseudo-ternary phase diagram of various cement clinker materials with variable compositions of K 2 O, Na 2 O and Fe 2 O 3 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In a preferred form of the invention a hydraulic cement clinker can be prepared for use in cement products, such as hydraulic cement based structures. The clinker most preferably includes an active alpha belite phase but can also include a ferrite phase. Virtually no alite or aluminate phases are present in the clinker. It has been determined that a range of combinations of Na, K and Fe content enable stabilization of the alpha belite phase. In the most preferred embodiment the ratio of CaO to SiO 2 on an ignited basis is approximately two. A small amount of MgO can also be added to decrease the viscosity of the liquid phase created during the step of heating to form the clinker. Temperatures for producing the clinker preferably range from 1350° C. to 1400° C., but the clinker can also be formed using temperatures ranging from roughly 1250° C. to 1450° C. The preferred range of composition includes selected amounts of Ca, Si, K, Na and Fe; and the most preferred ranges and compositions are illustrated in Table I below:
TABLE I______________________________________(Weight percent compositions)Oxide Range Most Preferred______________________________________CaO 59-62 60SiO.sub.2 29-32 30Fe.sub.2 O.sub.3 3-5 4Na.sub.2 O 1-4 1.4K.sub.2 O 1-4 2.2MgO 0.25-2 0.5______________________________________
In the pseudo ternary phase diagram of the FIGURE, experimental examples of clinkers are shown in terms of the phase regions of alpha, beta, alpha (predominately) plus beta and beta (predominately) plus alpha. The ternary variables are mole percent K, Na and Fe with the moles of Ca and Si being substantially fixed as noted in Table IIA which lists the experimental samples prepared in the manner explained in the Examples. Table IIB shows the raw mixture preparation which produced the molar fractions of Table IIA. The raw mix preparations are also listed and described in the Examples.
TABLE IIA__________________________________________________________________________Example Compositions & PhasesSpecimen No. Phase(s) Moles Ca Moles Si Moles K Moles Na Moles Fe Moles O__________________________________________________________________________ 1 α 1.88247 0.89181 0.05794 0.05722 0.18422 4 2 α 1.88659 0.89377 0.04936 0.04852 0.18462 4 3 α 1.88832 0.89459 0.04649 0.04415 0.18479 4 4 α 1.88487 0.89295 0.05221 0.05288 0.18445 4 5 α 1.96995 0.93326 0.06063 0.05988 0.06885 4 6 α 1.95127 0.92441 0.05405 0.07299 0.09093 4 7 α 1.94299 0.92048 0.05382 0.07268 0.10186 4 9 α 1.95127 0.92441 0.05405 0.07299 0.09093 410 α 1.95239 0.92494 0.04049 0.08202 0.09098 410m α* + β 1.96352 0.93021 0.04532 0.07345 0.07777 411 β 1.96341 0.93016 0.00000 0.07804 0.09149 411m α* + β 1.95444 0.92591 0.00000 0.11424 0.09108 412 β 1.96004 0.92856 0.00000 0.09165 0.09134 414 α* + β 1.94666 0.92222 0.00000 0.14564 0.09071 415 α* + β 1.94445 0.92118 0.00000 0.15457 0.09061 415m α 1.94184 0.91994 0.03107 0.13402 0.09049 416 β* + α 1.94712 0.92244 0.02996 0.11381 0.09074 417 β* + α 1.94348 0.92072 0.04486 0.11360 0.09057 418 α 1.94905 0.92336 0.05399 0.08202 0.09083 433 α 1.95056 0.92407 0.06604 0.06385 0.09090 4FI-50 α 1.94761 0.92268 0.06893 0.07286 0.09076 4__________________________________________________________________________ *predominant phase
TABLE IIB__________________________________________________________________________Raw Mix Preparations Reagent Tamm's Reagent Hematite, Reagent Reagent ReagentSpecimen No. CaCO.sub.3 Quartz, SiO.sub.2 Fe.sub.2 O.sub.3 MgCO.sub.3 K.sub.2 CO.sub.3 Na.sub.2 CO.sub.3__________________________________________________________________________ 1 105.7 g 28.5 g 8.4 g 1.1 g 3.0 g 2.2 g 2 106.7 g 28.5 g 8.4 g 1.1 g 2.5 g 1.9 g 3 106.9 g 28.5 g 8.4 g 1.1 g 2.3 g 1.7 g 4 106.5 g 28.4 g 8.4 g 1.1 g 2.6 g 2.1 g 5 109.5 g 31.7 g 3.0 g 1.2 g 2.9 g 2.2 g 6 110.5 g 30.1 g 4.0 g 1.2 g 2.6 g 2.7 g 7 108.4 g 30.8 g 4.5 g 1.2 g 2.6 g 2.7 g 9 108.2 g 31.5 g 4.0 g 1.0 g 2.6 g 2.7 g10 108.0 g 31.3 g 4.0 g 1.0 g 2.6 g 3.2 g10m 109.3 g 31.9 g 3.4 g 0.9 g 2.2 g 2.7 g11 110.3 g 32.0 g 4.0 g 1.0 g -- 2.9 g11m 109.4 g 31.7 g 4.0 g 1.0 g -- 4.2 g12 109.9 g 31.9 g 4.0 g 1.0 g -- 3.4 g14 108.5 g 31.5 g 4.0 g 1.0 g -- 5.5 g15 108.0 g 31.6 g 4.0 g 1.0 g -- 5.8 g15m 108.0 g 31.5 g 4.0 g 1.0 g 1.9 g 4.8 g16 106.9 g 32.2 g 4.0 g 1.0 g 1.5 g 4.3 g17 106.4 g 31.9 g 4.0 g 1.0 g 2.2 g 4.3 g18 108.3 g 31.6 g 4.0 g 1.0 g 2.6 g 3.1 g__________________________________________________________________________
For each preparation in Table IIB the components were intimately mixed, then the resulting mixture was pelletized and reacted at 1400° C.
In Table IIC are illustrated prior art compositions for cements which produce various belite phases. These compositional examples of prior art are also plotted in the FIGURE for comparison purposes.
TABLE IIC__________________________________________________________________________Prior Art Compositions and Phases Phases Heating temper-R Ca Na Si Fe Al O formed ature (°C.)__________________________________________________________________________0.0 .40099 0.03286 .12044 0.079823 0.0 .36589 α 1520 α 1440 α 13600.0 .4075 0.0334 .1387 0.04867 0.0 .3718 α, α' 1520 α, α' 14400.0 .4299 0.0200 .14659 0.03238 0.0 .3711 β 1520 β 14400.0546 .39203 0.00 .11775 0.0780 0.0 .35771 α 1520 α 1440 α 13600.0555 .39821 0.00 .13555 0.04682 0.0 .36335 α, α' 1520 α, α' 14400.03354 .42400 0.0 .14456 0.03194 0.0 .36597 β 1520 β 14400.0 .41825 0.03427 .12563 0 0.04022 .38163 α', β 1520 α', β 14400.0 .43740 0.0203 .14085 0 0.02382 .37754 β 1520 β 14400.05691 .40844 0.0 .12268 0 0.03928 .37268 α', β 1520 α', β 14400.03411 .43125 0.0 .13187 0 0.02354 .37223 β 1520 β 1440__________________________________________________________________________
As can be noted from the tables and the phase diagram, there are well-defined regions of stability, and associated compositions, for the alpha belite phase. These preferred compositions can thus be produced in clinker form and be used to produce a cement product, such as a hydraulic cement, or other mixture which can take advantage of the excellent properties manifested by the alpha belite phase of the clinker. For example, the clinker can be processed by fine grinding of the clinker alone, fine grinding of the clinker with a small amount of gypsum or other conventional forms of calcium sulfate, fine grinding of the clinker with a water reducing agent and/or a form of calcium sulfate, or fine grinding or interblending any of the foregoing with a pozzolanic material, such as fly ash, rice huh ash, quenched blast furnace slag, silica fume, activated clays or like materials.
The above-described preferred ranges of composition are particularly useful in cement-based products wherein processing can include curing at slightly elevated temperatures, such as about 50° C. or higher. Curing of the product can also be done at room temperature, but the kinetics of curing result in a much slower gain of strength as noted in Table III below. The ultimate strength levels (substantially steady values) are substantially superior to cements having beta belite and/or alite phases also present with alpha belite with such mixed phase cements having compressive strengths of only 10-15,000 psi.
TABLE III______________________________________Paste Compressive Strength of αC.sub.2 S cement, psiComposition (wt. %)4.0%Fe.sub.2 O.sub.31.4%Na.sub.2 O 4.0% Fe.sub.2 O.sub.3 4.0% Fe.sub.2 O.sub.3 *4.0% Fe.sub.2 O.sub.32.2% 1.8% Na.sub.2 O 3.4% Na.sub.2 O 1.2% Na.sub.2 OK.sub.2 O 1.8% K.sub.2 O 1.3% K.sub.2 O 1.8% K.sub.2 O______________________________________1 Day 8000 200 3500 3200 (50° C.) (50° C.) (50° C.) (50° C.) 300 (Room Temp)7 Days 20,200 16,600 -- 30,300 (Room (Room (50° C.) Temp) Temp) 18,600 (Room Temp)28 25,200 25,200 -- 35,000Days (Room (Room (50° C.) Temp) Temp) 23,000 (Room Temp)______________________________________ *5% CaSO.sub.4 was added
When the clinker material is used with one of the pozzolanic materials, the amount of calcium hydroxide in the hardened paste is negligible. This paste also has less than 0.04 moles of calcium hydroxide and aluminate phases. As a consequence of minimizing the calcium hydroxide content, the tensile strength of the hardened paste is about 20% higher than conventional construction grade portland cement. The absence of the calcium hydroxide crystallites also allows the cement to be utilized with various types of fibrous material for reinforcement members. Furthermore, due to the very low percentages of aluminate phases, chemical stability is enhanced which results Ln minimizing vulnerability to sulfate attack. In addition, the tendency of the cement product to undergo rapid stiffening is also diminished.
In the most preferred embodiment the alpha belite phase is a discontinuous phase of grains covered with a thin coating of ferrite. For example, in a typical article of manufacture, the median (fifty percentile) size of belite gains is 32.5 microns with the sixteen to eighty-fourth percentile being from 15 to 62.5 microns diameter. The average distance between alpha belite C 2 S grains is 3.75 microns with a standard deviation of 2.6 microns. That is, the ferrite phase is about 3.75 microns thick and forms the substantially continuous ferrite matrix. Therefore, the clinker is much more grindable than a microstructure having a continuous matrix of belite which is highly abrasive and difficult to grind. On the other hand, the ferrite phase exhibits much better grinding characteristics, thereby enabling grinding of the clinker without having to reduce a continuous alpha belite phase.
Typical expected uses of an alpha belite based cement would include bridge decks, highway paving, hydraulic works, concrete pipes, macro defect free cement based products and fiber reinforced cement and concrete products.
The following nonlimiting example illustrate various aspects of the invention.
EXAMPLE I
Clinker and cement preparation were carded out by the following procedure: Batches of new mix weighing 1.6 kg were used as a starting material and had the following composition:
______________________________________limestone* 70.6%rice hull ash 22.0% 85% SiO.sub.2Fe.sub.2 O.sub.3 2.4% Baker Lot #505331, >99% purityNa.sub.2 CO.sub.3 2.5% Fischer Chemical Lot #886795, >99% purityK.sub.2 CO.sub.3 2.5% Sargent-Welch, CAS #584-08-7, technical grade 100.0%______________________________________ *CaO 53.88; SiO.sub.2 - 0.43%; MgO 0.62%, SO.sub.3 - 0.15; L.O.I. 43.75%
These constituents were freely ground (-200 mesh) in a large pebble mill and then pressed into 2-in. cylindrical pellets. Next, the pellets were placed in Pt dishes and burned, four pellets at a time, in an electric furnace at 1400° C. for 1 hour. XRD (X-ray diffraction) analysis showed the clinker produced to be mainly α-C 2 S (active component) with small amounts of free lime. Some small amounts of the latter appear useful for enhancing the hydraulic activity of α-C 2 S. Results of XRF (X-ray fluorescence) analysis conducted on the clinker (Formulation 1 or "F1") are shown in Table IV.
TABLE IV______________________________________CHEMICAL ANALYSIS Analyte Weight %______________________________________ SiO.sub.2 30.26 Al.sub.2 O.sub.3 0.49 Fe.sub.2 O.sub.3 4.07 CaO 59.49 MgO 0.88 SO.sub.3 0.17 Na.sub.2 O 2.05 K.sub.2 O 2.51 TiO.sub.2 0.04 P.sub.2 O.sub.5 0.38 Mn.sub.2 O.sub.3 0.10 SrO 0.02 LOl 0.21 Total 100.66______________________________________
Potential for Forming Compounds Calculated per ASTM C 150-89
______________________________________ C3S -4 C2S 90 C3A -4 C4AF 12______________________________________
From the clinker produced, two test cements, each weighing 4 kg, were prepared by grinding in a 1 cu ft steel ball mill for 11/2 hours. Their compositions are given as follows:
______________________________________F1RH F1GS______________________________________clinker 77.0% clinker 64.2%anhydrite 7.0% anhydrite (CaSO.sub.4) 5.8%(CaSO.sub.4) granulated slag 30.0%rice hull ash 16.0% 100.0% 100.0%______________________________________
Both cements have a Blaine (ASTM C 204) fineness of approximately 5000 cm 2 /g.
EXAMPLE II
Physical testing results on the two test cements of Example I were performed to determine compressive strength (ASTM C 109), sulfate expansion (ASTM C 1012), alkali aggregate reactivity (ASTM C 227), available alkalies (ASTM C 311), and drying shrinkage. For comparison, two ordinary portland cements meeting ASTM C 150 Type I requirements of low alkali (CC-2) and high alkali (CC-1) contents were tested along with the Formulation-1 cements. Due to the high level of mineral additive used in the two test cements, mixing water used in preparing their mortar for compressive strength by ASTM C 109 test was reduced to w/c=0.41. Consolidation of mortar into the 2-in. cube molds was done with the aid of a vibrating table; a similar procedure was also applied to the Type I cement mortar.
Drying shrinkage determination was performed on a 6×15×80 mm thin slab cement paste specimens moist cured for either 7 days or 28 days. Pastes were prepared by mixing cement and water in a Hamilton Beach mixer for a total mixing time of 2 minutes and cast into a specially designed mold to produce the specimens. The w/c ratio used for the Type I cement and the test cements were 0.50 and 0.42, respectively. The cured specimens were then dried over a supersaturated solution of Mg(NO 3 ) 2 (50% RH) in an enclosed jar.
EXAMPLE III
Table V shown below gives the mortar strengths of cement blends made from Formulation-1.
TABLE V______________________________________ASTM C 109 - Compressive Strength of Mortar Cubes Compressive Strength, psiCement 3 days 7 days 28 days 3 mo. 1 yr.______________________________________CC-2 (low-alkali 3310 5070 6060 7880 7683Type I)F1RH 1550 5090 7970 9380 9880F1GS 2530 5040 6910 8310 9620______________________________________
The results clearly indicate that they develop strength slower than portland cement, but starting at about 7 days their strengths are comparable. By 28 days the strength has surpassed that of portland cement by as much as 31 percent. Higher strengths are observed after 3 months time lapse. Moreover, at 1 year, the portland cement strength dropped slightly while the examples continued to increase.
Formulation-1 is essentially α-C 2 S, and upon hydration it would be expected to produce higher amounts of C-S-H by vol) compared to portland cement at equal degrees of hydration. In addition, the mineral additives used in the preparation of the two cements contain highly reactive silica such that any Ca(OH) 2 being formed during the hydration of α-C 2 S will ultimately form more C-S-H. This may be the source of their higher strengths.
The results of the sulfate expansion test by ASTM C 1012 (see Table VI) show higher expansion up to 12 weeks of exposure for the Formulation-1 blends. This expansion of about 0.10% remained virtually unchanged starting after about two weeks of exposure, indicating some degree of stability.
______________________________________AGE F1RH F1GS CC-2Weeks Length Length Length______________________________________1 0.079 0.079 0.0192 0.084 0.102 0.0233 0.085 0.104 0.0254 0.084 0.104 0.0265 0.086 0.103 0.0246 0.087 0.108 0.0297 0.091 0.125 0.0368 0.091 0.126 0.0369 0.090 0.125 0.03510 0.091 .0.127 0.03611 0.090 0.126 0.03612 0.089 0.127 0.037______________________________________
Table VII gives the results of the alkali-reactivity test by the ASTM C 227 test. It is apparent from the expansion data that Formulation-1 cement is not as useful on low alkali ordinary portland cement in conditions where reactive aggregates are involved. The degree of expansion shown by Formulation-1 cement is very similar to that of high alkali portland cement.
TABLE VII______________________________________Alkali-Aggregate ReactivityF1RH F1GS CC-1 CC-2Age Expansion Expansion High Alkali - I Low Alkali - IDays % % Expansion % Expansion %______________________________________14 0.015 0.119 0.073 -0.00128 0.026 0.151 0.105 0.00556 0.437 0.305 0.269 0.01090 0.594 0.355 0.321 0.012______________________________________
TABLE VIII______________________________________REPORT OF CHEMICAL ANALYSIS______________________________________56 day results Available Alkalies (wt. % of cement Sample paste) Equiv. %Specimen No. Description Na.sub.2 O K.sub.2 O Na.sub.2 O % SO.sub.3______________________________________CC-1 Cement paste 0.19 0.84 0.74 .008(High-AlkaliType I)CC-2 Cement paste 0.09 0.07 0.14 .011(Low-AlkaliType I)F1GS Cement paste 0.79 0.92 1.39 .148F1RH Cemcnt paste 0.97 1.26 1.80 1.00290 day results Available Alkalies (wt. % ofSpecimen Sample cement paste) Equiv. %No. Description Na.sub.2 O K.sub.2 O Na.sub.2 O______________________________________CC-1 Cement paste 0.18 0.80 0.70CC-2 Cement paste 0.07 0.06 0.11FIGS Cement paste 0.80 0.89 1.39F1RH Cement paste 0.92 1.19 1.70______________________________________
Test results for available alkalies shown in Table VIII are consistent with the ASTM C 227 data if one considers that the alkalies released during cement hydration cause the alkali-silica expansion problem. It is evident that most of the alkalies used as stabilizing additives to obtain the α-C 2 S phase are ultimately released during hydration; the rest of the alkalies appear to be incorporated in the C-S-H.
The drying shrinkage of pastes made from Formulation-1 cements are considerably higher than that of portland cement paste (see Table IX). Longer curing periods prior to drying favor the former, i.,e., lower shrinkage for longer cured pastes.
TABLE IX__________________________________________________________________________Drying Shrinkage Test Results% Drying Shrinkage (3-slab average)3d drying 7d drying 14d drying 28d drying7d cure 28d cure 7d cure 28d cure 7d cure 28d cure 7d cure 28d cure__________________________________________________________________________CC-2 0.26 0.27 (4d) 0.28 -- 0.30 0.31 (16d) 0.32 0.32(Type Icement)F1RH 0.64 0.44 (4d) 0.77 -- 0.85 0.66 (16d) 0.90 0.70F1GS 0.37 0.34 (4d) 0.47 -- 0.53 0.51 (16d) 0.60 0.55__________________________________________________________________________
The test results show that α-C 2 S can produce cement of excellent strength property. This high strength can be achieved with only an active α-C 2 S clinker component ranging from about 64-77 percent by weight of the cement with calcium sulfate and mineral additive making up the rest. The clinker can be produced from similar raw materials used for portland cement clinker production and at slightly lower clinkering temperature, making it commercially viable. There are apparent limitations to the use this cement. For instance, the high alkali release during hydration might prohibit its use in cases where reactive aggregates may be present. In case of higher sulfate expansion and drying shrinkage, these properties can be improved by further refining the cement composition and optimizing the sulfate content.
While preferred embodiments of the invention have been shown and described, it will be clear to those skilled in the art that various changes and modifications can be made without departing from the invention in its broader aspects as set forth in the claims provided hereinafter.
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An article of manufacture and method of manufacture of a cement product composition. A cementitious clinker consisting essentially of an alpha belite and a ferrite phase having a composition of about 0.04-0.13 moles Na 2 O, 0.03-0.07 moles K 2 O, 0.09-0.18 moles Fe 2 O 3 , and 2.8 moles dicalcium silicate.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to and claims the benefit of U.S. Provisional Patent Application Ser. No. 61/142,768, filed Jan. 6, 2009, U.S. Pat. No. 5,956,372, U.S. Pat. No. 6,075,817 and U.S. Pat. No. 7,336,747, all of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to method and apparatus for increasing the channel capacity of a bandwidth limited communications path, including the Telephone Twisted Pair (TTP) cable, optic fiber pipelines, microwave communication systems, mobile and personal communication networks and satellite communication networks.
BACKGROUND OF THE INVENTION
[0003] Immediate and high speed access to the vast amount of digital information available today is in critical demand for home entertainment, business communications and wireless communication devices.
[0004] One example of this demand, and the resources being applied to fulfill it, is the “triple play” effort being put forth by cable and telephone companies to supply high-speed internet access, television programming and telephone service over a single broadband connection.
[0005] For the telephone companies, the triple play is delivered to a resident or a business using a combination of optical fiber and Asynchronous Digital Subscriber Line (ADSL) technology. This configuration uses optical fiber to reach areas at long distances from the telephone central office, and uses ADSL or VDSL (Very-High-Data-Rate Digital Subscriber Line) over an existing TTP as the last mile to the home or business. This two step approach is necessary as DSL technology suffers from significant degradation in bandwidth over long distances.
[0006] It has been estimated that the bandwidth required to provide advanced triple-play services will require a downstream (head end or central office to residence or business) data rate of between 37 and 57 Mbits/sec. This is based on an average of 3 HDTV sets per household requiring 9-12 Mbits/sec each, high speed internet at 10-20 Mbits/sec, and IP voice at 0.25 Mbits/sec.
[0007] There are a number of basic DSL services for possible use with a triple play service; including ADSL, ADSL2+ and VDSL. ADSL can provide a downstream bandwidth of approximately 2 Mbits/sec at a distance of 18,000 feet, and 6 Mbits/sec at a distance of 6000 feet. ADSL 2+ can provide an approximate bandwidth of 25 Mbits/sec at 3000 feet using a second twisted pair. VDSL can provide an approximate bandwidth of 25 Mbits/sec at 3000 feet and the possibility of 57 Mbits/sec at 1000 feet using a second twisted pair. Therefore in order for a telephone company to provide a full service triple play configuration with existing DSL technology, it is necessary to install fiber optic networks which are accessible within approximately 1000 feet of every home or business.
[0008] Cable television operators face a similar problem as the majority of their current installations are Coaxial cable which cannot support the required bandwidth over long distances. Therefore they must also install fiber optic networks and use available coaxial cable, rather than a TTP for the last transmission mile. For cable companies the Hybrid Fiber Coaxiel (HFC) architecture is used for television programming and high-speed Internet access, while Voice over IP (VOIP) is used to deliver telephone service.
[0009] It is estimated that U.S. phone companies alone will have to spend more than $26 Billion to install the fiber optic networks needed for triple play service.
[0010] For wireless communications, advances in CDMA and GSM standards are also providing another medium to deliver video, Internet access and voice telephone service. Thus the triple play is becoming the “quadruple play” which means greater demand for available bandwidth. This demand is shown by the recent 700 MHZ auction in the U.S. which yielded $19 Billion in bids while telephone companies in the U.S. have bid $71 Billion for spectrum since 1995.
[0011] The goal of the present invention, to increase the information carrying capacity for any type of communications highway, requires an understanding of the basic theory underlying channel capacity as developed by Claude Shannon and Ralph Hartley. The Shannon-Hartley Theorem is an application of the noisy channel coding Theorem to the archetypal case of a continuous-time analog communications channel subject to Gaussian noise. The theorem establishes channel capacity, a bound on the maximum amount of error-free digital data (pulse based information) that can be transmitted over a communication link, with a specified bandwidth and in the presence of the noise interference. The theorem is based on the assumption that the signal power is bounded and the Gaussian noise process is characterized by a known power or power spectral density. To achieve this goal, conventional methods attempt to increase the number of bits per single modulating frequency using efficient technology enhancements. The improvement is limited since noise on the channel remains the same. The present invention sends multiple frequencies, each on its own virtual channel, with minimal increase in total physical channel bandwidth and ensures that each modulated frequency achieves maximum capacity within the constraints of the Shannon limit. The combined information throughput is the sum of capacities for all virtual channels. In essence the proposed invention provides a methodology for combining many virtual channels within the same constrained channel bandwidth that no other known systems can achieve.
[0012] Considering all possible multi-level and multi-phase encoding techniques, the Shannon-Hartley theorem states that the channel capacity C, meaning the theoretical upper bound on the rate of clean (error free) data that can be sent with a given average signal power S through an analog communication channel subject to additive white Gaussian noise of power N is given by;
[0000] C =Blog 2 (1 +S/N )
[0013] where:
C is the channel capacity in bits per second, B is the bandwidth of the channel in hertz, S is the total signal power over the bandwidth, measured in watts, N is the total noise power over the bandwidth, measured in watts, and S/N is the signal-to-noise ratio (SNR) of the communication signal to the Gaussian noise interference, expressed as a straight power ratio.
[0018] The Shannon-Hartley Theorem establishes what the channel capacity is for a finite-bandwidth continuous-time channel subject to Gaussian noise. It also makes it clear that bandwidth limitations alone do not impose a cap on maximum information rate. That is because it is possible for a digital pulse signal to take on an indefinitely large number of different voltage levels on each symbol pulse, with each slightly different level being assigned a different meaning or bit sequence. However, when noise and bandwidth limitations are combined, the Shannon-Hartley Theorem taught that there was a finite limit to the amount of information that could be transferred by a signal of a bounded power even when various multi-level encoding techniques are used.
[0019] The finite limit on channel capacity postulated by the Shannon-Hartley Theorem is based in part on the fact that in the channel considered by this theorem, noise and signal are combined by addition. That is, the receiver receives a signal that is equal to the sum of the signal encoding the desired information and a continuous random variable that represents the noise. This addition creates uncertainty as to the value of the original encoded signal.
[0020] The Shannon-Hartley Theorem has been applied using equal bandwidths for signal and for noise. The inventive technology described herein allows increased capacity due to cumulative sum of multiple virtual channels with each having a modulated frequency close to each other and still maintain nearly the same total bandwidth on the physical channel. In addition, as all these modulated frequencies (virtual channels) are transmitted onto the physical channel simultaneously their bandwidths significantly overlap. All intercarrier interference is removed by the present invention. The inventive technology described herein breaks this link by forcing the noise to pass through a substantially narrower bandwidth in the receiver while the signal occupies the full required bandwidth. This process causes the difference between the cumulative energy of the signal and the cumulative energy of noise to become greater. This results in a significantly increased channel capacity heretofore not thought achievable. Since the modulated frequencies of different channels overlap within a constrained bandwidth, inter-carrier interference is more dominant than other noise. The present invention reduces the impact of all of the noise to increase the overall capacity. This decoupling of the noise and signal bandwidth achievable with the present invention represents a completely novel application of the Shannon-Hartley Theorem. There are basically two reasons for this improvement in channel capacity. First, the present invention does not rely on a digital pulse signal to convey information. Rather, the present invention transmits information by communicating the amplitude of discrete sinusoidal signals that remain fixed in amplitude in the same period in which the change in status at the transmitter is occurring. There is no abrupt change in amplitude from one bit period to the next as there is when information is sent as a pulse. Each discrete interval has its own sine wave inputs that develop as sine waves with time. This means that there are no sources of wide band spectra in this communication system as there is when information transfer is based on digital pulses.
[0021] The present invention provides for a huge improvement in the signal-to-noise ratio by blocking the detrimental effect of all channel noise except for the noise resident within a narrow bandwidth carrying the transmitted information signal.
SUMMARY OF THE INVENTION
[0022] The invention described herein is a unique digital compression technology which increases the channel capacity of a bandwidth limited communications highway by using a combined coding and modulation technique. The technique results in an increase in channel capacity superior to what would be expected when determining bandwidth with the Shannon-Hartley theorem.
[0023] The inventive technique allows multiple independent modulated data streams to simultaneously share the same bandwidth without cross-channel interference. Unlike well known spread-spectrum methods, each data stream does not suffer from SNR degradation due to the presence of other channels. The inventive technique effectively increases the channel capacity of a communications highway by utilizing overlapping signals to carry additional information and by passing inherent noise through a narrow band filter in the receiver while the signal carrying information occupies the full bandwidth.
[0024] The invention further makes use of a matched filter system to reduce the error rate over the communication highway. The matched filter utilizes a unique training method based on performing a spectral response test which transmits a series of pure frequencies in a predetermined sequence over the communication highway. An algorithm is utilized to calculate the effect of the unique characteristics of the communications highway on the transmitted signal. Based on that calculation an ideal signal is created and stored in the matched filter for comparison with signals received at the receiver portion of the inventive transmission system.
[0025] These and other features of the invention will be more fully appreciated from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is an overview of the inventive transmission system,
[0027] FIG. 2A is a schematic of one embodiment of a super resonant filter utilized with the present invention,
[0028] FIG. 2B is a second embodiment of the inventive super resonant filter,
[0029] FIG. 3 shows a cascade arrangement of super resonant filters used in the receiver portion of the inventive transmission system,
[0030] FIG. 4 is a comparison of the inventive system with current ADSL technology, and;
[0031] FIGS. 5 and 6 show two possible embodiments of a matched filter for use with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Referring now to FIG. 1 there is shown an overall system block diagram of the transmit and receive portions of the present invention. The system shown in FIG. 1 is similar to the communications systems described in U.S. Pat. Nos. 5,956,372, 6,075,817 and 7,336,747, the teachings of all three patents being incorporated herein by reference. The present invention however achieves significant improvements to the systems shown in the above identified patents along with operational advantages.
[0033] As shown in FIG. 1 the transmitter section 30 of the present invention has multiple inputs, shown as inputs txbit ( 1 , 0 ) through txbit ( 7 , 6 ) applied respectfully to the inputs of multiplier circuits 10 - 13 .
[0034] In this exemplary embodiment an 8-bit input is split into four 2-bit words. Each 2-bit word is fed into its respective transmitter channel. There is no priori requirement for coding (for example randomizing, etc.) or arrangement of the 8-bit word before it is applied to multipliers 10 - 13 , nor is there any requirement for which bits are applied to a particular transmit channel.
[0035] The choice of 2-bits per channel, as opposed to 1 or 8-bits per channel, is based on the overall system requirements such as Signal-to-Noise Ratio (SNR), channel type, data rate, power levels, noise profile, etc. It is to be understood however that the number of bits per channel is not a particular limitation of the present invention. That is because the present invention is a channel coding system rather than a source coding system. The only input requirement is that each symbol period be pre-defined.
[0036] An exemplary symbol period T for one embodiment of the invention is 1 μsec or 1 mega symbol/sec. For this example the incoming 8-bit word must arrive at an exact rate of one word per microsecond.
[0037] Also applied to multipliers 10 - 13 is the output of Local Oscillators (LO) L 01 -L 04 . Each local oscillator is a pure sine wave with a pre-set frequency and a fixed amplitude and is unique to each transmission channel. Each local oscillator is pre-set for a given system to have the same fixed phase relationship at the beginning of each 1 μsec period so that each sine wave starts at a zero phase angle. As an example, in the case of a 1.00 MHz local oscillator, a 360 degree sine wave will be completed within 1 μsec and looks like a continuous sine wave across multiple symbol periods. The remaining local oscillators are, by definition, not continuous as they can be lower or higher in frequency than 1.00 MHz. However, there is a predetermined built in delay at the end of each microsecond symbol period in order to re-start at a prescribed phase angle for the new symbol period. As an example, for a 9 frequency application there can be four frequencies below and four frequencies above 1.00 MHz.
[0038] For one embodiment a range of frequencies around the center frequency of 1.00 MHz can be used. This range is affected by a number of factors, including overall system bandwidth and the fact that at least one peak of a sine wave is required at the output of each TXSRF (items 14 - 17 ). The required peak occurs at 90 and 270 degrees for each local oscillator. In this embodiment the highest frequency used was 1.30 MHz and the lowest was 700 KHz with a 1 msec symbol period. Three bits were modulated on each frequency, except for the highest and lowest frequency which modulated 2-bits each for a total of 25 bits/symbol.
[0039] The bits applied to each multiplier 10 - 13 , modulate the output of each local oscillator which is also applied to each multiplier as shown in FIG. 1 . The output of each multiplier is applied to respective inputs of TXSRF 1 -TXSRF 4 .
[0040] Referring now to FIG. 2A there is shown one embodiment of TXSRF 1 -TXSRF 4 . This Super-Resonant Filter (SRF) circuit is generally of the type shown and described in U.S. Pat. No. 7,336,747 which is incorporated herein by reference. Additional embodiments of a SRF circuit are also shown in U.S. Pat. No. 7,336,747. The SRF circuit shown in FIG. 2 A functions as a spike filter with a bandwidth of substantially less than 1/ T, where T is the symbol period, and having a response time of T.
[0041] The super-resonant filter shown in FIG. 2A has advantages over prior art spike filters. One such advantage is the fast settling time of the super-resonant filter. The SRF transmits only a single frequency at a specific phase of sinusoidal input. The inputs may include noise which is itself a compilation of signals.
[0042] The system operates on samples of the input signal over one symbol period T or less so there is no coherent relationship between successive symbol periods. Each symbol period T starts afresh, although within the symbol period T there may be several frequencies which may be recoverable by another TXSRF.
[0043] As shown in FIG. 2A input 51 receives the input signals, which are symbols represented by one cycle of a sine wave. The sine waves are sampled n times a symbol and the signals on input 51 have a frequency LO. The input signals are presented to adder 53 which sums the input samples and feedback samples. A squaring function is performed in circuit 54 . Circuit 54 multiplies the output of adder 53 by itself thereby producing the square of the adder 53 output. The output of circuit 54 is a voltage with a frequency of twice the input frequency LO. Local oscillator 55 oscillates with a frequency LO. The output of the local oscillator 55 and output of squaring circuit 54 are multiplied by multiplier 56 . Multiplier 56 provides an output comprised of 1 LO and 3 LO.
[0044] The output of multiplier 56 is presented to square root circuit 60 which provides the square root of the amplitude of the output of multiplier 56 . The output of adder 53 is also applied to sign extractor 61 . Sign extractor 61 extracts the sign of this signal which is used to multiply the output of square root circuit 60 in multiplier 62 . The output of multiplier 62 is fed back through delay unit 63 which delays the output sample pulses one sample period (i.e. 1/n).
[0045] In circuit 54 the x 2 operation provides sinusoids whose phase angle has doubled, i.e., x=a sin a becomes x 2 =a 2 sin 2 a or a 2 (sin 2a−1). When this signal is multiplied by the output of the local oscillator 55 outputting a signal of sine a, the result is a 2 sine a. This signal is exactly in phase with the input signal.
[0046] It should be noted that the sample of the signal is also in phase with the local oscillator LO. When the sample is delayed by one sample period (1/n), it adds to the newly received sample period. However, before this addition takes place, the square root of a 2 (sin 2a−1) sine a results in a sine a. Because the square root process removes the sign, it is necessary to ensure that the output of the square root process has the input sign restored.
[0047] When the local oscillator frequency is not exactly equal to the incoming frequency and phase, the operation is different. When the local frequency angle is a+φ, the output phase angle is 2a−a−φ which equal a−φ and when the local frequency angle is a−φ, the output angle is a+φ so whether the incoming signal frequency is above or below the desired locally selected frequency, the feedback delayed signal is out of phase with the input signal and does not add.
[0048] The addition of the samples amounts to an integration of the selected sinusoidal wave resulting in a peak signal of n/2π. The sample amplitudes are large over a 30 degree interval. Thus, the integration is most intense near the peaks of the input signal.
[0049] The integration of sequential sampling pulses requires that the spectrum of each overlap the other at the information channel frequency. Only this spectrum is needed to develop and transfer the information across the channel. Thus, the entire spectrum of the sampling pulse is not required.
[0050] The output at 64 is a summation of the amplitudes of the sample intervals which are T/n in time size (there are n samples per symbol period) and there is a positive peak at 90 deg., and a negative peak at 270 deg. The magnitude of the peaks are about n times the peaks of the input sine wave. The width of the output peaks approximate x (T/n), where x is in the order of 3 or 4 and is very narrow with respect to the symbol period. This permits successive symbols to be transmitted close together with a time separation slightly longer than x (T/n) without the output peaks interfering with one another. The above means that the bit throughput rate is n t n f where n t is the number of time samples per symbol and n f is the number of frequency channels per channel width. The output 64 derives its frequency from the frequency and spectrum of incoming signal 51 . Since only a line spectrum is presented to input 51 , the output must also be a line spectrum regardless of the time and frequency spacings of the input 51 . The line frequency spectrum means that the interference from channel noise is greatly reduced because that power increases directly with bandwidth whereas the information signal occupies only a limited bandwidth. Thus if the band of the channel must have a bandwidth of 1 mhz to pass a 1 microsecond pulse, the noise improvement is 10 6 or 60 db. This allows great distances or even larger data rates to be handled.
[0051] The spike filter shown in FIG. 2A has two important elements. First, there is a forward path element for the incoming signal consisting of squarer 54 , multiplier 56 with a LO and the square root ( 60 ) and sign extract ( 61 ) components. Second, there is a feedback path adding the output to the input which creates a small phase shift versus frequency of the forward signal path. This small phase shift is repeated n times such that the cumulative affect becomes significant enough in the course of a symbol period T to produce a narrow band, yet fast acting filter with a bandwidth substantially less than 1/T but with a response time of T.
[0052] It is also important to understand that the feedback loop comprising elements 53 - 55 and 60 - 62 provides both positive and negative feedback. Specifically, when presented with a desired signal (whose frequency is the same as the LO frequency), then the effect of the loop is positive feedback—causing the characteristic amplitude of that signal to increase. Likewise, when presented with an undesired frequency (such as an interferer whose frequency is different from that of the LO in that particular SRF, or wideband noise which is constituted of many other frequencies), the effect of all these elements within the loop (including summer 53 ) is to provide negative feedback which reduces (rather than increases) the characteristic amplitude of this signal.
[0053] The operation of the SRF at the receiving end is to simultaneously apply positive feedback to the desired signal, as well as negative feedback to the undesired signal(s). The final result of the receiver SRF's operation is actually in the differential behavior applied to all of its input signals combined, such that the net difference in phase response of the loop, applied many times (through the feedback process), is what ultimately causes the beneficial behavior of that system. In other words, it's not only “positive” or “negative” feedback, but rather the difference between these two effects as applied onto the desired vs. undesired signals. The combined multiple modulated frequencies (virtual channels) are used as the input to the SRF at the receiver. The local oscillator of the SRF is tuned to the desired frequency for data recovery. The LO and the desired modulated frequency are synchronized in phase and frequency. However the remaining modulated frequencies (virtual channels) have a phase offset with respect to the local oscillator. The SRF processes each symbol independently and is reset for the next symbol processing. The positive feedback is used in conjunction with a large number of samples, (e.g. 1 million) of these signals. The amplitude of each sample of the signal is cumulatively added with the previous amplitude and the cumulative amplitude of the modulated frequency (virtual channels) which is synchronized to the local oscillator, will have an amplitude increase faster than that of the frequencies that have phase offset with the local oscillator. In effect, the cumulative energy of the desired frequency is much larger than the cumulative energy of the other frequencies. This increased separation allows increased data rate.
[0054] The affect of the SRF loop is based on a continuum of phase shifts, which the feedback process “enhances” through numerous repetitions (“n” repetitions). For very close-in (but not center-frequency) signals, the phase shift is very small, but accumulates. Likewise, for frequencies that are further away, the phase shift is larger, but also cumulative. The term “far” frequencies is a relative term with the goal being the elimination of in-band interference. In conventional terms, this “far” frequency would be considered in-band, and too close to eliminate or to even reduce.
[0055] The term “characteristic amplitude” rather than to just plain “amplitude” is used in the discussion above. The reason is that the SRF does not merely amplify the desired signal, and attenuate the undesired signals, but it also changes the shape of the signals. That shape change is a by-product of the SRF process, and in of itself, is not of great consequence in the receiver. The critical factor is that the resulting new signal (output of the SRF) is mostly influenced by inputs at the center-frequency rather than by inputs at non-center-frequency (i.e., interferers or in-band noise). That the output of the receiver looks like a spike vs. a sinusoid is not important, as long as the amplitude of that spike is primarily due to the center-frequency input.
[0056] FIG. 2B is an alternative embodiment of the SRF but operates in the same way as described with respect to FIG. 2A . In this embodiment the output of the local oscillator is applied to a square root circuit and the output of the square root circuit is combined with the incoming signal on the forward path of the feed back loop. The reverse path of the feedback loop remains the same as shown in FIG. 2A .
[0057] Referring again to FIG. 1 the output of each TXSRF circuit contains the combination of the effect of the positive feedback SRF circuit, the combined amplitude of the incoming digital bits as well the input supplied by the local oscillator. All TXSRF channel outputs are summed in adder 18 to form the composite transmitted signal.
[0058] The line filter 19 ( FIG. 1 ) is a low-pass or band-pass filter. In the case of a typical telephone company line this filter would not necessarily be a physical circuit. Rather the filter shown in FIG. 1 is a model of the low-pass characteristics of the telephone line. There is no need to pre-filter the signal at its source as filtering takes place during transmission from transmitter 30 to receiver 40 . In the case of a wireless signal a filter of this type must be implemented at the transmitter to avoid interference with adjacent wireless bands with the harmonics of the transmitted signal.
[0059] In most wireless systems the signal output from adder 18 is typically up-converted to the band of interest for wireless transmission and then down-converted back to the chosen baseband frequency. The benefit of this wireless arrangement is that the baseband signal sees the entire wireless transmission path as a flat passband, within the baseband frequency range of interest, unlike its wired telephone counterpart which appears to the transmitted signal as a low pass path.
[0060] The output of LPF 19 is applied to RXSRF 1 through RXSRF 4 which are of the same configuration as the TXSRF shown in FIG. 2A . Each RXSRF is used to decode the received signal transmitted by the transmitter. Each RXSRF operates at the same frequency (delayed) as the corresponding TXSRF and is synchronized to a common clock reference. The clock reference can be transmitted to the receiver in any known manner (not shown) without any significant increase in band width.
[0061] FIG. 3 illustrates that the RX SRF circuits can be cascaded in series (as shown in FIG. 13 of U.S. Pat. No. 7,336,747) in order to increase the performance of the receiver system. This is particularly useful as more interfering channels are used on the transmit side in order to increase overall data throughput through a band-limited channel. Referring to FIG. 4 there is shown a plot of data rate versus distance when sending data over a typical TTP connection. As shown ADSL provides a data rate of approximately 9 Mbps at the data source which drops to 1.5 Mbps at 4000 feet from the source. In contrast the inventive system described herein can provide a data rate of 25 Mbps at 6000 feet and 3 Mbps at 20,000 feet which is a substantial improvement over ADSL.
[0062] The fundamental operation of the TXSRF/RXSRF combination is to reduce the effective noise bandwidth, but not equivalently reduce the signal bandwidth thereby allowing a “fast” signal to be transmitted and recovered where “fast” is relative as compared to the equivalent bandwidth. The use of almost (but not exactly) 100% overlapping signals to carry additional information is made possible by this noise-bandwidth reducing effect. To any one particular frequency channel utilizing the invention, the other overlapping data channels are considered “noise”. This is possible due to the inventive combination of the TXRSF, the RXSRF and the matched filter (described below).
[0063] As shown in FIG. 1 the output of each RXSRF circuit is applied to a matched filter 26 . The matched filter is a time-convolution filter which convolutes the incoming signal with pre-stored waveforms obtained during a training process, described below. Each pre-stored waveform corresponds to the combined effect of all incoming bits although the intent is to decode the 2 or 3 bits that are transmitted by a particular frequency with a particular symbol period. The other bits consist of bits from past symbol periods or from a current symbol period but from a different frequency. For each symbol of 1 μsec duration, and for each frequency, the matched filter performs the convolution and the best match is used to decode the detected 2 or 3 bits for that frequency channel.
[0064] FIG. 5 shows a typical arrangement of a matched filter. As illustrated the output of each RXSRF 1 - 4 is fed into delta-energy calculation modules 70 - 73 . Pre-stored wave forms (described below) are stored in waveform memories 74 - 77 and applied to the calculation modules which generate a score that depends on the difference between the incoming waveform and the pre-stored waveform. Best-fit select modules 78 - 81 then make a decision about the best-matched waveform, from the pre-stored series of “ideal” (no noise) waveforms. These ideal pre-stored wave forms have been previously computed and stored in the memory modules during the “training” phase of the connection, for example, when zero noise is added in order to have “ideal” waveforms for subsequent comparison with actual transmission waveforms which include noise.
[0065] FIG. 6 shows similar arrangement as FIG. 5 , except that the decision for the best-fit is made on a multi-channel basis in the best-fit select module 82 . Each RXSRF path still computes the list of scores for the incoming waveform as compared to all possible ideal waveforms. This list of scores is then combined with the similar list from all other channels and a system-wide decision is made as to the output bits. This approach can generally improve the overall noise performance when compared to the single-channel decision method.
[0066] The purpose of the training process is to store in memory the appropriate signal waveform. Typically training is performed by presenting the matched filter's input with the signal-to-be-detected, in a fashion where this signal is “ideal” i.e. has not been distorted and contains no noise. This technique is not always practical as it is normally not possible to turn off noise in a real world transmission channel. Other techniques involve the pre-computation of the matched filter's contents in a laboratory environment, rather than during usage in the field. Another technique performs a characterization of the transmission medium (for example, using spectrum analysis) from which the ideal waveform is computed indirectly and then stored in the matched filter.
[0067] Once the matched filter has been trained, it is ready for operation. The matched filter's output is not an analog signal. Rather, its output is a “score” as described above which indicates the likelihood of the presence of the desired signal at the input to the matched filter. Typically a threshold comparison on the output of the matched filter is used to decide if the signal was present with a sufficient probability of success.
[0068] The operation of the matched filter is a time-domain correlation, and is a known technique in communications and detection systems. One common method is to take the sum of the squares of the differences in time (the difference of the input waveform to the ideal waveform).
[0069] Imagine an ideal sinusoid overlaid on top the same sinusoid which has a slight distortion. Where the two waveforms are equal in amplitude, the difference is zero. Where they are not, the difference is a non-zero value. When this comparison is performed on two waveforms over a number of time points (samples) on these waveforms, a series of numbers is generated, each representing the fidelity of the input waveform to that of the ideal waveform, at each particular point in time. The square each of these values (so that they are all positive), is summed together to obtain the final matching score. Note that if the two waveforms are identical, then each difference point is zero, and the sum of these points is also zero. Hence, a zero score means an ideal match Likewise, a high score means there is less correlation between the incoming and ideal waveforms.
[0070] The more points in time that the comparison over the signal is performed the more accurate and the more resolution such a filter allows for comparing different but close-to-identical signals (i.e., more bits per symbol).
[0071] Training for a matched filter is performed for each connection and retraining can also be performed periodically. Generally, the training of a matched filter is done when the filter is manufactured as the signal to be matched is not expected to be altered by the transmission medium but rather to be corrupted with noise. Therefore with a typical matched filter the training of the filter is straightforward as it is known what the signal to be recovered looks like. For the present invention however the characteristics of a particular communications highway will effect the signal to be matched, and it cannot be known a priori the line characteristics to pre-program the matched filter.
[0072] Therefore in order to pre-program the matched filter with the present invention a line-specific or connection-specific spectral response test is performed. Such spectral response tests are known in communications technology and need not be further described herein. Based on the results of the spectral response test it is possible to calculate, with a pre-determined algorithm, the effect of a line's unique characteristics on the desired signal. After applying the pre-determined algorithm the resultant signal can then be stored as the training signal in the matched filter.
[0073] Various algorithms can be used but one exemplary algorithm for use with the present invention comprises the following steps;
(a) To determine the line filtering characteristics the transmitter transmits a series of pure frequencies in a predetermined sequence. An example is to sweep from 100 KHz to 1.5 MHz in 1 KHz steps for 1 μsec each. The receiver receives these frequencies and creates a spectral mapping of the line's passband to develop a spectrum analysis of the line. (b) The receiver uses the passband characteristics of the spectrum analysis in its internal simulation of the transmitter, line and receiver to compute the waveforms that the output of the RXSRF would present to the matched filter. (c) Repeat step (b) for each series of bit combinations. (d) Store the results of (b) and (c) in the matched filter.
[0078] Creating a spectral mapping to develop a spectrum analysis which is based on a line's passband is a known technique. Once the spectrum analysis has been developed computation of the waveforms required for the matched filter can also be accomplished utilizing known techniques.
[0079] Referring again to FIG. 5 rxbits ( 1 , 0 ) through rxbit ( 7 , 6 ) are generated by best-fit select modules 78 - 81 . The rxbits ( 1 , 0 ) through rxbits ( 7 , 6 ) are equal to txbits ( 1 , 0 ) through txbits ( 7 , 6 ) which were applied to transmitter 30 , thereby allowing accurate recovery of the transmitted signal at the receiver.
[0080] The description of certain embodiments of this invention is intended to be illustrative and not limiting. Therefore, although the present invention has been described in relation to particular embodiments thereof, many other variations and other uses will be apparent to those skilled in the art. It is understood therefore that the present invention is not limited by the specific disclosure herein, but only by the broadest scope of the appended claims. Possible and known variations for the circuitry described herein can be implemented in a number of different ways as long as the operation of the inventive system and method falls within the appended claims.
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A unique digital compression technology for increasing the information carrying capacity of a bandwidth limited communications path highway by using a combined coding and modulation technique. The inventive technology allows multiple independent modulated data streams to simultaneously and instantaneously share the same bandwidth without cross-channel interference. A matched filter is used to substantially reduce the error rate and utilizes a unique training method based on performing a spectral response test. An algorithm calculates the effect of the unique characteristics of the communications highway on the transmitted signal and generates an ideal signal stored in the matched filter for comparison with received signals.
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This is a Continuation, of Application Ser. No. 08/489,726, filed Jun. 13, 1995, now U.S. Pat. No. 5,677,578.
FIELD OF THE INVENTION
The field of the present invention relates generally to cable television and rf signal distribution equipment, and more specifically to multi-taps.
BACKGROUND OF THE INVENTION
In cable TV and other rf distribution systems it is typically necessary to tap off a television or rf signal from a main distribution cable for bringing the television or rf signal into a customers facility on a secondary cable. The signal tapped off is generally substantially attenuated through use of a signal tapping device. A known device for accomplishing this is a multi-tap, that permits connection to the main television or rf signal carrying cable, and provides multiple outputs for individual connection to a number of customers, respectively. In a typical cable television distribution system, a plurality of multi-tap devices are connected as required along the length of a main signal line for tapping and distributing television signals to a plurality of the customers located in a vicinity of the areas where the main cable is strung. In such an installation, it is common practice to pass the main cable into one multi-tap at an input port thereof, and to continue the main cable from an output port of the multi-tap for connection to the input port of the next multi-tap down line. As more customers are added to the system, it may be necessary to lengthen the line, and/or to increase the level of power of the main television signal being conducted by the main cable. It is also typical to have the main distribution cable conduct both the television or rf signal along with the ac power necessary to energize the electronic circuitry of each of the multi-taps. It is often necessary to open one or more of the multi-taps connected in cascade, in order to change a tap plate for changing the attenuation or signal levels of the signals tapped off for connection to customers, in order to maintain the customers' signal level at an appropriate level of power (an appropriate db level).
With known multi-taps of the prior art, whenever tap plates must be removed for substituting a new tap plate to obtain higher or lower attenuation, or to repair a particular multi-tap, the main rf signal and associated ac power for the multi-taps down line of the multi-tap being serviced are interrupted or cut off from the down line multi-taps. Accordingly, all customers inclusive of the customers associated with the multi-tap being serviced, and those down line, have their television signal connections interrupted until the servicing of the multi-tap under repair or conversion is completed. Many attempts have been made to overcome this difficulty.
A major problem with known multi-tap devices having some built in switching mechanism for permitting manual closure, for example, after a tap plate is removed, to reconnect the rf signal and ac power to the down line multi-taps, still cause an interruption of rf signal power and ac power to the down line multi-taps until the switching mechanism is activated. The present inventor recognized the need for providing improved multi-tap devices that can be repaired or converted to higher or lower attenuation factors without any interruption of rf signal and ac power to down line multitaps.
SUMMARY OF THE INVENTION
An object of the invention is to provide a new and improved multi-tap device.
Another object of the invention is to provide a multi-tap apparatus or device that insures uninterrupted signal and power to down line multi-taps connected in cascade, whenever a tap plate of an upstream multi-tap is removed.
With the problems of the prior art in mind, the present invention includes a shunt printed circuit board having an electrically conductive path thereon for carrying an rf signal and ac power between main cable input and output connectors of the associated multi-tap device. Whenever a tap plate of the multi-tap device is removed, switching means are provided for automatically connecting the shunt conductor of the shunt printed circuit board between the main cable input and output connectors before the tap plate pin connectors are completely disconnected from electrical sockets of the main housing of the multi-tap device, which would cause interruption of the rf signal and associated ac power to the down line multi-taps in the absence of the switching means. In other words, the switching means is operative for making an electrical connection between the main cable input and output connectors of the multi-tap before the tap plate is completely electrically disconnected from the input and output rf cables connected to the associated multi-tap device.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments of the present invention are described below with reference to the drawings, in which like items are identified by the same reference designation, wherein:
FIG. 1 is a pictorial drawing of the main housing portion of a known multi-tap device.
FIG. 2 is a pictorial drawing showing the cover plate secured to the opposite face of the multi-tap housing of FIG. 1, along with the associated output tap connectors for distributing a television signal to as many as four individual customers, in this example.
FIG. 3 shows the interior assembly of the tap plate as secured to the inside face of the tap plate cover for a multitap housing cover.
FIG. 4 is a pictorial of the interior of the prior multitap apparatus of the main housing with the tap plate/cover removed, exposing two seizure socket assembly housings.
FIG. 5 is a pictorial illustration of the interior assembly of a main housing cover and tap plate for one embodiment of the invention.
FIG. 6 is a pictorial illustration of the interior of the main housing with the associated cover and tap plate assembly removed, exposing two seizure socket assemblies, portions of a shunt printed circuit board, and switching mechanism cam heads for one embodiment of the invention.
FIG. 7 is an exploded assembly diagram for one embodiment of the invention.
FIG. 8A is a t op view of a prior seizure socket spring insert.
FIG. 8B is a cross sectional view taken along 8B--8B of FIG. 8A.
FIG. 8C is a bottom view of the seizure socket spring insert of FIGS. 8A and 8B.
FIG. 9A is a top view of a modified seizure socket spring insert for one embodiment of the invention.
FIG. 9B is a cross sectional view taken along 9B--9B of FIG. 9A.
FIG. 9C is a bottom view of the modified seizure socket spring insert of FIG. 9A.
FIG. 10A is a longitudinal cross sectional view of a seizure socket of one embodiment of the invention.
FIG. 10B is a side elevational view taken from the right side of the seizure post of FIG. 10A.
FIG. 10C is a top view of the seizure post of FIG. 10A.
FIG. 11 is a pictorial view of a cam for one embodiment of the invention.
FIG. 12 is a pictorial view of a spring contact for one embodiment of the invention.
FIG. 13A is a pictorial view of the top of a contact ring for one embodiment of the invention.
FIG. 13B is a side elevational view of the contact ring view of FIG. 13A.
FIG. 14A is a top view of a printed circuit board and its associated electrical conductor path for one embodiment of the invention.
FIG. 14B is a side elevational view of the printed circuit board of FIG. 14A.
FIG. 15 is a partial cross sectional and pictorial view of an interior portion of the multi-tap device for showing features of the switching mechanism for one embodiment of the invention, with the switching mechanism in an open switch or inactive condition.
FIG. 16 is a partial cross sectional and partial pictorial view of a portion of the multi-tap device showing the switching mechanism in an activated state with the cover plate and associated tap plate at an intermediate position just before removal from or just upon initial installation into the main housing, for one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, the main housing 2 is shown to include in this example an in-line output port 4, an in-line input port 6, a parallel output port 8, a parallel input port 10 and port caps 12 screwed into the parallel output port 8 and parallel input port 10, respectively, in this example. Mounting bosses 14 are provided for securing a tap plate cover 26 to the other side of the housing 2 (see FIG. 2). A clamp plate 16 is secured to the housing 2 via a clamp bolt 18. A clamp boss 20 is provided for receiving the clamp plate 16 and clamp bolt 18. The clamp boss 20 also includes a clamp groove 22 for in combination with an opposing groove or channel of the clamp plate 16, permitting the multi-tap device to be secured to an appropriate mounting post or member (not shown). A portion of an output tap connector 24 is also shown.
With further reference to FIG. 2, the opposing face of the multi-tap device of FIG. 1 is shown to include in this illustration four output tap connectors 24, respectively. However, any desired number of output tap connectors may be provided to a practical limit, and also less than four output tap connectors 24 may also be provided. The tap plate cover 26 is secured to the main housing 2 via captive mounting screws 28, as shown. Note that the output tap connectors 24 are mounted on the cover plate in a manner permitting electrical connection to the respective connectors 24 from the inside or bottom face of the tap plate cover 26. For at least one embodiment of the invention, the multi-tap housing configuration of FIGS. 1 and 2 remains unchanged. However, the present invention is not limited to the aforesaid configuration of FIGS. 1 and 2. The tap plate cover 26 also includes mounting screw bosses 30, respectively, for receiving the captive mounting screws 28, respectively, in this example.
With reference to FIG. 3, the assembly of the tap plate printed circuit board 42 to the interior side of the tap plate cover 26 is shown. Tap plate printed circuit board 42 is secured thereto via mounting screws 40. Individual electrical connections (not shown) are made between circuitry on printed circuit board 42 and the output tap connectors 24, respectively, for providing attenuated TV signals to each of the connectors 24, respectively. In this example, the top of an electrical connection post 39, is located at the rf and/or ac power output to the tap plate 42, and the electrical connection post 37 is located at the rf/ac power input of the tap plate 42. Also shown in this example are threaded mounting screw holes 32, a weather or rubber gasket 34 for providing a weather tight seal between the tap plate cover 26 and the main housing 2. Also, an rf gasket 36 is incorporated in the tap plate cover 26 for providing rf shielding to the associated multi-tap device.
With reference to FIG. 4, the tap plate 42 of FIG. 3 is removed, exposing the underlying seizure socket assemblies 52 of the known multi-tap device, which are mounted in the main housing via mounting bosses 56 on the socket assembly housings 52 and mounting screws 58, as shown. Holes 55 are provided in the tops of the seizure socket assembly housings 52 for providing access to seizure sockets 54, as shown. As will be described in greater detail below, the seizure sockets 54 are adapted for receiving the electrical connection post 37 and 39, respectively, for connecting the input and output main rf cable to the tap plate 42. Obviously, the main TV signal for attenuation by circuitry on the tap plate 42 for connection to connectors 24 is derived from the signal brought in on electrical connection post 37. In this example, the main housing 2 further includes a step-down recess 44, a channel 46 for receiving the o-ring 34, and a protruding lip 48 for engaging the rf gasket 36 installed in the cover 26, as indicated above. Otherwise, the interior portion of the main housing 2 with seizure socket assemblies 52 installed as shown, is further configured to have sufficient depth and open area for accommodating the components (not shown) of the tap plate 42.
With further reference to FIG. 4, both of the seizure socket assemblies 52 are configured for permitting an rf cable securement screw 60 in each assembly housing 52 to be rotatable along with its associated seizure socket 54 through 90°. For purposes of further illustration, please refer to FIGS. 10A through FIG. 10C, showing a seizure socket 54 in detail. The center conductor of an rf cable, in this example, installed through output port 8 is inserted through the hole 132 of socket 54, the associated set screw 60 screwed into hole 134 is tightened against the center conductor of the output rf cable (not shown) for securing the same to the associated seizure socket 54. In a like manner, an input rf cable has its center conductor secured through input port 10 to the other seizure socket 54. In this latter example, the associated rf input and output cables (not shown) are in parallel to one another at least where they exit from output and input ports 8 and 10. Note that in the positioning of the set screws 60 shown in FIG. 4, they can be tightened or loosened by inserting a screwdriver through the other output port 4 and the other input port 6, where after port caps 12 are screwed into ports 4 and 6 for closing them of f. If it is desired to have the input rf cable installed through input port 6, screw 60 is rotated through 90° to be positioned opposite input port 10, for permitting the input rf cable to be installed to the seizure socket 54 through input port 6 and a screwdriver into port 10, in a manner as previously described. Similarly, if it is desired to install the output rf cable through output port 4, the associated set screw 60 of the left-hand socket assembly 52, in this example, is rotated through 90° to be opposite output port 8, with output port 4 providing access by a screwdriver to the associated set screw 60.
Note that the particular known multi-tap device illustrated in FIGS. 1-4 is a model MGT24-11, sold by Antornix Inc., of Cranbury, N.J. As described below, the present invention is illustrated as a modification of this known multi-tap configuration, but is not limited thereto, in that the various features of embodiments of the present invention are applicable for use in many other multi-tap configurations, as would be understood by one of skill in the art.
With reference to FIG. 5, in one embodiment of the invention an insulator cover 62 is installed over a portion of the tap plate printed circuit board 42, as shown. The cover 62 provides both protection of underlying electrical components (not shown) protruding from the tap plate printed circuit board 42, in addition to improved electrical isolation thereof.
With reference to FIG. 6, in a preferred embodiment of the invention, the seizure socket assemblies 52 of the known device are modified to be configured as shown by the seizure socket assemblies 64. As will be described in greater detail below, and further with reference to FIG. 7, holes 72 are provided through the top portion of the socket assembly housing 78 for permitting the cam head 136 of a cam 88 to protrude through one of the holes 72 depending upon whether the particular modified seizure socket assembly is to be used at the input or output side of the associated multi-tap device. In the example of FIG. 6, the cam heads 136 protrude through an associated hole 72 and are covered by a cam spring cap 68. Note that the cam spring cap 68 is only used in applications where dimensional tolerances of the associated multi-tap device require the, cam spring caps 68, for increasing the effective surface area of the cam heads 136. A shunt printed circuit board 70 is secured via mounting screws 58 to the modified seizure socket assemblies 64, respectively, as shown. An electrical conductive path 76 for rf signals and ac power is provided o n the s hunt printed circuit board 70. Rivets 74 are used for attaching spring contacts 96 to protruding tabs 144 (see FIG. 7) of printed circuit board 70 as shown.
With further reference to the exploded assembly view of FIG. 7, showing the assembly of the left-hand modified seizure socket assembly 64 with the shunt printed circuit board 70 and associated spring contact 96, it should be noted that the right-hand modified seizure socket assembly 64 is similarly connected to the other end of printed circuit board 70 and associated spring contact 96, as further illustrated below. As shown, the assembly includes the top portion 78 of socket assembly housing 64, the lower portion 80 thereof, mounting bosses 82 of associated top portion 78 and lower portion 80 of housing 64, associated screw holes 84 of the latter, a hole 86 in the top portion 78 for receiving the upper portion 57 of seizure socket 54, a central hole 85 through the lower portion of socket assembly housing 52 for receiving the lower portion or section 59 of seizure socket 54, a stop tab 90 on cam 88, a contact ring 92 mounted on a central portion 93 of seizure socket 54 for electrical connection therebetween, a stationary contact 94 of contact ring 92, a spring contact head 98 of spring contact 96, a modified seizure socket spring insert 110, and mounting screw holes 140 of shunt printed circuit board 70. Note that as will be discussed in further detail below, in the preferred embodiment of the invention, the modified spring insert 110 of FIGS. 9A through 9C is used, but alternatively the prior spring insert 100 shown in FIGS. 8A through 8C can also be used. With further reference to FIG. 7, note that the lower socket assembly housing portion 80 includes a 90° step down portion 87 that forms one half of a 90° open slot with a similar step down portion of the top socket housing portion 78 (not shown), for providing a 90° open slot for permitting rotation of the set screw 60 and its associated seizure socket 54, as previously described for the known multi-tap device illustrated.
With reference to FIGS. 8A through 8C, the known multi-tap device illustrated in FIGS. 1 through 4 further includes a seizure socket spring insert 100 for insertion into the top of the seizure socket 54, as shown in FIG. 7. The spring insert 100 adapts the seizure socket 54 for receiving one of the electrical posts 37 or 39 of tap plate printed circuit board 42, in this example. As shown, the prior spring insert includes top retaining tabs 102, a bottom flange 104, side retention tabs 106 for securing the spring insert 100 into an associated socket 54, and downwardly converging sidewall portions 108.
As previously indicated, the spring insert 100 can be used in the assembly of FIG. 7 in substitution for the preferred spring insert 110, but best performance will be obtained through use of the modified spring insert 110. The latter is shown in detail in FIGS. 9A through 9C, as will be immediately described. The preferred spring insert 110 includes substantially parallel side wall portions 112 having an inside diameter dimensioned for insuring that electrical contact will be maintained with one of the electrical pins 37 or 39 of tap plate 42 as long as a portion of a pin is located between the interior sidewall portions 112 of spring insert 110. The preferred spring insert 110 also includes top retaining tabs 114, and side retention tabs 116. Note that the converging downward interior sidewalls 108 of the prior spring insert 100 will cause electrical contact with one of the electrical pins 37 or 39 of tap plate printed circuit board 42 to be interrupted before the associated pin is completely withdrawn from the spring insert 100, which is undesirable as will be shown from the below described description of the operation of the invention.
The seizure socket 54 is shown in detail in FIGS. 10A through 10C. The configuration shown is as used in the previously described known multi-tap device illustrated in FIGS. 1 through 4. The seizure socket 54 includes an upper section 57, a lower section 59, a central portion 93, a hole 130 for receiving a seizure socket spring 100 or preferably 110, a hole 132 for receiving an rf conductor, and a threaded hole 134 for receiving the rf cable securement set screw 60.
FIG. 11 is an enlarged pictorial view of cam 88. As shown, the cam is T-shaped, and includes a base portion 138, and a stem portion terminating in a cam head 136. A stop tab 90 is shown in this example for limiting the extreme downward travel of cam 88 when in use, as will be described below. The cam may be made from any suitable plastic material such as Delrin®, for example. Note also that the seizure socket assembly housing 52, and the modified housing as used in the present invention, can be made from any suitable plastic material. The width of the bottom of the base 138 is curved as shown to have a straight section 139 followed by a curved section 141. The straight section 139 substantially limits the bending of spring contact 96 as described below. The curved or convex section 141 permits a greater degree of tolerance for dimensional variations in the tap plate 42, the main housing 2, and the cover 26, for providing acceptable cam 88 operation or movement in bending spring contact 96, while preventing over bending thereof.
An enlarged pictorial view of the spring contact 96 is shown in FIG. 12. As shown, the spring contact 96 is shaped to include at one end a mounting hole 97, and at its other end a spring contact head 98.
The stationary electrical contact 94 is provided as part of a contact ring 92 as shown in FIGS. 13A and 13B. More specifically, the contact ring 92 includes mounting tabs 95 about the inner circumference of the ring portion thereof, as shown.
In FIG. 14A, a top view of the shunt printed circuit board 70 is shown to include a conductor path or metallization 76, two outwardly extending tabs 144 proximate either end, respectively, with each tab 144 including a rivet hole 142, as shown. Also, screw holes 140 are provided at either end of the shunt printed circuit board 70. A side elevational view or edge view of the shunt printed circuit board 70 is shown in FIG. 14B.
Note that the seizure socket spring insert 100, and modified insert 110, can be fabricated from any suitable electrically conductive material. In this example, the material is nickel plated phosphor bronze. Also, the main housing 2 and cover 26 may be fabricated from any suitable material. For example, they can be fabricated from cast aluminum material. Spring contact 96 and contact ring 94 may be fabricated from phosphor bronze, or any other suitable electrically conductive material.
FIG. 15 shows a partial cross section and pictorial view through a modified seizure socket assembly 64, with the tap plate cover 26 and associated tap plate 42 secured in place to the main housing 2. As shown, the printed circuit board 42 pushes against the cam spring cap 68 for forcing the cam 138 downward against spring contact 96, causing the spring contact 96 to be disconnected from the stationary contact 94, that is the switch provided by spring contact 96 and stationary contact 94 is in its open condition. Also, an electrical connection post 37 is engaged within a seizure socket spring insert 110 for electrical connection to the input rf cable, in this example. Note that for sake of simplicity the center conductor of the associated rf cable is not shown, but it is assumed that it would be secured within the seizure socket 54 via the rf cable securement screw 60. Note also that in this example, a wedge stop 146 for limiting the travel of spring contact 96 is secured within the modified seizure socket assembly 64. However, it is expected that in many applications the wedge stop 146 will not be used. Its purpose is to prevent over bending of spring contact 96 to the extent that it will lose its memory for returning to its rest position for engaging stationary contact 94 whenever the cam 138 can be pushed upward via the spring tension of spring contact 96 when the tap plate cover 26 and associated printed circuit board 42 are removed, as will be described further.
An important aspect of the present invention is that the switching configuration provides for spring contact head 98 to mechanically contact and electrically engage the stationary contact 94 before the electrical connection post 37 disengages from electrical interconnection with the modified seizure socket spring insert 110. This feature is illustrated in FIG. 16, showing the positioning of a various associated elements at a time when the tap plate cover 26 is about to be completely removed from the main housing 2, or is at the initial stage of just being installed onto the main housing 2. In this manner, the input cable is always electrically connected to the output cable, either via tap plate pcb 42 when cover 26 is installed on housing 2, and/or via the electrical conduction path formed by the seizure sockets 54 of electrical conductive material connected to input and output cables, contact rings 92 with respective stationary contacts 94, to spring contacts 96 electrically connected to opposite ends, respectively, of the metal path 76 of pcb 70.
With further reference to FIGS. 7 and 15, note that to insure good electrical contact between the spring contact 96 and the electrical conduction path or metallization 76 on printed circuit board 70, solder 150 is deposited therebetween, as shown.
With further reference to FIGS. 15 and 16, for purposes of simplicity, the example shown is with relation to the input side of the multi-tap device. However, the output side relative to the present invention is configured in substantially the same manner with the output rf cable secured to the output seizure socket, and operates in the same way, for providing the previously described switching action, and so forth. Also, in different applications, depending upon the configuration of the tap plate 42, the electrical connection post 37 may be associated with the output side, and the electrical connection post 39 with the input side.
Although various embodiments of the present invention have been shown described herein, they are not meant to be limiting. Those of skill in the art may recognize various modifications to the present invention, which modifications are meant to be covered by the spirit and scope of the appended claims. For example, the spring cap 68 may include a coil spring 66 for permitting the cap to move further onto the cam 88 after the spring contact 96 has reached its maximum allowed bending, in order to provide further latitude for dimensional tolerance variations in the main housing 2, cover 26, and tap plate printed circuit board 42. Note that the tension of the spring 66 is typically made greater than the spring constant of bending for spring contact 96.
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A multi-tap device for tapping a main TV or rf signal to deliver attenuated signals to individual TV receivers includes a pair of socket assemblies for receiving input and output pins of a plug-in tap plate or printed circuit board carrying necessary attenuation/tap off circuitry. The socket assemblies connect the input pin to a main input cable for receiving the main rf signal and ac power, and connect the output pin to a main output cable or continuation of the main cable, for distributing the main rf signal(s) and ac power to cascaded down line multi-tap devices. A shunt printed circuit board is mounted between the socket assemblies, and has an rf/ac conductive strip for connection at either end to switches built into each socket assembly. As a tap plate is removed or unplugged from the socket assemblies, the switches operate to close before the input and output pins are electrically disconnected from sockets of the socket assemblies, for electrical connecting the input and output cables together to insure that the rf signals and ac power is continuously delivered to down line multi-tap devices without interruption.
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TECHNICAL FIELD
[0001] The present invention relates to a method and device for taking up fish from a body of water for slaughtering, control, scientific examination, treatment and/or transfer to a net cage, transport container or the like. A specific embodiment of the invention relates to fish farming.
BACKGROUND ART
[0002] Fish is often held in net cages in industrial farming in coastal districts. The mostly used net cages comprises a ring formed floater onto which a fastened to define and enclosure for the fish to be cultured therein. The fish is kept at a relatively high density in the net cage and has to be treated to avoid parasites, such as salmon louse and other illnesses at planned intervals or according to the need thereof. The treatment may be performed by taking up the fish for injections, or by covering the net cage by means of an outer bag shaped impermeable tarpaulin or the like, and mixing in chemicals for treatment of the fish into the water inside of the tarpaulin.
[0003] Both for taking up fish and for treatment inside the net cage covered by an impermeable tarpaulin or the like, the volume inside of the net cage has to be reduced to further increase the density of the fish inside the net cage. This is done by partly lifting up the net cage to reduce the volume thereof. The lifting of the net cage requires lifting equipment as cranes and the like that are expensive in use and exposes the net cage for physical stress that may damage the equipment. The reduction of volume may cause stress with the fishes inside the net cage, and even physical damage to the fish due to the increased fish density.
[0004] Normally, specialized pumps are used for taking up the fish. The pumps do also expose the fish for further physical damage and further stress, which may also result in increased mortality. If the fish is taken up for slaughtering, the physical damage and stress may have effect on the quality of the fish and thus the sales value thereof.
[0005] For in situ treatment against e.g. salmon louse using an impermeable tarpaulin or the like outside the net cage, time is an important issue as the chemical used are poisonous to the fish by long time exposure, and as the tarpaulin reduces or even stops the introduction of fresh oxygen rich water into the net cage. The treatment time is a compromise between obtaining a sufficient treatment time and reducing the poisoning and/or drowning (i.e. dying due to lack of oxygen) of the fish to a minimum.
[0006] Methods and allowing migrating fishes between waters separated from each other's, or where waterfalls prevents fish from swimming upstream, are known from the prior art.
[0007] Salmon ladders are well known ways for providing a way for e.g. salmon and trout to pass dams and waterfalls that are too high to pass. A salmon ladder normally comprises several small dams connected by small waterfalls that may be passed upstream by the fish. SE527974 relates to a variant of a salmon ladder where a tubular member is connecting two separate water basins at different levels. The tube has different diameter along the length thereof to obtain a varying velocity of flow in different parts of the tube. GB2299920 relates to a floating fish pass connecting two water basins at different levels, the fish pass being a channel having rectangular cross section, where the fish is allowed to swim upstream in the flowing water.
[0008] FR2666960 and US20100086357 both relate to eel passes, comprising a slanting channel having a bottom portion covered with a bristle substrate to imitate grass. The bristle substrate is kept wet by irrigation with water for keeping the bristle substrate sufficiently wet to imitate the wet grass in which eels normally migrate between waters. According to FR2666960, a collecting sump for collecting eel falling over the upper edge of the slanting channel is arranged to collect the eels and to lead the eels into a tubular member to transport the eels together with water to a location where the eels are to be released. It is mentioned that eels may be taken out here for weighing, etc.
[0009] An object for the present invention is to provide for a method and a device for taking up fish, such as trout, salmon, char, or any other fish naturally migrating against flowing water, and thereby using the instincts of the fish for transfer of the fish to another net cage or transport container, for treatment and/or control, or for slaughtering, and at the same time avoiding the problems of the prior methods and devices.
[0010] Other object will be clear for the skilled person in reading the present description and claims.
SUMMARY OF INVENTION
[0011] According to a first aspect, the present invention relates to a A method for taking fish up from a body of water comprising the steps of:
providing a duct having a lower open end below the water surface and an upper open end arranged at a floating working platform above sea level, introducing water into the duct from the upper open end to give a water stream from the upper open end of the duct to the lower open end of the duct, and allowing the fish to swim up in the duct against the water stream therein,
wherein the incoming water is directed to flow into the duct, and that the fish is separated from the flowing by means of a grating inclining from the top end of the duct to a separation plate arranged above the water level in the duct.
[0015] The instinct of many fish species tells the fish to swim upstream as they do in the nature. Fish swimming upwards will end up at the top of the duct and may be taken from there for control, treatment, sorting, slaughtering, etc. By using the instinct of the fish, the stressful situations as mentioned on the introduction of the description are avoided, both reducing the stress of the fish and situations that may cause physical damage to the fish.
[0016] According to a first embodiment, the fish is led from the grating to the separation plate by its own swimming speed, and is led further from the separation plate into a processing duct. By taking advantage of the swimming speed of the fish and only leading the fish onto the separation plate and further into a processing duct, the device may be kept simple and easy to maintain, at the same time as devices that may stress or even damage the fish, may be avoided.
[0017] The processing duct may be provided for processing the fish swimming up the present device. One possible process may be that the fish is sprayed with chemicals in aqueous solution in the processing duct.
[0018] The fish may alternatively or additionally be sorted according to present parameters in the processing duct. The fish that is released from the processing duct after being sprayed with chemicals and/or sorted may be introduced into one or more cage net (s) and/or containers.
[0019] According to one embodiment, the fish is led into a facility for slaughtering of the fish.
[0020] According to one embodiment, the body of water is body of water inside of a sea farm enclosure, such as a cage net.
[0021] According to a second aspect, the present invention provides a device for taking up fish from a body of water, the device comprising:
a duct arranged connected to a working platform above sea level where the duct is arranged to be placed with a lower open end at the surface of the water, and an upper open end arranged at the working platform; a water source for introducing water into the duct at the upper open end of the duct to give an artificial waterfall through the duct,
wherein a grating is arranged upwards inclining from the upper end of the duct to a separation plate arranged above the water level in the duct, for leading the swimming fish from the duct onto the separation plate.
[0024] According to one embodiment, the water source is a pumping arrangement is arranged for pumping up water from a depth and introducing the water into the duct.
[0025] According to one embodiment, the water pumping arrangement comprises a vertically arranged tube that at is upper end is connected to a water inlet for introduction of water into the duct, and is open in its lower end, and where an air tube is arranged for introduction of air into the lower open end of the tube. This type of pumping device is a simple, and reliable pumping device only needing a compressor or other source of compressed air at the working platform, and no submerged moving parts needing maintenance, making it a cost efficient solution. Water pumped up from a depth is normally colder than the surface water. The cold water combined with introduction of air into the water, give an oxygen rich water in the duct. Fish tends to be attracted by water being more oxygen rich than the water where they are swimming. Accordingly, the use of this kind of pumping device will increase the efficiency of the present device in getting up fish, especially from fish farming cage nets or the like, where fish density may be so high that keeping a sufficiently high oxygen concentration in the water may be a challenge.
[0026] According to one embodiment, the device further comprises a processing duct for processing of the fish.
[0027] According to one embodiment, the processing duct comprises spray nozzles for spaying of fish with aqueous solutions of chemicals.
[0028] According to one embodiment, the processing duct comprises detectors for measuring weight, size, number etc. of the fish passing through the processing duct.
[0029] According to another embodiment, the processing duct comprises equipment for injecting medicine and/or identification markers into the fish.
BRIEF DESCRIPTION OF DRAWINGS
[0030] FIG. 1 is a side view of a net cage and a device according to the present invention,
[0031] FIG. 2 is a perspective view of a net cage and a device according to the present invention,
[0032] FIG. 3 is a detail view of a separation part of the present invention, and
[0033] FIG. 4 is a partly cut through side view of a treatment zone of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0034] FIG. 1 is a side view illustrating of a net cage 1 and a device according to the present invention. A ring shaped floater 2 connected to a bag-shaped net 3 forms the basic part of the net cage 1 . The skilled person will know that a net cage will normally comprise additional elements, which are irrelevant for the understanding of the present invention.
[0035] A device according to the present invention is arranged on a float 4 . The illustrated float 4 is a catamaran comprising a deck structure 5 connecting two hulls 6 , 6 ′. The float 4 may also comprise propulsion means, indicated by two outboard motors 7 . The float 4 forms a basis and support for the present device. The skilled person will understand that the float 4 may be a small vessel as illustrated, or a larger vessel. It is also possible to arrange a device according to the present invention permanently or temporary on a structure connected to the ring shaped floater 2 .
[0036] A tube 10 is arranged substantially vertically downwards from the deck structure 5 . The tube 10 is preferably made of a flexible material, such as tarpaulin material, or tarp, for easy uptake and putting out of the tube for transport of the device, as will be further described below. Preferably, rings or a helix of metal or any other suitable material are/is preferably attached to the flexible tube material to prevent that the tube collapses in use. At its lower end, the tube is held in down by means of a weight body 11 . The illustrated weight body 11 is a ring shaped body, which also is arranged to keep the lower opening of the tube 10 open. Lifting wires 9 are in their lower ends connected to the weight body and are connected to the lower end of the tube 10 . The lifting wires 9 are arranged inside the tube 10 or are arranged in channels in the tube walls. The lifting wires are connected to a winch 8 at the floater for lifting and lowering of the tube 10 .
[0037] An air tube 12 is also arranged from an air compressor at the deck structure 5 to a position below the lower opening of the tube 10 , ending in one or more nozzle(s) as air distributors arranged so that the air raises towards the water surface through the tube 10 . The illustrated air tube 12 is arranged inside the tube 10 and is lifted or lowered together with the tube 10 .
[0038] A compressor 19 is arranged on the floater for production of compressed air for the air tube 12 . The air is released immediately below the lower opening of the tube 10 . The air streaming upwards inside of the tube 10 will cause water to flow upwards together with the air and will lift the resulting water column above the sea level to a level depending on the airflow. The upper opening of the tube 10 is connected to a water inlet 13 at the deck structure 5 for introduction of the water into a duct 14 , arranged from the water inlet 13 and ending below the water surface inside of the net cage as an artificial river. The duct 14 is preferably held in the required angle to the water surface by means of pontoons 15 connected to the duct and floating at the water surface.
[0039] Fish like trout, salmon, and char, and relatives thereof living at least parts of their life in fresh water in the wild tend to swim against a current caused by flowing water, and more so if the incoming streaming water is more oxygen rich than the surrounding water basin. The water flowing down the duct is oxygen rich due to the use of the above-described “air pump” action. Additionally, as the water withdrawn from a depth, such as e.g. 10 to 100 meters, such as 20 to 50 meters, normally is colder than the water close to the water surface, even more oxygen may be dissolved in the water. The length of the tube 10 is adjusted to the preferred depth for taking in water at the place of use.
[0040] The skilled person will understand that the present method and device is not dependent on the use of the above described “air pump” action, and that any other convenient pump may be used without leaving the scope of the invention. The air driven pump as described above where water is caused to flow upwards in the tube 10 by countercurrent flow with air blown into the tube, is the presently preferred pump as it is simple and adds oxygen to the water. If mechanical pumps are used, air or oxygen might be added to the water before introduction into the duct 14 .
[0041] Provided that the fish in the cage net is of a species attracted to running, and oxygen rich water, the fish in the net cage will be attracted to the flowing water in the duct and will start swimming upwards the duct. It is assumed that an inclination of the duct of about 0.2% to about 5%, i.e. an inclination of 0.2 cm per meter, to 5 cm per meter from the sea level to the top of the duct. It is assumed that the most preferred inclination will be from about 0.4 to 3%, such as 0.5 to 2.5%, dependent on the fish species to be taken up.
[0042] The water inlet 13 is connected to the duct 14 so that the water is directed into the duct. A separation plate 17 is arranged at a level above the level of the streaming water to avoid the upcoming water to flow in any other direction. A grating 16 is arranged to prevent the fish from swimming down into the tube 10 and to lead the fish up on the separation plate 17 . The grating is inclining upwards from the upper end of the duct, so that fishes swimming upwards the duct 14 are lifted up by means of their own speed and the tilted grating 16 onto the separation plate 17 .
[0043] The fish entering the separation plate 17 has a speed sufficient to slide over the separation plate and into a processing duct 18 . The processing duct is preferably slightly obliquely arranged so that the incoming fish slides from the separation plate 17 downwards the processing duct 18 . The inclination of the processing duct may be from about 0.1 to 2%, such as from 0.2 to 1% from separation plate towards the sea level. Fish entering the processing duct will normally move through the processing duct by the speed at which they enter the processing duct and their own swimming movement so that only a small inclination as indicated is necessary for the fish to move through the processing duct. The length of the processing duct is adopted to allow for the required process step(s) to be performed in the processing duct. Dependent on the needs and specific setup, different processing steps may be performed as the fish passes through the processing duct. Additionally, or alternatively, the fish may be led from the processing duct into specific treatment sections to ascertain that the treatment is finalized.
[0044] The skilled person will understand that a duct with grating at its bottom part may be arranged between the separation plate 17 and the processing duct 18 for further separation of water from the fish, if needed.
[0045] The embodiment illustrated in the figures includes equipment for treatment of the fish by spraying the fish with relevant chemicals. The chemicals in question may e.g. be chemicals for treatment against salmon louse or other parasites or illnesses.
[0046] For such treatment, an aqueous solution of the relevant chemical(s) is introduced through spraying nozzles 20 arranged on a nozzle tube 21 above the fish sliding through the processing duct. A collection sump 22 covered by a grid 23 to allow water and chemicals is arranged in the bottom of the lower end of the processing duct, to collect water and chemicals and reduce the release of chemicals into the surroundings. The fish slides at the top of the grid 23 and into a fish outlet tube 24 .
[0047] A chemicals outlet tube 25 is connected to the sump for withdrawing the used aqueous solution of chemicals for the treatment. The used solution may be recirculated into the nozzle tubes 21 and nozzles 20 by means of a treatment liquid pump 26 . A not shown bleed tube is preferably arranged to withdraw a part of the solution collected in the sump for deposition. Additionally, a not illustrated chemicals addition tube connected to a chemicals tank is preferably provide to add chemicals to the circulating treatment liquid to substitute loss of chemicals, to adjust the concentration of chemicals in the circulating liquid due to dilution thereof by water following the fish, and to substitute loss of chemicals and any bled off of chemicals.
[0048] The skilled person understands that parts or all of the duct 14 , separation plate 17 and/or the processing duct 16 is covered, to avoid that any of the fishes escapes over the edges of the duct or further parts of the device. A cover 28 is illustrated over a part of the duct 14 .
[0049] The illustrated fish outlet tube is arranged to release the treated fish into the same cage net from which it was taken up. The skilled person will understand that the fish outlet tube 24 can be arranged to release the treated fish into a different cage net, to ascertain that all the fish in one cage net to be treated is treated, and that only the treated fish is released into the other cage net.
[0050] The skilled person will also understand that the processing duct are applicable here. In addition to, or instead of, a chemical treatment, the fish may be measured, weighted, sorted into different cage nets or other tanks, etc. The skilled person will be able to identify the relevant equipment for such operations and to make addition to the embodiment described herein without departing from the invention as defined in the claims. If the processing duct comprises separation means based on parameters such as weight, length etc. of the fish, more than one fish outlet tubes may be provided for leading and releasing the sort fish into different cage nets, tanks, etc.
[0051] The processing duct may also comprise equipment for removing parasites at the outside of the fish, such as salmon louse by spraying with water or an aqueous solution. One possibility is here to include sensor equipment for identifying parasites to use spraying equipment targeting the individual parasite for removing them from the fish without damaging the fish. The skilled person will also understand that separator plates for aligning the fish may be an advantage for such spraying to reduce the sideways movement of the fish, movement that may do the spraying less efficient or less targeted to the parasite.
[0052] The present method may also be used for medical treatment, such as individual injections in the fish and/or for tagging of the fish by injecting an identifiable tag, such as a RFID. Methods for injections of smolt is known in the art. Such injections will presumable require using alignment devices so that the fish is introduced individually into injection section(s). As soon as the fishes are aligned and individually separated from each other, they may also be weighted, scanned, sorted etc.
[0053] One other possible use for the present invention may be for taking up fish to be slaughtered. The above-described processing duct may then be substituted by equipment for slaughtering of the fish, or the fish outlet tube 24 may lead the fish directly into a plant for slaughtering of the fish, or into a tank for transport of the fish to be slaughtered.
[0054] A collection net 29 shaped as a half funnel having its smallest opening towards the lower end or the duct 14 may be connected to the lower end of the duct 14 , and opening into the water inside the cage net. The collection net 29 will assist in leading the fish from the cage net into the funnel 14 . Collection net floaters 31 are arranged at the sides of the collection net to keep the sides of the collection net floating at the surface as illustrated in the figures.
[0055] The duct 14 is preferably pivotally arranged on the float 4 , so that it may be placed onto the deck 5 for transport. The duct 14 may also be divided into separate sections that may be separated for transport, or may be telescopically adjustable for transport. The fish outlet tube is also preferably arranged so that it may be taken onboard the float for transport. The skilled person will also understand that the tube 10 is winded up and out of the water for transport.
[0056] The skilled person will understand that the present device for taking up fish may be arranged on a separate vessel as illustrated and described above, or the device or parts thereof may be arranged at the cage net floater.
[0057] Even though the invention has been described with reference to a fish farm and cage nets, the skilled person will understand that the present method and device may be used for other purposes, such as taking up fish for treatment, control, scientific purposes etc. in any relevant body or water. Accordingly, it is also assumed that the present device and method may be of use for taking up fish in the wild during migration of fish where fish density normally is high, or for catching fish that has escaped from a fish farm e.g. due to damage or breakdown of a cage net or the like.
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A method for taking fish up from a body of water comprising the steps of providing a duct ( 14 ) having a lower open end below the water surface and an upper open end arranged at a floating working platform ( 5 ) above sea level; introducing water into the duct ( 14 ) from the upper open end to give a water stream from the upper open end of the duct to the lower open end of the duct; and allowing the fish to swim up in the duct against the water stream therein. The incoming water is directed to flow into the duct, and the fish is separated from the flowing by means of a grating ( 16 ) inclining upwards from the top end of the duct to a separation plate ( 17 ) arranged above the water level in the duct. A device for taking up fish, using the mentioned method is also described.
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CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a divisional application of U.S. patent application Ser. No. 11/381,411, filed May 3, 2006 now U.S. Pat. No. 7,240,612.
BACKGROUND OF THE INVENTION
The present invention is directed to an improved strapping machine. More particularly, the present invention is directed to a strapping machine having an improvements in conveyance and handling of loads in the machine and access to internal systems for maintenance.
Strapping machines are in widespread use for securing straps around loads. One type of known strapper includes a strapping head and drive mechanism mounted within a frame. A chute is mounted to the frame, through which the strapping material is fed.
In a typical stationary strapper, the chute is mounted at about a work surface, and the strapping head is mounted to a horizontal portion of the chute, below the work surface. The drive mechanism is also mounted below the work surface, near to the strapping head. The drive mechanism “pulls” or feeds strap material from a source, such as dispenser into the machine. The drive mechanism urges or feeds the strap through the strapping head, into and around the chute, until the strap material returns to the strapping head. The drive mechanism also retracts the strap material to tension the strap around the load.
It has also been found that it is often necessary to access the strapping head (and more specifically the weld head) by removing portions of the work surface. This may be necessary to dislodge misfed strap, to clear the strapping head or weld head, or for general maintenance or repair of the machine. Quite often, it is necessary to access the strap path (by moving the strap chute) at the weld head.
Often strapping machines are positioned or located in a product line such that the working surface of the strapper is at a higher elevation than a conventional work surface. In such instances, it can be difficult to open the various panels and the like to permit access to the internal portions of the machine. This is particularly the case with moving or removing the working surfaces of the strapper to access the strapping head and the feed/retraction mechanism.
Many such machines are employed in processes that maximize the use of fully automated operation. To this end, machines are configured for automated in-feed and out-feed, such that a load (to be strapped) is automatically fed into the machine by an in-feed conveyor, the strapping process is carried out, and the strapped load is automatically fed out of the machine by an out-feed conveyor. However, there may be times that loads are physically too small to be moved into the strapping area by known conveyors, or other times that loads come into the strapping area that are askew and require squaring or straightening, or may need to be compressed before being strapped.
Accordingly there is a need for an improved strapping machine that facilitates package or load handling and strapping. Desirably, such a machine facilitates the handling and strapping of loads that may otherwise be difficult to handle. More desirably, such a machine eases movement or removal of the work surfaces to access the internal portions of the machine.
BRIEF SUMMARY OF THE INVENTION
A strapping machine is configured to feed a strapping material around a load, position, tension and seal the strapping material around the load. The machine includes a work surface for supporting the load. At least a portion of the work surface is upwardly pivotal.
A conveyor is mounted within the work surface that has a friction belt drive. The conveyor includes a pair of end rollers that define a plane and the conveyor rollers are engaged by the belt along the plane. Intermediate rollers are disposed between the end rollers. A tension roller maintains tension in the belt. The conveyor is configured so that a load present on the conveyor increases a force between the conveyor rollers and the drive belt to drive the conveyor.
A strap chute carries the strapping material around the load and releases strap from the strap chute. A load compression assembly is mounted to the frame and disposed above the work surface. The compression assembly includes a reciprocating gate that moves toward the work surface to contact and compress the load prior to conveying the strap around the load. The gate is actuated by a rod-type cylinder operably connected to the machine frame and to an uppermost point on the gate. The cylinder and rod are below the uppermost point of the gate when the gate is in the feed or the compressed state. Preferably, the cylinder is enclosed within the arch enclosure of the chute. The gate can be formed from a transparent or translucent material to permit viewing the load through the gate.
The conveyor roller closest to the strap chute has end portions and a middle portion that has a smaller diameter than the end portions. The end and middle portions are fitted together to rotate as a unitary element. The roller includes a pair of spindles, one in each end portion extending toward the middle portion. The spindles are rotatable independent of their respective end portions and independent of one another.
The machine includes a side squaring assembly that aligns the load in the direction transverse to the load direction. The side squaring assembly includes a pair of side plates that substantially simultaneously move toward one another to square the load on the conveyor. The side squaring assembly includes a drive having a pair of substantially mirror image cylinders
The side plates can each include a forward squaring plate mounted to the side plate transverse to the side plate. The forward squaring plate squares the load in the machine direction. The machine can also include a longitudinal squaring drive having a pair of rotating engaging elements for squaring the load in a longitudinal direction. Load contact elements are loosely mounted to the rotating engaging elements such that the load is driven forward by the contact elements when there is low resistance to movement and when the load resists movement the contact elements stop and the rotating engaging elements rotate freely of the stopped contact elements.
A strap guide extends between the pre-feed assembly and the feed assembly and includes a fixed portion and a movable portion. The movable portion moves toward and away from the fixed portion to form a guide path that is opened to access the guide path.
An enclosure is mounted to the machine frame below the work surface. The sealing head and the feed assembly are located within the enclosure and are accessed by an interlocked, openable access panel and an interlocked access door on the panel.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein:
FIG. 1 is a perspective view of a strapping machine illustrating in phantom a work surface lift system of the present invention;
FIG. 2 is a partial perspective view of the underside of the work surface illustrating the lift lever and arm;
FIG. 3 is view of the lever and arm showing the arm engaging the work surface;
FIG. 4 is a perspective view of the strapping machine illustrating in phantom a load weight engaging conveyor system of the present invention;
FIG. 5 is an enlarged, partial perspective view of the weight engaging conveyor system with a single roller in place;
FIG. 6 is a top perspective view of the conveyor system with the rollers removed for ease of illustration;
FIG. 7 is an exploded view of the conveyor system again, with the rollers removed for ease of illustration;
FIG. 8 is a bottom view of the drive assembly for the conveyor system;
FIG. 9 is an exploded view of the conveyor system, rollers and support elements;
FIG. 10 is a perspective view of the strapping machine illustrating a load compression system of the present invention;
FIG. 11 is a partial perspective view of the load compression system frame and support assembly illustrating the cylinder mounting arrangement;
FIG. 12 is a partial view of a corner of the compression screen showing the cylinder mount;
FIG. 13 is a illustrates an outside wall of the compression mount frame;
FIG. 14 is an enlarged view of the cylinder mount;
FIG. 15 is a view of the compression mount cylinder in the retracted state;
FIG. 16 is an enlarged view of a section of the compression assembly;
FIG. 17 is a perspective view of the strapping machine illustrating a load side squaring system of the present invention;
FIG. 18 is a perspective view of the squaring system illustrating the squaring plates and machine rollers;
FIG. 19 is a bottom perspective view of the squaring system illustrating the drive system;
FIG. 20 is a top perspective view of the system with the rollers removed for ease of illustration;
FIG. 21 is a perspective view of the strapping machine illustrating a load stack friction drive system of the present invention;
FIG. 22 is a perspective view of the system as it is on the machine rollers;
FIG. 23 is a front view of the load stack friction drive system;
FIG. 24 is a perspective view of the strapping machine illustrating a conveyor nose roller of the present invention;
FIG. 25 is a perspective view of the nose roller positioned in the conveyor, adjacent to the area at the strapping head;
FIG. 26 is an enlarged partial view of the nose roller;
FIG. 27 is a perspective view of the nose roller removed from the conveyor system;
FIG. 28 is an exploded view of the nose roller;
FIG. 29 is a perspective view of the strapping machine illustrating in phantom a strap guide and opening system of the present invention;
FIG. 30 is a partial view of the strap guide and opening system with the guide in the open state;
FIG. 31 is a view similar to that of FIG. 30 with the guide in the closed state;
FIG. 32 is a perspective view of the strapping machine illustrating in phantom a drop down front enclosure panel;
FIG. 33 is a partial view of the drop down panel;
FIG. 34 is a partial view of the frame sides showing the hinges and interlocks;
FIG. 35 is another partial view illustrating the panel interlock;
FIG. 36 is a view of the panel side;
FIG. 37 shows, in phantom, the slide action of the access door within the drop down panel;
FIG. 38 illustrates the access to and action of the lift arm;
FIG. 39 illustrates the interlock on the access door;
FIG. 40 illustrates the door residing in the drop down panel in phantom; and
FIG. 41 illustrates the rear of the access door as it resides within the panel.
DETAILED DESCRIPTION OF THE INVENTION
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated.
It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein.
Referring to the figures and in particular FIG. 1 , there is shown generally a strapping machine 10 embodying the principles of the present invention. The strapping machine 10 includes, generally, a frame 12 , a strap chute 14 , a feed assembly 16 and a weld head 18 (both shown briefly in FIG. 25 ). A controller 20 provides automatic operation and control of the strapper 10 . A table top or work surface 22 is disposed on the strapper 10 at the bottom of the chute 14 . The work surface 22 is configured as a conveyor 24 and will be discussed in more detail herein. A strap supply or dispenser 26 supplies strapping material S to the feed assembly 16 and weld head 18 .
The work surface 22 , again as will be discussed below, is configured having in-feed and out-feed conveyors 28 , 30 that are formed as part of the work surface 22 and pivot upwardly and outwardly (relative to the strap chute 14 ) to provide access to the internal components, e.g., the feed assembly 16 and the weld head 18 . This is often necessary to conduct maintenance or inspection of these areas. It will also be appreciated that the work surface 22 is often at a height that is greater than a conventional work surface height. That is, the work surface 22 is positioned at a height that is complementary to the other aspects of whatever operation the strapper 10 is part of. As such, the work surface 22 could be at a height that makes it difficult to lift the conveyors 28 , 30 to access the internal components.
The present strapping machine 10 includes a novel work surface lift system 32 to facilitate lifting the conveyors 28 , 30 to raise and hold them in an open condition. As seen in FIGS. 2 and 3 , the lift system 32 includes an arm 34 that is pivotally mounted to the frame at an arm pivot 36 . The arm 34 includes a lever portion 38 that extends from an end 40 of the arm 34 , about transverse thereto. The lever portion 38 has a roller 42 mounted at a free end 44 that engages a lip edge 46 of the conveyor 28 , 30 . The pivot 36 is defined at the juncture 50 of the lever portion 38 (at about the elbow), at which the arm 34 is mounted to the frame 12 . A hand grip portion 52 is mounted to an opposite end 54 of the arm 34 (opposite of the lever portion 38 ) and is used to manually operate the arm 34 . The grip 52 (arm) is accessed from a front access door 56 in the access panel 58 of the machine enclosure 60 for ease of use.
The hand grip 52 is pulled toward the front of the machine 10 (toward the operator). The mechanical advantage afforded by the longer travel of the arm 34 facilitates lifting of the work surface 22 (conveyor 28 or 30 ) by the shorter lever portion 38 . A cylinder 62 serves to maintain the arm 34 in the engaged (lifted) position and a spring 64 aids in providing the force to return the surface 22 to the closed condition. When in the open state, the lever roller 42 engages a notch 66 formed in the lip edge 46 of the conveyor 28 , 30 to prevent the lever roller 42 from slipping along the lip 46 (to inadvertently close).
A load weight engaging conveyor drive system 68 is illustrated in FIGS. 4-9 . The system 68 is configured so that the conveyor rollers 70 are driven as the weight on the rollers 70 (the conveyor section) increases. The drive system 68 includes a motor 72 , preferably a direct current (DC) driven motor that drives a drive belt 74 . The belt 74 is maintained in a generally planar state (relative to the conveyor 28 , 30 and rollers 70 ) by a pair of end rollers 76 that define a plane P 76 at about their peripheries and intermediate rollers 78 that are also, at their peripheries, about at the end roller plane P 76 .
The belt 74 encircles the rollers 76 , 78 and a drive roller 80 on the motor 72 . A tension roller 82 is mounted to a pivoting arm 84 that is biased (by a spring 86 ) to maintain tension in the belt 74 . The motor 72 and the rollers (the end 76 and intermediate 78 rollers) are mounted to a carriage or frame 88 that is mounted to the pivoting work surface 22 (conveyor sections 28 , 30 ) to facilitate maintenance on or removal of the drive system 68 .
The frame 88 includes slots 90 in which the conveyor roller ends (spindles 92 ) reside during operation. A cover 89 is configured and positioned to prevent the conveyor roller spindles 92 from being displaced when the work surfaces 22 , 24 are pivoted upwardly. In present embodiment, cover 89 has slots 91 in which the roller spindles may also reside. The roller spindles 92 “float” in the slots 90 , and in the present embodiment, slots 91 , so that the rollers 70 “float” on the drive belt 74 . In this manner, the normal force between the rollers 70 and the belt 74 is created by the weight of the rollers 70 combined with the load L on the belt 74 . It will be appreciated that the conveyor rollers 70 sit along a top or outer surface 94 of the belt 74 while the end and intermediate rollers 76 , 78 (those that are part of the drive 68 ), sit along a bottom or inner surface 96 of the belt 74 . In addition, the location at which the conveyor rollers 70 sit on the belt 74 is between adjacent end/intermediate rollers 76 , 78 and, likewise, the end/intermediate rollers 76 , 78 support the belt 74 between adjacent conveyor rollers 70 . In this manner, the conveyor rollers 70 are in effect cradled by the belt 74 between drive rollers 76 , 78 . A bracket 79 is attached to the conveyor frame 88 with the belt 74 positioned between the bracket 79 and the frame 88 . The bracket 79 is in turn mounted to the conveyor cover 89 .
FIGS. 10-16 illustrates a load compression assembly 98 . Load compression is provided by a compression gate 100 that is actuated by a cylinder 102 , located on a side of the gate 100 . The compression assembly 98 is configured to compress the load L prior to strap S being positioned and tensioned around the load. This reduces the amount of strap that has to be fed out and in turn retracted to strap the load. It also provides a pre-load on the load which in turn reduces the amount of work that has to be done by the feed and strapping (weld) heads 16 , 18 .
As set forth above, compression gate drive is provided by a rod-type cylinder 102 , located on a side of the gate 100 . The cylinder 102 is mounted within the chute arch enclosure 104 , which is the frame structure that houses the strap chute 14 . In this manner, one end 106 of the cylinder 102 is mounted to the frame 12 at about the work surface elevation 22 and the other end 108 (the rod) is mounted to the gate 100 . Accordingly, no additional space is required, nor addition structure required to house the gate 100 and cylinder 102 above the topmost extension of the gate 100 . Advantageously, this reduces the overall head space required for the compression assembly 98 , and when the gate 100 is in the lowered position (e.g., the compression position), the cylinders 102 are fully retracted and thus the overall machine 10 height is less than known machines (that have overhead mounted cylinders).
FIGS. 17-20 illustrate a side squaring system 110 that is configured to square the lateral sides of a load L and to restrain the forward movement of the load (which in effect squares the longitudinal (front) edges of the load. The squaring system 110 includes a pair of opposed laterally moving side squaring plates 112 . In the illustrated embodiment, both side plates 112 have forward edge squaring plates 114 , however, it will be recognized that the forward squaring plate 114 can be present on only one of the side plates 112 and will function effectively.
The side plates 112 are mounted to a drive system 116 that is mounted to the machine 10 below the rollers 70 . In this manner, the drive mechanism 116 does not interfere with the operation of the strapper 10 . It will also be appreciated that the side squaring system 110 is mounted upstream (forward) of the strap chute 14 , again so that it does not interfere with the operation of the strapper 10 .
The drive system 116 is configured to move laterally (sideways) to square the sides of the load L. For example, when strapping magazines, the load can be moved up to the side squaring system 110 and the side plates 112 moved inward so that the leading ends (edges) of the magazines square up to the forward squaring plates 114 . The side plates 112 can then move further inward to square up the side edges of the magazines. Once the forward and side edges are squared, the side plates 112 can be retracted and the load can be conveyed forward into the strap chute 14 .
The drive system 116 is configured to move the side plates 112 simultaneously toward and away from each other so that squaring is carried out relatively symmetrically. Accordingly, the drive 116 includes a pair of rod-type cylinders 118 mounted in mirror image relation to one another with the rod ends 120 mounted to the plates 112 (to laterally move the plates 112 ) and the cylinder ends 122 fixed within the assembly carriage 124 . The rod ends 120 are mounted to bearing plates 126 that traverse along rod bearings 128 to provide smooth movement of the plates 112 . As seen in FIGS. 18 and 20 , the side plates 112 are mounted to the bearing plates 126 by supports 129 that are positioned and extend up from between rollers 70 so as to prevent any interference.
FIGS. 21-23 illustrate a longitudinal squaring drive 130 that functions with the forward edge squaring plates 114 . The forward squaring drive 130 includes a pair of opposing, rotating central elements 132 and a plurality of loosely mounted rotating rings 134 . The drive element 132 and rings 134 are formed from a resilient, low friction material, such as neoprene or the like. The rings 134 are loosely mounted or fitted to their respective drive elements 132 so that the rings 134 will rotate when they are in contact with the central drive element 132 . However, when the friction or contact force between the rings 134 and the load L or material being driven is too great, the rings 134 will not rotate. Rather the friction between the rings 134 and the load L is too great to permit the rings 134 to move. Accordingly, when, for example, a load of material (such as the exemplary magazines) is introduced to the forward squaring drive 130 , the magazines that may be out of longitudinal (forward to rearward) alignment contact the rotating rings 134 and are driven into the forward squaring plates 114 . When, however, the magazines contact the forward squaring plates 114 , the friction that results at the rings 134 /magazine interface is too great for the rings /drive element 134 / 132 to overcome, and the rings 134 stop rotating relative to the drive elements 132 .
FIGS. 24-28 illustrate a necked-down roller 136 . It will be appreciated that the roller or those rollers closest to the strap chute often cannot be full length rollers due to interferences or, as illustrated, plates P that may overlie a portion of the chute at about the strapping head. Because these rollers are not full length (that is, they do not fully extend across the conveyor), they are not driven rollers. Instead, these rollers are idler or passive rollers that only provide a bearing surface across which the package can move. This can be problematic, especially with smaller items or packages that are not sufficiently long to extend from one driven roller (on the infeed side), across the chute area, and on to the next driven roller (on the outfeed side).
The present necked-down roller 136 overcomes these drawbacks by providing a roller having a smaller diameter portion at about the middle of the roller 138 and larger outer sections 140 (that are the same diameter as the other rollers 70 ) that is driven together with the remaining rollers 70 on the conveyor 28 , 30 . In this manner, accommodation is made for the interference (plate 142 ) while still maintaining the roller outer sections 140 at the same diameter so as to properly convey smaller loads into the strapper chute 14 area.
The roller 136 outer roller sections 140 are the same diameter as the other rollers 70 of the conveyor 28 . 30 . The middle, necked-down transition section 138 bridges the two outer sections 140 . A spindle 144 extends through each of the outer roller sections 140 from the end 146 of the outer section 140 to a bearing 148 at the necked-down transition 138 . The spindles 144 are held within the roller sections 138 , 140 by a plurality of bearings 148 , 150 , which as illustrated, can include inner and outer bearings on each of the outer sections 140 . Accordingly, the outer sections 140 can rotate while the spindles 144 remain fixed with the ends 152 residing within the conveyor drive frame slots 90 (see FIG. 5 ). The smaller diameter transition section 138 is press-fit to the outer sections 140 so that the entirety of the roller 136 functions as a single element with the stationary spindles 144 .
FIGS. 29-31 illustrate a strap guide and opening system 154 that is configured for a machine 10 such as the elevated work surface 22 machine discussed above. The opening strap guide 154 provides a pathway (indicated generally at 156 ) through the machine 10 from the supply 26 to the strapping head (or the feed system 16 ) so that the strap S can traverse in a controlled and unobstructed manner. Such a guide 154 is important to prevent the strap from twisting, kinking or otherwise jamming as it is fed from the strap supply 26 .
It is also important to be able to access the guide 154 so that strap S can be removed as needed (e.g., sections of jammed strap material). Accordingly, the present strapper guide 154 has a drop down access section 158 that extends from a pre-feed assembly 160 (which is a driven element that is located at the inlet to the machine 10 ) to the feed head 16 . The guide 154 is formed from an upper guide portion 162 that remains stationary and the lower movable guide portion 158 . The lower guide portion 158 is actuated (moved) by movement of a handle 164 and moves along a pair of pins 166 that are fixed to the machine 10 . The lower guide 158 has arcuate slots 168 along which the guide 158 moves between the open position ( FIG. 30 ) and the closed position ( FIG. 31 ). The arcuate slot 168 shape (as opposed to linear, e.g., vertical shape) provides for lateral movement of the lower guide 158 away from the pre-feed assembly 160 (as the guide 154 is opened) to provide better access in and around the pre-feed 160 area. And in that the strap S is fed about a roller 170 at the feed head 16 (exiting the guide 154 ), the movement of the lower guide 158 away from the roller 170 at the feed head 16 entrance does not adversely effect strap moving along the strap path 156 .
FIGS. 32-41 are a series of illustrations showing the front enclosure 60 , the enclosure access panel 58 and the access panel door 56 and the interlocks 172 , 174 , respectively, for the panel 58 and door 56 . As seen in FIG. 32 , the enclosure panel 58 (which includes the door 56 ) is mounted to the machine frame 12 by hinges 176 to allow the panel to pivot downwardly from the frame 12 to provide complete frontal access to the machine enclosure 60 . The panel 58 includes pins 178 that extend outwardly from the lower sides of the panel 58 that are received in hinge sleeves 180 in the frame 12 . The panel 58 includes interlocks 172 on the frame 12 ( FIG. 34 ) and the panel 58 ( FIG. 36 ) that isolate power to the machine 10 when the interlock elements 172 are disengaged from one another.
Likewise, the access door 56 , which is a two-piece sliding door that slides within a track 173 in the panel 58 , also includes interlocks 174 on the door 56 ( FIG. 39 ) and in the door frame 182 , which is within the enclosure panel 58 ( FIG. 35 ) that isolate power to the machine 10 when the interlock elements 174 are disengaged from one another. It will be appreciated that both the lift arm 34 and the guide opening handle 164 are accessible from either the open access door 56 or the lowered enclosure panel 58 .
All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically done so within the text of this disclosure.
In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover all such modifications as fall within the scope of the claims.
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A strapping machine feeds strapping material around a load, positions, tensions and seals the material around the load. The machine includes a work surface, a portion of which is upwardly pivotal. A conveyor mounted within the work surface has a friction belt drive. The conveyor roller closest to the strap chute has a middle portion that has a smaller diameter than the end portions. The middle portions are fitted together to rotate as a unitary element. A load compression assembly is mounted at the strap chute. A side squaring assembly aligns the load in the direction transverse to the load direction. A strap guide extends between a pre-feed assembly and the feed assembly and includes a fixed portion and a movable portion forming a guide path that is opened to access the guide path. An interlocked enclosure is mounted to the machine frame below the work surface to access the sealing head and the feed assembly.
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This is a continuation of application Ser. No. 782,339, filed Mar. 29, 1977, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to apparatus for severing webs or strips, especially webs or strips which consist of flexible material, and more particularly to improvements in apparatus which can be used with advantage for subdivision of webs of exposed and developed photographic material into discrete prints or groups of prints. Still more particularly, the invention relates to improvements in apparatus for severing and stacking prints or analogous sections of flexible web-like material.
Webs of exposed and developed photographic prints are customarily severed in an apparatus wherein the web is transported stepwise to place successive frame lines between neighboring prints into register with the mobile knife of a severing device. The web is held at a standstill while the mobile knife performs a working stroke to separate the foremost print from the next-following print or prints. The freshly separated prints are caused or allowed to descend into a collecting receptacle. As a rule, a first group of advancing rolls draws the web off a reel on which the web is stored in convoluted form, and a second group of advancing rolls is located immediately downstream of the severing station. The rolls of the second group are set in motion when the mobile knife of the severing device completes a working stroke to thereby advance the freshly severed print into register with the collecting receptacle. Thus, the rolls of the second group engage and support the foremost print of the web prior, during and subsequent to separation from the next-following print or prints. The prints tend to curl or flex because they are separated from a web which is normally stored in convoluted condition, and such tendency to curl prevents accurate stacking of severed prints in the collecting receptacle. The absence of accurate stacking prevents or interferes with automatic processing of prints which accumulate in the receptacle, e.g., with automatic transport to an assembly station where all prints belonging to a customer are introduced into an envelope or box, together with the corresponding exposed and developed film or film sections, for shipment to the dealer or directly to the customer.
Another drawback of presently known severing and stacking apparatus is that they cannot discriminate between prints and other sections of webs of exposed and developed photographic paper, e.g., between the prints and the leaders or trailing ends of the webs. Each print is provided with a marker (e.g., an indicium at the rear side thereof) which is detected by a scanning device, and such detection serves to arrest the web in an optimum position for separation of the foremost print from the next-following print or prints. The leaders and trailing ends of webs are not formed with markers and they are often much longer than the prints. Indiscriminate mixing of such leaders and trailing ends with satisfactory prints further interferes with orderly removal of prints from the collecting receptacle and with predictable processing of removed commodities. The relatively long leaders and/or trailing ends must be removed by hand. Relatively long sections of web material need not necessarily be located at the front or rear end of a web; thus, it can happen that useless sections of photographic paper are located midway between the ends of a web if two or more webs are spliced together end-to-end to form a composite web of substantial length.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved apparatus for subdividing webs or strips of photographic paper or the like into sections (prints) of desired length and for automatically stacking satisfactory sections on top of each other in such a way that each upper section is in accurate register with the section therebelow.
Another object of the invention is to provide the apparatus with novel and improved means for automatically segregating unsatisfactory sections (especially sections which are too long) from satisfactory sections.
A further object of the invention is to provide the apparatus with novel and improved means for manipulating successively severed sections of a web immediately downstream of the severing station.
An additional object of the invention is to provide an apparatus which is capable of automatically accumulating successively severed satisfactory sections of a web or the like into a stack wherein the sections are arrayed in such a way that they can be readily manipulated e.g., transported, inserted, counted, etc.) by automatic devices.
The invention is embodied in an apparatus for subdividing a web into discrete sections of predetermined length, particularly for subdividing an exposed and developed strip of photographic material into prints. The apparatus comprises means for advancing a web in a predetermined direction along a predetermined path which is preferably horizontal or nearly horizontal, severing means adjacent a first portion of the path and being operable to cut transversely across the web and to thus separate the foremost section of the web, preferably during each interval of idleness of the advancing means, stacking means including a platform or the like located at a level below a second portion of the path which is disposed downstream of the first portion, as considered in the direction of advancement of the web, and means for transferring successive sections from the second portion of the path onto the stacking means.
The transferring means preferably comprises two discrete depositing devices which flank the second portion of the path and each of which includes at least one wing, vane or an analogous carrier movable between a first position in which the carriers support a section in the second portion of the path and at least one second position in which the section is free to descend or is postively transferred onto the stacking means. The carriers are preferably turnable (either indexible in a single direction or rotatable back and forth) between their first and second positions.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a fragmentary partly schematic perspective view of an apparatus which embodies one form of the invention; and
FIG. 2 illustrates a portion of a modified apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown an apparatus for severing and stacking discrete prints of photographic paper. The apparatus comprises a pair of coaxial advancing rolls 1 which are mounted on a shaft 1a and are intermittently driven to advance the leader of a web or strip of photographic paper (not shown) in the direction indicated by arrow A. The rolls 1 are located immediately downstream of a severing station including a mobile knife 10 and a stationary knife (not shown). When the knife 10 is to perform a working stroke (downwardly, as viewed in FIG. 1), the advancing rolls 1 are at a standstill and engage the rear portion of the foremost print which is about to be separated from the next-following print. When the knife 10 completes a working stroke and returns to the retracted position of FIG. 1, the rolls 1 are set in motion and advance the freshly separated print to a level above a stacking platform 6 including two coplanar panels 7 which are mounted on turnable shafts 8 and normally assume the operative positions shown in FIG. 1. When the platform 6 accumulates a stack of prints (preferably a group or set of prints belonging to a customer), the panels 7 are pivoted in opposite directions (as indicated by the arrows 7a) to allow the accumulated stack to descent by gravity onto a conveyor or into a receptacle therebelow (not shown). The panels 7 thereupon return to the illustrated operative positions so that the platform 6 can begin with the accumulation of a fresh stack of superimposed prints.
In order to insure an accurately reproducible forward transport of the web and of discrete prints, the advancing rolls 1 preferably cooperate with advancing rolls 1' which are mounted on a shaft 1a'. The shaft 1a' is biased downwardly toward the shaft 1a so that the peripheral surfaces of upper rolls 1' tend to engage the peripheral surfaces of the rolls 1 therebelow, i.e., the print in the horizontal path between the upper and lower rolls 1' and 1 can be transported without any or with negligible slippage.
The apparatus further comrpises a control unit or synchronizing unit 11 which transmits signals to intermittently operated drive means 12 for the shaft 1a and to reversible drive means 13 for the shafts 8. The two shafts 8 are preferably coupled to each other by a gear train or the like so that the right-hand shaft 8 turns counterclockwise when the left-hand shaft 8 turns clockwise, and vice versa. The control unit 11 receives signals from a detector (not shown) which monitors the rear sides of prints and causes the unit 11 to arrest the drive means 12 whenever the frame line between the foremost print and the next-following print is in exact register with the cutting edge of the mobile knife 10. The unit 11 thereupon starts the drive means 12 with a preselected delay which suffices to allow the knife 10 to return to the raised position of FIG. 1; the drive 12 causes the freshly severed print to advance beyond the nip of the rolls 1 and 1' and to come to rest on the adjacent preferably horizontal wings of carriers 3 of two rotary depositing or transferring devices 2 which flank the path for the prints at a level above the stacking platform 6. The path for the web and prints of photographic paper is preferably horizontal or nearly horizontal.
The wings or carriers 3 of the depositing devices 2 extend radially from the respective cylindrical hubs 4 which are mounted on and rotatable (indexible) by supporting shaft 2a. The left-hand shaft 2a of FIG. 1 receives motion from a drive means 14 which is controlled by the unit 11, and the right-hand shaft 2a is coupled to the left-hand shafts 2a by means of a gear train or the like so that the devices 2 are indexed in opposite directions, always through 90 degrees. The shortest distance between the hubs 4 equals or only negligibly exceeds the width of a print so that, when a freshly severed print enters the space between the adjacent wings 3 (denoted by the reference characters 3A), its marginal portions rest on the upper sides of the wings 3A and its longitudinally extending edge faces abut the respective hubs 4. Such hubs can be said to constitute a means for orienting the prints prior to transfer onto the platform 6. When the rolls 1 are arrested, i.e., when a freshly severed print has been advanced beyond the nip of the rolls 1 and 1' and rests solely on the wings or carriers 3A, the drive means 14 rotates the supporting shafts 2a through 90 degrees whereby the freshly severed print descends onto the panels 7 therebelow and the next-following wings 3 come to a halt in the positions previously occupied by the wings 3A. Such next-following wings 3 are then ready to support the next print and to transfer the print onto the preceding print on the panels 7 as soon as the drive means 14 receives a fresh signal from the control unit 11.
In order to prevent buckling or other deformation of the prints which rest on the wings 3 of the depositing devices 2, the apparatus preferably comprises a plate-like hold-down device 5 which is located immediately above the level of the wings 3 flanking the path for the prints above the platform 6. It will be noted that the axes of the shafts 2a are parallel to the direction indicated by the arrow A and normal to the axes of the shafts 1a and 1a'. The rear portion of the hold-down device 5 preferably extends rearwardly into and beyond the space between the rolls 1 and 1' and all the way to the severing station. This insures that the leader of the next-following print readily finds its way into the path below the hold-down device 5 when the rearmost advancing rolls (not shown in FIG. 1 but preferably corresponding to the rolls 1 and 1') are set in motion to draw the web off a supply reel or the like, not shown. The control unit 11 or another control means sets the rearmost rolls in motion as soon as the knife 10 reassumes the raised position of FIG. 1 so that the foremost print of the web can advance into the nip of the rolls 1 and 1' which are then driven to move the frame line between the two foremost prints of the web into register with the knife 10.
The apparatus preferably further comprises additional or auxiliary rolls 9 and 9' which are mounted downstream of the depositing devices 2, as considered in the direction indicated by arrow A, and serve to engage and remove the leaders and trailing ends of successive webs, i.e., those sections of the webs which do not carry markers and do not constitute prints. As a rule, the leaders and trailing ends of the webs are longer than the prints so that the front portions af such relatively long web sections are held in the nip of the rolls 9 and 9' and cannot descend onto the platform 6. The shat 9a for the rolls 9 can be driven at all times so that these rolls automatically advance the relatively long web sections beyond the platform 6 and allow or cause such long web sections to descend into a collecting receptacle, not shown.
The operation:
The rolls 1 and the preceding or rearmost rolls are set in motion in response to a signal from the control unit 11 so that they advance the web from the reel (not shown) and all the way to a position in which the frame line between the two foremost prints (or the front edge of the foremost print of a series of prints) is located in the path of movement of the cutting edge of the knife 10. As mentioned above, the control unit 11 receives signals from a detector which monitors the markers associated with successive prints. Stoppage of the rolls 1 and 1' is immediately followed by actuation of the severing means, i.e., the knife 10 descends and severs the web transversely across the foremost frame line, in front of the foremost print or behind the rearmost print of a series, as the case may be. When the knife 10 returns to the raised position of FIG. 1, the rolls 1 are set in motion again to advance the freshly separated print to a position above the platform 6 whereby such print comes to rest on the wings 3A and is held against buckling or other deformation by the underside of the hold-down device 5. The hubs 4 of the depositing devices 2 insure that the print on the wings 3A is in exact register with the print therebelow (on the panels 7) because the shortest distance between the hubs 4 immediately above the wings 3A equals or negligibly exceeds the width of a print.
The shafts 2a are set in motion as soon as the separated foremost print comes to rest solely on the wings 3A, and the devices 2 turn through 90 degrees (in opposite directions) to transfer the print onto the panels 7 or onto the uppermost print on the platform 6. At the same time, the next wings 3 assume the positions previously occupied by the wings 3A, and the control unit 11 starts the rearmost rolls and the rolls 1 to advance the next (still unseparated) print beyond the severing station. The web is then arrested and the knife 10 performs a workings stroke to sever the web across the frame line between the two foremost prints.
The panels 7 are pivoted to discharge the accumulated stack of prints when the aforementioned detector or an additional detector transmits a signal which causes the control unit 11 to actuate the reversible drive means 14. Such signal is produced in response to detection of a marker or indicium which designates the last print of a series, e.g., the last print of a customer order or the last print of the web.
Any relatively long sections of the web, i.e., those sections which are long enough to enter the nip of the rolls 9 and 9', cannot descend onto the platform 6; they are automatically entrained by the rolls 9 and 9' to enter the aforementioned receptacle or to be desposited onto a conveyor which transports the relatively long web sections to a waste collector or to another destination.
An advantage of indexible depositing devices 2 is that successive prints are more or less positively transferred onto the panels 7 or onto the uppermost print of a stack on the platform 6, and also that the next wings 3 automatically assume optimum positions with respect to the path of prints downstream of the advancing rolls 1 as soon as the transfer of the preceding print onto the stacking platform 6 is completed.
The distance between the nips of the rolls 1, 1' and the nips of the rolls 9, 9' exceeds the length of a satisfactory print so that the rolls 9, 9' cannot engage and entrain any satisfactory prints; this results in automatic segregation of unsatisfactory web sections from satisfactory web sections (prints).
FIG. 2 shows a portion of a modified apparatus wherein each of the two depositing or transferring devices 102 (only one shown) comprises a single carrier or wing 103A and an upwardly extending orienting or aligning member 104. A portion of a print which rests on the wing 103A is shown at 16. The supporting shaft 102a of the illustrated depositing device 102 is turnable back and forth through 90 degrees in directions indicated by the arrow 117. When a print 16 rests solely on the wings 103A, the devices 102 are caused to turn through 90 degrees (the illustrated device 102 turns anticlockwise, as viewed in FIG. 2) to deposit the print 16 onto the panels (not shown) or onto the uppermost print of the stack therebelow. The respective drive means thereupon rotates the devices 102 in the opposite directions so that the wings 103A reassume their first or operative positions. The marginal portions of a print 16 which rests on the wings 103A abut against or are close to the adjacent sides of the lower portions of the respective orienting members 104. This insures accurate stacking of prints 16 on the platform.
Depositing devices of the type shown in FIG. 2 can be used in relatively slow apparatus wherein the intervals between successive severing operations are long enough to allow for rotation of each shaft 102a in opposite directions.
It is further clear that each of the devices 2 of FIG. 1 can be provided with a single carrier or with two, three, five or more carriers; the respective drive means 13 is then adjusted to index the shafts 2a through 360°, 180°, 120°, 72°, etc.
Still further, the hubs 4 need not serve for lateral guidance or orientation of prints on the wings 3A. For example, the apparatus of FIG. 1 may be provided with two sets of pushers which flank the sides of a print on the wings 3A and perform a working stroke before the shafts 2a are rotated so as to insure that the print is properly centered on the wings 3A prior to descending onto the platform 6 or onto the uppermost print of the stack therebelow.
It is also possible to replace the depositing devices 2 of FIG. 1 with endless belts or chains which carry outwardly extending rungs or steps on which the prints 16 come to rest. The conveyors must be mounted in such a way that their rungs or steps are nearest to each other when they are adjacent the path for a freshly separated print and that they thereupon move away from each other while transporting the print toward the platform 6 therebelow so that the rungs are disengaged from the print not later than when the latter reaches the panels 7 or the uppermost print of the stack therebelow.
An important advantage of the improved apparatus is that it can convert a web of coherent sections into a stack of sections wherein successive sections are in accurate register with each other. Another advantage of the improved apparatus is that it can automatically segregate unsatisfactory sections (i.e., the leaders and trailing ends of webs of photographic paper or the like if the satisfactory sections are discrete prints) from satisfactory sections and does not permit the unsatisfactory sections to reach the stacking zone for acceptable sections. The stacks which accumulate on the platform 6 can be readily transported and/or otherwise processed by automatic means, or are in an optimum condition for manual or automatic insertion into envelopes, boxes or other types of containers. The distance between the nips of rolls 1, 1' and 9, 9' is preferably selected in such a way that the nip of the rolls 9, 9' receives the leader of the shortest unsatisfactory section of a web, as long as such unsatisfactory section is longer than a satisfactory section.
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 and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.
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Apparatus for subdividing a web of exposed and developed photographic paper into discrete prints has advancing rolls which move the web lengthwise in stepwise fashion to place successive frame lines into register with a severing device which is thereupon actuated to sever the web in order to separate the foremost print. Such print comes to rest on the wings of two turnable depositing devices which flank the path for the prints downstream of the severing device and are thereupon operated to rotate the wings in opposite directions so as to allow the print thereon to descend onto a composite stacking platform therebelow. The depositing devices have rotary hubs or plate-like orienting members which align the print on the wings with the prints of the stack therebelow. A hold-down plate is provided above the path for the prints to maintain the marginal portions of successive freshly separated prints in contact with the wings while the wings are held in the operative positions immediately below the path for the prints. The leaders and trailing ends of the webs are longer than the prints, and such sections of the webs are caused to enter the nip of auxiliary advancing rolls which transport them forwardly so that the longer sections cannot be transferred onto the stacking platform.
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[0001] This application claims the priority benefit of Taiwan patent application number 100118141, filed on May 24, 2011.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to fasteners for joining metal plate members and more particularly, to a floating fastener, which assures locking stability, avoiding accidental disengagement between parts and accidental separation of the first plate member from the second plate member.
[0004] 2. Description of the Related Art
[0005] Screws or pins are commonly used many different products for the positioning of movable members. For example, a lock pin may be used to lock a sliding box or board member when the sliding rails of the sliding box or board member are moved relative to respective sliding grooves to a predetermined position, facilitating user's operation. In a desk computer system, industrial computer system, work station or any other equipment where movable plate members are detachably arranged together, screws or pins may also be used to lock the movable plate members together, facilitating mounting and dismounting. To facilitate detachable installation and to avoid missing component parts, floating fasteners are created.
[0006] FIGS. 9 and 10 illustrate a floating fastener according to the prior art. According to this design, the floating fastener comprises a connection member A, a locking device B consisting of a knob B 1 and a locking shank B 2 , a spring member C and a lock screw D. The lock screw D is inserted through a mounting through hole E 1 of a first plate member E and fastened to the connection member A to affix the connection member A to the first plate member E. The locking shank B 2 has a shank body B 21 upwardly inserted through a top center hole All of the connection member A, and a relatively thicker shank head B 22 located on the bottom end of the shank body B 21 for fastening to a retaining hole F 1 of a second plate member F to lock the first plate member E to the second plate member F. The spring member C is sleeved onto the shank body B 21 of the locking shank B 2 and stopped between the relatively thicker shank head B 22 and the top wall of the connection member A. When locking the first plate member E to the second plate member F, the relatively thicker shank head B 22 is directly and axially forced into engagement with the retaining hole F 1 of the second plate member F. When unlocking the first plate member E from the second plate member F, the relatively thicker shank head B 22 is directly upped upwardly away from the retaining hole F 1 of the second plate member F. This design of floating fastener is still not satisfactory in function. When the second plate member F is pulled by an external force, a shearing force may be produced, causing disconnection of the relatively thicker shank head B 22 from the retaining hole F 1 of the second plate member F. During a wiring work, or transfer or delivery of the equipment, the relatively thicker shank head B 22 may be forced away from the retaining hole F 1 of the second plate member F accidentally, leading to component or equipment damage.
[0007] Therefore, it is desirable to provide a floating fastener that eliminates the aforesaid problem.
SUMMARY OF THE INVENTION
[0008] The present invention has been accomplished under the circumstances in view. It is therefore an object of the present invention to provide a floating fastener for detachably fastening a first plate member to a second plate member, which assures locking stability, avoiding accidental disengagement between parts and accidental separation of the first plate member from the second plate member.
[0009] To achieve this and other objects of the present invention, a floating fastener comprises a connection member fastened to a first plate member with a lock screw member, a retaining member having a center retaining hole with low inside wall portions, high inside wall portions, positioning grooves and locating grooves and installed in a second plate member, a rotary locking device coupled to the connection member and having a locking shank and a shank head with longitudinal cut planes and a bottom stop flange and insertable through the retaining member, a spring member supported between the top wall of the connection member and a step around the periphery of the locking shank, a knob affixed to the top end of the locking shank and operable to bias the locking shank between a locking position and an unlocking position.
[0010] The shank head of the locking shank is forced into the center retaining hole of the retaining member at the second plate member when the longitudinal cut planes and bottom stop flange of the locking shank are respectively kept in alignment with the low inside wall portions and high inside wall portions of the retaining member. After insertion of the shank head of the locking shank into the center retaining hole of the retaining member, press the knob downwards and rotate the rotary locking device to force the arched faces and bottom stop flange of the locking shank into engagement with the respective positioning grooves and locating grooves, and therefore the second plate member is locked to the first plate member firmly, avoiding accidental disconnection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an oblique top elevation of a floating fastener in accordance with a first embodiment of the present invention.
[0012] FIG. 2 is an exploded view of the floating fastener in accordance with the first embodiment of the present invention.
[0013] FIG. 3 corresponds to FIG. 2 when viewed from another angle.
[0014] FIG. 4 is a sectional side view of the floating fastener in accordance with the first embodiment of the present invention.
[0015] FIG. 5 is a schematic sectional applied view of the first embodiment of the present invention, illustrating the floating fastener fastened to the first metal plate member before installation of the retaining member in the second plate member.
[0016] FIG. 6 corresponds to FIG. 5 , illustrating the retaining member installed in the second plate member.
[0017] FIG. 7 corresponds to FIG. 6 , illustrating the rotary locking device fastened to the retaining member at the second plate member.
[0018] FIG. 8 is a sectional view of a floating fastener in accordance with a second embodiment of the present invention.
[0019] FIG. 9 is an exploded view of a floating fastener according to the prior art.
[0020] FIG. 10 is a sectional view of the floating fastener according to the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring to FIGS. 1-5 , a floating fastener in accordance with a first embodiment of the present invention is shown comprising a connection member 1 , a rotary locking device 2 , a spring member 3 , an elastic cushion ring 31 , a lock screw member 4 and a retaining member 5 .
[0022] The connection member 1 comprises a tubular body 11 having a bottom open chamber 13 , an embossed positioning portion 12 located on the bottom edge thereof around the bottom open side of the bottom open chamber 13 , a top center hole 132 located on the top side thereof in communication with the bottom open chamber 13 , and an inner thread 131 spirally extending around an inside wall thereof in the bottom open chamber 13 .
[0023] The rotary locking device 2 comprises a knob 21 disposed above the connection member 1 , and a locking shank 22 connected to the knob 21 and inserted through the top center hole 132 and the bottom open chamber 13 of the connection member 1 . The knob 21 has a plurality of vertical tooth grooves 211 spaced around the periphery thereof, a bottom recess 213 located on the center of the bottom wall thereof and a bottom mounting hole 212 located on the center of the bottom recess 213 . The locking shank 22 has a plain shank body 221 , a top mounting portion 223 located on one end of the plain shank body 221 and riveted to the bottom mounting hole 212 of the knob 21 , a shank head 222 located on the other end of the plain shank body 221 and a step 2211 connected between the plain shank body 221 and the shank head 222 . The shank head 222 has a diameter greater than the plain shank body 221 , two longitudinal cut planes 2221 and two arched faces 2222 alternately spaced around the periphery and abutted against one another, and a bottom stop flange 2223 extending around the bottom end thereof beyond the longitudinal cut planes 2221 remote from the plain shank body 221 .
[0024] The spring member 3 is sleeved onto the locking shank 22 of the rotary locking device 2 , having its one end stopped against an inside part of the tubular body 11 of the connection member 1 around the top center hole 132 and its other end stopped against the step 2211 of the rotary locking device 2 .
[0025] The elastic cushion ring 31 is elastically compressibly set in between the bottom recess 213 of the knob 21 and the top wall of the connection member 1 around the top center hole 132 .
[0026] The lock screw member 4 comprises a screw tube 42 threaded into the inner thread 131 of the connection member 1 , a screw head 41 radially outwardly extending around the periphery of the bottom end of the screw tube 42 and an axial hole 421 surrounded by the screw tube 42 .
[0027] The retaining member 5 comprises a center retaining hole 50 cut through top and bottom sides thereof, an embossed engagement portion 51 located on the top side around the center retaining hole 50 for positioning in a mounting through hole 71 of a second late member 7 , two high inside wall portions 52 and two low inside wall portions 53 alternatively arranged around the center retaining hole 50 and connected to one another in a flush manner corresponding to the longitudinal cut planes 2221 and two arched faces 2222 of the locking shank 22 of the rotary locking device 2 , two positioning grooves 531 respectively located on the low inside wall portions 53 and two locating grooves 532 located on the bottom side of the retaining member 5 corresponding to the positioning grooves 531 .
[0028] Referring to FIGS. 4˜7 and FIGS. 2 and 3 again, during installation of the floating fastener, insert the top mounting portion 223 of the locking shank 22 upwardly in proper order through the spring member 3 , the bottom open chamber 13 and top center hole 132 of the connection member 1 and the elastic cushion ring 31 , and the riveting the top mounting portion 223 to the bottom mounting hole 212 of the knob 21 . At this time, the spring member 3 is received in the bottom open chamber 13 of the connection member 1 and stopped the inner surface of the top wall of the tubular body 11 of the connection member 1 around the top center hole 132 and the step 2211 of the rotary locking device 2 , and the elastic cushion ring 31 is accommodated in the bottom recess 213 of the knob 21 . Thereafter, attach the embossed positioning portion 12 of the connection member 1 to the top wall of a first plate member 6 around a mounting through hole 61 , and then insert the screw tube 42 of the lock screw member 4 upwardly through the mounting through hole 61 of the first plate member 6 and thread the screw tube 42 into the inner thread 131 of the connection member 1 to lock the connection member 1 to the first plate member 6 . When attaching the second plate member 7 to the first plate member 6 to keep the center retaining hole 50 of the retaining member 5 that is affixed to the mounting through hole 71 of the second plate member 7 in alignment with the mounting through hole 61 of the first plate member 6 , the spring member 3 imparts an outward pressure to the step 2211 to force the shank head 222 of the locking shank 22 into the center retaining hole 50 of the retaining member 5 at the second plate member 7 . At this time, the longitudinal cut planes 2221 and bottom stop flange 2223 of the locking shank 22 are respectively aimed at the low inside wall portions 53 and the high inside wall portions 52 of the retaining member 5 for allowing the shank head 222 to enter the center retaining hole 50 . Thereafter, press the knob 21 to compress the elastic cushion ring 31 against the connection member 1 to force the shank head 222 to enter the center retaining hole 50 . After the bottom stop flange 2223 passed downwardly over the bottom side of the second plate member 7 , rotate the rotary locking device 2 through 90° angle to force the arched faces 2222 into the positioning grooves 531 respectively. After the user released the hand from the knob 21 , the elastic cushion ring 31 immediately returns to its former shape, causing the bottom stop flange 2223 of the locking shank 22 to be forced into engagement with the locating grooves 532 , enhancing locking tightness and avoiding accidental disengagement of the shank head 222 of the locking shank 22 from the center retaining hole 50 of the retaining member 5 at the second plate member 7 .
[0029] When going to detach the second plate member 7 from the first plate member 6 , press the knob 21 to compress the elastic cushion ring 31 against the connection member 1 and to move the bottom stop flange 2223 of the locking shank 22 downwardly away from the locating grooves 532 , and then rotate the rotary locking device 2 through 90° angle to move the arched faces 2222 away from the respective positioning grooves 531 and simultaneously to move the shank head 222 of the locking shank 22 into axial alignment with the longitudinal cut planes 2221 and the bottom stop flange 2223 into axial alignment with into axial alignment with the high inside wall portions 52 , enabling the shank head 222 to be retracted into the center retaining hole 50 . When released the pressure from the rotary locking device 2 at this time, the spring member 3 returns to its former shape, and therefore the second plate member 7 is unlocked from the first plate member 6 and can be moved away freely.
[0030] FIG. 8 illustrates an alternate form of the present invention. This second embodiment is substantially similar to the aforesaid first embodiment with the exception that the retaining member 5 is eliminated, and the mounting through hole 71 of the second plate member 7 is designed subject to the structure of the retaining member 5 , i.e., the second plate member 7 comprises two high inside wall portions 72 and two low inside wall portions 73 alternatively arranged around the mounting through hole 71 and connected to one another in a flush manner corresponding to the longitudinal cut planes 2221 and two arched faces 2222 of the locking shank 22 of the rotary locking device 2 , two positioning grooves 731 respectively located on the low inside wall portions 73 and two locating grooves 732 located on the bottom side of the second plate member 7 corresponding to the positioning grooves 531 .
[0031] In general, the invention provides a floating fastener for detachably fastening the second plate member 7 to the first plate member 6 . Subject to the spring force of the spring member 3 , the shank head 222 of the locking shank 22 is forced into the center retaining hole 50 of the retaining member 5 at the second plate member 7 when the longitudinal cut planes 2221 and the bottom stop flange 2223 of the locking shank 22 are respectively kept in alignment with the high inside wall portions 52 and the low inside wall portions 53 of the retaining member 5 . After insertion of the shank head 222 of the locking shank 22 into the center retaining hole 50 of the retaining member 5 at the second plate member 7 , press the knob 21 downwards and rotate the rotary locking device 2 to force the arched faces 2222 and the bottom stop flange 2223 of the locking shank 22 into engagement with the positioning grooves 531 and the locating grooves 532 respectively, and therefore the second plate member 7 is locked to the first plate member 6 firmly. Further, the shank head 222 can be made having one single longitudinal cut plane 2221 or two longitudinal cut planes 2221 , and the retaining member 5 can be made having one single low inside wall portion 53 or two inside wall portions 53 , achieving the same effects.
[0032] Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.
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A floating fastener includes a connection member fastened to a first plate member with a lock screw member, a retaining member installed in a second plate member, a rotary locking device coupled to the connection member and having a locking shank and a shank head with longitudinal cut planes and insertable through the retaining member, a spring member supported between the top wall of the connection member and a step around the periphery of the locking shank, a knob affixed to the top end of the locking shank and operable to bias the locking shank between a locking position where the shank head is forced into engagement with the retaining member and an unlocking position where the shank head is disengaged from the retaining member, and an elastic cushion ring supported between the connection member and the knob.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to medical imaging and, more particularly, to a system and method of imaging a region of interest (ROI) based upon patient size and/or task selection, preferably in computed tomography systems.
[0002] Typically, in computed tomography (CT) imaging systems, an X-ray source emits a fan-shaped beam toward an object, such as a patient. The beam, after being attenuated by the patient, impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array is typically dependent upon the attenuation of the X-ray beam by the patient. Each detector element of the detector array produces a separate electrical signal indicative of the attenuated beam received by each detector element. The electrical signals are transmitted to a data processing unit for analysis which ultimately results in the formation of an image.
[0003] Generally, the X-ray source and the detector array are rotated with a gantry within an imaging plane and around the patient. X-ray sources typically include X-ray tubes, which conduct a tube current and emit the X-ray beam at a focal point. X-ray detectors typically include a collimator for collimating X-ray beams received at the detector, a scintillator for converting X-rays to light energy adjacent the collimator, and photodiodes for receiving the light energy from the adjacent scintillator.
[0004] In one known CT imaging system used to image an ROI, imaging of a patient is conducted by moving the patient through a gantry. Preferably, it is desirable to minimize the patient's exposure to X-rays. To do so, improved signal processing has allowed the use of lower dose CT scans, such as the commercially available 0.5 second CT scanner. However, for larger and heavier patients, low signal streaking problems are known to occur due to low tube current values for certain angular views. One proposed solution to the low signal streaking problem is to determine a threshold based upon clinical evaluation of large or heavy patient scans. The determined threshold is then fixed, and corrections during image processing are performed based upon a signal strength that corresponds to X-rays being attenuated by large or dense objects. Problems arise, however, when reducing the dose in CT scans further, and in particular, for smaller patients and task dependent scans.
[0005] There is a need for a system that can apply the lowest possible patient doses based on patient size, especially for pediatric patients, and/or based on a task to be performed. Setting fixed patient thresholds to correct for low signal streaking problems in medium and smaller size patients does not improve reconstructed images of the patients, but may expose such patients to unnecessary X-ray radiation. Furthermore, certain sub-regions of the ROI may require a lower image resolution, or alternatively, a particular task such as Cardiac Artery Calcification Scoring may require a lower image resolution as compared to Cardiac Artery imaging thereby permitting application of a lower patient dose of radiation.
[0006] Since lower radiation exposure is an on-going goal in X-ray and CT development, it would be desirable to have an imaging system capable of processing imaging data according to an automated selection of a patient size and/or task dependency to reduce a patient's X-ray exposure during scanning of the patient.
BRIEF DESCRIPTION OF THE INVENTION
[0007] The present invention provides a system capable of processing imaging data according to selection of a patient size and/or task dependency to reduce a patient's X-ray exposure during scanning of the patient, and a method of processing imaging data that solves the aforementioned drawbacks.
[0008] A system and method of computer tomography imaging to reduce a patient's X-ray exposure based upon patient size and/or task selection prior to scanning of the patient are provided. The system includes a high frequency electromagnetic energy projection source to project X-rays towards an object, such as a patient. A detector receives the high frequency energy attenuated by the patient, and a plurality of electrical interconnects is configured to transmit detector outputs to a data processing system. The system also includes a computer capable of receiving a task and patient size dependency selection input and determining a threshold level based on the received inputs to separate the detector outputs into a number of projection sets for further image processing to reconstruct an image.
[0009] In accordance with one aspect of the present invention, a method of processing imaging data for a radiation emitting medical device includes the steps of providing a task and patient size dependency selection and setting a first threshold level based on the task and patient size dependency selection. The method also includes the steps of acquiring imaging data and separating the imaging data into a plurality of projection sets based on the first threshold level. The method further includes the step of uniquely processing the imaging data of each projection set to reconstruct an image.
[0010] In accordance with another aspect of the invention, a computed tomography system is provided. This system includes a high frequency electromagnetic energy projection source to project high frequency energy towards an object and a detector to receive high frequency electromagnetic energy attenuated by the object. The detector produces outputs that are transmitted to a data processing system by a plurality of electrical interconnects. The system further includes a computer programmed to receive the detector outputs and a task and patient size selection input, and determine threshold levels based on the received task and patient size selection input. The computer is further programmed to separate the detector outputs into a plurality of projection sets based on the threshold levels, and reconstruct the separated plurality of projection sets to produce a visual image.
[0011] In accordance with yet another aspect of the invention, a computer-readable medium having stored thereon a computer program having a set of instructions that, when executed by a computer, will cause the computer to receive a selection signal of a task and patient size input, and determine at least one threshold based upon the received selection signal. The computer program also has instructions to receive imaging data signals acquired with low-dose radiation, and synthesize the imaging data signals into a plurality of projection sets. The computer further includes instructions to process each projection set based on the selection signal and the threshold, and to reconstruct a visual image with improved artifact reduction.
[0012] Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The drawings illustrate one preferred embodiment presently contemplated for carrying out the invention.
[0014] In the drawings:
[0015] [0015]FIG. 1 is a perspective view of a CT imaging system incorporating the present invention.
[0016] [0016]FIG. 2 is a perspective block schematic diagram of the system illustrated in FIG. 1.
[0017] [0017]FIG. 3 is a flow chart showing a process of the present invention and implemented in the system of FIGS. 1 and 2.
DETAILED DESCRIPTION
[0018] A system and method is described for a computed tomography (CT) system capable of imaging an ROI. It will be appreciated by those of ordinary skill in the art that the present invention is equally applicable for use with different CT system configurations. Moreover, the present invention will be described with respect to the detection and conversion of X-rays. However, one of ordinary skill in the art will further appreciate, that the present invention is equally applicable in other imaging modalities.
[0019] Referring to FIGS. 1 and 2, an exemplary computed tomography (CT) imaging system 10 is shown as including a gantry 12 representative of a “third generation” CT scanner. Gantry 12 has an X-ray source 14 that projects a beam of X-rays 16 toward a detector array 18 on the opposite side of the gantry 12 . Detector array 18 is formed by a plurality of detectors 20 which together sense the projected X-rays that pass through a medical patient 22 . Each detector 20 produces an electrical signal that represents the intensity of an impinging X-ray beam and hence the attenuated beam as it passes through the patient 22 . During a scan to acquire X-ray projection data, gantry 12 and the components mounted thereon rotate about a center of rotation 24 . Detector array 1 8 and detectors 20 can be any number of high frequency electromagnetic energy detectors, such as gas-filled, scintillation cell-photodiode, and semiconductor detectors as is know to those skilled in the art of detector design.
[0020] Rotation of gantry 12 and the operation of X-ray source 14 are governed by a control mechanism 26 of CT system 10 . Control mechanism 26 includes an X-ray controller 28 that provides power and timing signals to an X-ray source 1 4 and a gantry motor controller 30 that controls the rotational speed and position of gantry 12 . A data acquisition system (DAS) 32 in control mechanism 26 samples analog data from detectors 20 and converts the data to digital signals for subsequent processing. An image reconstructor 34 receives sampled and digitized X-ray data from DAS 32 and performs high-speed reconstruction. The reconstructed image is applied as an input to a computer 36 which stores the image in a mass storage device 38 .
[0021] Computer 36 also receives commands and scanning parameters, such as patient size and task dependency, from an operator via console 40 that has a keyboard for entering commands and scanning parameters. An associated cathode ray tube display 42 allows the operator to observe the reconstructed image and other data from computer 36 . The operator supplied commands and parameters are used by computer 36 to provide control signals and information to DAS 32 , X-ray controller 28 and gantry motor controller 30 . In addition, computer 36 operates a table speed controller 44 which controls a variable speed table 46 during imaging of a patient 22 within gantry 12 . Particularly, table 46 is configured to move a patient 22 through a gantry opening 48 along an axis 50 , and may include a single or multiple speed settings.
[0022] In operation, a patient 22 or object is positioned within the CT scanner or imaging device 10 on the variable speed table 46 with a selected region of the patient chosen for scanning adjacent to the gantry 12 . A technician or health-care operator enters input into the operator console 40 , thereby defining a ROI or scanning region such as a thorax of the patient 22 , which includes a cardiac region 52 and a pair of non-cardiac regions 54 . The computer 36 then instructs the table speed controller 44 to move the table 46 towards the gantry opening 48 causing the patient 22 to enter the gantry opening 48 . Control mechanism 26 causes X-ray controller 28 to provide power and timing signals to X-ray source 14 while the gantry motor controller 30 causes rotation of gantry 12 to conduct an imaging scan of the patient 22 passing through the gantry 12 .
[0023] After scanning the ROI, detectors 20 send the X-ray data acquired to DAS 32 and image reconstructor 34 for digitalization and image reconstruction. Computer 36 then processes the digitized X-ray data to provide a reconstructed image of the ROI on display 42 .
[0024] Referring to FIG. 3, a flowchart illustrating the steps of a method and acts associated with a computer program in accordance with the present invention implemented in the system shown in FIGS. 1 and 2 are shown. The method and/or computer program is initiated at 100 by a technician or CT scanner operator who provides input into the computer at 102 to select a task and/or patient size dependency for a particular ROI. Generally, such operator-entered input can further include a starting position and an ending position along a common axis, such as axis 50 of FIG. 1 for conducting a scan. A patient size dependency query is then determined at 104 , and if patient size dependency is selected 106 , a scout scan is acquired 108 . After acquiring the scout scan 108 , the method and/or computer program proceeds to automatically determine a threshold at 110 , and receive a task (if any) and set the thresholds accordingly 112 . If patient size dependency is not selected 114 , the method and/or computer program receives also receives a task (if any) at 112 and sets the thresholds accordingly. After thresholds are set 112 , the method and/or computer program allows interactive threshold adjustment at 116 to change the threshold.
[0025] After allowing interactive threshold adjustment 112 , initial projections are acquired 118 using projection techniques known to those skilled in the art. For example, in one embodiment using parallel projection CT scanners, a patient in a two dimensional plane (x, y) is irradiated by an X-ray source. Alternatively, other sources such as ultrasound and MRI may be used. The radiation emitted by the source penetrates the patient along straight lines in the two-dimensional plane and is attenuated as it passes through the patient. A detector measures such attenuated signals and calculates the projection measurement data as line integrals using the following equation:
P n ( j )=∫∫ f ( x,y )∂( x cos n i +y sin n i −r j ) dxdy , (Eqn. 1)
[0026] wherein P n (j) are the calculated projections.
[0027] The acquired projections 118 that are lower than a defined threshold, T low are truncated to modify the projections 120 . Preferably, the truncated projections are modified based on their initial values. The modified projections 120 are then smoothed 122 . In one embodiment, the modified projections are grouped into first, second, and third projection sets having projection data above a first threshold, between the first and a second threshold, or below a third threshold respectively. Preferably, the first set of projections are smoothed using a lower order, 3-point smoothing technique, the second set of projections are smoothed using a medium order, 5-point smoothing technique, and the third set of projections are smoothed using a higher order, 7-point smoothing technique.
[0028] After smoothing the projections 122 , error projections, E n (j) are formed 124 and modified based on each error projection's strength 126 . In a preferred embodiment, the error projections are modified according to the following equations:
E n ( j )=P n ( j )− P n ( j ) smoothed (Eqn. 2)
E n ( j ) modified =E n ( j )* M _factor n ( j ), and (Eqn. 3)
M _factor n ( j )=exp(−1.0* P n ( j )/ C _factor), (Eqn. 4)
[0029] wherein C_factor is a constant that depends on the threshold selections, P n (j) are the initial projections, P n (j) smoothed are the smoothed projections, and M_factor n (j) is the modification factor that modifies the error projections, E n (j) to form the modified error projections, E n (j) modified . After modification 126 , the error projections are formed into a final set of projections 128 .
[0030] The method next decides at 130 whether the initial projections are greater than a first threshold, and if so 132 , performs Fourier deconvolution on the final set of projections 134 . If the initial projections are not greater than the first threshold 136 , an image is reconstructed 138 . Similarly, the Fourier deconvoluted projections 134 are used to reconstruct an image at 138 . The method then ends at 140 .
[0031] As previously discussed and in accordance with one aspect of the present invention, a method of processing imaging data for a radiation emitting medical imaging device, such as a CT scanner, includes the steps of providing a task and patient size dependency selection and setting a first threshold level based on the task and patient size dependency selection. The method also includes the step of acquiring imaging data for image reconstruction, and separating the imaging data into a plurality of projections sets based on the first threshold level. The method further includes the step of uniquely processing the imaging data of each projection set prior to reconstruction of the image.
[0032] In accordance with another aspect of the invention, a computed tomography system is provided. This system includes a high frequency electromagnetic energy projection source to supply a patient dose or project high frequency energy towards a patient or object, and a detector to receive high frequency electromagnetic energy attenuated by the patient or object. The detector generates outputs that are transmitted to a data processing system by a plurality of electrical interconnects. The system also includes a computer programmed to receive the detector outputs, and a task and patient size selection input. The computer determines threshold levels based on the received task and patient size selection input, and is further programmed to separate the detector outputs into a plurality of projection sets based on the threshold levels. The computer is also programmed to reconstruct the separated plurality of projection sets, preferably after further image processing, and produce a visual image.
[0033] In accordance with yet another aspect of the invention, a computer-readable medium having stored thereon a computer program having a set of instructions that, when executed by a computer, will cause the computer to receive a selection signal of a task and patient size input and determine at least one threshold based upon the received selection signal. The computer program also includes instructions to receive imaging data signals acquired with low-dose radiation and synthesize the imaging data signals into a plurality of projection sets. The computer program further includes instructions to process each projection set based on the selection signal and the threshold to reconstruct a visual image.
[0034] The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the append the steps ofing claims.
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A system and method of medical imaging is designed to reduce a patient's X-ray exposure during scanning based upon patient size and task dependency. The system includes receiving a task and patient size dependency input and determining threshold levels based on the received inputs to separate imaging data into a number of projection sets for further image processing and reconstruction of an image. Each projection set can then be independently processed based on the type of task and/or the patient size to allow reduced and modified X-ray doses dependent on the task and/or specific patient to be scanned.
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This application is a continuation of application Ser. No. 07/516,498 filed on May 4, 1990, abandoned.
FIELD OF THE INVENTION
The field of the present invention relates generally to protection devices for integrated circuits, and more particularly to low trigger voltage protection devices.
BACKGROUND OF THE INVENTION
Many attempts have been made in the prior art to protect semiconductor devices, including bipolar transistors, field effect devices, and integrated circuits against damage due to voltage and current transients. Such protection devices have commonly taken the form of diode or transistor circuits that have been incorporated on the integrated circuit chip for internal transient protection. The design engineer is nevertheless faced with the problem of having to use valuable chip space for forming protection devices. Particularly on devices containing a large number of pins, it has been found that the protection devices occupy a significant amount of space and, therefore, the chip can become undesirably large.
Protection circuits advantageously utilizing silicon controlled rectifier (SCR) arrangements are known, for example, from Avery, U.S. Pat. No. 4,484,561; Kokado et al., U.S. Pat. No. 4,631,657; and Avery, U.S. Pat. No. 4,633,283.
In typical SCR arrangements utilized in the protection of integrated circuits, the trigger or firing voltage under quasistatic conditions is on the order of 25 volts to 40 volts. However, in practice, pulse conditions typically prevail and the actual trigger voltage is generally higher because of the time taken to establish the plasma. When such an SCR arrangement is utilized as part of an ESD protection circuit on a VLSI chip, for example, damage to other parts of the chip could occur before the "snap-back" SCR conduction regime has been established, i.e. before the SCR has achieved its "shorted" state. It is therefore desirable to achieve a lower trigger voltage for the SCR.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the invention, a protection device comprises first and second terminals, a substrate of a first conductivity type, a first region of second conductivity type in the substrate, a second region of the second conductivity type in the first region, a third region of the first conductivity type in the first region and abutting the second region, a fourth region in the first region and extending beyond the boundary, a fifth region of the second conductivity type and spaced apart from said first region, and a sixth region of the first conductivity type and spaced apart from said first region.
In accordance with yet another embodiment of the invention, a first terminal of the protection device is in electrical contact with the second and third regions, and a second terminal is in electrical contact with the fifth and sixth regions.
In accordance with a further embodiment of the invention, the third and fourth regions are spaced apart to form source and drain regions of a field effect device and wherein a control gate means overlies the region between said third and fourth regions for controlling the degree of conduction between said third and fourth regions.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawing like items are identified by the same reference numeral and:
FIG. 1 shows a cross-section, not to scale, of an embodiment of the invention;
FIG. 2 shows a schematic of an equivalent circuit corresponding to the embodiment of FIG. 1;
FIGS. 3 and 4 show cross-sections, not to scale, of other embodiments of the invention.
FIG. 5 is a schematic circuit diagram showing the protection circuit of the present invention with an integrated circuit being protected.
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, an embodiment of the present invention is shown which is compatible with typical integrated circuit processing techniques. In FIG. 1, a substrate 10 is composed of a P - type conductivity semiconductor material such as silicon having a surface 11. It is typically relatively lightly doped, 10 13 /cc, and has a relatively low degree of conductivity. A region 12 of N - type conductivity, also relatively lightly doped and having relatively low conductivity is formed in substrate 10 at the surface 11. This region is usually referred to as a "well", in this case, an N - well.
N - well 12 has formed within it near the surface 11 a relatively heavily doped (typically 10 18 /cc) N + type conductivity region 14 and a relatively heavily doped P + type conductivity region 16, both having relatively high conductivity. Regions 14 and 16 are formed entirely within the boundary of N - well 12 and preferably abut one another.
A further region 18, is formed in N - well 12 in part, and in substrate 10 in part, thus extending through the boundary of N - well 12 into substrate 10. In the further region 18 may be either N + or P + conductivity type.
Substrate 10 has also formed within it at the surface 11 a relatively heavily doped N + type conductivity region 20 and a relatively heavily doped P + type conductivity region 22. Region 22 preferably abuts region 20. Regions 20 and 22 have relatively high conductivity and are formed entirely outside the boundary of N - well 12.
The surface 11 of substrate 10 and of the regions formed within it are covered by an insulating layer 24 which may be silicon dioxide, typically about 0.5 micrometers thick. Openings are provided through layer 24 for contacts. A first conductive layer 26, which may be aluminum, molybdenum, silicide or polysilicon, makes contact with each of regions 14 and 16. A second conductive layer 28 makes contact with each of regions 20 and 22. By way of example, conductive layer 26 is here connected to a terminal 30 and conductive layer 28 is connected to terminal 32. For example, FIG. 5 shows one possible arrangement, in which an integrated circuit 41 is connected between a first terminal 43 and a second terminal 45. In the present example, terminal 43 is a supply terminal for a voltage, VDD, of first polarity and terminal 45 is shown as a supply terminal for a reference voltage VSS, typically ground potential. However, terminal 43 can be a signal terminal rather than a supply terminal. In FIG. 5, a protection circuit 47 is connected between terminals 43 and 45, that is, in parallel with integrated circuit 41. Protection circuit 47 thereby protects integrated circuit 41 by turning on in response to transient voltages to conduct transient energy to a source of reference potential, ground in this example.
In operation, the arrangement of FIG. 1 functions as a protective device with "SCR-type" behavior to provide protection when a certain trigger voltage is reached or exceeded. When this has occurred, a low resistance path is provided between terminals 30 and 32 for limiting any voltage excursion. It will be helpful to an understanding of the operation of the protective device of FIG. 1 to consider the equivalent circuit of FIG. 2. The explanation will be simplified by first describing the operation without the presence of region 18.
Referring to FIGS. 1 and 2, N - well 12 (shown in FIG. 1) forms the base electrode of PNP transistor Q1 and P + region 16 forms its emitter, connected to terminal 30. P - substrate 10 forms the collector of transistor Q1. Resistor R1, connected between the emitter and base electrodes of transistor Q1, is formed substantially by the part of N - well 12 between region 14 and the edge of N - well 12 closest to N + region 20.
The emitter of NPN transistor Q2 is formed by N + region 20. Its base is formed by P - substrate 10 and its collector is formed by N - well 12. The emitter-base shunt resistor R2 is formed substantially by the region between the edge of N - well 12 and P + region 22. The arrangement of Q1 and Q2 forms an SCR having a threshold level above which it will be triggered into conduction, whereupon a "snap-back" voltage-current characteristic will be exhibited. The effective values of resistances R1 and R2 will primarily affect the value of the "holding current" below which the SCR will "unlatch" and substantially cease conduction.
The trigger voltage at which the conduction regime will be initiated is determined by breakdown voltages between component regions of the SCR. In the absence of region 18, triggering of the SCR will occur when the breakdown voltage between N - well 12 and P - substrate 10 is exceeded. In FIG. 3, this breakdown occurs across the junction between the base and collector electrodes of PNP transistor Q1 of NPN transistor Q2. In a typical CMOS process the breakdown voltage will be between about 25 volts and 40 volts but, as earlier stated, the time taken to establish a plasma providing full conduction will result in higher effective "snap-back" trigger voltages for the short pulse durations encountered in typical electrostatic discharge transients.
In FIGS. 1 and 2, because of the higher doping level of region 18, the breakdown voltage between P + region 18 and N - well 12 will be less than the breakdown voltage between P - substrate 10 and N - well 12. In effect, the P + region 18 rather than substrate 10 forms the collector electrode of PNP transistor Q1. Accordingly, the lower breakdown voltage will control, and thus a lower "snap-back" trigger voltage for the SCR is achieved. The actual value of the trigger voltage can be controlled to a certain extent by selecting different spacings between P + region 16 and P + region 18.
In FIG. 4, the further region 18' is of relatively highly doped N type conductivity material (N + ). The breakdown voltage between N + region 18 and substrate 10 is lower than the breakdown voltage between N - well 12 and substrate 10. Consequently, the trigger voltage for the SCR is lowered in this manner.
Referring now to FIG. 3, a gate electrode overlies the portion of N - well 12 between regions 16 and 18. When the gate electrode is appropriately biased, a conduction channel is established between regions 16 and 18. This is equivalent to conduction in the emitter collector path of PNP transistor Q1 and will lead to a lower trigger voltage for the SCR. By maintaining the gate at a reference potential, appropriate biasing can result from a positive transient potential on conductive layer 26.
The devices of the invention can be fabricated utilizing standard photolithographic and etching steps for definition and ion implantation for forming the doped regions. Typically, a silicon substrate is used with, for example, boron as a P type dopant and phosphorus as an N type dopant, other suitable materials may be used.
Modifications of the various embodiments of the invention may occur to one skilled in the art. For example, while the exemplary embodiment has been described in terms of particular conductivity types, converse conductivity types may be used so long as the relative conductivity types remain the same. Such and like modifications are intended to be within the spirit and scope of the invention, and the appended claims.
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A device for protecting an integrated circuit from transient energy is disclosed. This device provides an SCR having a reduced "snap-back" trigger voltage.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method for advertising for sale classroom materials and services to students who are taking or about to take a specific course/class at a school. In particular, the present invention relates to a method for advertising over a web site on the Internet classroom materials such as required textbooks, laboratory tools, class notes and tutoring services offered for sale by students at the school.
[0002] College or university students are typically required to buy certain textbooks for the courses that they are enrolled in. These textbooks can be bought either in new or used condition at the bookstores. In some cases, other students who have previously taken the class may sell their textbooks to the students about to take the class. Such used textbooks are typically advertised on bulletin boards or newspapers, both of which are not convenient since a student looking for these books must spend considerable time sorting through bulletin boards and newspapers for the right information.
[0003] A student may also sell their used books over the internet using a website. One such site, ScrewTheBookstore.com, allows the student to offer their used textbooks to other students. However, at this time, the site only allows students looking for used textbooks to search the entire database for these books using the book's title, author, or ISBN number.
[0004] There is a need to conveniently associate used textbooks to specific courses/classes taught by specific professors at a school in order for students looking for these textbooks to find them quickly.
[0005] In addition, students who have previously taken the specific course/class may wish to sell any laboratory tools that they have purchased for the course/class. Further, a good student may want to sell their class notes and to offer tutoring services to student who are taking or about to take the specific course/class.
SUMMARY OF THE INVENTION
[0006] The invention is a method for advertising classroom materials and services associated with a specific course/class at a school over a communication network. A site on the network can be accessed nationally, but will have a page dedicated to a particular school. The school can be a college, university, high school, private school, community school, government agency, museum, or any other entity that offers classes in any course. Classroom materials and services include textbooks (whether required or suggested), laboratory tools, class notes (including notes, outlines, homework exercises, quizzes, tests and handouts), tutoring services, and other academic materials and services related to the specific course/class. Using the invention, students would be able to sell their used textbooks, lab tools, class notes, and tutoring services to fellow students at the same school, allowing for quicker transactions. The site will include a page containing the specified school's required textbooks for its courses/classes. This will allow both sellers and buyers to determine whether the books will be used for the current and/or following quarter or semester.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows the system for accessing the site.
[0008] FIG. 2 shows the flow diagram for accessing the site.
[0009] FIG. 3 shows the flow diagram for selling on the site.
[0010] FIG. 4 shows the flow diagram for buying on the site.
[0011] FIG. 5 shows an example page on the site.
DETAILED DESCRIPTION
[0012] FIG. 1 shows a network for practicing the invention. A user terminal accesses the site over a communication network. The user terminal can be a personal computer (PC) such as a desktop computer or laptop computer, a pda, a cell phone or any other device that transmits and receives data. The communication network can be a Local Area Network (LAN), Wide Area Network (WAN), wireless network, wired network, Public Switched Telephone Network (PSTN), intranet, extranet, or Internet. The user terminal can connect to the communication network using Ethernet, dial-up, DSL, cable, satellite, wireless, wired or any other connecting system. The site can be located anywhere on the network. In one embodiment, the user terminal is a PC that accesses a web site hosted by a server over the Internet. The web site can be created by any web site tool such as Microsoft FrontPage.
[0013] FIG. 2 shows the method for practicing the invention. A user accesses the site. The site displays a listing of schools. The user then selects a school. For the selected school, the site displays the courses/classes for the current and/or next quarter or semester. The user then selects a particular course/class. For the selected course/class, the site displays available classroom materials and services. The user then selects either sell or buy for a desired classroom material or service. FIG. 5 shows an example of a page of the site. Listed under the specific course/class are a plurality of classroom materials and services. Under “Required Textbooks,” the bracketed “5” indicates that there are five users advertising for sale the textbook. Under “Lab Tools,” the bracketed “3” indicates that there are three users advertising for sale their laboratory tools. Under “Class Notes,” the bracketed “10” indicates that there are ten users advertising for sale their class notes. Under “Tutoring,” the bracketed “0” indicates that there are no user advertising tutoring services. Using brackets to indicate the number of users offering for sale the particular items makes it convenient for a current user to determine whether there are new sellers from the last time the site was accessed. Alternatively, the site can just indicate whether there are any of these items available or not without indicating the number of sellers. The page shown in FIG. 5 is just an example and may contain more or less information as long as the classroom materials and/or services to be sold or bought are associated with a specific course or class.
[0014] FIG. 3 shows the flow diagram if the user selects sell for the desired classroom material or service. The site displays a request for the seller to register. A previously registered seller can just enter a screen name and password to register, and, if desired, can hit a modify button to modify the seller's previously entered registration information. A new seller would have to create an unique screen name and a password, and enter their contact information. The contact information can include any of name, mailing address, email address, telephone number or any information that can be used to contact the seller. After the user registers, the site displays a request for information for selling the desired classroom material or service. If the user selected a textbook to sell, the requested information can include but is not limited to condition of book, price and any additional comments that the user would want a potential buyer to read. If the user selected lab tools to sell, the requested information can include but is not limited to condition of tools, price and any additional comments that the user would want a potential buyer to read. If the user selected class notes to sell, the requested information can include but is not limited to quarter/semester of class taken, price and any additional comments that the user would want a potential buyer to read. If the user selected tutoring to sell, the requested information can include but is not limited to price, grades of the user and any additional comments that the user would want a potential buyer to read. After the user provides the requested information, the site updates the status of the availability of the selected classroom material or service. The user may then sell or buy other items for the specific course/class or select a different course/class for the particular school. Also, the user may select a different school or just leave the site.
[0015] FIG. 4 shows the flow diagram if the user selects buy for a desired classroom material or service. For the selected classroom material or service, the site displays a list of screen names of sellers and can also display the information provided by the sellers for the particular classroom material or service. The user can then select one of the screen names representing a seller. The site then displays the seller's contact information.
[0016] According to another embodiment of the present invention, the user may be required to pay a fee to sell a classroom material or service. A set fee can be charged at the time the user registers at the site. Alternatively, the fee can be a percentage of the price that the classroom material or service is advertised or sold.
[0017] According to another embodiment of the present invention, the user may be required to register in order to buy a classroom material or service. A set fee can be charged at the time the user registers at the site.
[0018] According to another embodiment of the present invention, the user can select the school or course/class by entering a specific school or course/class into a search field. Further, the user can search the database of the site for courses/classes that use a specific textbook by entering the textbook's title or author or ISBN number. The user can then select to sell or buy the textbook listed under one or more courses/classes from one or more schools.
[0019] According to another embodiment of the present invention, the user can select buy or a request to buy a specific classroom material or service that does not have a seller. In this situation, the page would display to a subsequent user that a buyer wishes to buy the particular classroom material or service. The display can indicate that the particular item is requested or alternatively, indicate the number of buyers requesting the particular item. The subsequent user can then select to sell the particular classroom material or service to the requesting buyer or buyers.
[0020] According to another embodiment of the present invention, the user can save their selected courses/classes. The saved selected courses/classes can then be presented to the user during the current visit and also during subsequent visits to the site. Presenting the saved courses/classes allows the user to quickly go to a particular course/class without having to go to a listing of schools and/or listing of courses/classes. A listing includes presenting the listed items using menus such as drop down menus.
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A method for advertising for sale classroom materials and services such as textbooks, laboratory tools, class notes and tutoring over a communication network. The classroom materials and services are linked to specific courses or classes offered by a particular school. Students would then be able to sell their used textbooks, lab tools, class notes and tutoring service to fellow students at the same school allowing for quicker transactions.
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BACKGROUND OF THE DISCLOSURE
The field of the invention is waste drains and the invention relates more particularly to waste drains which are also capable of functioning as waste receptors. Modern plumbing codes typically require indirect waste receptors in restaurants, food processing plants and other areas where food is handled or processed. Such waste receptors are also useful as floor sinks since the receptor has a body which is capable of retaining a portion of solid waste away from the floor and yet collecting them prior to their entry into the waste system. Such waste receptors are capable of holding strainers and buckets which assist in this function.
Most plumbing codes required the waste receptor to have a smooth, easy to clean, corrosion resistant interior surface and the typical cast floor drain does not meet this requirement because such drains have rough interiors with pockets and crevices which can harbor dirt and bacteria.
Another problem associated with waste drains is the leakage of waste around the exterior of the drain. Such leakage is quite common in concrete floors where cracks caused by shrinkage usually exists and flashing has been used in the past to assist in reducing this problem. The problem is particularly acute where the drain is on a second or higher floor since leakage will often find its way through the ceiling below.
A drainage receptor which appears to be cast is shown in U.S. Pat. No. 3,713,539 and, as pointed out above, such drains do not typically have the requisite smooth surfaces to prevent harboring of bacteria and the like. Furthermore the drain has no provision for collection of fluids which have seeped around the outside of the drain. Seepage prevention means are quite commonly provided in drains which do not have receptors and examples of various methods of controlling seepage are shown in U.S. Pat. Nos. 2,885,689 to Morris; 1,766,621 to Flemming; and 1,749,879 to Flemming. The seepage control methods shown in the above patents however are not readily adopted to waste receptors and a better device for providing seepage control in waste receptors is needed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved waste receptor.
It is another object of the present invention to provide a waste receptor with means for effectively controlling seepage.
The present invention is for a fabricated floor drain for waste reception. The drain has a receptor body having an outwardly extending top rim around the top thereof, side walls and a bottom outlet. Flange means are sealingly affixed about the entire exterior of the side walls of the receptor body at a point below and parallel to the top rim. The flange means has a generally flat and inwardly sloped shelf portion which extends outwardly away from the receptor body. At least one weep hole is located in a side wall of the receptor body just above the point at which the flange means is connected to the wall. Membrane clamp means are pressed against the under surface of the top rim and have at least one clamp bar which abuts the upper surface of the flat shelf portion of the flange means at one end and the under surface of the top rim at its other end. Preferably the receptor body is rectangular and there are four clamp bars, one along each side of the receptor body. The clamp bar may be urged against a water proof membrane which is held between the bar and the shelf portion of the flange and the bar may be locked in place by a plurality of nuts threaded onto studs which are affixed to the clamp bars. The receptor is designed to permit the inclusion of a grate as well as a sediment bucket and a dome shaped bottom strainer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the fabricated floor drain in the present invention.
FIG. 2 is a cross sectional side elevation of the drain in FIG. 1 installed in a floor.
FIG. 3 is an enlarged side view taken along line 3--3 of FIG. 1.
FIG. 4 is a bottom perspective view of a grate cover useful with the floor drain of FIG. 1.
FIG. 5 is a perspective view of a sediment bucket useful with the floor drain of FIG. 1.
FIG. 6 is a top perspective view of a dome bottom strainer useful with the floor drain of FIG. 1.
FIG. 7 is a sectional view taken along line 7--7 of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The floor drain of the present invention is shown in perspective view in FIG. 1 and indicated generally by reference character 10. Drain 10 has a waste receptor body 11 which is generally square in cross section. Body 11 should be fabricated in a manner so that the interior thereof is smooth and free of crevices, cracks and other areas for harboring bacteria. The body of the drain in the present invention may be deep drawn from a single piece and only the bottom outlet 12 and flange 13 need be continuously seam welded to the drawn body. The preferred material of construction is 14 gauge type 304 stainless steel although other types of stainless steel such as type 316 and other materials of construction may be used depending upon the desired strength, corrosion resistance and fabrication techniques available. The flange of the present invention need not extend further out than the top rim.
The drain, after installation on grade in a concrete floor is shown in cross sectional view in FIG. 2. The surface of the floor is indicated by reference character 14 which is in the same plane as the upper surface of rim 15 of the drain. The bottom outlet 12 is, of course, connected to a drain pipe (not shown). Because of the tendency of concrete to expand and contract at the intersection of the drain rim and the concrete, some means is necessary to intercept such leakage and convey it to the interior of the drain. As pointed out above, this need is particularly acute when the drain is installed above grade.
The drain body 11 rests in the ground 16 and a layer of sand and gravel 17 supports a water impervious membrane 18 of the type commonly used in building construction to prevent water seepage into the ground. The concrete or other flooring 19 is placed above membrane 18.
A persistent problem in preventing water seepage about the outside of a drain body has been the means used to connect the water impervious membrane to the drain in a manner which minimizes the amount of water which can escape without passing through the bottom outlet of the drain. Elaborate clamping means such as those shown in the above-described U.S. Pat. No. 1,749,878 have been utilized but such methods have not proved practical for the larger waste receptors of the type shown in the drawing. The method for clamping the water proof membrane to the flange is shown best in FIG. 3. There it can be seen that flange 13 has a generally flat and inwardly sloped shelf portion 20 and a downwardly extending projections 21 which is continuously seam welded to the receptor body 11. Projection 21 extends around the entire periphery of the receptor body and the weld line 49 is at the bottom of projection 21. Weep holes 22 are positioned so that the lowermost point of the holes are about at the point where projection 21 meets the outer wall of receptor body 11. Preferably a small amount of gravel or other porous material 23 is added around the intersection of the flange and the drain body before the concrete is poured above the flange. This allows seepage to more readily reach the weep holes.
The clamping means used to hold water proof membrane 18 against the generally flat shelf portion 20 of flange 13 has a clamping bar 24 which is welded to a threaded stainless steel stud 25. Coupling nut 26 is screwed over the upper end of stud 25 and is screwed sufficiently far down so that the bar, stud and nut may be placed over the membrane which, in turn, has been placed on the upper surface of the generally flat shelf portion 20 of flange 13. Then, coupling nut 26 is unscrewed with respect to the stud 25 until its upper surface hits the lower surface of rim 15 at which point it forces clamping bar 24 tightly against membrane 18. The nut 26 should extend below the rim so that it may be contacted by a wrench. The advantage of this particular clamping means is many fold. First, it does not puncture or cause any leaks in the membrane itself. Secondly, because of the use of a plurality of studs 25 any lack of straightness in shelf 20 may be corrected by a flexing of the clamping bar 24. The other three clamping assemblies are identical to the one just described and all common elements have been given the same reference characters.
For most above grade installations, two pours of concrete are made. The first pour is made to the level of the bottom of the flange. The water proof membrane is then laid over the top of the first pour and clamped to the flange as described above. The second pour is then made over the membrane to the rim of the drain.
A particularly effective cover assembly for use with the drain of the present invention is shown in FIG. 4 and indicated generally by reference character 30. This cover or grate has a plurality of openings 31 and the size and shapes of such openings are dictated by the particular end use. For instance, if it is necessary to provide a grate for grocery stores the grate should have openings which do not permit high heels to enter and a square one quarter inch opening has been considered satisfactory for this use. The grate has a reinforcing rim 32 which extends about the entire periphery thereof at a point inwardly from the edge and thus a double layer comprising the grate surface 33 and the reinforcing rim 32 exists around the entire outer edge of the apparatus. Turning back to FIG. 3 it can be seen that the upper surface of the grate can be made flush with the upper rim 15 of the drain to provide a particularly safe and attractive assembly. Reinforcing rim 32 rests on a support shelf 38 which is formed in the side wall of receptor body 11 and a plurality with dimples 39 touch the side wall 11. A channel member 34 serves as a cross brace and has a plurality of openings 35 shown in FIG. 7 which corresponds with the openings 31 in the grate. Reinforcing rim 32 also extends downwardly and has a minimum of two dimples 39 per side so as to assist in locking the grate in place, otherwise the grate might slide when stepped on and could create a hazard. Similarly channel members 36 and 37 provide bracing for the upper surface 33 of grate 30 and may likewise be provided with openings similar to openings 35.
The waste receptor of the present invention may be readily used in combination with a sediment bucket such as that shown in FIG. 5. A particularly effective sediment bucket may be fabricated from two sheets of stainless steel and provides a bucket with side 40, a bottom 41 and 42. Feet 42 are sufficiently long so that the bottom of the bucket is above the dome strainer 44. A handle 43 facilitates removal for emptying.
Further, to decrease the possibility of any blockage of the drain pipe a dome bottom strainer 44 may be placed over the bottom outlet 12 below the sediment bucket to provide an assembly which minimizes drain blockage problems. Strainer 44 is made from a center dome 45 which has a plurality of holes 46. A ring 47 is welded to dome 44 and has a plurality of drain holes 48.
It can thus be seen that particularly effective drain assembly can result from the use of the drain receptor of the present invention. Not only can the interior of the drain be provided with rounded corners, as shown in the drawings, but the interior surface, if fabricated from a stainless steel or other satisfactory material, may be readily polished to eliminate any cracks, crevices or porosity for entrapment of bacteria. Such a drain can be used in hospitals, chemical plants, food processing plants and other areas where sanitary conditions are important. Not only does the drain reduce bacterial collection but also seepage around the flange is minimized by the membrane clamping and weep holes described above.
The flanges positioned about the periphery of the drain body not only function to collect seepage but also provide support of the drain in the concrete floor. Such flange can help anchor the device by forcing it to move up and down with the concrete thus preventing the drain from sinking slightly below the concrete surface or raising slightly above it.
While the drain in the present invention is shown as having a rectangular body and more particularly a square body it may, of course, be circular and two or more clamp bars may be utilized which, or course, would be semi-circular or otherwise correspond to the shape of the body of the drain. While the clamp bars shown in the drawings have been shown as being affixed by a plurality of studs and coupling nuts, other affixing means may be used such as one or more springs or other clamping assemblies. It is highly desirable, however, that the clamping assembly not provide any further opening in the rim 15 of the drain body as this could cause another source of seepage which is eliminated by the assembly shown in the drawings. Furthermore, the clamping system should not require a hole in the membrane or in the flange itself as this could also provide a liquid path outside of the drain body and bottom outlet.
While the studs 25 are shown as welded to bars 24, it would, of course be possible to weld the coupling nuts 26 to the bars and provide some turning means such as a hexagonal portion on the studs so that they could be screwed upwardly against the under surface of the rim. Alternatively the studs could be welded to the rim and the coupling nuts screwed into the bottom of the studs against the bars.
The present embodiments of this invention are thus to be considered in all respects as illustrative and not restrictive, the scope of the invention being 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 therefore are intended to be embraced therein.
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A fabricated floor drain for waste reception. The drain has a receptor body having an outwardly extending top rim and a flange which extends outwardly about the entire exterior of the side walls of the body. The flange functions both to anchor the drain as well as to provide a seal for a water proof membrane. Seepage drain holes are positioned at the intersection of the flange and side walls.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/181,451 filed on Feb. 10, 2000.
FIELD OF THE INVENTION
[0002] This invention relates to networked electronic communication systems for exchanging information and transacting business via the Internet and more particularly, although in its broader aspects not exclusively, to methods and apparatus for providing a Web-based information exchange service for the shipping industry.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] The shipping industry comprises a large number of participants who conduct business primarily through an inefficient combination of postal mailings, telephone messages, facsimile transmissions and, to an increasing extent, email messages. For example, the marine transportation of petroleum involves the worldwide movement of crude oil and petroleum products on a host of tankers, operating primarily under international flag, which are owned by many different foreign and domestic ship owners. Domestic shipping is typically handled by coastal barges owned by competing barging companies. Most vessels are committed on a voyage-by-voyage basis, which is referred to as spot chartering. Many concentrate on a specific market, such as the Caribbean or Latin American markets. A smaller number of vessels are committed to a single charter for a fixed period of time, typically one year or longer.
[0004] A high percentage of both term and spot market shipping is conducted through brokers who are normally paid a commission for each fixture by the vessel owners. The brokers provide both shippers and charterers with market information. Some brokers post such information on the World Wide Web as a convenience to their clients. Each shipment further requires the performance of ancillary services which are provided by inspection companies, customs and customs agents, ship agents, linehandlers, chandlers, tugboat and pilot services, bunker providers, and the like, each of which must be separately identified, examined and contracted with.
[0005] There is accordingly a clear need for improved mechanisms for matching the needs of charterers desiring to transport goods with the services available from carriers and other shipping service providers.
[0006] In a principal aspect, the present invention takes the form of an Internet-based shipping marketplace which participants can use to exchange information and make commitments relating to the transportation of goods. In its preferred embodiment, the invention is implemented by one or more Web database servers which serve as an information and transaction hub for connecting charterers, ship owners and other carriers, brokers and agents, and shipping service providers.
[0007] As contemplated by the invention, ship owners, carriers and shipping service providers post information describing available services to the exchange server by using a form-based Web browser interface, or by uploading descriptive data in a structured format to the server. As used herein, the terms “ship owners” and “vessel owners” should be understood to include ship operators who do not necessarily own the ships they operate. Charterers may then post their requirements to the server in a structured format, also using a form-based Web browser interface. The server compares the requirements posted by the charterer with the descriptions of available services posted by the service providers, thereby matching the needs of the charterer with relevant services.
[0008] The exchange server is preferably adapted to utilize the posted information in a variety of ways, depending on the services requested. The charterer may simply be provided with the information concerning available services for review. The exchange server accordingly provides search facilities that allow charterers to conveniently search for, identify and compare services of interest prior to making a commitment. Vendors are likewise given access to market information that allows them to identify and better meet the current needs of charterers. In addition, as summarized below, charterers and vendors may use the services of the exchange to secure mutual commitments regarding defined services.
[0009] In a first mode, the charterer may use select desired services from matching availability data provided by the server and establish communications with the vendor via the exchange server to exchange further information before a commitment is made.
[0010] In a second mode, the charterer's initial request defining a needed service may be treated as a “request for quote” and the matching availability information which is posted by vendors and identified by the exchange server may be treated as a binding offer by each vendor which the requesting charterer may then accept, thereby creating a binding commitment.
[0011] In a third mode contemplated by the invention, charter services may also be aggregated to create a commodity sub-market for specific services of that kind. By way of example, a sub-market might be created for shipping petroleum between the Persian Gulf and United States Gulf ports. Carriers (ship owners), using a Web browser interface, may then post binding competitive offers to sell commodity services in that defined class, and charterers may post offers to buy services in that class, thereby creating an open-market environment for that class of services which is managed by the exchange server. The server matches the offers and bids to conclude commitments between the parties, and generates market information which is generally accessible to registered vendors and charterers indicating the current market price at which commitments have been most recently made for the service commodity which is the subject of that sub-market. In addition, such market information may be made publicly on a Web site published by the exchange server, or through other channels, while preserving the confidentiality of data on specific transactions.
[0012] The exchange server makes available industry-standard contract forms and documentation which define the terms upon which commitments are made, and provides generates full documentation for each commitment which is then provided to the parties to that commitment. The transmission of information and any documentation which describes each transaction, as well as any transfer of funds, is preferably conducted using conventional secure transmission means, such as the industry standard Public Key Infrastructure (PKI) and Secure Socket Layer (SSL) protocols.
[0013] As further contemplated by the invention, ancillary services offered by the same or different vendors may also be presented to the charterer, either at the same time the prime commitment between the charterer and the carrier is made, or separately. In accordance with the invention, a Web-based interface is provided which permits ancillary service providers to post descriptions of available services to the exchange server. By way of example, marine shipping services may be described by structured data posted to the exchange server by inspection companies, bunker providers, tugboat and pilot services, connecting barging and land based carriers, customs and customs brokers, linehandlers, etc. Frequently, these services are offered at the point of origin (loadport) or destination (disport) for a particular route. As in the case of services offered by carriers, commitments for such ancillary services may be made in an open-market, competitive environment.
[0014] The present invention significantly lowers costs for both charterers and shipping service providers by providing both with the information needed to secure advantageous business relationships, by automating tasks now performed by conventional means, by simplifying transactions, reducing misunderstandings and providing accurate records through the use of standardized electronically-communicated documentation, and by promoting competition among vendors.
[0015] These and other objects, features and advantages of the present invention may be better understood by considering the following detailed description of the preferred embodiment of the invention. In the course of this description, frequent reference will be made to the attached drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0016] [0016]FIG. 1 is a block schematic diagram of a Web-based shipping exchange that implements the invention.
[0017] [0017]FIG. 2 is a data flow diagram illustrating the manner in which negotiations occur between ship owners and charterers.
DETAILED DESCRIPTION
[0018] The shipping information exchange and transaction system contemplated by the invention preferably takes the form of a Web-based business-to-business communication, database and transaction system.
[0019] The methods and apparatus contemplated by the invention use conventional Internet World Wide Web instrumentalities. A Web database server 101 communicates with the Internet 100 via a secure interface and maintains a database 105 including:
[0020] 1. Participant Registration Information (indexed by ID)
[0021] 1. User names and passwords for secure access.
[0022] 2. Contact information including mailing addresses, phone and fax numbers, email addresses.
[0023] 3. Financial and banking relationships for funds transfers and to confirm credit status.
[0024] 4. Corporate history and descriptive information.
[0025] 2. Descriptions of offered services
[0026] 1. Shipping services
[0027] 1. Vendor ID
[0028] 2. Route description or geographic zone(s) serviced
[0029] 3. Dates available
[0030] 4. Capacity (minimum and maximum)
[0031] 5. Carrier type (bulk carrier, dry goods carrier, container ships, petroleum, etc.)
[0032] 6. Cost
[0033] 2. Ancillary services
[0034] 1. Vendor ID
[0035] 2. Location available
[0036] 3. Dates available
[0037] 4. Capacity (minimum or maximum, if any)
[0038] 5. Service type (e.g. inspection services, customs broker, linehandler, pilot, tug service, etc.)
[0039] 6.
[0040] 3. Description of services desired by charterers or other vendors
[0041] 1. Charterer or Vendor ID
[0042] 2. Route or location description (load and discharge location)
[0043] 3. Date(s) needed
[0044] 4. Capacity required
[0045] 5. Carrier or Service type desired
[0046] 6. Offered fee amount (or limit)
[0047] The foregoing information is preferably stored in a Web-enabled relational database system of conventional design, such as the Oracle 8i Web Database system offered by Oracle Corporation of Redwood Shores, Calif., or the equivalent. Such database systems typically operate in the environment provide by an operating system host such as Unix, Linux or Windows NT, on conventional computer hardware provided with a high speed Internet connection. Web database systems of this kind typically include support for an HTML forms-based interface with client browsers using the HTTP protocol. Data is exchanged between the database 105 and client computers via the Internet by performing SQL search, retrieval and update operations which, on the client side, are presented in HTML Web pages and forms which may be completed and submitted to the exchange server and which may include Java applets for performing selected functions on the client side.
[0048] Participants who use the services provided by the exchange server may use conventional form-based registration procedures to post participant data to the database. Thereafter, the exchange server employs user account information and password protection to control access to services and data provided by the server, limiting access to authorized personnel only. This access control prevents unauthorized persons from uploading or accessing data or obtaining services that are intended for use only by authorized registrants. Moreover, data is preferably partitioned so that only authorized participants may get access to their own account data, or to data describing transactions to which they are a party. Still further, access privileges vary for different data so that, for example, data describing completed commitments may be modified only by authorized system supervisors, but may be viewed by the authorized charterer or vendor who is a party to the transaction.
[0049] These services and data may be accessed by transmitting conventional HTML web pages using HTTP to client computers from the exchange server 101 via the Internet 100 . The connected client computers, to be described, execute conventional web browser programs, such as Netscape Navigator or Microsoft's Internet Explorer, to view Web pages, and to complete and submit HTML forms to the exchange server 101 . Data in the form of structured data files (advantageously expressed in the Extended Markup Language “XML”), as well as image, video, audio and text files may be uploaded to the exchange server by the a participant by requesting an upload services made available by web pages from the server, typically by entering the name of the data file to be uploaded, and then using conventional FTP file transfers to upload the identified data files to the server for storage and further processing. Participants may employ conventional text, image, video and audio composition and editing tools to create or update files, which may then be uploaded to the server.
[0050] The exchange server 101 sends information to and receives information from multiple participants that are illustrated in FIG. 1 by a charterer 107 , a ship owner 110 , an inspection company 115 , a linehandler 120 , a customs agent 125 , a barging company 130 , a tugboat operator 135 , a pilot 140 , a bunker provider 145 , and an agent 150 . After all of these participants has registered and posted information describing their organization, the vendors further complete HTML forms issued by the server 101 , or upload previously created data files, including XML data derived from a vendor database, to provide searchable structured data defining those shipping services which are offered. The pre-registered charterer 107 then logs into the exchange and submits a request for services by completing an HTML form which accepts structured data defining the desired shipping service. The exchange server then performs an SQL retrieval from the relational database 105 which matches the attributes of the available services with the attributes of the desired shipment. The availability data on the matching services returned by the database 105 are then converted into an HTML Web page form listing which is returned to the charterer 107 for inspection and further action.
[0051] At that time, depending upon the mode of operation being employed, the charterer 107 may do nothing, may communicate directly with a particular vendor, such as the ship owner 110 , to secure more information, may treat the listed information as a binding offer for services which may be accepted to create a commitment, or may be informed that a commodity sub-market has been created for the requested services and be advised of the current market price and terms available in that sub-market for immediate purchase.
[0052] When a commitment is made for services, the server supplies a copy of standardized documentation for each party's records and, if appropriate data is in place to do so, automatically transfers funds as specified by the commitment using previously supplied financial data (bank and account numbers, credit card information, authorizations, etc.) previously stored in the secure database 105 . The documentation, which may take the form of industry standard Portable Document Format (PDF's Adobe Acrobat®) files and/or XML data, may be transferred to those participants who are parties to the transaction and further saved in the database 105 for future reference by those parties. In accordance with an important feature of the invention, the exchange server preferably provides and retains a complete electronic “paper trail” which fully and automatically documents all transactions.
[0053] After, prior to, or concurrently with the transaction that creates a commitment between the charterer and a particular carrier (e.g., between charterer 105 and ship owner 110 ), the charterer and the vendor may also be advised of the availability of ancillary services which will be needed to consummate the shipment. For example, the exchange server may respond to a request from the charterer by returning one or more Web pages which list, in addition to the services of available carriers, the services of inspection companies and linehandlers at both the loadport and disport, and the services of customs brokers at the disport in case of international shipments. Similarly, the carrier may be advised of services it may require, including tugboat services, pilots, bunker providers and customs brokers. Note that, in the later case, the registered participant which acted as a vendor in one phase of arranging a shipment acts a purchaser of support services in another phase. In both cases, the exchange server 101 facilitates the negotiation which leads to desired commitments with these ancillary service providers, and provides full documentation and funds transfer services to the participants.
[0054] In some cases, a party to an existing past commitment may be unwilling or unable to fulfill that commitment and may wish to offer its contractual right to buy or to sell to another who will actually perform or use that service. To facilitate this, the exchange server 101 may advantageously maintain an auction facility under which holders of contract rights secured using the exchange may place those previously bargained-for rights on the market again for purchase by others. Thus, for example, a charterer may offer its right to ship petroleum from the Persian Gulf to a U.S. Gulf port to another charterer by submitting those rights to the auction facility. Similarly, a carrier may offer its contract right to payment for transporting a given shipment to another carrier using the auction. To facilitate this possibility, the transferability of commitments made using the server is preferably a standard, although optional, term of each commitment. In should be noted that, in the open-market environment created for services which fit into predefined commodity categories, contracts rights previously secured in that open market may be readily resold in the same market. As with any open market, the open market in such shipping commodities allows participants to execute hedging and investment strategies that tend to provide beneficial stability to the market and security to the participants.
[0055] Web Site Implementation
[0056] The structure and operation of an Internet Web site that implements significant features of the invention is described below. This Web site provides end-to-end logistics management solutions for the oil industry, uniting key partners in the value chain and facilitating transactions among buyers and sellers, cutting costs, and creating new business opportunities for the participants. The Web site makes the core ship chartering process available online while simultaneously integrating the service offerings of key constituencies that fulfill the requirements of a ship, both pre- and post-fixture. The Web site provides services to ship charterers and owners, as well as inspection companies, ship agents, barging companies and terminalling facilities. The services provided to participants by the Web site reduce costs, improve decision-making, and expand revenues by expanding the customer base. The Web site enables traditional charterers and owners to perform transactions online in an efficient and effective manner and provides access to the latest and most accurate industry information, thereby permitting users to make the best decisions and gather all their informational needs.
[0057] The principal functions performed by the Web site as described in more detail below are:
Online Ship and Barge Chartering Broker Portal Fixture Reports Position Lists Specific Trading Information Sub-portals—External Content Weather Industry News General News Terminal Leasing Services Agent Interface Inspection Services Interface Industry Tools Supporting Services
[0058] Online Ship and Barge Chartering
[0059] Introduction
[0060] The process of fixing a ship online is a central function of the Web site. The process links buyers (charterers) and sellers (ship owners) and streamlines their shared process of chartering a ship. Additional functionality, including linking other members of the value chain (suppliers, vendors, and other service providers) is discussed later.
[0061] The two primary constituents involved in the process of fixing a ship are the ship charterer (i.e. the buyer of the service) and the ship owner (i.e. the seller of the service). The other constituents (agents, inspection service providers, product suppliers, and terminal operators) are involved in the process but removed from the chartering process, and their role is described separately later.
[0062] Registration
[0063] The process of registering chartering principals (owners and charterers) gathers descriptive data about these participants (member companies) and then assigns rights to member companies which enable them to add users and levels. A potential user of the system can go to the Web site homepage, and obtain, fill out and obtain an online application. After verification by the Web site, the new user will then be assigned a user login/password.
[0064] User profile information submitted by users during the registration process is stored in a database accessible to the Web site server. Profiles for owners include static vessel information (updated periodically) and preferred business partners, including charterers, brokers, and agents. Profiles for charterers include preferred business partners, including owners, inspection companies, and terminalling companies. Other user specific preferences include terms and conditions, measurement (metric/US), and news feeds.
[0065] Entering Open Requirements and Positions
[0066] In order to conduct chartering of vessels online, there are two major groupings of information (open requirements and open positions) that are submitted into the system and updated when appropriate. The cargo requirements as posted and updated are them matched against the posted and updated vessel information (open positions) to identify a matching ship and cargo requirement To facilitate the entry of required and desired information, the charterer is presented with one or more validating forms which are used to submit the following information describing each new cargo:
Field Label Input Type Required? Indication Radio button Yes Firm Radio button Yes Load Area Drop down Discharge Area Drop down Load port Edit box Yes Discharge port Edit box Reference point Edit box Restrictions Edit box Cargo type Radio button Cargo name Drop down Cargo quantity Edit box Laycan start Calendar Lancan End Calendar Special requirements Edit box Confidential? Radio button Purge After Edit box Search for match Button
[0067] The shipowner is presented with one or more validating forms which are used to submit the following information describing each available vessel:
Field Label Input Type Required? Owner Drop down Yes Vessel name Drop down Yes Port open Drop down Yes DWT Edit box (auto populate) Yes Year built Edit Box (auto populate) Yes Cubic capacity Edit box (auto populate) Yes Cargo type (clean, dirty, both) Radio button Yes Last or Next Discharge Port: Area Drop down Yes Port Drop down No ETS LDP Calendar Yes Comments Edit box No Date Position Open Until Calendar No Add to list and match Check box Yes Submit Button Yes
[0068] To simplify the entry of open position information, the user may identify the vessel owner on whose behalf the entry is to be made. Then, the user will be presented with a drop down listing of all vessels associated with that owner. The user may then chose a vessel from this listing, or e for a listing of all vessels in the system. When a vessel name is entered, the data from the last open position entry made for that vessel will then be used to populate the Last or Next Discharge port fields. The user may then update the Last or Next Discharge fields with the new information. The prior Last Position and all associated Projected Positions will be cleared from the system and replaced by the new Open Position and associated Projected Positions.
[0069] Matching Engine (Chartering)
[0070] After a user enters and submits a cargo requirement or open vessel position, the search engine will find and display a “Results” page listing of all possible vessel matches for the cargo input.
[0071] The ship match is based on the following criteria:
[0072] 1. Cargo size/Ship size
[0073] 2. Cargo type/Ship's last cargo (compatibility)
[0074] 3. Cargo load dates/Laycan
[0075] 4. Load port/Position of ship (from reference point)
[0076] The “Results” page produced by the matching process preferably consists of a tabular listing containing the following information: RFO number, Ship name, Approvals, DWT, Cubic Capacity, Last Discharge Port, ETS Last Discharge Port, Last 3 cargoes, and Available until.
[0077] On the Results page, alongside each of the listed vessels, a check box may be displayed to identify the vessel(s) for which the charterer wishes to make an offer, or to identify the public cargo the vessel owner would like to make an offer to carry. Additional details for a specific vessel can be found by clicking onto the vessel name on the Results page, and the resulting display contains detailed ship information previously submitted by the shipowner. From the expanded ship details, the charterer will drill down onto the desired vessel and review the information.
[0078] If the charterer wishes to submit an offer for this vessel, he will press the “Submit Offer for this Vessel” button displayed on the vessel detail page.
[0079] Communication/Negotiation Engine (Chartering)
[0080] The Web site supports electronic communication (bid/counterbid) between owner and charterer. Once there is an agreement between the parties, the ship is placed on pending status, subject to the satisfaction of several conditions, which can be initiated by either party. This is the equivalent of the vessel being put on hold by the charterer so the ship owner can no longer negotiate another rate with other charterers. While the charterer can retract an offer with ease, the participating ship owner usually does not have that type of freedom.
[0081] As depicted in the flow chart seen in FIG. 2, before the chartering negotiation begins, the charterer and the ship owner have both supplied information to the registration database 201 during the registration process as indicated at 203 and 205 . The vessel owners submit descriptions of available vessel capacity as indicated at 206 , which are added to the open position file seen at 210 . When a new cargo description submitted by a charterer at 206 is compared by the matching engine 213 with the content of the open position file 210 to produce the result listing 215 . The negotiation process begins when the charterer reviews the result list and issues an RFO (Request For Offer) as seen at 217 .
[0082] The RFO is automatically constructed by the exchange server based on the information in the new cargo description submitted at 212 , the description of the matching open position posted at 207 , and selected information describing the charterer and the vessel owner obtained from the registration database 201 . The vessel owner is sent this information by email as seen at 220 and a new pending subject is created in the pending subject file 225 .
[0083] As seen at 230 , the vessel owner reviews the RFO and submits an offer which is posted in the pending subjects file 225 and sent by email to the charterer as seen at 232 .
[0084] The charterer reviews the offer received at 232 and then either ignores the offer (which terminates the negotiation), accepts the offer as made as indicated at 235 , or accepts the offer subject to stated exceptions as indicated at 237 .
[0085] If the charterer accepts the offer subject to exceptions, these exception conditions are communicated to the vessel owner as seen at 240 and are posted to the pending subject file.
[0086] If the original offer is accepted by the charterer at 235 , or is accepted subject to conditions which are then accepted by the vessel owner as seen at 250 , the pending subject as accepted is communicated to the charterer for final acceptance as seen at 260 . Once the charterer submits the final acceptance, the final subject is described in a recap message sent by email to both the vessel owner and the charterer as seen at 271 and 272 .
[0087] In addition to the foregoing exchange of information, the Web site also produces and distributes documentation designated as “Supplier Nomination of Vessel” and “Voyage Orders.” The Supplier Nomination and the Voyage Orders are initiated by the charterer or the operational department of the chartering organization and are sent to the supplier (e.g. the supplier of the petroleum, usually at the loadport) and to the ship owner.
[0088] Wireless Messaging
[0089] Because many users of the system travel frequently, it is important to provide mechanisms that will help insure that time-critical messages and notifications are delivered even when the intended recipient is away.
[0090] To support wireless messaging, when a new user first registers, they are asked to provide not only an email address and a conventional telephone number, but also a cell phone number, pager number, or access information that will permit a transmission to be made to another kind of WAP enabled device, such as a PDA. By identifying alternative contact information, messages and notifications can be communicated even when the user is not logged into the system or reachable at the user's normal primary email address or telephone number.
[0091] Even brief notification messages communicated via a pager or PDA can be used to advise a user that detailed information has been posted that deserves the user's attention and is available via the system Web site. The user who has received an email, pager or PDA notification will then have the option to log on to the system's “wireless site”, a customized front end version of our site for wireless devices which interacts the same way with the system's backend processes and database, but which presents and accepts information in a format (such as WML (Wireless Markup Language) which is compatible with the wireless device used to contact the wireless site. In this way, a user can continue a negotiation, contact inspection agencies, send message to another relevant user's cell phone, or even fix a ship over his wireless device.
[0092] By sending even a brief message which is compatible with the user's handheld wireless devices, key information can be made available when needed. For example, if a shipowner is playing golf on the golf course in London and the time a charterer issues an RFO reflecting a need for available capcity, the following message may be transmitted for display on the shipowner's cell phone:
Message from: Charterer Name: Joe Company: Repsol Cargo: Crude oil Laycan start date: 02/09/2001 Laycan end date: 02/22/2001 Discharge Area: Port of Spain Grade: 1 Click here for details
[0093] The shipowner can then use his cell phone to log onto the wireless site, access relevant information, and continue and close the negotiation. Similarly, a charterer who completes a negotiation on a wireless device can contact Inspectors and agents. Moreover, the wireless site will permit an inspector to do inventory management or enter details of a ship while he is inspecting it, using a PDA to exchange information with the system while the inspector is on-site.
[0094] Broker Portal
[0095] The Web site further provides information that ship chartering principals use to proceed with the chartering transaction. This information is preferably updated at least twice daily and serves as the informational baseline for principals use in transactions. The Web site organizes and presents relevant market information for each of the major trading regions in the world. This market information preferably include information regarding:
[0096] Ship fixtures
[0097] What ships were fixed and at what price
[0098] What ships pending, and not fixed
[0099] Position lists
[0100] Ship name, last discharge port, ets last discharge
[0101] Specific trading information—Analysis of regional markets and other information
[0102] Special market reports—Tanker news
[0103] Search facilities permit this information to be retrieved by region, vessel, and type of cargo
[0104] Sub-portals (3 rd Party Informational Services)
[0105] The Web site further implements interfaces to external sites that provide useful information and functionality to the ShipIQ.com user A sub-portal may be implemented as a click-through within a frame or as a separate browser window. In order to provide users to access to password protected sites, a Single Server Sign On procedure may be used to facilitate access to information from protected partner sites. In this way, when connecting to other sites, users will not need to log on a second time and may access data from external sites in a transparent process. External data which may be usefully made available includes:
[0106] Weather
[0107] Industry News (OPEC, environmental issues, tanker update)
[0108] General News
[0109] Agent Interface
[0110] The Web site preferably provides ship owners with the ability to access agent information from ports and nominate agents via email. Owners may nominate agents at the end of the chartering transaction by clicking on a form button to obtain a listing of all known agents at that load port. Upon choosing an agent, an email may then be automatically sent to that agent containing the required information regarding the completed transaction. The initial upload of the agent information will be performed by the Web site's editorial staff using the Web site's agent interface and updated whenever changes are made to the information.
[0111] Inspection Service Interface
[0112] In a similar manner, the Web site further provides the ability to nominate inspection companies to perform specified services. Upon completion of a chartering transaction, charterers can nominate inspection companies by pressing a button that retrieves up an inspection nomination form. This form is populated with data from the completed transaction completed and can be sent via email to the nominated company. After nominating an inspection company, the user will receive a notification that inspection nomination has been received and that service will be provided. Inspection companies conduct Quantity and Quality (Q and Q) inspection services and post inspection reports onto Web site database for access by customer. These inspection reports will be accessible to users of the Web site through secured access to database.
[0113] Terminal Leasing Interface
[0114] The Web site may also advantageously provide a terminal leasing interface that allows users to access tank availability status by terminalling company, geographic area, or terminal. Users will thus be able to locate available tank storage and associated information and contact and negotiate with terminalling companies. Automatic email facilities are provided to enable users to conveniently send email the terminalling company with requests for information.
[0115] Industry Tools
[0116] The Web site preferably provides access to a number of tools that will help the site user conduct valuable tasks. These services assist charterers and chartering managers in their daily tasks. These tools include:
[0117] A “Voyage Calculator” which produces distance tables and a profitability calculator
[0118] Currency Conversion Calculators (coupled to an external source of currency exchange rate data)
[0119] Demurrage Calculator (integrated from 3 rd party source)
[0120] Loss Control Monitoring (integrated from 3 rd party source)
[0121] Supporting or Infrastructure Services
[0122] Security. The integrity and security of data, both as stored in the Web site's database and as exchanged with users during transactions and other phases of the system's operation, should be assured through the use of available secure data storage and transmission mechanisms, and access to the data should be protected by a carefully administered system of user enrollment and update, password integrity and transaction reporting procedures.
[0123] Customer Service. The Web site should be further supported by other conventional methods including FAQ (Frequently Asked Questions) pages, demonstration pages, customer service telephone support, and email help desk support.
[0124] Conclusion
[0125] It is to be understood that the foregoing description is merely illustrative of one application of the principles of the invention. Numerous modifications may be made to the system described without departing from the true spirit and scope of the invention.
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An Internet based shipping marketplace is implemented by one or more Web database servers which permit charterers and ship owners to exchange information and make commitments relating to the transportation of goods. The marketplace stores information describing participating charterers, ship owners and service providers, some of which is gathered by registration procedures used when the participants initially use the marketplace. The marketplace implements the information distribution, matching, negotiation and documentation functions needed to form binding commitments that govern the shipment of cargoes by vessel owners on behalf of charterers. The shipping marketplace accepts and stores information from individual ship owners that identifies individual vessels and describes their current location and availability; and accepts from individual charterers cargo descriptions which include the loading and discharge locations of the route of a desired shipment of said particular cargo, and a specification of the time at which said desired shipment should occur.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to an oxide magnetic material usable for a multilayer inductor and a laminated ceramic substrate and the like in a high frequency circuit member and the like and its production method.
[0003] 2. Related Art
[0004] With the recent trend of miniaturization and use of higher frequency of electronic apparatus, a magnetic material usable in a high frequency band is more and more needed. As such a magnetic material for high frequency, NiCuZn-series spinel ferrites have been conventionally used, however in the case of frequency of several hundred MHz or higher, they cause natural resonance to result in increase of the loss and become incapable of practically working as magnetic materials. As a magnetic material usable up to a GHz band, hexagonal ferrites with high magnetic anisotropy defined as Ba 3 Me 2 Fe 24 O 42 (Me: a bivalent metal) and the like can be exemplified. Further, in order to improve the high frequency properties by improving the anisotropy, it is tried to replace some of Ba in the above-mentioned hexagonal type ferrites with Sr.
[0005] However, in the GHz band, the imaginary component (μ″) of the magnetic permeability becomes so significant as to increase the loss for use such ferrites for inductors.
[0006] Also, in a high frequency circuit member, use of a laminated ceramic substrate comprising a magnetic ceramic substrate and a dielectric ceramic substrate laminated on each other has been tried for miniaturization. With respect to such a laminated ceramic substrate, the patterned wiring of a capacitor is formed on a dielectric ceramic substrate and the patterned wiring of an inductor is formed on a magnetic ceramic substrate.
[0007] [0007]FIG. 4 is a perspective view showing one example of such a laminated ceramic substrate and FIG. 5 is an exploded perspective view. As illustrated in FIG. 4 and FIG. 5, the laminated ceramic substrate is composed by laminating a plurality of ceramic substrates 3 and 4 . A plurality of wiring patterns 11 composing inductors and capacitors are formed on the surfaces of the respective ceramic substrates 3 and 4 by a screen-printing method or the like.
[0008] In the case the ceramic substrates 3 are magnetic ceramic substrates and the ceramic substrates 4 are dielectric ceramic substrates, the wiring patterns 11 composing the inductors are formed on the magnetic ceramic substrates 3 and wiring patterns 11 composing the capacitors are formed on the dielectric ceramic substrates 4 . The wiring patterns 11 between the substrates are connected through via holes 12 .
[0009] After laminated, these ceramic substrates 3 and 4 are united by firing at a high temperature to obtain a laminated ceramic substrate.
[0010] In the case the wiring patterns 11 are formed by using Ag or the like with a high conductivity, it is required to carry out firing at a temperature as low as about 900° C. If firing is carried out at a high temperature, the shape of the wiring patterns of Ag or the like is deformed to make it impossible to form desired circuits on the respective substrates.
[0011] However, a conventional magnetic ceramic material like a hexagonal ferrite or the like has a suitable firing temperature of 1,300° C. or higher, and it has a problem that good magnetic properties cannot be obtained in the case firing is carried out at a temperature as low as about 900° C.
[0012] It has been tried to carry out firing at a low temperature by adding a sintering aid such as B 2 O 3 , CuO, and Bi 2 O 3 , neither sufficient effect on low temperature firing has been obtained yet nor the magnetic loss has been lowered sufficiently. Especially, with respect to a hexagonal ferrite in which some of Ba's are replaced with Sr's, any sufficient effect has not been obtained so far.
SUMMARY OF THE INVENTION
[0013] The object of the present invention is to provide an oxide magnetic material which can be produced by firing at a low temperature and has good magnetic properties in a high frequency band and its production method.
[0014] The oxide magnetic material of the invention is a Sr-containing oxide magnetic material having grain boundary phases in crystal grains, containing not less than 2% by weight of Sr in the grain boundaries and not less than 10% by weight of at least one element selected from Bi, V, B and Cu.
[0015] With respect to the oxide magnetic material of the invention, existence of not less than 2% by weight of Sr in the grain boundaries and not less than 10% by weight of the above-mentioned elements in the material can decrease the magnetic loss and give good magnetic properties. Further, the oxide magnetic material can be produced by firing at a low temperature.
[0016] The content of Sr in the grain boundary phases is preferably not less than 2% by weight, more preferably not less than 5% by weight and its upper limit is preferably not more than 30% by weight. When the content of Sr in the grain boundary phases is less than 2% by weight, shrinkage after firing at a temperature as low as about 900° C. is scarcely observed and a specimen after firing is unsatisfactory in the mechanical strength or the like and the magnetic loss is increased. On the other hand, if the Sr content exceeds 30% by weight, the content of other elements such as Bi and the like is relatively decreased, so that densification in the case of low temperature firing sometimes does not take place.
[0017] The content of the additive elements in the grain boundary phases is preferably not less than 10% by weight, more preferably not less than 25% by weight and its upper limit is not more than 70% by weight. If the content of additive elements is less than 10% by weight, shrinkage after firing at a temperature as low as about 900° C. is scarcely observed and a specimen after firing is unsatisfactory in the mechanical strength or the like and the magnetic loss is increased. On the other hand, if the content of additive elements exceeds 70% by weight, the magnetic permeability (a real component) decreases in some cases.
[0018] As for the additive elements, use of Bi is especially preferred. The additive elements may be contained in an oxide magnetic material by adding oxides containing the additive elements to a preliminarily baked powder obtained by preliminarily baking a raw material powder of the oxide magnetic material and firing the obtained mixture. The oxides containing the additive elements include Bi 2 O 3 , V 2 O 5 , B 2 O 3 , CuO, and the like. The content of the additive elements in the grain boundary phases can be adjusted by adjusting the amount of the oxides to be added to a preliminarily baked powder.
[0019] In the invention, together with the oxides containing additive elements, an oxide containing Sr may be added to the preliminarily baked powder and the obtained mixture may be fired to add Sr in the oxide magnetic material. Addition of the oxide containing Sr to the preliminarily baked powder increases the content of Sr especially in grain boundary phases. The content of Sr in the grain boundary phases can be also controlled by changing the pulverizing and mixing conditions at the time of pulverizing and mixing the preliminarily baked powder and the oxide containing Sr. For example, if the mixing is carried out for a long duration, the content of Sr in the grain boundary phases can be increased. Further, the content of Sr in the grain boundary phases can be controlled by changing the temperature at the time of preliminarily baking the raw material powder of the oxide magnetic material. That is, if the preliminarily baking temperature is decreased, the content of Sr in the grain boundary phases can be increased.
[0020] In the invention, Si may be contained further in the grain boundary phases. The content of Si in the grain boundary phases is preferably not less than 2% by weight, more preferably not less than 3% by weight and its upper limit is preferably not more than 20% by weight. Existence of Si in the grain boundary phases increases the shrinkage ratio of a fired oxide magnetic material and improves the magnetic properties. If the content of Si in the grain boundary phases is less than 2% by weight, the effect of Si-coated to suppress the loss is sometimes insufficient (that is, the value of μ′/μ″ becomes low). Meanwhile, if the content of Si exceeds 20% by weight, the value of permeability (the real component) tends to be significantly decreased.
[0021] Si can be contained in the grain boundary phases by adding an oxide containing Si together with oxides containing additive elements to the preliminarily baked powder of the oxide magnetic material and firing the resulting mixture. Incidentally, it is no need for Si in the grain boundary phases to exist evenly in the grain boundary phases but Si may exist unevenly in some portions of the grain boundary phases. For example, additive elements of such as Bi may exist more in some portions of the grain boundary phases, and Si may exist more in some other portions.
[0022] In the invention, the oxide magnetic material may contain a Group Ia element or a Group IIa element of a periodic table. Practical examples of the Group Ia element and the Group IIa element of a periodic table include Ca, K, Na, Sr, and Ba. Among them, Ca is preferable especially.
[0023] A Group Ia element or a Group IIa element can be contained in the oxide magnetic material by adding an additive, a compound of the Group Ia element or the Group IIa element with a Group VIIb element of a periodic table, together with oxides containing additive elements to the preliminarily baked powder of the oxide magnetic material and firing the resulting mixture.
[0024] The crystal grains of the oxide magnetic material of the invention preferably have an average grain diameter of 0.01 μm or large and 3 μm or smaller. The average grain diameter of the crystal grains can be measured from a cross-sectional photograph taken by a scanning electron microscope (SEM). More practically, it can be calculated by subjecting the cross-sectional photograph of a SEM to image processing to calculate the surface areas of the respective crystal grains and calculating the respective diameters of circles from them by assuming the crystal grains to be true circles. If the average crystal grain diameter is larger than 3 μm, shrinkage after firing at a temperature as low as about 900° C. is scarcely observed and a specimen after firing is unsatisfactory in the mechanical strength or the like and the magnetic loss is increased in some cases. On the other hand, if the average crystal grain diameter is minute, smaller than 0.01 μm, the crystal grains are easily agglomerated to make it difficult to obtain a slurry in which a magnetic material is evenly dispersed in some cases.
[0025] In the invention, the oxide magnetic material is preferably a hexagonal ferrite. Practically, the crystal grains are preferable to have a crystal structure of a hexagonal ferrite. It is further preferable for the hexagonal ferrite to have Z phase defined as M 3 Me 2 Fe 24 O 41 (M denotes Ba and/or Sr; and Me denotes a bivalent metal) as a main phase. Further, the main phase is preferably defined as (Sr x Ba 1-x ) 3 Me 2 Fe 24 O 41 (x is a value satisfying 0≦x≦1).
[0026] A production method of the invention is a production method capable of producing the above-mentioned oxide magnetic material of the invention and involves steps of preparing a preliminarily baked powder by preliminarily baking a raw material powder of an oxide magnetic material, preparing a mixed powder by mixing an oxide containing at least one additive element selected from Bi, V, B, and Cu with the preliminarily baked powder, and firing the mixed powder, and it is characterized that Sr is contained in grain boundary phases existing in the surrounding of the crystal grains of the resulting oxide magnetic material after firing.
[0027] As oxides containing the additive elements, those described above with respect to the foregoing oxide magnetic material of the invention can be used.
[0028] In the production method of the invention, together with the oxides containing the additive elements, an oxide containing Sr may be mixed with the preliminarily baked powder. The content of Sr in the grain boundary phases can be controlled by controlling the addition amount of the oxide containing Sr. Practically, the content of Sr in the grain boundary phases can be increased by increasing the addition amount.
[0029] In the production method of the invention, oxides containing additive elements and/or an oxide containing Sr is added to and mixed with the preliminarily baked powder and in this case, it is generally preferable to carry out the mixing while pulverization by a ball mill or the like being simultaneously carried out. At that time, the conditions for pulverization and mixing are controlled, so that the content of Sr in the grain boundary phases can be controlled. For example, if the mixing duration is prolonged, the content of Sr in the grain boundary phases can be increased.
[0030] Also, the content of Sr in the grain boundary phases can be controlled by controlling the temperature for the preliminary baking. Practically, by lowering the preliminary baking temperature is increased the content of Sr in the grain boundary phases.
[0031] Further, in the production method of the invention, together with the oxides containing additive elements, an oxide containing Si may be mixed with the preliminarily baked powder. Si can be contained in the grain boundary phases by mixing the oxide containing Si with the preliminarily baked powder.
[0032] Also, in the production method of the invention, together with the oxides containing additive elements, an additive, a compound of the Group Ia element or the Group IIa element with a Group VIIb element, may be added to the preliminarily baked powder of the oxide magnetic material. Addition of such an additive to the preliminarily baked powder makes the Group Ia element of the Group IIa element contained in the oxide magnetic material.
[0033] The melting point of the additive is preferably 900° C. or lower. Practical examples of the additive with a melting point of 900° C. or lower include CaCl 2 (melting point of 772° C.), KF (melting point of 830° C.), KI (melting point of 723° C.), NaCl (melting point of 800° C.), NaI (melting point of 651° C.), SrBr 2 (melting point of 643° C.), SrCl 2 (melting point of 873° C.), BaBr 2 (melting point of 847° C.), BaI 2 (melting point of 740° C.), and the like. Among them, CaCl 2 is preferable to be used especially.
[0034] The addition amount of the additive is preferably not more than 25% by weight in the preliminarily baked powder. That is, the amount is preferably 33.3 part by weight to 100 part by weight of the preliminarily baked powder. If the addition amount of the additive exceeds 25% by weight, the ratio of the magnetic ceramic material is relatively decreased so that the magnetic properties tend to be deteriorated. The addition amount of the additive is further preferably 0.05 to 25% by weight, furthermore preferably 0.05 to 1% by weight. If the addition amount of the additive is too low, any sufficient effect to provide good magnetic properties by low temperature firing cannot be obtained in some cases.
[0035] In the production method of the invention, the mixed powder can be fired after being formed into a substrate-like shape. Accordingly, a magnetic substrate can be produced. As a method to be employed for forming the mixed powder into the substrate-like shape, a method involving adding a binder to the mixed powder, producing a slurry of the resulting powder mixture, and forming a green sheet from the slurry can be exemplified. Further, after a binder is added to the mixed powder, the resulting powder mixture may be press-formed to make the substrate-like shape.
[0036] After the green sheet formed into the substrate-like shape is laminated on a substrate-like green sheet produced from another material such as a dielectric material or the like, the obtained laminated body may be fired. Consequently, a laminated ceramic substrate comprising the magnetic substrate and a substrate made of another material such as a dielectric can be obtained.
[0037] Wiring patterns can be formed by a screen-printing method or the like on the substrate-like green bodies before firing. Further, via holes and the like can be formed, too.
[0038] Since the oxide magnetic material of the invention can be fired at a low firing temperature, a material such as Ag can be used as a material for wiring patterns.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] [0039]FIG. 1 is a graph showing μ′/μ″ of an example according to the invention.
[0040] [0040]FIG. 2 is a graph showing μQ of an example according to the invention.
[0041] [0041]FIG. 3 is a scanning electronic microscopic photograph of a cross-section of an oxide magnetic material of Example 2 according to the invention.
[0042] [0042]FIG. 4 is a perspective view showing one example of a laminated ceramic substrate.
[0043] [0043]FIG. 5 is an exploded perspective view showing one example of a laminated ceramic substrate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] Hereinafter, the invention will be described along with practical examples, however the invention is not limited to the following examples.
EXAMPLES 1 to 5
[0045] Using BaO, SrO, CoO, and Fe 2 O 3 as raw material powders, the respective raw material powders were weighed so as to adjust the Sr replacement ratio x to be x=0, x=0.25, x=0.5, x=0.75, and x=1 in the following stoichiometric composition; (Sr x Ba 1-x ) 3 Co 2 Fe 24 O 41 and the weighed raw material powders were mixed while being pulverized by a ball mill comprising a pot and balls made of zirconia for 24 hours. The obtained mixed powders were preliminarily baked at 1,250° C. (in the case x=0, at 1,300° C.) for 2 hours to obtain primarily baked powders of hexagonal ferrites with the Z-type structure defines as (Sr x Ba 1-x ) 3 Co 2 Fe 24 O 41 (x=0, x=0.25, x=0.5, x=0.75, or x=1).
[0046] After 5 part by weight of a Bi 2 O 3 powder and 1 part by weight of a SrO powder were added to 96 part by weight of each obtained preliminarily baked powder, the resulting powder mixture was mixed while being pulverized by a ball mill comprising a pot and balls made of zirconia. To each obtained mixed powder were added an organic solvent and a PVA-based binder and again wet mixing was carried out by a ball mill. The PVA-based binder was added so as to be in an amount of 5% by weight.
[0047] After the wet mixing, each powder obtained through drying and classifying steps was formed into a ring-like shape with an outer diameter of 8 mm, an inner diameter of 4 mm and a height of 2 mm. The obtained body was fired at 900° C. for 2 hours. Each obtained ring-like specimen was subjected to permeability measurement using an impedance analyzer.
[0048] Example 1, Example 2, Example 3, Example 4, and Example 5 were those with the Sr replacement ratio controlled to be as x=1, x=0.25, x=0.5, x=0.75, and x=1, respectively.
COMPARATIVE EXAMPLES 1 AND 2
[0049] A ring-like specimen of Comparative Example 1 was produced in the same manner as Example 2, except that no SrO but only 5 part by weight of Bi 2 O 3 was added to the preliminarily baked powder obtained by preliminary baking at 1,300° C.
[0050] A ring-like specimen of Comparative Example 2 was produced in the same manner as Example 3, except that no SrO but only 5 part by weight of Bi 2 O 3 was added to the preliminarily baked powder obtained by preliminary baking at 1,300° C.
[0051] These obtained ring-like specimens were subjected to permeability measurement similarly to those of the foregoing Examples.
[0052] [0052]FIG. 1 and FIG. 2 show graphs showing the results of the permeability measurement of the respective ring-like specimens.
[0053] [0053]FIG. 1 is a graph showing the relation between the Sr replacement ratio and the ratio μ′/μ″ (=Q) of the real component μ′ and the imaginary component (μ″) at 1.8 GHz. FIG. 2 is a graph showing the product (μQ) of the real component μ′ of the permeability and Q at 1.8 GHz. In FIG. 1 and FIG. 2, the marks show Examples 1 to 5 and the marks show Comparative Examples 1 and 2.
[0054] As it is made clear from FIG. 1 and FIG. 2, Examples 1 to 5 were found having higher μ′/μ″ than that of Comparative Examples 1 and 2 and showing the lowering of magnetic loss. In addition, Examples 1 to 5 were also found having higher μ′/μ″ in μQ than that of Comparative Examples 1 and 2, showing better inductance properties.
[0055] [0055]FIG. 3 is a scanning electron microscopic (SEM) photograph showing a cross-section of the ring-like specimen of Example 2. In FIG. 3, the portions seen relatively white and bright show grain boundary phases and the portions seen relatively black and dark show crystal grains. Incidentally, the average grain diameter of the crystal grains of Example 2 was found to be 0.6 μm by measurement. The average grain diameter of the crystal grains of Comparative Example 1 was found to be 4.5 μm.
[0056] The contents of Bi and Sr contained in the grain boundary phases were measured by EPMA. The measurement results are shown in Table 1. With respect to other Examples and Comparative Examples, the contents of Bi and Sr contained in the grain boundary phases were measured in a similar manner. The measurement results are shown in Table 1.
TABLE 1 Sr Content (% by weight) Bi Content (% by weight) Ex. 1 6 39 Ex. 2 8 35 Ex. 3 9 34 Ex. 4 11 34 Ex. 5 13 33 Comp. Ex. 1 <1 43 Comp. Ex. 2 1 41
[0057] As being made clear from Table 1, with respect to Examples 1 to 5 according to the invention, Sr was found existing in a high concentration in the grain boundary phases.
[0058] Further, it was found that Bi and Sr existed in form of oxides in the grain boundary phases by XPS.
EXAMPLE 6
[0059] Using a slurry after adding and mixing the binder in Example 2 was formed a green sheet by a doctor blade method. Patterning of a Ag paste was carried out on the green sheet by a screen-printing method to form a desired passive circuit. Other green sheets in which different passive circuits were similarly formed were produced and 10 sheets of such green sheets were laminated and press-bonded by a hydroisostatic press and fired at 900° C. to obtain a multilayer inductor. The obtained multilayer inductor was found having good sintered state.
[0060] Further, green sheets of a dielectric material were produced and on the green sheets were similarly layered green sheets made of the above-mentioned oxide magnetic materials of the invention and the respective layered bodies were press-bonded similarly and fired at 900° C. to obtain multilayer inductors. The obtained multilayer inductors were found having good sintered state.
EXAMPLES 7 to 9
[0061] After Bi 2 O 3 , SrO, and SiO 2 were added at the ratios shown in Table 2 to 96 part by weight of preliminarily fired powders obtained in the same manner as Example 2 and ring-like specimens were produced in the same manner as the foregoing Examples.
TABLE 2 Bi 2 O 3 SrO SiO 2 Ex. 7 5 part by weight 1 part by weight 0.5 part by weight Ex. 8 5 part by weight 1 part by weight 1.0 part by weight Ex. 9 5 part by weight 1 part by weight 1.5 part by weight
[0062] The contents of Bi, Sr, and Si contained in the grain boundary phases in the respective specimens of Examples 7 to 9 were measured in the same manner as the foregoing Examples and the results of the measurement are shown in Table 3.
TABLE 3 Sr Content Bi Content Si Content (% by weight) (% by weight) (% by weight) Ex. 7 7 33 3 Ex. 8 7 30 6 Ex. 9 6 27 10
[0063] Similarly to the foregoing Examples, the permeability of each specimen of Examples 7 to 9 was measured and the results of the measurement are shown in Table 4. Further, the shrinkage ratios before and after firing were measured and shown in Table 4. The shrinkage ratios were calculated by measuring the size before firing and the size after firing. Table 4 shows the results of Example 2 and Comparative Example 1 together.
TABLE 4 Shrinkage Ratio (%) μ′/μ″ (1.8 GHz) μQ (1.8 GHz) Ex. 7 9.6 5.64 10.87 Ex. 8 12.3 7.49 11.46 Ex. 9 13.1 9.33 15.45 Ex. 2 9.0 3.32 10.17 Comp. Ex. 1 0 1.85 5.64
[0064] As being made clear from the results shown in Table 4, existence of SiO 2 in the grain boundary phases, it was found that the shrinkage ratio at the time of firing was increased and the magnetic properties were also improved. Incidentally, with respect to the oxide magnetic materials of the invention, a Group Ia element or a Group IIa element of a periodic table may be contained. Addition of such an element gives further preferable magnetic properties and makes it possible to carry out firing at a lowered temperature. Such an element can be added in the oxide magnetic materials by adding an additive, a compound of a Group VIIb element with a Group Ia element or a Group IIa element, to oxide magnetic materials.
[0065] As the foregoing compound, those having a melting point of 900° C. or lower are preferable to be employed. Practical examples of the foregoing compounds a melting point of 900° C. or lower include CaCl 2 , KF, KI, NaCl, NaI, SrBr 2 , SrCl 2 , BaBr 2 , BaI 2 , and the like. Among them, CaCl 2 is preferable to be used especially.
EXAMPLE 10
[0066] As raw material powders were used 6.77 part by weight of a SrO powder, 10.02 part by weight of a BaO powder, 6.53 part by weight of a CoO powder, and 83.46 part by weight of a Fe 2 O 3 powder and they are mixed while being pulverized by a ball mill comprising a pot and balls made of zirconia for 24 hours. The obtained mixed powder was preliminarily baked at 1,250° C. for 2 hours to obtain a primarily baked powder of a hexagonal ferrite with the Z-type structure defines as Sr 1.5 Ba 1.5 Co 2 Fe 24 O 41 .
[0067] After 5 part by weight of a Bi 2 O 3 powder, 1 part by weight of a SrO powder, and 0.1 part by weight of a CaCl 2 powder were added to 93.9 part by weight of the obtained preliminarily baked powder, the resulting powder mixture was mixed again by a ball mill. The obtained mixed powder was press-formed in a ring-like shape and the resulting green body was fired at 900° C. for 2 hours.
[0068] The ratio μ′/μ″ of the obtained ring-like specimen at 1.8 GHz was 3.74 and μQ at 1.8 GHz was 13.27. Further, the Sr content in the grain boundary phases was 9% by weight and the Bi content was 34% by weight.
[0069] According to the invention, an oxide magnetic material can be produced by low temperature firing and is provided with good magnetic properties in a high frequency band.
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An oxide magnetic material of the invention is an oxide magnetic material of a hexagonal ferrite containing Sr, has grain boundary phases in the surrounding of the crystal grains, contains not less than 2% by weight, preferably not less than 5% by weight, of Sr in the grain boundary phases and not less than 10% by weight, preferably not less than 25% by weight, of at least one additive element selected from Bi, V, B and Cu.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of co-pending U.S. patent application Ser. No. 11/288,976, filed on Jan. 29, 2005; which is a continuation of U.S. patent application Ser. No. 10/738,950, filed on Dec. 17, 2003, now U.S. Pat. No. 7,021,374; which is a continuation of U.S. patent application Ser. No. 10/354,226, filed on Jan. 29, 2003, now U.S. Pat. No. 6,688,398; which is a continuation of U.S. patent application Ser. No. 09/762,698, filed on May 10, 2001, now issued U.S. Pat. No. 6,527,047, issued Mar. 4, 2003; which claims priority to PCT/GB99/02704, filed on Aug. 16, 1999; which claims benefit of GB 9818366.8 filed Aug. 24, 1998, filed in Great Britain. Each of the aforementioned related patent applications is herein incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a method and apparatus for facilitating the connection of tubulars using a top drive and is, more particularly but not exclusively, for facilitating the connection of a section or stand of casing to a string or casing.
[0004] 2. Description of the Related Art
[0005] In the construction of wells such as oil or gas wells, it is usually necessary to line predrilled holes with a string of tubulars known as casing. Because of the size of the casing required, sections or stands of say two sections of casing are connected to each other as they are lowered into the well from a platform. The first section or stand of casing is lowered into the well and is usually restrained from falling into the well by a spider located in the plafform's floor. Subsequent sections or stands of casing are moved from a rack to the well centre above the spider. The threaded pin of the section or stand of casing to be connected is located over the threaded box of the casing in the well to form a string of casing. The connection is made-up by rotation therebetween.
[0006] It is common practice to use a power tong to torque the connection up to a predetermined torque in order to perfect the connection. The power tong is located on the platform, either on rails, or hung from a derrick on a chain. However, it has recently been proposed to use a top drive for making such connection.
[0007] Prior to the present invention, pipe handling devices moved pipes to be connected to a tubular string from a rack to the well centre using articulated arms or, more commonly, a pipe elevator suspended from the drilling tower.
[0008] The present invention provides an alternative to these devices.
SUMMARY OF THE INVENTION
[0009] Accordingly, a first aspect of the present invention provides an apparatus for facilitating the connection of tubulars, said apparatus comprising a winch, at least one wire line and a device for gripping a tubular the arrangement being such that, in use, the winch can be used to winch said at least one wire and said device to position a tubular below said top drive.
[0010] Further features are set out in claims 2 to 6 .
[0011] According to a second aspect of the present invention there is provided a method of facilitating the connection of tubulars using a top drive and comprising the steps of attaching at least one wire to a tubular, the wire depending from the top drive or from a component attached thereto, and winching the wire and the tubular upwards to a position beneath the top drive.
[0012] According to a third aspect of the present invention there is provided an apparatus for facilitating the connection of tubulars using a top drive, said apparatus comprising an elevator and a pair of bails, characterized in that said elevator is, in use, movable in relation to said pair of bails.
[0013] According to a fourth aspect of the present invention there is provided: an apparatus for facilitating the connection of tubulars using a top drive, said apparatus comprising an elevator and a pair of bails, characterized in that said elevator is, in use, movable relative to said pair of bails.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a better understanding of the present invention and in order to show how the same may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:
[0015] FIGS. 1 a to 1 e are perspective views of an apparatus in accordance with a first embodiment of the present invention at various stages of operation; and
[0016] FIGS. 2 a to 2 d are perspective views of an apparatus in accordance with a second embodiment of the invention at various stages of operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Referring to FIGS. 1 a to 1 e there is shown an apparatus which is generally identified by reference numeral 1 .
[0018] The apparatus 1 comprises a clamp 2 for retaining a tubular 3 . The clamp 2 is suspended on wires 4 , 5 which are connected thereto on opposing sides thereof. The wire 5 passes through an eye 6 in lug 7 which is attached to a spherical bearing in arm 8 of a suspension unit 9 at the point at which the arm 8 is connected to a hydraulic motor. The wire is connected to the hydraulic motor 10 in a corresponding manner. The suspension unit 9 is of a type which enables displacement of the tubular 3 when connected to a tool 17 (see below), relative to a top drive 13 , along a number of different axes. The wires 4 , 5 pass across the suspension unit 9 and over pulley wheels 11 which are rotatably arranged on a plate 12 . The plate 12 is fixed in relation to a top drive generally identified by reference numeral 13 . The wires 4 , 5 then pass over drums 14 to which the wires 4 , 5 are also connected. The drums 14 are rotatable via a hydraulic winch motor 15 .
[0019] In use, the clamp 2 is placed around a tubular below a box 16 thereof. The hydraulic winch motor 15 is then activated, which lifts the tubular 3 (conveniently from a rack) and towards a tool 17 for gripping the tubular 3 ( FIG. 1 b ). The tubular 3 encompasses the tool 17 at which point the hydraulic winch motor 15 is deactivated ( FIG. 1 c ). During this operation the elevator 18 is held away from the tool 17 by piston and cylinders 19 , 20 acting on bails 21 and 22 . The suspension unit 9 allows the hydraulic motor 10 and the arrangement depending therebelow to move in vertical and horizontal planes relative to the top drive 13 . The eyes 6 in lugs 7 maintain the wires 4 and 5 in line with the tubular 3 during any such movement. The tool 17 may now be used to connect the tubular to the tubular string. More particularly, the tool may be of a type which is inserted into the upper end of the tubular, with gripping elements of the tool being radially displaceable for engagement with the inner wall of the tubular so as to secure the tubular to the tool. Once the tool is secured to the tubular, the hydraulic motor 10 is activated which rotates the tool 17 and hence the tubular 3 for engagement with a tubular string held in a spider.
[0020] The clamp 2 is now released from the tubular 3 , and the top drive 13 and hence apparatus 1 is now lifted clear of the tubular 3 . The elevator 18 is now swung in line with the apparatus 1 by actuation of the piston and cylinders 19 and 20 ( FIG. 1 d ).
[0021] The top drive 13 is then lowered, lowering the elevator 18 over the box 16 of the tubular 3 . The slips in the elevator 18 are then set to take the weight of the entire tubular string. The top drive is then raised slightly to enable the slips in the spider to be released and the top drive is then lowered to introduce the tubular string into the borehole.
[0022] Referring to FIGS. 2 a to 2 d there is shown an apparatus which is generally identified by reference numeral 101 .
[0023] The apparatus 101 comprises an elevator 102 arranged at one end of bails 103 , 104 . The bails 103 , 104 are movably attached to a top drive 105 via axles 106 which are located in eyes 107 in the other end of the bails 103 , 104 . Piston and cylinders 108 , 109 are arranged between the top drive 105 and the bails. One end of the piston and cylinders 108 , 109 are movably arranged on axles 110 on the top drive. The other end of the piston and cylinders 108 , 109 are movably arranged on axles 111 , 112 which are located in lugs 113 , 114 located approximately one-third along the length of the bails 103 , 109 .
[0024] The elevator 102 is provided with pins 115 on either side thereof and projecting therefrom. The pins 115 are located in slots 116 and 116 g . A piston 117 , 118 and cylinder 119 , 120 are arranged in each of the bails 103 , 104 . The cylinders are arranged in slot 121 , 122 . The piston 117 , 118 are connected at their ends to the pins 115 . The cylinders 119 , 120 are prevented from moving along the bails 103 , 104 by cross members 123 and 124 . A hole is provided in each of the cross members to allow the pistons to move therethrough.
[0025] In use, a tubular 125 is angled from a rack near to the well centre. The tubular may however remain upright in the rack. The clamp 102 is placed around the tubular below a box 126 ( FIG. 2 a ). The top drive is raised on a track on a derrick. The tubular is lifted from the rack and the tubular swings to hang vertically ( FIG. 2 b ). The piston and cylinders 108 , 109 are actuated, extending the pistons allowing the bails 103 , 104 to move to a vertical position. The tubular 125 is now directly beneath a tool 127 for internally gripping and rotating the tubular 125 ( FIG. 2 c ). The pistons 117 , 118 and cylinders 119 , 120 are now actuated. The pins 115 follow slot 116 and the clamp 102 moves upwardly, lifting the tubular 125 over the tool 127 ( FIG. 2 d ). The tool 127 can now be actuated to grip the tubular 125 .
[0026] At this stage the elevator 102 is released and the top drive 105 lowered to enable the tubular 125 to be connected to the string of tubulars in the slips and torqued appropriately by the top drive 105 .
[0027] The pistons 117 , 118 and cylinders 119 , 120 are meantime extended so that after the tubular 125 has been connected the top drive 105 can be raised until the elevator 102 is immediately below the box. The elevator 102 is then actuated to grip the tubular 125 firmly. The top drive 105 is then raised to lift the tubular string sufficiently to enable the wedges in the slips to be withdrawn. The top drive 105 is then lower to the drilling platform, the slips applied, the elevator 102 raised for the tubular 125 and the process repeated.
[0028] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
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An apparatus for facilitating the connection of tubulars, said apparatus comprising a winch, at least one wire line, and a device for gripping the tubular, the arrangement being such that, in use, the winch can be used to winch said at least one wire and said device to position a tubular below said top drive.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of erasure of x-ray images in such a manner as to eliminate the non-uniformities or ghosts arising from a previous image. More particularly, the invention relates to a method of erasure of an x-ray imaging device which uses high bias voltage during the image capture process.
2. Brief Description of the Prior Art
It is well known to use light to erase an image remaining on an x-ray plate. This is done for x-ray plates which use a stimulable phosphor medium as disclosed, for example, in U.S. Pat. No. 5,371,377 of Dec. 6, 1994, where light containing two distinct or separate emission bands is employed. This is also done for x-ray image capture panels where the photoconductive layer is made of a material such as amorphous selenium, lead oxide, thallium bromide, cadmium telluride, and the like which directly capture radiographic images as patterns of electrical charges, and where a high bias voltage is applied during the image capture process. Such a method is disclosed, for example, in U.S. Pat. No. 5,563,421 of Oct. 8, 1996 in conjunction with a special image capture panel, wherein the radiation sensitive layer is exposed to two uniform patterns of light, one after the other, in order to substantially eliminate residual electrical charges remaining in the photoconductive layer.
As mentioned in this U.S. Pat. No. 5,563,421, such electrical charges have also been minimized by the application of a reversed and decreasing electric field, however this involves multiple applications of such field.
Despite these various procedures, it has been found that non-uniformities or ghosts arising from a previous image still often remain on the x-ray imaging device.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for erasure of an x-ray imaging device so as to completely or essentially completely eliminate the non-uniformities or ghosts arising from a previous image.
A further object of the invention is to achieve such erasure in a simple, efficient and inexpensive manner.
Other objects and advantages of the invention will be apparent from the following description thereof.
In essence, it has been surprisingly found that erasure of an x-ray imaging device, where a previous image has been obtained with application of a high voltage bias during the imaging process, can be significantly improved by also applying a high voltage bias to the x-ray imaging device when exposing the device to erasing light. Once erasure is complete, the high voltage is turned off before turning off the light. It is preferable, although not essential, to use the same magnitude of high voltage bias during imaging as during erasure.
The x-ray imaging device that may be treated in accordance with the novel process will normally comprise a plate of a photoconductive material overcoated with a layer of a dielectric material. The photoconductive material may, for example, be amorphous selenium, lead oxide, cadmium sulphide, cadmium telluride, thallium bromide, mercuric iodide or similar materials which are suitable for x-ray imaging while applying high voltage bias. The dielectric material may be any suitable dielectric for such purposes, for example, parylene, polycarbonate, polyester and the like. In addition, as is known in the art, the x-ray imaging device is provided with a substrate on which the photoconductive plate is mounted. Such substrate may consist of any suitable material such as aluminum, ITO coated glass, a thin film transistor array (TFT), and the like. Finally, over the dielectric layer there is normally provided a thin layer of a conductive material which acts as the biasing electrode, it may be selected from gold, platinum, aluminum, chromium, indium tin oxide (ITO) or the like.
When an x-ray imaging device such as described above is used for imaging, it is normally positively biased and charges (electron-hole pairs) that are generated from x-ray absorbtion by the photoconductor will move under the applied electric field. Negative charges will move in the direction of the top positive electrode and will stop and accumulate at the photoconductor-dielectric interface. When erasure of such device takes place for subsequent re-use, a ghost will usually remain due to a non-uniform charge accumulation at the interface between the photoconductive plate and the dielectric layer. This non-uniform charge accumulation causes a non-uniform sensitivity within the x-ray imaging device that produces the ghost.
One way to eliminate such non-uniformity and ghosts is by uniformizing the charges at the interface. This is achieved by subjecting the x-ray imaging device simultaneously to a positive high voltage and to an erasing light and then turning off the voltage and thereafter the light. The sensitivity of the plate will be somewhat lower with this operation, but it will be uniform within the plate, allowing for the elimination of the ghosts.
If it is desired to keep the sensitivity high and in addition to uniformize the same, one can completely or essentially completely eliminate the negative charges at the interface by switching the high voltage from positive to negative polarity during the erasure process. This produces an essentially complete neutralization of the charges, provided the duration of the negative voltage is such that the number of positive charges generated to neutralize the negative charges at the interface is essentially equal to the number of said negative charges. If the duration of the negative voltage bias is exceeded, this may lead to an accumulation of positive charges at the interface which, if not corrected, could cause a large dark current to flow during the image capture process of the next reference frame. This, however, can be corrected by applying a positive voltage bias to the device without application of the light so as to stabilize the dark current. Thereafter, the imaging of the next reference frame can be safely performed.
When reference is made herein to high erasure voltage, it usually means a voltage of several thousand volts, for example, between 3000 V and 10,000 V for the positive voltage and between -100 V and -10,000 V for the negative voltage. The voltage employed will generally depend on the thickness of the photoconductor plate. The thicker the plate, the higher the voltage. The light used for erasure will normally have a spectral emission of 400-800 nm, preferably 450-600 nm, and a luminance of 5-500 cd/m 2 , preferably 20-100 cd/m 2 . Also, when it is stated that the ghosts are eliminated, this means that they are essentially not visible within the noise floor of a normal x-ray imaging system.
The invention, therefore, resides in the discovery that ghosts can be eliminated by erasing x-ray imaging devices with light (as this is usually done), but in the presence of high voltage, the polarity of which may be reversed during the erasure process to achieve essentially complete neutralization of the charges when this is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention will now be further described with reference to the appended drawings in which:
FIG. 1 is a cross-sectional enlarged view of an x-ray imaging device suitable for erasure in accordance with the present invention;
FIG. 2 illustrates an image frame charge distribution after x-ray exposure;
FIG. 3 illustrates a reference frame charge distribution after erasure with light alone according to the prior art.
FIG. 4 is a view in perspective of an x-ray imaging arrangement also showing a linescan profile produced within the imaging x-ray plate.
FIG. 5 is a graph that shows a ghost appearing when a second image was taken after erasure in accordance with the prior art;
FIG. 6 illustrates one embodiment of the erasure method of the present invention;
FIG. 7 is a graph that shows no ghost appeared when a second image was taken after erasure pursuant to the embodiment of FIG. 6;
FIG. 8 illustrates another embodiment of the erasure method of the present invention;
FIG. 9 illustrates an alternative embodiment to FIG. 8; and
FIG. 10 is a graph showing that no ghost appeared when a second image was taken after erasure pursuant to the embodiment of FIG. 8 or FIG. 9.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates an arrangement of an x-ray imaging device which is suitable for erasure in accordance with this invention. In this figure the x-ray imaging device 11 comprises a plate 12 of a photoconductive material, such as amorphous selenium, which is overcoated with a layer 14 of dielectric material, such as parylene. Plate 12 which may, for example, be 500 μm thick, is mounted on substrate 16 which, for example, can be made of ITO coated glass or TFT. on top of dielectric layer 14 which may, for example, be 40 μm thick, there is provided a conductive electrode 18 made, for instance, of ITO. The bias voltage is provided by the electrical set-up 20 illustrated schematically in this figure. This set-up 20 imparts the required high voltage during the imaging process, as well as during its erasure in accordance with the present invention. It should be noted that in all figures the same reference numbers are used to show the same elements.
During the imaging process, the charges are unevenly distributed as illustrated in FIG. 2. Due to the dielectric parylene layer 14, charges that are generated from the absorption of x-rays 15 and which move under applied electric field supplied by the set-up 20 will stop at the selenium-parylene interface 22. The negative charges accumulate at this interface 22 and contribute to reduce the electric field in the selenium layer on the next image frame. Only the area where the target-object 17 is located keeps an unchanged sensitivity. On the next image frame (after erasure with light alone) as shown in FIG. 3, this results in a more effective discharge on the area where the sensitivity is higher, i.e. where the target-object 17 was located in the previous image frame. This phenomenon is believed to explain the ghost effect observed when only light is used to erase the previous image. This is further illustrated in FIG. 4 where an x-ray imaging device 11 is shown in perspective. When the target-object 17 is placed on top of the conductive electrode 18 and a suitable electric field is applied, x-rays 15 will be absorbed by the photoconductive plate 12 which is mounted on substrate 16 and overcoated with dielectric layer 14. The linescan profile 19 resulting from such operation is reproduced within the broken-line frame shown under the device 11. There is an elevation 19A in this profile under the area where the target-object 17 is located, showing the variation of relative signal strength in that area.
FIG. 5 shows two such linescans where after erasure of Image 1 using light alone as shown in FIG. 3, a new Image 2 is taken where the ghost effect observed is a reversed image of a preceding image on the actual image display. The ghost appears at the moment the actual image is taken so there is no possibility to get rid of it by a substraction operation of the reference frame. It is obvious that such ghosts are not acceptable in a medical diagnostic perspective. It should be noted that the linescans constitute a plot of a relative signal strength versus position of the target-object. The relative signal strength can be related, as is known, to the voltage, the electric charge, the grey scale and the like.
FIG. 6 illustrates one embodiment of the method of the present invention where the ghost is eliminated by uniformizing and decreasing the number of charges at the interface 22. At point (A) of this figure there is shown the distribution of charges right after image formation by absorbtion of x-rays 15. Only the area where the target 17 was has an unchanged sensitivity, namely no negative charges at the interface 22. In order to proceed with the erasure of this device, a high positive voltage is turned on and then the erasing light 21 is turned on. This produces the charge distribution shown at point (B) wherein the number of charges at the interface 22 is uniform within the plate 12. At point (C) of FIG. 6 there is shown a charge distribution after the high voltage has been turned off while the light 21 is still applied to reduce the number of charges in the device. Then the light 21 is also turned off. There are still some negative charges remaining at the interface 22, which will reduce the sensitivity.
FIG. 7 shows the result obtained from the method used according to FIG. 6. It shows the plot of relative signal strength as a function of position for the first and second images taken, where Image 2 was taken after erasure of Image 1 by the method described above in conjunction with FIG. 6. FIG. 7 shows that unlike the result shown in FIG. 5, in this case there is no ghost visible.
Another embodiment of the erasure method of the present invention is illustrated in FIG. 8. Here, the distribution of the charges at point (A) is identical to the one shown in FIG. 6, i.e. it shows such distribution right after the image frame and only the area where the target was has an unchanged sensitivity without any negative charges at the interface 22. This device is erased by turning on a high positive voltage by set-up 20 and then turning on the light 21, thereby uniformizing the interface 22 as shown at point (B). However, in addition to this, the high voltage is switched from positive to negative polarity during the erasure operation for just long enough to neutralize the negative charges at the interface 22. This is followed by turning the high voltage off and then turning the light off. The resulting charge distribution is shown a point (C) of FIG. 8. This results in very few negative charges being left at the interface 22 which is a highly desirable effect.
In FIG. 9 an alternative to the embodiment of FIG. 8 is illustrated. Here, the operations at points (A) and (B) are identical to those shown in FIG. 8. However, at point (C) the negative polarity voltage is maintained for a longer period of time than in FIG. 8 which produces accumulation of positive charges at interface 22. This, if left as such, would cause a large dark current to flow on the next reference frame which would not be satisfactory. In order to stabilize the dark current by removing the positive charges, the device is subjected to a high positive voltage bias without application of light as shown at point (D) of FIG. 9, before the next reference frame. This produces again a very satisfactory erasure of the x-ray device. The arrangement of FIG. 9 does not require as close a timing control for negative voltage bias as is required pursuant to FIG. 8.
As far as timing of high voltage and light is concerned, it can be readily determined for various situations, such as the thickness of the photoreceptor, the luminance of light, etc. A person skilled in the art will determine and optimize such timing for any particular operation. However, to give an example of appropriate timings the following is suggested.
If Δt 1 is the delay during which positive high voltage (PHV) is on before light is switched on;
Δt 2 is the time during which PHV is on while light is also on;
Δt 3 is the time during which negative high voltage (NHV) is on, when it is used; and
Δt 4 is the delay during which the light remains on after high voltage is switched off.
Then suitable time ranges for the above situations could be as follows:
______________________________________Δt.sub.1 = 0-10 sec (if 0 then both the PHV and light are switched on simultaneously) Δt.sub.2 = 1-10 sec Δt.sub.3 = 1-10 sec (may need to be optimized as indicated with reference to FIG. 8) Δt.sub.4 = 1-10 sec.______________________________________
FIG. 10 graphically illustrates the result obtained with the embodiments described in conjunction with FIG. 8 and FIG. 9, namely it shows no ghost in Image 2 and a sensitivity or relative signal strength similar to that of Image 1.
It should be understood that the invention is not limited to embodiments described above by way of illustration, but that it includes any erasure method using a combination of high voltage and light. The two key steps used within the novel method are: (1) the uniformization of the interface, which occurs when the high voltage is on and the light is on at the same time, and (2) the neutralization of charges accumulated at the interface, which is achieved by reversing the high voltage polarity while leaving the light on; this second step is optional and is required only when decrease in sensitivity is objectionable. Thus, any erasure method comprising one or both of the above steps falls within the scope of the present invention.
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Erasure of an x-ray imaging device is performed by applying high voltage and erasing light simultaneously. The polarity of the high voltage may be reversed during the erasure operation. This produces an erasure that eliminates non-uniformities or ghosts arising from a previous image.
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FIELD OF THE INVENTION
This invention relates to apparatus for use in the humane slaughtering of animals in abattoirs and the like.
BACKGROUND OF THE INVENTION
It is conventional practice to slaughter an animal by first stunning it using a suitable gun which projects a captive bolt at the animal. Conventionally such guns are fired by an explosive cartridge or by compressed gas.
It is frequently necessary, especially in large abattoirs, to deal with a large number of animals in a relatively short space of time. Thus a succession of animals may be conveyed or constrained to walk one at a time past the position at which a stun gun is being used. After each animal is stunned it is conveyed or allowed to slide down a suitable slope away from the stun position.
It is necessary, therefore, that the stun gun be reloaded after each use with a fresh cartridge if it is of the explosive cartridge type. Whereas the compressed gas type of gun does not require such reloading, it is generally accepted that such guns are less effective in stunning an animal and may require more than one attempt.
There is a need, therefore, to provide an apparatus by which stunning using a conventional explosive cartridge-type gun can be speeded up so as to satisfactorily deal with a large number of animals in quick succession.
SUMMARY OF THE INVENTION
Accordingly, the invention provides an automatic reloading machine for stunguns, the machine comprising a carousel having a plurality of spaced holders each to carry a gun, the carousel in one complete revolution passing through a plurality of stations including a first station at which a loaded gun is presented for use and further stations at which a used gun has its bolt reset, the used cartridge is removed and a new cartridge is inserted.
Preferably there are at least two other stations besides the first station where the loaded gun can be obtained. Thus at a second station the bolt of a used gun may be reset to its position ready for firing and the spent cartridge may be removed and at a third station a fresh cartridge is inserted into the breech of the gun.
More stations may be provided. For example there may be up to six stations with each station associated with a particular check or operation. One arrangement of stations could be as follows:
1. used gun loaded onto carousel;
2. used gun has bolt reset and spent cartridge removed;
3. sensor checks that gun chamber is empty;
4. fresh cartridge loaded into gun and gun scanned by sensor to check satisfactorily loaded;
5. the gun may be being cooled, sprayed or checked; and
6. loaded gun available for use.
Thus the operator takes a gun presented at station 6 and uses it. The empty holder at station 6 rotates to station 1 and the operator replaces the used gun back on its holder at station 1. A loaded gun from station 5 reaches station 6 and is available for use and so on.
The gun may be of the known two-part type, i.e. comprising a combined barrel and breech and a separate breech cap. In this arrangement the bolt is held captive in the barrel and the cartridge is housed in the breech. The breech cap, which includes the trigger is then screwed onto the end of the breech when the gun is ready to be used and is unscrewed after use so that the used cartridge can be removed and a fresh one inserted. In the present invention, therefore, the gun holders on the carousel may carry the combined barrel and breech gun parts and the operator retains the breach cap to screw onto the loaded gun he removes from the carousel. He then unscrews the breech cap after use and places the used gun without the breech cap back on the carousel.
Other sensors and indicators may be provided as desired. For example, there may be a "not loaded" indicator sensor between station 6 and station 1. Thus if a loaded gun is not removed at station 6, the mechanism may be controlled to stop the bolt resetting, cartridge removal and cartridge refilling steps as that unused gun continues around on the carousel. A sensor may be provided at station 4 to ensure that the spent cartridge has been satisfactorily removed before that gun is loaded with a fresh cartridge.
Other variants are, of course, possible. For example, station 3 could merely sense that the cartridge has been removed and station 4 could load a fresh cartridge and sense that loading was completed satisfactorily.
The loaded gun may be completely removable from the carousel for use or it may be withdrawn on a suitable arm or bracket.
Additional stations may be provided, as desired, on the machine, e.g. a station for spraying the gun with bacteriocide.
As a gun passes the relevant stations, the resetting of the bolt, the removal of the spent cartridge, the insertion of a fresh cartridge and any other desired operation can all be carried out automatically, e.g. by a series of mechanical arms or other means centrally controlled by a CPU programmed to respond to the various signals provided by the sensors around the machine. The drive mechanism for the carousel may be indexed to advance each holder one position each time a loaded gun is removed or a used gun is returned.
The carousel may pass through a cooling unit on the machine so that the guns, which will heat up rapidly with repeated use, can be cooled as they travel around the stations. For example, in the six station arrangement described above, the cooling unit could embrace stations 4, 5 and 6.
In another particularly preferred embodiment, the holders for the guns are arranged to swivel so that in the bolt resetting and spent cartridge removal station(s) the gun is horizontal. As the carousel takes the gun to the cartridge loading station the holder swivels to position the gun vertically so that the fresh cartridge can be loaded into the vertical gun from above.
A magazine of fresh cartridges can be positioned at the cartridge loading station with an indexing mechanism to load a single cartridge as each gun is brought to that station.
Spent cartridges extracted from the guns can be disposed of in any convenient manner, e.g. dropped via a chute to a storage bin to await removal.
The invention provides significant advantages over conventional methods of using a cartridge-type stun gun. The operator can increase the stun rate by more than 100% compared with a normal manual unload/reload operation and with less operator fatigue. Used cartridges are not left on the floor. The apparatus can conveniently incorporate cooling means so that gun overheating and consequential damage to gun parts can be avoided resulting in greater gun operating life. Also as indicated above, a sterilising unit can conveniently be incorporated in the apparatus so that improved hygiene may be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
Specific embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which;
FIG. 1 is a representation of an apparatus of the invention in use in an abattoir; and
FIG. 2 is a diagrammatic plan view of the apparatus of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, an automatic reloading machine 10 is shown positioned adjacent a conveyor or animal walkway passage 11. An animal 12 to be stunned by operator 13 is shown on the conveyor adjacent the machine.
The machine has a carousel 14 mounted in a housing having a top cover 15 and sidewall 15A and is supported on legs 16.
The carousel has six equi-spaced arms 17 (one of which is shown in FIG. 1 ). Each arm ends in a swivelable bracket 18, thereby forming a holder for gun 19 (two of which are shown in FIG. 1).
The operator is shown removing a loaded gun 19, i.e. a loaded combined gun barrel and breech parts from the machine with one hand. In his other hand he holds a breech cap 20 which he will screw onto the loaded part 19 to form a complete gun ready for use. This loaded gun 19 is presented at an opening in side wall 15A.
Gun 19A has already been used--see its exposed captive bolt 21--and was replaced on the carousel by the operator before he removes the loaded part 19. As can be seen, the holder bracket 18A for the used gun is swivelling from the vertical position at which a loaded gun part is presented to a horizontal position. The housing sidewall contains an extension portion 15B to accommodate the length of the horizontal gun.
Protruding through the roof 15 of the housing is a magazine 22 which contains a number of cartridges for reloading used guns--see below.
The carousel 14 has six gun holders comprising pivotable brackets 18. It rotates within the machine which has six stations 1 to 6 as shown. At station 1 a used gun 19A has been rotated to a horizontal position and is supported on arcuate rail 23. At station 2 a rod 24 contacts bolt 21 of the still horizontal gun and presses it back into its barrel 19B. At the same station a lifting tool 40 is used to lift an extractor 50 and then return it to its original position on the gun 19. Whilst extractor 50 is in its lifted position the spent cartridge 41 can be removed by pulling tool 25.
At station 3 the gun 19 has been rotated back to the vertical position where it is carried on guide rails 26. A sensor, not shown, checks that the breech cover is empty, i.e. the cartridge has been correctly removed, and a cartridge is then loaded into the breech cover (from the magazine 22 shown in FIG. 1). This latter step may be carried out at station 4.
At station 4 a sensor (not shown) checks that the cartridge has been correctly loaded.
At station 5 the loaded gun is in transit to the unloading station 6 where it is presented to the operator.
Between station 6 and station 1 there is an indicator 27 which can inform the operator as to the loaded state of the machine.
From stations 4 to 6 the carousel passes through a cooling unit 28 to cool the used guns. Alternatively the whole machine may be cooled.
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A carousel arrangement for the automatic reloading of captive bolt stunners. The carousel includes stations for cartridge removal, bolt resetting and cartridge insertion. Further stations may incorporate safety checks or cooling devices.
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BACKGROUND OF THE INVENTION
The present invention relates to a heating apparatus for use indoors, especially for use in a fireplace of a house. More particularly, the present invention relates to a heating apparatus which comprises a water container, a fireplace compartment for heating the water disposed within the water container, and a plurality of heat emitting members including a blowing system for circulating hot air from the fireplace through the water and to the heat emitting elements for heating the house while reducing many problems associated with fire danger.
Many types of heating apparatus used indoors are well known in the art. Usually, a fireplace located in the wall of a house is used as a source of heat in cold weather. However, it is very difficult to recover the heat from the fireplace when burning materials such as wood or kerosene. Furthermore, there always exists danger of fire and the mess produced by dust and ash generated from the fireplace. Thus, there are many problems associated with prior art fireplaces or indoor heating apparatus.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved heating apparatus.
Another object of the present invention is to provide a heating apparatus, particularly one which can be positioned in a fireplace of a house.
A further object of the present invention is to provide a heating apparatus comprising a water storage tank, a fireplace chamber for heating the water, a plurality of heat emitting members and a fan for circulating the hot air emitted from the plurality of heat emitting members to the room.
Still another object of the present invention is to provide a heating apparatus which contains a water storage tank disposed on the water container for supplying water to the water container as well as maintaining the humidity of the environment.
A further object of the present invention is to provide a heating apparatus which is structured with a first floor fireplace provided with a burner for burning kerosene and a second floor fireplace for burning firewood so that the heating apparatus can be utilized with both types of fuel, i.e. liquid fuel or firewood or both.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention relates to a heating apparatus which comprises a water container, a fire box for heating the water in the water container, a heating chamber containing a plurality heat emitting members disposed therein, a water storage tank disposed on the water container, and a fan for blowing hot air around the plurality of heat emitting member and circulating the heated air into the room, whereby the heating apparatus produces hot air with a controlled humidity while at the same time reducing fire danger and pollution due to dust smoke and ash.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 is a perspective view of the heating apparatus of the present invention;
FIG. 2 is a cross-sectional view of FIG. 1, taken along line 2--2; and
FIG. 3 is a cross-sectional view of FIG. 1, taken along line 3--3.
DETAILED DESCRIPTION OF THE INVENTION
Referring now in detail to the drawings for the purpose of illustrating the present invention, a heating apparatus 10 as shown in FIG. 1, 2 and 3 comprises a water container 30, adapted to contain water 28, a burner 11 operatively associated with a fire box, disposed in the lower portion of the front side wall of the water container 30, a fireplace door 14 disposed at the middle portion of the front side wall of the water container 30, a water storage tank 22 extending from the top of the water container 30, a plurality of heating chamber 45 disposed in the upper area of the water container 30, and a chimney 41 disposed on the top of the water container 30.
The fire box disposed in the water container 30 includes a first floor 31 and a second floor 33 for burning either firewood or liquid fuel, respectively. The fire box is divided into the first and second floors 31 and 33 by a fireplace shelf 32. Also, the water container 30 includes liquid fuel storage tanks 44 disposed in the lower portion thereof, a plurality of upper and lower heat conduits 37 and 38 while communicate with the fire box for conveying heat from the fire box, and a fan 43 disposed at the upper rear side wall thereof (FIGS. 2 and 3).
The burner 11 mounted to the front side wall through a hinge 12 is provided with an electric wire 13 for igniting and the nozzle 17 is disposed in the second floor 33 of the fire box. The fire box door 14 which has a handle 15 is mounted to the front side wall through hinges 12 and includes a glass 16 having high temperature mechanical properties for viewing the heat conduits 38 (FIG. 1). The fire box shelf 32 contains a plurality of projecting members 49 holding the firewood 34. An air controlling member 48 is mounted to the lowest portion of the front side wall of the water container 30 through hinge 12, and includes a handle 50 and a gauge 51 for controlling the volume of fresh air to the fire boxes 31 and 33 by moving the gauge 51 in the direction indicated by arrow (D) and (E) as shown in FIG. 1. Also, the air controlling member 48 functions as door for cleaning out the ash 36 disposed below the fire boxes 31 and 33.
The lower heat conduits 38 disposed in the middle area of the water container 30 and the plurality of upper heat conduits 37 having a smaller diameter than that of the heat conduits 38 pass through the water container 30 and deliver the heat from the fire boxes 31 and 33 to the chimney 41, heating the water 28 in the water container 30 during the process. The lower heat conduits 38 communicate with the upper heat conduits 37 is a serpentine configuration. The plurality of heat chambers 45 containing a plurality of heat emitting members 46 are heated by the hot water circulating in the water container 30. The fan 43 inserted in a fan housing 21 blows air through chamber 42 in indirect heat exchange with the exhaust gas passing through conduits 38 and 37 into the plurality of heat chambers 45 and heat emitting members 46 for blowing hot air to the outside of the heating apparatus 10 through a plurality of louvers 18. The louvers 18 control the direction of the heat in any desired direction.
The water storage tank 22 comprises a bottle 23 which communicates with the water container 30 and a cap 24 having a handle 25, an extension member 27 (FIG. 3) and a plurality of raised portions for providing a space between the bottle 23 and the cap 24 to permit steam 29 to escape. Thus, the steam 29 from the water storage tank 22 can maintain the humidity in the room. When necessary, the water can be supplied through the top of storage tank 22. Also, since the open water storage tank 22 communicates with the water container 30, the water container 30 is prevented from exploding due to the accumulation of excess temperature or pressure in the container 30.
A controller 19 and a controlling panel 20 are disposed at the front portion in the top wall of the water container 30. The controller 19 controls the temperature in the water container 30 and actuates the fan 43 disposed in the fan housing 21 at a predetermined indoor temperature of the blowing chamber 45. Also, an on/off switch is disposed on the control panel 20 to actuate the burner 11 mounted to the front side wall of the heating apparatus 10.
The liquid fuel storage tanks 44 include feed inlets 40. Usually, the liquid fuel 39 is kerosene. The water container 30 is provided with a water draining member 47 for discharging the water in the container 30.
In the operation, after the water container 30 is filled with water as shown in FIG. 1 and pieces of firewood 34 are disposed on the plurality of the projecting member 49 of the fireplace shelf 32, the on/off switch disposed at the controlling panel 20 is actuated to ignite the nozzles 17 of the burner 11.
The burning firewood 34 heats the water in the water container 30, and the plurality of heat emitting members 46 disposed in the heat chambers 45 are heated by the heated water of the water container 30. At this time, the fan 43 disposed in the fan housing 21 is actuated to blow air through the blowing chamber 42. Accordingly, the hot air around the heat emitting members 46 is blown out in the direction indicated by an arrow (C) as shown in FIG. 3. The hot air is thus transferred to the room environment. The temperature in the indoors can be automatically controlled by the controller 19. By actuating the on/off switch disposed at the controlling panel 20, the burner can be continued or discontinued, as necessary, to burn the firewood 34. Also, the water inlet storage tank 22 is provided with a space so that it can prevent the heating apparatus 10 from exploding and add humidity to the room during the operation of the heating apparatus.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included in the scope of the following claims.
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A heating apparatus comprising a water container, a firebox for heating the water in the water container, a heating chamber containing a plurality heat emitting members disposed therein, a water storage tank disposed on the water container, and a fan for blowing hot air around the plurality of heat emitting member and circulating the heated air into the room whereby the heating apparatus produces hot air with a controlled humidity while at the same time reducing fire danger and pollution due to dust smoke and ash.
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DESCRIPTION
1. Technical Field
The present invention relates to a CAT (computerized axial tomography) scanner using x-rays produced continuously and, more particularly, to a CAT scanner which is not materially affected by pulsating changes in the intensity of the used x-rays.
2. Background Art
The concept of the structure of a CAT scanner is illustrated in FIG. 1, where an x-ray tube 1 and an array 2 of x-ray detectors are rotatably disposed on opposite sides of an object 11 to be examined. The tube 1 emits x-rays in the form of a fan-shaped beam, most of which strikes x-ray detectors 2 2 -2 501 through the object 11. The x-rays are converted into electrical signals by the detectors. The x-rays in the vicinity of both ends of the fan-shaped beam hit reference x-ray detectors A(2 1 ) and B(2 502 ) at both ends of the array 2 without passing through the object 11. The x-rays falling on the reference x-ray detectors are also converted into electrical signals. Capacitors 3 1 -3 502 are connected with the detectors 2 1 -2 502 , respectively, and are charged by the output currents from the detectors. The voltages developed across the capacitors 3 1 -3 502 are applied via first switches 4 1 -4 502 and an amplifier 5 to an analog-to-digital converter 7, where they are converted to digital form. The digital signals delivered from the converter 7 are supplied to a computer 8, where the data is arithmetically processed in accordance with a given procedure to reconstruct an image of the object. The capacitors 3 1 -3 502 are discharged by closing a second switch 6 while the first switches 4 1 -4 502 are closed.
X-rays are produced from the x-ray tube 1 in the form of pulses at certain intervals. Each time one x-ray pulse hits each x-ray detector, the output current is measured. The measurements of the output currents from the detectors are made by controlling the sequence in which the first switches 4 1 -4 502 and the second switch 6 are selectively closed by a control circuit 9 as illustrated by the timing chart of FIG. 4. More specifically, the first switches 4 1`-4 502 are simultaneously closed at instant t 1 before each x-ray detector produces an output current I. Then, they are simultaneously opened at instant t 2 . During this interval the second switch 6 is maintained closed and so the capacitors 3 1 -3 502 are discharged. The output current I rises at instant t 3 when an x-ray pulse falls on the detector, and drops at instant t 4 . The second switch 6 is opened at instant t 5 after a certain period elapses since the output current I drops. During this interval the capacitors 3 1 -3 502 are charged by the output currents I from their respective x-ray detectors. Thereafter, the first switches 4 1 -4 502 are closed for a certain period in a given order to measure the voltages set up across the capacitors 3 1 -3 502 . In particular, if the second switch 6 is opened at instant t 5 , the switch 4 249 , for example, is then closed to measure the voltage developed across the capacitor 3 249 . Then, the switch 4 249 is opened at instant t 6 . Subsequently, the switch 4 250 is closed to measure the voltage produced across the capacitor 3 250 . Subsequently, similar measurements are made of the voltages across the capacitors 3 248 , 3 251 , . . . , 3 1 , 3 502 . This sequence is shown in FIG. 5, where the numbers that the capacitors bear are shown against the numbers that the corresponding x-ray detectors bear.
In this measurement of the output current from each detector on which an x-ray pulse falls, the output current persists for a short time, compared with the period of the measurement. Therefore, in order to obtain a sufficient amount of output current, it is necessary to irradiate the patient with intense x-rays. This has tended to increase the absorbed dose.
In order to reduce the dose absorbed by the patient, continuous x-radiation may be contemplated. Specifically, the output current from each x-ray detector persists for a longer time, enhancing the efficiency of utilization of the detector output current. However, if the measurement sequence shown in FIG. 4 is used, accurate measurement cannot be made, because the period between the recharging of each capacitor and the beginning of measurement of the corresponding detector output current varies among different combinations of detectors and capacitors, and because the capacitors are recharged in different times.
If the scan sequence shown in FIG. 5 is utilized, a considerable period elapses between the instant at which the output currents from the x-ray detectors lying near the center of the detector array is measured and the instant at which the output currents from reference x-ray detectors are measured. During this period the x-ray tube voltage may pulsate, varying the intensity of the emitted x-rays. It is impossible to compensate for the variations in the intensity. Since the measured output currents from the substantially centrally located x-ray detectors are especially important for reconstruction of image, if the changes in the intensity of the x-rays are not compensated for, then the quality of the reconstructed image deteriorates.
DISCLOSURE OF THE INVENTION
It is the object of the present invention to provide a CAT scanner which utilizes detector output currents with high efficiency, is capable of measuring the detector output currents accurately, and reconstructs an image of the object under examination without being materially affected by changes in the intensity of x-rays.
In accordance with the invention, an x-ray tube (1) continuously produces x-rays which are directed to an x-ray detector array (2) via an object (11) to be examined. Capacitors (3 1 -3 502 ) are charged by the output currents from the x-ray detectors (2 1 -2 502 ). First switches (4 1 -4 502 ) and a second switch (6) are controlled by a control circuit (9) in such a way that the voltage produced across each of the capacitors (3 1 -3 502 ) is measured as soon as the previous capacitor is discharged. Then, the capacitor is discharged. Subsequently, it is charged. This process is repeated for every capacitor. The order in which individual processes are initiated is so controlled that the output currents from the x-ray detectors disposed near the center of the detector array are measured at instants very close to the instants at which the output currents from reference x-ray detectors are measured.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a CAT scanner according to the invention;
FIG. 2 is a timing chart for illustrating the operation of the scanner shown in FIG. 1;
FIG. 3 is a diagram for illustrating the sequence of measurements made as illustrated in FIG. 2;
FIG. 4 is a timing chart for illustrating the operation of a conventional CAT scanner; and
FIG. 5 is a diagram for illustrating the sequence of measurements made as illustrated in FIG. 4.
BEST MODE FOR CARRYING OUT THE INVENTION
A CAT (computerized axial tomography) embodying the concept of the invention is now described also by referring to FIG. 1. X-ray tube 1 produces x-rays continuously. Control circuit 9 is used to make measurements in the sequence illustrated in FIG. 2. Clock pulses CL supplied from an external clock circuit 10 to the control circuit 9 are shown in FIG. 2(a). The operation of selected ones (e.g. 4 126 , 4 375 , 4 502 ) of first switches 4 1 -4 502 is illustrated in FIG. 2 (b)-(d). The operation of second switch 6 is illustrated in FIG. 2(e).
The x-ray tube 1 produces x-rays in the form of a fan-shaped beam. Both ends of the fan-shaped beam hit x-ray detectors 2 1 and 2 502 without passing through the object 11 to be examined. The remaining portion of the fan-shaped beam passes through the object 11 and falls on the detectors 2 2 -2 501 . Consequently, the detectors 2 1 -2 502 produce output currents in response to the continuously generated x-rays and serve as reference signals.
These output currents from the detectors are measured in the sequence described below under the control of the control circuit 9 that is clocked with the clock pulses CL supplied from the external clock circuit 10. First, one clock pulse CL is produced at instant t 1 to close the switch 4 126 . Then, the voltage developed across the capacitor 3 126 is measured. Subsequently, the switch 6 is closed at instant t 2 while the switch 4 126 is maintained closed, in order to discharge the capacitor 3 126 which was used for the voltage measurement. The switches 4 126 and 6 are opened at instant t 3 so that the capacitor 3 126 is charged by the output current from the corresponding detector. The capacitor 3 126 is kept charged until the next clock pulse CL is produced and the preparations for the next measurement are complete at instant t 9 .
After the switch 4 126 is opened, the switch 4 375 is closed to measure the voltage produced across the capacitor 3 375 . After the completion of this measurement, the switch 6 is also closed at instant t 4 to discharge the capacitor 3 375 . Thereafter, the switches 4 375 and 6 are opened so that the capacitor 3 375 is charged by the detector output current.
Subsequently, the first switches are controlled in the same manner using the capacitors 3 125 , 3 376 , . . . , 3 250 , 3 251 , 3 501 , and 3 502 in this order. Each time each of these capacitors is employed, the second switch 6 is actuated in the same manner. This sequence of operations is illustrated in FIG. 3, where the numbers that the capacitors bear are shown against the numbers that the x-ray detectors bear.
This series of operations is repeated with the period T 0 of the external clock pulses CL. Accordingly, each of the capacitors 3 1 -3 502 is charged for a certain period of T 0 -T rs , where T rs is the period during which the switch 6 is closed for discharging. Hence, T rs can be called a dead time, and is appropriately set, taking account of the measuring accuracy and the time taken for each capacitor to discharge. In this case, the efficiency of utilization of the input current is defined as (T 0 -T rs )/T 0 . Since the closure time T rs can be made considerably shorter than the period T 0 , it is possible to enhance the efficiency of utilization of the input current. Thus, every capacitor can be charged in the same time. Therefore, the output currents which are produced from the detectors in response to the continuously produced x-rays can be measured correctly. Also, since the utilization efficiency of the input current can be made high, it is possible to lower the intensity of the emitted x-rays. This leads to a reduction in the dose absorbed by the irradiated patient.
Referring again to FIG. 3, two positions which are a certain distance (=the length of the detector array l4) distant from both ends of the array 2 are used as starting points. Selection order paths extending from the starting points to the ends of the array are established. Also, selection order paths extending from the starting points to the center of the array are established. These four paths are selected in a given order. Also, detectors are selected in a certain sequence determined for each path. After the output currents from the x-ray detectors 2 250 and 2 251 disposed close to the center of the array are measured, the output currents from reference x-ray detectors A(2 1 ) and B(2 502 ) are measured. During these successive measurements, changes in the intensity of the emitted x-rays due to variations in the x-ray tube voltage are negligible. Therefore, it is possible to correctly find the reference value of the intensity of the x-rays that cause the detectors 2 250 and 2 251 lying near the center of the array to produce output currents. Consequently, high-quality tomograms can be obtained by making use of the reference value. Furthermore, it is possible to measure the output currents from adjacent x-ray detectors at instants that are rendered as closest to each other as possible.
It should be understood that the measurements of the output currents from x-ray detectors in accordance with the invention are made possible when the period of the external clock pulses is longer than the sum of the time required for the measurements using all the capacitors and the time taken to discharge the capacitors. Therefore, the period of the external clock pulses is restricted by this sum. When it is desired to shorten the period of the external clock pulses, i.e., to increase the rate at which measurements are made, the capacitors are divided into plural groups. A measuring circuit including an amplifier and an analog-to-digital converter is disposed for each group of capacitors. These groups are operated in parallel.
In the above example, two reference x-ray detectors A and B are provided. It is also possible to provide more reference x-ray detectors. In this case, during each single measurement, the output currents from these reference detectors may be measured several times. The output currents from the non-reference detectors may be compensated for, using the output currents from the reference detectors which are measured at close instants.
While the best mode for carrying out the present invention has been described, it should 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 which are delineated by the following claim.
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The present invention provides a CAT (computerized axial tomography) scanner in which x-ray detector output currents are utilized efficiently and can be measured correctly, and which reconstructs an image of an object (11) under scrutiny without being materially affected by variations in the intensity of x-rays. The scanner has an x-ray tube (1) for continuously producing x-rays, which are directed toward an array (2) of x-ray detectors through the object (11). Capacitors (3 1 -3 502 ) are charged by the output currents from the x-ray detectors (2 1 -2 502 ) of the array. A control circuit controls first switches (4 1 -4 502 ) and a second switch (6) in such a way that each capacitor initiates a cyclic process immediately after the previous capacitor is fully discharged. The cyclic process consists of a measurement, a resetting, and a charging. The control circuit also controls the order in which the cyclic operations are initiated, in such a way that the output currents from the x-ray detectors disposed near the center of the array and the output currents from reference x-ray detectors are measured at quite close instants.
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BACKGROUND
[0001] Due to variances inherent in the microelectronics manufacturing process, devices manufactured by the same process and of the same type may have widely varying power consumption. This can lead to issues in burn-in processes and in platform validation tests.
[0002] For example, a typical burn-in process will sort the components to be cycled through burn-in by their power consumption. The devices at each power level are then burnt in separately from devices at other power levels. This requires either more time or more burn-in equipment, making the burn-in process less efficient. In addition, lower power devices have to be burnt in for longer periods of time, as they do not get to the higher temperatures that higher-powered devices reach.
[0003] Similarly, platform validation may suffer from a validation procedure run with a component that is at lower power consumption than what power consumption may be possible. For example, suppose a personal computer (PC) manufacturer receives a sample from a supplier that has a power consumption of 65W during normal operation. The manufacturer then validates their platform at this power consumption. However, during production runs,. The supplier may provide components that run as high as 75W, which is the maximum power specified in the data sheet. This may cause problems for both the manufacturer and the supplier.
[0004] The manufacturer's platform may not perform as well as would be expected, because of the increased power requirement of the component, which also contributes to heat generation, another factor that degrades the performance of microelectronics devices. The manufacturer and supplier relationship may also suffer. The manufacturer, upon receiving the lower power device initially, may assume that the supplier's data sheet specifications for the device are incorrect. When the manufacturer's platforms start to fail due to a power requirement higher than the validation power, the manufacturer may hold the supplier responsible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Embodiments of the invention may be best understood by reading the disclosure with reference to the drawings, wherein:
[0006] [0006]FIG. 1 shows an embodiment of power adjuster circuit.
[0007] [0007]FIG. 2 shows an embodiment of a control system testing a microelectronics device having at least one power adjuster circuit.
[0008] [0008]FIGS. 3 a and 3 b show simulated results of burn-in power prior to enabling a power adjuster and after enabling a power adjuster.
[0009] [0009]FIGS. 4 a and 4 b show simulated results of burn-in junction temperature distribution prior to enabling a power adjuster and after enabling a power adjuster.
[0010] [0010]FIGS. 5 a and 5 b show simulated results of microprocessor power consumption prior to enabling a power adjuster and after enabling a power adjuster.
[0011] [0011]FIG. 6 shows an embodiment of a method to adjust power in an integrated circuit.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0012] [0012]FIG. 1 shows an embodiment of a power adjuster circuit. Due to variations that exist in microelectronics manufacturing processes, some components may have variations in their power consumption. Employing embodiments of the power adjuster circuit, such as that shown in FIG. 1, the power distribution can be more tightly controlled. For example, the power distribution can be tightened to match the data sheet specifications for thermal and electrical validation of platforms using components upon which a power adjuster is employed. Similarly, the component may consume more power using the power adjuster circuit during burn-in. Power consumption raises the operational temperature of the component during burn-in, which in turn increases burn-in acceleration, thus reducing the necessary burn-in time to screen latent defects. Also, adjusting the power consumption allows devices of different non-burn-in power consumption profiles to be burned in simultaneously.
[0013] The embodiment of FIG. 1 shows a power adjuster circuit having several different power consumption levels. A pass gate 10 is enabled with an enable signal 11 . The enable signal may originate from an enable register (not shown) that is programmed on the device for burn-in testing or for validation. When the pass gate 10 is enabled, the power adjuster circuit 12 consumes power proportional to the process technology for a device of width W in saturation mode. The width, W, may be adjusted for each silicon technology and product implementation to provide the level of power necessary to tighten power distributions. For example, a transistor of a width W may consumer an amount of power of X Watts. The designer of the power adjuster circuit may narrow or widen the dimension W to consumer less or more power. Each power adjuster circuit shown in FIG. 1 may be programmed to consume power to allow more flexible adjustment of power consumption.
[0014] For example, the power adjuster circuit itself is enabled by the enable signal 11 . The term power adjuster circuit will be used to refer to one or more power adjusters being enabled by one enable signal. In the embodiment of FIG. 1, the pass gate comprising an NODS transistor 104 and PROS transistor 102 configured in a ‘mirror’ configuration, with their drains tied to Vs. Through the power adjuster 12 , and their sources tied to Vic by the pull up resistor 106 . When the enable signal 11 is turned on, the gate of the NODS transistor goes high and the NODS transistor 104 closes the circuit and conducts. The inverse of the enable signal at the gate of the PROS transistor 102 goes low, closing the circuit and conducting. This would normally cause the gate of the power adjuster transistor 122 to go high, but the gate of the power adjuster transistor 122 is tied to ground by the profuse resistor 124 .
[0015] Whether each individual power adjuster circuit of a pass gate 10 and power adjuster 12 consumes power depends upon the state of the profuse 124 . If the profuse 124 is blown, the resistance will change from approximately 100 ohms to approximately 1 KOH. This results in a balanced voltage divider, resulting in a gate voltage of Vic/2 for the transistor 122 . This causes the transistor to stabilize in saturation mode and consume power proportional to the width W, as discussed above.
[0016] The adjustment of how much power a particular power adjuster circuit consumes depends upon the number of available and the number of blown polyfuses. The embodiment of FIG. 1 shows a power adjuster circuit of 8 power adjusters and their corresponding pass gates. However, a power adjuster circuit could have as many power adjusters and pass gates as the designer desires and as few as one. The number of power adjusters in the circuit will depend upon the technology being used for that component and the normal variation of power consumption for that technology. If the desire were to adjust the power consumption by 4W, blowing the polyfuses would activate the first four elements 1W-4W. This particular embodiment has the possibility of consuming an amount of power up to 8W.
[0017] As discussed above, the power adjuster circuit may be used to tighten the power distribution for components used in platform validations or it may be used to increase the power consumption of components during burn-in test. Embodiments of the invention may have one power adjuster circuit for burn-in and a separate one for validation, or just one power adjuster circuit for either burn-in or validation. For example, a component manufactured during a production run may not be used for validation and would therefore require only the burn-in power adjuster circuit.
[0018] The component undergoing burn-in testing or validation will be referred to as a device under test. FIG. 2 shows a control system in which a component is undergoing test. The control device 14 , such as a workstation or lab equipment, is connected to the device under test 18 , typically by some sort of connector 16 , although the component may be one of an array of devices undergoing test and therefore mounted in a testing platform. The component 18 has an active area 24 , in which the circuitry for that component resides. For example, for a microprocessor, the transistors, memory, etc., for the microprocessor functions would be in the active area 24 .
[0019] In addition, there would be two registers or fuses, one to enable the burn-in power adjustment circuit and one to enable the validation power adjustment circuit used for platform validation. The two enable registers or fuses or other means of originating an enable signal 22 and 26 are shown as being separate components from the active area. However, they may also be included in the active area, such as a flag bit set by the microprocessor upon executing a burn-in or validation instruction. The two power adjustment circuits, burn-in 20 and validation 28 , would then be enabled as needed for the given testing function.
[0020] [0020]FIGS. 3 a and 3 b show simulated results for burn-in power consumption prior to enabling a power adjuster circuit and after enabling the circuit, respectively. As can be seen in FIG. 3 a , the power distribution mean and sigma is 4.18W and 0.64W, respectively. In FIG. 3 b , the actual distribution is much tighter to the ideal, with a mean of 6.76W and standard deviation 0.11W. The tighter the burn-in power distribution, the more controlled the burn-in temperature will be. This will result in a more controlled, cost-effective and higher quality burn-in process.
[0021] [0021]FIGS. 4 a and 4 b show simulated results prior to enabling the circuit and after enabling the circuit for burn-in junction temperature distribution, respectively. Again, the mean temperature after implementation is higher and the standard deviation is smaller. As can be seen the actual temperature distribution tightens up and increases considerably in FIG. 4 b . This would result in an approximate 20-30% reduction in burn-in stress cost and duration. The stress duration and cost reduces as the change in temperature between burn-in stress and use conditions increase. In this example, the mean junction temperature increases 5° C. This reduces the amount of time a component must be burned in.
[0022] Similarly, devices are profiled for power consumption and burn-in temperature depending upon their power characteristics. Typically, devices having the same general profile are burned in together. By controlling the power distribution of the devices, more devices can be ‘programmed’to a particular power level, allowing more devices to be burned in simultaneously, reducing the overall cost of a production run for a particular component.
[0023] Similar to the application of embodiments of the invention to control burn-in power distributions, embodiments of the invention can be used to tighten the power distribution of devices under normal use conditions. This allows platform manufacturers to have ‘good’ samples of the component to validate their platforms.
[0024] Typically, platform manufacturers may receive samples from the component manufacturers that have a range of power consumption profiles, due to variations in microelectronics materials and manufacturing processes. For example, a platform manufacturer may receive a sample of a microprocessor with a power of 70 Watts for its mean, median power, as is shown in FIG. 5 a . The data sheet specification may be 75W. Given a choice between trying to validate and verify the electrical and thermal characteristics of a component with a theoretical value and performing that validation with an actual component that has a lower value, most platform manufacturers will use the actual component.
[0025] However, this may lead to problems. As the components are produced in typical manufacturing runs, the platform manufacturer may receive microprocessors that consume 75W, increasing the temperature and the power needed for the platform.
[0026] This may cause other components to fail, and represents a quality risk for both the platform and the component manufacturer. An example of the power distribution for normal use prior to using and adjuster circuit is shown in FIG. 5 a . Looking at the bar graph at the bottom of the drawing, it can be seen that the power distribution in FIG. 5 b is much tighter than that in FIG. 5 a . Using embodiments of this invention, the simulated power distribution becomes that shown in FIG. 5 b , which alleviates this problem.
[0027] Employing embodiments of the invention, then it is possible to measure the power level of the component and then adjust the power up to the data sheet specification, or to the desired burn-in power. An embodiment of a method to control the power consumption of a component is shown in FIG. 6.
[0028] At 60 , the base power distribution of the device, prior to enabling any power adjustment, is measured. The power difference between the predetermined, desired power level and the base power level is determined at 62 . At 64 , a number of polyfuses are blown to adjust the power by an amount substantially equal to the power difference. The device may then be either burned in at 66 or used for validation at 68 . These last processes are optional and only shown for completeness. In the case of burn-in, the predetermined power level is the desired power level for burn-in cycling. In the case of validation, the predetermined power level is the specified power level on the component data sheet.
[0029] Thus, although there has been described to this point a particular embodiment for a method and apparatus for programmable power adjustment in microelectronics devices, it is not intended that such specific references be considered as limitations upon the scope of this invention except in-so-far as set forth in the following claims.
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A circuit to adjust power is disclosed. The circuit comprises at least one pass gate and a power adjuster electrically coupled to each pass gate such that the power adjuster consumes power when the gate is enabled. The power adjuster consumes power or not depending upon the state of a profuse within the power adjuster.
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This application is a continuation of application Ser. No. 578,180, filed 2-8-84, abandoned
FIELD OF THE INVENTION
This invention is directed to the field of surgery, and more particularly, to a novel infusion system having plural fluid input ports and at least one patient ouput port.
BACKGROUND OF THE INVENTION
Intravenous infusion therapy is prescribed where it is desirable to administer medications and other fluids directly into the circulatory system of a patient. It is estimated that approximately forty percent of U.S. hospital patients presently receive some form of infusion therapy and it is expected that the proportion will grow in the future due to the improved health care that results from such therapy.
For many clinical procedures, it is desirable to intravenously administer several fluids to a patient. Plural independent gravity flow controllers and plural independent electronic pumps have heretofore been employed for this purpose. The plural gravity flow controllers, however, are disadvantageous, among other things, due to the increased possibility of infection occasioned by multiple IV venipuncture; due to the flow inaccuracies occasioned, among other things, by patient movement induced tube occlusion or tubing shape changes; due to the considerable labor and time required from a nurse or other health practioner to manually control the plural gravity flow controllers in accordance with a prescribed course of therapy; due to clutter around the patient; and due to the possibility of out-of-control infusion occasioned by a failure of one or more of the gravity flow controllers. The plural independent pumps are disadvantageous, among other things, due to the clutter around the patient occasioned by the use of plural pumps; due to the increased possibility of infection occasioned by multiple VI venipuncture; due to the comparatively high cost of procuring and maintaining several pumps for each such patient; due to the incapability of the heretofore known pumps to administer more than two infusates in time sequence without additional pumps; due to the incapability of the heretofore known pumps to administer dilutions; due to the considerable time and labor required by the health practitioner to program and to supervise the plural independent pumps; and due to the comparatively high cost incurred in maintaining an inventory of tubes and administration sets that must be replaced periodically to avoid infection for each pump, fluid, and patient, often amounting on an annual basis to about one half the cost of the pumps themselves.
SUMMARY OF THE INVENTION
The novel infusion system of the present invention contemplates means operable to controllably infuse preselected fluids from any one or more of plural fluid input ports either simultaneously or in time sequence through at least one patient output port and into the circulatory system of a patient in a predetermined time sequence. Infusates may be administered from bag or bottle containers or from syringes. A small quantity of fluid may be pumped into the syringe to unstick the syringe plunger. The infusion system of the present invention is operative to identify potentially conflicting infusions and to alert the system operator. The system operator may, among other things, either reschedule conflicting infusions or select an alarm and automatic shutdown prior to the time when conflicting infusions are scheduled to commence. The infusion system of the present invention is operative to administer nonconflicting infusions at the same rate or different rates to provide either mixing of the infusates or dilution of the concentration of one of the infusates.
The infusion system of the present invention is selectively operative in a maintenance mode to controllably administer a fluid from a preselected fluid input port to keep the vein of a patient open at such times when selected fluids are not being infused in accordance with a particular course of infusion therapy.
The infusion system is selectively operable in a priming mode to vent fluid and air from a selected fluid input port to prevent possible air embolism.
The infusion system is selectively operable in a manually initiated override mode to controllably administer any one or more of plural fluids during emergency or other situations.
The infusion system having plural fluid input ports and at least one patient output port of the present invention in preferred embodiment includes a processor. A memory is operatively coupled to the processor. Means coupled to the processor are provided for entering into the memory data representative both of the desired time sequence for and of a desired rate of flow of each of any one of a plurality of fluids to be infused in any order. A plurality of input valves are operatively connected to the processing for accessing the flow of a corresponding one of the fluid inputs. An output valve is operatively connected to the processor for controlling the fluid flow out of the output port. A pumping chamber is operatively connected to the processor and is in fluid communication with each of the input valves and the output valve along a common fluid flow path. Means coupled to the processor and responsive to the data are provided for repetitively actuating the input valves and concurrently expanding the pumping chamber in a time sequence selected to fill the pumping chamber with the corresponding fluid to be infused and for repetitively actuating the output valve and concurrently contracting the pumping chamber at a rate selected to infuse the corresponding fluid through the patient output line at the desired rate. The data entry means includes an operator interactive display and a keyboard. The processor includes a main control processor and a pump control processor slaved to the main control processor. The main control processor is operative to provide operator prompts on the operator interactive display, to provide system status information on the display, and to provide one of plural display templates representative of desired pumping mode and sequence. The pump control processor executes instructions representative of the desired pumping sequence and mode that are down loaded thereto by the main control processor for execution, generates and reports various error and alarm conditions to the main control processor, and generates several alarms including air in line, patient occlusion, and empty bottle. The pumping chamber and the input and output valves are provided in a sterile, disposable, cassette injection-molded out of biologically inert medical-grade plastic. The cassette includes a longitudinally extending channel in fluid communication with the pumping chamber, a pressure chamber, a plurality of fluid input ports, a patient output port, and a vent port. The cassette in preferred embodiment consists of a two part semi-rigid housing and a flexible diaphragm consisting of silicone rubber that is sandwiched between the two parts of the housing. The diaphragm includes a plurality of resilient valve stops that individually project into a corresponding one of the fluid input ports, output port, and vent port, and includes a flexible drum that extends over the pressure chamber and a dome that extends over the pumping chamber. The cassette is oriented preferably at a forty-five degree angle to the vertical with the vent port and pressure chamber above the pumping chamber. Any slight quantity of air in the fluid flow path rises above the pumping chamber and into the pressure chamber thereby preventing the possibility of air passing to the patient. A stepper-motor controlled cam drives a corresponding spring-biased plunger associated with each input fluid port and the output port for controlling the state of actuation of its associated resilient stop. The input and output port plungers are so driven that the patient output port is in a closed state whenever any one of the fluid input ports are in an open state and are so driven that all of the input ports are closed whenever the output is open, to prevent unintended gravity flow infusion. A stepper-motor controlled cam strokes a pumping piston associated with the pumping chamber to extend or contract the pumping chamber for filling or expelling fluid therefrom. A pressure transducer is coupled to the pressure chamber and operatively connected to the pump controller for providing pressure data during each pumping piston stroke representative of air-in-line, bottle head pressure, downstream occlusion, and of variation between actual and intended infusate volume. The system responds to the pressure data to vent fluid and air from the line and to adjust operation in a pressure dependent manner. The system is selectively operable in a controlled mode to allow fluid to flow from any selected fluid input to a selected output under gravity control without actuating the pumping piston whenever desirable.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantageous of the present invention will become apparent as the invention becomes better understood by referring to the following exemplary and non-limiting detailed description of the preferred embodiment, and to the drawings, wherein:
FIG. 1 is a block diagram illustrating the novel infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 2 is a state diagram illustrating the operating states of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 3 illustrates in FIG. 3A an isometric view of a preferred embodiment of a housing for, and illustrates in FIG. 3B a plan view of a preferred embodiment of a control panel for, the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 4A is a plan view illustrating one portion of a cassette of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 4B is a plan view illustrating another portion of the cassette of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 4C is a plan view illustrating a flexible diaphragm of the cassette of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIGS. 4D and 4E are sectional views of the cassette taken along the lines D--D and E--E of FIGS. 4A-4C of the infusion system having plural fluid inport ports and at least one patient output port according to the present invention;
FIG. 5 is a partially exploded perspective view with the cover removed of a valve and pumping actuator of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 6 is a side view of the valve and pumping actuator illustrating rotary position sensors of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 7 is a rolled out view illustrating a position sensor for the valve actuator of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 8 is a rolled out view illustrating a position sensor for the pumping actuator of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 9 is a rolled out view illustrating the operation of the valve and pumping actuator and position sensors of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 10 is a schematic diagram of the system controller of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 11 is a diagram illustrating a data file of the main control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 12 is a diagram illustrating an instruction byte of the main control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 13 illustrates in FIG. 13A a status byte of the pump control processor and in FIG. 13B a communications protocol between the main control processor and the pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 14 illustrates the command bytes of the main control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 15 illustrates the data bytes of the pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 16 is a data flow chart illustrating the operation of the infusion system having plural patient input ports and at least one patient output port according to the present invention;
FIG. 17 is a flow chart illustrating the operation of the main control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 18 is a flow chart illustrating one pumping sequence of the pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 19 is a flow chart illustrating another pumping sequence of the pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 20 is a flow chart illustrating another pumping sequence of the pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 21 is a flow chart illustrating another pumping sequence of the pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention;
FIG. 22 is a flow chart illustrating another pumping sequence of pump control processor of the infusion system having plural fluid input ports and at least one patient output port according to the present invention; and
FIG. 23 is a diagram illustrating an exemplary operating sequence of the infusion system having plural fluid input ports and at least one patient output port according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, generally designated at 10 is a block diagram of the novel infusion system having plural fluid input ports and at least one patient output port according to the present invention. The system 10 includes a disposable cassette generally designated 12 to be described having a fluid channel 14. A plurality of fluid input ports 16, four (designated "A", "B", "C", and "D") being specifically illustrated, are connected to the fluid flow channel 14 through a corresponding one of a plurality of valves 18. Each fluid input port 16 is directly connectable to a selected fluid to be infused, not shown. The cassette 12 includes a pumping chamber generally designated 20 connected to the fluid channel 14, and a pressure chamber generally designated 22 connected to the pumping chamber 20 via a fluid flow channel 24. A patient output port 26 is connected in a fluid flow path to the pressure chamber 22 via a valve 28, and a vent output port 30 is connected to the pressure chamber 22 in a fluid flow path via a valve 32. The patient output port 26 is directly connectable to a patient via a patient output line, not shown. The vent output port 30 is directly connectable, for example, to a collection bag to be described or other fluid sink.
An input and output valve actuator 34 to be described is operatively connected to the plural fluid input valves 18 and to the patient output valve 28. The actuator 34 is operative to select the "open" and the "closed" state of the valves 18, 28, and therewith to control fluid flow from the corresponding fluid input ports 16 into the cassette 12 and to control fluid flow out of the cassette into the patient. The actuator 34 is preferably operative to prevent the input and output valves from being simultaneously in the "open" condition to eliminate the possibility of unintended gravity flow infusion. A separate actuator to be described is preferably connected to the output valve 28 to maintain the patient output port and any selected input port "open".
A vent valve actuator 36 to be described is operatively connected to the vent valve 32. The actuator 36 is operative to select the "open" and the "closed" state of the valve 32, and therewith to control fluid flow from the cassette 12 into the collection bag to remove air from the fluid flow channel during initial setup and during operation of the infusion system.
A cassette-locked-in-place sensor 38 is operative to provide a signal that represents that the cassette is in its intended operating position to prevent fluid leakage and unintended infusion.
A pressure transducer 40 to be described is operatively connected to the pressure chamber 22. The pressure transducer 40 is operative to provide an analog signal representative of the pressure in the pressure chamber 22. An amplifier 42 amplifies the analog signal, and an analog to digital converter (ADC)44 converts the amplified analog signal into digital data. During preselected stages of a pumping sequence to be described, the digital data provides information representative of air in line, of actual infusion volume relative to nominal infusion volume, of patient output line occlusion, and of fluid level remaining to be infused through corresponding fluid input ports 16.
A pumping actuator 46 to be described is operatively connected to the pump chamber 20. The pumping actuator 46 is operative to controllably fill and pump fluid from the pumping chamber 20 into either the patient output port 26 or the vent output port 30 in dependence on the state of actuation of the valves 28 and 32. The pumping actuator 46 is operative to precisely administer an intended amount of fluid in an intended time interval from any one or more of the fluid input ports 16 in any order either in time sequence or in time overlap to dilute the concentration of a selected infusate.
A system controller generally disignated 48 to be described is operatively connected to the input and output valve actuator 34, to the vent valve actuator 36, to the cassette-locked-in-place sensor 38, to the analog to digital converter 44, and to the pumping actuator 46. The system controller 48 is operative to provide control signals to the actuator 34 to "open" and "close" the valves 18 in an intended time sequence, to provide control signals to the actuator 46 to pump the chamber 20 at a rate selected to administer a preselected volume of infusate during a prescribed time interval, and to provide signals to the actuator 36 to eliminate air from the fluid flow path during set-up and during infusion.
An operator interactive display 50 is operatively connected to the system controller 48. The display 50 is operative to display one of plural display templates to be described that individually correspond to the modes of operation of the system controller 48, to display system status information, to display operator prompts to assist the operator in selecting volume, rate, and time of infusion, and to display various error and alarm conditions. The modes includes a flush mode template, a prime mode template, an override mode template, a primary mode template, and a piggyback mode template.
Operator data and function keys 52 to be described are operatively connected to the system controller 48. The data and function keys 52 are operative for selecting the rate, volume, and time of infusion; for selecting the state of operation of the infusion system including the override mode, the priming mode, and the normal-on mode; for controlling the operator interactive display; and for selecting maximum occlusion pressure, minimum infusion rate, and total fluid volume to be administered.
Status light emitting diodes (LED's) 54 are operatively connected to the system controller 48. The LED's 54 are operative to provide a visual indication of the various alarm conditions and of battery status. An audible alarm 56 is operatively connected to the system controller 48 to provide an audible indication of alarm condition. One or more slave interfaces 58 are operatively connected to the system controller 48. Eac slave interface 58 is connectable to an auxiliary pump to be described that may be slaved to the system controller 48 to administer the infusion of an incompatible infusate. A universal asynchronous receiver transmitter interface (UART) 60 is operatively connected to the system controller 48. The UART 60 may be connected to any suitable peripheral device such as a display terminal or a computerized central nurse station.
A rectifier and regulator 62 is connected to a source of AC power 64 such as a conventional hospital outlet via a fusible link 66. A regulator 67 is connected to the rectifier and regulator 62 via a switch 70. The rectifier and regulator 62 and regulator 67 provide power to the infusion system in normal operation. A battery 68 provides power to the infusion system either in the event of a power failure or in the event that it is desirable to move the patient such as between an intensive care unit and an operating room. The battery 68, the rectifier and regulator 62, and regulator 67 are operatively connected to the ADC 44 designated "Voltage Inputs". The system controller 48 is operative in response to a fall in the output of the converter signal from the regulators below a predetermined value to switch to the battery 68, and the controller 48 is operative to activate a corresponding status LED to provide a low battery indication whenever the level of the battery falls below a predetermined level.
Referring now to FIG. 2, generally designated at 72 is state diagram illustrating the principal operating states of the system controller 48 (FIG. 1). In an "off" state 74, the system controller 48 is waiting, its clock is running, and no pumping is occurring. In a "programming" state 76, data is selectably input to specify the time, rate, and volume for fluid to be administered from any one or more of the plural fluid input ports 16 (FIG. 1), and data is selectably input to specify current time, KVO rate, maximum occlusion pressure, and total fluid rate and volume. Data entered is selectably displayable in the "programming" state on the operator interactive display for operator review. In an "override" state 78, the system controller 48 (FIG. 1) is operative in a manual override mode. In the state 78, data is selectably input to specify an emergency infusion rate from a selected one of the plural fluid input ports and to pump the fluid at the specified emergency rate. In a "priming" state 80, data is selectably input to specify an input line as a priming line. The system controller is operative in the "priming" state to allow fluid to flow by gravity from a selected input port through the cassette 12 (FIG. 1) and either into the collection bag to remove air from the cassette or through the output port and into the patient output line prior to venipuncture to remove air from the patient line. In the "priming" state, fluid may also be primed by pumping. In an "auto-on" state 82, the system controller is operative to automatically pump fluid from the input ports at the rates, volumes, and times specified in the "programming" state. The system controller in the "programming" state for a particular one of the plural fluid input ports may also be in the "auto-on" state 82 for the other ones of the plural fluid input ports that may be being infused at a selected rate, volume, and time into the patient in accordance with a desired course of therapy. In a "history" state 84, the system controller is operative to display on the operator interactive display data representative of the total quantity of fluid administered to a patient from the plural fluid input ports at a given time. Data accumulated in the history state 84 can advantageously be employed with a computerized hospital information system. In a "slave pump controller" mode 86, the system controller is operative to control one or more auxiliary pumps. The auxiliary pumps can advantageously be employed to control one or more additional infusions for the administration of an incompatible drug without losing the benefit of integrated infusion control and data accumulation.
Referring now to FIG. 3A, generally designated at 88 is an isometric view illustrating a preferred embodiment of a housing of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. The housing 88 is mounted to a conventional IV pole 92 such that its front panel generally designated 90 to be described is oriented at an angle selected to provide ease of operator access, preferably 45°. A disposable cassette generally designated 94 to be described is slidably mounted in a channel generally designated 96 provided therefor on one side of the housing 88. The cassette 94 is oriented at the same angle of inclination to the vertical to allow both pumping with slight quantities of air in the fluid flow path and the expeditious removal of air from the fluid flow path as appears more fully below. A locking lever 100 having a safety mechanism 102 to be described is pivotally mounted to the housing 88. The lever 100 is operatively connected to a rod to be described that is mounted for reciprocating motion in the housing 88. By simultaneously releasing the locking mechanism 102 and pivoting the lever 100, the rod is operate to removably retain the cassette 94 in the channel 96 on the side of the housing 88 in a manner to be described. The cassette 94 includes four fluid input ports 104, 106, 108, and 110, a patient output port 112, and a vent output port 114. A plurality of fluid containers are positioned a predetermined vertical distance above the housing 88 and directly connected to corresponding of the fluid input ports, two such fluid containers 116, 118 connected to the input ports 104, 106 being specifically illustrated. It will be appreciated that two additional fluid containers, bags, or syringes, not shown, may be directly connected to the ports 108, 110. A plurality of indicating lines 119 are provided on the side of the housing. A patient output line 120 is connected to the output port 112, and a collection bag line 122 is connected between the vent output port 114 and a collection bag removably retained on the back of the housing 88, not shown.
Referring now to FIG. 3B, generally designated at 124 is a plan view of a preferred embodiment of the front panel of the housing of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. The front panel 124 includes an operator interactive display 126 for displaying one of a plurality of display templates to be described. The display 126 preferably is an 80 character LCD display commerically available, for example, from Epson. A plurality of display command keys designated by a dashed box 128 are provided on the front panel 124. The display keys 128 include a clear entry key 130, a last entry key 132, a next entry key 134, and an enter key 136. The clear entry key 130 when pressed clears inadvertently or mistakenly entered data, the last entry key 132 when pressed moves a display cursor to a previous field of a display, the next entry key 134 when pressed moves a display cursor to the next field of a display, and the enter key 136 enters the data entered into the various fields of a display into system memory.
A plurality of rate, volume, and time command keys designated by a dashed box 138 are provided on the front panel 124. The rate, volume, and time command keys 138 include a primary infusion key 140, a piggyback infusion key 142, a flush key 144, and a reset key 146. The primary infusion key 140 when pressed selects the programming state 76 (FIG. 2), and displays a primary infusion template for each fluid input that allows selection of the rate, volume, and time sequence of infusion from any one or more of the plural fluid input ports in any order to implement a prescribed course of therapy that calls for the nonsimultaneous infusion of primary fluids at the same or different rates in a predetermined time sequence. The primary infusion template preferably has the following format.
______________________________________1. PRESS A,B,C, OR D TO PROGRAM LINE: -- CALL BACK Y/N? -- "NEXT"______________________________________
The operator then presses any one of keys 162, 160, 166, 168 to be described. If the operator selects the key 168, designated "A", for example, an "A" appears in the first data field of the primary infusion template. The operator then presses the "next" key 134 and the display cursor moves to the second data field of the infusion primary template. The operator then selects either a key 176 or a key 178 to be described and a "yes" or a "no" appears in the second data field of the template. Call back when selected by pressing the "yes" key 176 specifies that the system operator is to be called back prior to beginning infusion on the selected line. The operator then presses the "next" key 136 again and the system controller is operative to display the following display template.
______________________________________2. LINE A RATE: --ML/HR INFUSE VOL:--ML FOR-HR-MIN CONTAINER: --ML "ENTER"______________________________________
The operator then presses the appropriate data keys 170 to be described and appropriate display command keys 128 to enter a selected rate, volume, duration of fluid to be administered, and container volume for primary line "A". The data fields of the templates are shown herein by either "dashed" underline or by "solid" underline. "Dashed" underline entry is optional. For example, if rate and volume are specified for the above template, the system controller can calculate duration and volume. The operator then presses the "enter" key 136, and the selected data is entered into the corresponding addresses of a data file to be described for that lines. The above process may be repeated for selecting the rate, volume, and time for lines B, C, and D as primary lines.
The piggback infusion key 142, when pressed, selects the "programming" state 76 (FIG. 2) and displays a piggback infusion template that allows selection of the rate, volume, and time sequence from any one or more of the plural fluid input ports in any order to implement a course of therapy that calls for the intermittent infusion of one or more piggyback fluids either at regular repeat intervals or in time overlap to provide a dilution of the concentration of one of the infusates. Piggyback infusions are each preferably less than sixty minutes in duration. The piggyback infusion template preferably has the following format.
______________________________________3. PRESS A,B,C, OR D TO PROGRAM LINE: -- CALL BACK Y/N? --SYRINGE Y/N? --"NEXT"______________________________________
The operator then presses any of keys 162, 164, 166, 168. If the operator selects the key 166, designated "B", for example, a "B" appears in the first data field of the piggyback infusion template. The operator then presses the "next" key 134 and the display cursor moves to the second data field of the piggyback infusion template. The operator then selects either the key 176 or the key 178 and a "yes" or a "no" appears in the second data field of the template. Call back again selects or calls back the operator before infusion on line "B". The operator then presses the "next" key 136 and the display cursor then moves to the third data field of the piggyback infusion template. The operator then selects either the key 176 or the key 178 and a "yes" or a "no" appears in the third data field of the template. Syringe when selected specifies a pumping sequence to unstick the syringe plunger from a preselected fluid input port in a manner to be described. The operator then presses the "next" key 136 again and the system controller is operative to display the following display template.
______________________________________4. LINE B RATE: --ML/HR INFUSE VOL: --ML FOR --MIN Q:-HR X: -- "NEXT"______________________________________
The first data field allows the operator to select rate, the second data field allows the operator to select volume, the third data field allows the operator to select duration in minutes, the fourth data field designated "Q" allows the operator to select repeat interval, and the fifth data field designated "X" allows the operator to select the number of times the same infusion is to be repeated. It is noted that the repeat interval for this template is optional. After entering the data into the data fields and pressing the "next" key, the system controller is then operative to display the following display template.
______________________________________5. B CONTAINER: --ML DILUTE WITH LINE-- DILUENT VOL:--ML RATE:--ML/HR "ENTER"______________________________________
The first data field allows the operator to specify the volume of the fluid container for the "B" line, the second data field allows the operator to select a fluid input line for dilution, the third data field allows the operator to select diluent volume, and the fourth data field allows the operator to select diluent rate. The operator then presses the "enter" key 136 and the data is written into the corresponding address locations of the data file for that line.
The flush key 144 when pressed is operative to allow the selection of one of the plural fluid input ports as a flushing line for buffering one infusate from another and to allow the selection of a variable flush quantity and rate selected to accommodate different lengths of the patient output line 120 (FIG. 3A). The flush display template preferably has the following format.
______________________________________6. FLUSH PATIENT LINE WITH LINE -- RATE --ML/HR VOL: --ML/FLUSH "ENTER"______________________________________
The operator then presses a selected key 162, 164, 166, 168 to specify the flush line for the first data field, and the appropriate keys 170 to specify the rate and volume of flush for the second and third data fields. The operator then presses the "enter" key and the data is entered into the data file. During flushing, the system controller is operative to display the following display template.
______________________________________7. FLUSHING PATIENT LINE WITH LINE -- --ML FLUSHED TILL NOW______________________________________
The reset key 146 when pressed allows the operator to clear a previous rate, time, and volume selection for each of the plural fluid input ports. If an infusion is in process when this key is pressed, the system controller is operative to display on the operator interactive display 128 the following display template to prompt the operator to insure that the key has not accidently been pressed.
______________________________________8. RESET LINE- "ENTER"______________________________________
A plurality of pump command keys designated by a dashed box 148 are provided on the front panel 124. The pump command keys 148 include a start key 150, a stop key 152, an override key 154, and a priming key 156. The start key 150 when pressed is operative to initiate a selected course of infusion therapy. The system controller is operative to display the following template if the start key 150 is pressed for a primary line.
______________________________________9. START LINE -- -- PM-HR-MIN FROM NOW OR AFTER LINE-INFUSION COMPLETE "ENTER"______________________________________
The first and second data fields of the start primary display template allows operator selection of the starting time of the selected line in machine time, the third and fourth data fields allows operator selection of a specified time delay start, and the fifth data field allows operator selection of a start of the designated primary line after termination of infusion on another line. The operator then presses the "enter" key and the selected data is written into the data file address locations for that line.
The system controller is operative to display the following display template if the start key 150 is pressed for a piggyback line.
______________________________________10. START LINE -- -- : --AM-HR-MIN FROM NOW "ENTER"______________________________________
The first data field allows operator selection of the line. The second and the third data fields (hours, minutes) allow operator selection of a specified starting time. The fourth and fifth data fields allow operator selection of specified time delay start before the selected line is started. If no data is entered there, pumping starts at current system time. The operator then presses the "enter" key and the selected data is written into the data field address locations for that line.
The stop key 152 when pressed is operative to terminate the desired course of infusion. The system controller is operative to display the following display template to ensure an intended stop.
______________________________________11. STOP LINE- "ENTER"______________________________________
The data field for the display template allows operator selection of the appropriate line to be stopped, which, when entered, is written to the data file.
The override key 154 when pressed is operative to select the override state 78 (FIG. 2). The override key 154 stops all previously selected infusion parameters and allows the operator to select any one of the fluid input ports at a selected rate for infusion during emergency or other situations. The system controller is operative to display the following template when the key 154 is pressed.
______________________________________12. OVERRIDE LINE --WITH NEW RATE --ML/HR STOPS ALL PROGRAMMED LINES "ENTER"______________________________________
The first data field allows operation selection of the override line, and the second data field allows operator selection of the override rate. The display template advises the operator with a prompt that all previously selected rates, lines, and volumes are no longer in effect.
The prime key 156 when pressed selects the priming state 80 (FIG. 2). The priming key 156 allows the operator to select any one of the fluid input ports to allow fluid to flow from the selected port through the cassette and into either the collection bag or patient output line. The corresponding valves are held open allowing fluid to flow as long as the selected line key is held down. The system controller is operative to display the following display template when the prime key is pressed.
______________________________________13. PRESS & HOLD DOWN KEY TO PRIME LINE- INTO COLLECTION BAG "ENTER"______________________________________
The first data field allows the system operator to select which input port is to be primed into the collection bag. The system controller is operative to continue the priming action from the selected line so long as the corresponding one of the keys 162, 164, 166, and 168 is manually maintained in a closed condition.
If the system operator presses the key 160 after pressing the prime key, the system controller is operative to display the following display template.
______________________________________14. PRESS & HOLD DOWN KEY TO PRIME LINE- INTO PATIENT LINE "ENTER"______________________________________
The first data field of the template allows the operator to select which input port is to be primed into the patient line. The system controller is operative to prime the patient line as long as the corresponding key 162, 164, 166, and 168 is held down.
A plurality of fluid input and output port control keys designated by a dashed box 158 are provided on the front panel 124. The input and output line selection keys 158 include a patient line key 160, a "D" input port selection key 162, a "C" input port selection key 164, a "B" input port selection key 166, and an "A" input port selection key 168. As described above, pressing the prime key 156 followed by pressing the patient line key 160 and with the selected line key held down, selects priming from the selected fluid input port through the cassette and into the patient output line so long as the selected line key is held down. Pressing the priming key followed by pressing any one of the keys 162, 164, 166, and 168 selects priming from the selected fluid input port through the cassette and into the collection bag. As described above, pressing the override key 154 and any one of the keys 162, 164, 166, and 168 selects operation in the override mode for the selected line. The keys 162, 164, 166, 168 are similarly operative when the primary infusion key 140, the piggyback key 142, and the flush key 144 are pressed.
If any one of the keys 162, 164, 166, 168 is pressed alone (that is, when not in combination with any key described above), the system controller is operative to display the status of the corresponding fluid input port using either a primary line or a piggyback line status display template. The primary line status display template preferably has the following format.
______________________________________15. A: --ML/HR INFUSE VOL:--ML PRIMARY INFUSION CONTAINER VOL: --ML______________________________________
The piggyback line status display template preferably has the following format.
______________________________________16. D: --ML/HR INFUSE VOL:--ML Q:--X: PIGGYBACK INFUSION CONTAINER VOL: --ML______________________________________
If the key 160 is pressed alone (that is when not in combination with any key described above), the system controller is operative to display a patient line status template. The patient line status template preferably has the following format.
______________________________________17. OCCLUSION PRES: --PSI MAX RATE: --ML/HR PAT'T LINE PRES: --PSI KVO RATE: --ML/HR______________________________________
The first data field displays occlusion pressure, the second data field displays maximum rate, the third data field displays patient line pressure, and the fourth data field displays keep vein open (KVO) rate.
A plurality of data keys designated by a dashed box 170 are provided on the front panel 124. The data keys 170 include numeric keys "1" through "9" for entering the appropriate infusion parameters including rate, volume, and time for each of the plural fluid input ports, "AM" and "PM" keys to select the corresponding time periods, and "yes" and "no" keys 176, 178 to allow the operator to select among the operator prompts displayed in the various display templates on the operator interactive display 126.
An IV flow sheet key 180 is provided on the front panel 124. The key 180 when pressed is operative to select the history state 84 (FIG. 2). When the key 180 is pressed, the system controller is operative to display up-to-date total infusion volume. The system controller is operative to display the following display template when the key 180 is pressed.
______________________________________18. A:LOG B:LOG C:LOG D:LOG TOTAL FLOW--0 --0 --0 --0 --0 "ENTER"______________________________________
The data fields of the display template are selectably resettable by pressing the reset key 146 in the appropriate data field.
An explain key 182 is provided on the front panel 124. The explain key 182 when pressed in sequence with any of the function keys described above provides an operator display template on the operator interactive display 126 that assists the operator in understanding the function of the corresponding key. Each key preferably should be held down within three seconds after the explain key is pressed to obtain an explanation of the key. Exemplary display templates are omitted for brevity of explication. A mute key 184 is provided on the front panel 124. The system controller is operative when the mute key 184 is pressed to silence the audible alarm.
A plurality of status LED's designated by a dashed box 186 are provided on the front panel 124. The status LED's 186 include an AC power LED 188, a battery LED 190, and an alarm LED 192. The AC power LED 188 provides a visual indication that the infusion system is operative under AC power, the battery LED 190 provides a visual indication that the infusion system is operative under internal battery power, and the alarm LED 186 provides a visual indication of either an alarm condition or an error condition. The system controller is operative to provide an alarm indication to indicate that infusion is complete on a line, to indicate that call back has been requested, to indicate an occlusion situation, to indicate air in line, to indicate a low battery condition, to indicate an out of place cassette, and to indicate that primary infusions are simultaneously scheduled. The system controller is operative to display the following display templates for each of the alarm conditions.
______________________________________19. INFUSION COMPLETE START ANOTHER LINE OR STOP LINE --TO CLEAR ALARM20. CALLBACK REQUESTED, START OR STOP LINES TO CLEAR ALARM21. OCCLUSION IN PATIENT LINE CLEAR OCCLUSION & START LINES22. AIR IN LINE OR UPSTREAM OCCLUSION PURGE AIR & START LINES23. LOW BATTERY VOLTAGE CONDITION PLUG AC CORD INTO RECEPTICLE24. CASSETTE LOCK LEVER NOT IN PLACE RETURN TO LOCK POSITION & START LINES25. PRIMARY INFUSIONS OCCUR SIMULTANEOUSLY MUST RE-PROGRAM START TIME______________________________________
The system controller is operative to provide an error indication to indicate pump failure and to indicate an out-of-range entry or invalid key. The corresponding error display templates preferably have the following formats.
______________________________________26. PUMP FAILURE SERVICE REQUIRED27. VALUE OUT OF RANGE OR INVALID KEY: PRESS RESET KEY FOR HOME OMNIGRAM: READ MANUAL______________________________________
The system controller is operative to display the following "home" display template indicating system status whenever it does not display any of the above described display templates.
______________________________________28. A:OFF B:OFF C:OFF D:OFF TOTAL 12:00AM 0 0 0 0 0 ML/HR______________________________________
The states for each of the lines will be either "OFF", "PGM", "ON", "OVR", or "KVO". "OFF" indicates that the corresponding line is in an inactive state; "PGM" indicates that the corresponding line has been programmed to pump at a selected rate, volume, and time; "ON" indicates that the corresponding line is pumping; "OVR" indicates that the corresponding line is in the override state; and "KVO" indicates that the corresponding line is in a keep vein open mode.
Additional display templates to set current time, to select maximum occlusion pressure, to select maximum infusion rate, and to select a keep-vein-open mode and rate are displayed by pressing the "*" key 174 followed by a corresponding data key "1", "2", "3", and "4". These display templates preferably have the following format.
______________________________________29. CURRENT TIME --: -- -- "ENTER"30. MAXIMUM OCCLUSION PRESSURE: -- PSI "ENTER"31. MAXIMUM TOTAL INFUSION RATE: -- ML/HR "ENTER"32. KVO RATE: -- ML/HR "ENTER"______________________________________
The operator then presses the "enter" key and the selected data is enterred into the corresponding address locations provided therefor in the data file for each display template.
Referring now to FIG. 4, generally illustrated at 194 in FIG. 4A is a first housing portion, generally designated at 196 in FIG. 4B is a second housing portion, and generally designated at 198 in FIG. 4C is a flexible diaphragm of a disposable cassette of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. As shown in FIG. 4A, the housing portion 194 includes an injection molded clear plastic member 200 that meets appropriate U.S. Pharmacopia standards. The member 200 includes an integral upstanding peripheral flange 202 and a longitudinally extending fluid flow channel 204. A plurality of longitudinally spaced fluid input apertures generally designated 206 and a pumping chamber generally designated 208 are integrally formed with the member 200 in communication with the fluid flow path channel 204. A channel 210 is integrally formed with the plastic material 200 between the pumping chamber 208 and a pressure chamber generally designated 212. The chamber 212 is integrally formed with the plastic material 200. A patient output aperture generally designated 214 and a vent output aperture generally designated 216 are integrally formed with the plastic material 200 and are in fluid communication with the pressure chamber 212. A disc 218 having a central aperture 220 is provided over the pressure chamber 212 that cooperates with the walls defining the pressure chamber to prevent the collapse of the diaphragm 198 (FIG. 4C) into the chamber 212. As best seen in FIG. 4D, the cassette housing portion 194 includes an annulus 222 defining an input fluid port integrally formed surrounding a corresponding one of the fluid apertures 206, 214, 216 (FIG. 4A). Diametrically opposed locking flanges 224 are integrally formed on the ends of each annulus 222. The plastic member 200 includes longitudinally extending shoulders 225 that abut longitudinally extending guides provided therefor on the side of the housing 88 (FIG. 2A) that prevents the movement of the cassette 94 (FIG. 3A) in a direction transverse to its plane.
Referring now to FIG. 4B, the housing portion 196 includes a clear plastic member 226 that mates in fluid tight sealing engagement with the housing portion 194 (FIG. 4A). The member 226 includes a longitudinally extending diaphragm receiving recess 228. A plurality of longitudinally spaced input valve plunger receiving apertures generally designated 230 are provided through the plastic member 226. An output valve plunger receiving aperture 232 is provided in the plastic member 226 and a vent valve plunger receiving aperture 234 is provided in the plastic member 226. An upstanding annular flange 236 integrally formed with the plastic member 226 is provided surrounding each of the input valve plunger receiving apertures 230, the vent valve plunger receiving aperture 234, and the output valve plunger receiving aperture 232. A semicircular channel portion generally designated 238 integrally formed in the plastic member 226 is provided surrounding each of the annular flanges 236 that are in communication with the channel 228. The plastic member 226 of the housing portion 196 includes a pumping piston receiving aperture generally designated 240 and a pressure transducer receiving aperture generally designated 242. An annular flange 244 integrally formed in the plastic member 226 in communication with the channel 228 is provided surrounding the aperture 240, and an annular flange 246 integrally formed in the plastic member 226 is provided surrounding the aperture 242. Semicircular channel portions generally designated 249 are also provided around the annular flanges 244, 246. A recess 247 is provided intermediate the flanges 244, 246 forming a continuation of recess 228. The ends of the flanges 236, 244, 246 are flush with the generally planar surface of the plastic member 226.
Referring now to FIG. 4C, the diaphragm 198 is preferably an injection molded length of silicone rubber that meets the appropriate U.S. Pharmacopia standards. The diaphragm 198 includes a longitudinally extending reinforced seal portion 248 having a transverse width greater than the transverse width of the longitudinally extending fluid channel 204 (FIG. 4A) that is received in the recess 228 (FIG. 4B). A plurality of longitudinally spaced input fluid valve pads generally designated 250 are provided on the longitudinally extending reinforced seal portion 248. Individual ones of the valve pads 250 are aligned with corresponding ones of the apertures 206 (FIG. 4A) and apertures 230 (FIG. 4B). The valve pads 250 include an annular recess 252 that is individually aligned with a corresponding one of the annular flanges 236 (FIG. 2B) and an integral upstanding cyclindrical projection 254 that are individually aligned with corresponding ones of the apertures 206 (FIG. 4A) and apertures 238 (FIG. 4B).
A convex dome 256 surrounded by an annular recess generally designated 258 is provided on the diaphragm 198. The recess 258 is aligned with the annular flange 244 (FIG. 4B) and the dome 256 is aligned with the aperture 240 (FIG. 4B) and the pumping chamber 208 (FIG. 4A). A thin circular portion 260 is provided on the diaphragm 198. The portion 260 is aligned with the flange 246 (FIG. 4B) and the pressure chamber 218 (FIG. 4A). A vent valve pad generally designated 262 is provided on the diaphragm 198 between the members 256, 260 in alignment with the apertures 216 (FIG. 4A), 234 (FIG. 4B), and a patient output valve pad generally designated 263 is provided adjacent the cylindrical depression 258 in alignment with the apertures 214 (FIG. 4A), 232 (FIG. 4B). Each of the pads 262, 263 include an integral upstanding cylindrical projection surrounded by an annular recess like those described above for the pads 250. The cylindrical projections of the valve pads 250, 262, 263 have dimensions larger from the dimensions of the corresponding aligned apertures of the member 194 to provide a seal thereagainst to prevent fluid flow. The thickness of the portions 248, 256 (FIG. 4C) is selected to provide a stiffness sufficient to prevent their unintended collapse into the portions 204, 208 (FIG. 4A) during operation.
In the assembled condition of the disposable cassette as best seen in FIGS. 4D and 4E, the diaphragm 198 is sandwiched between the housing portion 194 and the housing portion 196. The longitudinally extending seal portion 248 of the diaphragm 198 is received in the diaphragm receiving recess 228, the solid cylindrical projections 254 of the valve pads 250, 262, 263 extend into corresponding ones of the apertures 230, 232, 234, the dome portion 256 is received over the mouth of the pumping chamber 208, and the cylindrical depression 254 is received over the disc 218 and pressure chamber 212. Any suitable means such as ultrasonic welding may be employed to secure the two housing portions together in fluid tight sealing engagement. The cassette is oriented in use preferably at 45° to the vertical as described above in connection with the description of FIG. 3A. As will readily be appreciated, any air in the fluid flow channel 204 (FIG. 4A) rises upwardly therealong through the pumping chamber 208 (FIG. 4A) and fluid path 210 into the pressure chamber 212 (FIG. 4A). As appears below, the system controller is operative to detect any air in the pressure chamber and to appropriately open the vent output valve to vent the air and to alarm should the condition persist. Since the air rises upwardly into the pressure chamber, the pumping chamber in normal operation is substantially free of air. When the pumping chamber is controllably exhausted, only the intended infusate is administered into the patient output port thereby preventing the possibility of admitting air into the patient.
Individual ones of a plurality of valve plungers to be described are received in corresponding ones of the apertures 230, 232, 234 (FIG. 4B) that are reciprocally moveable to push corresponding upstanding cylindrical projections 254 (FIG. 4D) into sealing contact with the apertures 206, 214, 216 to control the state of actuation of the corresponding fluid valves. The cyclindrical projections with their associated plunger withdrawn flex out of contact with the corresponding apertures to allow fluid flow into and out of the pumping chamber 208. A pumping piston to be described is received in the pumping piston receiving aperture 240 (FIG. 4B). The piston is reciprocally moveable to controllably push the dome 256 (FIG. 4C) into the pumping chamber 208 as can best be seen in FIG. 4E. The fluid that accumulates therein during each pumping sequence to be described is thereby pumped through the patient output port and into the circulatory system of a patient. The rate of reciprocating motion of the pumping piston, its travel distance into the chamber 208, and the time interval between pumping strokes is selected to controllably administer intended volumes of infusant in intended time intervals.
Referring now to FIG. 5, generally designated at 264 is a partially exploded perspective view with the cover removed of a valve and pumping actuator of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. The assembly 264 includes a plurality of fluid input port valve plungers 266 each coaxially aligned with a corresponding one of the fluid input apertures 230 (FIG. 4D), an output valve port plunger 268 coaxially aligned with the output port aperture 232 (FIG. 4B), a vent valve port plunger 270 coaxially aligned with the collection bag aperture 234 (FIG. 4B), and a pumping chamber piston 272 coaxially aligned with the pumping chamber aperture 240 (FIG. 4E).
Each of the fluid input valve plungers 266 are slideably mounted in and fastened to a corresponding one of a plurality of rocker arms 274 that are individually pivotally mounted to a U-shaped support illustrated dashed at 276. A roller 278 is fastened to an end of each of the rocker arms 274. A cam 280 moving one lobe drives any selected one of the rollers 278 to withdraw the corresponding fluid input plunger 266 out of the corresponding ones of the fluid input port apertures. A compression spring 282 is slideably mounted on and fastened to corresponding ones of the plurality of fluid valve input plungers 266. The springs 282 act against one wall of the U-shaped support 276 urging the plungers 266 into corresponding ones of the fluid input ports designated "A", "B", "C", "D" of a cassette schematically illustrated at 283 to maintain the corresponding valves in a normally closed condition.
The output valve plunger 268 is slideably mounted in and fastened to one end a rocker arm 284 that is pivotally mounted to the support 276. A roller 286 is fastened to an end of the rocker arm 284 remote from the end in which the plunger 268 is mounted. A cam 288, having two lobes 180° apart, coaxial with the cam 280, drives the roller 286 to withdraw the output valve plunger 268 out of the output valve aperture. A solenoid 290 having a displacable ram 292 is fastened to the support 276 with its ram 292 in contact with the end of the rocker arm 284 remote from the plunger 268. The ram 292 is selectably actuable to withdraw the output valve plunger 268 out of the output valve aperture. A spring 294 is slideably mounted on and fastened to the plunger 268. The spring 294 acts against the one wall of the U-shaped support 276 urging the plunger 268 into the output port aperture for biasing the output valve in a normally closed condition. The cam 280 and the coaxial cam 288 are mounted for rotation with the shaft of a stepper motor 296. The system controller controllably rotates the stepper motor 296 to selectively actuate the input and output valves to implement a desired pumping sequence as appears more fully below. The lobes on the cams 280, 288 are so arranged as to prevent any input port and the output port from being simultaneously in an open condition for any rotary position of the stepper motor 296 to prevent unintended gravity flow infusion. Whenever it is desired to simultaneously open any input port and the output port such as during priming, the system controller rotates the stepper motor 296 to the position that opens the selected input port and actuates the solenoid 290 to open the output port.
The vent plunger 270 is slideably mounted in and fastened to a rocker arm 298 that is pivotally mounted to the U-shaped support 276. A solenoid 300 having a displaceable ram 302 is fastened to the support with its ram 302 in contact with the rocker arm 298. The ram 302 is selectably actuatable to withdraw the vent output valve plunger 270 out of the collection bag output aperture to open the vent valve. A spring 304 is slideably mounted on and fastened to the vent plunger 270. The spring 304 acts against one wall of the U-shaped support 276 urging the plunger 270 into the collection bag port to maintain the vent valve in a normally closed condition.
A pressure head 306 fastened to a pressure transducer 308 via a longitudinally adjustable mechanical linkage 310 is coaxially aligned with the pressure chamber. The pressure head 306 includes an internal coaxial rod, not shown, positioned over the aperture 220 (FIG. 4A) that is displaced in a direction along its length in response to pressure variations in the pressure chamber 212 (FIG. 4A). The pressure transducer 308 converts the linear movement into an analog signal proportional to pressure in the pressure chamber.
A roller 312 is fastened to the end of the pumping piston 276 that is remote from the end that enters the pumping chamber 208 (FIG. 4A). A cam 314 having a spiral shaped bearing surface mounted for rotation with the shaft of a stepper motor 316 selectively drives the roller 312 for controllably displacing the pumping piston 272 for reciprocating motion into and out of the pumping chamber 208 (FIG. 4A). The support 276 is mounted in the housing for sliding motion by a mechanical linkage generally designated 303 connected between the lever 100 and the support 276. The linkage 303 includes a rod 305 pivotally mounted on one end to the lever 100 and connected on its other end to a member 307. A spring biased rod generally designated 309 is connected on one end to the support 276 and on its other end to a cam, not shown, interiorly of the member 307. A microswitch 311 is provided for sensing the axial position of the lever 100. Lifting the lever 100 axially out of the safety mechanism 102 and rotating it either clockwise or counterclockwise displaces the member 307 thereby urging the rod 309 toward and away from the support 276 for moving the support 276 and therewith the plungers and pistons into and out of the associated apertures provided therefor on the cassette. The switch 311 senses the axial position of the lever 100 to provide an indication of whether or not the cassette is locked in place. Extending alignment rods 313 are provided that cooperate with associated apertures provided therefor on the cassette, not shown, to help align the cassette in its intended operating position.
Referring now to FIG. 6, generally designated at 332 is a side view of the valve and pumping actuator illustrating position sensors of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. The position sensors are operative to provide signal indications of the intended rotary position of the stepper motors. An annular sleeve 324 is mounted for rotation with the cams 280, 288 and stepper motor 296. As best seen in rolled out view in FIG. 7, the annular sleeve 324 has an open portion generally designated 328 and a closed portion generally designated 330. As shown in FIGS. 6 and 7, a dashed line 334 designates a first light path and a dashed line 336 designated a second light path through which the sleeve 324 rotates. The light paths 334, 336 may be provided by any suitable light emitting and light receiving devices such as infrared emitters and cooperative infrared detectors. As the sleeve 324 rotates it alternately transmits and occludes the light paths 334, 336 providing signal indications to be described of the rotary position of the stepper motor 296 to insure its intended rotary position.
An annular sleeve 338 is mounted for rotation with the cam 314 and the stepper motor 316. As best seen in rolled out view in FIG. 8, the sleeve 338 has an open portion generally designated 342 and a closed portion generally designated 344. As shown in FIGS. 6 and 7, a dashed line 346 designates a first light path and a dashed line 348 designates a second light path through which the sleeve 338 rotates. As the sleeve 338 rotates it alternately occludes and transmits the light paths 346, 348 providing signal indications to be described of the rotary position of the stepper motor 316 to insure its intended rotary position.
Referring now to FIG. 9, generally designated at 350 is a rolled out diagram illustrating the operation of the valve and pumping actuator and position sensors of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. A line 352 illustrates the state of actuation of the "A" fluid input port (FIG. 1), a line 354 illustrates the state of actuation of the "B" fluid input port (FIG. 1), a line 356 illustrates the state of actuation of the "C" fluid input port (FIG. 1), and a line 358 illustrates the state of actuation of the "D" fluid input port (FIG. 1). The states of actuation 352, 354, 356, 358 depend on the rotary position of the stepper motor 296 (FIG. 5) that drives the cam 280 (FIG. 5) into contact with selected ones of the rollers 278 (FIG. 5) thereby displacing the corresponding plungers 266 (FIG. 5) out of contact with the corresponding cyclindrical valve projection 254 (FIG. 4D). A line 360 illustrates the state of actuation of the patient output port 26 (FIG. 1). The state of actuation of the output port depends on the rotary position of the stepper motor 296 (FIG. 5) that drives the cam 288 into contact with the roller 286 (FIG. 5) thereby displacing the plunger 268 out of contact with the cyclindrical valve projection 254 (FIG. 4D). When any one of the fluid input port valves are in an open condition as illustrated by the "peaked" portions of the lines 352, 354, 356, 358, fluid from the corresponding fluid container flows into the disposable cassette 94 (FIG. 3A) along the longitudinally extending fluid flow channel 204 (FIG. 4A) and into the pumping chamber 208 (FIG. 4A) so long as the corresponding fluid input port is maintained in an open condition and the pumping piston is withdrawn out of the pumping chamber. After filling the pumping chamber with the selected fluid from any one of the plural fluid input ports, the system controller is operative to rotate the cam 288 (FIG. 5) to either of the two "peaked" positions of the line 360 (FIG. 9) to open the output valve 26 (FIG. 1) to allow fluid to flow through the patient line 120 (FIG. 3A). The system controller during a pumping sequence is operative to take several pressure measurements and to alarm when appropriate in a manner to be described. Fluid admitted into the cassette from the "B" and from the "C" fluid input ports are administered from the left hand "peaked" position of the line 360, and fluid admitted into the cassette from either the "A" and from the "D" fluid input ports are administered from the right hand "peaked" position of the line 360. In priming mode for the patient output line, the system controller is operative to rotate the stepper motor 296 to the position that opens the selected one of the fluid input ports, and to activate the solenoid 290 (FIG. 5) to open the patient output valve to allow priming fluid to flow from the selected fluid input port through the cassette and into the patient output line to prevent the possibility of admitting air into the patient. The sleeve 326 (FIG. 6) alternately occludes and transmits light along the light paths 334, 336 (FIG. 6) producing signal indications designated 362 and 364 of the rotary position of the stepper motor 296 (FIG. 6) to within one step accuracy of the left and right hand "peaked" positions of the line 360. As appears below, the signals 362 and 364 are used by the system controller to insure the proper orientation of the cam 280 (FIG. 5). A line 366 illustrates a pumping sequence of the pumping plunger 272 (FIG. 5), beginning at a vertical line designated 367 and ending at a vertical line designated 369. The sleeve 338 (FIG. 6) alternately occludes and transmits light along the light paths 346, 348 (FIG. 6) producing signal indications 368, 370 of the position of the stepper motor 316 (FIG. 6) to within one step accuracy of the start and end positions of the piston 242 (FIG. 5) during a pumping sequence. As appears below, the signals 368, 370 are used by the system controller to insure proper orientation of the cam 314 (FIG. 5).
Referring now to FIG. 10, generally designated at 372 is a schematic diagram illustrating a preferred embodiment of the system controller of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. The system controller 372 includes a first processor 374 and a second processor 376 slaved to the first processor 374. A bit serial asynchronous communication link 378 interconnects the processors 374, 376. The processor 374 controls operator input and output (I/O), and down loads instructions over the serial communication link 378 into dual ping-pong buffers 379 for execution by the processor 376. The processor 376 controls in accordance with the instructions the state of actuation of the fluid input port valves and of the patient and vent output valves, controls the reciprocating motion of the pumping chamber piston at a rate and for a duration specified by the instructions, reads information representative of the pressure in the pressure chamber and writes information to the processor 374 representative of alarm situations and pressure data. As appears more fully below, the processor 374 is operative in response to the measured pressure data to adjust the reciprocating motion of the pumping piston to adapt desired to actual fluid flow rates.
The system I/O and pump control processor 374 includes a data bus 380 and an address bus 382 connected thereto in the usual manner. A plurality of function and data keys 384 described above in connection with the description of FIG. 3B are connected by an interface 386 to the data bus 380. An operator interactive display 388 described above in connection with the description of FIG. 3B and an associated electrically erasable E2 ROM 390 are connected to the data bus 380 by an interface 392. A real time clock 394, a plurality of infusion LED's 396, and a nurse call signal generator 398 are connected by an interface 400 to the data bus 380. A data RAM 402 is connected to the bus 380 and to the address bus 382. A program PROM 404 is connected to the address bus 382 and to the data bus 380. An auxiliary pump processor 406 is connected to the data bus 380 via an interface 408 and a second auxiliary pump 410 is connected to the data bus 380 via an interface 412. A RS 232 interface 414 is connected to the data bus 380 via an interface 416. A peripheral device 418 such as a display terminal or a central control computer interface is connected to the RS 232 interface 414. The interfaces 386, 392, 400, 408, 412, and 416 format and buffer data between the data bus and the associated devices in a manner well known to those skilled in the art. An address decoder 420 is connected to the address bus and to the interfaces 382, 392, 400, 408, 412, and 416 via a plurality of control lines 422. The address decoder 420 decodes the addresses appearing on the address bus and activates the corresponding control line to enable the addessed peripheral device for data reads and writes via the data bus 380. Battery and alarm LED's 424 described above in connection with the description of FIG. 3B are operatively connected to the processor 374.
Referring now to FIG. 11, generally designated at 426 is a data file of the RAM 402 (FIG. 10). The data file 426 includes a block of selectively addressable RAM memory generally designated 428 for fluid port "A", a block of RAM memory generally designated 430 for fluid input port "B", a block of RAM memory generally designated 432 for fluid input port "C", and a block of RAM memory generally designated 434 for fluid input port "D". Each block of RAM memory 426, 428, 430, and 432 at corresponding preselected address locations thereof specify an operator selected data structure for the corresponding fluid input port. The system I/O and pump control processor 374 selectively addresses the RAM 402 (FIG. 10) over the address bus 382, and writes into the selectively addressed RAM location the data selected by the operator over the data bus 380 as described above in connection with the description of FIG. 3B. The data structure for each line includes data representative of whether it is a primary or piggyback line. The data structure for primary lines includes data representative of infusion rate, infusion volume, infusion duration, and fluid container volume. The data structure for piggyback lines includes data representative of dilute line, dilute volume, and dilute rate for piggyback dilutions, and data representative of duration (Q) and repeat interval (X) for time sequential piggyback lines. The data structure for each line includes data representative of "prime" mode, "override" mode, and "normal-on" mode, and data representative of start time either after a selected delay or after infusion on a designated line. The data structure for each line includes data representative of syringe, and the preselected line for unsticking the syringe plunger. The data structure for each line includes data representative of flush and the selected flush line, flush volume, and flush rate. The data structure for each line further includes data representative of "call back", and data representive of measured pressure including patient pressure, compliance pressure, and bottlehead pressure to be described.
The data file 426 includes a block of selectably addressable RAM memory generally designated 436. The data structure of the block of RAM 436 for each line specifies data representative of the current history of the infusions already pumped on that line.
The data file 426 includes a block of selectively addressable RAM memory generally designated 438 that specify global parameters for all the lines. The data structure of the block of RAM 438 specifies data representative of current time, maximum occlusion pressure, maximum infusion rate and volume, and KVO rate.
Returning now to FIG. 10, the PROM 404 includes in preselected address locations thereof the code specifying the program for the system I/O and pump control processor 374. The PROM 404 also includes at preselected address locations thereof the display templates that prompt the system operator for both selecting a desired course of infusion and for selecting and controlling system operation described above in connection with the description of FIG. 3B.
A data bus 426 is operatively connected to the pump control processor 376. RAM and PROM for the pump processor, not shown, are associated therewith in the usual manner. The pump control processor PROM contains the code specifying any one of possible pumping sequences to be described. Conventional latched drives 428 operatively connected to the data bus 426 are connected to a valve stepper motor 430. Conventional latched drives 432 operatively connected to the data bus 426 are connected to a pump stepper motor 434. An analog to digital converter (ADC) 436 operatively connected to the bus 426 is connected to a pressure transducer 438 via a conventional analog signal conditioning module 440. Voltage inputs designated "V 1 -V 6 " are connected to the ADC 436 to monitor system power level as described above in connection with the description of FIG. 1. A plurality of control lines 442 are operatively connected to the pump control processor 376 for selecting the latched drives 428, for selecting the latched drives 432, and for selecting the analog to digital converter 436. A patient line solenoid 439 is connected to the latched drives 428, and a vent valve solenoid 441 is connected to the latched drives 432. Position sensors generally designated 444 operatively connected to the pump control processor 376 and the latched drives 428, 432 provide signal indications representative of the rotary position of the valve stepper motor 430 and of the rotary position of the pump stepper motor 434 described above in connection with the description of FIGS. 6-9. The pump control processor is operative in the usual manner to enable selected ones of the devices 428, 432, and 436 by the corresponding control line, and to read and write at the appropriate times during a pumping sequence data thereto over the data bus 426.
Referring now to FIG. 12, generally designated at 448 is a table illustrating an instruction byte produced by the system I/O and pump control processor 374 (FIG. 10) for controlling the pump control processor 376 (FIG. 10). The instruction byte includes eight bits designated 0 through 7. The one bit designated "ALL" of the bit field specifies that all data read by the pump processor is to be read by to the system I/O and pump control processor. The two bit designated "V 1 -V 6 " of the bit field specifies that the battery and regulator voltage data measured by the analog to digital converter is to be read by the system I/O and pump control processor. The three bit of the bit field designated "D 0 -D 7 and C 4 " specifies either that the maximum occlusion pressure are to be written by the system I/O and pump processor to the pump processor or that the pressure and error data bytes "D 0 -D 7 " to be described are to be read by the system I/O and pump control processor from the pump processor. The four bit designated "norm and other" of the bit field specifies whether the system is to operate in the normal mode or not. The five bit designated "read/write" of the bit field specifies whether data is to be read by the pump control processor or whether data is to be written by the pump control processor. The six bit designated "X/Y" of the bit field specifies which of the ping-pong buffers is to be receive the next command. The seven bit designated "abort" of the bit field specifies whether an abort by the pump control processor. As shown by the table 448, the first instruction specifies whether the X or the Y buffer is to be aborted. The second instruction reads a status byte designated "S" to be described. The third instruction reads D 0 through D 7 . The fourth instruction reads V 0 to V 6 . The fifth instruction reads S, D 0 through D 7 , V 0 through V 6 , and C 0 through C 4 to be described. The sixth instruction writes C 0 through C 3 and reads D 0 through D 2 . The seventh instruction writes C 4 , and reads D 3 . The eighth instruction instructs the pump processor to take a reference pressure measurement designated 0 PSI to be described.
Referring now to FIG. 13A, generally designated at 450 is a status byte "S". The status byte is produced by the pump control processor and includes data representative of the state of the X, Y ping-pong buffers and of the mode of operation of the pump control processor. The status byte 450 includes eight bit positions 0 through 7, with the zero and one bits of the bit field specifying control mode, the second bit of the bit field specifying Y error buffer, the third and fourth bits of the bit field specifying the state of Y buffer, the fifth bit of the bit field specifying an X buffer error, and the sixth and seventh bits of the bit field specifying the state of the X buffer. As shown in the state table, a "0, 1" specifies that the corresponding X or Y buffer is waiting to execute; a "1, 0" specifies that the corresponding instruction is being executed; a "1, 1" specifies that the corresponding buffer is ready for a new instruction; and a "0, 0" specifies an initialization state for the corresponding buffer. As shown in the control table designated "CNTL", a "0, 0" specifies continuing the current control function and a "1, 1" specifies stopping the current funtion.
Referring now to FIG. 13B, generally designated at 452 is a timing diagram illustrating the communications protocol of the processors 374, 376 (FIG. 10). The boxes above the dashed line 454 illustrate the instructions written from the system I/O and pump control processor 374 to the pump control processor 376, and the boxes below the dashed line 454 illustrate the data read from the pump control processor by the system I/O and pump control processor 374. For the exemplary communications protocol, the pump control processor 374 sends over the transmission link 378 an instruction designated "I RD STAT" to read the status byte as illustrated at 456. The pump control processor 376 receives the instruction as illustrated at 458, and sends the status byte having the control bits "0, 0" back to the system I/O and pump conrol processor 374 as illustrated at 460. The system I/O and pump control processor receives the status byte as illustrated at 462, and sends it back to the pump control processor instructing it to continue as illustrated at 464. The process continues until the system I/O and pump control processor 374 instructs the pump control processor 376 to stop as illustrated by the box 466 having the control bits "1, 1". The pump control processor continues until it receives the instruction to stop as illustrated at 468 and sends it back to the system I/O and pump controller processor as illustrated by the box 470. The system I/O and pump control processor then sends an acknowledge instruction designated "ACK" to he pump control processor as illustrated by the box 472, which is received by the pump control processor 376 as illustrated by the box 474. It will be appreciated that a similar communications protocol is implemented for each of the instructions and commands written by the system I/O and pump control processor to the pump control processor.
Referring now to FIG. 14, generally designated at 476 is the C 0 command byte; generally designated at 478 is the C 1 command byte, generally designated at 480 is the C 2 command byte, generally designated at 482 is the C 3 command byte, and generally designated at 484 is the C 4 command byte. The 0 through 6 bits of the bit field of the C 0 byte 476 specify a number of microstrokes per pump stroke, and the seventh bit of the bit field specifies priming. The 0 through 12 bits of the bit field of the C 1 , C 2 bytes 478, 480 specify the time per pump stroke, preferably in tenths of a second, and the 13 through 15 bits of the bit field of the C 1 byte 478 designated "T 0 -T 2 " specify which of the pump processor PROM pumping sequences to be described is to be executed. The 0 through 4 bits of the bit field of the C 3 byte 482 specify the number of pump strokes, the fifth and sixth bits of the bit field of the C 3 byte 482 specify from which fluid input port fluid is to be administered, and the seventh bit of the bit field specifies either that the vent output valve or the patient line output valve are to be actuated. The C 4 byte 484 specifies the maximum occlusion pressure selected by the system operator.
Referring now to FIG. 15, generally designated at 488 is the D 0 data byte. The D 0 data byte represents the bottle height pressure designated "P2" read by the pump processor and written in pump processor RAM during the pumping sequence. The bottle height pressure is the ADC reading of the pressure chamber when only an input valve is open normalized by the 0 PSI value. The D 1 data byte is generally designated at 490. The D 1 data byte represents the air-in-line compliance pressure designated "P4" read by the pump processor and written in pump processor RAM during the pumping sequence. The air-in-line compliance pressure as appears below is the difference of the ADC reading of the pressure chamber when the piston is successively driven partially in the pumping chamber and all valves are closed. The D 2 byte is generally designated at 492. The D 2 data byte represents volume correction designated "N1" and "N2" to be described read by the pump processor and written in pump processor RAM during the pumping sequence. The volume correction data as appears below depends on the pressure data and is employed to adapt actual to desired pumping rates. The D 3 data byte is generally designated at 494. The D 3 data byte represents the zero PSI pressure designated "P1" read by the pump processor and written in pump processor RAM during the pumping sequence. The 0 PSI pressure is the ADC reading of the pressure chamber when any input is just opened and the output valve is closed and the pumping piston is withdrawn prior to water hammer effects. The D 4 data byte is generally designated at 496. The D 4 data byte represents matching pressure designated "P3" to be described read by the pump processor and written in pump processor RAM during the pumping sequence. The D 5 data byte is generally designated at 498. The D 5 data byte represents the patient pressure designated "P5" read by the pump processor and written in pump processor RAM during the pumping sequence. The D 6 and D 7 bytes generally designated 500 and 502 have data therein representative of various error and alarm conditions that the pump controller monitors. The D 6 and D 7 data bytes are written during a pumping sequence in pump processor RAM. The D 6 and D 7 data bytes include data representing whether the stepper motors out are of proper rotary position, patient pressure greater than maximum occlusion pressure, air-in-line pressure less than minimum compliance pressure, empty bottle pressure, and cassette locking lever out of place.
Referring now to FIG. 16, generally designated at 504 is a data flow chart illustrating the operation of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. As illustrated by the blocks 505, 506, the system I/O and pump control processor is operative to determine that a valid key, or combination of keys, has been entered. If a valid key or key combination has been entered, the processor is operative as shown by a block 508 to select the corresponding display template stored in PROM as shown by blocks 508, 510 and to display the selected template on the operator interactive display as shown by a block 512. If the display template corresponds to either the pump command display templates or the rate/vol./time display templates, the processor is operative to address for each data field the corresponding data locations in the data file 514 as illustrated by a block 516, and to write the operator selected data into the corresponding address locations of the data file for any selected one or more of the plural fluid input ports A, B, C, and D. As illustrated by a block 517, the system I/O and pump control processor is operative to write the data into the RAM data file to provide RAM redundancy for preventing errors. The 0 through 6 bits of the bit field of the C 0 command (FIG. 14) and the 13 through 15 bits of the bit field of the C 1 command (FIG. 14) are specified by the data file.
As shown by a block 518 the system I/O and pump control processor is operative to read the data file address locations and the time as shown by a block 521 to determine if it should institute a pumping sequence on an active line. As shown in FIG. 17, which generally designates at 523 a flow chart of the active line sequencer, the processor is operative to determine whether the data file specifies operation in the priming mode as shown by a block 520. If the data file contains data representative of priming for any one of the input valves, the processor is operative to produce instructions to stop all other pump functions as shown by the block 522, to produce instructions to prime the designated line as shown by a block 524, to produce instructions to inactivate all the fluid lines as shown by a block 526, and to return processing to the block 519. If the data file specifies operation in the override mode as shown by a block 528, the processor is operative to produce instructions to stop all nonoverride functions as shown by a block 530, to produce instructions to pump the line designated at the specified rate as shown by a block 532, to inactive all fluid lines as shown by a block 534, and to return processing to the block 519. If the data file specifies operation in the flush mode as shown by a block 536, the processor is operative to produce instructions to suspend all nonflush functions as shown by a block 538, to produce instructions to flush the designated line as shown by a line 540, to reset the flush line as shown by a block 542, and to return processing to the block 519 as shown by a block 544. If the data file specifies operation in the auto-on mode as shown by a block 546, the processor is operative to determine whether the time for infusion is the present time or whether more delay is needed as shown by a block 458. If no more time is needed, the processor is operative to determine whether the data file designates the line as a primary line as shown by a block 550. If the line is a primary line, the processor is operative to determine whether the data file specifies call back as shown by a block 452. If call back is specified, the processor is operative to sound an alarm and to pump in the KVO mode as shown by a block 554. If no call back is specified in the data file, the processor is operative to produce instructions to pump the specified line as shown by a block 556, and returns processing to the block 519 as shown by a block 558. If the line is a piggyback line, the processor is operative as shown by a block 551 to determine whether call back is specified in the data file. If call back is specified in the data file, the processor operative to sound an alarm and to pump in the KVO mode as shown by a block 553. If no call back is specified, the processor is operative to determine if the data file specifies a syringe as shown by a block 555. If a syringe is specified, the processor is operative to produce instructions to stop all other functions and to unstick the syringe plunger as shown by a block 557. The processor is then operative to produce instructions to pump from the syringe at the selected rate as shown by a block 559, and to return processing to the block 519 as shown by a block 561. If syringe is not specified, the processor is operative to produce instructions to pump the designated line at the specified rate as shown by the block 556, and returns processing to the block 519 as shown by the block 558. The active line sequencer specifies the 7 bit of the bit field of the C 0 command and the 5, 6, and 7 bits of the bit field of the C 3 command.
Returning now to FIG. 16, if any of the lines are active as described above in connection with the description of FIG. 17, the processor is operative to calculate the number of strokes for the pumping plunger to effectuate the desired duration and rate of infusion. The processor is preferably operative to calculate the number of strokes per second according to the following relation: ##EQU1## where Rate I is the specified infusion rate in milliliters per hour and VOL eff is the effective infused volume calculated as described below. The tenths of second per stroke data is written in the 0 through 12 bits of the bit field of the C 1 and C 2 commands bytes.
The processor is operative to buffer the instructions and commands described above in connection with the description of FIGS. 12 and 14 in a command queue as shown by a block 566, which are written to the pump control processor as shown by a block 568 into a specified one of the X or Y buffers as illustrated by the blocks 570, 572. As illustrated by a block 575, the pump control processor is operative to fetch the instructions from the appropriate buffer, and executes the specified pump control sequence as shown by a block 576 to controllably rotate the valve stepper motor to close and open the designated fluid input ports as illustrated by a block 578 and to controllably rotate the piston stepper motor to repetitively actuate the pumping piston as illustrated by a block 580. The pump control processor is operative during the pumping sequence to store in RAM the LED sensor signals from the valve stepper motor sleeve as illustrated by a block 582, and to store in RAM the LED sensor signals from the pump stepper motor sleeve as illustrated by a block 584. The pump processor is operative to read the analog to digital converter as shown by a block 586, to activate the vent output valve solenoid and the patient output line solenoid as shown by a block 589, and to write into pump control processor RAM the D 0 -D 7 data as shown by a block 591 during the pumping sequence.
Referring now to FIG. 18, generally designated at 592 is a flow chart illustrating an exemplary pumping sequence of the pump control processor. The sequence 592 is preferably employed to controllably pump infusate at comparatively low operator selected rates of flow. As shown by a block 594, the processor is operative to open the specified one of the fluid input port valves, to withdraw the pumping piston, and to write the A/D reading into the D 3 RAM data location to measure 0 PSI. The processor is then operative to wait a predetermined time to allow fluid to flow from the selected input port into the pumping chamber as shown by a block 596.
The processor is then operative to write the A/D reading normalized by the 0 PSI reading into the D 0 data RAM location to measure the bottlehead pressure of the corresponding fluid container designated P2. The processor is then operative to close the valves as shown by a block 600 and to drive the pumping piston a selected distance, preferably four steps of the stepper motor, into the pumping chamber, and delays as shown by a block 602. The processor is then operative to write the A/D reading of the pressure transducer in RAM to take the matching pressure designated P3 as shown by a block 604. The processor is then operative to drive the pumping piston into the pumping chamber a further selected distance, preferably eight additional steps of the stepper motor, and delays as shown by a block 606. The processor is then operative to write the A/D reading of the pressure transducer designated P4 into RAM as shown by a block 608.
As shown by a block 610, the processor is then operative to compare the difference of the readings to determine whether air is in the line, to write the difference in the readings into the D 1 RAM data location, and to either proceed or alarm in dependence on whether the change in pressure is below a minimum preselected reference compliance pressure. As shown by a block 612, if air is in the line, the processor is operative to abort the pumping sequence. The processor is then operative to vent air from the line using a pumping sequence to be described, to alarm as shown by a block 614 if air is in the line preferably for three consecutive measurements, and processing for each measurement is returned to the block 594. As shown by a block 616, if no air is in the line, the processor is operative to withdraw the pumping piston out of the pumping chamber a preselected distance selected according to the measured pressures preferably calculated according to the relation 8(P4-P5L)/(P4-P3) steps of the stepper motor. The pressure P5L is the P5 pressure from the last stroke to be described. If P5L has yet to be measured in the pumping sequence, the processor assumes a specified value for the pressure P5L preferably equal to 0 PSI+5. The processor is then operative to open the patient output line valve as shown by a block 618 and to write the A/D reading of the pressure transducer into RAM to measure the patient pressure designated P5 as shown by a block 620.
As shown by a block 622, the processor is then operative to determine whether the pressure P5 is less than the pressure P3. As shown by a block 624, if the pressure P5 is greater than the pressure P3, the processor is operative to successively drive the pumping piston step by step fully into the pumping chamber and to write the corresponding A/D reading into RAM. The processor is operative to compare the pressure reading for each step to the maximum occlusion value specified in the C4 command byte 484 (FIG. 14) to determine whether the patient line is occluded. if the line is occluded, the processor is operative to alarm if the pressure doesn't drop within a predetermined time interval, for example, 30 seconds. The processor is then operative to close the input and output valves as shown by a block 626. As shown by a block 628, the processor is then operative to withdraw the pumping piston and write A/D reading into RAM. The processor then steps the pumping piston into the pumping chamber incrementally by steps of the stepper motor and writes the A/D reading into RAM. The processor is operative to repeat this process until the measured pressure equals the matching pressure P 3 and stores that rotary position of the pumping piston stepper motor designated N 2 in RAM where the measured pressure equals the pressure P 3 . As shown by a block 630, the processor is then operative to drive the pumping piston fully into the pumping chamber and to open the patient output line valve as shown by a block 632.
If the pressure P5 is less than the pressure P3, the processor is operative to successively drive the pumping piston almost fully into the pumping chamber, and to write the corresponding A/D reading into RAM. The processor is operative to compare the pressure reading for each step to the maximum occlusion value specified in the C4 command byte 484 (FIG. 14) to determine whether the patient line is occluded. If the line is occluded, the processor is operative to alarm if the pressure doesn't drop within a predetermined time interval, for example, 30 seconds. The processor is then operative to close the input and output valve as shown by a block 636. As shown by a block 638, the processor is then operative to incrementally drive the pumping piston step by step into the pumping chamber and to write the corresponding A/D reading in RAM. The processor continues the process until the measured is equal to the matching pressure P3 and stores the rotary position of the stepper motor at which the measured pressure equals the pressure P3 designated N 1 in RAM. As shown by a block 640, the processor is then operative to return the piston to the position of the stepper motor in the block 634, and to open the patient output line as shown by a block 642. The processor is then operative to drive the piston fully into the pumping chamber to pump the corresponding fluid into the patient output line as shown by a block 644.
Referring now to FIG. 19, generally designated at 646 is a flow chart illustrating another exemplary pumping sequence of the pump control processor. The sequence 646 is preferably employed to pump infusate at comparatively higher operator selected rates of flow. The flow chart 646 is similar to the flow chart 592 (FIG. 18) except that the processor is operative to skip some of the patient pressure monitoring steps of the flow chart of FIG. 18 to allow for faster pumping rates. As described above, the particular pumping sequence is specified by the state of the 13, 14, and 15 bits of the bit field of the C 1 command byte, and that the processor can be instructed to do several cycles of the pumping sequence illustrated in FIG. 19 followed by a sequence of the pumping sequence illustrated in FIG. 18 repetitively. As shown by block 648, the processor is operative to open a selected fluid input port valve, to withdraw the pumping piston, and to write the A/D reading of the pressure transducer into the D 3 data byte. The processor is then operative to wait to allow the pumping chamber to fill with fluid from the selected fluid input port as shown by a block 650. The processor is then operative to write the A/D reading of the pressure transducer into the D 0 data byte as shown by a block 652. As shown by a block 654, the processor is then operative to close the fluid input and output port valves and then to drive the pumping piston a preselected distance into the pumping chamber, preferably twelve steps, and to delay as shown by a block 656. The processor is then operative to write the A/D reading of the pressure transducer into RAM to measure the compliance pressure for determining air in line as shown by a block 658.
As shown by a block 660, the processor is then operative to determine whether the compliance pressure minus the 0 PSI pressure is greater than the preselected maximum compliance pressure to determine whether there is air in line. As shown by a block 662, if there is air in line, the processor is operative to abort the current pumping sequence, to vent air from the line, to alarm as shown by a block 646 if air remains in the line preferably for three consecutive measurements, and processing for each measurement is returned to the block 648. As shown by a block 666, if no air is in the line, the processor is operative to open the patient output line. The processor is then operative to drive the pumping piston into the pumping chamber and write the A/D reading into RAM. If the pressure is greater than the maximum occlusion pressure, the processor is operative to alarm as shown by a block 668.
Referring now to FIG. 20, generally designated at 670 is another pumping sequence of the pump control processor. The sequence 670 is preferably employed to vent air from the fluid flow path as described above in connection with the description of FIGS. 18 and 19. As shown by a block 672, the processor is operative to open the preselected fluid input port to be used for venting. The processor is then operative to withdraw the pumping piston out of the pumping chamber to allow the fluid to fill into the pumping chamber as shown by a block 674. The processor is then operative to open the vent valve as shown by a block 676 and to drive the pumping piston into the pumping chamber to clear air from the fluid path as shown by a block 678. As shown by a block 680, the processor is then operative to close the vent valve. It will be appreciated that air may also be removed from the fluid flow path by the pressure of the gravity head without driving the piston into the pumping chamber.
Referring now to FIG. 21, generally designated at 684 is a flow chart illustrating another exemplary pumping sequence of the pump control processor. The sequence 684 is preferably employed to unstick the plunger of a syringe fluid input. As shown by a block 686, the processor is operative to open the valve of the fluid port preselected as the unsticking fluid port and to withdraw the pumping piston to allow the unsticking fluid to flow into the pumping chamber as shown by a block 688. The processor is then operative to close the unsticking fluid valve as shown by a block 690 and to open the fluid input having the syringe as shown by a block 692. The processor is then operative to drive the pumping piston into the pumping chamber as shown by a block 694. The expelled fluid is thereby pumped through the cassette and into the syringe to unstick the plunger. The processor is then operative to close the syringe valve as shown by a block 696 and then to open the unsticking fluid valve as shown by a block 698. The processor is then operative to withdraw the pumping piston out of the pumping chamber to allow the unsticking fluid to flow into the pumping chamber as shown by a block 700. The processor is then operative to close the unsticking fluid valve as shown by a block 702 and to open the syringe valve as shown by a block 704. The processor is then operative to drive the pumping piston into the pumping chamber to once again displace fluid therefrom into the syringe to unstick its plunger as shown by a block 706. The processor is then operative to do two cycles from the syringe to remove the fluid pumped thereinto to unstick the syringe plunger as shown by a block 708.
Referring now to FIG. 22, generally shown at 710 is another exemplary pumping sequence of the pump control processor. The sequence 710 is preferably employed to abort a pumping sequence as described above in a connection with the description of FIGS. 18 and 19. As shown by a block 712, the processor is operative to close the fluid input and patient line output port valves and to open the vent valve as shown by a block 714. The processor then operative to drive the piston into the pumping chamber as shown by a block 716. The processor is then operative to close the vent valve as shown by a block 718 and to open the patient output line valve as shown by a block 720.
Returning now to FIG. 16, as shown by a block 722, the system I/O and pump control processor is then operative to read the status and data information compiled by the pump processor during the pumping sequences described above and write it back to the data file. The processor is then operative to strip off the D 0 through D 5 data bytes as shown by a block 724. As shown by a block 726, the processor is operative to adapt the desired volume to the actual volume preferably according to the following relations,
VOL.sub.eff =V.sub.0 -A(100-N2). 1
VOL.sub.eff =V.sub.0 -A(88-N1). 2
where V 0 is the volume of the pumping chamber, A is the volume displaced from the pumping chamber per step, 100 represents the total number of steps of the stepper motor of a pumping sequence, 88 refers the rotary position where the pumping piston is driven almost completely into the pumping chamber as described above in connection with block 634 (FIG. 18), and N1 and N2 are determined as described above in connection with blocks 628, 638 (FIG. 18).
As shown by a block 728, the processor is operative if the status information written into the data file indicates any of the several error and alarm conditions to select the corresponding display template as shown by a block 730, to display it on the operator display as shown by a block 732, and to generate the appropriate audible and visual alarms as shown by a block 734. As shown by block 736, if any of the explain, history, mute or status keys are depressed, the processor is operative to select the appropriate display template as shown by a block 730 and to display it on the operator interactive display as shown by the block 732.
Referring now to FIG. 23, generally designated at 626 is a diagram illustrating an exemplary operating sequence of the infusion system having plural fluid input ports and at least one patient output port according to the present invention. The sequencing diagram 626 illustrates pumping from the "B" fluid input port, and then pumping from the "D" fluid input port, utilizing the pumping sequence of FIG. 19, although it will be appreciated that any other valve order and pumping sequence is a variation of that specifically illustrated in FIG. 23. A line 738 illustrates the state of actuation of the "A" input valve, a line 740 illustrates the state of actuation of the "B" fluid input port, a line 742 illustrates the state of actuation of the "C" fluid input valve, and a line 744 illustrates the state of actuation of the "D" fluid input port value. A line 746 illustrates the state of actuation of the output valve designated "O" and a line 748 illustrates the rotary position of the pump plunger stepper motor during the exemplary sequence. A line 750 illustrates the reading of the pressure transducer.
The pump processor is operative to rotate the valve stepper motor through the open position 752 of the "A" port and stops at the open position 754 of the "B" port. With the "B" valve in the open condition as the pumping piston is withdrawn as illustrated at 756, fluid flows from the "B" fluid input port into the cassette and through the longitudinally extending fluid passageway thereof into the pumping chamber. The processor is operative to take the A/D reading of the pressure transducer to measure the 0 PSI value as shown at 758. After sufficient delay to allow filling of the pumping chamber, the processor is operative to take a reading from the analog to digital converter as shown at 760 to measure the bottle height pressure. The processor is then operative to close the "B" fluid input port as shown at 762. The pump processor is then operative to controllably push the pumping piston into the pumping chamber by rotating the pump stepper motor preferably 12 steps as illustrated at 764. The pump processor is then operative to take the reading of the analog to digital converter with the pumping plunger partially into the pumping chamber to measure the corresponding pressure as illustrated at 766. The change in pressure 768 is indicative of air-in-line and is stored in the appropriate data byte. Assuming for the exemplary sequence that no air is in line, the processor is then operative to rotate the valve stepper motor to open the output valve as illustrated at 770 and to rotate the pump stepper motor to controllably displace the piston into the pumping chamber as illustrated at 772. The processor is operative to take the A/D reading during pumping and to alarm if there is an occlusion situation, not illustrated. The processor is then operative to rotate the valve stepper motor to close the output valve as shown at 774, and to repeat the cycle until the desired volume of fluid is administered into the patient through the "B" input port. At the appropriate time, the processor is then operative to rotate the valve stepper motor through the open position of the "C" port as shown at 776 to the open position 778 of the "D" port to commence a pumping sequence through the "D" fluid input port. The above cycle is then repeated for the "D" port but is omitted for brevity of explication.
It will be appreciated that many modifications of the presently disclosed invention will be apparent to those skilled in the art without departing from the scope of the appended claims.
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An infusion system for administering multiple infusates at individually programmable rates, volumes, and sequences in any order from any one or more of plural fluid input ports through a patient output port and into the circulatory system of a patient. Infusates may be either continuously or time sequentially administered, and infusates may be either intermittently administered at selectively regular intervals or in time overlap to administer a dilution. Various error conditions are automatically detected and alarms generated in the event of conflicts between infusates, to identify times of no infusions, and to identify system malfunctions. The system is selectively operable, among others, in a priming mode, a maintenance mode, a normal-on mode, and a manual override mode. The system is operative to adapt actual to desired flow rates in normal operartion. All fluids flow through a unitary disposable cassette without making any other system contact. Air bubbles in the fluid line are automatically detected and disposed of. Fluid pressures are monitored and system operation adjusted as a function of such pressures. Infusates may be administered from syringes as well as from standard bag or bottle containers. Infusate from a selected input port may be controllably pumped into a syringe for unsticking the syringe plunger. The system is selectively operable to adjust total fluid volume and rate to below preselected values for patients whose total fluid intake must be restricted. The system is operable to maintain an accurate record of total infusion history.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional Application of co-pending U.S. patent application Ser. No. 13/257,489 filed Sep. 19, 2011, which application is a National Stage application of PCT Application PCT/EP2010/053500 entitled Alumina, Luminophores and Mixed Compounds, and Associated Preparation Processes, which was filed on Mar. 18, 2010, published in the French language and claims priority to French application FR0901317 filed on Mar. 20, 2009 which applications are hereby incorporated by reference in their entireties.
FIELD
[0002] The present invention lies in the field of aluminates and luminophores and the preparation thereof, and also fluorescent coatings, in particular for the manufacture of display screens, lighting, projectors, in particular plasma screens or field-emission screens, backlight lamps for liquid-crystal screens, light-emitting diodes, plasma-excitation light bulbs and trichromatic bulbs.
BACKGROUND
[0003] A fluorescent tube is made in its conventional form from a hermetically sealed glass tube filled with low-pressure mercury vapour and with a rare gas such as neon, argon or krypton. Electrodes inside the tube, when in operation, emit electrons that excite the gas mixture inside the tube and lead to emissions in the ultraviolet range (for example at about 300 nm).
[0004] This ultraviolet light is converted into visible light by means of a fluorescent coating deposited on the inside of the tube.
[0005] In the case of a “monolayer” coating, the coating comprises luminophore particles, known, for example, under the names BAM, CAT or YOx, and also alumina particles that act as reflectors.
[0006] Generally, 80% of this layer is composed of luminophore particles and 20% of particles of alumina or of alumina of gamma type.
[0007] The luminophore particles generally have a size d 50 of between 4 μm and 10 μm.
[0008] Now, it is known that the cost of luminophores is predominant in the overall cost of the coating.
[0009] In a thesis defended on 17 Oct. 2008 in the University of Paris 6 by Serge Itjoko, a study was undertaken firstly to model the behaviour of fluorescent layers and secondly to identify optimization routes in terms of yield and cost. This thesis is cited by reference in the present patent application as a prior art.
[0010] It emerges in particular from this study of a mixed layer or monolayer that an optimization may be achieved by “selecting luminophore radii that are much smaller than those of the existing luminophores, i.e. radii of between 0.4 μm and 1.2 μm, and radii of alumina grains that are much larger than those of the existing alumina grains, i.e. radii of greater than 0.6 μm”.
[0011] This study gives merely a theoretical result, given that it is a theoretical modelling study, but gives no indication how such luminophores and alumina particles may be obtained. In particular, on page 173 of this thesis, it is stated that “commercial luminophores have a radius ranging between 3 μm and 6 μm” and that luminophores with a smaller size than this have not yet been developed.
SUMMARY
[0012] One object of the present invention is to overcome the drawbacks of the known coatings and to propose formulations and preparation processes for achieving the theoretical objectives of the abovementioned study.
[0013] In particular, one subject of the invention is an alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape.
[0014] A subject of the invention is also the use of an alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape as a matrix for a luminophore.
[0015] According to another aspect, the subject is the use of an alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape as a matrix for a luminophore in a coating for fluorescent lamps.
[0016] A subject of the invention is also a process for preparing an alumina of alpha type composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape, comprising the following operations:
gamma alumina obtained via the alum route is mixed with a sintering agent and alpha alumina seeds, the mixture is calcined in an oven at a temperature of between 1150° C. and 1400° C., especially 1350° C., for a time of between 1 hour and 6 hours, especially 2 hours, the calcined mixture is ground, the ground mixture is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0021] The invention may comprise one or more of the following characteristics, taken alone or in combination:
[0022] According to one aspect of the invention, the sintering agent is NH 4 F.
[0023] According to another aspect of the invention, the mixture is composed, in weight proportions, of 85% to 95% gamma alumina obtained via the alum route, of 2.5% to 13% of alpha alumina and of 0.4% to 1.8% of NH 4 F.
[0024] According to yet another aspect of the invention, the mixture is composed, in weight proportions, of about 93.5% gamma alumina obtained via the alum route, of about 5.5% alpha alumina and of about 1% NH 4 F.
[0025] According to another aspect of the invention, the calcined mixture is ground in a ball mill with alumina milling beads at least twenty times greater in amount than the calcined mixture, for 16 hours.
[0026] According to one particular aspect, the alumina milling beads have a diameter of about a centimetre, especially between 3 cm and 5 cm.
[0027] A subject of the invention is also an aluminate luminophore in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 μm and 1.5 μm.
[0028] According to another aspect of the invention, the luminophore is an aluminate in the form of a composition corresponding to the formula:
[0000] a(M 1 O).b(MgO).c(Al 2 O 3 ) (1)
[0000] or
[0000] a(M 2 O 1.5 ).b(MgO).c(Al 2 O 3 ) (2)
[0000] in which M 1 denotes at least one alkaline-earth metal, M 2 denotes yttrium or cerium and terbium in combination, and a, b and c are integers or non-integers that satisfy the relationships: 0.25≦a≦4; 0≦b≦2 and 0.5≦c≦9; in that M 1 and M 2 are partially substituted with europium and at least one other element belonging to the group of rare-earth metals, more particularly neodymium, terbium, cerium, dysprosium and gadolinium. The magnesium may be partially replaceable with Zn, Mn or Co, and the aluminium may be partially replaceable with Ga, Sc, B, Ge and Si.
[0029] According to another aspect of the invention, the luminophore is chosen from the group comprising (Ce 0.6 Tb 0.4 )MgAl 11 O 19 ; (Ba 0.9 Eu 0.1 )MgAl 10 O 17 ; Y 3 Al 5 O 12 :Eu 2+ ; Y 3 Al 5 O 12 :Ce 3+ ; Y 2 O 3 :Eu 3+ ; SrAl 12 O 19 :Mn 2+ ; Zn 2 SiO 4 :Mn 2+ .
[0030] According to yet another aspect of the invention, the luminophore is of the BAM, CAT, YAG or YOx type.
[0031] A subject of the invention is also a process for preparing via the alum route an aluminate luminophore as defined above in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 and 1.5 μm, comprising the following operations:
ammonium alum is mixed with at least one additive based on a rare-earth metal, this mixture is calcined at a first temperature of between 1100° C. and 1200° C., in particular 1150° C., for a time of between 1 hour and 2 hours, in particular 1 hour 30 minutes, the calcined mixture is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm, the calcined mixture is ground and passed through the screen, the ground mixture is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm, this ground and screened mixture is calcined at a second temperature of between 1300° C. and 1400° C., in particular 1350° C., for a time of between 3 hours and 5 hours, in particular 4 hours, the calcined mixture is ground, the ground mixture is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0040] According to another aspect, a magnesium sulfate heptahydrate is added to the mixture of the ammonium alum-additive based on a rare-earth metal.
[0041] According to another aspect, a final step of reduction with a gas containing hydrogen, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar, is added.
[0042] According to yet another aspect, the additive based on a rare-earth metal is a rare-earth metal nitrate M 3 (NO 3 ) 3 , M 3 being a rare-earth metal taken from the group formed by lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium.
[0043] According to another aspect for the preparation of BAM, anhydrous barium sulfate ground to d 50 <1 μm is added to the mixture comprising the ammonium alum, the additive based on a rare-earth metal and the magnesium sulfate heptahydrate.
[0044] A subject of the invention is also a process for preparing, via the alumina impregnation route, an aluminate luminophore as defined above in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 and 1.5 μm, comprising the following operations:
gamma alumina heated with a first solution heated to between 80° C. and 95° C., especially 90° C., is impregnated a first time with at least one additive based on a rare-earth metal, the impregnated gamma alumina is subjected to a first denitration heat treatment by heating to a first temperature of between 500° C. and 700° C., in particular 600° C., for a time of between 2 hours and 4 hours, in particular 3 hours, the result is passed through a grille made of non-contaminating material with a mesh size ≦500 μm, the impregnated, denitrated and screened alumina is ground, the ground mixture is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm, this ground and screened mixture is calcined at a temperature of between 1300° C. and 1400° C., in particular 1350° C., for a time of between 3 hours and 5 hours, in particular 4 hours, the result is ground, the result is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0053] According to a further aspect, after the first impregnation and the first denitration treatment:
the alumina impregnated and denitrated with a second solution heated to between 80° C. and 95° C., especially 90° C., is impregnated a second time with at least one additive based on a rare-earth metal, the impregnated gamma alumina is subjected to a second denitration heat treatment by heating to a first temperature of between 500° C. and 700° C., in particular 600° C., for a time of between 2 hours and 4 hours, in particular 3 hours.
[0056] According to yet another aspect, a final step of reduction with a gas containing hydrogen, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar, is added.
[0057] According to another aspect, the additive based on a rare-earth metal is a rare-earth metal nitrate M 3 (NO 3 ) 3 , M 3 being a rare-earth metal taken from the group formed by lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium.
[0058] For the preparation of the BAM, barium nitrate is added to the mixture comprising ammonium alum, the additive based on a rare-earth metal and the magnesium sulfate heptahydrate.
[0059] According to yet another aspect, the alumina is preheated to a temperature of between 80° C. and 150° C., especially 120° C., for a time of between 10 minutes and 2 hours.
[0060] As a variant, a subject of the invention is also a process for preparing via the impregnation route an aluminate luminophore as defined above in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 and 1.5 μm, comprising the following operations:
an alumina spinel heated with a first solution heated to between 80° C. and 95° C., especially 90° C., is impregnated with at least one additive based on a rare-earth metal, the impregnated alumina spinel is dried at a temperature of between 100° C. and 150° C., especially 120° C., for a time of between 3 hours and 5 hours, especially 4 hours, the dried result is passed through a grille made of non-contaminating material with a mesh size ≦500 μm, the impregnated alumina spinel is subjected to a denitration heat treatment by heating to a first temperature of between 500° C. and 700° C., in particular 600° C., for a time of between 2 hours and 4 hours, in particular 3 hours, the impregnated and denitrated alumina spinel is ground, the ground mixture is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm, this ground and screened mixture is calcined at a temperature of between 1300° C. and 1400° C., in particular 1350° C., for a time of between 3 hours and 5 hours, in particular 4 hours, the result is ground, the ground result is passed through a grille made of non-contaminating material with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0070] According to yet another aspect, for the preparation of the BAM, barium nitrate is added to the mixture comprising the alumina spinel-additive based on a rare-earth metal.
[0071] According to yet another aspect, a final step of reduction with a gas containing hydrogen, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar, is added.
[0072] According to yet another aspect, the additive based on a rare-earth metal is a rare-earth metal nitrate M 3 (NO 3 ) 3 , M 3 being a rare-earth metal taken from the group formed by lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium.
[0073] According to yet another aspect, the alumina spinel is preheated to a temperature of between 80° C. and 150° C., especially 120° C., for a time of between 10 minutes and 2 hours.
[0074] A subject of the invention is also the use of a luminophore as defined above in the manufacture of display screens, lighting, projectors, in particular plasma screens or field-emission screens, backlight lamps for liquid-crystal screens, light-emitting diodes, plasma-excitation light bulbs and trichromatic bulbs.
[0075] A subject of the invention is also an alumina-luminophore mixed compound comprising between 50% and 95% of alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape as defined above and between 5% and 50% of a luminophore.
[0076] According to one aspect of this mixed compound, the luminophore is a luminophore as defined above.
[0077] According to another aspect, the luminophore is an aluminate in the form of a composition corresponding to the formula:
[0000] a(M 1 O).b(MgO).c(Al 2 O 3 ) (1)
[0000] or
[0000] a(M 2 O 1.5 ).b(MgO).c(Al 2 O 3 ) (2)
[0000] in which M 1 denotes at least one alkaline-earth metal, M 2 denotes yttrium or cerium and terbium in combination, and a, b and c are integers or non-integers that satisfy the relationships: 0.25≦a≦4; 0≦b≦2 and 0.5≦c≦9; in that M 1 and M 2 are partially substituted with europium and at least one other element belonging to the group of rare-earth metals, more particularly neodymium, terbium, cerium, dysprosium and gadolinium. The magnesium may be partially replaceable with Zn, Mn or Co, and the aluminium may be partially replaceable with Ga, Sc, B, Ge and Si.
[0078] According to another aspect of the invention, the luminophore is chosen from the group comprising (Ce 0.6 Tb 0.4 )MgAl 11 O 19 ; (Ba 0.9 Eu 0.1 )MgAl 10 O 17 ; Y 3 Al 5 O 12 :Eu 2+ ; Y 3 Al 5 O 12 :Ce 3+ ; Y 2 O 3 :Eu 3+ ; SrAl 12 O 19 :Mn 2+ ; Zn 2 SiO 4 :Mn 2+ .
[0079] A subject of the invention is also a process for preparing a mixed compound as defined above, in which:
between 50% and 95% of alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape and between 5% and 50% of a luminophore are mixed together; the mixture is ground.
[0082] A subject of the invention is also the use of the compound as defined above in the manufacture of display screens, lighting, projectors, in particular plasma screens or field-emission screens, backlight lamps for liquid-crystal screens, light-emitting diodes, plasma-excitation light bulbs and trichromatic bulbs.
[0083] A subject of the invention is also an aqueous suspension for producing a coating for fluorescent lamps, especially fluorescent tubes comprising at least one mixed compound as defined above, polyethylene oxide, gamma alumina obtained from the alum route and demineralized water.
[0084] According to one aspect of the aqueous suspension, the weight proportions are:
25% to 50% of at least one mixed compound as defined above, 0.5% to 5% of polyethylene oxide, 0.3% to 1.5% of gamma alumina obtained from the alum route, and the remainder being demineralized water.
[0089] According to another aspect of the aqueous suspension, it comprises three mixed compounds forming a trichromatic assembly.
[0090] According to another aspect of the aqueous suspension, the three mixed compounds are present in weight proportions of:
between 35% and 40%, preferably 38%, of mixed compound (Ce 0.6 Tb 0.4 )MgAl 11 O 19 -alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape; between 10% and 15%, preferably 12%, of mixed compound (Ba 0.9 Eu 0.1 )MgAl 10 O 17 -alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape; and the remainder being the mixed compound Y 2 O 3 :Eu 3+ -alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape.
[0094] Other characteristics and advantages of the invention will emerge from the following description, which is given by way of example, with no limiting nature, with regard to the attached figures, in which:
[0095] FIG. 1 is an electron microscope photograph of an alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape,
[0096] FIG. 2 shows several diffraction spectra during the manufacture of a BAM,
[0097] FIG. 3 shows several diffraction spectra during the manufacture of a CAT, and
[0098] FIG. 4 shows several diffraction spectra during the manufacture of a YAG.
DETAILED DESCRIPTION
[0099] For all the grinding operations, a unit amount is treated in a ball mill (for example a Sweco® brand batch mill of DM1 type) with alumina milling beads. The amount of alumina beads is at least ten times greater than the unit amount. In general, an amount of alumina milling beads 20 times greater than the unit amount to be treated was adopted to limit the milling time and to optimize the screening time.
[0100] For the screening operations, a screen made of a non-contaminating material, for example of plastic, especially of polyamide, was chosen to avoid any contamination of the undersize. For example, the term “200 μm screen or grille” means a screen whose screening mesh has an undersize of 200 μm.
[0101] For the calcination operations, a gas-fired tunnel oven whose maximum temperature is 1200° C. and whose residence time is variable between 1 hour and 3 hours and a gas-fired batch oven whose maximum temperature is 1400° C. and whose residence time is adaptable are used.
[0102] The spectral measurements were performed with an X-ray diffractometer: Rigaku®—model D/Max2200
[0103] The photograph of the alpha alumina was taken with an electron microscope: Philips®—series XL—model XL30.
[0104] The particle size measurements were taken either using a Micromeritics® brand Sedigraph granulometer type 5100 series 809, or with a Horiba® brand laser-scattering granulometer type LA920.
1. Alpha Alumina
[0105] One subject of the invention is an alpha alumina with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape.
[0106] The diameter d 50 is defined as being the particle diameter for which 50% of the volume of the population is formed from particles with a diameter smaller than this value.
[0107] Such an alumina is shown in FIG. 1 as an electron microscope photograph. It is seen therein that these particles have a substantially spherical or ellipsoid shape, i.e. there are virtually no edges.
[0108] Such alpha alumina particles are particularly suitable for use as matrix for luminophores, especially in a coating, for example an alumina-luminophore monolayer for fluorescent lamps.
[0109] Specifically, it turns out that, in fluorescent lamps, such alumina particles have increased efficacy as reflectors of the ultraviolet light derived from excitation of the gas mixture by the electrodes and allow this ultraviolet light to be coupled more efficiently to the luminophore particles.
[0110] This novel alumina with better properties in terms of reflection and of coupling of light in luminophores is made, for example, according to the following preparation process:
[0111] According to a first step, gamma alumina obtained via the alum route, a sintering agent and alpha alumina seeds are mixed together. The sintering agent is, for example, NH 4 F.
[0112] For this process, the term “gamma alumina obtained via the alum route” means an alumina whose crystal structure is predominantly composed of gamma alumina, especially to more than 80% or even 90% of gamma alumina.
[0113] For this process, the term “alpha alumina seeds” means pure seeds of alpha alumina or predominantly composed of alpha alumina, especially to more than 80% or even 90% of alpha alumina.
[0114] The mixture is, for example, composed, as weight proportions, of 85% to 95% gamma alumina obtained via the alum route, 2.5% to 13% alpha alumina and 0.4% to 1.8% NH 4 F, more specifically, the mixture is composed, as weight proportions, of about 93.5% gamma alumina obtained via the alum route, of about 5.5% alpha alumina and of about 1% NH 4 F.
[0115] Next, according to a second step, the mixture is calcined in an oven at a temperature of between 1150° C. and 1400° C., especially 1350° C., for a time of between 1 hour and 6 hours, especially 2 hours.
[0116] During a third step, the calcined mixture is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the calcined mixture, for a time of between 8 hours and 30 hours, especially 16 hours.
[0117] More specifically, the calcined mixture can be ground in a ball mill with alumina milling beads at least twenty times greater in amount than the calcined mixture, for 16 hours.
[0118] In a fourth step, the ground mixture is passed through a grille made of a non-contaminating material, for example plastic, preferably polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
EXAMPLE 1
[0119] To obtain about 1 kg of alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape, 1000 g of gamma alumina sold under the name Baikalox® B105, 60 g of alpha alumina sold under the name Baikalox® BMA15 and 10 g of NH 4 F were mixed together.
[0120] The alumina BMA15 has the particular feature in that its crystal structure is 100% composed of alpha alumina with a diameter d 50 of about 150 nm.
[0121] In a second step, this mixture was then calcined at a temperature of 1350° C. for 2 hours.
[0122] In a third step, the calcined mixture was ground in a ball mill with milling beads. The alumina milling beads have a diameter of about a centimetre, especially between 3 cm and 5 cm. The amount of milling beads relative to the calcined mixture was 20.
[0123] During the fourth and final step, the result after grinding was passed through a polyamide screen with a mesh size of 200 μm.
[0124] FIG. 1 shows the result obtained.
[0125] According to another test during which the calcination temperature was 1200° C. for 4 hours during the second step, alpha alumina particles with a size d 50 of 1 μm and a substantially spherical shape were obtained with good homogeneity. It was found that a lower calcination temperature with a longer residence time gives better size homogeneity of the spherical alumina particles.
2. Aluminate Luminophore
[0126] A subject of the invention is also aluminate luminophores in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 μm and 1.5 μm. The term “mean size” generally means the diameter d 50 defined above.
[0127] These luminophores are aluminates in the form of a composition corresponding to the formulae:
[0000] a(M 1 O).b(MgO).c(Al 2 O 3 ) (1)
[0000] or
[0000] a(M 2 O 1.5 ).b(MgO).c(Al 2 O 3 ) (2)
[0000] in which M 1 denotes at least one alkaline-earth metal, M 2 denotes yttrium or cerium and terbium in combination, and a, b and c are integers or non-integers that satisfy the relationships: 0.25≦a≦4; 0≦b≦2 and 0.5≦c≦9; in that M 1 and M 2 are partially substituted with europium and at least one other element belonging to the group of rare-earth metals, more particularly neodymium, terbium, cerium, dysprosium and gadolinium. The magnesium may be partially replaceable with Zn, Mn or Co, and the aluminium may be partially replaceable with Ga, Sc, B, Ge and Si.
[0128] According to another aspect of the invention, the luminophore is chosen from the group comprising (Ce 0.6 Tb 0.4 )MgAl 11 O 19 ; (Ba 0.9 Eu 0.1 )MgAl 10 O 17 ; Y 3 Al 5 O 12 :Eu 2+ ; Y 3 Al 5 O 12 :Ce 3+ ; Y 2 O 3 :Eu 3+ ; SrAl 12 O 19 :Mn 2+ ; Zn 2 SiO 4 :Mn 2+ .
[0129] BAM, CAT and YOx have visible emission spectra in the blue, green and red regions, respectively, which, on mixing, makes it possible to produce trichromatic bulbs. As individual luminophores, they make it possible, for example, to produce screen pixels or emissive diodes.
[0130] For the preparation of these novel specific luminophores, three alternative preparation processes are proposed.
2.1 Preparation of an Aluminate Luminophore Via the Alum Route
[0131] According to a process for preparing an aluminate luminophore via the alum route as defined above, which is in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 and 1.5 μm, the following operations were performed.
[0132] In a first step, ammonium alum is mixed with at least one additive based on a rare-earth metal.
[0133] The additive based on a rare-earth metal is a rare-earth metal nitrate M 3 (NO 3 ) 3 , M 3 being a rare-earth metal taken from the group formed by lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium.
[0134] As a function of the luminophore, there may be a single rare-earth metal nitrate [for example in the manufacture of BAM of Eu(NO 3 ) 3 ] or several [for example Tb(NO 3 ) 3 and Ce(NO 3 ) 3 for the manufacture of CAT].
[0135] According to one particular aspect for the preparation of BAM, anhydrous barium sulfate ground to d 50 <1 μm is also added.
[0136] To this mixture, in particular for the manufacture of BAM and CAT, there may be reason also to add magnesium sulfate heptahydrate (MgSO 4 .7H 2 O) which is commercially available in high chemical purity. The sulfate is the salt that is compatible with ammonium alum in this process and in particular compatible with the treatment of the oven outlet gases.
[0137] In a second step, this mixture is calcined at a first temperature of between 1100° C. and 1200° C., in particular 1150° C., for a time of between 1 hour and 2 hours, in particular 1 hour 30 minutes.
[0138] In a third step, the calcined mixture is passed through a grille made of a non-contaminating material, for example plastic, especially polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0139] In a fourth step, the calcined mixture passed through the screen is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the calcined precursor, for between 8 hours and 30 hours.
[0140] Next, in a fifth step, the ground mixture is passed through a grille made of a non-contaminating material, for example plastic, especially polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0141] In a sixth step, this ground mixture is calcined at a second temperature of between 1300° C. and 1400° C., in particular 1350° C., for a time of between 3 hours and 5 hours, in particular 4 hours.
[0142] In a seventh step, the result is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount that the calcined precursor, for between 8 hours and 30 hours.
[0143] In an eighth step, the result is passed through a grille made of a non-contaminating material, for example plastic, especially polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0144] According to a ninth step as a function of the type of luminophore, in particular for BAM and CAT, a final step of reduction with a gas containing hydrogen is performed, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar.
EXAMPLE 2
Process for Preparing BAM Via the Alum Route
[0145] To obtain about 1 kg of BAM:EU (Ba 0.9 Eu 0.1 )MgAl 10 O 17 , the following are mixed together in a first step:
5833 g of ammonium alum, 270 g of anhydrous barium sulfate (BaSO 4 ) ground to d 50 <1 μ, 308 g of magnesium sulfate heptahydrate (MgSO 4 .7H 2 O), and 106.8 ml of a europium nitrate solution (Eu(NO 3 ) 3 ) at 233 g of oxide/I.
[0150] In a second step, this mixture is calcined at a first temperature of 1150° C. for a time of 1 hour 30 minutes.
[0151] In a third step, this calcined mixture is passed through a grille made of polyamide plastic with a mesh size of 200 μm.
[0152] In a fourth step, the calcined mixture passed through the screen is ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 8 hours.
[0153] In a fifth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0154] In a sixth step, this ground and screened mixture is calcined at a second temperature of 1350° C. for a time of 4 hours.
[0155] In a seventh step, the result obtained is ground in a ball mill with milling beads in an amount twenty times greater than the calcined result, for 8 hours.
[0156] In an eighth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0157] In an ninth step, a final step of reduction is performed with a gas containing hydrogen, for example a mixture (95% N 2 and 5% H 2 ) with a temperature rise of 14° C./minute, and a steady stage of at least 1 hour at a temperature of 1600° C. at a pressure of about 100 mbar.
EXAMPLE 3
Process for Preparing CAT Via the Alum Route
[0158] To obtain about 1 kg of CAT (Ce 0.6 Tb 0.4 )MgAl 11 O 19 , the following are mixed together in a first step:
6400 g of ammonium alum containing 11.25% oxide, 335.64 g of crystalline Ce(NO 3 ) 3 containing 39.5% oxide, 423.22 g of a Tb(NO 3 ) 3 solution containing 22.68% oxide, 315.55 g of crystalline MgSO 4 .7H 2 O containing 16.4% oxide.
[0163] In a second step, this mixture is calcined at a first temperature of 1150° C. for a time of 1 hour 30 minutes (see the diffraction spectrum of FIG. 3 : CAT precursor 1150° C.).
[0164] In a third step, this calcined mixture is passed through a grille made of polyamide plastic with a mesh size of 200 μm.
[0165] In a fourth step, the calcined mixture passed through the screen is ground with alumina milling beads in an amount twenty times greater than the calcined result, for 8 hours.
[0166] In a fifth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0167] In a sixth step, this ground and screened mixture is calcined at a second temperature of 1350° C. for a time of 4 hours (see the diffraction spectrum of FIG. 3 : calcined CAT 1350° C.).
[0168] In a seventh step, the result obtained is ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 8 hours.
[0169] In an eighth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0170] In a ninth step, a final step of reduction is performed with a gas containing hydrogen, for example a mixture (95% N 2 and 5% H 2 ) with a temperature rise of 14° C./minute, and a steady stage of at least 1 hour at a temperature of 1600° C. at a pressure of about 100 mbar (see the diffraction spectrum of FIG. 3 : reduced CAT).
[0171] The diffraction spectrum of the reduced product does not show any crystalline species other than the CAT luminophore.
EXAMPLE 4
Process for Preparing YAG Via the Alum Route
[0172] To obtain about 1 kg of YAG:Ce, i.e. Y 3 Al 5 O 12 :Ce 3+ , the following are mixed together in a first step:
3833 g of ammonium alum, 570 g of an yttrium nitrate solution Y(NO 3 ) 3 at 359 g/l, 4.4 g of a cerium nitrate solution Ce(NO 3 ) 3 at 19.2%.
[0176] In a second step, this mixture was calcined at a first temperature of 1150° C. for a time of 1 hour 30 minutes (see the diffraction spectrum of FIG. 4 : YAG precursor 1150° C.).
[0177] In a third step, this calcined mixture was passed through a polyamide plastic grille with a mesh size of 200 μm.
[0178] In a fourth step, the calcined mixture passed through the screen was ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 8 hours.
[0179] In a fifth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0180] In a sixth step, this ground and screened mixture is calcined at a second temperature of 1350° C. for a time of 4 hours (see the diffraction spectrum of FIG. 3 : calcined YAG 1350° C.).
[0181] In a seventh step, the result obtained was ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 8 hours.
[0182] In an eighth step, the ground mixture was passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0183] The diffraction spectrum does not reveal any crystalline species other than the YAG luminophore.
[0184] It will be noted that, according to the same process, YAGs doped with Eu 3+ , Tb 4+ or Gd 3+ , and mixtures of the last two dopants, may be produced. It will be noted that, according to the same process, YAGs doped with Ni 2+ , V 2+ , Co 2+ , which require a final reduction step according to the protocol defined previously, may be produced.
[0185] More generally, the YAGs may be doped to between 0.1% and 5% with cations of transition elements, in their oxidized or reduced form. The alum route is particularly suitable for incorporating them into the cubic lattice of YAG.
2.2. Preparation Via the Impregnation Route of a Gamma Alumina of an Aluminate Luminophore
[0186] As an alternative to the alum route, a process is proposed for the preparation via the impregnation route of an aluminate luminophore as defined above in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 and 1.5 μm.
[0187] In a first step of this process, gamma alumina heated with a first solution of barium and magnesium alkaline-earth metal salts, heated to between 80° C. and 95° C. and especially 90° C., is impregnated a first time with at least one additive based on a rare-earth metal.
[0188] The additive based on a rare-earth metal is a rare-earth metal nitrate M 3 (NO 3 ) 3 , M 3 being a rare-earth metal alone or a mixture taken from the group formed by lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium.
[0189] For the preparation of the BAM, the impregnation solution comprises, besides the additive based on a rare-earth metal, magnesium sulfate and barium nitrate.
[0190] For the preparation of the CAT, besides the additive based on a rare-earth metal, magnesium sulfate is added to the mixture of the ammonium alum-impregnation solution.
[0191] This impregnation is found to be improved when the alumina is preheated to a temperature of between 80° C. and 150° C., especially 120° C., for a time of between 10 minutes and 2 hours.
[0192] In a second step, the impregnated gamma alumina is subjected to a first denitration heat treatment by heating to a first temperature of between 500° C. and 700° C., in particular 600° C., for a time of between 2 hours and 4 hours, in particular 3 hours.
[0193] In a third step, the impregnated and denitrated alumina is passed through a grille made of a non-contaminating material, for example plastic, especially polyamide, with a mesh size ≦500 μm. This step makes it possible to avoid any residual crucible bits that it is not desired to entrain into the following grinding step.
[0194] In a fourth step, the result is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the impregnated and denitrated alumina, for between 8 hours and 30 hours.
[0195] In a fifth step, this ground mixture is calcined at a temperature of between 1300° C. and 1400° C., in particular 1350° C., for a time of between 3 hours and 5 hours, in particular 4 hours.
[0196] In a sixth step, the result is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the calcined precursor, for between 8 hours and 30 hours.
[0197] In a seventh step, the result is passed through a grille made of a non-contaminating material, for example plastic, especially polyamide, with a screen size of between 150 μm and 250 μm, especially 200 μm.
[0198] In an eighth step, as a function of the type of luminophore (for example for BAM and CAT), a final reduction step is performed with a gas containing hydrogen, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar.
[0199] In particular for BAM, it is found to be judicious to add a second impregnation.
[0200] Consequently, after the first impregnation and the first denitration treatment, the following steps may be inserted, consisting in:
impregnating a second time the impregnated and denitrated alumina in a second solution heated to between 80° C. and 95° C., especially 90° C., with at least one additive based on a rare-earth metal, subjecting the impregnated gamma alumina to a second denitration heat treatment by heating to a first temperature of between 500° C. and 700° C., in particular 600° C., for a time of between 2 hours and 4 hours, in particular 3 hours.
EXAMPLE 5
Process for Preparing BAM Via the Gamma Alumina Impregnation Route
[0203] To obtain about 1 kg of BAM, in a first step of this process, 750 g of gamma alumina (commercially available as Baikalox® B105 with a 100% gamma crystal structure and a mean size d 50 of about 6 μm) heated to 120° C. were impregnated a first time with 1825 ml of a solution heated to 90° C., containing:
205.3 g of barium nitrate containing 59.3% oxide, 254.16 g of magnesium nitrate hexahydrate containing 14% oxide, and 39.42 g of europium nitrate containing 39.4% oxide.
[0207] Next, in a second step, the impregnated gamma alumina is subjected to a first denitration heat treatment by heating to a first temperature of 600° C. for a time of 3 hours.
[0208] In a third step, the impregnated and denitrated alumina is impregnated a second time with 1125 ml of a solution heated to 90° C., containing:
136.9 g of barium nitrate containing 59.3% oxide, 169.44 g of magnesium nitrate hexahydrate containing 14% oxide, and 26.28 g of europium nitrate containing 39.4% oxide.
[0212] In a fourth step, the impregnated gamma alumina is subjected to a second denitration heat treatment by heating at a first temperature of 600° C. for a time of 3 hours (see the diffraction spectrum of FIG. 2 , precursor BAM 600° C.).
[0213] In a fifth step, the result is ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 16 hours.
[0214] In a sixth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0215] In a seventh step, this ground mixture is calcined at a temperature of 1350° C. for a time of 3 hours (see the diffraction spectrum of FIG. 2 , BAM calcined 1350° C.).
[0216] In an eighth step, the result is ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 16 hours.
[0217] In a ninth step, the result is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0218] In a tenth step, a final reduction step is performed with a gas containing hydrogen, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar (see the diffraction spectrum of FIG. 2 , reduced BAM).
EXAMPLE 6
Process for Preparing CAT Via the Gamma Alumina Impregnation Route
[0219] To obtain about 1 kg of CAT, in a first step of this process, 720 g of gamma alumina (commercially available as Baikalox® B105 and having a 100% gamma crystal structure and a mean size d 50 of about 6 μm) were impregnated with a solution of:
360 ml of a Ce(NO 3 ) 3 solution containing 368.3 g/l of oxide, 258 ml of a Tb(NO 3 ) 3 solution containing 372 g/l of oxide, 576 ml of an MgSO 4 solution containing 89.8 g/l of oxide.
[0223] Next, in a second step, the impregnated gamma alumina is subjected to a first denitration heat treatment by heating at a first temperature of 600° C. for a time of 3 hours.
[0224] In a third step, the result is ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 16 hours.
[0225] In a fourth step, the ground mixture is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0226] In a fifth step, this ground mixture is calcined at a temperature of 1350° C. for a time of 3 hours (see the diffraction spectrum of FIG. 2 , BAM calcined 1350° C.).
[0227] In a sixth step, the result is ground in a ball mill with alumina milling beads in an amount twenty times greater than the calcined result, for 16 hours.
[0228] In a seventh step, the ground result is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0229] In an eighth step, a final reduction step is performed with a gas containing hydrogen, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar (see the diffraction spectrum of FIG. 2 , reduced BAM).
2.3 Preparation Via the Impregnation Route of an Alumina Spinel of an Aluminate Luminophore
[0230] As a variant, a process is also proposed for the preparation via the impregnation route of an alumina spinel of an aluminate luminophore as defined above in the form of aggregates with a mean size of about 10 μm, these aggregates being composed of particles with a mean size of between 0.25 and 1.5 μm. This process comprises the following operations:
[0231] According to a first step, an alumina spinel heated with a first solution heated to between 80° C. and 95° C., especially 90° C., is impregnated with at least one additive based on a rare-earth metal.
[0232] Such alumina spinels have been described in document U.S. Pat. No. 6,251,150.
[0233] It proves to be judicious for the alumina spinel to be heated beforehand at a temperature of between 80° C. and 150° C., especially 120° C., for a time of between 10 minutes and 2 hours.
[0234] The additive based on a rare-earth metal is, for example, a rare-earth metal nitrate M 3 (NO 3 ) 3 , M 3 being a rare-earth metal alone or as a mixture taken from the group formed by lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium.
[0235] For the preparation of BAM, barium nitrate is added to the impregnation solution of the alumina spinel containing the additive based on a rare-earth metal.
[0236] According to a second step, the impregnated alumina spinel is dried at a temperature of between 100° C. and 150° C., especially 120° C., for a time of between 3 hours and 5 hours, especially 4 hours.
[0237] Next, according to a third step, the dried result is passed through a grille made of a non-contaminating material, for example of plastic, especially of polyamide, with a mesh size ≦500 μm.
[0238] According to a fourth step, the impregnated alumina spinel is subjected to denitration heat treatment by heating at a first temperature of between 500° C. and 700° C., in particular 600° C., for a time of between 2 hours and 4 hours, in particular 3 hours.
[0239] According to a fifth step, the impregnated and denitrated alumina spinel is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the calcined precursor, for between 8 hours and 30 hours.
[0240] According to a sixth step, the ground result is passed through a grille made of a non-contaminating material, for example of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0241] According to a seventh step, this ground and screened mixture is calcined at a temperature of between 1300° C. and 1400° C., in particular 1350° C., for a time of between 3 hours and 5 hours, in particular 4 hours.
[0242] According to an eighth step, the result is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the calcined precursor, for between 8 hours and 30 hours, in particular 16 hours.
[0243] According to a ninth step, the ground result is passed through a grille made of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0244] According to yet another aspect, as a function of the luminophore, a final tenth step of reduction with a gas containing hydrogen is added, with a temperature rise of between 10° C.-20° C./minute, especially 14° C./minute, and a steady stage of at least 1 hour at a temperature of between 1500° C. and 1600° C. at a pressure of about 100 mbar.
EXAMPLE 7
Process for Preparing BAM Via the Alumina Spinel Impregnation Route
[0245] To obtain about 1 kg of BAM, according to a first step, 750 g of alumina spinel (5Al 2 O 3 .MgO) preheated to a temperature of 120° C. were impregnated with 1.66 litres of a solution heated to 90° C., containing:
320.75 g of barium nitrate containing 59.3% oxide, and 98 ml of a europium nitrate solution containing 247.4 g of oxide/I.
[0248] Such alumina spinels have been described in document U.S. Pat. No. 6,251,150, but may also be obtained by mixing, while respecting the proportions, 7000 g of ammonium alum and 376.7 g of Mg(SO 4 ).7H 2 O and by calcining this mixture at a temperature of between 1100° C. and 1200° C., especially 1150° C., for a time of between 1 hour and 2 hours, especially 1 hour 30 minutes.
[0249] According to a second step, the impregnated alumina spinel was dried at a temperature of 120° C. for a time of 4 hours.
[0250] Next, according to a third step, the dried result was passed through a grille made of plastic, especially of polyamide, with a mesh size ≦500 μm.
[0251] According to a fourth step, the impregnated alumina spinel was subjected to a denitration heat treatment by heating at a first temperature of 600° C. for a time of 3 hours.
[0252] According to a fifth step, the impregnated and denitrated alumina spinel was ground in a ball mill with alumina milling beads in an amount twenty times greater than the result, for 16 hours.
[0253] According to a sixth step, the ground result was passed through a grille made of plastic, especially of polyamide, with a mesh size of 200 μm.
[0254] According to a seventh step, this ground and screened mixture was calcined at a temperature of 1350° C., for a time of 4 hours.
[0255] According to an eighth step, the result was ground in a ball mill with alumina milling beads in an amount twenty times greater than the result, for 16 hours.
[0256] According to a ninth step, the ground result was passed through a grille made of plastic, especially of polyamide, with a mesh size of 200 μm.
[0257] According to a final tenth step, the result was reduced with a gas composed of 95% N 2 and 5% H 2 , with a temperature rise of 14° C./minute and a steady stage of one hour at a temperature of 1600° C. at a pressure of about 100 mbar.
[0258] The luminophores as defined above may be used in the manufacture of display screens, lighting (fluorescent lamps), projectors, in particular plasma screens or field-emission screens, backlight lamps for liquid-crystal screens, light-emitting diodes, plasma-excitation light bulbs and trichromatic bulbs.
3. Alumina-Luminophore Mixed Compound
[0259] In particular for the manufacture of monolayer fluorescent lamps, an alumina-luminophore mixed compound is proposed, comprising between 50% and 95% of alpha alumina with a size d 50 of between 0.3 μm and 2 μm and a spherical shape as defined above, and between 5% and 50% of a luminophore.
[0260] The luminophore is an aluminate in the form of a composition corresponding to the formula:
[0000] a(M 1 O).b(MgO).c(Al 2 O 3 ) (1)
[0000] or
[0000] a(M 2 O 1.5 ).b(MgO).c(Al 2 O 3 ) (2)
[0000] in which M 1 denotes at least one alkaline-earth metal, M 2 denotes yttrium or cerium and terbium in combination, and a, b and c are integers or non-integers that satisfy the relationships: 0.25≦a≦4; 0≦b≦2 and 0.5≦c≦9; in that M 1 and M 2 are partially substituted with europium and at least one other element belonging to the group of rare-earth metals, more particularly neodymium, terbium, cerium, dysprosium and gadolinium. The magnesium may be partially replaceable with Zn, Mn or Co, and the aluminium may be partially replaceable with Ga, Sc, B, Ge and Si.
[0261] According to another aspect of the invention, the luminophore is chosen from the group comprising (Ce 0.6 Tb 0.4 )MgAl 11 O 19 ; (Ba 0.9 Eu 0.1 )MgAl 10 O 17 ; Y 3 Al 5 O 12 :Eu 2+ ; Y 3 Al 5 O 12 :Ce 3+ ; Y 2 O 3 :Eu 3+ ; SrAl 12 O 19 :Mn 2+ ; Zn 2 SiO 4 :Mn 2+ .
[0262] As luminophore, it is possible to use commercial luminophores and this mixed compound has a reduced cost for equivalent performance qualities as a result of its composition. This is possible by virtue of the better reflection properties of the alpha alumina particles.
[0263] It is even more preferable to use a luminophore as defined above in points 2, 2.1, 2.2 and 2.3.
[0264] This mixed compound may be prepared via a preparation process in which:
between 50% and 95% of alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a substantially spherical shape and between 5% and 50% of a luminophore are mixed together, the mixture is ground, for example in a ball mill with alumina milling beads at least ten times greater in amount than the mixture, for between 8 hours and 30 hours, the ground result is passed through a grille made of a non-contaminating material, for example of plastic, especially of polyamide, with a mesh size of between 150 μm and 250 μm, especially 200 μm.
[0268] According to one variant, milling of air-jet type may be envisaged, for example with an “Alpine”-type plate air-jet mill.
[0269] A subject of the invention is also the use of the mixed compound as defined above in the manufacture of display screens, lighting, projectors, in particular plasma screens or field-emission screens, backlight lamps for liquid-crystal screens, light-emitting diodes, plasma-excitation light bulbs and trichromatic bulbs.
[0270] A subject of the invention is also an aqueous suspension for producing a coating for fluorescent lamps, especially fluorescent tubes comprising at least one mixed compound as defined above, polyethylene oxide, gamma alumina obtained from the alum route and demineralized water.
[0271] The weight proportions in the aqueous solution are:
25% to 50% of at least one mixed compound as defined above, 0.5% to 5% of polyethylene oxide, 0.3% to 1.5% of gamma alumina obtained from the alum route, and the remainder being demineralized water.
[0276] This aqueous solution may comprise three different mixed compounds forming a trichromatic assembly.
[0277] For example, the three mixed compounds may be present in weight proportions of:
between 35% and 40%, preferably 38%, of mixed compound (Ce 0.6 Tb 0.4 )MgAl 11 O 19 -alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape; between 10% and 15%, preferably 12%, of mixed compound (Ba 0.9 Eu 0.1 )MgAl 10 O 17 -alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape; and the remainder being the mixed compound Y 2 O 3 :Eu 3+ -alpha alumina composed essentially of particles with a size d 50 of between 0.3 μm and 2 μm and a spherical shape.
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The present invention relates to the synthesis of luminophores and of reflective alumina for optimizing the emissive properties of a fluorescent layer.
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BACKGROUND OF THE INVENTION
This invention relates to an improved mixing system having particular use in preparing a spray dampening fluid of the type employed in offset printing. More particularly the mixing system accurately controls the amount of dampening fluid and water mixture and provides a continuous cycling system offering a constant pressurized flow of dampening fluid mixture. The mixing system is useful in providing the spray dampening fluid for the spraying system of copending application Ser. No. 518,470, filed July 29, 1983, entitled "Variable Frequency Spray Dampening System.".
In manufacturing systems which require continuous batch mixing and feeding of chemicals for a subsequent processing step, it is most often desirable to provide a mixing system which can offer a constant influent rate and which at the same time can continuously mix chemicals in desired proportions.
Complex proportional mixing systems using liquid motor drives and metering pumps, such as lost motion pumps, exist in the art but it would be highly desirable to attain an effective and reliable mixing system which is simplified and greatly reduces equipment supervision that otherwise results with the more complicated mixing systems.
A particular need in the offset printing business involves dampening the printing rolls with a water-etch mixture to enable them to be activated for reception of ink in a well-known manner. Therefore, the invention is directed for use in such spray dampening systems, but also has wide utility in other industrial processes requiring the continuous feed and constant flow of chemicals mixed in pre-selected proportions.
SUMMARY OF THE INVENTION
The present invention is a simplified but improved, liquid mixing system that provides automatic recycling which can constantly discharge the mixed chemicals at a constant flow rate on damand in tandem operation with a separate system or process, such as spray dampening equipment for offset printing rolls.
In summary of the invention, there is provided a liquid containment means in the form of a batch mixer preferably vertically stacked above a feed tank. The mixer and feed tank communicate therebetween, such as by means of an intermediate valve. A normally closed first valve communicates with the batch mixer and with feed lines from a first or parent liquid source and feed lines from at least one second or additive liquid source. At the initiation of a mixing operation, and during cyclical continuous operation, a low limit sensing means, disposed interiorly of the mixer, signals that fluid in the mixer is below a predetermined level. The low limit sensing means is part of a sequence control means and responsively signals the first valve to open for influence of the first liquid from a normally closed supply valve associated with the first liquid supply source and which is activated to open. Upon filling the batch mixer to a predetermined level, a high limit sensing means is activated and the sequence control means responsively signals the supply valve to close and thereby terminate the influence of the first liquid. A mixer motor having mixing blades interiorly of the batch mixer is then started. At the same time, the control means initiates the admittance of a second liquid by opening a supply valve associated with a second liquid supply source. The second liquid enters the batch mixer through the open first valve. Within the mixer there is an electrical conductivity sensing means which is also part of the control means. This sensing means senses when a pre-set conductivity is reached whereupon the second liquid supply valve is de-activated and closes. The mixer motor continues mixing for a pre-set duration and then is de-activated. The first valve is then closed. A three-way air valve, associated with an air pressure source communicating with the batch mixer, is signalled to open to introduce air from a pressurized feed line into the batch mixer and pressurize the mixer. When pressurized, intermediate valve means and an air pressure by-pass valve, both separately communicating between the batch mixer and stacked feed tank, are activated to open. The mixed first and second liquids are transferred under pressure into the feed tank.
The feed tank is also in communication with a source of pressurized air, which is controlled by another three-way air valve. This air valve opens responsively to a low limit sensor when fluid is above a predetermined level in the feed tank. At start-up, when the feed tank level may be below the sensing means, the feed tank is not pressurized. In this case, the by-pass valve serves to equilibrate the air pressure when opened in order that the feed tank is immediately pressurized and ready to supply the water-etch mix under pressure through a discharge pressure regulator at the bottom of the tank. During continuous operation, the feed tank is pressurized when the intermediate valve opens, and displaced air flows up through the by-pass valve from the feed tank into the batch mixer as the fluid is transferred.
The low limit sensing means in the feed tank responds to the entering liquid and at a pre-set level signal the sequence control means to pressurize the feed tank by means of opening the three way air valve associated with the air pressure source. The air pressure source communicates with the feed tank by a feed line which is separate from the feed line serving the batch mixer. The discharge pressure regulator opens upon reaching a pre-set pressurization level and liquid in the feed tank is discharged into a supply line which conveys the liquid to a spray dampening system.
As mixed liquids in the batch mixer are transferred to the feed tank, the level drops to the low limit sensing means which then signals the sequence control means, and the intermediate valve means is closed. Then, the sequence control means activates the mixer air valve to switch to an exhaust position and de-pressurize the mixer. In sequence the first valve and supply valve for the first liquid are again opened for a next cycle. Continuous outlet discharge from the feed tank is maintained while the next mixing cycle in the batch mixer takes place, since the feed tank remains pressurized when fluid level therein remains above the low limit sensor.
In an alternative embodiment, pumps may be substituted for air pressurization. One pump, in replacement of the intermediate valve means, would communicate with the batch mixer for transfer of the mixed fluids to the feed tank. A second pump, in replacement of the feed tank pressure regulator, would discharge the mixed liquids into the supply line of the spray dampening system at a constant flow rate and pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention is illustrated in the following drawings in which:
FIG. 1 is a schematic representation of the liquid mixing system; and,
FIGS. 2A-C is an electrical schematic of the circuitry for the sequence control means operating the liquid mixing system of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 there is shown liquid mixing system 10 which facilitates the mixing and continuous discharge of spray dampening fluids for use in an offset printing process. The invention will be appreciated as having application to numerous other types of industrial processes requiring mixing and supplying a continuous flow of liquids.
System 10 is characterized by the stacking of a batch mixer 12 over a feed tank 68 which are in fluid communication by means of an intermediate valve 64. Sequence control means 14 electrically controls operation of the system upon closing a power switch along power line 16, which is initiated by the printing process (not shown). Control means 14 comprises electrical sequence circuitry and connecting wiring as will be explained hereinafter with regard to FIGS. 2A-C.
Etch, ie., a wetting solution concentrate, is fed into mixing vessel 90 of batch mixer 12 via a pressurized feed line 38 to be mixed with water entering through feed line 24. Means for effecting transfer of the mixed liquids from the batch mixer to the feed tank, and for discharge from the feed tank, includes a source of pressurized air entering through air supply line 54. A normally closed valve 20, which fluidly communicates with water feed line 24 and etch feed line 38, controls water-etch admittance to mixing vessel 90. Normally closed water valve 22 operates in response to liquid level sensors, or limit probes, associating interiorly of mixing vessel 90, which regulate the volume of water per cycle. Etch supply valve 36 operates responsively to a signal generated by a conductivity probe 46 and associated meter 48 to supply etch to vessel 90.
After mixing cycles, a three-way air valve 50, along air line 54, is opened to pressurize mixing vessel 90. Intermediate valve 64 is then opened and the liquid is forcefully evacuated into feed tank 68. A by-pass valve 42 is simulataneously opened to equilibrate pressures between vessel 90 and feed tank 68. If feed tank 68 is already pressurized, displaced air will move upwardly to vessel 90 through by-pass line 40 as fluid enters tank 68. Pressurization of vessel 90 terminates when the liquid level drops below low level L 1 at sensing means 18.
Discharge of the mixed chemicals from feed tank 68 is initially made possible by the equalized pressurization created upon opening by-pass valve 42. Pressurization is thereafter continuously maintained by a three-way air valve 74 opening response to a signal generated by low limit sensing means 72 when liquid levels are above L 3 in the feed tank L 3 . Pressurized air from line 76 is thereby introduced to the feed tank. Pressure regulator 80 opens at a minimum pre-set pressure level and serves to discharge the water-etch mix at constant pressure and flow into supply line 84. When the transfer from the batch mixer 12 has reduced the liquid level in mixing vessel 90 below sensing means 18, the sensing means signals the sequence control means and air by-pass valve 42 and intermediate valve 64 are closed. The mixing sequence repeats while the liquid in pressurized feed tank 68 is continuously discharged through regulator 80 into supply line 84 for use in a spray dampening system. Before liquid in feed tank 68 drops below level L 3 , the mixing cycle is completed and the next batch is transferred from batch mixer 12. Thereby, continuous feed, at constant pressure, is achieved.
Operation Of The System
At the beginning of operation, vessel 90 and feed tank 68 are empty and not pressurized. The sequence of operation for the system is controlled by sequence control means 14, as will be explained. Initially a demand for the mixed fluids is signaled, such as from an offset printing procedure, by closure of a power switch on power supply line 16. The sequence of operation then begins.
Upon activation, sequence control means 14 receives a vessel-empty signal from low level sensing means 18, which at or below level L 1 has closed contacts. Normally closed valve 20 is activated to open and is followed by the activation of normally closed water valve 22. Water conveyed by feed line 24 is introduced through a flared receiving pipe 26 communicating with normally closed valve 20 and enters vessel 90 of batch mixer 12 via inlet pipe 88. Normally closed water valve 22 remains open until high limit probe 28 contacts open by the water filling to level L 2 . At level L 2 , sequence control means 14 closes water valve 22 and starts mixer motor 30. Mixer motor 30 communicates internally of batch mixer 12 by means of a shaft 32 having mixing blades 34 inside vessel 90. When the mixer motor starts, the probe 46 senses solution conductivity below a value pre-set at meter 48. Responsively, etch supply valve 36 is opened to allow etch to flow from feed line 38 into vessel 90 through opened valve 20. Feed line 38 communicates with a constant supply of etch, such as may be provided by a remote automatic pumping unit and etch reservoirs, whereby line 38 is pressurized and ready to supply valve 36. Conductivity probe 46, which communicates with the interior of mixing vessel 90, senses the increasing conductivity of the solution. Upon reaching the desired conductivity set at conductivity meter 48, the etch valve 36 open sequence ends. As the mixer motor continues to stir the solution, conductivity may drop below the desired level. In that case, the drop is sensed by probe 46, and etch supply valve 36 is signalled to open and supply additional etch to the mixer until the proper value stabilizes.
When the mixed solution reaches the stabile level of conductivity for about five to six seconds, valve 36 and valve 20 are both closed, and mixer motor 30 is de-energized. Mixing vessel 90 is then fully charged with the mixed liquid. Three-way air valve 50 along air supply line 54 is activated to open. An on-off valve 52 is manually operable and is preferably opened before beginning operation of the system in order to pressurize air supply line 54. A pressure regulator 56, disposed along line 54, maintains a pre-set constant pressure for introduction to the system. The regulated pressure in air supply line 54 is preferably maintained in the range of about 80-100 pounds per square inch. A T-pipe coupler 58 is provided to permit flow in two directions. At this stage of the operation, the pressurized flow is directed only through three-way air valve 50 into air line 60. An air line coupler 62 communicates to the interior of mixing vessel 90 and connects with air line 60 for admission of pressurized air into vessel 90 upon opening valve 50.
After a timed sequence of pressurization, intermediate valve 64, which is closed during mixing, is signaled to open and the mixed liquids transfer under pressure from batch mixer 12 via outlet pipe 66, through valve 64, into feed tank 68 via inlet pipe 70. If the liquid level in feed tank 68 is below level L 3 , such as when system 10 is first started, it will not be pressurized when intermediate valve 64 is opened. Therefore, an air by-pass line 40 is provided and connects vessel 90 to feed tank 68 at air couplers 44a, 44b, respectively. A normally closed by-pass valve 42, disposed along line 40, is opened as intermediate valve 64 opens. The pressure between vessel 90 and feed tank 68 is thereby equalized and system 10 is immediately ready to supply a pressurized flow of dampening solution through feed tank regulator 80 into supply line 84.
Feed tank 68 includes low limit sensing means 72, which contacts open when the transferring fluids reach level L 3 . Sequence control means 14 then activates three-way air valve 74 to open. Pressurized air from supply line 54 then also follows the second direction through T-pipe coupler 58, and passes through three-way air valve 74 into air line 76. Air line 76 communicates internally of feed tank 68 by means of air line coupler 78. Feed tank 68 is pressurized by air line 76 until fluid levels drop below L 3 at the termination of operation. Pressure regulator 80 communicates with the bottom of feed tank 68 at outlet pipe 82. Regulator 80 is of a conventional design and is set to open when pressures in the feed tank reach a pre-determined amount, generally at or slightly below the pressure in line 54. This value is reached initially when by-pass valve 42 opens and is maintained during operation by pressurization from feed line 76. The mixed water and etch are discharged under constant regulated pressure into supply line 84 and then to the spray dampening system. Feed tank 68 may also have conventional cooling coils 86 spaced therearound, as shown.
The continuous discharge from feed tank 68 is achieved by means of low level sensing means 18 inside vessel 90. When the transfer from batch mixer 12 causes the liquid level to drop below level L 1 , sensing means 18 contacts close. At this point sequence control means 14 responsively closes intermediate valve 64, while at the same time feed tank 68 remains pressurized and continues discharging the previous batch into supply line 84. At the closure of intermediate valve 64, three-way air valve 50 is simultaneously activated and reverses to an exhaust position for a pre-set duration to de-pressurize of mixing vessel 90. The "empty" signal from low level sensing means 18 is the start of the next mixing cycle. After the timed sequence, air valve 50 returns to the closed position, valve 20 is again signaled to move to the open position, normally closed water valve 22 is again signalled to open, and the mix and transfer cycle repeats as explained above.
The illustrative embodiment shown in FIG. 1 uses pressurization as the means for transferring and discharging the mixed liquids. Alternatively, the use of pumps is envisioned. An electric pump, for example, could be provided between outlet pipe 66 and feed tank inlet pipe 70. The air supply means and pressurization steps would be eliminated. Intermediate valve 64 would then be eliminated and instead the pump would be signalled to start pumping when mixing ended. An electric pump for feed tank 68 could also be provided to associate with outlet pipe 82. Pressure regulator 80 would also be eliminated, and the constant pressure flow into supply line 84 would be maintained by the pump. In this alternate embodiment the steps of activating three-way air valves 50 and 74 and by-pass valve 42, would be replaced by activation of the electric pumps at the necessary times during the transfer and discharge sequences, as explained hereinbefore.
The Sequence Control Means
System 10 is sequentially operated by control means 14 having the circuitry as shown in FIGS. 2A-C, which comprises a single circuit, as will be understood. During operation, the activation, or energizing, of the various components of system 10 is indicated by control panel lights, so that the operator may monitor the system. The circled symbols referenced R-1, R-2, etc. are relays and TD-1, TD-2, etc., are time delay relays. The uncircled references R-1, R-2, TD-1, TD-2, etc., represent the respective normally closed or normally open contacts of the various R and TD relays. Notations on the Figure are provided to aid in following the sequence of operation of the mechanical components of system 10.
Initiating Operation
The circuitry is provided with power line 16 and ground 16'. A power switch 92 for power line 16 is closed when dampening solution is required. The power switch may be automatically closed in response to control circuitry of a spray dampening apparatus, as would be understood by one skilled in the art. When power switch 92 contacts close, the intermediate valve 64 closed solenoid is energized assuring that the intermediate valve 64 is closed at the beginning of operation. When starting operation, with mixing vessel 90 and feed tank 68 empty, relays R-1, R-2, and R-3 will all be energized by the closed upper and lower float switches 46, 18, respectively, in the upper tank, and closed low limit float switch 72 in the feed tank. The low limit 72 override switch is closed.
Relay R-4 will be energized as a result of relay R-1 contacts being closed, and relay R-8 will be energized through the intermediate valve 64 closed microswitch. Time delay relay TD-1 begins a six to eight second time delay "on" as a result of R-4 and R-8 contact closure, which also energizes the exhaust valve 50 solenoid and corresponding exhaust light.
The mixer means 12 is now prepared to begin a fill sequence. The feed tank 68 low limit light is on as a result of R-3 contact closure. The intermediate valve 64 closed light is on inasmuch as it is parallel to R-8 in the circuit. The mixer means 12 low limit light is on as a result of R-2 contact closure. At this point, valve 20 may be opened or closed, since either way, the circuit is unaffected. All other relays, timers, lights, and valves are off.
At the completion of the 6 to 8 second timing period of time delay TD-1, the fill sequence initiates.
The Fill Sequence
Step 1. Time delay relay TD-1 is energized when its timing period is complete.
Step 2. As a result of TD-1 contact closure, relay R-10 is energized.
Step 3. The valve 20 open solenoid is energized as a result of R-10 contact closure.
Step 4. Relay R-7 is energized by the valve 20 open microswitch contact closure.
Step 5. Water valve 22 solenoid is energized, and the water light is turned on as a result of R-7 contact closure. The mixing vessel 90 now begins to fill with water flowing through line 24.
Step 6. As the water level in vessel 90 rises above lower probe 18 at level L 1 , relay R-2 is de-energized and the low limit light is turned off.
Step 7. When the water level in vessel 90 reaches high limit probe 46 at level L 2 , relay R-1 is de-energized. As a result, the high limit light is turned on through a normally closed set of R-1 contacts. Meanwhile, R-4 is de-energized as R-1 contacts open.
Step 8. The valve 20 solenoid, water light, valve 22 solenoid, exhaust valve 50, time delay TD-1, and exhaust light are all de-energized as R-4 contacts open. Time delay relay TD-2 begins a 1.2 second time delay "on". Vessel 90 is now filled with the appropriate amount of water and is ready for mixing with the etch.
The Mixing Sequence
Step 9. At the completion of the 1.2 second timing period of TD-2, time delay relay TD-2 is energized.
Step 10. As a result of TD-2 contact closure, relay R-11 is energized.
Step 11. As a result of R-11 contact closure, mixer motor 30 is activated and begins to stir the fluid in vessel 90. The mixing light simultaneously is turned on. Also simultaneously, the etch light, etch valve 36, and relay R-9 are energized through closed conductivity meter 48 and R-7 contacts. Conductivity meter 48 relay is energized when conductivity, sensed at probe 46, is below a pre-set value. It de-energizes when the conductivity of the solution in vessel 90 exceeds this pre-set level.
Step 12. Since supply line 38 is associated with a pressurized source of etch, or an on-demand automatic pumping system, when valve 36 opens, etch flows into the vessel 90 through valve 20 and is blended with the water by the action of the blades 34 of the motor. The conductivity of the solution is increased.
Step 13. When the conductivity of the solution exceeds the pre-set value, the conductivity meter 48 relay de-energizes. Subsequently, the etch light, etch valve 36 and relay R-9 are de-energized as the meter relay 48 contacts open.
Step 14. Normally closed meter 48 relay contacts turn on the conductivity light and start the timing cycle of time delay relay TD-4. The motor 30 is still stirring the solution to ensure thorough mixing, and should conductivity drop below the pre-set value, etch valve 36 will be re-energized to add more etch and stabilize the mixed solution at the pre-determined level. When the mixed solution reaches a stable level of conductivity for about five to six seconds, TD-4 will complete its timing cycle and be energized. Transfer of the mixed water/etch solution is now ready to be made to feed tank 68.
The Transfer Sequence
Step 15. As a result of TD-4 contact closure, relay R-5 is energized. Valve 20 closed solenoid is also energized. Time delay TD-2 contacts are already closed.
Step 16. When R-5 energizes, normally closed contacts open to turn motor 30 and motor light off. Another set of R-5 contacts close to start the timing cycle of time delay relay TD-5.
Step 17. Relay R-6 energizes when the valve 20 closed microswitch closes and the valve 20 closed light turns on.
Step 18. The batch mixer air pressure valve 50 and air pressure light are energized. The mixing vessel 90 is then pressurized by air entering through feedline 60.
Step 19. Upon completion of the TD-5 timing cycle, about 1.2 seconds, TD-5 is energized.
Step 20. As the result of TD-5 contact, intermediate valve 64 open solenoid, by-pass valve 42 solenoid and by-pass valve light are energized. If feed tank 68 is empty, i.e., fluid level below level L 3 and float switch 72 contacts closed, it will not be pressurized due to relay R-3 normally closed contacts being open. In this case, the mixed solution will descend through intermediate valve 64 to fill the feed tank 68 and pressurized air will flow through by-pass valve 42 along line 40 to equalize the pressure between vessel 90 and feed tank 68. Thus, as intermediate valve 64 opens, mixing system 10 is ready to supply a pressurized mixed solution from feed tank 68 to a spray dampening system. If the feed tank 68 already has fluid above level L 3 , and the low limit override switch is closed, as is the case during continuous operation, tank 68 will already be pressurized when the by-pass valve 42 and intermediate valve 64 open. Where feed tank 68 is already pressurized, the mixed solution will transfer via intermediate valve 64 and air displaced from feed tank 68 will flow up through valve 42 along line 40 into vessel 90.
Step 21. When the fluid level in vessel 90 drops to level L 1 , relay R-2 is energized.
Step 22. As a result of R-2 contact closure, relay R-1 is energized. Another set of R-2 contacts open to de-energize time delay TD-2.
Step 23. Time delay TD-2 contacts then open to de-energize R-11.
Step 24. As a result of R-1 contact closure and R-11 normally closed contacts, R-4 is energized.
Step 25. Normally closed R-4 contacts open to de-energize time delay TD-4.
Step 25. TD-4 contacts open to de-energize TD-5, mixing tank 90 air pressure light, mixing tank air pressure valve 50, intermediate valve 64 open solenoid, by-pass valve 42 and the by-pass light.
Step 26. Normally closed TD-5 contacts energize the intermediate valve 64 closed solenoid.
Step 27. The intermediate valve 64 closed microswitch closes to energize the intermediate valve 64 closed light and R-8.
Step 28. As a result of R-4 and R-8 contact closure, time delay TD-1 begins its timing cycle.
Continuous Discharge
Following Step 28, the sequence is repeated beginning with Step 1. Inasmuch as the level in the feed tank 68 is above L 3 during continuous operation, feed tank lower limit switch 72 contacts will be open and the relay R-3 normally closed contacts will be closed to thereby open the feed tank air pressure valve 74, energize the associated air pressure light, and maintain pressurization of feed tank 68. Pressure regulator 80 is set to open and regulate outflow when pressure inside feed tank 68 reaches a pre-determined level, preferably set at or below the line 54 air pressure value. The mixed water-etch solution is discharged into line 84 for delivery to a spray dampening system continuously during repetitive sequences of system 10.
The Etch Supply
During mixing sequences, when etch valve 36 is energized, pressurized etch from a remote automatic pumping unit is fed to the mixing vessel 90. In the event that a remote pumping unit is not employed, a drum switch control may be provided with the mixer. The drum switching control would pump etch from one of a plurality of etch reservoirs and automatically switch to a full reservoir when a previous reservoir becomes empty. A signal to the drum switch control can be provided, as shown in FIGS. 2B, C, whenever the etch valve is energized. An etch demand relay may be provided in the drum switch control, which is energized whenever mixer 30 and etch value 36 are energized, on demand, to provide contact closure and send a signal to a pumping control circuit to activate a pump and siphon etch from a reservoir. Should a reservoir become empty, no etch will arrive through line 38 and the pre-set conductivity level at meter 48 will not be reached. Time delay relay TD-3 begins its timing cycle every time etch is demanded. When etch is supplied, the conductivity level is satisfied before the timing cycle is completed and the timing circuit is disabled in normal mixing operation. However, if the conductivity is not at the pre-set level after a pre-set period of about one hundred seconds, TD-3 is energized and contact closures provide a signal, as will be understood with respect to the schematic shown on FIG. 2C, to the drum switch control. The drum switch control may include means to determine and select a reservoir which is full, whereby an associated pump siphons etch to valve 36 along line 38 for admission to mixing vessel 90. The mixing sequence then continues. Upon satisfying the level of conductivity desired, and reaching stabilization for five to six seconds, time delay TD-4 will complete its timing cycle following the de-energizing of etch valve 36 and relay R-9, which are responsive to meter 48 contacts opening.
ACHIEVEMENTS OF THE INVENTION
A liquid mixing system is provided which maintains a continuous flow of a mixed water-etch solution at constant pressure for use in a spray dampening system. While the embodiment disclosed is directed toward use for spray dampening rollers in an offset printing process, it will be understood that invention has use in other industrial applications, wherein mixed fluids are required to be supplied at a constant rate of flow. The system maintains constant pressurization of a feed tank which continuously discharges to a supply line during repetitive mixing sequences in the batch mixer means stacked thereabove. The batch mixer alternately mixes and transfers mixed solution to the feed tank, until demand is satisfied. The liquid mixing system fill, mix, transfer, and discharge sequences are controlled by sequence control means electrically communicating with valves and mixer means in response to liquid levels in the system and to the conductivity of the water/etch solution. A wide range of sequence control means are envisioned.
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A liquid mixing system is disclosed which provides a continuous and constant pressure flow rate during operation, having particular use in spray dampening operations for offset printing procedures. The mixing system includes a stacked arrangement of a batch mixer and feed tank fluidly communicating therebetween, and transfer means sequentially activated to transfer the liquids to the feed tank upon completion of mixing the liquids. The feed tank having means for discharging liquids therefrom at a constant flow and pressure. Control means sequentially operate the system for the admission and mixing of liquids in predetermined amounts to the batch mixer, for transferring the mixed liquids from the mixer to the feed tank, and for discharging the mixed liquids from the feed tank. The system is capable of repetitive mixing and transfer cycles while continuously discharging from the feed tank at a constant flow rate.
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BACKGROUND OF THE INVENTION
The invention is generally concerned with the automatic control of injection molding machines. More specifically, this invention relates to a control for an injection molding machine in which a work-indicative parameter is integrated with respect to time during the injection of plasticized material into a mold thus defining a work index which is used to control the molding machine.
In the past it has been common to employ monitoring systems and controls in injection molding apparatus. Typically, a monitor comprises apparatus for recording specified variables during each cycle of the injection molding apparatus. Such monitoring systems, however, require manual changes to be made by an operator to obtain consistently uniform products. Ordinarily, the operator reviews the recorded variables for consecutive molding cycles and then makes an appropriate adjustment to the injection molding apparatus such that acceptable products are likely to be obtained.
Control systems comprise another type of automatic control for injection molding machines. Typically, control systems sense one or more parameters which are considered to be necessarily associated with the injection molding of uniform, high quality products. Each of the sensed parameters is compared with a specified range within which the parameter must lie in order to give acceptable products. If a sensed parameter lies outside of its allowable range, a feedback system is ordinarily provided to make a compensating adjustment to an operating parameter of the injection molding machine.
With monitoring systems and their reliance on human operators, there is a substantial likelihood that a large number of non-uniform, or low quality products may be molded before the injection molding apparatus can be brought within acceptable limits. It is noted in passing that unacceptable products generate excessive manufacturing costs and waste costly plastic materials.
Control systems, by comparison, substantially reduce the number of unacceptable products by automatically making compensatory adjustments when necessary. As noted above, control systems typically sense particular parameters and maintain those parameters within specified limits. While some such controls are useful, there has persisted a need for a truly practical one capable of maintaining product quality even in the face of variations in feed stock and ambient conditions. Feed stock of synthetic resinous material varies from one batch to another and frequently contains varying proportions of virgin and reground material. Both of those characteristics may adversely affect product quality. Ambient temperature is still another variable which can affect the operation of injection molding apparatus and product quality. The above are but a few of the variables which can affect the molded parts and the minimum range which may be specified for the sensed parameters.
Aside from the variables which affect the minimum range for the sensed parameters, there remains the problem of which parameter or parameters are to be sensed as being the most representative of a quality product. A myriad of such parameters have been proposed for use heretofore, including many of the operating parameters of the injection molding apparatus such as injection ram velocity, melt temperature, melt pressure, hydraulic injection pressure, injection time interval, mold pressure, etc.
Some molding process controls have employed sensing devices to indicate when a mold cavity is filled to a specified pressure. Such sensing devices have been used to shift molding apparatus from an injection portion to a holding portion of the molding cycle. In addition such sensing devices have been used as an indication of product quality.
It has also been proposed to indicate product quality by an integral of work-parameter integrated with respect to time between positions at the beginning and the end of a ram stroke. Typically, the selected positions have been indicated by using a linear position potentiometer. This integral has been fraught with difficulty, however, since the end or bottom of a ram stroke is variable from cycle to cycle. Accordingly, a physically fixed position for the end of the stroke may allow significant product quality variations between consecutive mold cycles.
The use of mold pressure sensors alone has, likewise, been problematic. More specifically, there may be a sink region in the mold or an excessively packed region. In addition, other parameters of the molding apparatus may manifest quality-affecting excursions which are not reflected in the selection of mold pressure.
It is therefore apparent that these previously used parameters have not been altogether satisfactory for controlling injection molding apparatus.
BRIEF SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a novel injection molding process control which derives an index correlatable with product quality over a range of variations of conditions and uses this index to regulate the operation of an injection molding machine.
In accordance with a preferred embodiment of the present invention, hydraulic injection pressure, which translates a plasticizing screw to inject a quantity of molten material into a mold, is integrated with respect to time during the injection portion of each molding cycle and until a predetermined pressure is attained by molten material accumulating in the mold cavity. This integration yields a work index which is indicative of the work required to inject the molten material throughout the injection portion of the cycle and thereby represents the net effect of all viscosity perturbations during injection. In addition the integration automatically responds to variations of material properties, to machine or mold variations and to ambient conditions, all of which may affect sequential molding cycles. The integration limits used here also obviate the effect of vagaries in the physical length of each injection stroke and the precise physical position where the injection stroke ends by eliminating reliance thereon.
The integration preferably ends simultaneously with the occurrence of a selected mold cavity pressure such that the combination of the work index and the selected mold cavity pressure assure the repetitive molding of consistently uniform products. By placing a mold cavity sensor at an extremity of the cavity, the sensor is also effective to indicate that the mold has been filled which is also a requirement for consistent product quality.
Having obtained an index of the work expended, the index is compared with an adjustable pre-set allowable range therefor. This comparison permits a continuous evaluation of injection apparatus performance during consecutive molding cycles while also making possible a record of molding machine operation. In the event that the index does not fall within the allowable range, the comparison may be used to generate a signal to adjust an appropriate parameter of the molding machine.
When the index for a particular cycle does not lie within the allowable range, a compensating adjustment is made to a viscosity-affecting parameter such as hydraulic back pressure exerted on the plasticizing screw during the plasticizing portions of a cycle. The adjustment is made for subsequent cycles and thus compensates for all viscosity perturbations of the previous cycle. Moreover, this adjustment procedure accommodates gradual changes in slowly changing variables such as ambient temperature in addition to relatively rapid fluctuations which may result from changes in material composition.
Another feature that may be incorporated into the process control of the present invention provides a predetermined number of molding cycles within which the index is permitted to seek a value within the allowable range. If the index does not adjust itself within the number of cycles, an appropriate indication may be made to signal that the machine is out of control. This feature may be particularly advantageous in applications where a single operator is charged with simultaneously monitoring several molding machines.
With some work-affecting parameters, it may be advantageous to delay corrective changes so that spurious changes are not made in response to occasional erratic calculations of the work index. Accordingly, the present invention may also be provided with a delay circuit which postpones any change until a selected number of consecutive cycles require change.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features of the present invention will be apparent to those skilled in the art when the appended claims are read in light of the following description and the drawings in which:
FIG. 1 is a diagrammatic view, in partial cross section, of an injection molding machine connected to a process control according to the present invention; and
FIG. 2 is a diagrammatic illustration of the control system.
DETAILED DESCRIPTION OF THE INVENTION
Depicted in FIG. 1 is a cyclically operated injection molding apparatus comprising plasticizing apparatus 10, a suitable mold and a process control 50. The plasticizing apparatus 10 includes a hopper 12 which receives particulate synthetic resinous material for delivery to a reciprocable rotary screw 16 that is mounted internally of a barrel 18 wherein the material is plasticized and pressurized. Wrapped around the external circumference of the barrel 18 are a plurality of band heating elements 20, 22, 24. At the outlet end of the barrel 18, a nozzle section is provided which includes an external band heating element 26.
The nozzle section of the barrel 18 communicates with a mold comprising a stationary mold portion 28 and a movable mold portion 30. The stationary mold portion 28 and the movable mold portion 30 cooperate to define a mold cavity therebetween into which plasticized material is injected from the plasticizing apparatus 10 such that a molded article or product results.
At the end of the screw 16 opposite from the mold, suitable apparatus is provided to both rotate and reciprocate the screw 16 relative to the barrel 18. More specifically, a screw drive motor 32 is provided to impart rotary motion to the screw 16 during a plasticization portion of a molding cycle. In addition, the screw 16 is provided with a piston end 34 which is mounted internally of a cylinder member 36 such that a chamber 38 is defined therebetween. The chamber 38 is supplied with pressurized hydraulic fluid from a reservoir 41 through a suitable pump 40.
The pump 40 provides a high pressure high volume flow of hydraulic fluid to the chamber 38 to reciprocate the screw 16 during an injection portion of the molding cycle, and supplies a low volume low pressure flow of hydraulic fluid to the chamber 38 during a holding portion of the molding cycle. Communicating with the chamber 38 and a reservoir 41 is a suitable back pressure control 42 which provides a variable adjustment of the back pressure acting in the chamber 38. The back pressure control 42 may comprise a conventional electric relief valve.
To control the flow of hydraulic fluid from the pump 40 to the chamber 38, a control valve 46 is preferably provided. The valve 46 may comprise a conventional electric control valve and is operable to control both the volume and pressure of hydraulic fluid in chamber 38.
As illustrated in FIG. 1, a second pump 43 may be provided to supply hydraulic fluid to the hydraulic motor 32 which rotates the screw 16. A suitable screw speed control 44 is provided between the pump 43 and the hydraulic motor 32 for regulating the speed thereof. The screw speed control 44 may be a conventional electric flow control valve.
The mold cavity between mold portions 28, 30 is provided with a suitable sensing means 48 which is preferably disposed at an extremity of the mold cavity remote from the plasticizing apparatus 10. The mold cavity pressure sensor 48 measures the pressure of plasticized material which has been injected into the mold. Moreover, by positioning the sensor 48 at an extremity, the sensor 48 ensures that the sensed pressure represents the pressure in a filled mold cavity. The pressure sensing means 48 is operable to generate a signal representing plasticized material pressure and to communicate this material pressure signal to the process control apparatus 50.
The chamber 38 includes an injection pressure sensing means 52 which generates a signal that is indicative of the hydraulic pressure in the chamber 38. This injection pressure signal from the pressure sensing means 52 is also input into the process control apparatus 50. The reciprocating screw 16 may also be provided with an integration-initiating position transducer 54 which indicates the position of the screw 16 with respect to the barrel 18. The linear position transducer 54 provides an input signal for the process control apparatus 50.
Turning now to FIG. 2, the process control apparatus 50 includes a settable selected mold cavity pressure input 60 that establishes a predetermined pressure which is to be attained by plasticized material within the mold cavity. A predetermined allowable range for a work index is input to the process control apparatus 50 by setting a high limit 62 and a low limit 63.
An out-of-control input 64 enters a predetermined number of consecutive molding cycles within which the control apparatus 50 is expected to bring the work index calculated for each cycle within the range specified by the limits 62, 63. In the event that the control apparatus 50 fails to bring the work index within the specified allowable range within the predetermined number of cycles, a suitable alarm means 108 may be provided to summon assistance from an operator.
An increment size adjustment 66 specifies the magnitude of an incremental change which is to be made in a viscosity-affecting parameter for subsequent molding cycles in the event that the work index does not lie within the specified allowable range therefor. Preferably, increment size adjustment 66 specifies a percentage change which is to be made.
The process control apparatus 50 may also include a selectively operable time delay circuit having a timer with a variable adjustment 67. The time delay circuit may be used to postpone incremental changes in a viscosity-affecting parameter when desired.
In operation, the injection molding cycle may be considered in three portions: a plasticizing portion, an injection portion and a holding portion. During the plasticizing portion, particulate material (see FIG. 1) is introduced through the hopper 12 to the screw 16. The screw compacts, compresses, heats and plasticizes the particulate, synthetic resinous material while it is conveyed forwardly along the length of the screw 16. The band heaters 20, 22, 24 around the barrel 18 may transfer additional heat to the plasticized material and facilitate the plasticization thereof.
As the plasticized material accumulates at the left end of the screw 16 as seen from FIG. 1, the plasticized material develops a fluid pressure acting upon the end of the screw, which tends to translate or reciprocate the plasticizing screw 16 to the right. To resist the tendency of the plasticizing screw 16 to translate in response to the accumulating plasticizing material, hydraulic back pressure is exerted on the piston end 34 from the chamber 38. By controlling the back pressure in the chamber 38, the pressure in the plasticized material accumulated in the screw and the barrel 18 may be controlled.
The back pressure acting on the screw 16 is conventionally known to have a significant effect on the amount of work required during injection, and on the viscosity of the plasticized material accumulated between the screw 16 and the barrel 18. Accordingly, the back pressure exerted on the plasticizing screw 16 is a viscosity-affecting parameter of the plasticizing apparatus 10 which has a potent effect on the viscosity of the material plasticized therein.
When a sufficient volume of plasticized material, or "shot", has been accumulated in the plasticizing apparatus 10, the injection portion of the molding cycle may commence. A high volume high pressure flow of hydraulic fluid from pump 40 is introduced into the chamber 38. The plasticizing screw 16 is then translated to the left (see FIG. 1) with respect to the barrel 18 thereby discharging or expressing the shot of plasticized material which had been accumulating therein. The shot is thus injected into the mold cavity defined between the stationary mold portion 28 and the movable mold portion 30 to form the molded article.
The transition between the plasticizing portion of the cycle and the injection portion of the cycle may be indicated by using a preselected positon of the integration-initiating position transducer 54. The preselected positon may be adjustable such that material in gates of the mold is cleared before the preselected position is reached by the position transducer 54.
Typically, the injection portion continues until the mold cavity is filled with plasticized material and until the plasticized material in the mold attains a specified pressure. With the present invention, the end of the injection period is signaled when the mold cavity sensor 48 attains the predetermined value input at 60.
While the material in the mold is solidifying, a suitable holding pressure must be maintained, to accommodate for material shrinkage in the mold which frequently occurs, if uniform, high quality articles are to be molded consistently. Accordingly, the third portion of the molding cycle, the holding portion begins when the mold pressure has attained the selected value. During the holding portion, a low volume low pressure flow of hydraulic fluid is maintained in the chamber 38. The change in flow volume and pressure between the injection portion and the holding portion may be triggered by the mold cavity pressure sensor 48.
The holding portion of the molding cycle continues until the plasticized material injected into the mold has solidified sufficiently for an article to be removed from the mold. Thereupon, the plasticizing portion of the cycle is initiated and continues as discussed above. During the plasticizing portion, the movable mold portion 30 may be withdrawn from association with the stationary mold portion 28 such that the article can be removed therefrom. The mold cavity portions 28, 30 then return to their abutting relationships such that the mold cavity is closed and is ready to receive the next shot of plasticized material from the plasticizing apparatus 10.
Turning now to FIG. 2, the operation of the process control apparatus 50 may be more readily visualized. The pressure sensing means 52 senses hydraulic injection pressure in the chamber 38 and provides a pressure-related input signal to an integrator 68 which may comprise an operational amplifier 67 having a capacitive feedback network 69. The integrator 68 integrates the injection pressure signal with respect to time and preferably begins at the inception of the injection portion of the cycle.
An initiator 70, which operates in response to the integration-initiating position transducer 54, may be used to signal the integrator 68 to begin. Typically the initiator may comprise an enabling circuit 71 such as a switch connected in parallel with the integrator 68. As the plasticizing screw 16 of FIG. 1 begins an injection stroke in response to an increased injection pressure in the chamber 38, the position transducer 54 will encounter the preselected position and then signal the integrator 68 through the initiator 70 (FIG. 2) to commence the integration of injection pressure with respect to time.
The integration of injection pressure preferably continues throughout the injection portion of the molding cycle until a stop signal is communicated to the integrator 68 from a comparator 72. The comparator 72 compares the pressure set by input 60 with a signal communicated to an analog comparator circuit 73 by the mold cavity material pressure sensing means 48.
When the mold cavity pressure attains the predetermined value, an enabling circuit 74 is inhibited by a binary signal from the comparator circuit 73 to stop the integration process. Simultaneously, the comparator circuit 73 signals the valve 46 to shift to its low pressure low volume flow position.
The output 76 of the integrator 68 constitutes an index of work performed on the plasticized material in the shot during the injection thereof into the mold and until the mold is filled with plasticized material to a predetermined pressure. More specifically, the time integral of hydraulic pressure acting on the piston end 34 of the plasticizing screw 16 (see FIG. 1) during the time a shot of material is injected into the mold is a measure of the work required to overcome the flow resistance of the plasticized material and to inject the shot into the mold. It is noted that viscosity is a measure of the resistance of a fluid to internal flow and the work required to inject the shot into the mold therefore may represent the apparent viscosity of the material injected. By integrating the work required to inject a shot into the mold throughout the entire injection portion of the molding cycle, any perturbations affecting the injection stroke or the viscous fluid flowing into the mold cavity are accounted for. Moreover, by continuing the integration until a specified pressure is developed in the material injected into the mold cavity, a full mold with uniformly compacted material is ensured. As the most influential parameters on product quality have been found to be material pressure and the work required to fill the mold with material, the combination of the calculated work index and specified pressure enables the process control apparatus to consistently and effectively produce high quality molded articles. It should also be apparent that making calculations during fractional periods of the injection portion of the molding cycle may not provide an index as reliable as the index used here.
Having calculated a work index for the injection portion of the molding cycle, the index is evaluated by comparator logic 78 (see FIG. 2) to determine whether or not it lies in the predetermined allowable range which is input to the process control apparatus 50 through the limits 62, 63. If the work index lies within the specified range, the injection molding apparatus is operating within allowable constraints and no control adjustments are required. On the other hand, if the work index lies outside of the allowable range, a command signal is generated by the comparator 78 to change a viscosity-affecting parameter through suitable feedback means.
The comparator logic 78 includes a suitable conventional analog to digital converter 80 which preferably converts the integrator output 76 into a binary coded decimal (BCD) signal. The BCD signal is then compared with the input high and low limits 62, 63 in a suitable conventional digital comparator 82 having a high output signal 81 and a low output signal 83. The digital comparator 82 generates a high or binary one signal in the high output 81 if the calculated work index 76 is greater than the high limit 62. Similarly, the digital comparator 82 generates a high or binary one signal in the low output 83 if the calculated work index exceeds the low limit 63.
A series of three suitable gates and inverting circuits are provided in the comparator logic 78 to determine whether the work index 76 is above, within, or below the predetermined allowable range set by the input limits 62, 63. For example, a first AND gate 84 passes a command signal when both output signals 81, 83 are binary one and thus indicates that the index is above the allowable range. A second AND gate 86 passes a signal when the work index 76 exceeds the low limit 63 but does not exceed the high limit 62 and thus indicates the index is within the predetermined allowable range. The third AND gate 88 passes a command signal when both output signals 81, 83 are binary zero and therefore indicates that the calculated work index is below the allowable range.
The command signals from the first and third AND gates 84, 88 are electrically communicated to a pair of enabling circuits 90, 92 which also receive a signal from the increment size adjustment 66. The enabling circuit 90 passes a command expected to increase a viscosity-affecting parameter of the plasticizing apparatus in response to the command signal from the third AND gate 88. The enabling circuit 92 passes a command signal expected to decrease a viscosity-affecting parameter in response to the command signal from the first AND gate 84. For example, the enabling circuits 90, 92 may each comprise a suitable amplifier inhibited by a high binary signal level and enabled by a low binary signal level. The enabling circuit 90 may pass the signal from the increment size adjustment when enabled while the enabling circuit 92 may pass an inverted or negative form of this signal when enabled.
The command signal from either enabling circuit 90, 92 is communicated to one or more of the valves 42, 44, 46 through appropriate manually preset switches 94. As noted above, the valves 42, 44, 46 control the viscosity-affecting parameters of back pressure, injection pressure and screw rotation speed, respectively.
The signal from each of the three AND gates 84, 86, 88 is supplied to another comparator logic 96 which counts the number of consecutive molding cycles in which viscosity corrections occur and compares that count to the allowable number of cycles input by the input 64.
The comparator logic 96 includes two OR gates 98, 100 which receive signals from the AND gates 84, 86, 88. The first OR gate 98 is connected to the first and third AND gates 84, 88 such that it will pass a signal whenever a command signal emanates from the first comparator logic 78. The second OR gate 100 issues a shift signal for each molding cycle since it operates regardless of the value of the work index as determined by the AND gates 84, 86, 88.
To provide pulses for a conventional, resettable COUNT circuit 104, a conventional HOLD circuit 102 is connected to both OR gates 98, 100. The OR gate 98 passes a pulse which is retained by the HOLD circuit 102 whenever the work index is not within the allowable range at the end of each cycle. The OR gate 100 passes a signal for each molding cycle which instructs the HOLD circuit 102 to shift the stored pulse out and shift the new pulse, if any, in from the OR gate 98. The HOLD circuit 102 may be any suitable circuit for sampling and holding an input quantity in response to a shift signal. The COUNT circuit 104 may be any suitable binary counter having a reset input terminal R.
In the event there is no pulse stored in the HOLD circuit 102, such as when the work index is within the allowable range, then the COUNT circuit 104 is reset to zero through an inverter connected to an AND gate 101 which, in turn, is connected to the reset terminal R. The AND gate 101 also receives an input signal directly from the OR gate 100 so that the COUNT circuit 104 is reset only when there is a shift signal and no pulse stored in the HOLD circuit. When the work index lies outside the allowable range and pulses are stored during consecutive cycles, the COUNT circuit 104 accumulates the number of consecutive cycles.
A compare circuit 106 is connected to the COUNT circuit 104 and evaluates the number from the COUNT circuit 104 with respect to the allowable number of cycles input by thumbwheel 64. If the number of cycles counted exceeds the allowable preset number, a signal is sent to a suitable indicator 108 which may comprise an audible alarm that warns an operator the molding apparatus is out of control. Since the signals from the COUNT circuit and the thumbwheel 64 may be binary in nature, the compare circuit 106 may be any suitable conventional circuit for comparing two signals representing binary numbers.
The signals representing various input parameters, the computed work index and other parameters of the process control apparatus 50 may be supplied to a suitable recorder 110 which may provide a printed record 112 thereof for each molding cycle. For example, a conventional pen or chart type recorder or a recorder providing a digital record may be utilized for this purpose.
Yet another viscosity-affecting parameter which may be controlled by the process control apparatus 50 is the temperature of the barrel 18 (see FIG. 1). For this purpose a plurality of temperature sensors 114 may be provided at various locations along the barrel 18, the nozzle and on each mold portion 28, 30. The output from each of the temperature sensors 114 may be selectively scanned by a scanner 115 and then compared with a preset temperature in comparator 116 which may receive a signal from the process control apparatus 50 as illustrated at 118. The comparator 116 may be selectively activated by a switch 120 of the process control apparatus 50 (see FIG. 2) and may also provide a printed record through a second suitable recorder 122 of the type previously described (see FIG. 1). When a temperature adjustment is necessary, the comparator 116 may generate output signals to suitable solid state silicon controlled rectifiers which control the band heaters 20, 22, 24, 26 provided along the barrel 18. In this manner, the temperature of the barrel 18 may be controlled in response to the calculated work index generated in the process control apparatus 50.
Where temperature is selected as a viscosity-affecting parameter, it may be desirable to include a suitable delay circuit to inhibit temperature changes until the work indexes calculated for each of several consecutive cycles are outside the predetermined allowable range thereby confirming that an error trend exists. To enable the delay circuit, a suitable conventional switch 124 (see FIG. 2) interposed between the HOLD circuit 102 and OR gate 126 is moved to its second position. The OR gate 126 passes a signal to the COUNT circuit 104 when the switch 124 is in either its first or its second position.
With the delay circuit enabled, signals from the HOLD circuit 102 enter a suitable conventional counter-decoder 128 having a reset terminal R and an output for selecting either 3 or 4 as the number of molding cycles which are to be delayed. The counter-decoder 128 counts pulses from the HOLD circuit 102, decodes the current count, and passes a binary pulse from the output to the OR gate 126 when the selected number of consecutive cycles has been attained.
The OR gate 126 passes a pulse to the COUNT circuit 104, as noted above, and to an input of AND gate 130. A second input of the AND gate 130 receives a signal from the enabling circuits 90, 92. Accordingly, a temperature adjustment will be permitted by the AND gate 130 only when the selected number of cycles has occurred.
The counter-decoder output signal is also communicated to a time delay means which may comprise a suitable conventional timer circuit 132 having the settable input 67. The counter-decoder output signal enables the timer circuit 132 which generates an output pulse to inhibit the counter-decoder 128 for the period of time set by input 67. When the set period of time expires, the counter-decoder 128 is again operative to count consecutive cycles during which the work index is outside the allowable range. Accordingly, the time delay means allows a reaction time period before further temperature adjustments may be made.
The timer output pulse is also communicated to an input of an OR gate 134. A second input of the OR gate 134 is connected to a suitable conventional two position switch 136 which operates as a slave with the switch 124. The OR gate 134 is connected to the reset terminal R of the counter-decoder 128 such that the counter-decoder 128 is reset whenever the OR gate 134 receives an appropriate reset pulse.
The first position of switch 136 is connected to a voltage source Vo. Accordingly, the counter-decoder will always be reset at zero when the switch 124 is in its first position. When the switch 124 is moved to its second position to enable the delay circuit, the switch 136 is moved to its second position by virtue of the slave relationship. In the second position, the switch 136 receives any reset pulse emanating from the AND gate 101 for the COUNT circuit 104. Since the switch 134 is connected to the OR gate 134, the counter-decoder 128 is also reset along with the COUNT circuit 104. In addition, the counter-decoder 128 is reset when the selected number of consecutive cycles is attained by virtue of the input to the OR gate 134 from the timer circuit 132.
The process control apparatus 50, illustrated in FIG. 1, is shown separated from the plasticizing apparatus 10 in the interest of clarity. In practice it is desirable to mount the process control apparatus 50 on the plasticizing apparatus. In addition, the process control apparatus 50 may generate binary-coded decimal output signals which are directly compatible with computer storage and control.
Thus, it is apparent that there has been provided in accordance with this invention, an injection molding process control which substantially satisfies the objects set forth above. Although the present invention has been described in conjunction with a specific embodiment thereof, it is evident that many alternatives, modifications, variations and equivalents will be apparent to those skilled in the art in light of the foregoing disclosure. Accordingly, it is expressly intended that all such alternatives, modifications, variations and equivalents which fall within the spirit and scope of this invention as defined in the appended claims be embraced thereby.
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Both a method and apparatus are disclosed for controlling a cyclically operated injection molding machine such that uniform, high quality molded articles are repeatedly produced from plasticized synthetic resinous material. The method and apparatus include integration of a sensed injection pressure with respect to time from the beginning of an injection stroke until plasticized material in a mold reaches a predetermined pressure. The integration defines a work index which is compared with a preset allowable range. If the work index lies outside the preset range, an adjustment is made to the back pressure acting on the plasticizing screw during the plasticizing portion of the subsequent molding cycle. The apparatus is permitted to make a predetermined number of adjustments in the back pressure after which a suitable indication is made that the molding apparatus is out of control itself. Other viscosity-affecting parameters may be controlled including injection screw rotary speed and injection screw velocity, and barrel temperature of the plasticizing apparatus. A mold cavity pressure sensor indicates that the cavity is full, and thereupon stops the integration and may also reduce the injection pressure to a lower value, sufficient to supply additional material to compensate for shrinking due to cooling, yet not high enough to introduce strains, or cause flashing.
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FIELD OF THE INVENTION
The present invention relates to ink jet printers of the continuous type and more particularly to ink circulation constructions that eliminate the need for vacuum return of the non-used droplets that are caught by the catcher device of such printers.
BACKGROUND OF INVENTION
In continuous ink jet printing apparatus streams of uniformly spaced ink drops are created by imposing predetermined vibrations upon liquid ink filaments issuing from an orifice plate. The filaments are formed by supplying ink under pressure to a print head cavity that is iin communication with the orifice plate. Information is imparted to the droplet streams by selective non-charging or charging and deflection of droplets. A portion of the droplets pass to the recording medium but there are a substantial number of non-printing droplets that are intercepted by a catcher device and returned for recirculation. Often the print head cavity has an outlet other than the orifice plate (e.g. to facilitate dynamic pressure control within the cavity at start-up), and the apparatus ink supply system also recirculates such ink flow. In many applications a variety of other fluid couplings to the ink reservoir may be used.
For example, a common practice in continuous ink jet printers is to provide a vacuum system that is coupled to the interior of the ink supply reservoir. The reduced pressure in the reservoir is used to return ink from a print head outlet line and/or from a home station where start-up and cleaning operations can occur. Print head outlet and home station ink can be returned to the reservoir without vacuum source assist; however, heretofore a reduced pressure has been required for returning ink from the printer's droplet catcher device, so the vacuum source is also used for other return lines.
There are several disadvantages connected to the provisoin of such an ink reservioir vacuum system. For example, the air withdrawn from the ink reservoir contains an ink mist that must be collected in the ink trap (rather than vented to the atmosphere). If the ink trap does not effectively remove the ink from the air, the mist can enter the vacuum pump, dry and cause a failure or unstable operation of the vacuum pump. The ink that does collect in the ink trap is not suitable for printing and therefore is wasted. Also, as a result of such ink collection, a service call is needed to drain the ink trap.
Another disadvantage is that the negative pressure in the ink reservoir must be regulated, e.g. by a vacuum regulator. Such regulators require adjustment when the fluid system is installed. Moreover, the regulator setting must remain within an adjustment window that is determined empirically and subject to change. That is, the adjustment window is a function of the restrictions in the fluid return lines and such restrictions vary with time and can cause the vacuum regulator to be misadjusted vis-a-vis the adjustment window. In addition, the total cost of a vacuum system, which includes parts, assembly, calibration, and service constitute a considerable portion of the total fluid system cost.
U.S. Pat. No. 4,614,948 describes several continuous ink jet printer circulation systems which are aimed toward avoiding the disadvantages described above. In one described system a venturi pump is uniquely designed to utilize bypass ink flow to induce ink return from the system's catcher. In another embodiment (see FIG. 4 of '948 patent), it is suggested that caught ink can also be returned to the reservoir by coupling to a restrictor-induced line pressure drop or by gravity. Because some inks have foaming problems when subjected to low pressure inducing venturi and restrictor means, gravity return would be a most desirable alternative for obviating the above-described disadvantages of vacuum pumps.
SUMMARY OF THE INVENTION
Thus, one important object of the present invention is to provide continuous ink jet printer configurations which will simply and reliably effect gravity return of caught ink droplets from the catcher to the ink reservoir, without the use of a vacuum system. In one aspect, the present invention achieves this general object by the provision of improved printer constructions that enable such gravity return of caught ink to the ink supply reservoir. Such constructions of the present invention obtain significant advantages in simplicity, reliability and cost vis-a-vis prior art vacuum-return systems.
In one embodiment the present invention constitutes an improved ink return system for a continuous ink jet printer of the kind having a droplet generator for directing streams of ink droplets along a print path, an ink supply reservoir and means for supplying ink from the reservoir to the droplet generator. The return system includes: (i) a catcher having a catcher inlet located laterally adjacent the droplet print path for receiving non-print droplets, a catcher outlet and a discharge passage constructed and located to slope downwardly from the catcher inlet to the catcher outlet; and (ii) a return conduit that slopes continuously downwardly from the catcher outlet to the ink reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
The subsequent description of preferred embodiments refers to the attached drawings wherein:
FIG. 1 is a perspective view of one prior art continuous ink jet printer apparatus in which the present invention is useful;
FIG. 2 is a cross-sectional view showing exemplary print head structure and the prior art orientation of mounting for print head assemblies;
FIG. 3 is a schematic diagram illustrating exemplary prior art ink circulation system components of continuous ink jet printers such as shown in FIG. 1;
FIG. 4 is a side view of one preferred embodiment for print head construction, mounting and draining in accordance with the present invention;
FIG. 5 is a partial circulation system diagram that is similar to FIG. 3, but which illustrates, schematically, the improved ink return system in accord with the FIG. 4 embodiment.
FIG. 6 is a top view of the drum and catch tray structure shown in FIG. 4, with the apparatus print head removed;
FIG. 7 is a side view of the FIG. 4 catch tray as it cooperates with a lower position of the catcher outlet; and
FIG. 8 is a end view of FIG. 7.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 illustrates an exemplary prior art ink jet printer apparatus 1 of a type that can advantageously incorporate the present invention. In general, the apparatus 1 comprises a paper feed and return sector 2 from which sheets are transported into and out of operative relation on printing cylinder 3. The detail structure of the sheet handling components do not constitute a part of the present invention and need not be described further. Also illustrated generally in FIG. 1 is a print head assembly 5 which is mounted for movement on carriage assembly 6 by appropriate drive means 7. During printing operation the print head assembly is traversed across a print path in closely spaced relation to a print sheet which is rotating on cylinder 3. Ink is supplied to and returned from the print head assembly by means of flexible conduits 11 which are coupled to ink cartridge 8. A storage and start-up station 9 is constructed adjacent the left side (as viewed in FIG. 1) of the operative printing path of print head assembly 5 and the drive means 7 and carriage assembly 6 are constructed to transport the print head assembly into operative relations with station 9 at appropriate sequences of the operative cycle of apparatus 1.
FIG. 2 shows one embodiment of a print head assembly 5, used in such prior art printers. The assembly 5 includes an upper print head portion including a print head body 21 mounted on housing 22 and having an inlet 23 for receiving ink. The body 21 has a passage leading to a print head cavity 24 and an outlet 29 (see FIG. 3) leading from the cavity 24 to and ink circulation system of apparatus 1. The upper print head portion also includes an orifice plate 25 and suitable transducer means (not shown) for imparting mechanical vibration to the body 21. Such transducer can take various forms known in the art for producing periodic perturbations of the ink filament(s) issuing from the orifice plate 25 to assure break-up of the ink filuments into streams of uniformly spaced ink droplets.
The lower portion of print head assembly 5 includes a charge plate 26 constructed to impart desired charge upon ink droplets at the point of filament break-up and a drop catcher configuration 27 that is constructed and located to catch non-printing droplets (in this arrangement charged droplets). Finally, in this embodiment, the lower print head assembly includes a predeterminedly configured and located wall member 28 which provides protection and air control functions for the printer apparatus.
The ink supply and circulation system of printers such as shown in FIG. 1 typically includes various ink conduits (i.e. lines) which form an ink recirulation path. As illustrated schematically in FIG. 3, pump inlet line 71 extends from ink supply cartridge 8 to the inlet of pump 60, outlet line 72 extends between pump 60 and a main filter 69, head supply line 73 extends from main filter 69 to the print head inlet and head return line 74 extends from the print head outlet to a junction between catcher return line 75 and the main ink return line 76. An ink return line 79 also extends from station 9 back to cartridge 8. An air bleed line 78 extends from main filter 61 back to cartridge 8 and an ink bypass line 77 extends from a juncture with line 73 also back to cartridge 8. The FIG. 3 system also includes an ink heater 61, a flow restrictor 62, final filter 63, head return valve 64, temperature sensor 65 and pressure sensor 66. As will be clear from subsequent descriptions, the present invention is not limited to use with the particular ink circulation line arrangement illustrated in FIG. 3.
As shown in FIGS. 1 and 3, cartridge 8 can be in a form that is constructed to be readily inserted and removed, as a unit, from operative relation with lines of the ink circulation system. For this purpose suitable couplings 41a, 41b, 41c, 41d and 41e are formed on the cartridge 8 in a manner so as to operatively connect with lines 71, 76, 77, 78 and 79 upon insertion of the ink cartridge 8 into its mounting in the printer apparatus. In the prior art approach illustrated in FIG. 3, cartridge 8 is coupled to vacuum pump 42 to render the interior at sub-atmospheric pressure and affect ink return.
Referring now to FIG. 4, it can be seen that the print head assembly 5' in accord with the present invention is similar to the FIG. 2 print head assembly and like parts are given like numbers. However, the FIG. 4 embodiment of the present invention differs from the FIG. 2 embodiment in two important aspects. First, the print head assembly 5' is mounted on carriage assembly 6 so that the droplet stream print path P thereof is at an angle θ with respect to the vertical V, indicating the upward direction when the printer is in its normal operating orientation. Because the catcher discharge passage is formed generally normal to the droplet print path P, the discharge passage slopes downwardly from the horizontal H by approximately the same angle θ. In practice, the angle selected for θ has been found preferably to be about 15°; however, values of θ from about 5° to about 20° or more are also highly useful. In the FIG. 4 embodiment, the maximum θ value has been found to relate to preventing ink from overcoming surface tension and moving over the top of charge plate 26, in start-up modes. The minimum θ value was found to be delimited by an ink throwing defect that can occur if the gravity force for draining (i.e. slope of catcher return line) is too small. In such an instance, accelerations of the print head during traverse can sling ink out of the cater, if the θ value is too small.
In order to complete the gravity drain system in accord with the present invention, it is desirable that the return line from the catcher outlet slope continuously downwardly to the ink reservoir. This presents little difficulty in stationary head printers; however, in traversing head printers special design features are desirable. Thus, FIG. 4-8 show one construction wherein a stationary though 90 is aligned below an outlet pipe 91 from the catcher passage 92. The pipe 91 slides within the trough 90 as the catcher traverse back and forth across the print zone so that ink exiting the catcher flows into the trough continuously during traversing movement of the print head. As can be seen in FIG. 7, the bottom 94 of trough 90 slopes downwardly to a drain 95 at one end which in turn couples to the downwardly directed ink return conduit 75', so that ink from the trough will flow by gravity to the ink reservoir.
As can be best seen in FIGS. 4 and 7 the top of wall 97 of trough 90 is formed with an elastomeric seal member having a central slit 98 that extends along the length of the tray. The member forming wall 97 can therefore receive the outlet pipe 91 from the catcher drain and seal the ink within the trough from excessive evaporation.
Referring to FIG. 5, the ink supply to print head 5' is performed as described with respect to FIG. 3. However, in accord with the present invention ink is returned to reservoir 8' without the assistance of a vacuum. Thus, ink caught by catcher 28' flows via the downwardly sloping catcher passage 92 through pipe 91 and into trough 90. After flowing across the sloped bottom wall 94 of the trough to the outlet 95, ink returns to reservoir 8' via catcher return conduit 75'.
In accord with another embodiement of the invention, a flexible conduit can be coupled to the catcher outlet 91 and constrained so that it slopes continuously downwardly, from catcher outlet to the downward ink return line, during all positions of print head traverse.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
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A gravity ink return system for a continuous ink jet printer of the kind having droplet generator means for directing streams of ink droplets along a print path and ink supply means including an ink reservoir and means for supplying ink from said reservoir to said generator. The gravity return system includes a catcher having an ink return inlet located laterally adjacent the droplet print path for receiving non-print droplets deflected from said path and a discharge passage constructed and located to slope downwardly from said inlet to an outlet of the catcher. A return conduit slopes continuously downwardly from said catcher outlet to the ink reservoir.
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BACKGROUND OF THE INVENTION
A shared bus system generally includes a DATABUS, ADRBUS, and CONTROLBUS, with the operation of the system following a protocol. An address transferred on the ADRBUS selects one of several devices coupled to the bus and the transfer of data between the selected device and the bus is controlled by control signals such as R/W and a system clock.
Most shared bus systems will include a memory such as a Dynamic Random Access Memory (DRAM) to store data. In addition to transferring data to and from the DATABUS the DRAM may have other functions which limit its availability to the BUS system. Thus, the BUS system may be ready to write data to the DRAM when the DRAM is not available
As is well-known in the art, FIFOs are useful for buffering data. By using a FIFO, no data are lost if the DRAM isn't ready to receive each word when the BUS system is ready to transfer.
When data is stored in the FIFO it asserts a request signal (DRAMREQ) that is serviced by the DRAM as soon as it becomes free of other duties. If the FIFO write clock is based on the bus protocol and the FIFO read clock is based on RAM availability, then the FIFO will be read whenever one word of data is stored if the read clock is faster than the write clock. However, transferring one level of data from the FIFO to the DRAM does not take advantage of the increased transfer rate available if the page mode of the DRAM is utilized. For the transfer of a single word, the time for servicing a DRAMREQ is equal to the non-page mode access time of the DRAM and the system operates at a slow rate.
SUMMARY OF THE INVENTION
The present invention is a FIFO interface between a system bus and a DRAM that transfers data to the DRAM utilizing the high speed page mode. According to one aspect of the invention, words transferred having the same row address are accumulated in a store and then transferred to the DRAM utilizing the page mode to reduce the transfer time.
According to another aspect of the invention, the words stored in FIFO are transferred to the DRAM when the row address of a next word to be stored changes so that the page mode transfer can be utilized.
According to another aspect of the invention, data from a second page can be written to the FIFO while data from a current page is transferred to the DRAM utilizing the page mode.
According to another aspect of the invention, data from the same page can be stored without storing row addresses thereby reducing the complexity of the circuit.
Other advantages and features of the invention will become apparent in view of the following detailed description and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a preferred embodiment of the invention;
FIG. 2 is a schematic diagram of a FIFO; and
FIG. 3 is a timing diagram illustrating the operation of a preferred embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a block diagram of a preferred embodiment of the invention. The following table is a glossary of the names of signals utilized in the system:
TABLE 1______________________________________INPUT SIDE:SCLOCK: system clock.RESET: clears all registers and counters at start of operation.SAMEPAGEN: a signal that is asserted when the row address of a next word is the same as the row address of a current word.WPTRN: write pointer asserted by the state machine when a word is to be written to the data register, also called write-clock because it clocks data to the FIFO.RPTRN: read pointer asserted by the state machine when a word is to be read from the data re- gister, also called read-clock because it clocks data from the FIFO.DI: data in bus.WAD: address in bus.IBEN: inputs bus enable signal, indicates which byte on 4-byte bus is selected. Part of address.FLUSHN: asserted when all data is to be read from the data register if SAMEPAGEN is deasserted to indicate that stored data should be read before new page data is stored.OUTPUT SIDE:FULLN: indicates that FIFO is full. Asserted either when 1) SAMEPAGEN is deasserted to in- dicate that stored data should be read before new page data is stored or 2) when the WCNT catches the RCNT indicating that if more data is written it will over-write data that has not yet been read.EMPTY: indicates the FIFO is empty. Asserted when the RCNT catches the WCNT to indicate that all stored data has been read.DO: data out bus.WADO: address out bus.OBEN: byte enable out bus.DRAMREQN: asserted when the value of the WCNT exceeds the value of the RCNT by a preset value.INTERNAL SIGNALSWCNT: the count value output by the write counter. The value is incremented by WPTRN and cleared by RESET.RCNT: the count value output by the read counter. The value is incremented by RCPTRN and cleared by RESET.______________________________________
In FIG. 1 a page-in, burst-out (PIBO) FIFO 10 interfaces a SYSTEM BUS including a SYSTEM ADDRESS BUS (ADRBUS) 12 and a SYSTEM DATA BUS (DBUS) 14 and a DRAM 16. Status and control signals to be described below are transferred between the PIBO FIFO 10 and DRAM and SYSTEM BUS controllers (not shown). In FIG. 1 data paths and control and status signals input to a state machine 20 are depicted. The various control lines utilized to effect the functions described below are not depicted to simplify the diagram and because the implementation of such control functions is well-known in the art.
The PIBO FIFO 10 is designed to decrease the latency of data transfers between a system bus and DRAM by utilizing the page-mode write cycle of the DRAM. As is well-known, page mode cycles are about 3.5 times as fast as normal mode write cycles. Page mode is implemented by holding the row address strobe clock (RAS) active while cycling the column address clock (CAS). The initial cycle is a normal cycle followed by shorter CAS cycles.
A state machine 20 receives CLOCK, RESET, SAMEPAGEN, and FLUSHN signals as inputs and provides FULLN, EMPTY, and DRAMREQ signals as outputs. It also provides control signals to control the counters and registers to perform the functions described below. A write counter (WCTR) 22 has its output port coupled to a WRITECOUNTBUS 24 and it input coupled to receive a write pointer (WPTRN) signal. A read counter (RCTR) 26 has its output port coupled to a READCOUNTBUS 28 and its input port coupled to receive a read pointer (RPTRN) signal.
A data register 30 has its input data port coupled to the DBUS 14, its data output port coupled to a data input port of the DRAM, its write address port coupled to the WRITECOUNTBUS 24 and its read address port coupled to READCOUNTBUS 28. An address register 34 has its input data port coupled to the ADRBUS 12, its data output port coupled to an address port of the DRAM, its READ address port coupled to the READCOUNTBUS 28 and its WRITE address port coupled to the WRITECOUNTBUS 24. The state machine 20 has inputs coupled to the WRITECOUNTBUS 24 and READCOUNTBUS 28.
A SAMEPAGEN signal generator 40 includes a comparator 42 having a first input coupled to the address bus, a second input coupled to the output of a row address latch 44, and an output for generating the SAMEPAGEN signal.
The function of the WCNT and RCNT signals output, respectively, from the write counter 22 and read counter 26 will now be described with reference to FIG. 2. FIG. 2 symbolically depicts the data register as a circular file with WCNT pointing a slot to be filled during a write operation and RCNT pointing to a slot to be emptied during a read operation. RCNT and WCNT are incremented by the RDPTR and WPTR signals, respectively, which are derived from a system clock provided by the system bus controller and a read clock. If RCNT catches WCNT, then all slots are emptied and the state machine 20 asserts the EMPTY signal. Conversely, if WCNT catches RCNT, then all slots are filled and the state machine 20 asserts the FULL signal. If FULL were asserted and another word were written to the data register 30, then data not yet read would be overwritten and lost.
Additionally, it is apparent that if RPTRN is clocked at a rate that is faster than WPTRN, then as soon as a word is written to the slot indicated by WCNT it will be read when RCNT increments so that single words are transferred from the data register 30 to the DRAM utilizing the slow normal write cycle. Further, since data is typically transferred word by word the row and column addresses of each word stored in a FIFO must be stored.
The present system stores a preset number of words having the same row address before reading the words from the data register 30. Since the words all have the same row address the page mode write cycle of the DRAM is utilized to increase the speed of the transfer. The system is advantageous in environments such as graphics applications, where large amounts of data from the same page are transferred from the SYSTEM BUS to the DRAM. In a preferred embodiment, the state machine 20 asserts the DRAMREQ signal when the WCNT exceeds the RCNT by 8 words.
FIG. 3 is a timing diagram for the page mode transfer. In a preferred embodiment the data register 30 and address register 34 are two-port memories which can simultaneously write data to a storage location having an address specified by WCNT while reading data from a different storage location having an address specified by RCNT.
The SCLOCK signal 60 is supplied by an AT bus controller. In this example, data is being written to the data register 30 at a constant rate indicated by the WPTR signal 62 which is derived from SCLOCK 60. Thus, the WCNT signal 64 increases in value at a constant rate from an initial value of 00. A read clock signal 66 is generated by the state machine 20 and is supplied as the RPTR 68. Also, in the example, the value of RCNT 70 is initially 00. When WCNT 64 exceeds RCNT 70 by a predetermined value (in this case 08), the DRAMREQ signal 72 is asserted and, after a predetermined time, the RPTR 68 signal is generated to increment RCNT from 00 to 08 at a high page mode rate. RAS and CAS 74 and 76 signals are generated by the DRAM controller and derived from DRAMREQ 72 and the RPTR 68 signals to read the data output by the data register 30 utilizing the page mode to access storage locations specified by row addresses output by the address register 34.
As WCNT 64 is incremented, data is written from the DBUS 12 into the data register 30 at a storage location specified by WCNT while the corresponding column address is written from the ADRBUS 12 into the address register 34 at a storage location specified by WCNT 64. When WCNT is equal to 08 eight words in the same page have been stored in the data register 30. At that time the state machine 20 asserts DRAMREQ 72 and generates eight RPTR pulses 68 to increment RCNT from 00 to 08 while DRAMREQ is asserted to output the eight words previously stored in the data register 30 to the data input of the DRAM and to output the eight column addresses previously stored in the address register 34 to the address input of the DRAM.
The DRAM controller asserts RAS 74 for a predetermined amount of time when DRAMREQ 72 is received and pulses CAS 76 at the page mode rate to write the eight words output from the data register 30 at column locations specified by the eight addresses output by the address register 32. The row address for the eight words is supplied from the row address register 44. Note that the WCNT is incremented to 09 while the data is being output so that there is no latency with respect to writing data while data is being read from the PIBO FIFO 10.
The operation of the system when the row address changes will now be described. When SAMEPAGEN is asserted the state machine 20 operates as above-described and asserts DRAMREQ when WCNT exceeds RCNT by a predetermined amount. However, if SAMEPAGEN is deasserted to indicate a new row address on the ADRBUS 12 then the state machine 20 asserts FULLN to block incoming data until the PIBO 10 becomes empty and asserts FLUSHN to transfer all data stored in the data register to the DRAM. If more than one word is stored in the data register 30 then a page mode transfer is initiated.
Referring to FIG. 1, the ADRBUS 12 is coupled to the inputs of the row address latch 44 and comparator 42. Utilizing standard bus control signals, the comparator 42 compares a current row address stored in the row address latch 44 with a next row address provided by the ADRBUS 12 while a word having the current address is being stored in the data register 30. If the next row address is different from the current row address then the comparator deasserts SAMEPAGEN to transfer all data for the current row from the data register 30 to the DRAM while simultaneously writing data for the next row to the data register 30.
The invention has now been described with reference to the preferred embodiments. Alternatives and substitutions will now be apparent to persons of skill in the art. Accordingly, it is not intended to limit the invention except as provided by the appended claims.
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A page in, burst-out FIFO buffer that stores only words in a single page and transfers the words to a DRAM utilizing a page mode transfer to increase data throughput and decrease latency offloading DRAM bandwidth.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
Applicant's invention relates to a purified natural zeolite pigment that can be used as a microparticle retention aid that produces a paper that exhibits improved characteristics over existing papers made with other retention aids.
2. Background Information
Paper is a complex composite made up of a combination of biological, synthetic, and inorganic materials. The components include wood pulp or other fibers and fines (as well as other components of wood), inorganic (mineral) and organic fillers, natural and synthetic polymers (for sizing, retention and strength), and other additives to meet specific product or process requirements. Retention of the individual components in appropriate amounts is critical to the properties and quality of the paper sheet as well as minimizing pollution and cost.
Retention has been defined in the literature as the term used to describe the effectiveness of a given process to retain the components of the paper sheet or to describe the ability of a given material to be retained. 1 Retention describes the amount of a given material in the final product relative to the amount present at some earlier stage in the process. 1 Scott, W. E., Principles of Wet End Chemistry TAPPI Press: Atlanta (1996), p. 111.
In the past decade, retention has gained even more importance due to many changes in the paper industry. Paper machines have become bigger and run faster. Most fine paper mills have converted to alkaline papermaking conditions. This has permitted the use of new and less expensive filler systems, predominately calcium carbonate in some form (precipitated, ground, or chalk). In addition to a cost advantage, these fillers impart properties needed to meet more stringent product requirements. For example, very often the same sheet is expected to be suitable for both ink-jet printing and xerography. Generally the filler content of the sheet has increased and is likely to continue to increase. The switch to alkaline papermaking conditions has also resulted in a change in sizing chemistries. Synthetic sizes such as ASA (alkenyl succinic anhydride) and AKD (alkyl ketene dimer) are the predominant sizes used in alkaline papermaking. 2 How they interact with other components of the sheet and how and where they are retained is critical to the properties of the sheet. There are now trends toward neutral or alkaline conditions and increased filler usage in wood containing grades also. AS paper manufacturers recognize the costs of poor retention in terms of pollution abatement and product loss, they are striving to reduce or eliminate effluents from their mills. All these factors combine to make retention of papermaking materials one of the most important processes of the wet end operation. 3 2 Gess, J. M., Tappi Journal 75 (4): 80 (1992).3 Doiron, B. E., 1994 TAPPI Papermakers Conference Proceedings , TAPPI Press: Atlanta (1994), p. 603.
Retention of the various components of the stock in the final sheet is generally considered to be due to chemical, mechanical, or a combination of both mechanisms. While the dissolved materials are retained by adsorption or chemical bonding to the suspended solids, the suspended solids are retained by mechanical filtration or entrapment with the forming web of fiber, or preferably by physico-chemical attachment to the fibers, which are much larger, or to one another. This will occur to some degree regardless of attractive or repulsive forces between the particles. Because of their relatively small size, the particles which make up the fines fraction (inorganic fillers and cellulosic fines) are difficult to retain in the web, and much more of this material would pass through the wire and end up in the white water system if it were not for the addition of retention aids which enhance the colloidal retention of the fines fraction. Retention aids are water-soluble polyelectrolytes which cause the fines fraction to flocculate either with themselves or by adsorption onto the long fiber portion of the furnish, thus bringing about greater retention by both chemical and mechanical means.
Theory says there are two ways in which the fine particles in a papermaking web can be retained through physicochemical mechanisms:
1. By gathering the fine particles into a macroparticle. 2. By attaching the fine particles to the large fibers that are in turn retained at a 100% level.
As a rule, agglomeration, flocculation or coagulation is accomplished by changing the charge of one particle in relation to another. This is done by adding a high cationic charge density, low molecular weight polymer (in the case of an acid papermaking system) to a papermaking furnish. It is expected that the fiber fines and small filler particles, because of their higher surface area in comparison to fibers, interact preferentially with the polymers. The high charge density of these polymers will cause the formation of cationic spots on the filler particles and fiber fines. It then is hypothesized that the cationic centers on the filler particles and fiber fines will be attracted to the anionic centers on the fibers, and this will result in the retention of the fines and small filler particles with the fibers. Too high of a dose of agglomerant or coagulant will result in fiber-fiber repulsion and a loss in retention.
The terms agglomeration, flocculation and coagulation are often used interchangeably in papermaking. Agglomeration or flocculation was used by those working directly with paper machine personnel, while coagulation was used by those personnel working in water treatment. Agglomeration or flocculation is that interaction that occurs between oppositely charged materials. Coagulation, on a purely theoretical level, tends to be formation of macroparticles that occurs when the zeta potential of a system approaches zero and there is a maximum physicochemical interaction between the elements of the furnish.
Microparticle retention systems are considered to influence fine particle retention through a physicochemical mechanism of coagulation. Such a mechanism has long been thought to have the greatest impact on small particle retention. 4 4 Unbehend, J. E, Tappi 59 (10): 74 (1976).
Modern microparticle systems include both soluble polyelectrolytes and a very small (5–10 nm) highly charged “microparticle” to destabilize a given colloidal particle suspension through a complex mechanism. Usually inorganic in nature, these particles typically possess a large anionic surface charge. Used in combination with soluble polyelectrolytes, such as cationic starch or polyacrylamides, wither cationic or anionic, microparticle retention systems provide a very powerful tool for optimizing retention.
Colloidal silica is the predominant microparticle used in papermaking retention systems today. The original colloidal silica micro particle introduced to the paper industry was a stable colloidal dispersion of spherical amorphous silica particles, about 5 nm in size. 5 A variety of particle sizes and three-dimensional silica sol structures have been presented in the last ten years. 6 Some of the three-dimensional silica aggregate structures have overall aggregate size small enough (20–50 nm) to maintain the colloidal dispersion properties of the individual silica particle. 5, 7 5 Sunden, O., Batelson, P. G., Johansson, H. E., Larsson, H. M., and Svenging, P. J., U.S. Pat. No. 4,388,150 (Jun. 14, 1983).6 Johansson, H., International Patent WO 95/23021 (Aug. 31, 1995).7 Moffett, R. H., Tappi Journal 77 (12): 133 (1994).
One of the silica aggregates has been developed specifically to work with high-charged cationic polyacrylamide. This product is a highly branched, three-dimensional, silica aggregate with an overall particle size of approximately 50-nm. 7 Moffett reported that the highly structured, larger sized silica aggregates appear to be the most efficient silica particles used in conjunction with a wide range of cationic polyacrylamides. 7 7 Moffett, R. H., Tappi Journal 77 (12): 133 (1994).
It can be seen that one of the shortcomings of silica microparticle systems is the need to use different physical structures for the various papermaking applications. Another limitation on the use of silica microparticle retention aids is their very high cost.
Colloidal bentonite clay with a high smectite component, specifically montmorillonite, is another mineral commonly used in microparticle retention systems. The attribute similar to the silica microparticles is the high surface area and high charge on the particle, which, in combination, promotes the coagulation mechanism of retention of small fillers and fines. Colloidal bentonites that are effective in microparticle systems are three-dimensional particles that are up to 300 nm long and have a very thin, uniform thickness of less than 1 nm. 8 High purity montmorillonite is critical for using colloidal bentonites as a microparticle in retention systems. 8 8 Kundson, M. I., 1993 TAPPI Papermakers Conference Proceedings , TAPPI Press: Atlanta, 1993, p. 141.
Other types of inorganic microparticle retention systems have been presented in the literature. 9,10,11 The filler retention performance of the system based on aluminum hydroxide in-situ in conjunction with cationic starch is close to that of silica and bentonite-based microparticle systems. From an economic standpoint, the level of cationic starch needed results in an expensive system and can result in paper quality problems, such as poor sheet formation. Additionally, because of the unique pH-dependent distribution of alumina species, fines retention is very dependent upon pH. While good retention performance can be obtained in a pH range from 7.8–8.6, a pH drop to only 7.5 can result in a 25% reduction in fines retention. 12 9 Bixler, H. J. and Peats, S., U.S. Pat. No. 5,071,512 (Dec. 10, 1990)10 Jokinen, O. J. Petander, L. and Virta, P. J., U.S. Pat. No. 4,756,801 (Jul. 12, 1988).11 Gill, R. A. and Sanders, U.S. Pat. No. 4,892,590 (Jan. 9, 1990).12 Gill, R. I. S., Paper Tech., 32(8): 34 (1991).
Existing microparticulate retention aids, namely silica and bentonite, have many disadvantages, so a goal of the present invention was to develop a microparticle retention system that incorporates a zeolite pigment with at least the same or superior qualities to those of the existing microparticles.
A zeolite pigment that possesses the desirable combination of brightness, color, particle size distribution, surface area, internal void volume, rheology and hardness could also be useful in overcoming the limitations of conventional and other specialty pigments in various papermaking and paper coating applications including but not limited to: (1) more economical microparticle retention system chemistry; (2) toner bond improvement in laser and other dry toner imaged digital papers; (3) elimination of smudging and improvement of print quality in direct print flexography on coated linerboard used in corrugated containers; (4) elimination of print through on newsprint and ultra light weight coated papers; (5) improvement of dot fidelity and print quality on coated rotogravure printing papers; (6) low abrasion extender for titanium dioxide pigments; (7) improvement of coefficient of friction of paper and paperboard; (8) production of technical specialty papers such as anti-tarnish, gas filtration, and absorbent papers with improved properties and lower cost of manufacture; (9) additive to improve the efficiency of deinking systems; (10) additive to reduce problems with pitch, stickies and/or other organic deposits in pulping and papermaking systems.
Zeolites are crystalline, hydrated aluminosilicates of the alkali and alkaline earth metals. More particularly, zeolites are framework silicates consisting of interlocking tetrahedrons of SiO 4 and AlO 4 . In order to constitute a zeolite, the ratio of silicon and aluminum to oxygen must be 2. The aluminosilicates structure is negatively charged and attracts the positive cations that reside within. When exposed to higher charged ions of a new element, zeolites will exchange the lower charged element contained within the zeolite for a higher charged element. Unlike most other tectosilicates, zeolites have large vacant spaces or cages in their structures that allow space for large cations such as sodium, potassium, barium, and calcium and relatively large molecules and cationic molecules, such as water, ammonia, carbonate ions, and nitrate ions. In most useful zeolites, the spaces are interconnected and form long wide channels of varying sizes depending on the mineral. These channels allow ease of movement of the resident ions and molecules into and out of the structure.
Zeolites are characterized by 1) a high degree of hydration, 2) low density and large void volume when dehydrated, 3) stability of the crystal structure of many zeolites when dehydrated, 4) uniform molecular sized channels in the dehydrated crystals, 5) ability to absorb gases and vapors, 6) catalytic properties, and 7) cation exchange properties.
There are several mentions of the use of synthetic zeolites as a wet end additive in papermaking. In U.S. Pat. No. 4,752,314 Rock teaches the use of a combination of titanium dioxide and synthetic Zeolite A wherein the sodium has been at least partially replaced with calcium and/or hydronium ion to improve the optical properties of paper. Rock teaches that the Zeolite A must have a composition: Zeolite (Ca.sub.x Na.sub.y)A zH.sub.2 O where x is in the range of 0.3 to 3.6, y is in the range of 9.6 to 11.85 and z is in the range of 20 to 27 or Zeolite (Ca.sub.x Na.sub.y Hy) zH.sub.2 O where x is in the range of 0 to 4.8, y is in the range of 0.6 and z is in the range of 20 to 27.
In U.S. Pat. No. 5,900,116 Nagan teaches the use of a synthetic zeolite crystalloid coagulant with particle size 4 to 10 nm in combination with cationic acrylamide polymer as a papermaking retention aid.
The use of natural zeolites in paper making has a long history, but has been almost unique to Japan where zeolite has been used as filler to improve bulkiness and printability. 13 Natural zeolites have also been used as fillers for paper in Hungary. These natural zeolites however are a low brightness material and this renders it unsatisfactory for application in the United States on uncoated office paper and on coated ink jet paper where high brightness is expected. 13 Japanese patent application No. 45-41044 with disclosure date Dec. 23, 1970.
Numerous families of natural zeolites exist and each has varying characteristics. Unfortunately, natural zeolites exhibit nonuniform properties that make them difficult to work with in many applications because ores from one location can vary with any other. It is however possible to manufacture zeolites with uniform properties. The preferred zeolite for use in the present invention is a processed form of the natural mineral clinoptilolite which is a hydrated sodium potassium calcium aluminum silicate having the formula (Na, K, Ca) 2-3 Al 3 (Al,Si) 2 Si 13 ) 36 -12H 2 O. This zeolite is within the family Heulandite that also includes the mineral heulandite, which is a hydrated sodium calcium aluminum silicate. The physical characteristics of raw clinoptilolite are listed in Table 1.
TABLE 1
PHYSICAL CHARACTERISTICS OF CLINOPTILOLITE
Color is colorless, white, pink, yellow, reddish and pale brown.
Luster is vitreous to pearly on the most prominent pinacoid face and on
cleavage surfaces.
Transparency: Crystals are transparent to translucent.
Crystal System is monoclinic; 2/m.
Crystal Habits include blocky or tabular crystals with good monoclinic
crystal form. More tabular and proportioned than heulandite.
Also commonly found in acicular (needle thin) crystal sprays.
Cleavage is perfect in one direction parallel to the
prominent pinacoid face.
Fracture is uneven.
Hardness is 3.5 B 4, maybe softer on cleavage surfaces.
Specific Gravity is approximately 2.2
Streak is white.
Clinoptilolite's structure is sheet like with a tectosilicate structure where every oxygen is connected to either a silicon or an aluminum ion (at a ratio of [Al+Si]/0=2). The sheets are connected to each other by a few bonds that are relatively widely separated from each other. The sheets contain open rings of alternating eight and ten sides. These rings stack together from sheet to sheet to form channels throughout the crystal structure. The size of these channels controls the size of the molecules or ions that can pass through them. Clinoptilolite is well suited for various applications, such as in paper coating compositions, because it exhibits large pore space, high resistance to extreme temperatures, and has a chemically neutral structure.
The zeolite of the present invention is not anticipated by either Rock in U.S. Pat. No. 4,752,341 or Nagan in U.S. Pat. No. 5,900,116. The structure of the natural zeolite of the present invention falls outside of the range of structures specified by Rock in U.S. Pat. No. 4,752,341. The particle sizes of the natural zeolite of the present invention are 2 to 3 orders of magnitude greater than the 4 to 10 nm specified by Nagan in U.S. Pat. No. 5,900,116.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a novel purified natural zeolite pigment that can be used as a microparticle in a retention aid system.
Another object of the present invention is to provide a novel purified natural zeolite that can be used as a catalyst in chemical processes.
In satisfaction of these and related objectives, Applicant's present invention provides a purified natural zeolite pigment that can be used as a microparticle for a retention aid system. Applicant's invention permits its practitioner to manufacture paper that exhibits improved characteristics over existing papers such as high print quality images and reduced cost. It also permits the practitioner to make other specialty and technical papers that exhibit quality and economic advantages over papers made with existing technology and commercially available materials.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graph of the dynamic contact angle versus time for compositions both with and without zeolite pigment.
FIG. 2 is a graph of Britt Jar™ speed versus % filler retention for ZO Brite-1, ZO Brite-3 and silica.
FIG. 3 is a graph of Britt Jar™ speed versus % filler retention for ZO Brite-1 and ZO Brite-1 new.
FIG. 4 is a graph of Britt Jar™ speed versus % filler retention for bentonite, ZO Brite-1 and ZO-Brite-3.
FIG. 5 is a graph of Britt Jar™ speed versus % filler retention for ZO Brite-1, ZO Brite-Select and silica.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The processed zeolite used in the present invention has several specific characteristics as indicated in Table 2.
TABLE 2
Characteristics of Zeolite Pigment Samples
Zeolite Pigment
Zeolite Pigment
Specification
Sample 1
Sample 2
GE Brightness 14 %
94+
90+
L 15
98.46
98.00
a
0.43
0.44
b
1.25
1.72
Yellowness Index
2.48
2.05
Particle Size μ, <D90
2.0
2.0
Einlehner Abrasion, mg loss
12
18
Loose Density, lbs./cu.ft.
8
8
Packed Density, lbs./cu.ft.
12
12
Refractive Index
1.48
1.48
Surface Area, sq.m./g.
40–50
40–50
Oil Absorption, lbs./100 lbs.
70–80
70–80
Density, g/cc
2.2
2.2
pH in Water
5.0
8.5
Cation Exchange Capacity
1.6–1.8
1.8–2.0
Brookfield Viscosity, 20 rpm
1000 cPs
1000 cPs
@ 40% solids*
Hercules Viscosity
1 dyne
1 dyne
@ 1100 rpm*
*Nonoptimized dispersion in water
14 GE Brightness is a directional brightness measurement utilizing essentially parallel beams of light with a wavelength of 457 nm to illuminate the paper surface at an angle of 45°. It is also referred to as TAPPI Brightness. GE or TAPPI Brightness is the value obtained by TAPPI Test method T646 om-94 “Brightness of Clay and Other Mineral Pigments” (45 degrees/0 degrees).
15 L, a, b values are the chromacity coordinates or color values of paper or paperboard measures with tristimulus filter colorimeters or spectrophotometers incorporating direction (45°/0°) geometry and CIE (International Commission on Illumination) illuminant C. “L” represents lightness, increasing from zero for black to 100 for white; “a” represents redness when plus, greenness when minus and zero for gray; “b” represents yellowness when plus, blueness when minus, and zero for gray. This is referred to as TAPPI Test Method T 524 om-94 “Color of Paper and Paperboard (45°/0° Geometry).”
Pilot paper machine trials were run comparing the use of the zeolite of the present invention to precipitated calcium carbonate (PCC) as filler. The trials showed significant advantages of the present zeolite pigment as filler. These pilot machine filler trials were run without use of retention aid polymers. It was found that the filler retention for the present zeolite was 2.5 to 4 times as high as PCC, which facilitates running a cleaner wet end with improved sheet formation and uniform optical properties. The significantly higher retention achieved with the zeolite of the present invention is an indication that it can perform well as a substitute for silica or bentonite in microparticulate retention systems. Silicas currently used in this application are not cost effective. The improved retention of the zeolite pigment is an indication that it would be useful as an alternative to costly silica as a deinking aid.
In addition, porosity tests showed that the present zeolite produced a more open sheet, which would facilitate the use of this pigment in specialty gas filtration papers and anti-tarnish papers. It was also found that the zeolite pigment of the present invention produced papers that had higher tensile strength and tensile energy absorption or stretch. Papers filled with the present zeolite also had a higher coefficient of friction, which decreases the likelihood of misfeed and jams in copiers and also improves performance in converting equipment and print shops. The zeolite of the present invention can also be useful as a frictionizer for coefficient of friction control in recycled linerboard.
The capability of the zeolite pigment to reduce print-through was evaluated by printing samples from the pilot paper machine trials on a proof press and visually inspecting them for evidence of print show-through. The control sample with no filler showed severe print-through. The sample filled with 100 pounds of zeolite pigment (4.59% measured ash content) showed no evidence of print-through. Samples filled with PCC at levels up to 250 pounds per ton showed little improvement over the unfilled control with regard to print-through. The superior performance of the zeolite pigment in minimizing print-through is an indication that it would be useful in production of ultra lightweight-coated publication papers.
Microparticle Retention Systems
EKA's Compozil™ system using colloidal silica has become a standard against which other microparticulate retention systems are measured for highly-filled papermaking systems. Another very popular microparticle system in use is Ciba's Hydrocol™ system utilizing bentonite as the mineral microparticle. While there are other (colloidal polymer) microparticle systems in use, silica and bentonite dominate the mineral pigment sector of these systems.
Many laboratory devices and test methods have been developed in order to enable the investigator to evaluate pulps, retention aids, fillers, and other additives without resorting to a trial on a full-size paper machine. These include modifications of devices used to measure freeness and handsheet making equipment as well as devices designed specifically to measure retention.
Standard handsheet making equipment such as a British hand sheet mold equipped with a means of re-circulating white water can prove useful in laboratory studies. The advantage, in addition to being fast and simple, is that the resulting handsheets can also be tested. However, these are static methods and do not simulate the turbulence and shear forces that the furnish would be subjected to on a paper machine.
The Dynamic Drainage Jar developed by Britt and Unbehend attempts to simulate conditions encountered on a paper machine. 16 The device determines the relative tendency of the fines fraction to pass through the screen with the fluid phase or to remain adsorbed as a part of the solid phase. The result is expressed as retention of the fines fraction under selected and controlled turbulence conditions. 16 Li, H. M., and Scott, W. E, 2000 TAPPI Papermakers Conference Proceedings , TAPPI Press: Atlanta (2000), p. 1.
Because it is not possible to duplicate the performance of a paper machine in an experimental device without in effect building an experimental paper machine with all the complexity of a real paper machine, Britt and Unbehend argue that a laboratory device which measures the relative tendency of the fines fraction to be retained or to follow the water over a range of turbulence would be useful in evaluating retention for a wide range of machines. This is what the Dynamic Drainage Jar was designed to do, and it has been accepted as the industry standard throughout the world.
Because of the wide range of papermaking furnish combinations in commercial practice, our focus in this study was to identify a model system that would generate the most useful information for the intended initial screening. Value-adding pigments are most often found to be used in significant quantities in bleached free sheet furnishes, rather than in wood-containing (newsprint or magazine) or unbleached chemical (corrugated container) pulp systems. To that end, a general furnish of bleached northern kraft pulp was chosen, with a 60% hardwood (HW), 40% softwood (SW) blend refined to a Canadian Standard Freeness 17 of approximately 420 ml. 17 Canadian Standard Freeness is a measure of how much water a given papermaking pulp suspension will ‘hold’ under simple gravity. It is designed to give a measure of how easily a dilute suspension of pulp (3 grams in 1 Liter of water) may be drained. This is important in the papermaking process because it influences the amount of power needed to run the machine and ultimately the speed at which the machine may operate.
There are several important paper properties that are developed or enhanced by the addition of pigments (fillers), but the first challenge of papermaking is to keep the added pigments in the sheet during web formation and consolidation 18 from a suspension that is more than 99% water. This challenge is most often called “filler retention.” The classical method for evaluating filler retention potential is by the use of a dynamic drainage device, typically called a Britt Jar™. This screening evaluation was conducted using a Britt Jar™ at several internal propeller speeds to simulate paper machines running over a wide range of line speeds. 18 Web formation is defined as creating a loosely combined sheet structure, typically with fibers or filaments, which are consolidated (bonded) through any number of web methods. Web formation processes include spun bonded and spun melt composites, melt blown, carded, wet laid, air laid and porous film. Web consolidation processes include thermal bonded, resin or chemical product, spunlaced or hydroentangled, thru-air bonded, needle punched, and stitchbonded.
Pigments involved in this study were scalenohedral 19 precipitated calcium carbonate (PCC), the zeolite of the present invention, bentonite, and colloidal silica. The overall purpose of this study was to evaluate the zeolite of the present invention as a potential filler to a papermaking furnish and to evaluate the zeolite of the present invention as a potential contributor to a microparticle retention system in a rather highly-filled papermaking furnish. Specifically concerning the microparticulate retention system, the present inventors wanted to determine (1) if the zeolite of the present invention had the potential to replace colloidal silica or bentonite and (2) if so, is there any significant difference in performance among the different grades of zeolite of the present invention when used to replace the colloidal silica and bentonite. In order to determine the potential of the zeolite pigment of the present invention as a filler and in a microparticulate retention system, several zeolite pigment samples were used. The samples were designated as ZO Brite-1, ZO Brite-1 new, ZO Brite-select and ZO Brite-3 and their characteristics are listed in Table 3. 19 A scalenohedron is a six-sided polyhedron, similar to a bipyramidal hexagon, but the adjoining area at the center is diagonal between every side as opposed to being level. Other modifications might also be present.
TABLE 3
Specifications for ZO Brite-1, ZO Brite-1 new,
ZO Brite-3, and ZO Brite-select samples
ZO
ZO Brite-1
ZO
ZO
Specifications
Brite-1
new
Brite-3
Brite-select
GE Brightness
92+
94+
90+
90+
L
97
98
96
96
a
−0.1
−0.3
0.44
0.33
b
1.45
1
1.72
1.72
YI Yellowness
2.25
2
2.5
2.5
Index
Particle Size
2
2
2
0.5
u < D90
Einlehner
12
12
18
18
Abrasion
Loose Density
4 to 8
4 to 8
4 to 8
0.1–0.2
(lbs/cu.ft)
Packed
12 to 16
12 to 16
12 to 16
2–4
Density (lbs/cu.ft)
Refractive
1.48
1.48
1.48
1.48
Index
Surface Area
40 to 50
40 to 50
40 to 50
2400–3200
(sq.m./g)
Oil Absorption
70 to 80
70 to 80
70 to 80
NA
(lbs/100 lbs)
Density (g/cc)
2.2
2.2
2.2
2.2
pH in water
5
5
8.5
8.5
Cation
1.0–2.0
1.0–2.0
1.0–2.0
1.0–2.0
Exchange
meq/g
meq/g
meq/g
meq/g
Capacity
Brookfield
820
820
27.5
NA
Viscosity
(cP @ 20 rpm)
Hercules
138
138
1
NA
Viscosity
(kilodyne-
cm @ 1100 rpm
As mentioned earlier in the specification, the present zeolite showed promise as filler in a papermaking furnish. That work was conducted at relatively low paper machine speed, about 200 fpm. These results were confirmed with the Britt Jar™ run at 500 rpm. Total solids retention with PCC was about 85% and with the present zeolite it was about 98%. Total solids retention remained very high with the present zeolite when used as the filler, even as Britt Jar™ speed was increased to 1500 rpm, as shown in Table 4. This was entirely unexpected.
TABLE 4
Total solids retention with varying Britt Jar ™ speeds
Pigment
500 rpm
1000 rpm
1500 rpm
20% PCC
85%
78%
78%
20% ZOBrite-1
98%
98%
98%
These experiments were run with no retention aid added to the furnish and adjusted to pH 8. Even though these data represent total solids retention rather than retention of filler alone, they suggest that even under relatively high-shear conditions found on fast paper machines, the present zeolite may have a natural tendency to be retained in the sheet. The possibility exists that addition of the present zeolite as papermaking filler could reduce the need for expensive retention aids.
A series of Britt Jar™ runs were performed using a filler loading of 20% PCC. A suitable base retention aid system for this model furnish was determined to be 2 lb/ton cationic retention aid and 5 lb/ton cationic starch.
The summary data are presented below in Tables 5a–5c based on varying Britt Jar™ speeds.
TABLE 5a
Britt Jar ™ results @ 1500 rpm
% filler retention
Std.
Microparticle
(avg.)
deviation
None
15.9
5.23
1 lb/ton silica
48.7
1.37
1 lb/ton ZO Brite-1
47.0
0.14
1 lb/ton ZO Brite-select
51.4
0.97
1 lb/ton ZO Brite-1 new
45.3
3.46
1 lb/ton ZO Brite-3
49.0
1.22
2 lb/ton bentonite
47.7
1.52
4 lb/ton bentonite
54.8
1.01
TABLE 5b
Britt Jar ™ results @ 1000 rpm
% filler retention
Std.
Microparticle
(avg.)
deviation
None
50.7
3.52
1 lb/ton silica
63.6
0.64
1 lb/ton ZO Brite-1
63.6
0.35
1 lb/ton ZO Brite-select
64.6
1.07
1 lb/ton ZO Brite-1 new
60.9
3.98
1 lb/ton ZO Brite-3
68.7
0.53
2 lb/ton bentonite
68.9
2.7
4 lb/ton bentonite
71.8
0.8
TABLE 5c
Britt Jar ™ results @ 500 rpm
% filler retention
Std.
Microparticle
(avg.)
deviation
None
97.8
0.98
1 lb/ton silica
85
2.23
1 lb/ton ZO Brite-1
89.8
1.46
1 lb/ton ZO Brite-select
85.6
1.38
1 lb/ton ZO Brite-1 new
84.1
1.8
1 lb/ton ZO Brite-3
96.9
1.26
2 lb/ton bentonite
94.8
2.01
4 lb/ton bentonite
93.4
2.68
The data in Table 5a represent the results one might expect on a relatively fast paper machine. Based on these runs, it was determined that adding a silica microparticle to the base retention aid system significantly improves filler retention, there is no statistical difference in performance between the silica used and ZO Brite-1 as a microparticle for filler retention, and there is no statistical difference in performance between ZO Brite-1 and ZO Brite-1 new as a microparticle for filler retention. However, it may be noteworthy that there is a large difference in the variation of performance of ZO Brite-1 new, compared to that of ZO Brite-1, as evidenced by the difference in standard deviations within each run. There is no statistically significant difference in performance between 2 lb/ton bentonite and 1 lb/ton ZO Brite-1 as a microparticle for filler retention. There is no statistically significant difference in performance between 2 lb/ton bentonite and 1 b/ton ZO Brite-3 as a microparticle for filler retention. But there is a statistically significant improvement in filler retention when using 4 lb/ton bentonite compared to using 2 lb/ton bentonite. This difference also exists when comparing 4 lb/ton bentonite to 1 b/ton ZO Brite-1 or 1 lb/ton ZO Brite-3. There is a statistically significant improvement in filler retention when using 1 lb/ton ZO Brite-select compared to using silica or ZO Brite-1. There is a statistically significant improvement in filler retention when using 1 lb/ton ZO Brite-select compared to using 2 lb/ton bentonite. 4 lb/ton bentonite generated better filler retention than 1 lb/ton ZO Brite-select when used as a microparticle for filler retention. Similar data were generated at Britt Jar™ speeds of 1000 rpm and 500 rpm. These are presented in Tables 5b and 5c.
The figures in the present application help illustrate the differences in performance that may exist between microparticles in this retention system under different paper machine operating speeds. This illustrates why retention aid systems need to be specifically tailored for a particular paper machine and grade of paper. The most significant conclusion from studying each of the following figures is that the present zeolite shows substantial promise as a microparticle for retention aid systems.
FIG. 2 illustrates the relative performance of the present zeolite, specifically ZO Brite-1 and ZO Brite-3, with silica over a range of Britt Jar™ speeds. The x-axis shows the range of Brift Jar™ speeds, 500 rpm, 1000 rpm and 1500 rpm, while the y-axis represents the % filler retention. At 500 rpm ZO Brite-1 and ZO Brite-3 have only slightly higher % filler retention than silica. Although visually encouraging, there is no statistical difference in performance between silica and ZO Brite-1 or ZO Brite-3 as a microparticle for filler retention at 500 rpm. When the speed is increased to 1000 rpm, the % filler retention for ZO Brite-1 and silica are the same with only ZO Brite-3 having a slightly higher % filler retention. At 1500 rpm, ZO Brite-1, ZO Brite-3 and silica show no significant difference in % filler retention. The present zeolites perform at least as well as silica over the entire range of Brift Jar™ speeds
FIG. 3 illustrates the relative performance of two zeolites of the present invention, namely ZO Brite-1 and ZO Brite-1 new. The x-axis shows the range of Britt Jar™ speeds, 500 rpm, 1000 rpm and 1500 rpm, while the y-axis represents the % filler retention. At 500 rpm, ZO Brite-1 had a higher % filler retention than ZO Brite-1 new. When the speed was increased to 1000 rpm, ZO Brite-1 had only a slightly higher % filler retention than ZO Brite-1 new. At 1500 rpm, the % filler retention for ZO Brite-1 and ZO Brite-1 new showed no significant differences.
While these two pigments appear to perform comparably, there is a statistically significant decrease in performance of ZO Brite- 1 new at low speed (500 rpm). While the difference at 1500 rpm is not statistically significant, it's most likely due to the variability of performance of the ZO Brite-1 new.
FIG. 4 illustrates the performance comparison between bentonite (2 lb/ton) and ZO Brite-1 and ZO Brite-3 (1 lb/ton). The x-axis shows the range of Britt Jar™ speeds, 500 rpm, 1000 rpm, and 1500 rpm, while the y-axis represents the % filler retention. There is no statistical difference between the bentonite performance (2 lb/ton) and that of the ZO Brite-1 or ZO Brite-3 (1 lb/ton) as the microparticle for filler retention, even at low speeds.
FIG. 5 illustrates the relative performance of silica, ZO Brite-1 and ZO Brite-select. The x-axis shows the range of Britt Jar™ speeds, 500 rpm, 1000 rpm and 1500 rpm, while the y-axis represents the % filler retention. At 500 rpm, ZO Brite-1 has a higher % filler retention than silica or ZO Brite-select. At 1000 rpm, each pigment shows approximately the same % filler retention. And at 1500 rpm, ZO Brite-select has a higher % filler retention than the other two pigments. As illustrated, there is a statistically significant improvement in filler retention at high Britt Jar™ speeds when using 1 lb/ton ZO Brite-select compared to using either silica or ZO Brite-1 as the microparticle in a retention aid system. It is evident from the data that the zeolite of the present invention can be used as a pigment filler for wet end addition, with a natural tendency to be retained at relatively high speeds, potentially reducing the need for retention aids.
The zeolite of the present invention can also be used in a microparticle retention aid system. ZO Brite-1 performed well against colloidal silica at comparable levels of addition. ZO Brite-1 also performed well at an addition level of 1 lb/ton against bentonite added at 2 lb/ton.
ZO-Brite-select, the smallest particle size tested for the zeolite of the present invention performed better at 1 lb/ton than either silica or ZO Brite-1 at comparable addition levels, and better than bentonite at 2 lb/ton.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.
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A microparticle retention aid for use in papermaking containing a high performance purified natural zeolite pigment is disclosed. Use of the pigment facilitates manufacture of papers with improved quality and economics. When used as filler, the novel zeolite pigment is readily retained and eliminates print-through in uncoated papers. The novel zeolite pigment is low in abrasion and provides improved coefficient of friction.
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BACKGROUND OF THE INVENTION
This invention relates to methods and apparatus for discriminating between the front and back surfaces of developed films.
The discrimination of the front and back surfaces of developed films in prior techniques was done by visually finding figures recorded on the films or by a manual judgement such as directly touching the films by hand. Such discrimination methods may always result in an inaccurate judegment, and particularly, the discrimination of the front and back surfaces of a mounted film (or slide film) which is fitted to a mount was very difficult. In addition, it will be necessary to take dirt or dust, or thermal deformation of the developed film into consideration as well as errors in assembling or working machine parts of an optical system for discriminating the surface (front or back) of the film.
SUMMARY OF THE INVENTION
A principal object of this invention is to provide methods and apparatus for easily and accurately discriminating between the front and back surfaces of a mounted film.
Another object of this invention is to provide a method and apparatus for the same purpose as described above when a glass-mount is used for protecting the mounted film from dirt, dust or thermal deformation.
A further object of this invention is to provide a calibration method applied to the surface discrimination methods and apparatus described above for mounted film or glass-mounted film for effectively amending or adjusting the discrimination methods.
According to this invention for achieving the objects described above, in one aspect thereof, there is provided a method for discriminating a surface of a developed film by detecting a position of an emulsion layer, i.e. a picture pattern formed on the developed film.
In another aspect of this invention, there is provided an apparatus for discriminating a surface of a developed film comprising an optical system for focusing a picture pattern on the film disposed on a reference position of the optical system, a first sensor located at a focused position of the picture pattern of the film when a front surface of the film is on the reference position, a second sensor located at a focused position of the picture pattern of the film when a back surface of the film is on the reference position, first and second band-pass filters operatively connected to the first and second sensors for extracting outputs therefrom within predetermined frequency ranges, respectively, first and second rectifiers operatively connected to the first and second band-pass filters for rectifying outputs therefrom, respectively, first and second integrators operatively connected to the first and second rectifiers for integrating outputs therefrom, respectively, and a comparator operatively connected to the first and second integrators for comparing outputs therefrom.
In a further aspect of this invention, there is provided an apparatus for discriminating a surface of a developed film comprising an optical system for focusing a picture pattern of the film disposed on a reference position of the optical system, a sensor arranged so as to be movable between a first focusing position of the picture pattern of the film when a front surface of the film is on the reference position and a second focusing position of the picture pattern of the film when the back surface of the film is on the reference position, a band-pass filter operatively connected to the sensor for extracting an output therefrom with a predetermined frequency range, a rectifier operatively connected to the band-pass filter for rectifying an output therefrom, an integrator operatively connected to the rectifier for rectifying an output therefrom, and a comparator operatively connected to the integrator for comparing the outputs from the integrator generated in cases where the sensor is positioned at the first and second picture pattern focusing positions.
In a still further aspect of this invention, there are provided a method and apparatus for discriminating a surface of a developed film in which is utilized a glass mounted film prepared by attaching glass sheets having the same thickness on both surfaces of the developed film.
In a still further aspect of this invention, there are provided a method and apparatus in which is utilized a calibration member prepared by a flat and non-deformable transparent base having one surface which is subjected to a picture treatment for amending or correcting errors caused in the measurements in the surface discrimination operation.
According to this invention, a front or back surface of a developed film can exactly be discriminated by detecting a position of an emulsion layer, i.e. picture pattern, formed on the film used in an optical system. The method and apparatus for realizing this fact are applicable to a glass mounted film, and in this example, the thickness of the glass-sheets attached to the developed film is preliminarily measured and the measured result can be introduced into the surface discrimination. In addition, errors or offset amounts caused in the measurements can be corrected or compensated for by utilizing a calibration method or member according to this invention. Thus, the surface of the developed film can be exactly discriminated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIGS. 1A and 1B are vertical sectional views showing the relationship of the front and back surfaces of a film to be applied to this invention;
FIGS. 2 and 3 are schematic views showing optical systems for explaining the principle of this invention;
FIG. 4 is a block diagram representing a main embodiment of this invention;
FIGS. 5A through 5F are graphs showing wave-form characteristics representing operation of the block diagram shown in FIG. 4;
FIG. 6 is a longitudinal sectional view of another embodiment of this invention;
FIGS. 7 and 9 are views showing structures of film surface detecting sensors used for the embodiments shown in FIG. 6;
FIG. 8 is a graph showing the characteristics of the sensor shown in FIG. 7 or 9;
FIGS. 10A and 10B are views for explaining the detection principle of the sensor shown in FIG. 7 or 9;
FIG. 11 is a graph representing the characteristic curve of the output of the sensor shown in FIG. 7 or 9;
FIG. 12 is a vertical sectional view showing a part of a glass mounted film;
FIGS. 13, 14A, 14B, 15A, 15B, 16A, 16B, 17A and 17B are views for explaining the principle of one embodiment of this invention when a glass-mounted film is used; and
FIGS. 18A and 18B are views for explaining a calibration method applied to the embodiments described above according to this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1A and 1B which briefly show a film 1 after the developing procedure; an emulsion layer 3 with a picture pattern is formed with a thickness x 1 (about 20-27 μm in the case of 135 mm-reversal film) from the front surface 2 of the film 1; a base layer 5 is also formed with a thickness x 2 (about 127 μm in the case of 135 mm-reversal film) from the back surface 4 of the film 1. A distance x 3 between the emulsion layer 3 with the front and back surfaces of the film 1 being contacted as shown in FIGS. 1A and 1B is about 100 μm. On the basis of the fact that there exists a difference of about 100 μm between the thicknesses of the emulsion layers 3 formed on the front and back surfaces of the film 1, surface discrimination of the film can be performed by detecting the positions of the emulsion layers 3 on the front and back surfaces 2 and 4 of the film 1.
For example, when a developed film 1 is set at a reference position So of an optical system 6 as shown in FIG. 2, the position of the emulsion layer 3 of the film 1 becomes offset with respect to the reference position So in accordance with the fact that the front or back surface of the film 1 contacts the reference position So. Taking the above fact into consideration, by focusing a picture pattern (emulsion layer 3) of the film 1 by using the optical system 6, the picture pattern is focused at a different position in accordance with the surface (front or back) of the film 1 contacting the reference position So. Namely, in FIG. 2, the dotted lines show a case where the front surface 2 of the film 1 contacts the reference position So and the picture pattern is focused at a position I and the solid lines show a case where the back surface 4 of the film 1 contacts the reference position So and the picture pattern is focused on a position II. Therefore, since the front or back surface of the film 1 contacts the reference position So, discrimination of the Focused position I or II can be accurately performed. This means in the other aspect that the picture pattern can be sharply focused at the position I but is defocused at the position II when the front surface 2 of the film 1 contacts the reference position So, and reversely, the picture pattern can be sharply focused at the position II but is defocused at the position I when the back surface 4 of the film 1 contacts the reference position So.
As described above, according to this invention, since the front or back of the film 1 contacts the reference position So, the discrimination of the focused position I or II can be accurately performed by the method comprising the steps of causing the film 1 to contact the fixed reference position So, focusing a picture pattern of the film 1 by means of the optical system 6, the disposing optical sensors or detectors at the positions I and II mentioned above so as thereby discriminate the focused conditions of the picture patterns at the positions I and II, i.e. to detect the position of the emulsion layer 3.
FIG. 3 shows a state that the emulsion layer 3, i.e. picture pattern, of the film 1 will be detected by using one optical sensor, which can be shifted from the position I to he position II or vice versa to detect the focused condition of the picture pattern on the positions I and II and to thereby discriminate the surface (front or back) of the film 1 contacting the reference position So.
In case of using an optical system 6 having the magnification of three times, a distance between the focused positions I and II is approximately 300 μm at the time when the front or back surface of the film 1 contacts the reference position So. Such a distance is sufficient for detecting the picture patterns at the positions I and II. The distance therebetween can of course be elongated by using an optical system having a magnification of more than three times.
FIG. 4 is a block diagram showing an apparatus realizing the discrimination method according to this invention, in which CCD (Charge Coupled Device) sensor units 10 and 20 are positioned at focused positions I and II, respectively, and band-pass filters (BPF) 11 and 21 are located for extracting outputs of the signals SF1 and SF2 from the CCD sensor units 10 and 20 at predetermined frequency ranges. The outputs of the signals FS1 and FS2 from the band-pass filters 11 and 21 are rectified by rectifiers 12 and 22. Signals RC1 and RC2, rectified by the rectifiers 12 and 22, are inputted into and integrated by integrators 13 and 23, respectively, and the integrated values TG1 and TG2 are then inputted into a comparator 30. The CCD sensor units 10 and 20 transmit electrical level (logic) signals representing the picture pattern or image of the film disposed in contact with the reference position So in accordance with the advance of the optical scanning lines, and the levels correspond to the image densities of the film.
With the construction described hereinabove, during one picture scan of the film set at the reference position So are outputted detected signals SF1 and SF2 from the CCD sensor units 10 and 20, for example, as shown in FIGS. 5A and 5C, respectively. At this operation, the frequency components of the signals SF1 and SF2 outputted from the CCD sensor units 10 and 20 correspond to the defocused conditions of the picture pattern of the film 1. In other words, since the defocused condition is in a small extent, when the picture pattern is sharply focused, a difference between densities of adjacent picture elements becomes large and the frequency component becomes high. On the other hand, when the defocused condition is in a large extent, the image density difference becomes low. In the illustrated example, the CCD sensor unit 10 outputs the signal SF1 with a low frequency and the CCD sensor unit 20 outputs the signal SF2 with a high frequency. These signals SF1 and SF2 are inputted respectively into the band-pass filters 11 and 21 and only the signal components within the predetermined frequency ranges are extracted, which are shown in FIGS. 5B and 5D, respectively. The low and high frequency components of the respective signals SF1 and SF2 are eliminated by the band-pass filters 11 and 21, from which the frequency components only in the predetermined ranges are then outputted. After the extraction of the signals SF1 and SF2 with the predetermined frequency components, those signals SF1 and SF2 are rectified and converted by the rectifiers 12 and 22 into d.c. components having only position components as shown in FIGS. 5E and 5F, respectively, and the d.c. components RC1 and RC2 are integrated by the integrators 13 and 23. In these cases, since the level of the integrated value TG1 from the integrator 13 becomes small and the level of the integrated value TG2 of the integrator 23 becomes large, the comparator 30 transmits a discrimination signal SB as an output of logic "1", for example, in comparison with these levels and discriminations the fact that the back surface of the film exactly contacts the reference position So. This is based on the fact that the higher the frequency component of the signal passing the band-pass filter, the larger becomes the level of the signal rectified by the rectifier. Namely, when the signal passing the band-pass filter has a high frequency component, i.e., when the defocused condition of the picture pattern of the film detected by the CCD sensor unit is small, the value integrated by the integrator becomes large. In the embodiment illustrated in FIG. 4, a pair of the CCD sensor units, the band-pass filters, the rectifiers, and the integrators are located, respectively, so that one CCD sensor unit is disposed at the position I and the other CCD sensor unit is disposed at the position II. However, in an alternative modification, one respective CCD sensor unit, band-pass filter, rectifier, and integrator may be located, and in this case, the CCD sensor unit is shifted from the position I to the position II or vice versa to thereby discriminate the defocused conditions of the focused images of the film on the positions I and II. In this modified embodiment, an integrated value by the integrator at position I or II is stored in a memory, for example, and the stored value is then compared by the comparator.
Since the principle of this invention resides in a discrimination of the surface (front or back) of a film made by detecting the position of an emulsion layer, i.e. the picture pattern with respect to the film surface, the discrimination thereof can be made by detecting the position of the emulsion layer relative to the position of the film surface.
FIG. 6 shows an embodiment of this invention realizing the fact described above. Referring to FIG. 6, a slide film 40 in which a film 45 is mounted is vertically fitted at a predetermined set position of a projection located at one end of a fixing member 41 which is not movable and to which a pulse motor 42 as a driving source is attached. The fixing member 41 includes a flat portion which extends from the projection and on this flat portion is mounted a sliding member 51 to which a cylindrical sensor unit 50 is secured, the sliding member 51 being provided with a longitudinal axial threaded bore into which a rotation shaft 52 is engaged so that the whole structure of the sensor unit 50 can be moved in an X 1 -X 2 direction when the shaft 52 is rotated. The rotation shaft 52 is itself supported by the fixing member 41 through a gear 53, located at one end thereof, which in turn is engaged with a gear 43 attached to the drive shaft of the pulse motor 42 to thereby move the sensor unit 50 in the X 1 -X 2 direction in accordance with the operation of the pulse motor 42.
In front of the slide film 40 fitted to the fixing member 41, is arranged at light source 44 which is used with a sensor 60 described below for optically detecting a picture pattern (emulsion layer) position. The sensor unit 50 is provided with a front portion having a shape for covering the fitted slide film 40 thereabove. The sensor 60 for optically detecting a film surface of the slide film 40 is attached to a plate 54 suspended from the endmost portion of the front portion of the sensor unit 50. A TCL (Through Camera Lens) module 70 is located at the rear end wall of the inner cylindrical portion of the sensor unit 50 for focusing the picture pattern of the slide film 40 with a lens system 71 and for detecting the position of the emulsion layer, i.e.--the picture pattern. The TCL module 70, the lens system 71, and the light source 44 constitute the picture pattern position detecting sensor of this invention.
Referring to FIG. 7, the film surface detecting sensor 60 comprises a light emitting element 61 such as light emitting diode and a photosensitive element 62 such as photodiode which are arranged side by side in the same direction. A light emitted from the light emitting element 61 is reflected by the film 45 and the reflected light is then received by the photosensitive element 62. Accordingly, in a case where the distance between the sensor 60 and the film 45 is considerably large, a relatively weak light reaches the surface of the film 45, and in this case, the reflected light reaches the photosensitive element 62 insufficiently and the level of the output signal is low. As the distance therebetween becomes small, the reflected light intensity as well as the light sensed increase. Moreover, in a case where the distance between the sensor 60 and the film surface 45 becomes very small, light emitted from the light emitting element 61 is emitted only on the surface of the film located at a position facing the light emitting element 61 and the light reflected from the film surface cannot be received by the photosensitive element 62 disposed at a position apart from the light emitting element, and the level of the output signal from the photosensitive element 62 reduces gradually.
The relationship of the output signal PS from the photosensitive element 62 with respect to the distance between the sensor 60 and the film 45 is shown in FIG. 8, in which a characteristic curve representing that relationship is shown. Thus, the distance therebetween can be obtained by the output signal PS from the photosensitive element 62 in light of the characteristic curve measured preliminarily, and the film surface can be detected by obtaining the peak of the characteristic curve.
FIG. 9 is an illustration showing another example of the film surface detecting sensor 60, in which a light is emitted on the film surface through a lens 64 and the reflected light is sensed through a lens 65 to improve the directivity of the light.
The TCL module 70 described hereinbefore is a CCD application element widely used in an automatic focusing mechanism of a camera, for example, as described in "SHASHIN KOGYO (Photographic Industry)" published on December, 1982 and "NIKKEI ELECTRONICS" published on Aug. 30, 1982. In a case where the picture pattern of the slide film 40 is focused on the photosensitive surface of the TCL module 70, the pulsating focus coincidence signal PC is transmitted, and in the other cases, a front or back focusing signal is transmitted. Accordingly, the picture pattern of the slide film 40 can be detected at a time when the focus coincidence signal PC from the TCL module 70 is transmitted in accordance with the picture or image projected on the photosensitive surface of the TCL module 70 through the lens system 71, and it is confirmed that such position corresponds to the emulsion layer position of the film 45.
In the structure described above, supposing that a position at which the output signal PS of the film surface detecting sensor 60 becomes maximum coincides with a focusing position of the picture pattern position detecting sensor, and that the coincidence position or point Po is realized on the left side of the film 45 as viewed in FIG. 10A or 10B, the rotation shaft 52 is rotated by the driving of the pulse motor 42 through the engagement of the gears 43 and 53 and the sliding member 51 in screw engagement with shaft 52 slides on the fixing member 41 to thereby shift the sensor unit 50 in the direction X 2 . According to the movement of the sensor unit 50 in the direction X 2 , the point Po also moves in the same direction by a distance of x 10 and finally reaches the left end surface of the film 45. In this case, if the front surface of the film 45 exists on the lefthand side thereof as shown in FIG. 10A, the peak value of the signal PS from the surface detecting sensor 60 is detected, and at the same time, a focus coincidence signal PC is transmitted from the TCL module 70 of the picture position detecting sensor, when the sensor unit 50 moves in the direction X 2 by the distance X so that the point Po will reach the front surface of the film 45. On the other hand, in a case where the back surface of the film 45 exists on the left hand side as shown in FIG. 10B, the focus coincidence signal PC is not transmitted from the TCL module 70 and only the signal PS from the film surface detecting sensor 60 reaches its peak, even if the point Po moves in the direction X 2 by the distance x to reach the back surface of the film 45. In the latter case, the TCL module 70 detects the picture pattern 46 and transmits the focus coincidence signal PC when the sensor unit 50 is further moved in the direction X 2 by the distance x 11 , i.e. the thickness of the base layer 47.
As described above, accordingly, the front or back surface of the film can be exactly discriminated by detecting a distance x between the peak detecting position of the film surface detecting sensor 60 and the output position of the focus coincidence signal PC from the TCL module 70 as shown in FIG. 11. More specifically, in a case, shown in FIG. 10A, where the front surface of the film is on the lefthand side thereof, the distance x becomes zero, and in a case, shown in FIG. 10B, where the back surface of the film is on the lefthand side thereof, the distance x becomes x 2 , i.e. the thickness x 11 of the base layer 47 of the film.
Although in the aforementioned example, a case where the point Po exists on the left side of the film 45 is discussed, it should of course be understood that substantially the same discussion will be applied to a case where the point Po exists on the right side of the film 45 and the sensor unit 50 is shifted in the direction X 1 as shown in FIG. 6 to discriminate the surface (front or back) of the film 45. A film applicable to this invention is a developed film having positions of the picture patterns different on the front and back surfaces thereof.
Although with the preferred embodiment of this invention mentioned hereinbefore, a normally mounted film is referred to, this invention can be applicable to a glass-mounted film, which is generally prepared by attaching thin glass sheets, having the same thickness, to both sides of the mounted (slide) film for protecting a developed film from dirt, dust, or thermal deformation at a sliding time.
In the former embodiments, it is supposed that the position (called hereinafter position or point P 1 ) at which the output signal PS from the surface detecting sensor 60 becomes maximum would completely coincide with a focusing position (called hereinafter position or point P 2 ) of the picture pattern position detecting sensor. However, when a glass-mount film as shown in FIG. 12 is used, the distance x in the former embodiment shown in FIG. 11 includes an offset distance Hg which corresponds to the thickness of the glass sheets 48 and 49 attached to the mount film.
Taking the above fact into consideration, a further modified embodiment according to this invention will be described hereunder for discriminating the front or back surface of a glass-mount film by compensating for the offset of the distance x caused by attaching the glass sheets each having the thickness Hg, for example.
Referring to FIG. 13, sensors 60A and 60B for detecting the film surface are disposed at positions interposing the glass-mount film 45A therebetween with a predetermined distance x 12 . A distance a 1 between the surfaces of the sensor 60A and the glass sheet 48 is obtained by shifting the glass-mounted film 45A until the sensor 60A generates the maximum output signal, and a distance a 2 between the sensor 60B and the surface of the glass sheet 49 is obtained by shifting the glass-mount film 45A until the sensor 60B generates the maximum output signal. The thickness Hm of the glass-mount film 45A is calculated as follows:
Hm=x.sub.12 -(a.sub.1 +a.sub.2) (1)
Supposing that the glass sheets 48 and 49 on both sides of the film had the same thickness of Hg, the thickness Hg can be obtained as follows:
Hg=(Hm-Hf)/2 (2)
where Hf is the thickness of the original film provided with no glass sheets.
The glass-mounted film 45A is thereafter disposed between the surface detecting sensor 60A and the emulsion layer detecting sensor. The sensor unit 50 is then shifted to a position at which the output of the signal PS of the surface detecting sensor 60A becomes maximum (see FIG. 14A) and the data regarding this shifted position is stored into a memory. The sensor unit 50 is again shifted from this position in the direction X 1 to a position at which the focus coincidence signal is transmitted from the TCL module 70 (see FIG. 14B). As described above, there will be obtained a distance x' between a position at which the surface detecting sensor 60A detects the surface of the glass-mount film 45A and a position shown in FIG. 14B at which the focus coincidence signal PC is transmitted from the TCL module 70 of the emulsion layer position detecting sensor, and the measured distance x 0 will be in accord with the thickness Hg of the glass sheet in a case where the front surface of the film 45A is on the lefthand side thereof as viewed in FIG. 14A or 14B.
On the other hand, in a case where the back surface of the film 45A is on the lefthand side thereof as shown in FIG. 15A or 15B, the focus coincidence signal PC will not be outputted from the TCL module 70 even if the point Po is shifted from the position (FIG. 15A) at which the output of the detected signal PS from the surface detecting sensor 60A reaches its peak to the left side surface of the film by the distance Hg corresponding to the thickness of the glass sheet in the direction X 2 . The focus coincidence signal PC will be transmitted (FIG. 15B) at a time when the sensor unit 50 is further shifted in the direction X 2 by the distance x 22 corresponding to the thickness of the base layer 47 of the film from the left side surface thereof to thereby detect the emulsion layer 46.
Accordingly, the surface (front or back) of the glass-mounted film can be discriminated by detecting the distance x' between the peak detecting position of the surface detecting sensor 60A and the focus coincidence signal PC outputting position. Namely, when the front surface of the film 45A is on the lefthand side thereof as shown in FIG. 14A or 14B, the following equation is established:
x'-Hg=0 (3)
When the back surface of the film 45A is on the lefthand side, the following equation is established:
x'-Hg=x.sub.22 (4)
It will of course be understood that the surface discrimination can be achieved with a slight allowance for the measured values. For example, the value (x'-Hg) can be compared with a value x 22 /3 for the surface discrimination.
With the modified embodiment of this invention described hereinabove, although it is assumed that the position P 1 and the position P 2 referred to hereinbefore completely coincide with each other, the positions P 1 and P 2 may become offset in an actual operation as shown in FIG. 16A or 16B for the reason caused by an error in an actual assembly of the machine parts of an optical system, an error in working operation of the parts, or a deformation thereof with time. In such a case, the present invention can be applied by preliminarily measuring the distance x 0 between the points P 1 and P 2 for the discrimination of the film surface. In addition, the thickness Hm of the glass-mounted film may be measured by a direct mechanical method or by the paired surface detecting sensors 60A and 60B arranged relative to each other. In this example, the thickness Hm of the glass-mount film is obtained by the following equation (5):
Hm=L.sub.1 -L.sub.2 (5)
where L 1 is a distance between a position P 12 at which the surface detecting sensor 60B transmits a signal PSB representing the maximum output and a position P 11 at which the surface detecting sensor 60A transmits signal PSA representing the maximum output, and L 2 is distance between a position at which the position P 1 coincides with one surface of the glass mount film 45A and a position at which the position P 2 coincides with the other surface of the film 45A. (see FIGS. 17A and 17B).
According to this invention, the surface (front or back) of the glass-mounted film can be accurately discriminated by preliminarily measuring the thickness of the glass sheets attached on both sides of the developed film.
As described hereinbefore, with one modified embodiment of this invention in conjunction with FIG. 6, although it is assumed that the point P 1 (maximum output position of the signal PS from the film surface detecting sensor 60) and the point P 2 (focusing position of the emulsion layer position detecting sensor) completely coincide with each other, in an actual operation, these points P 1 and P 2 may sometimes become offset because of errors caused in assembling or during the working time of the mechanical parts of an optical system or the deformation thereof with time. In such a case, it becomes necessary to compensate for the error of the measured distance x between the points P 1 and P 2 . A calibration method will be preferably applied to compensate for this error, which will be described hereinafter in conjunction with FIG. 6 showing the film surface discrimination apparatus according to one embodiment of this invention.
The apparatus shown in FIG. 6 generally comprises means for measuring the surface position of the film after being developed a means for measuring the emulsion layer on which a picture pattern of the film is formed, and circuit means for comparing the measured results from the surface position measuring means and the emulsion layer position measuring means and for discriminating the front or back surface of the film in accordance with the compared result.
In order to carry out the calibration method in use of the apparatus described above, the calibration member is arranged between the surface position measuring means and emulsion layer position measuring means, the calibration member being prepared by effecting a treatment of a picture easily focused by the emulsion layer position measuring means to a flat and non-deformable transparent base. An offset amount between the measured points obtained by the film surface position measuring means and the emulsion layer position measuring means is obtained by detecting one surface of the calibration member in the combined use of these measuring means. By inputting the obtained offset amount into the surface discriminating circuit, the circuit accurately discriminates the surface (front or back) of the film.
Regarding the offset amount between two points P 1 and P 2 , two cases will be considered, one being shown in FIG. 16A in which two points P 1 and P 2 are a certain distance apart, the other being shown in FIG. 16B in which two points overlap by a certain distance.
The case shown in FIG. 16A will be explained in connection with FIGS. 18A and 18B as follows. The calibration member 80 used for this invention is prepared as shown in FIGS. 18A and 18B by depositing or printing a picture or image 82 with a large contrast or density difference for easy focusing to one surface of a flat and non-deformable transparent base 81 (glass, for example). The calibration member 80 thus prepared is located between the film surface detecting sensor 60 and the emulsion layer position detecting sensor 50. The sensor unit 50 is shifted to a position at which the sensor 60 transmits the maximum output signal PS (FIG. 18A) and this position is stored in the memory. The sensor unit 50 is further moved from this position in the direction X 1 shown in FIG. 6 to a position at which the focus coincidence signal PC is transmitted from the TCL module 70 (FIG. 18B). Thus, the offset distance x 0 between the points P 1 and P 2 can be detected by obtaining the shifted distance of the sensor unit 50 from the position at which the film surface detecting sensor 60 detects the picture 82 of the calibration member 80 to the position at which the TCL module 70 of the emulsion layer position detecting sensor transmits the focus coincidence sigal PC. At this measuring time, it is necessary to make constant the direction of the picture 82 of the calibration member 80; that is, the measurement will have to be performed after confirming the fact that the picture 82 faces the point P 1 or P 2 .
In a case, as described above, where there exists the offset x 0 between the points P 1 and P 2 , the measured distance x, explained in conjunction with FIG. 11, includes the offset amount x 0 in a case shown in FIG. 10A. Accordingly, the surface (front or back) discriminating circuit can discriminate the surface of the film by subtracting the offset x 0 measured by the use of the calibration member 80 from the measured distance x. That is, when the following equation is established, it can be discriminated that the left side surface of the film is the front surface thereof as shown in FIG. 10A.
x-x.sub.0 =0 (6)
On the other hand, when the following equation is established, it can be discriminated that the left side surface of the film is the back surface thereof as shown in FIG. 10B.
x-x.sub.0 =x.sub.2 (7)
Furthermore, in a case where the points P 1 and P 2 overlap as shown in FIG. 16B, the offset distance x 0 ' between the points P 1 and P 2 can also measured by using the calibration member 80, and in the case shown in FIG. 16B, the surface (front of back) of the film can be discriminated by the following equations.
x+x.sub.0 '=0 (8)
x+x.sub.0 '=x.sub.2 (9)
It will of course be understood that the surface discrimination of this method can be achieved with a slight allowance for the measured values. For example, the value (x-x 0 ) or (x+x 0 ) can be compared with the value x 2 /2 for the surface discrimination.
According to this invention, the surface of the developed film can be further exactly discriminated by preliminarily arranging a calibration member even if errors in assembling or working machine parts or a deformation of the film with time occur.
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A method and apparatus for discriminating a surface of a developed film focuses a picture pattern on a film disposed at a reference position. One or two sensors are then located at focused positions of the picture pattern of the film when the front surface of the film is at the reference position and when the back surface of the film is at the reference position, respectively. The two resultant sensor outputs are then band-pass filtered to extract the portions of the outputs within a predetermined frequency range. The resultant outputs are then rectified and integrated and then compared by a comparator whose outputs is a first value when the front surface of the film is at the reference position and is a second different value when the back surface of the film is at a reference position.
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FIELD OF THE INVENTION
[0001] The present invention relates to compositions for application onto keratinous substrates such as hair and skin. In particular, the present invention relates to compositions containing a silicone-organic polymer hybrid compound and film forming polymers and to methods of caring for or imparting shape to or maintaining the shape of keratinous substrates contacted with said compositions.
BACKGROUND OF THE INVENTION
[0002] Consumers of cosmetic products actively seek out multi-functional, new products which are pleasing to the senses, both on application and in use, and which have innovative, interesting and/or pleasing textures, preferably without any sacrifice to functional performance. For example, for hair care and hair treatment products, one important functional element of such compositions is their ability to condition and style the hair without weighing it down. Many consumers seek hair care products which provide a light feel, are easy to apply, moisturize, and add shine to the hair. The resulting feel and texture of the product during the application process, in addition to the feel of the hair after the application are also important elements of such commodities.
[0003] Moreover, under high humidity conditions, hair tends to absorb moisture causing it to be less manageable, which makes it more difficult to shape and style hair. Frizzy hair is particularly prone to problems when exposed to higher humidity. Applying a coating, such as a moisture barrier or a film on the hair is known to help to keep moisture out of the hair allowing for more efficient hair shaping and maintenance of hair shape, even in extreme humidity conditions. In the area of skin care, applying a film or coating on skin which can help keep the skin moisturized and/or protect the skin from extreme weather conditions is highly desirable.
[0004] Traditional compositions on the cosmetic market appear in various forms. They can range anywhere from solutions, foams, gels, creams, waxes, mousses, sprays, serums, to aerosols and can impart a variety of levels of care and cosmeticity depending on the state of the hair and skin. However, these conventional cosmetic compositions contain emulsifying systems which may have limitations and may be less appealing to the consumer. For example, the use of silicone compounds in some of these compositions to achieve desirable shine or certain textures and feel may result in other limitations. Such limitations may include sticky or greasy products, irritation on the skin/scalp, a heavy or oily feel to the hair and skin, and the use of high levels of raw materials or additional ingredients to correct for the detrimental effects of other ingredients, leading to a costly product. Therefore, there is still a need to improve currently marketed commodities in order to provide the consumer with innovative formulations that present sensory, functionality and cost-effective perspectives on cosmetic products.
[0005] The formulation of hair spray compositions, especially aerosols, is another area where formulation challenges exist. Typically, such products contain at least one volatile organic compound (VOC) in order to impart certain attributes to the hair such as good styling hold. For essentially ecological reasons and governmental regulations in various countries, it is sought or even necessary to reduce the amount of volatile organic compounds (VOCs) present in the composition. To reduce the amount of VOC and to obtain a low-VOC aerosol device, the organic solvents, for instance ethanol and dimethyl ether, are partially replaced with water, and concomitantly, with other compounds such as silicone polymers and film forming polymers, which could pose more formulation challenges. In addition, even at very low to zero VOCs, problems related with moisture sensitivity of fully water-based products have been found to be problematic from the standpoints of moisture sensitivity and eco-toxicity depending on the polymer and regional regulations.
[0006] Thus, the ability to shape and/or maintain the shape of hair, and achieve a strong styling hold, good texture and good shine on hair, while providing a clean, natural and light-weight feel to the hair remain as additional areas for improvement, particularly in connection with certain type of polymers such as silicone-based polymers.
[0007] It is thus an object of the present invention to provide a cosmetic composition for use on keratinous substrates, such as skin and hair, which provides good texture and a clean, natural and light-weight feel on the substrates. When the keratinous substrate is hair, it is also an object of the present invention to provide a composition which can impart shape and/or maintain the shape of hair, provide a strong styling hold and good shine to the hair.
SUMMARY OF THE INVENTION
[0008] The present disclosure is directed to a composition comprising, in cosmetically acceptable carrier:
[0000] (a) at least one silicone-organic polymer hybrid compound;
(b) at least one nonionic film forming polymer;
(c) at least one amphoteric film forming polymer; and
(d) at least one neutralizer.
[0009] The present invention further relates to a method of imparting cosmetic benefits to keratinous substrates.
[0010] In certain embodiments, the present invention further relates to a method of imparting shape to hair or maintaining the shape of hair comprising applying the above-described composition to the hair.
[0011] It has been surprisingly and unexpectedly discovered that the application of the above-described compositions onto keratinous substrates, such as hair and skin, resulted in desirable and beneficial effects on the substrates, for example, excellent styling effects on hair, the ability to maintain the shape of hair, manageability of hair, good texture and a desirable shine/healthy look to hair. Additional advantages can be achieved with the use of the above-described composition on keratinous substrates such as smoothness, softness, and clean/natural and light-weight/non-greasy or non-oily feel. Furthermore, the compositions of the present disclosure can impart transfer/water resistant and humidity resistant properties to keratinous substrates.
[0012] The compositions of the present invention can be formulated as a spray product having a low content of volatile organic compounds.
DETAILED DESCRIPTION
[0013] The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “having” or “including” and not in the exclusive sense of “consisting only of”. The terms “a” and “the” as used herein are understood to encompass the plural as well as the singular.
[0014] Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients and/or reaction conditions are to be understood as being modified in all instances by the term “about,” meaning within 10% to 15% of the indicated number.
[0015] “Film former” or “film forming agent” or “film forming polymer” as used herein means a polymer or resin or material that leaves a film on the substrate to which it is applied, for example, after a solvent accompanying the film former has evaporated, dried, absorbed into and/or dissipated on the substrate.
[0016] “At least one” as used herein means one or more and thus includes individual components as well as mixtures/combinations.
[0017] “Substituted,” as used herein, means comprising at least one substituent. Non-limiting examples of substituents include atoms, such as oxygen atoms and nitrogen atoms, as well as functional groups, such as hydroxyl groups, ether groups, alkoxy groups, acyloxyalkyl groups, oxyalkylene groups, polyoxyalkylene groups, carboxylic acid groups, amine groups, acylamino groups, amide groups, halogen containing groups, ester groups, thiol groups, sulphonate groups, thiosulphate groups, siloxane groups, and polysiloxane groups. The substituent(s) may be further substituted.
Silicone-Organic Polymer Hybrid Compound
[0018] The at least one silicone-organic polymer hybrid compound of the present disclosure includes, but is not limited to, a silicone polyvinyl acetate compound.
[0019] The silicone-organic polymer hybrid compound of the present disclosure may also be chosen from a cross-linked anionic copolymer comprised of organic polymer blocks and silicone blocks, resulting in a multiblock polymer structure.
[0020] In particular, the silicone-organic polymer hybrid compound of the present disclosure may be chosen from cross-linked anionic copolymers comprising at least one cross-linked polysiloxane structural unit. Examples of these polymers have been described in the PCT publication, WO2011069786, published Jun. 16, 2011.
[0021] A particularly preferred silicone-organic polymer hybrid compound of the present disclosure is a compound having the INCI name of Crotonic Acid/Vinyl C8-12 Isoalkyl Esters/VA/Bis-Vinyldimethicone Crosspolymer which is a copolymer of Crotonic Acid, vinyl C8-12 isoalkyl esters and Vinyl Acetate crosslinked with bis-vinyldimethicone. This compound is commercially available from the company Wacker Chemie AG under the tradename Wacker Belsil® P1101 (may also be known under the tradename Wacker Belsil® P101). Crotonic Acid/Vinyl C8-12 Isoalkyl Esters/VA/Bis-Vinyldimethicone Crosspolymer is also known by the technical name of Crotonic Acid/Vinyl C8-12 Isoalkyl Esters/VA/divinyldimethicone Crosspolymer.
[0022] The at least one silicone-organic polymer hybrid compound is present in the composition of the present disclosure in an amount of from about 0.05 to about 20% by weight, such as from about 0.1 to about 10% by weight, or such as from about 0.5 to about 6% by weight, or such as from about 1 to about 3% by weight, including all ranges and subranges there-between, based on the total weight of the composition.
Nonionic Film Forming Polymer
[0023] The non-ionic fixing polymers which can be used according to the present disclosure are chosen, for example, from: vinylpyrrolidone homopolymers; copolymers of vinylpyrrolidone and of vinyl acetate; polyalkyloxazolines, such as the polyethyloxazolines provided by the company Polymer Chemistry Innovations under the names Aquazol® HP, and Aquzol® HVIS; vinyl acetate homopolymers, such as the product provided under the name UCAR™ 130 Latex Resin by the company Dow Chemical or the product provided under the name Ultrapure Polymer 2041-R 012 by the company Ultra Chemical, Inc.; copolymers of vinyl acetate and of acrylic ester, such as the product provided under the name Rhodopas AD 310 from Rhone-Poulenc; copolymers of vinyl acetate and of ethylene, such as the product provided under the name Dermacryl® LOR by the company Akzo Nobel; copolymers of vinyl acetate and of maleic ester, for example of dibutyl maleate, such as the product provided under the name Appretan MB Extra by the company Clariant; copolymers of polyethylene and of maleic anhydride; alkyl acrylate homopolymers and alkyl methacrylate homopolymers, such as the product provided under the name Micropearl RQ 750 by the company Matsumoto or the product provided under the name Luhydran® A 848 S by the company BASF; acrylic ester copolymers, such as, for example, copolymers of alkyl acrylates and of alkyl methacrylates, such as the product provided by the company Dow Chemical under the name Primal™ AC-261 K and the product provided by Evonik under the name Eudragit® NE 30 D, by the company BASF under the names Acronal® 601, Luhydran® R 8833 or 8845, or by the company Clariant under the names Appretan® N 9213 or N9212; copolymers of acrylonitrile and of a non-ionic monomer chosen, for example, from butadiene and alkyl (meth)acrylates; mention may be made of the products provided under the names Nipol LX 531 B by the company Nippon Zeon or those provided under the name CJ 0601 B by the company Rohm and Haas; polyurethanes, such as the products provided under the names Acrysol™ RM 1020 or Acrysol™ RM 2020 by the company Dow Chemical or the products Uraflex XP 401 UZ or Uraflex XP 402 UZ by the company DSM Resins; copolymers of alkyl acrylate and of urethane, such as the product 8538-33 by the company National Starch; polyamides, such as the product Estapor LO 11 provided by the company Rhone-Poulenc; and chemically modified or unmodified non-ionic guar gums.
[0024] The unmodified non-ionic guar gums are, for example, the products sold under the name Vidogum GH by the company Unipectine and under the name Jaguar® S by the company Rhodia. The modified non-ionic guar gums, which can be used according to the invention, are preferably modified by C1-C6 hydroxyalkyl groups. Mention may be made, by way of example, of the hydroxymethyl, hydroxyethyl, hydroxypropyl, and hydroxybutyl groups. These guar gums are well known in the state of the art and can, for example, be prepared by reacting the corresponding alkene oxides, such as, for example, propylene oxides, with guar gum, so as to obtain a guar gum modified by hydroxypropyl groups.
[0025] Other nonionic film forming polymers may be chosen from non-ionic guar gums optionally modified by hydroxyalkyl groups are, for example, sold under the trade names Jaguar® HP8, Jaguar® HP60, Jaguar® HP120, and Jaguar® HP 105 by the company Rhodia or under the name Galactasol™ 4H4FD2 by the company Ashland Specialty Ingredients.
[0026] The alkyl radicals of the non-ionic fixing polymers have from 1 to 6 carbon atoms, unless otherwise mentioned.
[0027] Other suitable examples of film forming polymers are fixing polymers of grafted silicone type comprising a polysiloxane portion and a portion composed of a non-silicone organic chain, one of the two portions constituting the main chain of the polymer and the other being grafted onto the said main chain. These polymers can be non-ionic.
[0028] Preferred nonionic film forming polymers of the present disclosure are chosen from vinylpyrrolidone homopolymers and copolymers of vinylpyrrolidone and of vinyl acetate. Vinylpyrrolidone homopolymers (INCI name: polyvinylpyrrolidone) are commercially available from Ashland Specialty Ingredients under the tradename PVP K. Copolymers of vinylpyrrolidone and of vinyl acetate (INCI name: VP/VA copolymer) are commercially available from BASF under the tradename Luviskol® VA.
[0029] The at least one nonionic film forming polymer is present in the composition of the present disclosure in an amount of from about 0.05 to about 15% by weight, such as from about 0.1 to about 10% by weight, and from about 0.5 to about 5% by weight, including all ranges and subranges there-between, based on the total weight of the composition.
Amphoteric Film Forming Polymer
[0030] The amphoteric film-forming polymers which can be used in accordance with the invention can be chosen from polymers containing units B and C distributed randomly in the polymer chain, in which B denotes a unit derived from a monomer containing at least one basic nitrogen atom and C denotes a unit derived from an acid monomer containing one or more carboxylic or sulphonic groups, or alternatively B and C can denote groups derived from carboxybetaine or sulphobetaine zwitterionic monomers;
[0031] B and C can also denote a cationic polymer chain containing primary, secondary, tertiary or quaternary amine groups, in which at least one of the amine groups bears a carboxylic or sulphonic group connected via a hydrocarbon radical or alternatively B and C form part of a chain of a polymer containing an α,β-dicarboxylic ethylene unit in which one of the carboxylic groups has been made to react with a polyamine containing one or more primary or secondary amine groups.
[0032] The amphoteric film-forming polymers corresponding to the definition given above which are more particularly preferred are chosen from the following polymers:
[0033] (1) polymers resulting from the copolymerization of a monomer derived from a vinyl compound bearing a carboxylic group such as, more particularly, acrylic acid, methacrylic acid, maleic acid, α-chloroacrylic acid, and a basic monomer derived from a substituted vinyl compound containing at least one basic atom, such as, more particularly, dialkylaminoalkyl methacrylates and acrylates, dialkylaminoalkylmethacrylamides and -acrylamides. Such compounds are described in U.S. Pat. No. 3,836,537.
[0034] (2) polymers containing units derived from:
[0035] a) at least one monomer chosen from acrylamides and methacrylamides substituted on the nitrogen with an alkyl radical,
[0036] b) at least one acidic comonomer containing one or more reactive carboxylic groups, and
[0037] c) at least one basic comonomer such as esters containing primary, secondary, tertiary and quaternary amine substituents of acrylic and methacrylic acids and the product of quaternization of dimethylaminoethyl methacrylate with dimethyl or diethyl sulphate.
[0038] The N-substituted acrylamides or methacrylamides which are more particularly preferred according to the invention are groups in which the alkyl radicals contain from 2 to 12 carbon atoms and more particularly N-ethylacrylamide, N-tert-butylacrylamide, N-tert-octylacrylamide, N-octylacrylamide, N-decylacrylamide, N-dodecylacrylamide and the corresponding methacrylamides.
[0039] The acidic comonomers are chosen more particularly from acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid and alkyl monoesters, having 1 to 4 carbon atoms, of maleic or fumaric acids or anhydrides.
[0040] The preferred basic comonomers are aminoethyl, butylaminoethyl, N,N′-dimethylaminoethyl and N-tert-butylaminoethyl methacrylates.
[0041] The copolymers whose CTFA (4th edition, 1991) name is octylacrylamide/acrylates/butylaminoethyl methacrylate copolymer such as the products sold under the name Amphomer® or Balance 47 (formerly Lovocryl 47) by the company Akzo Nobel are particularly used.
[0042] (3) crosslinked and alkylated polyamino amides partially or totally derived polyamino amides.
[0043] (4) polymers containing zwitterionic units of formula:
[0000]
[0044] in which R 11 denotes a polymerizable unsaturated group, such as an acrylate, methacrylate, acrylamide or methacrylamide group, y and z represent an integer from 1 to 3, R 12 and R 13 represent a hydrogen atom or methyl, ethyl or propyl, and R 14 and R 15 represent a hydrogen atom or an alkyl radical such that the sum of the carbon atoms in R 14 and R 15 does not exceed 10.
[0045] The polymers comprising such units can also contain units derived from non-zwitterionic monomers such as dimethyl or diethylaminoethyl acrylate or methacrylate or alkyl acrylates or methacrylates, acrylamides or methacrylamides or vinyl acetate:
[0046] By way of example, mention may be made of the copolymer of methyl methacrylate/dimethyl carboxymethylammonio methyl ethylmethacrylate.
[0047] (5) polymers derived from chitosan.
[0048] (6) Polymers derived from the N-carboxyalkylation of chitosan, such as N-carboxymethylchitosan or N-carboxybutylchitosan sold under the name “Evalsan” by the company Jan Dekker.
[0049] (7) Polymers corresponding to the general formula below are described, for example, in French patent 1,400,366:
[0000]
[0050] in which R 20 represents a hydrogen atom, a CH 3 O, CH 3 CH 2 O or phenyl radical, R 21 denotes hydrogen or a lower alkyl radical such as methyl or ethyl, R 22 denotes hydrogen or a lower alkyl radical such as methyl or ethyl, R 23 denotes a lower alkyl radical such as methyl or ethyl or a radical corresponding to the formula: —R 24 —N(R 22 ) 2 , R 24 representing a —CH 2 —CH 2 , —CH 2 —CH 2 —CH 2 — or —CH 2 —CH(CH 3 )— group, R 22 having the meanings mentioned above, as well as the higher homologues of these radicals and containing up to 6 carbon atoms.
[0051] (8) Amphoteric polymers of the type -D-X-D-X chosen from:
[0052] a) polymers obtained by the action of chloroacetic acid or sodium chloroacetate on compounds containing at least one unit of formula:
[0000] -D-X-D-X-D- (I)
[0053] where D denotes a radical
[0000]
[0054] and X denotes the symbol E or E′, E or E′, which may be identical or different, denotes a divalent radical which is an alkylene radical containing a straight or branched chain containing up to 7 carbon atoms in the main chain, which is unsubstituted or substituted with hydroxyl groups and which can contain, in addition to the oxygen, nitrogen and sulphur atoms, 1 to 3 aromatic and/or heterocyclic rings; the oxygen, nitrogen and sulphur atoms being present in the form of ether, thioether, sulphoxide, sulphone, sulphonium, alkylamine or alkenylamine groups, hydroxyl, benzylamine, amine oxide, quaternary ammonium, amide, imide, alcohol, ester and/or urethane groups.
[0055] b) Polymers of formula:
[0000] -D-X-D-X- (I′)
[0056] in which D denotes a radical
[0000]
[0057] and X denotes the symbol E or E′ and at least once E′; E having the meaning given above and E′ is a divalent radical which is an alkylene radical with a straight or branched chain having up to 7 carbon atoms in the main chain, which is unsubstituted or substituted with one or more hydroxyl radicals and containing one or more nitrogen atoms, the nitrogen atom being substituted with an alkyl chain which is optionally interrupted by an oxygen atom and necessarily containing one or more carboxyl functions or one or more hydroxyl functions and betainized by reaction with chloroacetic acid or sodium chloroacetate.
[0058] (9) (C1-05)alkyl vinyl ether/maleic anhydride copolymers, the maleic anhydride being partially modified by semiamidation with an N,N-dialkylaminoalkylamine such as N,N-dimethyl-aminopropylamine or by semiesterification with an N,N-dialkanolamine. These copolymers can also contain other vinyl comonomers such as vinylcaprolactam.
[0059] The amphoteric film-forming polymers which are particularly preferred according to the invention are those of family (3), such as the copolymers whose CTFA name is octylacrylamide/acrylates/butylaminoethyl methacrylate copolymer, such as the products sold under the names Amphomer® LV 71 by the company Akzo Nobel.
[0060] The at least one amphoteric film forming polymer is present in the composition of the present disclosure in an amount of from about 0.05 to about 5% by weight, such as from about 0.1 to about 4% by weight, and from about 0.5 to about 3% by weight, including all ranges and subranges there-between, based on the total weight of the composition.
Neutralizer
[0061] The compositions of the present disclosure also contain a neutralizer, which affects the pH of the composition so as to allow the silicone-organic polymer hybrid compound and/or the above described film forming polymers to remain solubilized. Representative examples of neutralizers useful for this purpose include AMP (aminomethyl propanol), AMPD (aminomethyl propanediol), TIPA (triisopropanol amine), Sodium/Potassium hydroxides, Dimethylsterarylamine, Dimethyl/tallowamine lysine, ornithine, arginine, glutamic and aspartic acid. The amount of neutralizer is selected on criteria that include the desired pH of the composition. Thus, the amount of neutralizer generally ranges from greater than 0 (e.g., about 0.01%) to about 3%, and in some embodiments from 0.05% to about 2%, by weight, based on the total weight of the composition.
Cosmetically Acceptable Carrier
[0062] The cosmetically acceptable carrier of the present disclosure comprises a solvent such as water or at least one cosmetically acceptable solvent chosen from organic solvents.
[0063] The cosmetically acceptable carrier of the present disclosure may also comprise mixtures of water and at least one cosmetically acceptable solvent chosen from organic solvents.
[0064] Suitable organic solvents may be chosen from non-volatile and nonvolatile organic solvents.
[0065] Suitable organic solvents are typically C1-C4 lower alcohols, polyols alcohols and polyol ethers. Examples of organic solvents include, but are not limited to, ethanol, isopropyl alcohol, benzyl alcohol and phenyl ethyl alcohol; glycols and glycol ethers, such as propylene glycol, hexylene glycol, ethylene glycol monomethyl, monoethyl or monobutyl ether, propylene glycol and its ethers, such as propylene glycol monomethyl ether, butylene glycol, dipropylene glycol, and also diethylene glycol alkyl ethers, such as diethylene glycol monoethyl ether and monobutyl ether; hydrocarbons such as straight chain hydrocarbons, mineral oil, isododecane, polybutene, hydrogenated polyisobutene, hydrogenated polydecene, polydecene, squalene, petrolatum and isoparaffins; and mixtures, thereof.
[0066] In certain embodiments, the cosmetically acceptable carrier of the present disclosure comprises volatile organic solvents/compounds.
[0067] Preferred examples of volatile organic solvents/compounds include C2 to C4 mono-alcohols, such as ethanol, polyols such as C2-C6 glycols e.g., propylene glycol, glycerol, and polyol ethers, acetone, propylene carbonate and benzyl alcohol.
[0068] The amount of the volatile organic solvent/compound can range from greater than 0 (e.g., about 0.01%) to about 55%, or from about 0.1% to about 20%, and in some embodiments from greater than 0 to about 10%, by weight, or from about 0.01% to about 6%, by weight, or from about 0.1% to about 3.5%, by weight, based on the total weight of the composition.
[0069] In certain embodiments, it is preferred that the amount of volatile organic solvent/compound does not exceed 55%.
[0070] In some embodiments, the cosmetically acceptable carrier in the compositions of the present disclosure contains water in the amount of about 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5% by weight or less, based on the total weight of the compositions. Additionally, the cosmetically acceptable carrier in the compositions of the present disclosure can contain water in the amount of from about 20% to about 95% by weight, or from about 50% to about 90% by weight, or from about 60% to about 80% by weight, based on the total weight of the compositions.
[0071] In other embodiments, the cosmetically acceptable carrier of the present disclosure comprises at least one cosmetically acceptable solvent chosen from organic solvents.
[0072] In yet some other embodiments, the cosmetically acceptable carrier of the present disclosure is substantially free of water.
[0073] Thus, the composition of the present disclosure can also be in the form of an anhydrous composition wherein the composition is substantially free of water. The term “substantially free of water” as it is used herein means that while it is preferred that no water be present in the composition, it is possible to have very small amounts of water in the compositions of the invention provided that these amounts do not materially affect at least one, preferably most, of the advantageous properties of the compositions of the invention. In particular, “substantially free of water” means that water can be present in the composition in an amount of less than about 2% by weight, or less than about 1% by weight, or less than about 0.5% by weight, or less than about 0.05% by weight of the total weight of the composition of water.
[0074] The term “water” as used in the term “substantially free of water” herein refers to water that is included as a separate ingredient in the compositions of the present disclosure and does not refer to water that may accompany one or more ingredients of a raw material that is added into the composition.
[0075] The compositions described above are useful for application onto keratinous substrates such as hair and skin.
[0076] Thus, the compositions of the present disclosure can be made into various cosmetic products such hair care products, skin care products and make up products.
[0077] Representative types of hair care compositions, including hair cosmetic and styling compositions, of the present invention include compositions for shaping the hair, maintaining the shape of the hair, styling products (e.g., gels, creams, milks, pastes, waxes, ointments, serums, foams, hair lotions, mousses, pump-sprays, non-aerosol sprays and aerosol sprays), pre-treatments and post-treatments for color protection, conditioning or protection from heat damage, leave-in hair treatments, rinse-off hair treatments, combination shampoo/styling compositions and hair volumizing compositions.
[0078] The compositions of the present disclosure can be in the form of an aqueous composition or an emulsion, such as a lotion or cream.
[0079] In one embodiment, the composition of the present disclosure is in the form of a non-aerosol spray, preferably containing a volatile organic solvent/compound.
[0080] In another embodiment, the composition of the present disclosure is in the form of a wax or a paste.
[0081] In yet another embodiment, the composition of the present disclosure is in the form of an aerosol spray, comprising a propellant.
[0082] Representative examples of propellants include C, 3 to C, 5 alkanes such as n-butane, isobutane, and propane, dimethyl ether (available commercially from Harp Int'l under the tradename HARP DME), C2-05 halogenated hydrocarbons, e.g., 1,1-difluoroethane (available commercially from DuPont under the tradename DYMEL 152a), difluoroethane, chlorodifluoroethane, chlorodifluoromethane, air, nitrogen, carbon dioxide, and mixtures thereof. The amount of the propellant can range from about 3 to about 90%, and in some embodiments from about 3 to about 60%, by weight, or such as from about 3 to about 20% by weight, or such as from about 3 to about 10% by weight, or such as from about 3 to about 6%, by weight based on the total weight of the composition.
[0083] Accordingly, the compositions of the present disclosure may contain at least one auxiliary ingredient, which as those skilled in the cosmetics art will appreciate, is chosen based on several criteria, including for example, the type of product and its intended use and effect, compatibility with the other ingredients, and aesthetic appeal. Representative types of such additional ingredients include rheology modifiers (also known as gelling agents or thickeners), nonionic surfactants, lipophilic compounds such as oils and waxes, and hair and skin active ingredients. Examples of these ingredients are described herein.
Rheology Modifiers
[0084] Broadly, the rheology modifier(s) that may be useful in the practice of the present invention include those conventionally used in cosmetics such as polymers of natural origin and synthetic polymers.
[0085] Representative rheology-modifying agents that may be used in the practice of the present invention include nonionic, anionic, cationic, and amphoteric polymers, and other rheology modifiers such as cellulose-based thickeners (e.g., hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, cationic cellulose ether derivatives, quaternized cellulose derivatives, etc.), guar gum and its derivatives (e.g., hydroxypropyl guar, cationic guar derivatives, etc.), gums such as gums of microbial origin (e.g., xanthan gum, scleroglucan gum, etc.), and gums derived from plant exudates (e.g., gum arabic, ghatti gum, karaya gum, gum tragacanth, carrageenan gum, agar gum and carob gum), pectins, alginates, and starches, crosslinked homopolymers of acrylic acid or of acrylamidopropane-sulfonic acid, associative polymers, non-associative thickening polymers, and water-soluble thickening polymers.
[0086] In some embodiments, the rheology-modifying agent includes a polymer chosen from nonionic, anionic, cationic and amphoteric amphiphilic polymers.
[0087] The rheology-modifying agents may also be chosen from associative celluloses include quaternized cationic celluloses and quaternized cationic hydroxyethylcelluloses modified by groups containing at least one hydrophobic chain, such as alkyl, arylalkyl or alkylaryl groups containing at least 8 carbon atoms, and mixtures thereof.
[0088] The alkyl radicals carried by the above quaternized celluloses or hydroxyethylcelluloses may, in various embodiments, comprise from 8 to 30 carbon atoms. The aryl radicals may, for example, denote the phenyl, benzyl, naphthyl or anthryl groups. Representative examples of quaternized alkylhydroxy-ethylcelluloses containing a C8-C30 hydrophobic chain include the products Quatrisoft LM 200®, Quatrisoft LM-X 529-18-A®, Quatrisoft LM-X 529-18B® (C12 alkyl) and Quatrisoft LM-X 529-8® (Ci8 alkyl) sold by Amerchol and the products Crodacel QM®, Crodacel QL® (C12 alkyl) and Crodacel QS® (Ci8 alkyl) sold by Croda.
[0089] Representative examples of nonionic cellulose derivatives include hydroxyethylcelluloses modified by groups comprising at least one hydrophobic chain, such as alkyl, arylalkyl or alkylaryl groups, or their blends, and in which the alkyl groups are, for example, C8-C22 alkyl groups, such as the product Natrosol Plus Grade 330 CS® (C16 alkyls) sold by Aqualon or the product Bermocoll EHM 100® sold by Berol Nobel.
[0090] Representative examples of cellulose derivatives modified by alkylphenyl polyalkylene glycol ether groups include the product Amercell Polymer HM-1500® sold by Amerchol.
[0091] The rheology-modifying agent is typically present in an amount ranging from about 0.01% to about 10% by weight, in some embodiments from about 0.1% to about 5% by weight, based on the total weight of the composition.
[0092] The compositions of the present disclosure may further comprise compounds such as gellifying and viscosity modifying agents which may aid in improving the viscosity of the compositions.
Nonionic Surfactants
[0093] The compositions of the present disclosure can further comprise at least one nonionic surfactant.
[0094] Non-limiting examples of nonionic surfactants includes alkoxylated derivatives of the following: fatty alcohols, alkyl phenols, fatty acids, fatty acid esters and fatty acid amides, wherein the alkyl chain is in the C12-50 range, typically in the C16-40 range, more typically in the C24 to C40 range, and having from about 1 to about 110 alkoxy groups. The alkoxy groups are selected from the group consisting of C2-C6 oxides and their mixtures, with ethylene oxide, propylene oxide, and their mixtures being the typical alkoxides. The alkyl chain may be linear, branched, saturated, or unsaturated. Of these alkoxylated non-ionic surfactants, the alkoxylated alcohols are typical, and the ethoxylated alcohols and propoxylated alcohols are more typical. The alkoxylated alcohols may be used alone or in mixtures with those alkoxylated materials disclosed herein-above.
[0095] Commercially available nonionic surfactants are Brij® nonionic surfactants from Croda, Inc., Edison, N.J. Typically, Brij® is the condensation products of aliphatic alcohols with from about 1 to about 54 moles of ethylene oxide, the alkyl chain of the alcohol being typically a linear chain and having from about 8 to about 22 carbon atoms, for example, Brij® 72 (i.e., Steareth-2) and Brij® 76 (i.e., Steareth-10).
[0096] Also useful herein as nonionic surfactants are alkyl glycosides, which are the condensation products of long chain alcohols, which are the condensation products of long chain alcohols, e.g. C8-C30 alcohols, with sugar or starch polymers. These compounds can be represented by the formula (S)n-O—R wherein S is a sugar moiety such as glucose, fructose, mannose, galactose, and the like; n is an integer of from about 1 to about 1000, and R is a C8-C30 alkyl group. Examples of long chain alcohols from which the alkyl group can be derived include decyl alcohol, cetyl alcohol, stearyl alcohol, lauryl alcohol, myristyl alcohol, oleyl alcohol, and the like. Preferred examples of these surfactants are alkyl polyglucosides wherein S is a glucose moiety, R is a C8-C20 alkyl group, and n is an integer of from about 1 to about 9. Commercially available examples of these surfactants include decyl polyglucoside (available as APG® 325 CS) and lauryl polyglucoside (available as APG® 600CS and 625 CS), all the above-identified polyglucosides APG® are available from Cognis, Ambler, Pa. Also useful herein sucrose ester surfactants such as sucrose cocoate and sucrose laurate.
[0097] Other nonionic surfactants suitable for use in the present invention are glyceryl esters and polyglyceryl esters, including but not limited to, glyceryl monoesters, typically glyceryl monoesters of C16-C22 saturated, unsaturated and branched chain fatty acids such as glyceryl oleate, glyceryl monostearate, glyceryl monoisostearate, glyceryl monopalmitate, glyceryl monobehenate, and mixtures thereof, and polyglyceryl esters of C16-C22 saturated, unsaturated and branched chain fatty acids, such as polyglyceryl-4 isostearate, polyglyceryl-oleate, polyglyceryl-2 sesquioleate, triglyceryl diisostearate, diglyceryl monooleate, tetraglyceryl monooleate, and mixtures thereof.
[0098] Also useful herein as nonionic surfactants are sorbitan esters. Preferable are sorbitan esters of C16-C22 saturated, unsaturated and branched chain fatty acids. Because of the manner in which they are typically manufactured, these sorbitan esters usually comprise mixtures of mono-, di-, tri-, etc. esters. Representative examples of suitable sorbitan esters include sorbitan monooleate (e.g., SPAN® 80), sorbitan sesquioleate (e.g., Arlacel® 83 from Croda, Inc., Edison, N.J.), sorbitan monoisostearate (e.g., CRILL® 6 from Croda, Inc., Edison, N.J.), sorbitan stearates (e.g., SPAN® 60), sorbitan trioleate (e.g., SPAN® 85), sorbitan tristearate (e.g., SPAN® 65), sorbitan dipalmitates (e.g., SPAN® 40), and sorbitan isostearate. Sorbitan monoisostearate and sorbitan sesquioleate are particularly preferred emulsifiers for use in the present invention.
[0099] Also suitable for use as nonionic surfactants are alkoxylated derivatives of glyceryl esters, sorbitan esters, and alkyl polyglycosides, wherein the alkoxy groups are selected from the group consisting of C2-C6 oxides and their mixtures, with ethoxylated or propoxylated derivatives of these materials being typical. Nonlimiting examples of commercially available ethoxylated materials include TWEEN® (ethoxylated sorbitan mono-, di- and/or tri-esters of C12 to C18 fatty acids with an average degree of ethoxylation of from about 2 to 20).
[0100] One type of preferred nonionic surfactants include alkoxylated alcohols such as a polyethylene derivative of hydrogenated castor oil, for example, PEG-40 hydrogenated castor oil, commercially available from the company Cognis (BASF) under the tradename Eumulgin® HRE 40 or Cremophor® CO 40.
[0101] The at least one nonionic surfactant is typically present in an amount from about 0.5 by weight to about 30% by weight, typically in an amount from about 1 by weight to about 20% by weight and more typically from about 0.5 by weight to 10% by weight, including all ranges and subranges there-between, based on the total weight of the composition of the present disclosure.
Lipophilic Compounds
[0102] The compositions of the present disclosure can further comprise at least one lipophilic compound which can be chosen from oils, fatty esters, hydrocarbon oils, waxes, fatty acids and salts thereof, fatty alcohols, lipophilic vitamins and esters thereof, organic sunscreens, phospholipids, and mixtures thereof.
[0103] Oils that may be suitable for use in the present invention include both volatile and nonvolatile oils. The volatile or nonvolatile oils are typically selected from hydrocarbon-based oils, silicone oils, and fluoro oils. The term “hydrocarbon-based oil” refers to oil mainly containing hydrogen and carbon atoms and possibly oxygen, nitrogen, sulfur and/or phosphorus atoms.
[0104] Non-limiting examples of oils include plant oils such as olive oil, avocado oil, coconut oil, safflower oil, almond oil, castor oil, jojoba oil, peanut oil, sesame oil, hazelnut oil, sunflower oil, apricot kernel oil, grapeseed oil, palm oil, argan oil, squalane and pracaxi oil.
[0105] Non-limiting examples of synthetic oils and hydrocarbon oils include mineral oil, petrolatum, and C 10 -C 40 hydrocarbons which may be aliphatic (with a straight, branched or cyclic chain), aromatic, arylaliphatic such as paraffins, iso-paraffins, isododecanes, aromatic hydrocarbons, and mixtures thereof.
[0106] Non-limiting examples of waxes include paraffin wax, beeswax, candelilla wax, carnauba wax, jasmine wax, jojoba wax and mimosa wax.
[0107] Suitable fatty acids include those containing from 8 to 30, preferably from 12 to 24 carbon atoms, and carboxylate salts of fatty acids. The sodium, potassium, ammonium, calcium and magnesium carboxylates of fatty acids listed are typical examples of the carboxylate salts of the fatty acids.
[0108] Non-limiting preferred examples of fatty alcohols include compounds of formula:
[0000] R—OH
[0109] where R represents a hydrocarbon radical containing at least three carbon atoms, preferably from 8 to 30, more preferably from 12 to 24 carbon atoms, and which may be linear or branched, acyclic or cyclic, saturated or unsaturated, aliphatic or aromatic, substituted or unsubstituted. Typically, R is a linear or branched, acyclic alkyl or alkenyl group or an alkyl phenyl group.
[0110] Non-limiting preferred fatty esters include esters formed from fatty acids and C 1-10 alcohols and esters formed from the fatty alcohols as defined hereabove and C 1-10 carboxylic acids.
[0111] In addition, non-limiting specific examples of lipophilic compounds include isopropyl palmitate, capric/caprylic triglyceride, isodecyl neopentanoate, polylsobutylene, Phloretin, Ellagic acid, Vitamin D, Vitamin E, Vitamin E Acetate, Vitamin A, Vitamin A Palmitate, 2-oleamido-1,3-octadecanediol, octyl methoxycinnamate, octyl salicylate, 18-Methyleicosanoic acid, and mixtures thereof. Other types of lipophiles include organic sunscreens, phospholipids, other water-insoluble vitamins, and other natural and synthetic oils.
[0112] Representative examples of volatile hydrocarbon-based oils include oils containing from 8 to 16 carbon atoms, and especially branched C8-C16 alkanes (also known as isoparaffins), for instance isododecane (also known as 2,2,4,4,6-pentamethylheptane), isodecane and isohexadecane.
[0113] Examples of nonvolatile silicone oils that may be useful in the present invention include nonvolatile polydimethylsiloxanes (PDMS), polydimethylsiloxanes comprising alkyl or alkoxy groups that are pendent and/or at the end of a silicone chain, these groups each containing from 2 to 24 carbon atoms, phenyl silicones, for instance phenyl trimethicones, phenyl dimethicones, phenyl trimethylsiloxy diphenylsiloxanes, diphenyl dimethicones, diphenyl methyldiphenyl trisiloxanes and 2-phenylethyl trimethylsiloxysilicates, and dimethicones or phenyltrimethicones with a viscosity of less than or equal to 100 cSt.
[0114] Representative examples of volatile silicone oils that may be useful in the present invention include volatile linear or cyclic silicone oils, especially those with a viscosity ÿ centistokes (8×10-6 m 2/s) and especially containing from 2 to 10 silicon atoms and in particular from 2 to 7 silicon atoms, these silicones optionally comprising alkyl or alkoxy groups containing from 1 to 10 carbon atoms. Specific examples include dimethicones with a viscosity of 5 and 6 cSt, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, heptamethylhexyltrisiloxane, heptamethyloctyltrisiloxane, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane and dodecamethylpentasiloxane, and mixtures thereof.
[0115] Representative examples of volatile fluoro oils that may be suitable for use in the present invention include nonafluoromethoxybutane and perfluoro-methylcyclopentane.
[0116] According to one embodiment, the at least one lipophilic compound is chosen from plant oils, hydrocarbon oils, synthetic oils, fatty acids having at least 12 carbon atoms, fatty esters and mixtures thereof.
[0117] According to another embodiment, the at least one lipophilic compound comprises fragrance oils.
[0118] The at least one lipophilic compound is present in the composition of the present disclosure in an amount of from about 0.1 to about 20% by weight, such as from about 0.3 to about 10% by weight, and from about 0.5 to about 5% by weight, including all ranges and subranges there-between, based on the total weight of the composition.
[0119] As skin and hair active agents that may be used in the composition of the present disclosure, examples that may be mentioned include moisturizers, for example, protein hydrolysates and polyols such as glycerol, glycols, for instance polyethylene glycols, and sugar derivatives; natural and plant extracts; anti-inflammatory agents; antioxidants; anti-wrinkle agents; procyannidol oligomers; vitamins, for instancevitamin A (retinol), vitamin C (ascorbic acid), vitamin E (tocopherol), vitamin B5 (panthenol), vitamin B3 (niacinamide), derivatives of these vitamins (especially esters) and mixtures thereof; urea; caffeine; depigmenting agents such as kojic acid, hydroquinone and caffeic acid; salicylic acid and its derivatives; α-hydroxy acids such as lactic acid and glycolic acid and derivatives thereof; β-hydroxy acids, α-keto acids, β-keto acids, retinoids such as carotenoids and vitamin A derivatives; sunscreens; self-tanning agents; hydrocortisone; melatonin; algal, fungal, plant, yeast or bacterial extracts; enzymes; DHEA and its derivatives and metabolites; antibacterial active agents, for instance 2,4,4′-trichloro-2′-hydroxydi-phenyl ether (or Triclosan), 3,4,4′-trichloro-carbanilide (or Triclocarban); mattifying agents and mixtures thereof.
[0120] Non-limiting examples of sunscreens include benzophenones, bornelone, butyl PABA, cinnamidopropyl trimethyl ammonium chloride, disodium distryrylbiphenyl disulfonate, PABA, potassium methoxycinnamate, butyl methoxydibenzoylmethane, octyl methoxycinnamate, oxybenzone, octocrylene, octyl salicylate, phenylbenzimidazole sulfonic acid, ethyl hydroxypropyl aminobenzoate, menthyl anthranilate, aminobenzoic acid, cinoxate, diethanolamine methoxycinnamate, glyceryl aminobenzoate, titanium dioxide, zinc oxide, oxybenzone, ethylhexyl dimethyl PABA, red petrolatum, and mixtures thereof.
[0121] Non-limiting examples of preservatives include polyvinyl alcohol, phenoxyethanol, benzyl alcohol, methyl paraben, propyl paraben and mixtures thereof.
[0122] Non-limiting examples of pH adjusting agents include potassium acetate, sodium carbonate, sodium hydroxide, phosphoric acid, succinic acid, sodium citrate, citric acid, boric acid, lactic acid, sodium hydrogen carbonate and mixtures thereof.
[0123] Yet other examples of auxiliary ingredients that may be present in the inventive compositions include fragrances, preservatives, colorants, glitter, fillers/powders, buffers, chelators (such as EDTA and salts thereof, particularly sodium and potassium salts), reducing agents, plasticizers, softeners, antifoaming agents, inorganic colloids, peptizing agents, pearlescent agents, penetrants, opacifying agents, silicones, and any other additive or adjuvant conventionally used in cosmetic compositions intended to be applied to the hair. The compositions may further contain polymers other than the silicone-organic polymer hybrid compound of the invention, provided that they are compatible with the other ingredients therein.
[0124] The at least one auxiliary ingredient is present in the composition in a preferred amount of from about 0.001 to about 50% and more preferably from about 0.01 to about 20% by weight, based on the total weight of the composition.
[0125] One embodiment of the present disclosure is a cosmetic composition comprising, in a cosmetically acceptable carrier, at least one silicone-organic polymer hybrid compound, at least one nonionic film forming polymer, at least one amphoteric film forming polymer, and at least one neutralizer.
[0126] In one embodiment, the composition of the present disclosure is a composition for shaping the hair and/or maintaining the shape of hair, such as a styling composition.
[0127] In other embodiments, the composition of the present disclosure additionally contains a volatile organic solvent/compound.
[0128] In one preferred embodiment the composition of the present disclosure is in the form of a spray composition.
[0129] In other embodiments the composition of the present disclosure contains a propellant.
[0130] In yet other embodiments the composition of the present disclosure does not contain a propellant.
[0131] In one embodiment, the composition of the present disclosure does not contain an anionic polymer other than the silicone-organic polymer hybrid compound of the present disclosure.
[0132] In other embodiments, the composition of the present disclosure is a composition for the care of skin and/or hair.
Method of Use
[0133] The method or process of using the compositions of the present disclosure will depend on the keratinous substrate being targeted and, consequently, the specific ingredients contained in the composition used to effectuate the treatment. One of ordinary skill in the art will easily be able to determine these variables.
[0134] An embodiment of the present invention is a method of caring for a keratinous substrate such as skin or hair.
[0135] A preferred embodiment of the present invention is a method of imparting shape to or maintaining the shape of hair comprising applying onto the hair, the above-described composition.
[0136] According to at least one embodiment, such a method comprises applying to the hair, an effective amount of the composition.
[0137] An effective amount of the composition, typically from about 0.1 gram to about 50 grams, preferably from about 0.5 gram to about 20 grams of the composition. Application to the hair typically includes working the composition through the hair.
[0138] The compositions may be applied to wet or dry hair, before or after shaping. They may be used in a non-rinse fashion in order to impart or maintain the shape of the hair. In some other embodiments, the composition may be rinsed from the hair. In some embodiments, following application of the composition, the hair is dried (e.g., air or blow dried), or dried in conjunction with the use of shaping tools and/or heating tools such as a hot iron, e.g., flat iron or curling iron, blow dryer, and hood dryer. Other shaping tools may be chosen from combs and brushes.
[0139] Embodiments of the present invention will now be described in terms of the following non-limiting working examples. Unless indicated to the contrary, all parts are by weight.
[0140] The following examples are for illustrative purposes only and are not intended to limit the scope of the claims.
EXAMPLES
Example 1
Formulation Examples, Table 1
[0141]
[0000]
Formula A
Formula B
Inventive
Comparative
INCI US
formula
formula
CROTONIC ACID/VINYL C8-12
2.5
2.5
ISOALKYL ESTERS/VA/BIS-
VINYLDIMETHICONE CROSSPOLYMER
VP/VA COPOLYMER
1.75
—
OCTYLACRYLAMIDE/ACRYLATES/
2.18
—
BUTYLAMINOETHYL METHACRYLATE
COPOLYMER
AMINOMETHYL PROPANOL
0.62
0.62
PEG-40 HYDROGENATED CASTOR OIL
1.5
1.5
FRAGRANCE, TOCOPHEROL,
0.80
0.80
PRESERVATIVES
XYLOSE
0.1
0.1
ALCOHOL DENAT.
6.00
6.00
WATER
QS 100
QS 100
Procedure of Making:
[0000]
1. In side phase A, water was added to a suitably sized vessel.
2. Aminomethyl Propanol, Octylacrylamide/acrylates/butylaminoethyl methacrylate copolymer, and VP/VA Copolymer were added and mixed into the water to form a uniform mixture.
3. Xylose was added and mixed into the mixture.
4. Preservatives were added and mixed into the mixture.
5. In side phase B, PEG-40 Hydrogenated Castor Oil was melted to 45-50° C. Fragrance was added and mixed until uniformity. Phase B was added to phase A.
6. Alcohol was added to the mixture of phases A and B and mixed until uniformity.
7. In side phase C, Crotonic Acid/Vinyl C8-12 Isoalkyl Esters/VA/Bis-vinyldimethicone crosspolymer was combined with Aminomethyl Propanol and mixed until uniform. Side phase C was added to the combined phases A and B.
[0149] The preparation of Formula B did not require step 2 in the procedure above.
[0150] The formula examples above were formulated as spray compositions which were applied onto hair swatches according to the following procedure of cosmetically treating/coating and shaping the hair:
[0151] One-inch thick hair swatches were prepared from European hair (commercially available), naturally wavy hair.
[0152] Five sprays of each formula to be tested were applied to a designated swatch resulting in coated swatches; five sprays amounted to about 0.6 grams of a test formula.
[0153] Each coated swatch was combed through three times.
[0154] Each swatch was then subjected to up to seven passes of a flat iron set to 410° F.
[0155] Each swatch was then combed through three times.
[0156] Following the procedure above, although all the test swatches had a smooth feel and noticeable shine, the swatches coated with the inventive formula (A) were noticeably more texturized (gave a feeling of more hold and form to the hair upon touching the hair) and their shapes were better maintained (better styling hold). In addition, it took only three passes of the flat iron to effectively smooth out the hair coated with formula A whereas it took seven passes of the flat iron to effectively smooth out the hair coated with the comparative formula (B). Thus, the use of the inventive formula resulted in a more time efficient process of styling/shaping the hair. In addition, the presence of the additional film forming polymers, Octylacrylamide/acrylates/butylaminoethyl methacrylate copolymer, and VP/VA Copolymer, did not weigh the hair down nor adversely affect the performance of the silicone-organic polymer hybrid compound.
Example 2
Inventive Formulas without Alcohol
[0157] The formula A in example 1 was also formulated as a paste and as a wax (containing additional wax ingredients) without adding alcohol as a separate ingredient.
[0158] The inventive wax formula was applied onto the hair of one half side of a mannequin head and a comparative formula which did not contain the Crotonic Acid/Vinyl C8-12 Isoalkyl Esters/VA/Bis-vinyldimethicone crosspolymer was applied to the hair of the other half side of the mannequin head.
[0159] The inventive paste formula was similarly applied onto the hair of one half side of a mannequin head and a comparative formula which did not contain the Crotonic Acid/Vinyl C8-12 Isoalkyl Esters/VA/Bis-vinyldimethicone crosspolymer was applied to the hair of the other half side of the mannequin head.
[0160] The hair treated with the inventive wax and paste formulas resulted in a more finished look to the hair, disciplined ends of the hair (more hold and control), smoother feel, and more shine.
Example 3
Comparative Examples, Table 2
[0161]
[0000]
Formula F
Formula
Formula
Formula
(inventive
C
D
E
composition)
INCI name/ingredients
% wt
% wt
% wt
% wt
CROTONIC ACID/VINYL C8-12
2.5
2.5
2.5
2.5
ISOALKYL ESTERS/VA/BIS-
VINYLDIMETHICONE
CROSSPOLYMER
ALCOHOL DENAT.
3.5
3.5
3.5
3.5
OCTYLACRYLAMIDE/ACRYLATES/
—
2.43
—
1.21
BUTYLAMINOETHYL
METHACRYLATE COPOLYMER
VP/VA COPOLYMER
—
—
2.5
1.25
AMINOMETHYL PROPANOL (for
0.13
0.66
0.01
0.4
neutralization of the
silicone-organic polymer
hybrid compound)
WATER
QS 100
QS 100
QS 100
QS 100
[0162] Formulas C to F in Table 2 were made according to the procedure of making in example 1 above.
[0163] The formula examples above were formulated as spray compositions which were applied onto hair swatches according to the following procedure of cosmetically treating/coating and shaping the hair:
[0164] One half centimeter-inch thick and 8 inch long hair swatches were prepared.
[0165] Three sprays of each formula to be tested were applied to designated swatches resulting in coated swatches; three sprays amounted to about 0.43±0.03 grams of a test formula.
[0166] Each coated swatch was combed through three times.
[0167] Each swatch was then curled using a Conair Instant Heat curling iron at a setting of 17, holding the hair curled along the curling iron for six seconds per curling step.
[0168] Following the procedure above, the swatch coated with the inventive composition, formula F, exhibited the most discipline and compact curl, that is, no frayed ends, no static-induced individualized hair fibers, compared to those coated with the other test formulas. Moreover, the swatch coated with formula F was just as smooth and silky as the swatch coated with formula C (which did not contain the film forming polymers) and more smooth and silky than the swatch coated with formula D which indicates that the presence of the amphoteric and nonionic film forming polymers did not make the hair undesirably stiff nor did their presence result in a brittle or hard film on the hair. Thus, these film forming polymers did not negatively impact the performance of the silicone-organic polymer hybrid compound but instead, significantly contributed to the efficacious performance of the inventive composition. Overall, the combination of polymers in the inventive composition boosted the hold level of each of the polymers and provided compactness and discipline to the curled hair, without sacrificing the suppleness and bounce of the curl and the smooth feel attributed to the silicone-organic polymer hybrid compound.
[0169] The foregoing description illustrates and describes the present disclosure. Additionally, the disclosure shows and describes only the preferred embodiments of the disclosure, but, as mentioned above, it is to be understood that it is capable of changes or modifications within the scope of the concept as expressed herein, commensurate with the above teachings and/or skill or knowledge of the relevant art. The embodiments described hereinabove are further intended to explain best modes known of practicing the invention and to enable others skilled in the art to utilize the disclosure in such, or other, embodiments and with the various modification required by the particular applications or uses disclosed herein. Accordingly, the description is not intended to limit the invention to the form disclosed herein. Also, it is intended that the appended claims be construed to include alternative embodiments.
[0170] All publications, patents and patent applications cited in this specification are herein incorporated by reference, and for any and all purposes, as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference. In the case of inconsistencies, the present disclosure will prevail.
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The present invention is directed towards a composition comprising, in a cosmetically acceptable carrier, at least one silicone-organic polymer hybrid compound; at least one nonionic film forming polymer; at least one amphoteric film forming polymer; and a neutralizer. The present invention also relates to methods for imparting shape to or maintaining the shape of hair wherein the composition provides style memory, strong hold and good shine, while at the same time, providing smoothness and a natural feel to the hair.
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FIELD OF THE INVENTION
The invention relates to radio frequency identification, and more particular to a system for monitoring the presence of objects.
BACKGROUND OF THE INVENTION
People often carry important items with them, such as passports, plane tickets, watches, medicine, eyeglass cases, security cards, laptop computers, car keys, AC adapter plugs, cameras, cell phones, or even gold pens. When traveling, either long distances or simply to a business meeting, people often pack and unpack these items, or carry the items in more than one bag. These items are therefore sometimes left behind when leaving taxis, packing for vacation, checking out of a hotel, or leaving a business meeting. Even if not left behind, a person must worry about ensuring that all important items are with him or her.
Several systems exist for using radio frequency identification (RFID) for tracking or identifying objects. RFID kits can be purchased, and RFID tags placed on items. The RFID tag can then be identified using a scanner. This presents an opportunity for a system to track personal items automatically, without having to manually search through bags or perform mental checklists.
One system (described in New Scientist, “Tags to Banish Forgetfulness”, Aug. 14, 2004, p. 19) proposes installing an RFID detector in a wrist watch, and an RFID interrogator in a separate device near a doorway. The RFID interrogator transmits signals to cause RFID tags to transmit their RFIDs. The RFIDs are detected by the RFID detector in the person's watch. If RFID tags are placed on important items carried by the person, then as the person passes the RFID interrogator the RFID detector within the watch will detect any RFIDs which are missing, and notify the person which if any personal items are absent.
This system requires an external and separate interrogator because of the small size of a watches and the size constraints on RFID interrogators. The system is also passive as far as the user is concerned, because the user is only alerted to missing items when passing fixed RFID interrogators placed at strategic locations. And while useful at notifying the user of missing items, the system cannot assist in locating the missing item or indicating where the item was last detected to narrow the range of possible locations when searching for the item.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a method is provided for detecting the presence of items labeled with radio frequency identification (RFID) tags. A current list of items is stored. In response to a query by a user, detection of the RFID tags of each item in the current list is attempted. For items whose RFID tag is not within detection range, the user is notified that the item is missing. In one embodiment, an item list is stored, the list having at least one record, each record corresponding to an item and storing a name of the item and the RFID of the RFID tag of the item. Travel lists are generated, comprising RFIDs from the item list. One of the travel lists is designated as the current list. The travel list to be designated as the current list may be designated by the user. Alternatively, the current list may be designated based on a current location, each travel list being associated with a geographic region. As yet another alternative, the current list may be designated based on the presence of trigger items within detection range, each travel list being associated with at least one trigger item.
In one embodiment, a current location is determined. The last known location of each item is stored. For items for which the RFID tag is detected as being within detection range, the current location is set as the last known location of the item. For items for which the RFID tag is not detected as being within detection range, the last known location of the item is indicated.
In accordance with another aspect of the invention, another method is provide for detecting the presence of items labeled with radio frequency identification (RFID) tags. An item is selected from an item list. In response to a query by a user, detection of whether the RFID tag of the item is within detection range is repeatedly attempted. If the RFID tag of the item is within detection range, the user is notified.
Apparatus is also provided for implementing the invention. Instructions for implementing the invention may be stored on a computer-readable medium, the instructions being executable by a processor.
The methods and apparatus of the invention allow a person to rapidly and reliably check that all personal items are with them. By designating lists of important objects which have been labeled with an RFID tag, the invention allows a person to make a simple query of a personal communication device in which the invention is implemented, such as a personal digital assistant or a cellular phone, in order to verify that all personal items on a list are with the person. The inherent communication infrastructure (including support for various RF transmitters, receivers, and modulation codes) and superior user interface of personal communication devices (relative to other portable electronic devices such as watches) may be used to simplify implementation and operation of the invention. The invention allows a user to query for missing items at his or her own convenience which, along with placing the RFID interrogator within the same communication device as the RFID detector, allows the user to query for missing items at any location, even when traveling. In one embodiment, the invention also allows the user to determine where a missing item was last detected.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the invention will become more apparent from the following detailed description of the preferred embodiment(s) with reference to the attached figures, wherein:
FIG. 1 is a block diagram of an item tracking system according to one embodiment of the invention; and
FIG. 2 is a flow chart of a method by which the item tracking system verifies the presence of personal items according to one embodiment of the invention.
It will be noted that in the attached figures, like features bear similar labels.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Referring to FIG. 1 , a block diagram of an item tracking system according to one embodiment of the invention is shown. The item tracking system 8 includes a tracker 10 accessible to a user through a user interface 12 . The tracker 10 is in communication with a Radio Frequency Identification (RFID) detector 13 , which includes an RFID interrogator 14 and an RFID receiver 15 , each of which is in turn in communication with a radio frequency interface 16 . The tracker 10 is also in communication with a memory 18 , which may be any sort of memory accessible by the tracker including RAM stored within the tracker itself or a database within a mobility service provider's core network infrastructure. The tracker is also in communication with a location detector 20 . The item tracking system 8 is preferably located within a personal digital assistant (PDA) or within a cellular phone, although the system may be located within other ubiquitous personal communication devices such as laptop computers. If within a PDA or a cellular phone, then the RF interface may be the normal RF interface of the PDA or the cellular phone, and the user interface is the normal interface of the PDA or cellular phone. Re-use of the RF interface of the personal communication device is particularly advantageous if the personal communication device employs soft radio, since the software control of RF functions through an extremely versatile RF front end allow the invention to be implemented particularly efficiently. If the personal communication device in which the item tracking system 8 is implemented is a wireless communication enabled laptop computer, the RFID detector 13 may be implemented as a USB, PCMIA, or other commonly deployed plug-in module.
The location detector 20 is any device capable of determining the location of the communication device within which the item tracking system 8 is implemented, such as a GPS. Location detectors are becoming more prevalent, and often mandated, in communication devices such as cellular phones, for example for determining the location of a 911 caller. The location detector 20 may be a self-contained sub-component of the portable device, such as a GPS receiver. Alternatively, the location detector 20 may be a sub-element of a location detection system that relies partly on a mobile radio base station infrastructure for location detection through triangulation.
In the preferred embodiment, the tracker 10 is in the form of software within a processor. More generally, instructions for implementing the tracker 10 may be in the form of any combination of software or hardware, including hardware within an integrated circuit. The processor need not be a single device, but rather the instructions could be located in more than one device.
The tracker 10 presents a menu to the user through the user interface. The menu allows the user to manage an item list stored in the memory 18 . The item list contains records, each record corresponding to a personal item. Each record includes an RFID, a name of the personal item, and a location of the personal item. The RFID corresponds to the RFID of an RFID attached to the personal item. The name of the personal item is entered by the user, such as “Wallet” or “Passport”. The menu allows the user to enter the RFID associated with a personal item and the name to be associated with the personal item. The location is entered by the tracker, as described in more detail below. The menu allows the user to enter records for new personal items, to change the names of personal items in the item list, to change the RFID of personal items in the item list, or to delete records from the item list.
The menu also allows users to create one or more travel lists. Each travel list has a name and a list of at least one RFID stored in the item list. For each travel list desired by the user, the user enters a name for the travel list, such as “International travel” and selects one or more RFIDs from the item list. The travel list or lists are stored in the memory 18 . The menu allows users to create new travel lists, to add personal items to existing travel lists by referencing the RFID of the personal item within the item list, to remove personal items from existing travel list, to delete travel lists, and to rename travel lists. The menu also allows the user to designate one of the travel lists as a current list.
The menu also allows users to determine the last known location of personal items in the item list. The location of personal items is stored in the item list as described below with reference to step 40 of FIG. 2 .
To verify the presence of personal items, the user selects the function from the menu displayed on the user interface 12 . Alternatively, an icon may be presented on the display of the device in which the tracker is implemented, which allows the user to verify the presence of personal items with a single touch. As a further alternative, a key or key combination on the device in which the invention is implemented may be tied to the tracker, so that the user can access the presence verification function of the tracker simply by using the existing hardware keys on the device.
Referring to FIG. 2 , a flow chart of a method by which the item tracking system 8 verifies the presence of personal items according to one embodiment of the invention is shown. The method is triggered by the user, as described in the preceding paragraph. At step 30 the tracker accesses the current list, previously designated by the user. If at step 31 the tracker determines that no current list has been designated by the user or that the current list contains no RFIDs, then the user is notified of such at step 32 .
At step 34 the tracker retrieves the next RFID in the current list, which will be the first RFID in the list when the presence verification is started. At step 36 the tracker passes the RFID to the RFID detector 13 . The RFID interrogator 14 within the RFID detector transmits an RF signal through the RF interface 16 in an attempt to prompt RFID tags to transmit their respective RFID. The RFID receiver 15 will detect the presence of the RFID tag if the RFID tag is within range of the RFID receiver, and is unshielded. The preferred detection range of the RFID receiver is 2 meters. If the RFID receiver 15 detects an RFID through the RF interface 16 , the RFID returns a signal to the tracker 10 indicating whether the RFID tag was detected.
If at step 36 the tracker 10 learns that the RFID was not detected, then at step 38 the tracker 10 marks the RFID as missing. The tracker then attempts to identify the next RFID within the current list at step 34 .
If at step 36 the tracker 10 learns that the RFID was detected, then at step 40 the tracker queries the location detector 20 to determine the location of the device in which the invention is implemented. The tracker 10 stores the location in the item list. The tracker then attempts to identify the next RFID within the current list at step 34 .
If the tracker 10 determines at step 34 that there is not a next RFID in the current list, then the tracker 10 has attempted to verify the presence of all personal items within the current list. At step 42 the tracker 10 informs the user through the user interface 12 of the results of the presence verification. The user will either be informed that all personal items within the current list are nearby, or the missing personal items will be identified by the names contained in the item list. At that point, the user may be presented with the option of querying the last known location of the missing personal items.
The invention has been described as monitoring the last known locations of items within the item list. This assumes that the device in which the invention is implemented is equipped with a location detector. While personal communication devices are more frequently being equipped with location detectors, many existing devices have no such location detectors. In an alternative embodiment of the invention, the location detection functions of the invention are either disabled or absent altogether. In such an embodiment, there is no location detector 20 , the records in the item list do not contain location information, and the step 40 of FIG. 2 of determining and storing the location of personal items whose RFID tags are detected is omitted.
The invention has been described as defining travel lists and allowing the user to manually select one of the travel lists as the current list. Alternatively, or additionally, the user may define travel lists with respect to geographic locations. The travel lists are stored in memory associated with geographic parameters, such as bounding latitudes and longitudes, or distance from a geographic point. For example, a first travel list could be associated as within 30 km of a given point, and a second travel list associated as more than 30 km from the given point. When the user queries for the presence of personal items, the tracker 10 retrieves the current location of the personal communication device from the location detector 20 . The tracker consults the travel lists stored in the memory 18 , retrieves the travel list associated with the current location of the personal communication device, and uses that travel list as the current list for determining which personal items are to be scanned for.
As yet another alternative to the user manually selecting one of the travel lists as the current list, each travel list could have an associated trigger personal item or combination of personal items stored in the memory 18 . When the user queries for the presence of personal items, the tracker 10 retrieves the trigger item or items for each travel list and uses the RFID detector 13 to determine which if any of the trigger item or items are within range of the RFID receiver 15 . If a trigger item or combination of items is found to be present, then the tracker 10 uses the associated travel list as the current list for determining which personal items are to be scanned for. If no trigger item or combination of items are found to be present, then the user can be notified of such and prompted to select a current list manually, or the tracker can use a default travel list as the current list.
The invention has been described as performing a single search for at least one personal item stored in a current list. The invention may additionally provide the ability to locate an item through repeated “pinging”. In such an embodiment the user selects a personal item from the item list, effectively creating a current list having only one item. The user selects a locate option, which initiates the item location functionality. In response to the user selection, the tracker determines whether the single item in the current list is within detection range, as described above with respect to step 36 of FIG. 2 . If the item is within detection range, the tracker notifies the user of the item's presence through the user interface. If the item is not within detection range, the tracker may notify the user of the item's absence through the user interface, for example by continuing to display a “Searching . . . ” icon or message. During this process the user would move about with the mobile device in “ping” mode to various locations where the misplaced item might likely be found. The tracker continues to determine whether the item is within detection range until the user enters a halt input, such as by selecting to stop searching from a menu, turning off the electronic device, or selecting a “stop” key.
The item tracking system 8 may be implemented as a tracker 10 within a cellular phone or a PDA, and an RFID detector 13 implemented as a USB or PCMIA plug-in to a laptop computer. The tracker 10 would communicate with the RFID detector 13 via the laptop computer over a simple communication protocol. While not as convenient as implementing the item tracking system 8 on a single electronic device, such an embodiment still provides the advantages of providing a convenient user interface 12 , portability, and the ability of allowing a user to query for the presence of personal items at will rather than passively waiting for a system to alert the user to missing items only when the user passes certain locations equipped with stand-alone RFID interrogators.
The embodiments presented are exemplary only and persons skilled in the art would appreciate that variations to the embodiments described above may be made without departing from the spirit of the invention. Methods that are logically equivalent or similar to the method described above with reference to FIG. 2 may be used to implement the methods of the invention. The scope of the invention is solely defined by the appended claims.
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A system and method are provided for allowing users to verify the presence of personal items. RFID tags are attached to personal items, and the items are entered into a list. The user makes travel lists from the list of items. When traveling, the user queries the system to determine whether all personal items in the travel list are within range of the system. The system checks for the presence of the RFID tags associated with the items in the travel list. If any RFIDs are not present, the user is alerted. Optionally, the system updates the last known location of items whenever checking for the presence of personal items, so that if an item is not found the user can determine where the item was last known to have been.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 11/770,392 filed on Jun. 28, 2007. The entire disclosure of the above application is hereby incorporated herein by reference.
FIELD OF THE INVENTION
The present disclosure relates to a method of operation of a fuel cell system. More particularly, the invention relates to a control of a ventilation system in a rechargeable energy storage system in a vehicle.
BACKGROUND OF THE INVENTION
Various hybrid vehicles have been designed and developed in the automotive industry that operate using fuel cell technology and other rechargeable energy storage and generating systems. In a typical fuel cell vehicle, a fuel cell generates electricity through an electrochemical reaction between hydrogen and oxygen to charge batteries or to provide power for an electric motor. In certain fuel cell vehicles, the vehicle requirements allow a higher power split between a battery system and a fuel cell system. In other words, the fuel cell system is the main energy source having a greater ratio of use than the battery system. The battery system covers peak loads, for example during acceleration, smoothens the fuel cell system load profile to enhance fuel cell system durability, and provides high voltage power in situations where the fuel cell system is not capable of producing power itself such as during startup and shutdown, for example. To support the fuel cell system in these vehicles, the vehicles are equipped with a high power density battery system.
The fuel cell vehicles equipped with the high power density battery system require a ventilation system for the battery system to control a temperature and maintain a performance of the battery cells. Performance of the battery cells is required for full vehicle performance including maximum acceleration and regeneration of kinetic energy during braking. The ventilation system for the battery system is separate from a cooling device controlling a temperature of the fuel cell system, as the temperature set points of the battery system and the fuel cell system are different.
Typically, the ventilation system includes a ventilator fan and a housing, and draws air from the passenger compartment of the vehicle. The air flows through a conduit to the battery system. However, passengers are exposed to noise generated by the ventilator fan and to the air being drawn into the conduit. Moreover, the extraction of air from the passenger compartment by the ventilation system may disrupt circulation of air in the passenger compartment, making it uncomfortable for the passengers in close proximity to the opening. Further, if the mass flow of the air drawn into the ventilation system is greater than the mass flow of the air being emitted by the HVAC system, the air may be drawn back through at least one HVAC system emission outlet into the passenger compartment to equalize the pressure in the passenger compartment, or, if a check valve is installed in the HVAC system emission outlets, the passenger compartment may become under-pressurized creating an uncomfortable environment for the passengers.
U.S. Pat. No. 6,978,855 discloses a cooling system for an electricity storing device in a fuel cell vehicle. The cooling system consists of a plurality of holes formed in the floor of the passenger compartment of the vehicle and a fan. The through holes are provided as inlet ports and outlet ports for a housing of the electricity storing device. The fan is disposed adjacent the inlet ports as a means for discharging air within the housing of the electricity storing device. Air flows into the housing through the inlet ports from the passenger compartment to cool the electricity storing device and is then discharged through the outlet ports into a space under a rear seat in the passenger compartment. Although the outlet ports are disposed at angles to prevent discharged air from directly entering the inlet ports, a temperature of the air drawn into the cooling system is influenced by the discharged air, making the cooling system less efficient. Further, the plurality of holes formed in the floor of the passenger compartment expose the passengers in the passenger compartment to the noise generated by the fan and the air discharged from the housing, thereby decreasing passenger comfort and perceived vehicle quality.
It would be desirable to develop a method for controlling ventilation of a rechargeable energy storage system (RESS) in a fuel cell vehicle, which prevents damage to or a shortened life of the energy storage device, while maximizing durability, efficiency, performance, and passenger comfort.
SUMMARY OF THE INVENTION
In concordance and agreement with the present invention, a method for controlling ventilation of a rechargeable energy storage system (RESS) in a fuel cell vehicle is disclosed, which prevents damage to or a shortened life of the energy storage device, while maximizing durability, efficiency, performance, and passenger comfort.
In one embodiment, the method for controlling the ventilation of a rechargeable energy storage system (RESS) in a vehicle comprises the steps of: providing a ventilation system having an HVAC system in fluid communication with a fluid reserve, and the fluid reserve in fluid communication with the RESS; determining the maximum noise output level of at least one vehicle component; determining the ventilation requirement of the RESS; and controlling the flow rate of a fluid through a fluid transfer device for conveying the fluid from the reserve to the RESS as a function of the maximum noise output level and the ventilation requirement of the RESS.
In another embodiment, the method for controlling the ventilation of a rechargeable energy storage system (RESS) in a vehicle comprises the steps of: providing a ventilation system having an HVAC system in fluid communication with a fluid reserve, and the fluid reserve in fluid communication with the RESS; determining the maximum noise output level of at least one vehicle component; determining the ventilation requirement of the RESS; controlling the flow rate of a fluid through a fluid transfer device for conveying the fluid from the reserve to the RESS as a function of the maximum noise output level and the ventilation requirement of the RESS; and regulating the flow rate of the HVAC system according to the flow rate of the fluid through the fluid transfer device.
In another embodiment, a system for controlling the ventilation of a rechargeable energy storage system (RESS) in a vehicle comprises: a maximum noise output calculating unit in electrical communication with at least one vehicle component; and a fluid transfer device control unit in electrical communication with the maximum noise output calculating unit and the RESS.
DRAWINGS
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of an exemplary embodiment when considered in the light of the accompanying drawings in which:
FIG. 1 is a schematic flow diagram of a ventilation system in a fuel cell vehicle according to an embodiment of the invention;
FIG. 2 is a schematic diagram of a control system for the ventilation system illustrated in FIG. 1 ; and
FIG. 3 is a schematic diagram of a control system for the ventilation system illustrated in FIG. 1 according to another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the present invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. It is understood that materials other than those described can be used without departing from the scope and spirit of the invention. In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, are not necessary or critical.
FIG. 1 illustrates a ventilation system 8 for an energy storage device 40 in a fuel cell vehicle (not shown) according to an embodiment of the invention. The ventilation system 8 includes a heating, ventilation, and air conditioning (HVAC) system 10 which provides a conditioned fluid, a reserve 12 which contains the conditioned fluid, and a rechargeable energy storage system (RESS) 24 which uses the conditioned fluid as a coolant.
The HVAC system 10 includes a fan 16 , an evaporator 18 , and a heater 20 . The fan 16 causes the flow of a desired ratio of ambient fluid and fluid recirculated (not shown) from the reserve 12 through the evaporator 18 . In the embodiment shown, the fluid is air. However, other fluids can be used as desired.
The evaporator 18 cools the fluid traveling though the evaporator 18 in a manner commonly known in the art. The temperature of the fluid is typically lowered from approximately 25 degrees Celsius to 15 degrees Celsius, although it is understood that the temperature can be changed to other values as well.
The fluid may also be heated before exiting the HVAC system 10 . In these situations, a portion of the fluid exiting the evaporator 18 is directed to a heater 20 by a bypass switch 22 . The bypass switch 22 may be a valve or a moveable door, for example. The bypass switch 22 causes a portion of the fluid exiting the evaporator 18 to flow directly to the reserve 12 and the remaining portion of the fluid to flow into the heater 20 . The heater 20 increases the temperature of the fluid traveling through the heater 20 in a manner commonly known in the art. After exiting the heater 20 , the fluid mixes with the fluid flowing directly from the evaporator 18 . If any of the fluid entering the HVAC system 10 passes through the heater 20 , the temperature of the mixed fluid is increased. Typically, the temperature is raised between 15 degrees Celsius and 20 degrees Celsius, although it is understood that the temperature of the mixed fluid can be raised to other temperatures as desired. The conditioned fluid is then exhausted into the reserve 12 .
According to the illustrated embodiment of the invention, the reserve 12 is the passenger compartment of the fuel cell vehicle. The reserve 12 is disposed between the HVAC system 10 and the RESS 24 and is in fluid communication with the HVAC system 10 and a ventilator 14 . The reserve 12 is also in fluid communication with the atmosphere.
The RESS 24 includes the ventilator 14 and a battery system 32 . The ventilator 14 is disposed between the reserve 12 and the battery system 32 . The ventilator 14 includes a hollow housing 34 and a fluid transfer device 36 . The housing 34 is adapted to enclose the fluid transfer device 36 and includes an inlet 30 formed therein in fluid communication with the reserve 12 . Any conventional material can be used to form the housing 34 such as polypropylene, for example. In the embodiment shown, the fluid transfer device 36 is an adjustable speed fan. However, it is understood that the fluid transfer device 36 can be any transfer device known in the art, such as a pump or a turbine, for example. The fluid transfer device 36 causes fluid to flow from the reserve 12 to the RESS 24 .
The battery system 32 includes a housing 38 having a hollow interior and at least one energy storage device 40 . The housing 38 is adapted to contain the energy storage device 40 and includes an outlet 42 formed therein. Any conventional material can be used to form the housing 38 such as polypropylene, for example. In the embodiment shown, the energy storage device 40 is a lithium battery cell. It is understood that the energy storage device 40 can be any energy storage device know in the art such as an accumulator, a super-capacitor or combinations thereof, for example. Typically, the temperature of the fluid entering the battery system 32 is lower than a temperature of the fluid exhausted from the battery system 32 . The temperature of the fluid entering the battery system 32 is typically approximately 20 degrees Celsius. However, the temperature of the fluid can be any temperature, as desired. The battery system 32 is in fluid communication with the ventilator 14 .
In FIG. 2 , a control system 43 for controlling the ventilation of the RESS 24 is shown. The control system 43 includes a maximum noise output calculating unit 44 , a fluid transfer device control unit 46 , and a fluid transfer device restrictor 48 . The noise output calculating unit 44 is in electrical communication with the RESS 24 , a fuel cell system compressor (not shown), a fuel cell vehicle radio (not shown), and the fluid transfer device control unit 46 . The fluid transfer device control unit 46 is in electrical communication with the noise output calculating unit 44 , the RESS 24 , and the fluid transfer device restrictor 48 . The fluid transfer device restrictor 48 is in electrical communication with the fluid transfer device control unit 46 , the HVAC system 10 , and the fluid transfer device 36 .
The noise output calculating unit 44 calculates the maximum noise output level of at least one fuel cell vehicle component or vehicle state. The noise output calculating unit 44 calculates the maximum noise level by looking up and summing values from pre-formulated tables for separate fuel cell vehicle components and vehicle states. In this embodiment, the maximum noise output level is calculated based on the noise output values found in tables 45 a , 45 b , 45 c associated with a RESS power level 50 , a fuel cell system compressor power level 54 , and a radio volume 58 , respectively. The RESS power level 50 is associated with RESS utilization during energy storage regeneration and energy distribution to at least one vehicle system. The compressor power level 54 is associated with the demands of providing oxygen molecules to the fuel cell stack. It is understood that the maximum noise output level may be calculated from pre-formulated tables associated with vehicle components including a radio or from vehicle states, for example an HVAC flow rate, vehicle wheels, ram fluid, or a passenger compartment window position (open/closed), as desired. The maximum noise output level is then used by the fluid transfer device control unit 46 to determine a maximum allowable flow rate of the fluid transfer device 36 .
The fluid transfer device control unit 46 calculates the maximum allowable flow rate based on the ventilation requirement 62 of the battery system 32 , the noise output of the fluid transfer device 36 associated with the ventilation requirement 62 , and the maximum noise output level calculated by the noise output calculating unit 44 . The ventilation requirement 62 is derived from the temperature of the RESS 64 and a desired temperature of the RESS 66 . The maximum allowable flow rate of the fluid transfer device 36 is electronically communicated to the fluid transfer restrictor 48 .
In situations where the flow rate of the fluid transfer device 36 exceeds the HVAC flow rate 72 , the fluid transfer device restrictor 48 limits the flow rate of the fluid transfer device 36 to that of the HVAC flow rate 72 by transmitting a signal 70 corresponding to the HVAC flow rate 72 to the fluid transfer device 36 . The maximum allowable flow rate of the fluid transfer device 36 is found by looking up the corresponding value of the HVAC flow rate 72 in a lookup table 73 . The limitation of the flow rate of the fluid transfer device 36 to that of the HVAC flow rate 72 militates against an under-pressurization of the reserve 12 caused by fluid being drawn from the reserve 12 by the ventilator 14 at a rate greater than the rate of fluid being exhausted into the reserve 12 by the HVAC system 10 .
FIG. 3 depicts a control system 43 ′ for controlling the ventilation of the RESS 24 according to another embodiment of the invention. Reference numerals for similar structure in respect of the discussion of FIG. 2 above are repeated with a prime (′) symbol. The control system includes a maximum noise output calculating unit 44 ′ and a fluid transfer device control unit 46 ′. The noise output calculating unit 44 ′ is in electrical communication with the RESS 24 ′, a fuel cell system compressor (not shown), a fuel cell vehicle radio (not shown), and the fluid transfer device control unit 46 ′. The fluid transfer device control unit 46 ′ is in electrical communication with the RESS 24 ′, the fluid transfer device 36 ′, and the HVAC system 10 ′.
The noise output calculating unit 44 ′ calculates the maximum noise output level of at least one vehicle component or vehicle state. The noise output calculating unit 44 ′ calculates the maximum noise level by looking up and summing values from pre-formulated tables for separate fuel cell vehicle components and vehicle states. In this embodiment, the maximum noise output level is calculated based on the noise output values found in tables 45 a ′, 45 b ′, 45 c ′ associated with a RESS power level 50 ′, a fuel cell system compressor power level 54 ′, and a radio volume 58 ′, respectively. The RESS power level 50 ′ is associated with RESS utilization during energy storage regeneration and energy distribution to at least one vehicle system. The compressor power level 54 ′ is associated with the demands of providing oxygen molecules to the fuel cell stack. It is understood that the maximum noise output level may be calculated from pre-formulated tables associated with vehicle components including a radio or from vehicle states, for example an HVAC flow rate, vehicle wheels, ram fluid, or a passenger compartment window position (open/closed), as desired. The maximum noise output level is then used by the fluid transfer device control unit 46 ′ to determine the maximum allowable flow rate of the fluid transfer device 36 ′.
The fluid transfer device control unit 46 ′ calculates the maximum allowable flow rate based on the ventilation requirement 62 ′ of the battery system 32 ′, the noise output of the fluid transfer device 36 ′ associated with the ventilation requirement 62 ′, and the maximum noise output level calculated by the noise output calculating unit 44 ′. The ventilation requirement 62 ′ is derived from the temperature of the RESS 64 ′ and a desired temperature of the RESS 66 ′. The maximum allowable flow rate of the fluid transfer device 36 ′ is electronically communicated to the fluid transfer device 36 ′ and the HVAC system 10 ′.
Instead of utilizing a fluid transfer device restrictor 48 as shown in FIG. 2 to militate against under-pressurization of the reserve 12 , the control system 43 ′ controls the required HVAC flow rate 78 which meets or exceeds the allowable flow rate of the fluid transfer device 36 ′. The required HVAC flow rate 78 is found from a lookup table 79 based on the allowable flow rate of the fluid transfer device 36 ′. The allowable flow rate of the fluid transfer device 36 ′ is electronically communicated by the fluid transfer device control unit 46 ′ transmitting a first signal 70 ′ to the fluid transfer device 36 ′ and a second signal 76 to the HVAC system 10 ′.
In operation, the system for controlling the ventilation of the RESS 24 can be used to conceal the noise output of the fluid transfer device or to provide acoustic feedback to the passenger that the RESS 24 is storing energy during regeneration mode or delivering energy to a vehicle system. The maximum noise output level is directly proportional to the RESS power level 50 , 50 ′ and at least one vehicle component or vehicle state. Typically, the noise output of the fluid transfer device 36 , is concealed by the noise output of at least one vehicle component or vehicle state. However, during demanding vehicle performance where the RESS 24 utilization and the battery system 32 ventilation requirements are above normal operating levels, the maximum noise output level increases in proportion to the RESS power level 50 , 50 ′. As a result, the noise output of the fluid transfer device 36 may exceed the noise output of the other vehicle components or vehicles states and therefore provide acoustic feedback to the passenger.
From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, make various changes and modifications to the invention to adapt it to various usages and conditions.
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A method of controlling the ventilation system for an energy source in a fuel cell vehicle is disclosed, which includes an HVAC system, a fluid reserve, and a rechargeable energy storage system (RESS), capable of controlling a temperature of the RESS to militate against damage to or a shortened life of the battery, while maximizing vehicle durability, efficiency, performance, and passenger comfort.
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[0001] The present invention relates to configurable fence and gate systems. This application is a continuation-in-part of U.S. application Ser. No. 10/349,643, filed on Jan. 22, 2003, which is incorporated herein by reference.
BACKGROUND
[0002] Man has employed many types of fences having different characteristics to indicate property lines, ensure privacy, segregate activities, and provide barriers for property, people and animals. For example, fences made of stones, bricks, and concrete have long service life, but are difficult to alter after construction. Wood fences have low initial cost, are flexible to alter, but have shorter life when exposed to severe climate or pest infestation. Metal fences having insertable panels are durable, pest resistant and have good service life, but have other problems. For example, the manufacturing tolerances necessary to assemble the metal fences make them vulnerable to vibration and noise generation in wind. One metal fence has lateral stiffeners to hold corrugated sheet metal panels, but the stiffener is a fixed width which limits its application to one width of corrugated sheet metal panel. Another metal fence uses a molded polyvinyl chloride (PVC) interlocking sleeve to hold the fence panels. The interlock sleeve is a fixed width, however, which again restricts flexibility in panels that can be used. In addition, sun exposure degrades the molded PVC interlocking sleeve over time destroying the integrity of the fence.
[0003] Fences also fail to address certain problems. For example property boundaries are often polygons, that is, closed figures made up of line segments. Two adjacent line segments often form a non-perpendicular angle. Thus, fence sections join at non-perpendicular angles yet need freedom to adjust the angle during construction while maintaining connection strength. Separately, gate widths are often oversized to make sure the gate fits, then a lip or shim added to the gate to cover the gap. This lip/shim technique is labor intensive and affects the appearance of the gate. Another problem concerns the attachment of the gate to the fence post. Gates are cantilever structures which stress the gate hinges. The wider or heavier the gate, the more load the hinge must support. The load can fatigue or deform the hinge causing the gate to sag, the hinge hardware to loosen, and even cause damage to the gate frame or gate post. In some cases, if this damages the gate frame or gate post too much, the gate hinges will need to be relocated.
SUMMARY OF THE INVENTION
[0004] The present invention relates to a fence and gate system. In an embodiment, the system includes a pair of fence posts connected by two fence stringers forming a fence framework. The system also includes a pair of L-shaped retainer angles, which are parallel to each other, attached adjacent the fence framework, and define the thickness of the panel to be inserted. The retainer angles are mounted on the surface of the framework either face-to-face or back-to-back forming a slotted frame. At least one fence panel is inserted into the slotted frame. Thus, the invention describes a fence and gate system capable of accommodating a variety of panel styles, materials and thicknesses.
[0005] In other features, the system provides for an insert sandwiched between the panels, an adjustable post angle adapter for joining fence sections, a gate width opening adjuster, and a threaded insert bolt structure that distributes stress in a gate hinge and gate post, but is not strictly limited, to the fence and gate system.
[0006] In various embodiments, the fence and gate system is moderate in cost, easy to install, reconfigure, maintain and repair, and is strong, durable, able to withstand severe climate conditions, pest resistant, and attractive in appearance. In an embodiment, the fence and gate system is made of preformed and pre-coated galvanized steel sheet metal panels, steel structures and extrusions tubing which is readily available, strong, rigid, corrosion resistant, durable, flexible in style, easy to install and reconfigure, and have long service life. In another embodiment, the fence system can support or contain solar panel(s) either for the generation of electrical power or for generating thermal energy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] [0007]FIG. 1 illustrates an embodiment of the fence and gate system.
[0008] [0008]FIG. 2A illustrates an embodiment of the finished fence and gate system.
[0009] [0009]FIG. 2B is an exploded view of fence and gate system shown in FIG. 2A.
[0010] [0010]FIG. 3A is a top view of a fence post shown in FIG. 2A showing face-to-face mounting of a pair of L-shaped side retainer angles to the fence post holding the fence panel.
[0011] [0011]FIG. 3B is a front view of the fence post shown in FIG. 3A.
[0012] [0012]FIG. 3C is an exploded view of the fence post shown in FIG. 3A.
[0013] [0013]FIG. 3D is a top view of the fence post showing back-to-back mounting of a pair of L-shaped side retainer angles to the fence post holding the fence panel.
[0014] [0014]FIG. 3E is an exploded view of the fence post shown in FIG. 3D.
[0015] [0015]FIG. 4A is a top view showing two fence panels sandwiching a panel insert held in place by a pair of L-shaped side retainer angles.
[0016] [0016]FIG. 4B is a front view of one fence panel shown in FIG. 4A.
[0017] [0017]FIG. 4C is an enlarged top view of the fence panels held in place by a pair of L-shaped side retainer angles partially shown in FIG. 4B.
[0018] [0018]FIG. 5A illustrates a fence and gate system configured to use fence boards.
[0019] [0019]FIG. 5B is a top view of the fence and gate system shown in FIG. 5A.
[0020] [0020]FIG. 5C is a sectional side view of the fence and gate system shown in FIG. 5A.
[0021] [0021]FIG. 6A illustrates the frame of the fence and gate system shown in FIG. 5A.
[0022] [0022]FIG. 6B shows the top view of the frame shown in FIG. 6A.
[0023] [0023]FIG. 7A is an enlarged view of the fence post with stringers shown in FIG. 6A.
[0024] [0024]FIG. 7B is a top view of the fence post with stringers shown in FIG. 7A.
[0025] [0025]FIG. 8A illustrates post angle adapters as used in the fence and gate system.
[0026] [0026]FIG. 8B shows the top view of post angle adapters shown in FIG. 8A.
[0027] [0027]FIG. 9A is an enlarged front view of the post angle adapter to connect a gate frame to a section of the fence frame also shown in FIG. 8A.
[0028] [0028]FIG. 9B is an exploded top view of the post angle adapter shown in FIG. 9A.
[0029] [0029]FIG. 10A is a detailed front view showing another post angle adapter for connecting fence sections also shown in FIG. 8A.
[0030] [0030]FIG. 10B is a detailed exploded assembly top view of FIG. 10A.
[0031] [0031]FIG. 11A is a detailed front view showing part of the gate frame attached to the fence post through a gate hinge also shown in FIG. 8A.
[0032] [0032]FIG. 11B is a top section view of FIG. 11A showing the use of gate post threaded insert assemblies holding the gate hinge in place.
[0033] [0033]FIG. 11C is a detailed view of FIG. 11B showing the design of the gate post threaded insert.
[0034] [0034]FIG. 12A is a front view of a gate frame and a gate width opening adjuster assembly in another embodiment, wherein the gate hinges are on the left side.
[0035] [0035]FIG. 12B is a section view of one end of a gate frame in FIG. 12A showing a welded on surround metal back flange.
[0036] [0036]FIG. 12C is a full section view of FIG. 12A.
[0037] [0037]FIG. 12D is an exploded assembly view of FIG. 12C showing the gate hinge and the attachment of the gate width opening adjuster to the opposite end.
[0038] [0038]FIG. 13 is a perspective view of a section of the configurable fence system with solar panels and support structure added onto the fence.
[0039] [0039]FIG. 14 is a front view of a section of the configurable fence system with solar panels and the support structure.
[0040] [0040]FIG. 15A is a top view of the solar panels and the support structure with one panel removed to show an underlying electrical wiring box.
[0041] [0041]FIG. 15B is a front view of the support structure without any solar panels.
[0042] [0042]FIG. 16A is an end view of the support structure and the solar panels.
[0043] [0043]FIG. 16B is a sectional view showing the details of the support structure.
[0044] [0044]FIG. 17 is an exploded end view of the support structure.
[0045] [0045]FIG. 18 is an enlarged detailed view showing the angle adjusting arms.
[0046] [0046]FIG. 19 is a perspective view of another embodiment of the configurable fence system showing two solar panels installed over the existing vertical panel surface area of the fence section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] The following description includes the best mode of carrying out the invention. The detailed description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the claims. Each part, even if structurally identical to other parts, is assigned its own part number to help distinguish where the part appears in the drawings.
[0048] [0048]FIG. 1 illustrates the fence and gate system. As shown in FIG. 1, the fence and gate system includes at least one fence section 17 connected to at least one gate assembly 12 . The embodiment can be configured to different fence framework styles as well as gate styles to fulfill the requirements and needs according to the user's imagination. This flexibility in configuration will be illustrated with examples as other embodiments of the present invention later.
[0049] [0049]FIG. 2A shows the finished fence and gate system in an embodiment including the parts that comprises it. FIG. 2B is an exploded view of the assembled fence and gate system shown in FIG. 2A. FIGS. 2 A- 2 B shows the parts of the fence and gate system. Each fence section 17 includes two fence posts 26 , 27 , which in one embodiment are constructed of industry standard thickness precoated galvanized steel tubing of predetermined length. Each end of the fence section 17 is anchored to the foundation or soil 34 by fence posts 26 , 27 . Placed on top of each fence posts 26 , 27 is a post cap, such as post cap 24 on fence post 26 . It can be a variety of styles such as an ornamental post cap to keep out rain or ornamental lamp (not shown). A fence stringer 22 , which in one embodiment is constructed of industry standard thickness galvanized steel tubing of predetermined length, is placed at the bottom with specified clearance from the soil, and connects the two fence posts 26 , 27 . Each end of the fence stringer 22 is firmly attached to the fence posts 26 , 27 using a pair of stringer hangers 13 , 19 and a plurality of self drilling and self tapping screws identical to the screw 42 shown in FIG. 3A.
[0050] A pair of cross section L-shaped retainer angles, the front L-shaped retainer angle 20 being shown, which in one embodiment are constructed of industry standard thickness precoated galvanized steel sheet metal extrusion of predetermined length, are fastened parallel and face-to-face to the fence stringer 22 using a plurality of self drilling and self tapping screws such as the screw 42 forming a cross section U-shaped slot along the length of the fence stringer 22 .
[0051] A pair of cross section L-shaped side retainer angles 30 , 31 , which in one embodiment are constructed of industry standard thickness precoated galvanized steel sheet metal extrusion of predetermined length, are fastened parallel and face-to-face to the interior side of each fence post 26 , 27 using a plurality of self drilling and self tapping screws identical to the screw 42 forming a cross section U-shaped slot along the length of the interior side of the fence posts 26 , 27 .
[0052] A cross section U-shaped three-sided slotted fence framework is thus formed to insert and to hold the fence panels 28 , 33 and the lattice fence panel 18 in place. The fence panels 28 , 33 are constructed of but not limited to corrugated precoated galvanized steel sheet metal of predetermined length, wood, plastic, fiber glass or composite material, and the lattice fence panel 18 is constructed of but not limited to wood, steel sheet metal or other materials, are inserted into the slotted structure sequentially. The design of the individual panels such lattice or corrugated etc. is not considered to be essential to the present invention and is simply a matter of preference.
[0053] A pair of cross section L-shaped retainer angles, the front L-shaped retainer angle 21 being shown, is fastened parallel and face-to-face to a fence stringer 23 using a plurality of self drilling and self tapping screws identical to the screw 42 forming a cross section U-shaped slot along the full length of the fence stringer 23 . The lattice fence panel 18 is capped under compression by the slotted top fence stringer assembly. The fence stringer 23 is firmly attached on both ends to the fence posts 26 , 27 using a pair of stringer hangers 15 , 16 on each side, and a plurality of self drilling and self tapping screws identical to the screw 42 . If necessary, additional self drilling and self tapping screws can be used to hold the panels in place.
[0054] In another embodiment, the L-shaped retainer angles 20 , 21 and the L-shaped side retainer angles 30 , 31 can be fastened parallel and back-to-back on the fence stringers 22 , 23 and fence posts 26 , 27 to form a cross section U-shaped three-sided slotted fence framework in similar manner to that shown in FIGS. 3D and 3E.
[0055] The gate assembly 12 is in one embodiment constructed of Industry standard thickness galvanized steel tubing and sheet metal strips of predetermined length.
[0056] The rectangular structure is welded together with a surround back metal flange 82 (FIG. 11B) to form a gate frame 38 with resemblance to a picture frame. A plurality of gate hinges such as gate hinge 14 is welded onto the gate frame 38 . The gate panel 40 constructed of material not limiting to corrugated precoated steel sheet metal or wood and the lattice gate panel 36 constructed of not limiting to wood, steel sheet metal or other material, are fastened onto the gate frame 38 using a plurality of self drilling and self tapping screws identical to screw 42 to form the gate assembly 12 . The gate assembly 12 is firmly attached to the fence post 27 through a plurality of gate hinges identical to gate hinge 14 , using a combination of a plurality of hardware to be described in detail in FIGS. 11A, 11B and 11 C. A gate width opening adjuster 10 is attached to the gate frame 38 using a plurality of self drilling and self tapping screws identical to screw 42 . Those who are skilled in arts will realize that the panel and lattice material used in the preferred embodiment is not limited to precoated sheet metal, wood, plastic, composite material, fiber glass and therefore is not restrictive in interpretation.
[0057] [0057]FIG. 3A is a detailed top section view of the fence post in an embodiment. A pair of cross section L-shaped side retainer angles 25 , 30 , which in one embodiment are constructed of industry standard thickness precoated galvanized steel sheet metal extrusion of predetermined length, are fastened parallel and face-to-face to the interior vertical side of each fence post using a plurality of self drilling and self tapping screws identical to the screw 42 forming a cross section U-shaped slot along the interior side of the fence posts 26 . A fence panel 28 of certain thickness that determines the spacing of the cross section L-shaped side retainer angles 25 , 30 is held tightly in the cross section U-shaped slot formed.
[0058] [0058]FIG. 3B is a front view of FIG. 3A showing the fence panel 28 being held in place by a pair of cross section L-shaped side retainer angles, the front angle 30 being shown. FIG. 3C is an exploded assembly view of the fence post shown in FIG. 3A. FIG. 3D is a detailed top section view of the fence post in another embodiment. A pair of cross section L-shaped side retainer angles 25 , 30 , which in one embodiment are constructed of industry standard thickness precoated galvanized steel sheet metal extrusion of predetermined length, are fastened parallel and back-to-back to the interior vertical side of the fence post 26 using a plurality of self drilling and self tapping screws identical to screw 42 forming a cross section U-shaped slot along the interior side of the fence post 26 . A fence panel 29 has a certain thickness that determines the spacing between the cross section L-shaped side retainer angles 25 , 30 is held tightly in the cross section U-shaped slot formed. FIG. 3E is an exploded assembly view FIG. 3D showing the parts that comprise the structure.
[0059] The U-shaped slot formed in the embodiments shown in FIGS. 3A and 3D has the flexibility to accept fence panels 28 , 29 of different thicknesses by adjusting slot width or mounting orientations without the need to change the types of fence parts.
[0060] [0060]FIG. 4A shows the top view of panel in another embodiment with a panel sandwiching configuration. FIG. 4B is a front view of FIG. 4A with sandwiching panel configuration held in place by a pair of retainer angles 20 , 47 (FIG. 4C) on each side. FIG. 4C is a detailed view of FIG. 4A. The panels 43 , 45 are held tightly in place by a pair of retainer angles 20 , 47 . The fence panels 43 , 45 are constructed of a wide range of material and are not limited to such as precoated corrugated sheet metal, wood, plastic, fiber glass or any composite material. The panel insert 44 is constructed of a wide range of material and not limited to such as fiber board, plastic, composite or foam. The panel insert 44 functions as spacer to fill slack under compression from the retainer angles 20 , 47 on each side. If the panel insert 44 material has acoustic property, it also functions as a noise suppression layer to dampen panel resonance, vibration or echoes under wind load and traffic noise. The extent of sandwiched area may vary from a full fence width to a portion of the fence width.
[0061] [0061]FIG. 5A illustrates an embodiment using substantially identical parts that can be configured to accept traditional fence boards 48 and gate boards 46 . In various embodiments, the parts could be made of wood, metal, or a combination thereof. The parts will be now described as primarily of wood. FIG. 5B shows the top view of the fence and gate shown in FIG. 5A. A plurality of stringer angle hanger identical to the angle hangar 51 and a wood horizontal gate stringer 50 are used in this configuration. FIG. 5C shows the sectional side view of FIG. 5A. The fence stringers 22 , 23 are rotated 90 degree from what was described in the earlier embodiment, and mounted on the top and the bottom across the fence posts 26 , 27 with a plurality of stringer angle hangers identical to the stringer angle hangar 51 . Wood horizontal fence stringers 54 , 55 are attached to the fence stringers 22 , 23 through a plurality of stringer angle hangers 52 , 53 and wood screws. Wood fence boards 48 are attached onto the horizontal fence stringers 54 , 55 by a plurality of wood screws.
[0062] [0062]FIG. 6A illustrates the frame of fence and gate system shown in FIG. 5A. It can be made of wood, metal or a combination thereof. Thus, wood horizontal fence stringers 54 , 55 are attached to the fence stringers 22 , 23 through a plurality of stringer angle hangers including the stringer hangers 52 , 53 and wood screws forming a hybrid metal and wood member framework across the full fence width on the top and the bottom. Wood fence boards 48 are to be attached to the hybrid framework by a plurality of wood screws forming a traditional wood fence. A wood horizontal gate stringer 50 is attached to the top of the gate frame 66 by a plurality of machine screw/bolts 58 , flat washers 64 , nut and flat washer assemblies 62 . The wood horizontal gate stringer 50 length can be sized accordingly to provide a good fit to the gate width opening functioning and a gate width opening adjuster. The style of the gate frame 66 is not limiting to this embodiment that has a cross brace welded diagonally to increase support of the wood gate boards 46 .
[0063] [0063]FIG. 6B is the top view of the system shown in FIG. 6A showing the hybrid metal wood framework in this embodiment. The gate frame 66 is attached to the fence post by a gate hinge 14 and a combination of gate post threaded inserts 32 and bolt and flat washer assembly 72 .
[0064] [0064]FIG. 7A is a detailed view 60 of the fence post 26 shown in FIG. 6A, which is connected differently to the stringers 23 , 69 . In this embodiment, the fence stringer 23 is rotated 90 degrees. The two stringer angle hangers 51 , 56 , one on the top end and the other in the bottom end of the fence stringer 23 are mounted to the fence post 26 using a plurality of self drilling and self tapping including the screws 67 , 49 .
[0065] [0065]FIG. 7B is a top view of FIG. 7A showing the configurations of fence stringers 23 , 69 mounted to the fence post 26 . The fence stringer 69 is mounted without rotation to the fence post 26 using a pair of stringer hangers 16 , 59 one on each side and a plurality of self drilling and self tapping screws identical to the numbered screws 57 , 73 .
[0066] [0066]FIG. 8A illustrates the use of post angle adapters 70 , 76 of the fence and gate system. The gate is connected to another section of the fence using a post angle adapter 70 that has an acute angle of about 20 degrees. The fence is connected to another section of the fence through another post angle adapter 76 that has an acute angle of about 45 degrees. One of ordinary skill would understand that these illustrated angles are not essential to the invention. The details of gate hinge 74 will be discussed later.
[0067] [0067]FIG. 8B shows the top view of FIG. 8A showing the post angle adapters 70 , 76 .
[0068] Both the post angle adapters 70 and 76 , which in one embodiment are constructed of standard industry thickness preformed and precoated steel sheet metal parts, can be formed in a range of angle increments to connect adjacent sections of the fence structure.
[0069] [0069]FIG. 9A is a detail front view of FIG. 8A showing a gate frame 66 connected to another section of the fence on a fence post 27 using a post angle adapter 70 . The post angle adapter 70 is attached firmly to the gate post 27 on both sides using a plurality of self drilling and self tapping screws identical to the numbered screw 65 .
[0070] [0070]FIG. 9B is a detail top view of portion 80 shown in FIGS. 8B and 9A. In this illustration, a gate frame 66 is connected to another section of the fence on a fence post 27 using a post angle adapter 70 and a plurality of self drilling and self tapping screws identical to screw 63 . The fence stringers 71 , 75 are connected to the post angle adapters 70 with a pair of stringer hanger 61 , 73 on each side and a plurality of self drilling and self tapping screws identical to screws 63 , 89 . In this illustration, an angle of 20+/−10 degree can be achieved by flexing the post angle adapter 70 from its mounted position on the fence post 27 . It is also shown that the stringer hanger 61 on one side of the fence stringer 71 is being flexed slightly. This minor flexing is tolerated by the steel sheet metal material construction.
[0071] [0071]FIG. 10A is a detailed front view showing using another post angle adapter 76 to connect two fence sections together in FIG. 8A. The post angle adapter 76 is attached firmly to the gate post 26 on both sides using a plurality of self drilling and self tapping screws 81 , 83 . FIG. 10B is a detailed top view of portion 78 shown in FIGS. 8B and 10A. In this illustration, two fence sections are connected on a fence post 26 using a 45+/−10 degree post angle adapter 76 and a plurality of self drilling and self tapping identical to the screws 81 , 91 . It is also shown that there is no flexing on the stringer hanger 90 , 92 on either side of the fence stringer 77 using this post angle adapter 76 .
[0072] [0072]FIG. 11A is a detailed front view of portion 74 shown in FIG. 8B. This shows the portion of the gate frame 66 attached to the fence post 27 through a gate hinge 14 in FIG. 8A.
[0073] [0073]FIG. 11B is a section view of FIG. 11A showing the use of a gate post threaded insert 32 with a gasket 82 swaged tightly with the matching bolt and flat washer assemblies 72 across both sides of the fence post 27 holding the gate hinge 14 in place. Also shown is gate frame 66 connected to the gate hinge 14 .
[0074] [0074]FIG. 11C is a detail view of FIG. 11B showing the design of the gate post threaded insert 32 . The gate post threaded insert 32 in an embodiment is machined from a solid hard metal or alloy such as steel. One end forms the head with a pattern that can be held in place or driven with a tool. The head pattern is not limiting in its current hexagonal design. A nut driver or other tools can be fitted over the head to hold the gate post threaded insert 32 in position or to rotate for tightening. The body of the gate post threaded insert 32 is smooth. The tail end is blind drilled and tapped to a specified depth. The thread size of the gate post threaded insert 32 will be industry standard. It is threaded to mate with common and available bolt hardware. It should be pointed out that the outer body of this preferred embodiment structure can be machined to a lower diameter forming a minor diameter at the tail end for hole clearance to the steel fence post 27 when under tight compression.
[0075] In the preferred embodiment, the gate post threaded insert 32 is used together with a combination of the gasket 82 for a moisture seal and a bolt and flat washer assembly 72 to achieve tight compression on both surfaces of a hollow steel fence post 27 . Along with the benefits of other anticipated applications, one of the purposes of this gate post threaded insert 32 is to distribute suspended load stress across the entire hardware assembly. This improves the strength of the hardware holding the gate hinge 14 . It is understood that the post threaded insert 32 is suitable for a variety of application beside its illustrated use in the fence and gate systems.
[0076] [0076]FIG. 12A is a front view of a gate frame 39 and a gate width opening adjuster 10 in another embodiment, wherein the gate hinges, e.g., gate hinge 14 are on the left side. FIG. 12B is a section of one end of the gate frame shown in FIG. 12A showing a weld 84 between the gate frame 39 to the surround metal back flange 86 .
[0077] [0077]FIG. 12C is a full section view of FIG. 12A. The gate width opening adjuster 10 in one embodiment is constructed of Industry standard thickness galvanized steel metal extrusion or formed from sheet metal. The top end of the gate width opening adjuster 10 is welded close to keep rain out while the other end is open for venting. The gate hinge 14 is welded to the gate frame 39 .
[0078] [0078]FIG. 12D is a detailed exploded assembly view of FIG. 12C showing the gate hinge plate 14 welded to the gate frame 39 to one end and the attachment of the gate width opening adjuster 10 to the opposite end. The width adjustment is achieved by attaching the gate width opening adjuster 10 at the opposite end of the gate frame 39 by sliding back and forth to determine the position using a plurality of self drilling and self tapping screws identical to screw 87 . The gate panel 88 is screwed down to the surround metal back flange 86 using a plurality of self drilling and self tapping screws identical to screw 93 . This gate width opening adjustment method eliminates the use of a gate shim or lip.
[0079] [0079]FIG. 13 is a perspective view of an embodiment of the configurable fence system 100 showing solar panels 102 , 103 installed over the support structure 110 that is mounted on top of a fence section 104 . The support structure 110 spans the length of the fence section 104 to support the solar panels 102 , 103 , where the solar panels 102 , 103 convert solar energy into either electrical power or thermal energy for a variety of applications. This has several advantages since solar power generation research has become a mature technology with much improved power conversion efficiency. With sufficient solar panels it is possible to supply much if not all the power requirements to the household and even with spare power to sell back to the power grid during certain hours of the day. With solar power installation rebate incentives from the power company along with tax credit from some state and the federal government, the rate of return on the total energy cost savings after rebates and tax credit is attractive. The fence system, solar panels, and installation cost may be recaptured within several years.
[0080] [0080]FIG. 14 shows the front view of a section of the configurable fence system 100 with a solar panel 102 installed on the mounting surface 117 of the support structure 110 that is mounted on top of the fence posts 106 , 107 of a fence section 104 through the post extensions 112 , 111 .
[0081] [0081]FIG. 15A is a top view of the support structure 110 with one solar panel 102 removed to expose the mounting surface 117 . The mounting surface 117 shows an opening to an electrical wiring box 134 where electrical wiring from solar panel 102 passes through. The solar panels 102 , 103 in this embodiment are known as solar panels or mats such as a Uni-Solar™ photovoltaic laminate of standard length with adhesive backing that adheres to the mounting surfaces 116 , 117 . A suitable material for the mounting surfaces 117 , 116 is an electro-galvanized sheet metal that can be obtained from Galvalune™.
[0082] [0082]FIG. 15B is a front view of the support structure 110 with solar panel 102 removed.
[0083] The entire support structure 110 slides over the fence posts 106 , 107 , on each side of stringer 23 , through the post extensions 112 , 111 on both ends. FIG. 17 will describe additional details of the electrical wiring box 134 , angle adjusting arm 113 , center support and wiring tray 118 and the wire raceway cover 120 .
[0084] [0084]FIG. 16A is an end view of the support structure and solar panels. In an embodiment, the support structure 110 is preferably made of powder coated galvanized sheet metal steel mounted on top of a fence section 104 (FIG. 14). To install the support structure 110 on the fence section 104 , the post cap on the fence is removed and the post extension 112 is inserted into the fence post 106 . Likewise, the post extension 111 (FIG. 14) is inserted into the fence post 107 (FIG. 14) In an alternative embodiment, the fence posts 106 , 107 can extend vertically upward to serve as post extensions 112 , 111 so that the support structure 110 is an integral extension of the fence section 104 . The fewer parts in this embodiment permit faster assembly when the owner knows solar panels 102 , 103 will be used with the fence.
[0085] [0085]FIG. 16B is a sectional view of the support structure 110 taken on line A-A of FIG. 15B. In this embodiment, the support structure 110 includes arm 114 , 113 to independently tilted mounting surfaces 116 , 117 whose tilt angle can be adjusted manually or by a conventional closed loop control system using solar detection by providing a motor (not shown) to actuate the arms 113 , 114 so electric power generation is maximized.
[0086] [0086]FIG. 17 is an exploded end view of the support structure 110 . In this embodiment, the solar panel 103 rests over the mounting surface 116 with an opening where an electrical wiring box 134 with wiring conduit 136 assembly beneath the mounting surface 116 brings the insulated electrical wiring from the solar panel 103 to the center support and wiring tray 118 . The rectangular mounting panels 116 , 117 with electrical wiring boxes 134 , 133 underneath are connected to the center support and wiring tray 118 that can be made from a single piece gutter like corrugated steel structure through a pair of support hinges 122 , 123 to allow certain degree of angular movement. The center support and wiring tray 118 is a conduit for the insulated wire conducting the electrical current to the adjacent fence sections or to the power grid.
[0087] A wire raceway cover 120 can be also made of a single piece of sheet metal which is secured as a cover with driller screws 147 , 149 to the center support and wiring tray 118 to protect the insulated electrical wiring from rain and sunlight weathering. An arm support plate 126 is welded beneath the center support and wiring tray 118 to function as a pivot point to provide angular adjustment by allowing the angle adjusting arms 113 , 114 to slide along the slots 150 , 152 . The opposite ends of the angle adjusting arms 113 , 114 are connected to the angle brackets 124 , 125 that are welded onto the mounting surfaces 116 , 117 . The bolt and nut assemblies 144 , 145 , 146 are to hold the angle adjusting arms 113 , 114 in place. The entire support structure 110 is secured in place at both ends to the post extension 112 and post extension 111 (FIG. 14) with a plurality of driller screws 148 , 300 , and inserted over the fence post 106 and fence post 107 (FIG. 14).
[0088] [0088]FIG. 18 is an enlarged detailed view showing the angle adjusting arms 113 , 114 where angular adjustment is made by sliding the arm along the slots 150 , 152 then locking the position in place by tightening the bolt and nut assembly 146 . The entire supporting structure 110 may be constructed with any high strength material with acceptable life expectancy.
[0089] [0089]FIG. 19 is a perspective of an embodiment of configurable fence system 130 where one or more solar panels 302 , 304 can be installed in place as described above or laminated over the existing vertical fence panels of the fence section 104 .
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The present invention relates to flexible fence and gate systems, which are flexible to alterations, have common parts, are easy to assembly, durable, and have long service life. The frame can be made of pre-coated galvanized steel parts. The panel is held in a U-shaped slotted rectangular fence frame formed by a parallel pair of L-shaped retainer angles mounted back-to-back or face-to-face on the stringers to accommodate a wide choice of panel styles, materials and thicknesses without adding any new components. Another feature provides a panel insert which can be sandwiched between two panels to further suppress noise. Another feature relates to adjustable post angle adapters. Another feature relates to a gate width opening adjustment member using a sliding rail at the far end. A bolt threaded insert structure can be used at the gate hinges to distribute the load of the gate across the gate hinge hardware.
The configurable fencing system can be configured to allow add on structures for solar panels mounting to generate substantial electrical power. In an embodiment, the add on structure is a framework that holds a large mounting surface area for the solar panels and is capable of adjusting the angle to optimal incident sunlight, with means to relay the generated electrical current to the adjacent fence sections or to the power grid. In another embodiment, without any add on structure or framework, one or both sides of the vertical fence panels can be used as mounting surface for the solar panels as well.
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TECHNICAL FIELD
The present invention relates to computer managed communication networks of interactive display stations, such as the World Wide Web (Web) or like private networks, and particularly to applications of such networks for user interactive monitoring of telephone conferencing.
BACKGROUND OF RELATED ART
The past decade has been marked by a technological revolution driven by the convergence of the data processing industry with the consumer electronics industry. The effect has, in turn, driven technologies that have been known and available but relatively quiescent over the years. A major one of these technologies is the Internet or Web related distribution of documents. The Web or Internet, which had quietly existed for over a generation as a loose academic and government data distribution facility, reached “critical mass” and commenced a period of phenomenal expansion. With this expansion, businesses and consumers have direct access to all matter of documents and media through the Web.
Also, because of this extensive access of businesses and consumers to the Internet or Web (used interchangeably herein), it is highly likely that anyone who might be asked to participate in a telephone conference would also have access to the Web. Such demographics has led the industry to seek applications in which the Web could be used in telephone conferencing. The present invention considers one such potential application.
The use of telephone conferencing in commerce and industry has undergone some changes that were not anticipated a decade ago. At that time, the trend appeared to be toward teleconferencing between sets of high technology studios each with groups of people and closed circuit television therebetween. While some of these set ups are still quite active, the business world appears to have moved back to a more basic and less expensive telephone conferencing in which individuals and remote telephone stations, each with either single attendees or conferees or groups of people over speaker phones participate in the telephone conference. This rather basic telephone conferencing has been proliferating world-wide driven by the economic and terrorist fear curtailment of travel.
While this form of telephone conferencing has been used quite effectively to save time and money, participants, i.e. conference attendees, have encountered some problems. First, during the initiation of the telephone conference, time is wasted as the participants connect on one by one until the quorum of requisite attendees is connected. Then, when several people are talking over the lines during the same time period, it is hard for each attendee to know who is who. Likewise, it is hard for the conference host or any other interested party to know when a required attendee has disconnected.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a system for monitoring such teleconferencing that reduces the above-mentioned problems. The invention is directed to the monitoring of any conventional telephone conference in which a requisite set of conference attendees respectively at a corresponding set of telephone stations are connected into a telephone conference. The invention provides in association with the telephone conference, a communication network with user access via a plurality of data processor controlled interactive display stations for displaying received network documents available from sources on the network in which there is an interactive display station associated with each of said set of telephone stations with a displayed document including an indicator representing each attendee having means for indicating whether the attendee's telephone station is connected into the conference, and means for indicating whether the attendee is speaking.
The present invention also provides some valuable expedients for initiating such telephone conferences involving the combination of means (during the initiation period) for placing on-call each telephone station initially connecting into the conference, and means for calling these on-call telephone stations into the conference when a quorum of said requisite attendees has connected into the conference. This initiation process may be automated through means for determining when the quorum of required attendees has connected into the conference, and rendering the means for calling the on-call telephone stations automatically responsive to the means for determining when said quorum has connected.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood and its numerous objects and advantages will become more apparent to those skilled in the art by reference to the following drawings, in conjunction with the accompanying specification, in which:
FIG. 1 is a block diagram of a data processing system including a central processing unit and network connections via a communications adapter that is capable of implementing the interactive display terminals, as well as servers in the network, e.g. Web distribution of the display panels supporting the telephone stations in the conferences;
FIG. 2 is a generalized view of an illustrative system in which a Web network display panel distribution may be used in the support of a telephone conference according to the practice of the present invention;
FIG. 3 is a diagrammatic illustration of an interactive display interface panel used by the conference host in the setting up of the ancillary Web station display panels supporting the telephone conference at the display station of each attendee;
FIG. 4 is an illustrative example of an interactive display panel distributed to each teleconference at the initial stage when the conference is still idle;
FIG. 5 is a display interface panel like that of FIG. 4 but after the teleconference has been commenced (initiation stage), and attendees are being connected and placed on call;
FIG. 6 is a display interface panel like that of FIG. 5 but after the active teleconference has been commenced, and the attendees are speaking to each other;
FIG. 7 is an illustrative flowchart describing the setting up of the functions to monitor telephone conferences on supporting network display panels according to the present invention; and
FIG. 8 is a flowchart of an illustrative run of the program set up according to FIG. 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , a typical data processing system is shown that may function as the computer controlled network terminals or Web stations used for the display of the screen pages or panels supporting the telephone conference. The system shown is also illustrative of any of the server computers used for the Web page or panel distribution to be described in greater detail with respect to FIG. 2 .
A central processing unit (CPU) 10, may be one of the commercial microprocessors in personal computers available from International Business Machines Corporation (IBM) or Dell Corporation; when the system shown is used as a server computer at the Web distribution site to be subsequently described, then a workstation is preferably used, e.g. RISC System/6000™ (RS/6000) series available from IBM. The CPU is interconnected to various other components by system bus 12 . An operating system 41 runs on CPU 10 , provides control and is used to coordinate the function of the various components of FIG. 1 . Operating system 41 may be one of the commercially available operating systems such as the AIX 6000™ operating system available from IBM; Microsoft's Windows XP™ or Windows2000™, as well as UNIX and AIX operating systems. Application programs 40 , controlled by the system, are moved into and out of the main memory Random Access Memory (RAM) 14 . These programs include the programs of the present invention for the monitoring of telephone conferences on display station screen panels ancillary to and supportive of associated telephone stations connected in the telephone conference.
In the examples to be described, we will use the Web for the distribution of the monitoring display panels at the Web stations. Any conventional Web browser application program, such as Microsoft's Internet Explorer™, or Lotus Notes™ Personal Web Navigator or Server Web Navigator will be available for distributing the monitoring Web pages or panels to the network stations associated with the telephone conference stations. A Read Only Memory (ROM) 16 is connected to CPU 10 via bus 12 and includes the Basic Input/Output System (BIOS) that controls the basic computer functions. RAM 14 , I/O adapter 18 and communications adapter 34 are also interconnected to system bus 12 . I/O adapter 18 communicates with the disk storage device 20 . Communications adapter 34 interconnects bus 12 with the outside network enabling the computer system to communicate with other such computers over the Web or Internet. The latter two terms are meant to be generally interchangeable and are so used in the present description of the distribution network. I/O devices are also connected to system bus 12 via user interface adapter 22 and display adapter 36 . Keyboard 24 and mouse 26 are all interconnected to bus 12 through user interface adapter 22 . It is through such input devices that the user at a receiving station may interactively relate to the Web in order to access Web documents. Display adapter 36 includes a frame buffer 39 that is a storage device that holds a representation of each pixel on the display screen 38 . Images may be stored in frame buffer 39 for display on monitor 38 through various components, such as a digital to analog converter (not shown) and the like. By using the aforementioned I/O devices, a user is capable of inputting information to the system through the keyboard 24 or mouse 26 and receiving output information from the system via display 38 .
Before going further into the details of specific embodiments, it will be helpful to understand from a more general perspective the various elements and methods that may be related to the present invention. Since an aspect of the present invention is directed to documents such as screen panels transmitted over networks, an understanding of networks and their operating principles would be helpful. We will not go into great detail in describing the networks to which the present invention is applicable. Reference has also been made to the applicability of the present invention to a global network, such as the Internet or Web. For details on Internet nodes, objects and links, reference is made to the text, Mastering the Internet, G. H. Cady et al., published by Sybex Inc., Alameda, Calif., 1996. The Internet or Web is a global network of a heterogeneous mix of computer technologies and operating systems. Higher level objects are linked to the lower level objects in the hierarchy through a variety of network server computers. E-mail is distributed through such a network.
A generalized diagram of a portion of the Web for illustration of the telephone conferencing and monitoring system of the present invention is shown in FIG. 2 . The telephone conference may be a conventional teleconference set up with a plurality of remote telephone stations 25 , 26 , 27 and 28 through which the invited conference attendees call-in or are called-in and are interconnected through standard Public Switched Telephone Networks (PSTNs) 23 in a standard manner. The telephone stations may be conventionally wired into the conference through the PSTNs or the stations may be wireless cellular telephone stations connected into the PSTN through conventional wireless cellular networks. Each telephone station 25 – 28 has an associated Web network terminal 11 , 13 , 15 and 17 with displays 57 upon which the screen panels 56 may be displayed. Terminals 11 , 13 , 15 and 17 may be implemented by the computer system setup in FIG. 1 , and connection 58 ( FIG. 2 ) is the network connection shown in FIG. 1 . For purposes of the present embodiment, terminals 11 , 13 , 15 and 17 are representative of the Web display stations for respectively supporting and monitoring telephone stations 25 – 28 to be described with respect to FIGS. 3 through 6 . Reference may be made to the above-mentioned, Mastering the Internet, pp. 136–147, for typical connections between local display stations to the Web via network servers; any of which may be used to implement the system on which this invention is used. In the typical set up shown, terminals are connected via, let us say, host dial connections (not shown) to server 45 provided by a Web Service Provider or the private network service provider that in turn accesses the Web 50 via connection 51 to a Web access server 53 and connection 61 . In addition to the above-described standard dial-in or dial-out in the establishment of telephone conferencing, the Web or like browser program may be modified with application programs that will dial telephone stations. The possibility of such an alternate dialing is indicated in the lines connecting telephone stations 25 – 28 to their associated network terminals in addition to the lines connecting these telephone stations to the PSTN 23 .
With this Web network distributed monitoring set, there will now be described an embodiment for monitoring telephone conferences using the distributed Web page set up and monitoring panels of FIGS. 3 through 6 . The host who is setting up the teleconference uses the dialog panel of FIG. 3 to submit a profile of each attendee. At this point, we assume that the host has already cleared meeting times and scheduling with these attendees using conventional conference techniques such as those used in Lotus Notes, Version 6, Meetings and Conferencing. These procedures are not part of this invention that deals with the provision of monitoring panels. Thus, when the host is making entries on the set up dialog panel 70 of FIG. 3 , the subject and time of the meeting 79 has already been set. For each attendee 71 , the host enters the name 72 , the organization 73 , the telephone number 74 and whether the attendee is required 75 or optional 76 . The host is also prompted to enter a short biography 77 of the attendee. This information is stored at the host's display station or its associated network server. From this information, there is generated a Web page or panel 80 , FIG. 4 , that is distributed over the Web to all attendees for the conference at the time that dial in for the conference has been scheduled. The status shown in FIG. 4 is the Idle mode 85 wherein call-ins on the telephone stations have not yet commenced. Panel 80 has a set of circular icons 83 representing each required attendee and pentagonal icons 84 representing optional attendees. For each invited attendee, there is given the name 81 , as well a brief descriptive or biographical text. The conference itself is represented by icon 82 .
As the attendees begin to dial into the teleconference as shown in FIG. 5 , the connection of the attendee into the conference is indicated by a highlighting 86 , e.g. a lighting up or brightening of the icon representing the attendee. Also, during the initial call-in period, if all of the required attendees have not as yet called in, then the indicated conference status 85 changes to On-hold wherein the connected attendees need not wait on the line at the telephone. Rather, when the last required attendee calls in and is connected to complete the conference, then the telephones of all the on-hold attendees ring and the conference commences. This may be done automatically.
In FIG. 6 , the initiation of the conference is over; the status 85 is Active and the four required attendees are connected 86 . One of the optional attendees is connected 88 . As an aid to the attendees, when an attendee is speaking, his connected icon 86 flashes or pulses 87 . If any attendee disconnects during the conference, his icon will return to its initial unhighlighted state 83 ( FIG. 3 ).
FIG. 7 is a flowchart showing the development of a process according to the present invention for enabling telephone conference attendees to monitor such conferences over screen panels distributed to them over a communication network. In a private or public communication network, such as the Web, there is set up a system enabling the teleconference attendees to monitor by associating with each telephone station in the conference, a corresponding network display station for monitoring the teleconference, step 90 . The conference host is provided with a set up panel enabling him to designate optional and required attendees and provide a brief description of each attendee, step 91 . There is set up a process enabling the host to provide to each telephone conference attendee, a network, e.g. Web page describing each attendee, visually indicating whether the attendee is connected into the teleconference and whether the attendee is speaking, step 92 . A procedure is provided for teleconference initiation that enables the attendees to telephone conventionally into the conference and thereby be connected. The connection status of each attendee, according to step 92 , is indicated, step 93 . During the initiation period of step 93 , there is provided an on-call status wherein the connection status of each called-in and connected attendee is indicated but the attendee is free to do other functions until all required attendees are connected, step 94 . Finally, an implementation is provided for notifying all on-call attendees that a quorum of the required attendees has been reached in step 94 and for assembling all such attendees into the teleconference, step 95 .
A simplified run of the process set up in FIG. 7 and described in connection with FIGS. 3 through 6 will now be described with respect to the flowchart of FIG. 8 . The conference host is prompted and enters the data regarding attendees that is required to create the attendee monitoring screen panels, step 100 . The panels generated by the data entered by the host in step 100 is distributed to all attendees, step 101 . At the appointed time, initiation of the conference commences by standard telephone calls, step 102 . During conference initiation, a determination is made as to whether an attendee is connected, step 103 . If Yes, the attendee's icon on each monitoring panel is lit up, step 104 . Then, or if the decision in step 103 is No, a determination is made, step 105 , as to whether all required attendees have been connected, step 105 . If No, then, step 106 , all connected attendees remain on-call and the process is returned to step 103 . If Yes in step 105 , then the on-calls are assembled and the conference is begun, step 107 . During the teleconference, a determination is made as to whether an attendee is speaking, step 108 . If Yes, the speaking attendee's icon is flashed. Then, or if No, a determination is made as to whether a particular attendee has disconnected, step 110 . If Yes, the attendee's icon is turned off, step 111 . Then, or if No, a determination needs to be made as to whether the host has ended the conference, step 112 . If Yes, the conference is exited. If No, the process is returned to step 108 .
One of the preferred implementations of the present invention is in application program 40 made up of programming steps or instructions resident in RAM 14 , FIG. 1 , of Web server computers during various Web operations. Until required by the computer system, the program instructions may be stored in another readable medium, e.g. in disk drive 20 , or in a removable memory, such as an optical disk for use in a CD ROM computer input, or in a floppy disk for use in a floppy disk drive computer input. Further, the program instructions may be stored in the memory of another computer prior to use in the system of the present invention and transmitted over a Local Area Network (LAN) or a Wide Area Network (WAN), such as the Internet, when required by the user of the present invention. One skilled in the art should appreciate that the processes controlling the present invention are capable of being distributed in the form of computer readable media of a variety of forms.
Although certain preferred embodiments have been shown and described, it will be understood that many changes and modifications may be made therein without departing from the scope and intent of the appended claims.
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Monitoring of any conventional telephone conference in which a requisite set of conference attendees respectively at a corresponding set of telephone stations are connected into a telephone conference. In association with the telephone conference, a communication network with user access via a plurality of data processor controlled interactive display stations for displaying received network documents available from sources on the network in which there is an interactive display station associated with each of said set of telephone stations with a displayed document including an indicator representing each attendee having means for indicating whether the attendee's telephone station is connected into the conference, and means for indicating whether the attendee is speaking. During telephone conference initiation, there is placed on-call each telephone station initially connecting into the conference and there is an implementation for calling said on-call telephone stations into the conference when a quorum of said requisite attendees has connected into the conference.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefit of PCT Patent Application PCT/EP2008/003300 entitled “SHOE HAVING A SPRING POSITION LIMITATION, OR TORSIONAL OSCILLATION DAMPER HAVING SUCH A SHOE” and filed on Apr. 24, 2008, which claims benefit of German Patent Application 10 2007 022 891.2 filed on May 14, 2007.
BACKGROUND OF INVENTION
1. Field of Invention
The invention relates to a shoe having a spring-position limitation for use, in particular, in a torsional-vibration damper and to a torsional-vibration damper having end shoes and/or slide shoes designed on the basis of such shoe.
2. Description of Related Art
EP 1 584 839 A1 discloses a torsional vibration damper having a drive-input-side primary element which has at least one primary driver and having a drive-output-side secondary element which has at least one secondary driver, which primary element and secondary element can be rotated relative to one another about a neutral position counter to at least one spring element which is provided between one of the primary drivers and one of the secondary drivers, and having end shoes arranged on the end sides of the spring elements, with at least one of the end shoes being designed such that, when a threshold relative rotational angle with respect to the neutral position is reached, at least one of the drivers comes into direct contact with the spring element, bypassing the at least one end shoe.
Torsional vibration dampers or rotary vibration dampers are known in different variations and from different applications. They are provided in particular in automotive engineering for elastically coupling the internal combustion engine and drivetrain. In this way, it is sought to prevent vibrations from being transmitted from the internal combustion engine to the drivetrain or gearbox. Such a transmission of vibrations occurs in motor vehicle drives in particular in the case of internal combustion engines with comparatively few cylinders and at low rotational speeds. Effective damping of such vibrations makes it possible for the internal combustion engine to be operated at relatively low rotational speeds, which generally entails a reduced fuel consumption and is therefore both economically and ecologically advantageous.
Torsional vibration dampers having a drive-input-side primary element and a drive-output-side secondary element which are coupled to one another by means of a spring device and which are rotatable with respect to one another to a limited extent about a rotational axis are known for example from EP 1 371 875 A1 or DE 195 22 718 A1. The primary element comprises a first driver which will also be referred to below as the primary driver. The secondary element comprises a second driver which will also be referred to below as the secondary driver. The torque is transmitted from the primary element by means of the primary driver firstly to the spring device and from there to the secondary driver of the secondary element.
The spring device is generally composed of one or more spring elements arranged in series in the circumferential direction of the torsional vibration damper, preferably helical springs or helical spring sets which are if appropriate connected to one another by means of slide shoes and are supported at both end sides by means of end shoes against the respective driver. If a transmission of torque takes place from the primary element to the secondary element, the described transmission of torque is referred to as traction. If, in contrast, the transmission of torque takes place in the opposite direction from the secondary element to the primary element, this is referred to as overrun.
It has been found that, in the event of a traction/overrun shift, in particular under low load conditions, a changeover noise can be heard. This can be attributed to the fact that, during the traction/overrun shift, the drivers of the primary and secondary elements abut against the end shoes which support the spring elements, and this can cause the changeover noise mentioned.
For this reason, in DE 101 33 694 A1, additional spring elements were provided between the end shoes and the drivers in order to reduce the abutment of these against one another and the associated generation of noise.
In contrast, in DE 199 58 814 A1, such additional spring elements are dispensed with and, instead, the end shoe which bears against the end side of the respective spring element is designed so as not to completely cover the end side of the spring element. Furthermore, the drivers are provided with an arm which is designed such that, in the event of an abutment of the driver and end shoe against one another, the arm of the driver firstly abuts directly against the spring element, bypassing the end shoe. In this way, the movement of the driver is initially damped slightly before the driver abuts over a large area against the end shoe, such that the abovementioned changeover noises can be reduced at least in the event of small torques to be transmitted. A disadvantage of the device is that the initial damping effect is not great enough if the driver is acted on with a high rotational impetus or a high torque. In this case, changeover noises are still generated as the driver abuts against the stop.
Generally known from EP 0 236 159 is a torsional vibration damper in which use is made of two differently-dimensioned types of springs, with the first of the springs being connected in each case alternately in series with the second of the springs.
DE 102 40 839 A1 discloses a torsional vibration damper in which, within the windings of a first spring, a second spring with a smaller outer diameter is inserted. Here, the second spring projects at the end side slightly out of the end side of the first spring. Here, the two springs are mounted in each case entirely within a common end stop, such that undesirable noises are generated in the event of an abutment of a driver.
DE 199 09 044 A1 describes a further arrangement of a torsional vibration damper of this type, with the second spring having, in its central section, a spring winding with an increased diameter, which spring winding engage between two adjacent spring windings of the first, outer spring and thereby fix the second spring in the first spring. In this arrangement, the second, inner spring is dimensioned so as to be harder than the outer spring. The two springs are again mounted at the end side on in each case one end stop or driver.
DE 100 19 873 A1 describes a torsional vibration damper having a multiplicity of springs which are mounted in slide shoes. Here, partially differently dimensioned first and second springs alternate in the circumferential direction.
DE 41 41 723 C2 describes a torsional vibration damper having an idling spring system. In this arrangement, too, differently dimensioned springs are inserted in the circumferential direction.
The problem on which the invention is based is that of proposing, in a simple manner, a shoe having a spring position limitation and having two springs which are arranged one inside the other, such that improved isolation and vibration damping can be realized. Furthermore, it is sought to propose a torsional vibration damper using a shoe of this type in the form of end shoes and/or slide shoes.
SUMMARY OF INVENTION
The present invention overcomes the disadvantages in the related art in a shoe that mounts an outer spring defining a longitudinal direction and an inner spring arranged within the outer spring. The outer and inner springs define corresponding end sides of the outer and inner springs, and the shoe defines an end side of the shoe. A spring-position limitation limits the outer spring in its longitudinal direction and enables the inner spring to emerge at the end side of the shoe out of the outer spring. A driver primary element exerts a pressure on the inner spring as the driver approaches the outer and inner springs in a direction of the corresponding end sides of the outer and inner springs.
It is preferable for the spring position limitation to form a spring rest surface for providing support facing toward that portion of the second, inner spring which projects out of the first, outer spring. In this way, a radial support of the second, inner spring when inserted in a torsional vibration damper is formed by the spring position limitation for the first spring.
The spring rest surface preferably has, for the second, inner spring, a curved profile with a radius of at least that of the outer circumference of the second, inner spring. In this way, the second, inner spring is not only provided with hold in the radial direction but is also provided with hold in the lateral direction with respect to the radial direction. The second, inner spring is preferably longer than the first, outer spring.
The second, inner spring advantageously has a smaller outer circumference than an inner circumference of the first, outer spring. In this way, the second, inner spring can be compressed by at least such a distance into the first, outer spring that the driver firstly pushes the second, inner spring into the first, outer spring before the driver compresses both the first, outer spring and the second, inner spring together.
The second, inner spring is preferably softer than the first, outer spring. Such dimensioning permits an initially particularly soft damping action which increases with progressive travel of the driver and experiences further, more intense damping upon abutment additionally against the first, outer spring. An abrupt braking or abutment of the driver against a spring arrangement having a uniform and abruptly increasing damping effect is thereby particularly advantageously avoided.
In a spring arrangement having one or more spring sets, at both end sides of the spring arrangement, the first, outer spring is preferably limited by spring position limitations and the second, inner spring preferably projects at both sides out of the end sides of the first, outer spring. In such an arrangement, additional slide shoes are if appropriate positioned in between in order to support such spring arrangements.
End-side ends of the second, inner spring or springs are preferably unloaded in a neutral position. In an idling position, therefore, those ends of the second, inner springs which project out of the end sides of the first springs are preferably not acted on with force, such that, with a change in a torque acting in the torsional vibration damper, soft damping can introduce a torque shift regardless of the torque direction. A retaining device advantageously fixes both the first, outer spring and the second, inner spring to the end shoe or slide shoe and relative to the same at a distance from the at least one spring position limitation.
Both the first, outer spring and the second, inner spring may be fixed to two slide shoes by means of two retaining devices which are at a distance from one another and from the spring ends of the springs, with the slide shoes being freely adjustable with respect to one another by means of a slide surface. Such an arrangement permits the arrangement of to arrange two springs and/or a plurality of spring sets with two outer springs designed in this way in particular a torsional vibration damper for an elongated damping path between two end shoes. Here, it is also Possible if appropriate for even the slide shoes to be designed as end shoes.
A further spring position limitation may advantageously be formed on the shoe to limit the end-side spring travel of the second, inner spring. Here, the further spring position limitation is preferably arranged, for the second, inner spring, on the spring rest surface of the spring position limitation for the first, outer spring.
The spring position limitation preferably has a continuous recess for allowing the driver to extend through against the end sides of the second, inner spring and the first, outer spring. This advantageously permits a limitation of the spring extent either for the first spring or for both springs, and nevertheless permits a low-noise or noise-preventing abutment of the driver which moves against the end sides of the springs. The first, outer spring preferably has play in its axial extent between the spring position limitation and a spring retaining device which is spaced apart therefrom, with the first, outer spring being supported on a spring rest surface.
The first, outer spring and the second, inner spring may be fixed to one another and/or to the shoe at different distances from the spring position limitation. This permits an optimum setting of the spring travels of the first and of the second spring, and also makes it possible for the entire spring arrangement to be optimally adapted to respective given conditions.
According to an independent advantageous embodiment, the travel of the first, outer spring is restricted by a spring position limitation while the travel for the extent of the second, inner spring is permitted over a longer extent, such that the second, inner spring can project at the end side out of the first, outer spring. Here, an embodiment is advantageous in which the spring position limitation for the first, outer spring is simultaneously formed as a spring support for the second, inner spring.
The torsional vibration damper is preferably provided with end shoes which are designed so as to also provide guidance for the spring elements, but so as not to come into direct contact with the associated driver at any time during the damping process; the driver rather instead always abuts directly preferably against the end side of the respective spring element. Here, the spring elements dampen the abutment movement of the driver, such that no changeover noises occur regardless of the rotational impetus of the driver.
One advantageous refinement of the invention consists in providing the at least one end shoe with at least one device which enables the end shoe to be fastened to the spring element. The device is preferably embodied as a retaining lug, by means of which windings of at least one helical spring of the associated spring element can be clamped. In this way, the end shoe is prevented from being released from the spring element during damping operation, which would cause the spring element to lose its guidance. If the spring element is composed of a plurality of different helical springs arranged one inside the other, it is possible in particular for fastening devices to be provided which connect the end shoe to different helical springs.
An end shoe of this type is optionally designed such that the at least one driver remains in direct contact with the spring element for as long as the threshold relative rotational angle is exceeded. The corresponding driver may alternatively or additionally also optionally be designed such that the at least one driver remains in direct contact with the spring element for as long as the threshold relative rotational angle is exceeded. Consequently, a transmission of torque always takes place from the driver to the spring element, in contrast to DE 199 58 814 A1, where a transmission of torque from the driver to the end shoe and from the end shoe to the spring element takes place above a threshold relative rotational angle.
What is preferable is a torsional vibration damper having shoes of this type, a drive-input-side primary element, which has at least one primary driver, and a drive-output-side secondary element, which has at least one secondary driver. The primary element and secondary element can be rotated relative to one another about a neutral position counter to at least one spring element that is provided between one of the primary drivers and one of the secondary drivers. The torsional vibration damper has also end shoes arranged on the end sides of the respective spring element. At least one of the end shoes is designed such that, when a threshold relative rotational angle with respect to the neutral position is reached, at least one of the drivers comes into direct contact with the spring element, bypassing the at least one end shoe. The at least one end shoe and/or the at least one driver is designed such that the at least one driver remains in direct contact with the spring element for as long as the threshold relative rotational angle is exceeded.
Other objects, features, and advantages of the present invention will be readily appreciated as the same becomes better understood while reading the subsequent description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF EACH FIGURE OF DRAWING
The invention will be explained in more detail below on the basis of figures. Identical or functionally identical components are provided with the same reference numerals in all the figures, in which:
FIG. 1 schematically shows a partially sectioned side view of a shoe for a torsional vibration damper in order to illustrate the basic principle,
FIG. 2 shows the arrangement from FIG. 1 in a front view,
FIG. 3 shows a side sectional view of an exemplary shoe within a torsional vibration damper,
FIG. 4 shows a sectional view in the circumferential direction through a torsional vibration damper with a view of the end side of a shoe,
FIG. 5 a shows an illustration of the basic principle of another preferred embodiment of the torsional vibration damper of the present invention shown in its neutral position,
FIG. 5 b shOws an illustration of the basic principle of the embodiment of the torsional vibration damper illustrated in FIG. 5 a shown under a slight tractive load,
FIG. 5 c shows an illustration of the basic principle of the embodiment of the torsional vibration damper illustrated in FIG. 5 a shown under a full load,
FIG. 6 shows the torsional vibration damper according to FIG. 1 in an exploded illustration, and
FIG. 7 shows a detail of an exemplary torsional vibration damper having end shoes.
DETAILED DESCRIPTION OF INVENTION
FIGS. 6 and 7 illustrate a torsional vibration damper 3 having a primary element in the form of a central disk 26 and having a secondary element in the form of two side disks 24 , 25 which are rotationally fixedly connected to one another. Spring elements composed of a plurality of spring sets 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 are arranged around the central disk 26 in a cavity formed by the rear side disk 24 and by the front side disk 25 . In the present exemplary embodiment, each of the spring sets 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 is composed of two helical springs situated one inside the other; a first, outer spring 1 and a second, inner spring 2 . The spring sets 5 , 6 , 7 , 8 , 9 , 10 and 11 , 12 , 13 , 14 , 15 , 16 respectively are arranged in series, so as to form in each case one spring element, by means of spacers, so-called slide shoes 28 , 29 , 30 , 31 , 32 and 33 , 34 , 35 , 36 , 37 respectively. An end shoe 18 a , 18 b , 18 c , 18 d is arranged on the respective end of a spring element.
The end surfaces of the end shoes 18 a , 18 b , 18 c , 18 d are seated, in a neutral position, in each case on a driver 17 a , 17 a ′; 17 b , 17 b ′, which is formed in two parts here, of the secondary element 24 , 25 which is composed of two side disks 24 , 25 . The end shoes 18 a , 18 b , 18 c , 18 d are of U-shaped design at their end sides. Here, the two limbs of the U-shape are seated in a substantially positively locking manner on the respective driver, composed of the two driver parts 17 a , 17 a ′ and 17 b , 17 b ′, of the secondary element.
The intermediate space between the two limbs of the U-shape of the respective end shoe 18 a , 18 b , 18 c , 18 d is selected to be precisely so large that the driver 19 b of the primary element 26 , in the event of a relative rotation between the primary and secondary elements 24 , 25 , 26 in one rotational direction, abuts directly against the spring set 14 without coming into contact with the end shoe 18 b . At the same time, the driver 19 a of the primary element 26 abuts directly against the spring set 10 without coming into contact with the end shoe 18 c.
In the event of a relative rotation between the primary and secondary elements 24 , 25 , 26 in the other rotational direction, the driver 19 b of the primary element 26 abuts directly against the spring set 5 without coming into contact with the end shoe 18 a . At the same time, the driver 19 a of the primary element 26 abuts against the spring set 11 without coming into contact with the end shoe 18 d . This measure serves to prevent the generation of changeover noises.
It can also be seen from the drawing that the respective end shoes 18 a , 18 b , 18 c , 18 d have, on the outer circumference, slide surfaces 27 a , 27 b , 27 c , 27 d which are supported against the inner wall of a cylindrical region of one of the side disks 24 (or 25 ). The slide shoes 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 are also designed in the same way as the end shoes 18 a , 18 b , 18 c , 18 d . The slide shoes 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 are also supported at the outer circumference against the inner wall of the cylinder of the corresponding side disk 24 (or 25 ).
The slide surfaces 27 a , 27 b , 27 c , 27 d of the end shoes 18 a , 18 b , 18 c , 18 d and the slide surfaces, which are not provided with reference symbols, of the slide shoes 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 firstly ensure that the spring sets 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 are compressed with low friction and without misalignment when the primary and secondary elements 24 , 25 , 26 are rotated with respect to one another. Furthermore, in the present exemplary embodiment, the circumferential extent of the end shoes 18 a , 18 b , 18 c , 18 d and of the slide shoes 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 is dimensioned such that their end surfaces which face toward one another come into abutting contact before the individual helical springs of the spring sets 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 reach the blocked state. The end shoes 18 a , 18 b , 18 c , 18 d and the slide shoes 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 therefore define the maximum compression α of the spring sets 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 . This measure serves to prevent the helical springs from being destroyed at high torques.
FIGS. 1 and 2 show a particularly preferred embodiment of an exemplary end shoe 18 . Reference symbols which have been described with regard to the embodiment described above will not be explained in any more detail below; reference is made to the statements made above.
The exemplary end shoe 18 has a shoe body 40 which has a spring rest surface 41 on the upper side, which spring rest surface 41 serves to laterally mount and radially support the first, outer spring 1 . Here, the spring rest surface 41 may preferably have a curvature corresponding to the outer curvature of the first, outer spring 1 . In a preferably end-side region, a spring position limitation 42 is fastened to or formed in one piece with the shoe body 40 . The spring position limitation 42 projects away from the spring rest surface 41 in the direction of the upper side, that is to say in the direction of the first, outer spring 1 which lies thereon, to such an extent that the spring position limitation 42 forms an end-side stop for the first, outer spring 1 . Here, a height h of the spring position limitation 42 for the first, outer spring 1 is selected such that the second, inner spring 2 can project out of the first end side 43 , which bears against the spring position limitation 42 , of the first, outer spring and, with its end side 44 of the second, inner spring 2 , is not limited by the spring position limitation 42 for the first spring.
The shoe body 40 may optionally also additionally have, at the outer side or end side, a further spring position limitation 45 for the second, inner spring 2 . In this way, the latter is also limited at the end side and can extend with its first end side 44 only up to the further spring position limitation 45 .
Both the spring position limitation 42 for the first, outer spring 1 and also the further spring position limitation 45 for the second, inner spring 2 have a recess 46 which extends all the way through the body of the spring position limitations 42 , 45 and enables a driver 19 b to press against the end sides 44 , 43 of the second, inner spring 2 and preferably also of the first, outer spring 1 through the recess 46 . By means of such a design, in which the second, inner spring 2 projects at the end side out of the first, outer spring 1 , the driver 19 b presses firstly against the first end side 44 of the second, inner spring 2 and only subsequently against the first end side 43 of the first, outer spring 1 . This generates an initially lightly damped braking of the driver 19 b and a more intense braking of the driver 19 b only at a later time, or from the point of view of a slidable end shoe 18 , firstly a slow acceleration and then an increasing acceleration. At the rear side, or in a central section, the end shoe 18 has a spring retaining device 47 which projects therefrom in the direction of the springs, which spring retaining device 47 , for example as a mandrel-like projection, is guided between individual windings of the first, outer spring 1 and the second, inner spring 2 . In this way, the two springs 1 , 2 are connected to the end shoe 18 in an immovable fashion in the region of the spring retaining device 47 . The springs 1 , 2 may however also be merely supported at the rear side by the spring retaining device 47 .
The two springs 1 , 2 may be configured individually depending on the desired action and desired field of use. It is particularly preferable to use a soft second, inner spring 2 in relation to a relatively hard first, outer spring 1 . In principle, however, the spring parameters may be selected to be identical or even reversed. Instead of the second, inner spring 2 likewise being fixed to the end shoe 18 by means of the spring retaining device 47 at the same position as the first, outer spring 1 , the second, inner spring 2 may also be fixed relative to the first, outer spring 1 at some other position. In such a case, it is for example possible for a winding of the second, inner spring 2 with a relatively large circumference to engage between corresponding windings of the first, outer spring 1 .
According to further embodiments, the second, inner spring 2 may project not only out of the first end side 43 of the first, outer spring 1 but rather also out of the opposite, second end side of the first, outer spring 1 . Such an embodiment may in particular be provided not only in the form of an end shoe 18 but rather also in the form of a slide shoe 28 . The surface of the spring position limitation 42 for the first spring 1 is preferably formed with a surface curvature corresponding to the outer circumference of the second, inner spring 2 , such that the surface forms a spring rest surface 48 for the second, inner spring 2 .
FIG. 3 shows an example of a slide shoe 50 which is inserted in a torsional vibration damper. Again, the first end side 44 of the second, inner spring 2 projects out of the first end side 43 of the first, outer spring 1 . At the opposite end, both springs 1 , 2 bear against a spring retaining device 47 which serves to limit the springs 1 , 2 . In this embodiment, only a spring position limitation 42 for the first, outer spring 1 is arranged on a shoe body 40 . The exemplary slide shoe 50 has a slide surface 53 which corresponds to a curved profile corresponding to the curvature of the corresponding inner guide surface of a secondary element 25 . The illustration of FIG. 3 also shows axial openings 54 in the side disk.
FIG. 4 shows a section through the torsional vibration damper illustrated in FIG. 3 along the line “A-A.” FIG. 5 shows, in a side view, an operating principle of a first, outer spring 1 and of a second, inner spring 2 which are mounted by means of two slide shoes 52 on a slide surface 53 . Here, an independent spring set composed of an outer and an inner spring, or if appropriate also only a single individual spring, may be arranged between the two slide shoes 52 . In such a case, separate spring sets composed of a first, outer spring 1 and a second, inner spring 2 are arranged at the outsides of the two slide shoes 52 , with the two second, inner springs 2 projecting at the end side out of the first, outer springs in an unloaded position.
For exerting a load on the outer end sides, drivers 19 a , 19 b are also depicted which are arranged with a constant spacing with respect to one another and which, in a neutral position, bear against the two outer end sides of the arrangement of springs 1 , 2 . Here, the two second, inner springs 2 preferably project slightly out of the end sides of the two first, outer springs 1 , as depicted in the uppermost illustration. The first, outer springs 1 are situated between the driver secondary elements 17 a , 17 b . The central illustration illustrates the situation of slight tractive load, in which the driver 19 b depicted at the right-hand side exerts a compressive force on the outer end side of the second, inner spring 2 , which compressive force is then ultimately transmitted to the entire spring arrangements and slide shoes 52 and to the drivers 17 a , 17 b of the secondary element. On the opposite side of the arrangement, at which the opposite, second driver 19 a moves away from the spring arrangement, the outer spring 1 is supported at the end side against the driver 17 a of the secondary element, and the inner spring 2 protrudes, unloaded, through the driver 17 a of the secondary element. The lower figure depicts the situation of full load, in which both the end side of the second, inner spring 2 and also the end side of the first, outer spring 1 are acted on with force by the driver 19 b arranged at the right-hand side. Such a mode of operation can be used not only in a torsional vibration damper with a correspondingly curved slide surface, but rather in principle also in situations with a planar slide surface 53 , as depicted in FIG. 5 .
A shoe according to the above embodiments is therefore preferably designed in particular as a slide shoe (skate) with an inner spring rest and spring position limitation. Here, the shoe serves to provide support and to deflect spring forces.
In a torsional vibration damper in particular, the shoe geometry is selected such that the unloaded first, outer spring 1 , in its free length, is inserted in the shoe with slight play between the spring retaining device 47 and the spring position limitation 42 . In this way, slipping out can be prevented, such that the spring 1 does not move away from the shoe in the circumferential direction. Here, the circumferential direction is to be understood to mean a tangential or concentric direction about a central rotational axis of the torsional vibration damper.
The second, inner spring 2 which projects in the circumferential direction is preferably longer, in the unloaded state, than the first, outer spring 1 . The second, inner spring 2 which projects at the end side out of the first, outer spring 1 can be supported or can rest with its projecting section preferably on the spring position limitation 42 for the first, outer spring 1 . It is optionally possible for a further spring position limitation 45 for the second, inner spring 2 to be formed on the shoe, for example on the end shoe 18 . The spring position limitations 42 , 45 have a cutout or recess 46 which is dimensioned so as to enable the driver 19 b or a portion, which projects from the driver 19 b in the direction of the end sides 43 , 44 of the springs 1 , 2 , to pass through. In this way, a flange vane of a driver 19 b of this type can pass, during its rotational movement, through the spring position limitation 42 , 45 and thereby actuate firstly the relatively long second, inner spring 2 and subsequently the second, inner spring 2 and the first, outer spring 1 . The second, inner spring 2 preferably has a lower spring rate than the first, outer spring 1 .
The dimensions of the shoe in the form of an end shoe 18 or slide shoe and the dimensions of the primary element and secondary element are preferably coordinated with one another in such a way that the shoe, with its spring position limitation, can pass the stops of the primary element and/or of the secondary element without making contact. The flange vane or driver 19 b is preferably narrower than the corresponding spring stops in the primary and secondary masses.
Embodiments with different dimensions and arrangements are alternatively possible. For example, in the event of the first, outer spring and the second, inner spring being of approximately equal length in the unloaded state, the shoe may also be formed with only the spring position limitation, with a radial spring support being dispensed with.
As well as permitting a neutral position, such an arrangement also permits, in advantageous embodiments, in particular low-load states and load shift transitions, as is also depicted in FIG. 5 . In the low-load states, in which only the second, inner springs 2 of a torsional vibration damper are actuated, improved isolation or vibration damping is realized by means of the “soft” inner spring with, for example, a low pitch. The transition torque at which the driver moves from abutting against only the second, inner spring 2 to also abutting against the first, outer spring 1 can be adapted corresponding to the desired behavior. In particular, since it is possible for the inner springs which are seated in the end springs to protrude through the spring stops, any possibly occurring noise which could be caused by the abutment of the spring against the spring stops is reduced in certain situations.
In the case of an arrangement of a slide shoe with an inner spring rest and spring position limitation in the form of the spring position limitation 42 for the first, outer spring 1 according to FIG. 1 both on the traction side and also on the overrun side, a functional advantage is obtained for the overrun. In traction without preload, that is to say without spring actuation, the second, inner spring 2 of the overrun-side slide shoe is pushed between the stops of the primary and secondary masses of the torsional vibration damper. During the subsequent shift to overrun, the overrun-side actuated second, inner spring, which projects in the unloaded state, is very soft and can perform an isolation or damping function in an unhindered manner.
At idle or in the neutral position ( FIG. 5 ), the flange vane or driver can oscillate between the two soft second, inner springs 2 of the end spring pack. In this way, it is possible to realize improved isolation or vibration damping. Since the unloaded springs are placed between two limiting contours in the slide shoe or end shoe, that is to say between a slide shoe wedge in the form of a spring retaining device 47 and a spring position limitation 42 , 45 , the springs 1 , 2 cannot slip out of the slide shoe or end shoe 18 in the circumferential direction.
The end shoe may optionally be formed with stop lugs as the spring position limitation, which stop lugs form abutment points for the end surface of the associated spring element. The stop lugs prevent the spring element from sliding forward with its end side through the end surface of the end shoe, and prevent the spring element from thereby losing its guidance.
The present invention has been described in an illustrative manner. It is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described.
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A shoe mounts an outer spring defining a longitudinal direction and an inner spring arranged within the outer spring. The outer and inner springs define corresponding end sides of the outer and inner springs, and the shoe defines an end side of the shoe. A spring-position limitation limits the outer spring in its longitudinal direction and enables the inner spring to emerge at the end side of the shoe out of the outer spring. A driver primary element exerts a pressure on the inner spring as the driver approaches the outer and inner springs in a direction of the corresponding end sides of the outer and inner springs.
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FIELD OF THE INVENTION
[0001] The present invention relates to the field of insulation and thermal barriers, and, more particularly to a method for forming a multi-layer, nonwoven fiberglass insulating mat, and the mat formed therefrom.
BACKGROUND OF THE INVENTION
[0002] In recent years, needled nonwoven textile fabrics have become increasingly popular. Needled nonwovens are created by mechanically orienting and interlocking the fibers of a spunbond or carded web or batt. In particular, numerous needled or felted fabrics have been formed of either natural or synthetic fibers, or both; however, inorganic fibers such as glass fibers, are not normally suitable for felting or needling because glass fibers are quite brittle and do not lend themselves to being carded, needled, or felted. They are typically consolidated by either an air lay or wet lay process into a fabric having generally poor physical properties.
[0003] More recently, the desire to make thicker (1 inch or greater), lower weight basis, and lower density (less than about 5 pounds per cubic foot) insulating (thermal or acoustical) mats has created a renewed interest in needle punching of fiberglass fibers. In one process, e-glass fibers were opened, formed into a thick batt, and mechanically bonded on a needle loom in a single pass to form a mat. Unfortunately, these mats still have a density of 6 to 12 pounds per cubic foot.
[0004] Most recently, fiberglass fibers have been bonded together by resinous binders or thermoplastic adhesives to form thicker mats. Resinous binders, however, create undesirable problems with outgassing, and most contain either phenolic or melamine formaldehydes, which are environmentally and occupationally undesirable.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to a new needle punching method for producing thicker, lightweight insulating mats from fiberglass fibers, and to an insulating mat so formed which addresses and overcomes the previous problems.
[0006] Thus, one aspect of the present invention is directed to a method for forming a thicker (greater than 1 inch), lower weight basis, and lower density (about 4 pounds per cubic foot) insulating mat.
[0007] As a first step in the process, a first loose batt of fiberglass fibers is needle punched to form a relatively thin, relatively dense first layer. In one embodiment, the fiberglass fibers are e-glass. A second layer is next similarly formed by needle punching a second loose batt of fiberglass fibers. An intermediate batt of similar fiberglass fibers is then fed between the first and second layers to form a relatively thicker and less dense middle layer. The first layer, intermediate batt, and second layer are lastly needled together in a single pass to form a three-layer (lower, middle, and upper) insulating mat. As a result, the outer layers (lower and upper) are more dense and provide the integrity and strength of the overall construction and good surface quality. The first and second layers are more dense since the fiberglass fibers forming the batts are needle punched with a large number of needle punches per square inch and with deeper penetration depth into more compact layers. The intermediate layer is less dense and substantially provides the overall thickness since the final needle punching step is performed with a much lower number of punches per square inch and much less penetration depth. Further, fewer punches per square inch in the final needle punching step are required to interlock the first and second layers to the intermediate layer.
[0008] In an exemplary embodiment, the densities of each of the lower and upper layers are substantially equal, but greater than the density of the middle layer.
[0009] Another aspect of the present invention is directed to a multi-layer nonwoven insulating mat formed in accordance with the method described herein.
[0010] These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiments when considered in conjunction with the drawings. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a prior art nonwoven insulating mat formed from a single thick batt of fiberglass fibers.
[0012] FIG. 2 is a flow diagram of the method of the present invention.
[0013] FIG. 3 illustrates one embodiment of the insulating mat formed in accordance with FIG. 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Referring to the Figures in general, the present invention is directed to a method for producing a multi-layer nonwoven insulating mat of fiberglass fibers, and to an insulating mat so formed.
[0015] “Needle punching” refers to the process of converting batts or webs of loose fibers into a coherent fabric, referred to as a nonwoven fabric, on a needle loom. Needle punched nonwovens are created by mechanically orienting and interlocking the fibers of a batt, as those terms are known in the art. The mechanical interlocking is achieved with a large number of barbed felting needles that repeatedly punch through a loose batt.
[0016] The generic needle punch loom comprises at least one needle board that is held in place by a needle beam. Feed rollers and exit rollers are driven to move the batt of fiberglass fibers through and out of the needle loom. A bed plate and stripper plate each have a plurality of holes (not shown) that correspond to the pattern of felting needles that are mounted on the needle board. The bed plate permits the needles to pass completely thorough the batt, while the stripper plate strips the fibers from the needles as they are retracted upwardly or downwardly so that the material can pass through the loom.
[0017] The needle loom used to practice the present invention is a Model NL9/SRS, available from Fehrer of Austria. This particular needle loom has upper and lower needle boards and stripper plates; however, other needle looms capable of providing comparable mechanical interlocking of the fiberglass fibers, as described in greater detail below, may be used.
[0018] To mechanically interlock the fibers in each fiberglass batt, a drive (not shown) moves the needle boards upwardly and downwardly with the plurality of needles mounted thereon passing through the stripping and bed plates. As those skilled in the art will appreciate, the correct “felting” needles must be selected for interlocking the fibers, without damaging or breaking, the fiberglass fibers. For the method of the present invention, 15×18×25 needles are employed, but other needle geometries may also be used.
[0019] As those skilled in the art will appreciate, the primary variables affecting the effectiveness of the needling process include the depth of penetration and the concentration and pattern of the felting needles. The greater the depth of penetration, the greater the entanglement of fibers within the batt. The greater the number/concentration of punches to the batt, the more concentrated is the entanglement pattern and the more dense is the resulting batt. The degree of entanglement is dependent upon the number of needles/punches per square inch, the rate of the batt feed to the loom, the punching frequency (upwardly and downwardly speed of the needle boards), and the number of passes of the batt through the loom. These variables will be described in greater specificity in the Examples below.
[0020] The fibers used in the exemplary embodiments described herein are created from a preferred feed stock (yarns formed from continuous fibers) that is between ECG-37 and ECG-75, but ECE-225 to ECK-18 may also be used, as those categories of material are known in the art. The feed stock is first chopped into staples having lengths of about 3 inches long; however, staples between about 2 inches and 4 inches are also suitable. In one embodiment, the fibers comprising the yarn are about 9 microns in diameter, but diameters of between 5 microns and 13 microns are suitable. E-glass staple fibers are available from several vendors such as PPG, St. Gobain, and AGY. E-glass is particularly suitable because it can withstand temperatures up to about 1,200 degrees Fahrenheit. For higher temperature applications, silica glass fibers (available from BGF Industries, Inc. of Greensboro, N.C.) may be used. Silica glass fibers can withstand temperatures up to about 2,000 degrees Fahrenheit.
[0021] Turning now to FIGS. 2 and 3 , a simplified flow diagram of the process 200 and product 300 of the present invention is shown. The process begins with opening (Step 205 ). Opening is a preliminary operation in the processing of staple fibers. Opening separates the compressed masses (bales) of fiberglass staples into loose tufts. In the embodiments described herein, a Rando Opener Blender (ROB), available from Rando Company of Rochester, N.Y. is used. The open fiberglass fibers are next formed into a loose batt (Step 210 ) on a Rando Webber, also available from Rando, in preparation for the needle punching operation. A feed belt is set to run at a specified speed, whereupon loose fiberglass fibers are deposited on the belt to obtain a desired thickness and density. The loose batt so formed is between approximately 2 inches and 4 inches in thickness, depending upon the desired final thickness of the finished multi-layer mat.
[0022] The loose batt is fed through the needle loom to form a first layer 310 (Step 215 ). The batt is fed at a speed of between about 14 feet per minute and 18 feet per minute, and desirably at a speed of about 16 feet per minute. As the batt passes beneath the needle board, the needles punch the batt at between 500 punches per square inch (PPSI) and 600 PPSI. As discussed above, and as will be appreciated by those of ordinary skill in the art, there are various feed rate and punching rate combinations that will yield a suitable puncture density.
[0023] The process for forming a second layer 320 (Step 220 ) is similar to the process for forming the first layer, unless a different thickness, weight basis, etc. are desired. In each of the embodiments described herein, the puncture density of the first and second layers creates denser layers, thus enhancing the integrity and tensile strength of the these layers.
[0024] Following formation of rolls of the first and second layers, rolls of the first and second layers/mats are simultaneously fed to the needle loom as the lower and upper layers, while a loose batt of opened e-glass fibers 330 between about 4 inches and 6 inches thick is inserted between the two layers (Step 225 ). All three layers are simultaneously needled together (Step 230 ) at a speed of between about 7 feet per minute and 18 feet per minute, and desirably at a speed of about 12 feet per minute with punches 340 from needles 160 at between about 150 PPSI and 250 PPSI. The finished mat is then taken up on rolls (Step 235 ) for further processing, storage, or shipment. The final multi-layer nonwoven mat so formed may have a width of up to about 96 inches.
[0025] Depending upon the application for which the nonwoven insulating mat is intended, e.g., water heater insulation, the final thickness and weight basis of each layer may be varied when formed in accordance with the process of the present invention. The following are exemplary embodiments for multi-layer insulating mats having total thicknesses between one inch and two inches:
EXAMPLE 1
[0026] For an insulating mat with a final thickness of about one inch, the first layer begins with a loose batt of e-glass staple fibers that is about 2 inches thick. The loose batt is subjected to needle punching with a puncture density of between about 500 PPSI and 600 PPSI to produce a relatively dense layer having a thickness of about 0.125 inches, a weight basis of about 1 ounce per square foot, and a density of about 6 pounds per cubic foot. In this embodiment, the first and second, or lower and upper, layers are formed in the same manner so that they have the same thickness, weight basis, and density, although they may be formed differently for a particular application.
[0027] Rolls of the first and second layers/mats are simultaneously fed to the needle loom as the lower and upper layers, while a loose batt of opened e-glass fibers are inserted between the two layers. This loose e-glass intermediate, or middle, layer has a thickness of about 4 inches as it is inserted between the lower and upper needled layers.
[0028] All three layers are subjected to a needling puncture density of 175 PPSI at a desired penetration as each of the first and second layers were previously penetrated. In effect, then, the lower and upper layers are each needle punched twice.
[0029] Following the needle punching of the three-layer construction, the upper and lower layers each have a thickness of approximately 0.125 inches, a weight basis of about 1.0 ounces per square foot, and a density of about 6.0 pounds per cubic foot. The intermediate layer is approximately 0.75 inches thick (approximately 6 times the thickness of each of the upper and lower layers), with a weight basis of about 3.3 ounces per square foot, and a density of about 3.3 pounds per cubic foot (approximately 55 percent of the density of each of the upper and lower layers). The resulting multi-layer insulating mat then has a combined thickness of about 1 inch, an average weight basis of about 5.3 ounces per square foot, and an average density of about 4 pounds per cubic foot.
EXAMPLE 2
[0030] For an insulating mat with a final thickness of about 1.25 inches, the first layer begins with a loose batt of e-glass fibers that is about 2.5 inches thick. The loose batt is subjected to needle punching with a puncture density of between about 500 PPSI and 600 PPSI to produce a relatively dense layer having a thickness of about 0.16 inches, a weight basis of about 1.3 ounces per square foot, and a density of about 6 pounds per cubic foot. In this embodiment, the first and second, or lower and upper, layers are formed in the same manner so that they have the same thickness, weight basis, and density, although they may be formed differently for a particular application.
[0031] Rolls of the first and second layers/mats are simultaneously fed to the needle loom as the lower and upper layers, while a loose batt of opened e-glass fibers are inserted between the two layers. This loose e-glass intermediate, or middle, layer has a thickness of about 4.5 inches as it is inserted between the lower and upper needled layers.
[0032] All three layers are subjected to a needling puncture density of 175 PPSI at a desired penetration as each of the first and second layers were previously penetrated. In effect, then, the lower and upper layers are each needle punched twice.
[0033] Following the needle punching of the three-layer construction, the upper and lower layers each have a thickness of approximately 0.16 inches, a weight basis of about 1.3 ounces per square foot, and a density of about 6.0 pounds per cubic foot. The intermediate layer is approximately 0.93 inches thick (approximately 5.8 times the thickness of each of the upper and lower layers), with a weight basis of about 4.1 ounces per square foot, and a density of about 3.3 pounds per cubic foot (approximately 55 percent of the density of each of the upper and lower layers). The resulting multi-layer insulating mat then has a combined thickness of about 1.25 inches, an average weight basis of about 6.6 ounces per square foot, and an average density of about 4 pounds per cubic foot.
EXAMPLE 3
[0034] For an insulating mat with a final thickness of about one and one-half inches, the first layer begins with a loose batt that is about 2.5 inches thick. The loose batt is subjected to needle punching with a puncture density of between about 500 PPSI and 600 PPSI to produce a relatively dense layer having a thickness of about 3/16 inch, a weight basis of about 1.5 ounces per square foot, and a density of about 6 pounds per cubic foot. In this embodiment, the first and second, or lower and upper, layers are formed in the same manner so that they have the same thickness, weight basis, and density, although they may be formed differently for a particular application.
[0035] Rolls of the first and second layers/mats are simultaneously fed to the needle loom as the lower and upper layers, while a loose batt of opened e-glass fibers are inserted between the two layers. This loose e-glass intermediate, or middle, layer has a thickness of about 5 inches as it is inserted between the lower and upper needled layers.
[0036] All three layers are subjected to a needling puncture density of 175 PPSI at a desired penetration as each of the first and second layers were previously penetrated. In effect, then, the lower and upper layers are each needle punched twice.
[0037] Following the needle punching of the three-layer construction, the upper and lower layers each have a thickness of approximately 0.19 inches, a weight basis of about 1.5 ounces per square foot, and a density of about 6 pounds per cubic foot. The intermediate layer is approximately 1.12 inches thick (approximately 5.9 times the thickness of each of the upper and lower layers), with a weight basis of about 5.0 ounces per square foot, and a density of about 3.3 pounds per cubic foot (approximately 55 percent of the density of each of the upper and lower layers). The resulting multi-layer insulating mat then has a combined thickness of about 1.5 inches, an average weight basis of about 8 ounces per square foot, and an average density of about 4 pounds per cubic foot.
EXAMPLE 4
[0038] For an insulating mat with a final thickness of about two inches, the first layer begins with a loose batt that is about 3 inches thick. The loose batt is subjected to needle punching with a puncture density of between about 500 PPSI and 600 PPSI to produce a mat having a thickness of about 0.24 inches, a weight basis of about 1.9 ounces per square foot, and a density of about 6.0 pounds per cubic foot. In this embodiment, the first and second, or lower and upper, layers are formed in the same manner so that they have the same thickness, weight basis, and density, although they may be formed differently for a particular application.
[0039] Rolls of the first and second layers/mats are simultaneously fed to the needle loom as the lower and upper layers, while a loose batt of opened e-glass fibers are inserted between the two layers. This loose e-glass intermediate, or middle, layer has a thickness of about 5.5 inches as it is inserted between the lower and upper needled layers.
[0040] All three layers are subjected to a needling puncture density of 175 PPSI at a desired penetration as each of the first and second layers were previously penetrated. In effect, then, the lower and upper layers are each needle punched twice.
[0041] Following the needle punching of the three-layer construction, the upper and lower layers each have a thickness of approximately 0.24 inches, a weight basis of about 1.9 ounces per square foot, and a density of about 6.0 pounds per cubic foot. The intermediate layer is approximately 1.52 inches thick (approximately 6.3 times the thickness of each of the upper and lower layers), with a weight basis of about 6.9 ounces per square foot, and a density of about 3.4 pounds per cubic foot (approximately 56 percent of the density of each of the upper and lower layers). The resulting multi-layer insulating mat then has a combined thickness of about 2 inches, an average weight basis of about 10.7 ounces per square foot, and an average density of about 4 pounds per cubic foot.
CONCLUSIONS
[0042] The inventors have found that a relatively thick, lightweight nonwoven insulating mat of fiberglass staple fibers can be produced by needle punching in thicknesses of about 1 inch and greater when the mat is formed as a multi-layer construction. Denser lower and upper layers are first needle punched, and a relatively looser intermediate layer is laid in between the lower and upper layers, all of which are simultaneously needle punched to obtain a stronger, smoother insulating mat. The resulting multi-layer insulating mat has a lower weight basis than could heretofore be produced with conventional processes.
[0043] Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be utilized without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims and their equivalents.
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A method is provided for forming a relatively thick, lightweight, nonwoven insulating mat. The method includes the steps of forming a relatively thin, relatively dense first outer layer by needle punching a first batt of glass fibers and forming a relatively thin, relatively dense second outer layer by needle punching a second batt of glass fibers. A relatively thicker, relatively less dense intermediate batt of glass fibers is fed between the first and second layers. Thereafter, the first layer, intermediate batt, and second layer are needle punched together to form a multi-layer mat having a first layer, middle layer, and second layer.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional application No. 60/044,982, filed on Apr. 28, 1997.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to waveguide grating routers, and, in particular, to waveguide grating routers that function as wavelength-dependent splitter/routers.
2. Description of the Related Art
An ideal optical splitter is a device that receives light of a particular wavelength at an input port and splits the power of that light evenly among a number of output ports. An ideal optical router is a device that routes light having different wavelengths from an input port to different output ports, where each output port corresponds to light having a different wavelength.
Optical devices that act as routers in one wavelength band and as splitters in another wavelength band have important applications in optical networks. This functionality is important for optical networks, because it enables the overlaying of a wavelength-division-multiplexed (WDM) network (which relies on routers) with a broadcast type of network (which relies on splitters).
Such devices are called two-PON-in-one devices or splitter/routers, where PON stands for passive optical network. When functioning as an optical splitter, a two-PON-in-one device splits light received at one input port among two or more output ports. When functioning as an optical router, a two-PON-in-one device receives light at one input port and routes light having different wavelengths to different output ports. Such a device may be referred to as a wavelength-dependent splitter/router, because the wavelength ranges of the light energy applied at the input port determine whether the device operates as either a splitter or as a router.
SUMMARY OF THE INVENTION
The present invention is directed to a wavelength-dependent optical splitter/router that is achieved by chirping a waveguide grating router (WGR). The chirped WGR of the present invention acts like an optical router in one wavelength band (referred to as "the routing band" or "the multiplexer band") and like an optical power splitter in another wavelength band (referred to as "the splitting band"). The invention has particular application in wavelength-division-multiplexed optical networks, access or trunk, where it is important to broadcast some signals to all receivers.
In one embodiment, the present invention is an optical device, comprising a waveguide grating router having a chirping function in which grating order is not constant over the router, wherein the router functions as an optical splitter in a first wavelength band and the router functions as an optical router in a second wavelength band.
BRIEF DESCRIPTION OF THE DRAWINGS
Other aspects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which:
FIG. 1 shows a schematic diagram of a conventional waveguide grating router;
FIGS. 2(A)-(C) show the response of a conventional waveguide grating router, such as the router of FIG. 1;
FIG. 3 shows a schematic diagram of a chirped waveguide grating router, according to one embodiment of the present invention;
FIG. 4 shows graphical representations of the chirping function for a chirped router and the corresponding simulated power distribution, according to one embodiment of the present invention;
FIGS. 5(A)-(C) show simulation results for a chirped router having the chirping function of FIG. 4; and
FIGS. 6(A)-(C) shows the results from an actual experimental chirped router having the chirping function of FIG. 4.
DETAILED DESCRIPTION
FIG. 1 shows a schematic diagram of a conventional (i.e., "unchirped") waveguide grating router 100 implemented as an integrated device formed on a suitable substrate 102 (e.g., silicon or silica). Router 100 has a plurality of input waveguides 106 adapted to receive light from one or more incoming optical fibers that can be connected to one or more of the input ports 104 of router 100. Router 100 also has a plurality of output waveguides 114 adapted to transmit light to one or more outgoing optical fibers that can be connected to one or more of the output ports 116 of router 100. Between the input and output waveguides are two free spaces 108 and 112 separated by a set of waveguides that form the grating arms 110 of the router.
In operation, light received at one of the input ports 104 is transmitted along the corresponding input waveguide 106 to free space 108. Light entering free space 108 is radiated for receipt by--and transmission along--each of the grating arms 110 towards free space 112. Light entering free space 112 is radiated towards the output waveguides 114.
Router 100 is preferably designed such that the difference in path length between going through two neighboring grating arms starting from a particular input port located at the input side of free space 108 to a particular output port on free space 112 is an integer multiple of the optical wavelength for which peak transmissivity is achieved for this pair of input-output ports. In a conventional router, such as router 100 of FIG. 1, there is a constant path-length difference ΔL between adjacent grating arms (taking into account the distances within free spaces 108 and 112, as well as the distances along the grating arms). As such, light of the selected wavelength entering free space 108 from the particular input waveguide 106 will be focused on the output side of free space 112 at the particular output waveguide 114. That is, light of the selected wavelength will constructively interfere (i.e., add in phase) at the particular output waveguide location, and substantially destructively interfere at all other output waveguide locations. Moreover, light of most other wavelengths will not, in general, be focused (i.e., will effectively destructively interfere) at the particular output waveguide location. As such, router 100 can be used as an optical passband filter. Light may constructively interfere at other locations on the output side of free space 112, but these so-called side-lobes can be effectively avoided if desired by failing to place output waveguides at those locations. Similarly, light of other particular wavelengths (i.e., related to the first wavelength by a periodic interval) may constructive interfere at the same particular output waveguide 106, but this too can be avoided by avoiding those particular wavelengths.
To the extent that router 100 can be designed to focus light having different wavelengths at different output waveguide locations on the output side of free space 112, router 100 can operate as a one-to-many optical demultiplexer that can receive light of different wavelengths from a single incoming optical fiber and selectively route those different wavelengths to different output ports for propagation along different outgoing optical fibers.
FIG. 2(A) shows the response of a conventional waveguide grating router, such as router 100 of FIG. 1, over the range of about 1520 nanometers (nm or 10 -9 meters) to about 1565 nm. FIGS. 2(B) and (C) show details of portions of FIG. 2(A). FIGS. 2(A)-(C) correspond to a conventional router being operated as a one-to-many optical demultiplexer. In that case, light of different wavelengths that is applied to a single input port is selectively routed to different output ports, with different output ports corresponding to different wavelength ranges. In FIG. 2(A), each transmission peak within the 1523-1532-nm range corresponds to light routed to a different output port. Similarly, each transmission peak within the 1553-1562-nm range corresponds to light routed to a different output port.
Similarly, router 100 can be further designed to operate as a many-to-one optical multiplexer that receives different wavelength light from different incoming optical fibers for transmission to a single outgoing optical fiber. Moreover, router 100 may be a symmetric optical device that can be operated in either direction (i.e., either from left to right or from right to left in FIG. 1). For example, FIG. 2(A) could also be interpreted to correspond to a situation in which a router is operated as a many-to-one optical multiplexer, where light of different wavelengths is applied to different ports on the right side of the router and routed to a single port on the left side of the router. Typically, a router is realized using silica waveguides deposited on a thick substrate of quartz or silicon.
The order q k of the k th grating arm in a router is defined by Equation (1) as follows:
q.sub.k =ΔL.sub.k n/λ.sub.p (1)
where ΔL k is the optical path-length difference between the k th grating arm and (k+1) th grating arm, n is the effective waveguide index, and λ p is the peak wavelength of the light energy for which the router is designed to operate. The effective waveguide index n is the refractive index taking into account the wavelength dispersion of the material. For glass, n is about 1.5. Since, in a conventional router, such as router 100 of FIG. 1, the path-length difference ΔL is the same for all pairs of adjacent grating arms, the grating order q is the same for each grating arm in the router. As such, in a conventional router, the grating order q is said to be constant. (Note that, since grating order relates to the path-length difference between adjacent grating arms, in a router having M grating arms, only the first M-1 grating arms are said to have a grating order.)
For example, a conventional router may be designed to operate with light having a peak wavelength λ p of 1540 nm, where the path-length difference ΔL between each pair of adjacent grating arms is selected to be 77 microns (μm or 10 -6 meters). Assuming an effective waveguide index n of 1.5, the grating order q for such a device would be (77 μm*1.5/1540 nm) or 75.
In a conventional router, transmission peaks will occur at periodic intervals that are related to the grating order of the router. In particular, a router of grating order q that has a transmission peak at λ p will have its next transmission peaks occurring at λ p ±λ p /q. The quantity λ p /q is usually referred to as the free spectral range (FSR) of the router.
FIG. 3 shows a schematic diagram of a chirped waveguide grating router 300, according to one embodiment of the present invention. A chirped router is one in which the path-length difference is not the same for all pairs of adjacent grating arms in the router. In general, in the context of waveguide grating routers, chirping refers to the process of designing a router such that the path-length difference is not constant over the entire device. According to the present invention, the grating arms and free spaces of chirped router 300 are specially designed such that chirped router 300 functions as an optical splitter in one wavelength band and as an optical router in another wavelength band. As such, chirped router 300 is a particular type of two-PON-in-one device or wavelength-dependent splitter/router.
Chirped router 300 is based on a double chirping technique in which the path length differences between the grating arms 310 as well as the angular placements of the waveguides (306 and 314) that feed into the free space couplers (308 and 312, respectively) are chirped. This assures that the total path length for each channel is taken into account. Double chirping somewhat complicates the design of the splitter/router, because the power distribution in the grating arms (310) is not only non-uniform, but also non-symmetric, as shown in the relative power curve of FIG. 4. The relative power curve in FIG. 4 shows simulation results for the chirping function that is also shown in FIG. 4.
Chirped router 300 is a 16-channel waveguide grating router, which uses a floating rib waveguide (i.e., where the rib is detached from the slab) in which the index step of the waveguide (i.e., the index difference between the waveguide core and the waveguide cladding) is set at 0.85% by setting the thickness of the rib to 80 nm. Inset 318 shows a waveguide cross-section for chirped router 300. This waveguide supports bends having a radius of curvature as tight as 620 μm. Chirped router 300 is laid out on a 90-degree angle, such that the facets of the input ports 304 and the output ports 316 are perpendicular to one another. The optical channel spacing (CS) is 100 GHz. The total device size measures 4.7×9 mm 2 . No cleaving techniques are used to reduce the device size.
In chirped router 300, the path-length difference between adjacent grating arms is not a constant, but rather depends on the arm number k. In that case, the grating order q k of the k th grating arm is given by q k =ΔL k n/λ p , where k=1, . . . M-1, where M is the number of grating arms in the router.
FIG. 4 shows a graphical representation of the chirping function of a chirped router, according to one embodiment of the present invention. The chirping function relates the grating arm number k to the grating order q k .
For example, as shown in FIG. 4, the 1 st grating arm in the chirped router (i.e., the grating arm corresponding to the shortest path length) has a grating order q 1 of 30. This means that the path-length difference between the 1 st and 2 nd grating arms is 30 times the peak wavelength λ p for which the router is designed. Similarly, the grating orders q 2 and q 3 for the 2 nd and 3 rd grating arms in the chirped router are also 30. However, the grating order q for each of the 4 th , 5 th , 6 th , and 7 th grating arms is 31, the grating order q for only the 8 th grating arm is 32, and so on, up to the 63 rd grating arm, which has a grating order q of 68.
Each set of one or more consecutive grating arms in a chirped router that have the same grating order may be said to be part of a sub-grating of the chirped router. Thus, grating arms 1-3 belong to a sub-grating having a grating order of 30, grating arms 4-7 belong to another sub-grating having a grating order of 31, grating arm 8 belongs to its own sub-grating having a grating order of 32, and so on, up to grating arm 63, which also belongs to its own sub-grating having a grating order of 68.
The chirped router of FIG. 4 has 39 different sub-gratings, where each sub-grating has one or more grating arms. The chirping function of the chirped router of FIG. 4 is such that the difference in grating order between adjacent sub-gratings (q k+1 -q k ) is 1. In general, the sub-gratings in the chirped router of FIG. 4 corresponding to central grating arms (i.e., grating arms 30-49) each have a single grating arm, while the sub-gratings corresponding to the outer grating arms (i.e., grating arms 1-29 and 50-63) tend to have two or more grating arms, where the outermost sub-gratings tend to have the most grating arms.
In the chirped router of FIG. 4, each sub-grating is designed to operate with a transmission peak at the same wavelength λ p . However, since each sub-grating has a different grating order q, the free spectral range (given by λ p /q) is different for each sub-grating and therefore the periodicity of the response of the chirped router is k-dependent. In general, each sub-grating with order q k has its next transmission peaks occurring at λ p ±λ p /q k . Thus, the next order peak wavelengths for the entire device are distributed over a "flat band" range FB given by FB=λ p {1/min(q k )-1/max(q k )}, which is the difference between the longest and shortest free spectral ranges of the different sub-gratings. Thus, for the chirped router of FIG. 4, assuming a peak transmission at λ p =1540 nm, the flat band range FB=1540 nm {1/30-1/68} or about 28-29 nm. In order to make this range as flat as possible, (q k+1 -q k ) between sub-gratings is set to 1 in the chirped router of FIG. 4, which makes the peaks of the sub-gratings very close to one another. This is not a necessary condition. For example, differences between subgratings of 2 might also work.
The preceding discussion applies to a single channel (i.e., the particular wavelength for which there is a peak in transmission). For multiple channels, the transmission peaks and flat bands are spectrally offset by the optical channel spacing (CS), where CS is the difference in wavelength between two neighboring channels. As such, the spectral width of the splitting band (SB) reduces to SB=FB-N×CS, where N is the number of channels. The loss difference (i.e., the difference in attenuation) between the splitting band and the routing band is approximately given by Δλ/FB, where Δλ is the filter bandwidth in the routing band. The filter bandwidth is defined as the full width at half maximum of the filter transmission characteristics. For a typical router, Δλ is approximately equal to CS/2. Since the flat band range FB needs to be at least N×CS in order for the splitting band to exist, the splitting loss is at least 1/(2N) or 3 dB more than the theoretical minimum of 1/N. Since any splitter always has a splitting loss of at least 1/N (N being the number of ports), a splitter/router of the present invention has at least twice that loss or 1/(2N). Thus, a trade-off between the number of channels (N), the spectral width of the splitting band (SB), and the optical channel spacing (CS) is made when the splitter/router is designed.
The chirping function is designed such that it produces optimal optical demultiplexing characteristics in the routing band and optimum splitting characteristics in the splitting band. This is best achieved by varying smoothly the order between the different sub-grating. The router band is defined by the wavelength range for which the path-length difference is an integer multiple of the optical wavelength. Splitter bands exist one free spectral range above and below the router band.
Chirped routers of the present invention were simulated taking into account the various effects from the double chirping. Several different chirping functions were analyzed in an attempt to flatten and broaden the spectral response in the splitting band. FIG. 4 shows the chirping function used for one of the simulated chirped routers. FIG. 4 also shows the relationship between grating arm number and relative power for that simulated chirped router. The outer arms (e.g., grating arm number less than 30 or more than 49), which carry less power than the central arms (e.g., grating arm number between 30 and 49), were arranged into groups (i.e., sub-gratings) of equal grating order to give them more weight. The group size was gradually decreased from 3 or 4 to 1 going toward the central waveguides. As shown in FIG. 4, both the chirping function and the power distribution are non-symmetric.
FIGS. 5(A)-(C) show simulation results for a chirped router having the chirping function of FIG. 4. FIG. 5(A) shows the transmissivity of the chirped router as a function of light wavelength from about 1520 nm to about 1565 nm. FIGS. 5(B) and B(C) are details from FIG. 5(A) corresponding to the routing band (about 1523-1532 nm) and the splitting band (about 1553-1565 nm), respectively, of the chirped router. According to the simulation, the light energy in the two bands is input at a single input port. Within each band, each curve shown in the figures represents the light energy corresponding to a different one of the eight output ports of the router.
As shown in FIGS. 5(A)-(C), there is a clean routing band with side-lobe levels well below 30 dB. Compared to an unchirped router, the side-lobe level, filter shape, and insertion loss (3 dB) of the routing band are not significantly altered by the chirping, although the filter response is slightly wider at the -25 dB level. The splitting band extends over almost 10 nm with a uniformity better than 1.5 dB. The insertion loss (i.e., the signal attenuation as it passes through the device) in this band is around 18 dB, 15 dB more than in the routing band or 9 dB above the intrinsic 1/N loss. Insertion loss is mainly caused by the losses in the two free space couplers due to the finite number of arms and the gap between the waveguides feeding into them. Doubling the number of ports to 16 would have reduced the splitting excess loss by 3 dB, but it would also have made the splitting band very narrow. There is a second splitting band (not shown) located symmetrically to the routing band on the blue wavelength side (i.e., to the left of the routing band in FIG. 5(A)). The two splitting bands correspond to the interference of order q k -1 for the red-shifted band and q k +1 for the blue-shifted band. There are even more splitting bands for the orders q k ±2,3,4, . . . However, the uniformity in these bands degrades as the difference between routing band order and splitting band order increases.
FIGS. 6(A)-(C) shows the results from an actual experimental chirped router having the chirping function of FIG. 4, according to one embodiment of the present invention. These experimental results clearly demonstrate the principle of the splitter/router, although they are not quite as good as the simulation results of FIGS. 5(A)-(C). The device was tested using a broadband light source (amplified spontaneous emission from an erbium-doped fiber amplifier) and an optical spectrum analyzer. The response shown in FIGS. 6(A)-(C) corresponds to measurements for TE polarization after being calibrated against a test waveguide. In the routing band, the insertion losses range from 3.5 dB (best channels) to 6.1 dB (worst channel). The spectrum in the routing band exhibits a side-lobe at about 15 dB down from the peak, which is attributed to multi-moding in the high index step waveguide structure. Multi-moding is when the waveguide supports several optical modes. With a more optimized waveguide, this side-lobe should disappear. General crosstalk levels are more than 25 dB down from the main peak. The apparent raise of crosstalk on the short wavelength side is an artifact of the measurement, because the spectral power of the source in this region was weak. Some of the insertion loss variations are due to differences in the waveguide-to-fiber coupling efficiency and are not inherent to the device. The chirped router is polarization sensitive and blue-shifts by 3.2 nm for TM polarization. The splitting band follows qualitatively the simulation. Insertion loss is around -21 dB and non-uniformity about 5 dB over a 6-nm range. Again, the non-uniformity is exaggerated by the high insertion loss of some channels. The spectral ripple on the individual curves is 1-2 dB in the 6-nm window.
Although the present invention has been described in the context of specific chirped routers, such as those represented by FIGS. 3 and 4, the present invention is not limited to those specific embodiments. In general, a chirping function according to the present invention is any chirping function that results in a chirped router that provides the desired wavelength-dependent splitting and routing functionality. Similarly, the overall configuration of the routers, including, for example, the lengths and numbers of grating arms and input and output waveguides, the sizes and shapes of the free spaces, and the angle formed by the grating arms, can also vary from device to device.
It will be further understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as expressed in the following claims.
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A wavelength-dependent splitter/router is made by chirping a waveguide grating router, such that the path-length difference between pairs of adjacent grating arms is not a constant. With careful design, a device can be fabricated that acts as an optical splitter in one wavelength band and as an optical router in another wavelength band. The invention has applicability in optical networks, because it enables the overlaying of a wavelength-division-multiplexed (WDM) network (which relies on routers) with a broadcast type of network (which relies on splitters).
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This is a divisional application of copending U.S. Ser. No. 160,805, filed Feb. 26, 1988, now U.S. Pat. No. 4,826,994, which in turn is a divisional application of copending U.S. Ser. No. 002,825, filed Jan. 13, 1987, now U.S. Pat. No. 4,775,690, issued Oct. 4, 1988, which in turn is a continuation-in-part application of copending U.S. Ser. No. 927,029, filed Nov. 5, 1986, now abandoned, which in turn is a divisional of copending U.S. Ser. No. 838,510, filed Mar. 11, 1986, now U.S. Pat. No. 4,670,462, issued Jun. 2, 1987.
BACKGROUND OF THE INVENTION
a. Field of Invention
This invention relates to novel indole derivatives, and to the processes for their preparation and use.
Notwithstanding the advances made during the last four decades in the development of agents for the treatment of pain-producing and inflammatory conditions, there still remains a need for effective agents without the side effects associated with the therapeutic agents presently used for this purpose.
More specifically, this invention relates to tricyclic acetic acid derivatives in which the tricyclic portion thereof is characterized by having an indole portion fused to a pyrano ring. Still more specifically, the compounds of this invention are characterized as derivatives of the following tricyclic acetic acid system: ##STR1## 1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid in which the carbons at the 1-, and 4-position, and optionally at the 5-, 6-, 7-, and 8-positions are further substituted.
The indole derivatives of this invention have been found to exhibit useful pharmacodynamic properties without eliciting undesirable side effects. Notable attributes of this effect are anti-inflammatory and analgesic activities.
b. Prior Art
The closest prior art to the present invention is:
Demerson et al, U.S. Pat. No. 3,939,178. Demerson et al disclosed 1,3,4,9-tetrahydropyrano[3,4-b]indoles and 1,3,4,9-tetrahydrothiopyrano[3,4-b]indoles having analgesic and anti-inflammatory activity but not with the substituents of the present invention. Related U.S. Pat. Nos. 3,974,179 and 3,843,681.
SUMMARY OF THE INVENTION
The compounds of this invention are represented by formula (I) ##STR2## wherein R 1 is lower alkyl containing 1 to 4 carbon atoms, R 2 and R 3 are hydrogen or R 2 and R 3 are joined together to give
--CH═CH--CH═CH--
and form a benzene ring, R 4 and R 5 are hydrogen, alkyl containing 1 to 6 carbon atoms, halogen, and the pharmaceutically acceptable salts thereof.
A preferred aspect of the present invention is the series of compounds represented by formula (II). ##STR3## wherein R 2 and R 3 are hydrogen or R 2 and R 3 are joined together to give
--CH═CH--CH═CH--
and form a benzene ring, R 4 and R 5 are hydrogen, lower alkyl containing 1 to 4 carbon atoms, halogen and the pharmaceutically acceptable salts thereof.
A still further preferred aspect of the present invention is the compounds represented by formula (II) wherein R 2 and R 3 are hydrogen or R 2 and R 3 are joined together to give
--CH═CH--CH═CH--
and form a benzene ring, R 4 is hydrogen, or 5-, 6-, or 7-halogen, R 5 is hydrogen, methyl, ethyl or propyl and the pharmaceutically acceptable salts thereof.
A further aspect of the present invention is the compounds represented by formula (XIV) ##STR4## wherein R 1 is lower alkyl containing 1 to 4 carbon atoms, R 4 and R 5 are hydrogen, alkyl containing 1 to 6 carbon atoms or halogen, and Y is 4-halogen, 2- and 4-dihalogen, 3-trifluoromethyl, or 4-methoxy and the pharmaceutically acceptable salts thereof.
The most preferred compounds of the present invention are designated
1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid;
7-chloro-1-ethyl-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)-pyrano[3,4-b]indole-1-acetic acid;
1-ethyl-7-fluoro-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)-pyrano[3,4-b]-indole-1-acetic acid;
8-chloro-1-ethyl-1,3,4,9-tetrahydro-5-methyl-4-(phenylmethyl)-pyrano[3,4-b]-indole-1-acetic acid;
1,8-diethyl-1,3,4,9-tetrahydro-4-(2-propenyl)-pyrano[3,4-b]indole-1-acetic acid;
1-ethyl-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)-pyrano[3,4-b]indole-1-acetic acid;
7-chloro-1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid;
6-bromo-1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid;
5-chloro-1-ethyl-1,3,4,9-tetrahydro-8-methyl-4-(phenylmethyl)-pyrano[3,4-b]-indole-1-acetic acid;
7,8-dichloro-1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid;
7-chloro-1-ethyl-1,3,4,9-tetrahydro-8-methyl-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid;
1-ethyl-1,3,4,9-tetrahydro-8-methyl-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid;
1-ethyl-1,3,4,9-tetrahydro-4-(2-propenyl)-8-propyl-pyrano[3,4-b]indole-1-acetic acid;
1,8-diethyl-1,3,4,9-tetrahydro-4-(2-propenyl)-pyrano[3,4-b]indole-1-acetic acid.
The indole derivatives of this invention of formula I are prepared by the following three processes. ##STR5##
Process A describes a process for preparing compounds of formula (I) and (II) which comprises the condensation of a substituted isatin (III), wherein R 4 and R 5 are as defined in formula (I) and (II), with the enolate of the carboxylic acid ester (IV), wherein R 2 and R 3 are as defined in formula (I) and (II), affording the hydroxyester intermediate (V) ##STR6##
The intermediate (V), without isolation, is reduced using a hydride, for example LiAlH 4 , to give the β-substituted tryptophol (VI), wherein R 2 , R 3 , R 4 and R 5 are as defined above. Reaction of the β-substituted tryptophol (VI) with 3-methoxy-2-alkanoic acid, methyl ester (VII), wherein R 1 is as defined in formula (I) and (II), in the presence of a Lewis acid, for example boron trifluoride etherate, followed by alkaline hydrolysis affords compounds of formula (I) and (II). Alternatively, condensation with a substituted β-keto ester, followed by hydrolysis, as described by Demerson et al, U.S. Pat. No. 3,939,178, affords compounds of formula (I) and (II).
Process A was used for the preparation of the compounds of Example 1 and 8-37, Table II. The required isatins III were prepared as described by Frank D. Popp, in Advances in Heterocyclic Chemistry, 18, pp 1-58 (1975).
Process B describes a process for preparing compounds of formula (I) and (II) which comprises alkylation of a substituted indole-3-acetic acid methyl ester VIII, wherein R 4 and R 5 are as defined in formula (I) and (II), with an organic halide (IX), wherein R 2 and R 3 are as defined in formula (I) and (II), to give the α-substituted indole-3-acetic acid ester (X), wherein R 2 , R 3 , R 4 and R 5 are as defined above. The ester (X) is reduced, for example with LiAlH 4 , to afford the β-substituted tryptophol (VI), described in Process A above. The compound (VI) is converted to the compound of formula (I) and (II) by Process A described above.
Process B was used for the preparation of the compound of Example 2, Table II.
Process C describes a process for preparing compounds of formula (I) and (II) which comprises the reaction of a substituted indole (XI), wherein R 4 and R 5 are as defined in formula (I) and (II), and a substituted acid chloride (XII), wherein R 2 and R 3 are as defined in formula (I) and (II), affording the substituted 3-acylindole (XIII), wherein R 2 , R 3 , R 4 and R 5 are as defined above. Rearrangement of compound (XIII) to the intermediate α-substituted indole-3-acetic acid ester (X), described in Process B is accomplished using thallium (III) nitrate by a method of E. C. Taylor et al, J. Amer. Chem. Soc. 98, 3037 (1976).
Process C was used for the preparation of the compounds of Example 4 and 5, Table II.
Process D describes a process for preparing compounds of formula (XIV) which comprises alkylation of a substituted indole-3-acetic acid methyl ester VIII, wherein R 4 and R 5 are as defined in formula (XIV), with a substituted benzyl halide (XV), wherein X is as defined in formula (XIV), to give the α-substituted indole-3-acetic acid ester (XVI), wherein R 4 , R 5 and X are as defined above. The ester (XVI) is reduced, for example with LiAlH 4 , to afford the β-substituted tryptophol (XVII). The compound (XVII) is converted to the compound of formula (XIV) by Process A described above.
Process D was used for the preparation of the compounds 40 to 45 of Table II.
Alternatively, the process described in U.S. Pat. No. 4,585,877, may be adapted for the production of the compounds of the present invention of formula (I) and (II).
DETAILED DESCRIPTION OF THE INVENTION
The term "alkyl" as used herein represents straight chain alkyl radicals containing from one to six carbon atoms and branched chain alkyl radicals containing from three to four carbon atoms and includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl and the like.
The term "lower alkyl" as used herein represents straight chain alkyl radicals containing 1 to 4 carbon atoms and branched chain alkyl radicals containing three to four carbon atoms and includes methyl, ethyl, propyl, isopropyl, butyl, isobutyl and the like.
The term "halogen" as used herein includes fluorine, chlorine, bromine and iodine.
The compounds of formula (I) form salts with suitable pharmaceutically acceptable inorganic and organic bases. These derived salts possess the same activities as the parent acid and are included within the scope of this invention. The acid of formula (I) is transformed in excellent yield into the corresponding pharmaceutically acceptable salts by neutralization of said acid with the appropriate inorganic or organic base. The salts are administered in the same manner as the parent acid compounds. Suitable inorganic bases to form these salts include, for example, the hydroxides, carbonates, bicarbonates or alkoxides of the alkali metals or alkaline earth metals, for example, sodium, potassium, magnesium, calcium and the like. The preferred salt is the sodium salt. Suitable organic bases include the following amines; lower mono-, di- and tri-alkylamines, the alkyl radicals of which contain up to three carbon atoms, such as methylamine, dimethylamine, trimethylamine, ethylamine, di- and triethylamine, methylethylamine, and the like; mono, di- and trialkanolamines, the alkanol radicals of which contain up to three carbon atoms, such as mono-, di-and triethanolamine; alkylenediamines which contain up to six carbon atoms, such as hexamethylenediamine; cyclic saturated or unsaturated bases containing up to six carbon atoms, such as pyrrolidine, piperidine, morpholine, piperazine and their N-alkyl and N-hydroxyalkyl derivatives, such as N-methylmorpholine and N-(2-hydroxyethyl)piperidine, as well as pyridine. Furthermore, there may be mentioned the corresponding quaternary salts, such as the tetraalkyl (for example tetramethyl), alkyl-alkanol (for example methyltrimethanol and trimethyl-monoethanol) and cyclic ammonium salts, for example the N-methylpyridinium, N-methyl-N-(2-hydroxyethyl)-morpholinium, N,N-dimethylmorpholinium, N-methyl-N-(2-hydroxyethyl)-morpholinium, N,N-dimethylpiperidinium salts, which are characterized by good water-solubility. In principle, however, there can be used all the ammonium salts which are physiologically compatible.
The transformations to the salts can be carried out by a variety of methods known in the art. For example, in the case of salts of inorganic bases, it is preferred to dissolve the acid of formula (I) in water containing at least one equivalent amount of a hydroxide, carbonate, or bicarbonate. Advantageously, the reaction is performed in a water-miscible organic solvent inert to the reaction conditions, for example, methanol, ethanol, dioxane, and the like in the presence of water. For example, such use of sodium hydroxide, sodium carbonate or sodium bicarbonate gives a solution of the sodium salt. Evaporation of the solution or addition of a water-miscible solvent of a more moderate polarity, for example, a lower alkanol, for instance, butanol, or a lower alkanone, for instance, ethyl methyl ketone, gives the solid salt if that form is desired.
To produce an amine salt, the acid of formula (I) is dissolved in a suitable solvent of either moderate or low polarity, for example, ethanol, acetone, ethyl acetate, diethyl ether and benzene. At least an equivalent amount of the amine corresponding to the desired cation is then added to that solution. If the resulting salt does not precipitate, it can usually be obtained in solid form by addition of a miscible diluent of low polarity, for example, benzene or petroleum ether, or by evaporation. If the amine is relatively volatile, any excess can easily be removed by evaporation. It is preferred to use substantially equivalent amounts of the less volatile amines.
Salts wherein the cation is quaternary ammonium are produced by mixing the acid of formula (I) with an equivalent amount of the corresponding quaternary ammonium hydroxide in water solution, followed by evaporation of the water.
Included in the present invention are the diastereoisomers wherein the 4-substituent is either cis or trans to the acetic acid chain at position one.
Also included in this invention are the optical isomers of the compounds of formula (I) which result from asymmetric centers, contained therein. Such isomers can be obtained in substantially pure form by classical separation techniques and by sterically controlled synthesis. Included is the specific case of the resolution of 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid into its optical isomers by separation of the corresponding [(1S)-endo]-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-yl ester followed by basic hydrolysis.
ANTI-INFLAMMATORY ACTIVITY
The useful anti-inflammatory activities of the pyranoindole acetic acid derivatives of formula (I) are demonstrated in standard pharmacologic tests, for example, the test designated: Preventative Adjuvant Edema
The objective of this test is to determine the ability of test drugs to exhibit an acute anti-inflammatory effect in rats. This test is a primary screen for anti-inflammatory drugs.
Species:
Male Sprague Dawley rats (180-200 g) are used. The animals have free access to water but food is withdrawn 18 hours before testing.
Drug Preparations and Administration:
Freund's complete adjuvant is prepared by suspending 5 mg of killed and dried Mycobacterium butyricum (Difco) in 1 mL mineral oil. The test compounds are dissolved, or suspended in 0.5% Tween 80 in distilled water according to their solubility. For primary screening all drugs are administered by gastric lavage at the arbitrary dosage of 25 mg/kg, p.o. in a volume of 0.5 mL/100 g body weight to groups of 10 animals.
Methodological Details:
The method is essentially that described by Wax et al, J. Pharmacol. Exp. Ther., 192, 166-171 (1975). Groups of rats are injected intradermally in the left hind paw with 0.1 mL of Freund's complete adjuvant. The test compound or vehicle is administered immediately before the adjuvant, 24 hours and 48 hours after the adjuvant (days 0, 1 and 2). The injected hind paw volume is measured before the injection of adjuvant and 24 hrs. after the last drug administration (day 3) by means of a plethysmometer (Buxco Electronics Inc.). The difference between the hind paw volume on day 0 and day 3 represents the edema volume. Etodolac (25 mg/kg, p.o.) is included as a positive control.
Presentation of Results:
The mean edema volume (expressed as mL±SEM) is calculated for each group and the percentage protection conferred by the drug is calculated: ##EQU1## where c is the mean edema volume for the vehicle-treated (0.5% Tween 80 in distilled water) controls and t is the mean edema volume for the drug treated group.
ANALGESIC ACTIVITY
A further test used to determine the utility of the compounds of the present invention is designated: Drug Effects on Phenylbenzoquinone-induced Writhing in Mice
The objective of this test is to determine the ability of test drugs to inhibit the nociceptive (pain) response of mice injected with a chemical irritant. This test is a primary screen for both peripheral and centrally acting analgesic drugs.
Species:
Male Swiss albino mice (15-25 g). The animals are fasted for 18 hours prior to use but have free access to water.
Drug Preparation and Administration:
Drugs are dissolved or suspended according to their solubility in 0.5% Tween 80 in distilled water. They are administered by gastric gavage in a volume of 5 mL/kg. For primary screening all drugs are administered at the arbitary dosage of 25 mg/kg, p.o. to a group of 10 mice.
Methodological Details:
A modification of the method of Siegmund et al, Proc. Soc. Exp. Biol. Med., 95, 729-731 (1957) is used. Groups of 5 mice are dosed with the test compound or vehicle control. Sixty minutes later the animals are injected i.p. with 0.3 mL/20 g body weight of a 0.02% solution of phenylbenzoquinone (PBQ; 2-phenyl-1,4-benzoquinone) and placed in individual observation boxes. The number of writhing or abdominal squirming movements made by each mouse during the following 15 min. period is counted. The experiment is repeated with another group of 5 mice and the mean number of writhes per mouse for a group of 10 mice is calculated.
Presentation of Results:
Drug treated and vehicle-treated control groups are compared and the percentage protection conferred by the drug is calculated: ##EQU2## where c=mean number of writhes in the control group where t=mean number of writhes in the test drug group
An additional test used to determine the utility of the compounds of the present invention is designated: Randall Selitto Test in the Rat
The objective of this test is to assess the potency of peripheral and central acting drugs in inhibiting the reaction of rats to painful stimulation applied to an inflamed paw.
Species:
Male Sprague Dawley rats (180-200 g) are used. The animals are fasted overnight prior to drug administration.
Drug Preparation and Administration:
Freund's Complete Adjuvant (FCA) is prepared by suspending 5 mg killed and dried mycobacterium butyricum (Difco) in 1 mL mineral oil. The test compounds are dissolved or suspended in 0.5% Tween 80 in distilled water according to their solubility. They are administered by gastric gavage in a volume of 0.5 mL/100 g body weight to groups of 10 animals.
Methodological details:
Ten rats are used per group. The method is essentially that described by Randall and Selitto, Arch. Int. Pharmacodyn. 111, 409 (1957) and the apparatus which is used to apply pressure to the paw (Analgesi-meter for the rat paw, Ugo Basile, Comeria, Italy) is a modification of that described by Gilfoil et al, J. Pharmacol. 142, 1 (1963). The instrument is basically a device which exerts a force that increases at a constant rate. The force is continuously monitored by a pointer moving along a linear scale and is measured in grams. The inflammatory reaction is induced in the left hind paw of rats by injecting 0.1 mL of Freund's adjuvant intradermally. The test compound or vehicle is administered 24 hours after the adjuvant. The pain threshold (vocalization) is determined 1 hour later in the inflamed paw of the treated and control groups.
Presentation of Results and Criteria for Activity:
Each animal which has a reading 1.5 times greater than the mean reading of the control-group will be considered as responsive (having an analgesic effect) to treatment. The number of animals showing an analgesic effect is then determined in each group.
The ED 50 (dose which causes analgesia in 50% of the animals) using at least 3 doses is then determined, by the method described in Litchfield and Wilcoxon, J. Pharmacol. Exp. Ther., 96, 99-113 (1949).
Typical results obtained for the compounds of the present invention in the aforementioned tests are as follows:
TABLE I______________________________________Substituted 1,3,4,9-Tetrahydropyrano[3,4-b]indole-1-acetic Acids Preventative Phenylquinone Randall SelittoExample Adjuvant Edema* Writhing in Mice* Test in the Rat*______________________________________ ##STR7##1 37 (1.9) (0.003)2 -- -- --3 -- 19 --4 15 86 (0.5)5 4 -- --6 (3.2) (18) --7 37 15 --10 (7.8) (7) 60.sup.b11 55 11 --12 .sup. 32.sup.a (9.5) (1)13 36 2 --14 46 21 --15 30 25 --16 (3) (5.5) (0.012)17 44 11 --18 15 (3.2) (0.8)19 52 (3.3) (1.6)20 34 11 --21 40 11 --22 47 (4.7) (0.25)23 0 (1.4) --24 2 0 --25 -- (3.1) --26 -- 10 --27 -- 24 --29 -- (3.2) --34 -- (1.4) -- ##STR8##40 60 47 --41 -- 30 --42 .sup. 18.sup.a .sup. 24.sup.a --43 .sup. 25.sup.a .sup. 47.sup.a --44 .sup. 25.sup.a .sup. 22.sup.a --45 .sup. 45.sup.a .sup. 29.sup.a --______________________________________ *The numbers quoted are either percent inhibition at 25 mg/kg or the ED.sub.50 in mg/kg given in parentheses. .sup.a Tested at 10 mg/kg. .sup.b Tested at 5 mg/kg.
The lack of side effects associated with the compounds of this invention are demonstrated by standard acute toxicity tests as described by R. A. Turner in "Screening Methods in Pharmacology," Academic Press, New York and London, 1965, pp. 152-163, and by prolonged administration of the compound to warm-blooded animals.
When the compounds of this invention are employed as anti-inflammatory and analgesic agents in warm-blooded animals, they are administered orally, alone or in dosage forms, i.e., capsules or tablets, combined with pharmacologically acceptable excipients, such as starch, milk sugar and so forth, or they are administered orally in the form of solutions in suitable vehicles such as vegetable oils or water. The compounds of this invention may be administered orally in sustained release dosage form or transdermally in ointments or patches. The compounds of this invention may also be administered in the form of suppositories.
The dosage of the compounds of formula I of this invention will vary with the particular compound chosen and form of administration. Furthermore, it will vary with the particular host under treatment. Generally, the compounds of this invention are administered at a concentration level that affords efficacy without any deleterious side effects. These effective anti-inflammatory and analgesic concentration levels are usually obtained within a therapeutic range of 1.0 μg to 500 mg/kg per day, with a preferred range of 1.0 μg to 100 mg/kg per day. The preferred anti-inflammatory dose range is 1 mg to 20 mg/kg b.i.d. The preferred analgesic dose range is 1 μg to 4 mg/kg b.i.d.
The compounds of this invention may be administered in conjunction with nonsteroid anti-inflammatory drugs such as acetaminophen, ibuprofen and aspirin and/or with opiate analgesics such as codeine, oxycodone and morphine together with the usual doses of caffeine. When used in combination with other drugs, the dosage of the compounds of the present invention is adjusted accordingly.
The compounds of the present invention also possess antipyretic activity.
The following examples further illustrate this invention.
EXAMPLE 1
1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid (Isomer A)
(I, R 1 =--C 2 H 5 , R 2 and R 3 =--CH═CH--CH═CH--, R 4 and R 5 =--H)
Step 1. Preparation of 3-Phenylpropionic Acid, Methyl Ester
A mixture of 3-phenylpropionic acid (118.2 g, 788 mmol) sulfuric acid (5.9 g), and 100 mL of methanol was heated to reflux overnight. TLC analysis indicated the absence of starting material and the reaction was concentrated in vacuo. The residue was dissolved in 200 mL of ethyl ether, washed with sodium bicarbonate (100 mL), dried over magnesium sulfate, filtered and concentrated to give 124.4 g (96.3%) of the ester as a tan oil.
IR (neat) 3020, 2940, 1730 cm -1 .
Step 2. Preparation of β-(Phenylmethyl)-1H-indole-ethanol
To a solution of lithium diisopropylamine in tetrahydrofuran/cyclohexane (2.2 M, 136.4 mL, 300 mmol), cooled to -78° C. under a nitrogen atmosphere, was added a solution of 3-phenylpropionic acid, methyl ester (44.6 g, 272 mmol) (prepared in Step 1) in 150 mL of dry tetrahydrofuran. The mixture was allowed to stir for 30 minutes. A solution of isatin (20.0 g, 136 mmol) in 300 mL of tetrahydrofuran was added dropwise and the mixture was allowed to warm to room temperature for 3 hours. The mixture was quenched with 500 mL of saturated ammonium chloride and the layers were separated; the aqueous layer was washed with ether (2×150 mL). The combined organic extracts were dried over magnesium sulfate, filtered and concentrated to give 71.8 g of a brown oil. 3-Phenylpropionic acid, methyl ester was removed by distillation (95° C./1.5 mm) and the residue (50.6 g) was dissolved in 300 mL of dry tetrahydrofuran and added slowly to a cooled (0° C.) mixture of lithium aluminum hydride (18.56 g, 489 mmol) in 225 mL of tetrahydrofuran. The mixture was allowed to warm to room temperature and was then heated under reflux for 3 hours. The mixture was then cooled in an ice water bath, and 250 mL of water was slowly added. The salts were collected by filtration and washed with ether (3×400 mL). The organic layer was separated from the filtrate and dried over magnesium sulfate, filtered and concentrated to give 35.5 g of a red-brown oil. This material was purified by flash chromatography (30% ethyl acetate/hexane, silica gel) to give the tryptophol as a brown oil (16.02 g, 46.9%).
1 H NMR(CDCl 3 ) δ8.08 (s, 1H), 7.65 (d, 1H, J=7.5 Hz), 7.36 (d, 1H, J=7.5 Hz), 7.18 (m, 7H), 7.01 (d, 1H, J=2.0 Hz), 3.84 (d, 2H, J=5.0 Hz), 3.43 (dt, 1H, J=7.5 Hz), 3.10 (d, 2H, J=8.0 Hz), 1.79 (s, 1H).
IR (neat) 3420, 3020 cm -1 .
Step 3. Preparation of 1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid, Methyl Ester
A solution of β-(phenylmethyl)-1H-indole-ethanol (15.97 g, 63.6 mmol) (prepared in Step 2), methyl propionyl acetate (9.95 g, 76 mmol), and p-toluenesulfonic acid (1.60 g) in 500 mL of benzene was heated under reflux for 3 hours, and water collected with a Dean & Stark receiver. The reaction mixture was cooled to room temperature and washed with 5% aqueous sodium bicarbonate (200 mL), water (200 mL), dried over magnesium sulfate, filtered and concentrated to give 21.37 g of the crude product. The diastereomers were separated by flash chromatography (13% ethyl acetate/hexane, silica gel) to give Isomer A (higher Rf, 2.26 g, 9.8%) and Isomer B (lower Rf, 2.23 g, 9.8%) as yellow oils.
ISOMER A
1 H NMR(CDCl 3 ) δ9.17 (s, 1H), 7.42-7.00 (m, 9H), 3.80 (m, 2H), 3.72 (s, 3H), 3.20 (m, 2H), 3.01 (d, 1H, J=17 Hz), 2.80 (d, 1H, J=17 Hz), 2.85 (m, 1H), 2.05 (q, 2H, J=7.5 Hz), 0.90 (t, 3H, J=7.5 Hz).
IR (KBr) 3420, 1725 cm -1 .
ISOMER B
1 H NMR(CDCl 3 ) δ8.88 (s, 1H), 7.38-7.00 (m, 9H), 3.84 (m, 2H), 3.70 (s, 3H), 3.04 (d, 1H, J=17.5 Hz), 2.78 (d, 1H, J=17.5 Hz), 3.15 (m, 2H), 2.82 (m, 1H), 2.20 (q, 2H, J=7.5 Hz), 0.82 (t, 3H, J=7.5 Hz).
IR (KBr) 3440, 1725 cm -1 .
Step 4. Preparation of 1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid
1-Ethyl-4-(phenylmethyl)-1,3,4,9-tetrahydropyrano(3,4-b)indole-1-acetic acid, methyl ester Isomer A (prepared in Step 3) (3.0 g, 8.25 mmol) was dissolved in 100 mL of ethanol, and 100 mL of 10% aqueous sodium hydroxide was added. The mixture was heated under reflux for 2 hours, and was then concentrated to a cloudy aqueous solution. Concentrated hydrochloric acid was added until the mixture was acidic. It was then washed with ether (2×100 mL) and the combined ether extracts were dried over magnesium sulfate, filtered and concentrated to give 2.8 g of an off-white foam. This material was recrystallized from benzene/petroleum ether to give 2.30 g (80%) of the pure acid as a white solid, m.p. 144°-146° C.
1 H NMR(CDCl 3 ) δ8.70 (s, 1H), 7.43-7.03 (m, 9H), 3.87 (d, 2H, J=2.5 Hz), 3.23 (m, 2H), 2.97 (d, 2H, J=3.0 Hz), 2.85 (m, 1H), 2.04 (m, 2H), 0.93 (t, 3H, J=7.5 Hz).
IR (KBr) 3380, 3260, 1740 cm -1 .
Anal. Calcd. for C 22 H 23 NO 3 : C, 75.62; H, 6.63; N, 4.01 Found: C, 75.96; H, 6.43; N, 3.99.
Preparation of 1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid, Sodium Salt (Isomer A)
Aqueous NaOH (2.6 mL of 1N solution) was added to a stirred solution of 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid (0.965 g, 2.76 mmol) in methanol (50 mL). The pH was adjusted to 7.75 by the portionwise addition of 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid. The resulting solution was evaporated to dryness and then taken into benzene and evaporated (2 x). The residue was dissolved in ethyl acetate (8 mL), stirred, and petroleum ether (30°-60°, 30 mL) was added slowly. The precipitate which formed was stirred for 1 hour, filtered, washed with petroleum ether, and dried to afford 1.0 g (98%) of the salt as a white solid, m.p. 180°-190° C. (dec.).
______________________________________NMR(DMSO-d.sub.6):No. of protons Type Chemical Shift (δ)______________________________________3 CH.sub.3 0.84 (t, J = 8)2 CH.sub.2 2.0 (2q, J = 8)7 3CH.sub.2,CH 2.2-3.9 (m)9 aromatic 6.9-7.2 (m)______________________________________
Anal. Calcd.: C, 71.14; H, 5.97; N, 3.77% Found: C, 70.41; H, 6.03; N, 3.64%.
EXAMPLE 2
1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid, Methyl Ester (Isomer A)
Step 1. Preparation of Indole-3-acetic Acid, Methyl Ester
Indole-3-acetic acid (25 g, 143 mmol) was dissolved in 500 mL of methanol and 5 mL of concentrated sulfuric acid was added. The resulting solution was heated under reflux overnight. TLC analysis indicated the absence of starting material and the reaction mixture was concentrated in vacuo. The residue was dissolved in 300 mL of ethyl ether, washed with 5% aqueous sodium bicarbonate (2×150 mL), dried over magnesium sulfate, filtered and concentrated to 24.09 g (89.1%) of the ester as a burgandy colored oil.
IR (neat) 3400, 1720 cm -1 .
NMR(CDCl 3 ) δ8.17 (s, 1H), 7.62 (d, 1H, J=6.7 Hz), 7.32-7.07 (m, 4H), 3.79 (s, 3H), 3.70 (s, 3H).
Step 2. Preparation of α-(Phenylmethyl)-1H-indole-3-acetic Acid, Methyl Ester
To a 2-liter three necked round bottom flask equipped with an addition funnel was added, under nitrogen, 300 mL of dry tetrahydrofuran (THF) and 68.75 mL of lithium diisopropylamide (1.92 M in cyclohexane/THF, 132 mmol). The mixture was cooled to -78° C., and a solution of indole-3-acetic acid, methyl ester (11.36 g, 60 mmol) in 300 mL of dry tetrahydrofuran was added dropwise. The mixture was then allowed to sit at -78° C. for 15 minutes, and then a solution of benzyl chloride (7.59 g, 60 mmol) in 300 mL of tetrahydrofuran was added dropwise. The reaction mixture must be stirred vigorously so that the precipitated dianion of indole-3-acetic acid, methyl ester reacts completely with the benzyl chloride. After 3 hours, TLC analysis indicated complete consumption of starting material, and 200 mL of aqueous saturated ammonium chloride was added. The aqueous layer was separated and washed with ether (2×100 mL). The combined ether extracts were added to the organic layer which was dried over magnesium sulfate, filtered and concentrated to 15.0 g (quantitative yield) of red-brown oil. This material was reduced to the corresponding tryptophol without further purification.
1 H NMR(CDCl 3 ) δ8.09 (s, 1H), 7.73 (d, 1H, J=7 Hz), 7.40-7.09 (m, 9H), 4.19 (dd, 1H), 3.59 (s, 3H), 3.47 (dd, 1H), 3.20 (dd, 1H).
IR (neat) 3400, 1730 cm -1 .
Step 3. Preparation of β-(Phenylmethyl)-1H-indole-ethanol
The crude α-(phenylmethyl)-1H-indole-3-acetic acid, methyl ester obtained in Step 2 (15 g, 60 mmol) was dissolved in 100 mL of dry tetrahydrofuran and added dropwise to a cooled suspension of lithium aluminum hydride (2.73 g, 72 mmol) in 300 mL of tetrahydrofuran. The mixture was allowed to warm to room temperature and was then refluxed for 1.5 hours (heating is usually not required in this reaction). The mixture was cooled in an ice water bath and 150 mL of 1N hydrochloric acid was added dropwise. The aqueous layer was removed and the organic layer was washed with saturated sodium bicarbonate (2×100 mL), dried over magnesium sulfate, filtered and evaporated to produce 15.06 g (quantitative yield) of a brown oil having the same physical properties as the product obtained in Example 1, Step 2. This material was cyclized to the pyranoindole in Step 4 without further purification.
Step 4. Preparation of 1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)pyrano[3,4-b]indole-1-acetic Acid, Methyl Ester
The crude β-(phenylmethyl)-1H-indole-ethanol obtained in Step 3 (15.06 g, 60 mmol) was dissolved in 250 mL of methylene chloride. 3-Methoxy-2-pentenoic acid, methyl ester (10.68 g, 72 mmol) was added followed by 2.5 mL of boron trifluoride etherate and the mixture was allowed to stir at room temperature overnight. TLC analysis indicated that the reaction was complete and 200 mL of saturated sodium bicarbonate was added. The organic layer was separated and washed with water (2×100 mL), dried over magnesium sulfate, filtered and concentrated to give a crude product which was purified by flash chromatography (13% ethyl acetate/hexane, silica gel). 2.5 g (11.5% based on 3 steps) of almost pure Isomer A was obtained. The proton NMR of this compound matched that of the sample prepared by the procedure described in Example 1, Step 3.
EXAMPLE 3
1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid (Isomer B)
(I, R 1 =--C 2 H 5 , R 2 and R 3 =--CH═CH--CH═CH--, R 4 and R 5 =--H)
The 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]-indole-acetic acid, methyl ester Isomer B, (prepared in Example 1, Step 3) (2.19 g, 6.0 mmol) was added to a mixture of 65 mL of 10% aqueous sodium hydroxide and 65 mL of ethanol and the reaction mixture was heated under reflux for 2 hours. The mixture was then concentrated to dryness and a 1:1 mixture of 10% sodium hydroxide/ether was added to the residue. The aqueous layer was separated, acidified with concentrated hydrochloric acid, and extracted several times with ether. The combined ether extracts were dried over magnesium sulfate, filtered and concentrated to give 1.68 g (80%) of a tan-yellow solid. This material was purified by flash chromatography (30% ethyl acetate/hexane, silica gel) to give 410 mg of material which was recrystallized from benzene/petroleum ether to give 315 mg (15%) of the acid as a white solid, m.p. 171°-173° C.
1 H NMR(CDCl 3 ) δ8.48 (s, 1H), 7.39-7.01 (m, 9H), 3.90 (dd, 2H, J=7.5 Hz, J=2.5 Hz), 3.19 (m, 2H), 3.02 (d, 2H, J=3 Hz), 2.88 (m, 1H), 2.15 (m, 2H), 0.89 (t, 3H, J=7.5 Hz).
IR (KBr) 3390, 1722 cm -1 .
Anal. Calcd. for C 22 H 23 NO 3 : C, 75.62; H, 6.63; N, 4.01 Found: C, 75.76; H, 6.35; N, 3.95.
EXAMPLE 4
1,8-Diethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid
(I, R 1 =--C 2 H 5 , R 2 and R 3 =--CH═CH--CH═CH--, R 4 =--H, R 5 =8--C 2 H 5 )
Step 1. Preparation of 1-(7-Ethyl-1H-indol-3-yl)-3-phenylpropanone
To a vigorously stirred solution of ethyl magnesium bromide (2.85 M in ether, 0.07 mol, 24.6 mL) in anhydrous ether (50 mL), was added a solution of 7-ethyl-1H-indole (7.25 g, 0.05 mol) in benzene (25 mL), dropwise over the course of 10 minutes. The resulting pale green mixture was heated at reflux for 2 hours, and then cooled to -10° C. with a dry ice/methanol bath. A solution of hydrocinnamoyl chloride (8.43 g, 0.05 mol) in benzene (20 mL) was added dropwise (45 minutes). The reaction mixture was allowed to warm to room temperature; after an additional 2 hours, no starting material was detected by TLC analysis. Aqueous ammonium chloride (10%, 30 mL) was added to the reaction mixture and a white precipitate formed, which was collected by filtration, washed with ether, and dried in vacuo to yield 7.78 g (56%) of the desired ketone, m.p. 140°-141.5° C.
IR(CHCl 3 ) 3465, 1645 cm -1 .
NMR(CDCl 3 ) δ9.39 (s, 1H), 8.30 (d, 1H), 7.80 (d, 1H) 3.12 (s, 4H), 2.88 (q, 2H), 1.32 (t, 3H).
Step 2. Preparation of 7-Ethyl-α-(phenylmethyl)-1H-indole-3-acetic Acid Methyl Ester
According to the procedure of E. C. Taylor et al, J. Amer. Chem. Soc., 98, 3037 (1976), a solution of 1-(7-ethyl-1H-indol-3-yl)-3-phenylpropanone (2.77 g, 10 mmol) in a 1:1 mixture of methanol and trimethylorthoformate (25 mL) was added to thallium (III) nitrate trihydrate (4.88 g, 11 mmol), and the mixture was heated under reflux until precipitation of thallium (I) nitrate was complete (about 3 hours). The dark brown mixture was diluted with 25 mL of ether, and the thallium (I) nitrate was removed by filtration. The filtrate was washed successively with 1×50 mL portions of water, 5% aqueous sodium bicarbonate, and water and was then dried over anhydrous MgSO 4 . Concentration of the filtrate and flash chromatography of the crude product (20% ethyl acetate/hexane, silica gel) gave the ester as a red-brown oil (0.98 g, 31.9%).
IR(CHCl 3 ) 3485, 1735 cm -1 .
NMR(CDCl 3 ) δ8.35 (s, 1H), 7.70 (dd, 1H), 7.15 (m, 3H), 4.28 (m, 1H), 3.75 (s, 3H), 3.35 (s, 3H), 2.80 (q, 2H), 1.25 (m, 3H).
Step 3. Preparation of 7-Ethyl-β-(phenylmethyl)-1H-indole-ethanol
To a stirred suspension of lithium aluminum hydride (0.702 g, 18.5 mmol) in 80 mL of anhydrous tetrahydrofuran under nitrogen at 0° C. was slowly added (about 1.5 hours) a solution of 7-ethyl- α-(phenylmethyl)-1H-indole-3-acetic acid methyl ester (prepared in Step 2) (5.17 g, 16.8 mmol) in 30 mL of anhydrous tetrahydrofuran. The resulting dark red mixture was heated under reflux for 2 hours. It was cooled to 0° C., and quenched by the dropwise addition of 40 mL of water. The precipitated aluminum salts were removed by filtration and washed with ether. The layers of the filtrate were separated, and the aqueous layer was washed with ether. The combined ether layers were washed with saturated sodium chloride, dried over anhydrous magnesium sulfate, and concentrated to give the desired alcohol as a brown oil (4.51 g, 96%).
IR(CHCl 3 ) 3570, 3480 cm -1 .
NMR(CDCl 3 ) δ6.8-8.40 (m, 10H), 3.0-4.10 (m, 5H), 2.80 (q, 2H), 1.32 (t, 3H).
Step 4. Preparation of 1,8-Diethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)pyrano[3,4-b]indole-1-acetic Acid (Isomer A)
7-Ethyl- β-(phenylmethyl)-1H-indole-ethanol prepared in Step 3) (5.86 g, 21.0 mmol), methyl propionyl acetate (4.69 g, 36.0 mmol) and p-toluenesulfonic acid (0.49 g, 2.6 mmol) were dissolved in 175 mL of benzene and heated under reflux for 5 hours, and water collected with a Dean & Stark receiver. The mixture was washed with saturated sodium bicarbonate (2×50 mL), dried (MgSO 4 ), filtered and evaporated to give the crude methyl ester. This material was dissolved in a mixture of 125 mL of ethanol and 125 mL of 10% aqueous sodium hydroxide, and the mixture of heated under reflux for 21/2 hours. It was then concentrated to dryness, and a mixture of 100 mL of ether and 50 mL of 10% aqueous sodium hydroxide was added to the residue. The layers were separated, and the aqueous layer was acidified with concentrated hydrochloric acid and extracted with ether (2×100 mL). The combined ether extracts were dried over anhydrous MgSO 4 , filtered and evaporated to give the crude product as a tan solid (44% yield). The diastereomers were partially separated by flash chromatography (30% ethyl acetate/hexane, H 3 PO 4 treated silica gel), and a portion of the mixed fractions from the column were separated by HPLC (Waters Assoc. C18, Prep 500). The isomer which eluted first on the C18 column was designated Isomer A and had a m.p. 147°-148.5° C.; the other isomer was designated Isomer B and had a m.p. 158°-159.5° C. Each isomer was recrystallized from 1:3 benzene/petroleum ether.
ISOMER A
IR(KBr) 3600-2600, 3330, 1740 cm -1 . Analytical HPLC: 97.98% isomeric purity.
Anal. Calcd. for C 24 H 27 NO 3 : C, 76.35; H, 7.22; N, 3.71 Found: C, 76.28; H, 7.25; N, 3.81.
EXAMPLE 5
1,8-Diethyl-1,3,4,9-tetrahydro-4-(phenylmethyl-pyrano[3,4-b]indole-1-acetic Acid (Isomer B)
ISOMER B
Prepared in Example 4, Step 4.
IR(KBr) 3600-2600, 3460, 1700 cm -1 . Analytical HPLC: 96.90% isomeric purity.
Anal. Calcd. for C 24 H 27 NO 3 : C, 76.35; H, 7.22; N, 3.71 Found: C, 76.28; H, 7.25; N, 3.81.
EXAMPLE 6
1-Ethyl-7-fluoro-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)pyrano[3,4-b]indole-1-acetic Acid (Isomer A)
(I, R 1 =--C 2 H 5 , R 2 and R 3 =--H, R 4 =7-F, R 5 =8-CH 3 )
Step 1. Preparation of 6-Fluoro-7-methylisatin
A mixture consisting of 3-fluoro-2-methyl aniline hydrochloride (21.9 g), water (500 mL), hydroxylamine hydrochloride (29 g), sodium sulfate (120 g) and a few drops of 6N HCl was heated to boiling with vigorous stirring. To this was added a boiling solution of chloral hydrate (21.9 g in 330 mL of water) and boiling continued for 45 minutes.
The reaction was cooled and filtered. The precipitate was dissolved in ether, dried over sodium sulfate and evaporated to afford 18.7 g of the oxime (88% yield).
The oxime was added portionwise to 300 mL of 90% sulfuric acid at 65° C. The mixture was heated to 80° C. for 15 minutes and then poured over ice water while stirring. Filtration and drying afforded 11.7 g (60% yield) of 6-fluoro-7-methylisatin, m.p. 204°-206° C.
Step 2. Preparation of 6-Fluoro-7-methylindole-3-(2-allyl)ethanol
A solution of lithium diisopropylamine (LDA) (2.2 M in cyclohexane, 110 mL) was cooled to -78° C. in an isopropylamine (IPA) dry ice bath. Methyl 4-pentenoate (24.0 g, 0.206 mol) in dry tetrahydrofuran (100 mL) was introduced, and the reaction stirred for 0.5 hours. A solution of 6-fluoro-7-methylisatin (prepared in Step 1) (19 g, 0.106 mol) in tetrahydrofuran (150 mL) containing 2-methylpyrrolidone (22 mmol) was added slowly while keeping the temperature of the reaction below -60° C. The reaction was stirred at -78° C. for 2 hours and then allowed to reach room temperature. The excess LDA was quenched using saturated ammonium chloride solution. The organic layer was extracted with ether (2×200 mL), dried (Na 2 SO 4 ) and concentrated to afford 40.0 g of crude intermediate hydroxyester.
A solution of this hydroxyester intermediate in tetrahydrofuran (500 mL) was added dropwise to a stirred suspension of LiAlH 4 (9.8 g, 0.258 mol) in tetrahydrofuran (200 mL), and refluxed for 2 hours. The reaction was cooled in an ice bath, the excess hydride destroyed using 1:1 tetrahydrofuran/H 2 O, filtered, dried (Na 2 SO 4 ) and concentrated to give 30 g of crude tryptophol. Flash chromatography using 25% ethyl acetate/hexane followed by 30% ethyl acetate/hexane afforded 11.7 g (48% yield) of title compound. This material was immediately used in Step 3.
Step 3. Preparation of 1-Ethyl-7-fluoro-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)-pyrano[3,4-b]indole-1-acetic Acid (Isomer A)
A mixture consisting of 6-fluoro-7-methylindole-3-(2-allyl)ethanol (prepared in Step 2) (11.0 g, 0.048 mol), 3-methoxy-2-pentenoic acid, methyl ester (11 g), BF 3 ·Et 2 O (1 mL) and dichloromethane (500 mL) was stirred at room temperature for 2 hours, diluted with dichloromethane, washed with 5% NaHCO 3 , water, dried (MgSO 4 ) and concentrated to give 21 g of oil. This was washed through a silica gel column using hexane followed by 5% ethyl acetate-hexane. Preparative liquid chromatography on a Waters Assoc. Prep 500 instrument using 3.5% ethyl acetate-hexane as eluant afforded the esters (5 g of Isomer A and 6.5 g of Isomer B).
Isomer A ester was hydrolyzed by refluxing with a mixture of KOH (5 g), methanol (500 mL), and water (10 mL) for 2.5 hours. The reaction was concentrated, diluted with water, and extracted with ether. The aqueous phase was acidified with 5% HCl and extracted with chloroform (3×200 mL). The combined extracts were washed with water, dried (MgSO 4 ) and concentrated to give 3 g of solid acid. Recrystallization from toluene-petroleum ether afforded 2.0 g (12.6% yield) of title compound, m.p. 159°-160° C.
______________________________________NMR(DMSO-d.sub.6):No. of Protons Type Chemical Shift (δ)______________________________________3 CH.sub.3 0.72 (t, J = 7)2 CH.sub.2 1.95 (m)3 CH.sub.3 2.35 (s)2 ═CH.sub.2 5.1 (m)1 H--C═C 5.8 (m)2 aromatic 10.6, 11.9 (s)______________________________________
IR (KBr, cm -1 ) 3070 (NH/OH), 1710 (CO).
Anal. Calcd: C, 68.87; H, 6.69; N, 4.23% Found: C, 68.94; H, 6.61; N, 4.15%.
EXAMPLE 7
1-Ethyl-7-fluoro-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)pyrano[3,4-b]indole-1-acetic Acid (Isomer B)
1-Ethyl-7-fluoro-1,3,4,9-tetrahydro-8-methyl-4-(2-propenyl)pyrano[3,4-b]indole-1-acetic acid Isomer B ester, prepared in Example 6, Step 3, was hydrolyzed as described in Example 6, Step 3, to afford 2.1 g of white solid. Recrystallization from toluene-petroleum ether afforded 1.3 g (8.1% yield) of title compound, m.p. 133°-140° C.
______________________________________NMR(DMSO-d.sub.6):No. of Protons Type Chemical Shift (δ)______________________________________3 CH.sub.3 0.62 (t, J = 7)1 CH.sub.3 2.35 (s)2 CH.sub.2 2.06 (m)2 ═CH.sub.2 5.1 (m)1 H--C═C 5.8 (m)2 aromatic 10.6, 11.9 (s)______________________________________
IR (KBr, cm -1 ) 3070 (NH/OH), 1710 (CO).
Anal. Calcd.: C, 68.87; H, 6.69; N, 4.23% Found: C, 68.98; H, 6.77; N, 4.18%.
EXAMPLE 8
Resolution of (+/-)-1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid
Step 1. Preparation of 1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)pyrano[3,4-b]indole-1-acetic Acid, [(1S)-Endo]-1,7,7-Trimethyl-bicyclo[2.2.1]heptan-2-yl Ester
50 mL of methylene chloride was added to a mixture of 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid (3.50 g, 10 mmol), [(1S)-endo]-(-)-borneol (1.70 g, 11 mmol), 1,3-dicyclohexylcarbodiimide (2.27 g, 11 mmol) and 4-(N,N-dimethylamino)pyridine (70 mg, 0.57 mmol). The mixture was allowed to stir at room temperature overnight under a stream of nitrogen. The mixture was passed through a sintered glass funnel and the precipitate was washed with 50 mL of methylene chloride. The filtrate was poured into 100 mL of ether and was washed with 1N hydrochloric acid (2×50 mL) and saturated sodium bicarbonate (1×50 mL), dried over magnesium sulfate, filtered and concentrated to give 3.85 g of the crude mixture of esters. Flash chromatography (10% ethyl acetate/hexane, silica gel) gave 2.65 g of the diastereomeric mixture of esters as a white foam. The esters were separated by HPLC (Waters Prep. 500A, 4 % ethyl acetate/hexane, silica gel) to give 1.2 g of Isomer A (first eluting isomer) m.p. 63°-66° C., and 1.15 g of Isomer B (second eluting isomer) m.p. 58°-61° C.
Step 2. Preparation of (+)-1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)pyrano[3,4-b]indole-1-acetic Acid
The 1-ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid, [(1S)-endo]-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-yl ester (Isomer A, 1.20 g, 2.5 mmol) was dissolved in a mixture of 65 mL of ethanol and 65 mL of 10% sodium hydroxide, and the mixture was heated under reflux for 5 hours. The mixture was then concentrated to a cloudy aqueous solution, cooled in an ice water bath, and acidified with concentrated hydrochloric acid. It was then extracted with ether (2×50 mL) and the combined ether extracts were dried over magnesium sulfate, filtred and concentrated to give 900 mg of a yellow oil. This material was recrystallized from toluene to give 397 mg (46%) of the pure acid as a white solid, m.p. 170°-171.5° C.
Anal. Calcd. for C 22 H 23 NO 3 : C, 75.62; H, 6.63; N, 4.01 Found: C, 75.63; H, 6.44; N, 4.17.
[α] D 25 =+62.9°.
EXAMPLE 9
Preparation of (-)-1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic Acid
1-Ethyl-1,3,4,9-tetrahydro-4-(phenylmethyl)-pyrano[3,4-b]indole-1-acetic acid, [(1S)-endo]-1,7,7-trimethyl-bicyclo[2.2.1]heptan-2-yl ester, Isomer B, prepared in Example 8, Step 1, was saponified as described in Example 2, Step 2, to give 327 mg (41.3%) of the pure acid as a white solid, m.p. 171°-172° C.
Anl. Calcd. for C 22 H 23 NO 3 : C, 75.62; H, 6.63; N, 4.01 Found: C, 75.55; H, 6.42; N, 4.31.
[α] D 25 =-60.3°.
TABLE II__________________________________________________________________________ Substituted 1,3,4,9-Tetrahydropyrano[3,4-b]indole Acetic__________________________________________________________________________Acids ##STR9## MeltingExampleR.sup.1 R.sup.2 R.sup.3 R.sup.4 R.sup.5 Isomer Point °C.__________________________________________________________________________ 1 Et CHCHCHCH H H A 145-147 2 Et CHCHCHCH H H A -- 3 Et CHCHCHCH H H B 171-173 4 Et CHCHCHCH H 8-C.sub.2 H.sub.5 A 147-148.5 5 Et CHCHCHCH H 8-C.sub.2 H.sub.5 B 158-159.5 6 Et H H 7-F 8-CH.sub.3 A 159-160 7 Et H H 7-F 8-CH.sub.3 B 138-140 8 Et CHCHCHCH H H A(+) 170-171.5 9 Et CHCHCHCH H H A(-) 171-17210 Et H H 7-F 8-C.sub.2 H.sub.5 A 91-93.511 Et H H H 8-C.sub.2 H.sub.5 B 118-119.512 Et H H H 8-n-C.sub.3 H.sub.7 A 99.5-101.513 Et H H H 8-n-C.sub.3 H.sub.7 B 117-12014 Et H H H H A 133-13815 Et H H H H B 136-14116 Et H H 7-Cl 8-CH.sub.3 A 168-16917 Et H H 7-Cl 8-CH.sub.3 B 124-12618 Et CHCHCHCH 7-Cl 8-Cl A 154-15519 Et CHCHCHCH 7-Cl 8-CH.sub.3 A 158-15920 Et CHCHCHCH 7-Cl 8-CH.sub.3 B 218-22021 Et CHCHCHCH H 8-CH.sub.3 B 174-17622 Et CHCHCHCH H 8-CH.sub.3 A 141-14323 Et CHCHCHCH 5-CH.sub.3 8-Cl A 151-15224 Et CHCHCHCH 5-CH.sub.3 8-Cl B 250-25225 Et CHCHCHCH 6-Br H A 154-155.526 Et CHCHCHCH 6-Br H B 156-158.527 Et H H 6-F H B 145-14728 Et CHCHCHCH 6-F H B 190-19229 Et CHCHCHCH 5-Cl 8-CH.sub.3 A 172-17330 Et CHCHCHCH 5-Cl 8-CH.sub.3 B 248-25031 Propyl CHCHCHCH H H A 139.5-14132 Propyl CHCHCHCH H H B 172-17333 Et CHCHCHCH H 7-Cl B 186.5-18834 Et CHCHCHCH H 7-Cl A 152.5-15435 Et CHCHCHCH 5-CH.sub.3 8-CH.sub.3 A 175-17736 Et CHCHCHCH 5-CH.sub.3 8-CH.sub.3 B 230-23237 Et H H H 8-CH.sub.3 A 135-13738 Et H H H 8-CH.sub.3 B 138-13939 Methyl CHCHCHCH H H A 157-158__________________________________________________________________________ ##STR10## MeltingExample R.sup.1 Y R.sup.4 R.sup.5 Isomer Point °C.__________________________________________________________________________40 C.sub.2 H.sub.5 4-Cl H H A 182-18441 C.sub.2 H.sub.5 4-OCH.sub.3 H H B 163.5-164.542 C.sub.2 H.sub.5 4-Cl H H B 187.5-19043 C.sub.2 H.sub.5 4-F H H A 126-12844 C.sub.2 H.sub.5 3-CF.sub.3 H H B 164.5-16645 C.sub. 2 H.sub.5 2,4-diF H H A 150-151.5__________________________________________________________________________
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Indole derivatives characterized by having a 1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid nucleus bearing a substituent in position 1 and 4. The nucleus may be optionally substituted at positions 5, 6, 7 and 8. The derivatives are useful anti-inflammatory and analgesic agents and methods for their preparation and use are also disclosed.
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FIELD OF THE INVENTION
This invention generally relates to Lateral Insulated Gate Bipolar Transistors (LIGBTs), for example in integrated circuits (ICs), and methods of forming an LIGBT.
BACKGROUND TO THE INVENTION
Power devices operated in integrated circuits typically operate with a voltage in the range 20V to 1.2 kV and typically higher than 30V or 50V or so. Power devices typically operate with a current in the range 10 mA to 50 A and typically higher than 0.1 A and smaller than 5 A. Such devices may also be referred to as “high voltage/power devices”. These devices are typically capable of delivering from a few mWatts to 1 Watt or even a few tens of Watts of power. Their application may range from domestic appliances, electric cars, motor control, and power supplies to RF and microwave circuits and telecommunication systems.
Lateral devices in integrated circuits have the high voltage/low voltage main terminals (variously called the anode/cathode, drain/source and emitter/collector) and the control terminal (termed the gate or base) placed at the top surface of the device in order to be easily accessible. In addition the back surface is usually electrically connected via a metal enriched epoxy and a lead frame, usually made of copper, to ground. This is referred to as the back terminal. The epoxy is used as a package die attach and is enriched with particles of metal (e.g., silver) to increase its thermal conductivity and allow good thermal dissipation of heat from the silicon device to the package. In power ICs, such devices are often monolithically integrated with CMOS-type or BiCMOS-type low voltage and/or low power circuits and therefore it is desirable that the lateral high voltage devices are CMOS compatible. It is also possible that several high voltage, power devices are integrated within the same chip. (It will be appreciated that terms such as “top” and “bottom”, “above” and “below”, “lateral” and “vertical”, “beneath”, and “under” and “over” may be used in this specification by convention and that no particular physical orientation of the device as a whole is implied).
MOS bipolar power devices, such as the lateral insulated gate bipolar transistor (LIGBT) shown in FIG. 1 , are based on MOS control with bipolar current conduction in the drift layer and the lowly-doped substrate underneath. Such devices are based on the conductivity modulation concept. At high levels of charge injection, when the current in the device increases, a mobile charge of electrons and of holes is built up in the drift layer, and deep into the substrate region leading to a desirably sharp increase in the conductivity of the drift layer. The mobile charge accumulated, known as plasma, in the on-state dictates the on-state/switching performance of the device given that the plasma must be removed in order to switch the device to the off-state. The plasma level is one to three orders of magnitude higher than the doping level, depending on the current density and the lifetime of the carriers.
Van der Pol et al., Microelectronics Reliability, Volume 39, Issues 6-7, Pages 863-868 (June-July 1999) describes medium power, complementary bipolar devices that have no drift region and whose active transistors are vertically-oriented. Furthermore, a lower, substrate region of the IC does not form a part of the active device—the devices are actually isolated from such lower regions of the IC.
There remains a need for an LIGBT having improved characteristics, for example proper functioning, lower losses and/or faster switching over a wider range of operating conditions (e.g., any combination of one or more predetermined range of continuous and/or switching current between main terminals, voltage between main terminals, junction and/or ambient temperature, etc.).
For use in understanding the present invention, the following disclosures are referred to:
U.S. Pat. No. 7,381,606 (corresponding to application U.S. Ser. No. 11/783,966, which is related to application U.S. Ser. No. 11/133,455 (U.S. Pat. No. 7,301,220)), F. Udrea, Cambridge Semiconductor Ltd., published Mar. 20, 2008; WO-A-02/25700, Udrea, Cambridge Semiconductor Ltd., published 2006 Mar. 2; U.S. Pat. No. 6,703,684, Udrea, Cambridge Semiconductor Ltd., published Apr. 11, 2002; US-A-2004-0084752, Udrea, Cambridge Semiconductor Ltd., published May 6, 2004; US-A-2004-0087065, Udrea, Cambridge Semiconductor Ltd., published May 6, 2004; Microelectronics Reliability Vol. 39, Issues 6-7, June-July 1999, Pages 863-868, European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, J. A. van der Pol et al.
SUMMARY
According to a first aspect of the present invention, there is provided an LIGBT comprising: a substrate region of first conductivity type and peak dopant concentration less than about 1×10 17 /cm 3 ; a lateral drift region of a second, opposite conductivity type adjacent the substrate region and electrically coupled to said substrate region; a charge injection region of the first conductivity type to inject charge toward said lateral drift region; a gate to control flow of said charge in said lateral drift region; metal enriched adhesive below said substrate region; and an intermediate layer below said substrate region to substantially suppress charge injection into said substrate region from said metal enriched adhesive. The suppression of charge injection into said substrate region may be from a Schottky barrier between said substrate region and said metal enriched adhesive. In the complete absence of the intermediate layer, such a Schottky barrier may be formed by contact between the substrate region and said metal enriched adhesive.
The following paragraphs describe optional features, which may be applied in any combination in this or any of the other aspects of the invention described herein.
The substrate region may be a region doped differently from surrounding regions, e.g., the drift region, formed monolithically within the same wafer substrate. The preferred substrate region doping level may depend on application-specific requirements concerning, e.g., required withstand voltage, price of wafers (both higher for lower doping) and so on. More preferred peak doping concentrations of the substrate region are less than 1×10 16 /cm 3 , e.g., about 1×10 14 /cm 3 to about 1×10 15 /cm 3 .
The drift region as shown in the drawings is above the substrate region.
The charge injection region, which may be connected directly to a terminal on a surface of the LIGBT body, may be a p+ region, and/or may be located in a well, e.g. n-well.
The LIGBT may further have a semiconductor well region within which a region of said second conductivity type may be formed. The charge flow control may control conductivity in a channel region between the drift region and such a region of said second conductivity type within the semiconductor well region.
The adhesive below the substrate region refers generally to the LIGBT in use with the anode, cathode and gate terminals on the top, and does not imply orientation of the device as a whole (as earlier clarified). Moreover, and as described in more detail below, the adhesive, e.g. epoxy, may be attached to the substrate region directly or via one or more intervening layers/regions such as a semiconductor layer of the same conductivity type but more highly doped than the substrate region, a metal layer, an insulating layer and/or dielectric layer. (As for all instances of “attached” in this specification, the attachment is preferably direct or, less preferably, indirect, e.g., via intervening layers and/or regions).
The suppression may suppress (reduce or completely prevent) the charge injection as such into the substrate region and/or may suppress formation of a Schottky barrier between said substrate region and said metal enriched adhesive. For example, the suppression may reduce depletion region width and/or energy barrier height of a Schottky contact so that the contact becomes nonrectifying or even substantially (preferably completely) ohmic. Suppression of charge injection as such may be achieved by trapping charge from the adhesive before the charge reaches the substrate region, e.g., by recombination in a highly doped region adjacent the adhesive, or by blocking charge from reaching the substrate region, e.g., by using an electrically insulating layer. Suppression of formation of a Schottky barrier as such may be achieved by using an electrically insulating or metal layer, and/or by appropriate doping of a semiconductor layer between substrate region and the adhesive. In the case of using a metal layer as the intermediate layer, the metal preferably has work function relative to the substrate region to provide a nonrectifying contact as further described below, in particular as described in relation to the third aspect.
The suppression may inhibit action or presence of a parasitic thyristor comprising such a Schottky contact.
The suppression of charge injection and/or Schottky barrier formation may be achieved in at least one predetermined mode or all modes of operation of the LIGBT. The ‘all modes’ may comprise all (e.g., 1 or more) modes of operation of the LIGBT required by the intended application of the LIGBT. Any one or more of these modes(s) may cover a predetermined range of operating conditions defined by, e.g., any one or more predetermined values or ranges of: ambient temperature, junction temperature (e.g. −55 Celsius to 125 Celsius, greater for automotive devices, etc), on-state continuous drift region current (e.g. 10 mA to 50 A), on-state switching (e.g., pulsed) current, switching (e.g., pulsed) voltage and/or continuous forward and/or reverse voltage levels, e.g., between the anode and cathode terminals (e.g. 20 Volts to 1200 V, or higher). Thus, the at least one predetermined mode may be one such mode defining a range or specific value(s) of condition(s). For example, such a mode (which may be the only mode of ‘all modes’) may be defined by a 20 deg C. ambient temperature and/or, 0.1 A, 0.2 A or 0.5 A of switching or continuous on-state drift region current, which may be a maximum operating current of the LIGBT.
Further in this regard, an LIGBT of or formed by any of the aspects of the invention may be a high power device, for example having at least one operating mode (e.g., the predetermined mode above) with a continuous or switching current in the range 10 mA to 50 A and typically higher than 0.1 A and smaller than 5 A. In any operating mode(s), such a high power device may be capable of delivering from a few (e.g., 1-10) mWatts to 1 Watt or even a few tens of Watts (e.g., 10-50 W or up to 90 W) of power.
‘Switching’ generally refers to turning on/off conduction of cathode/source-anode/drain current in the device, i.e., of lateral current through the drift region. Thus, switching voltage and switching current of the device may be voltage and current, respectively, existing between the cathode/source and anode/drain when the device is pulsed on, generally under control of the gate voltage.
The electrical coupling between the drift region and substrate region may allow current derived from the charge injection region to flow laterally through both the substrate region and the drift region, to be collected at a charge collection region e.g. a contact region connected to a cathode/source terminal. (The charge injection region may be connected to an anode/drain terminal). Such electrical coupling may generate plasma in the substrate region as well as in the drift region.
(“Contact region” throughout this specification is generally a region at a surface of the LIGBT for electrical connection, preferably ohmic, to a terminal having, e.g., a line, wire, bonding pad, etc., and is generally for charge collection from or charge injection into the LIGBT, e.g., may be a charge collection semiconductor region or a charge injection semiconductor region; such a contact region may be the charge injection region of the first conductivity type).
The intermediate layer may comprise a semiconductor layer of the first conductivity type (e.g. about 1 um thick) and having higher peak dopant concentration (e.g., about 1000 times higher) than said substrate region. This may result in the above recombination of carriers with oppositely charged carriers in the semiconductor layer, e.g., recombining electrons from the adhesive (e.g. epoxy) with holes in the semiconductor layer, so capturing the injected electrons. The semiconductor layer is preferably an implanted layer, i.e., doped within the same monolithic substrate in which the substrate region is provided (this may be the case particularly in a bulk silicon device embodiment). For example, the semiconductor layer is a p+ layer formed using a cold implanting process, e.g., involving a quick thermal anneal to avoid melting of metallisation on the device.
The LIGBT may further comprise a metallic layer between said semiconductor layer and said adhesive. The metallic layer may comprise, e.g., gold or platinum; aluminium may be less suitable as this may give a Schottky barrier when in contact with a silicon substrate region having low doping concentration of, e.g., less than 1×10 17 /cm 3 , though this may be overcome if the aluminium is provided in an alloy.
The intermediate layer may comprise a metallic layer between said substrate region and said adhesive, with or without the above semiconductor layer.
Additionally or alternatively to the semiconductor and/or metallic layer(s), the intermediate layer may comprise an electrically insulating layer, e.g., a dielectric layer, preferably <2 um thick (e.g., 0.1-0.2 um), such as silicon nitride or silicon oxide, the nitride and/or oxide preferably being suitable for low temperature deposition.
The LIGBT may comprise a pnp transistor having an emitter comprising the charge injection region (e.g., p+) connected to an anode terminal, a base of said pnp transistor comprising the drift region (e.g. n−), and a collector region comprising the substrate region (e.g. p−).
The LIGBT may comprise a pnp transistor having an emitter comprising the charge injection region (e.g. p+) connected to an anode terminal, a base of said pnp transistor comprising a well region (e.g., n−), and a collector region comprising the substrate region, wherein said well region is preferably a buffer region of second conductivity type adjacent to the drift region (e.g. n−), said charge injection region located within said buffer region.
Regarding dimensions, the substrate region may be between 50 to 300 micrometers thick. The semiconductor layer may be between 500 nanometers and 5 micrometers in thickness. The insulating layer may have thickness less than 1 micrometer. The thickness of the drift region may be greater than 1 μm and preferably between 3 to 20 μm.
The semiconductor layer is preferably at least 100 times, more preferably at least 1000 times, more highly-doped than the substrate region (e.g. p−), e.g., may have a peak doping concentration higher than 1×10 16 cm −3 , preferably higher than 1×10 17 cm −3 .
The insulating layer may comprise an oxide layer (preferably low temperature oxide (LTO), e.g., for depositing at low temperature), a nitride layer and/or a combination of nitride and oxide on a back surface of the substrate region and adjacent to said adhesive.
A corresponding method of designing or substantially preventing a thyristor action in an LIGBT, the LIGBT having the above substrate region, lateral drift region, charge injection region, gate and metal enriched adhesive, may comprise selecting an intermediate layer to, when located below said substrate region, substantially suppress charge injection into said substrate region from said metal enriched adhesive.
There may further be provided an integrated circuit (IC) comprising the LIGBT of the first aspect (preferably having any combination or one or more of the above optional features) and at least one other, preferably CMOS-based, device.
According to a second aspect of the invention, there is provided a method of forming an LIGBT, the LIGBT comprising: a substrate region of first conductivity type and peak dopant concentration less than about 1×10 17 /cm 3 ; a lateral drift region of a second, opposite conductivity type adjacent the substrate region and electrically coupled to said substrate region; a charge injection region of the first conductivity type to inject charge toward said lateral drift region; a gate to control flow of said charge in said lateral drift region; and metal enriched adhesive below said substrate region, the method comprising forming an intermediate layer below said substrate region to substantially suppress charge injection into said substrate region from said metal enriched adhesive. The suppression may be of charge injection into said substrate region from a Schottky barrier between said substrate region and said metal enriched adhesive. As for all aspects comprising a said intermediate layer, this layer is between the substrate region and metal enriched adhesive. Where a metal layer is used as the intermediate layer, the metal preferably has a work function relative to that of the substrate region as defined below in relation to the third aspect.
Any one or more feature(s) each corresponding to one of the above optional features of the first aspect may be provided in this aspect in any combination.
Thus, the forming of an intermediate layer may comprise forming as said intermediate layer a semiconductor layer of the first conductivity type and having higher peak dopant concentration than said substrate region, preferably with a metallic layer between said semiconductor layer and said adhesive. Similarly, the forming of an intermediate layer may comprise forming as said intermediate layer a metallic layer between said substrate region and said adhesive, and/or forming as said intermediate layer an electrically insulating layer.
Such an insulating layer may be deposited at wafer level, e.g., after fabricating contact region(s) (e.g. the charge injection region of the first conductivity type) and/or metallization layer(s) (e.g., a terminal) at the top surface of the LIGBT.
The method may comprise adding said semiconductor layer at wafer level, e.g., after fabricating contact region(s) (e.g. the charge injection region of the first conductivity type) and/or metallization layer(s) (e.g., a terminal) at the top surface of the LIGBT. The method may comprise forming the LIGBT in a wafer and adding said semiconductor layer after thinning the wafer.
The method may comprise in the following order, fabricating the semiconductor layer, and fabricating a metallization layer attached to the semiconductor layer.
According to a third aspect of the present invention, there is provided an LIGBT comprising: a substrate region of first conductivity type and peak dopant concentration less than about 1×10 17 /cm 3 ; a lateral drift region of a second, opposite conductivity type above the substrate region, adjacent said substrate region and electrically connected to said substrate region; a charge injection region of the first conductivity type electrically coupled to said drift region; a first electrical connection to said charge injection region; a second electrical connection to said drift region to remove charge from said drift region; a gate connection between said first and second electrical connections; an intermediate layer beneath said substrate region; a metal-enriched adhesive layer beneath said intermediate layer; and a reference voltage connection beneath said metal-enriched adhesive layer, wherein said intermediate layer comprises one or more of: an electrically insulating layer; a semiconductor layer of said first conductivity type having a peak dopant concentration greater than a peak dopant concentration of said substrate region; and a layer of metal having a work function relative to a work function of said substrate region to provide a substantially (preferably completely) nonrectifying contact between said substrate region and said layer of metal. Preferably, the nonrectifying contact is substantially and/or completely ohmic.
(Corresponding methods may comprising designing or fabricating an LIGBT having each of the above components of the third aspect, or may be methods of designing or substantially preventing a thyristor action in an LIGBT, the LIGBT having the above components and the method comprising selecting an intermediate layer fulfilling the above criteria).
Where the substrate region is n-type, i.e., the first conductivity type is n-type, the work function of the metal is preferably substantially equal to (e.g., matching) or less than that of the substrate region.
Where the substrate region is p-type, i.e., the first conductivity type is p-type, the work function of the metal is preferably substantially equal to or greater than that of the substrate region.
The following paragraphs describe optional features of this aspect, which may be applied in any combination in any of the other aspects of the invention described herein.
The LIGBT is preferably a bulk silicon device, which may be advantageous for integration with other devices, in particular devices operating at different voltages, e.g. CMOS-based.
The electrical connection between the drift region and substrate region may allow current derived from the charge injection region to flow laterally through both the substrate region and the drift region as described above in relation to electrical coupling in the first aspect.
The first and/or second electrical connection may be a terminal, wire and/or bonding pad; this may further apply where the second electrical connection is coupled to the drift region if via a well/buffer region. The electrical coupling between the charge injection region and drift region may similarly be via an intervening region, e.g., a well/buffer region of the opposite conductivity type relative to that of the charge injection region.
The reference voltage connection, while generally for connection to ground, may in use alternatively be raised or lowered to a different potential.
The metal work function having a desired value relative to the work function of the substrate region may be achieved by selecting a metal having a work function taking into account to an energy band structure of the substrate region before contact with the metal, the structure representing, e.g., work function, electron affinity and/or band gap energy, Fermi level, etc. of the substrate region. The work function of the metal may be about 4-5 eV, e.g., 4.7 eV. Preferably, the work function is selected to (at least substantially) prevent formation of a Schottky barrier or to provide a depletion region that is sufficiently narrow that charge tunnels straight through the depletion region, the path between substrate region and adhesive preferably being ohmic.
A corresponding method forms or designs an LIGBT having the substrate region, the lateral drift region, charge injection region, first electrical connection, second electrical connection and gate connection, by forming or selecting an intermediate layer to provide over the metal-enriched adhesive layer for reference voltage connection, the method comprising one or more of: forming/selecting an electrically insulating material to form said intermediate layer; forming/selecting a semiconductor of said first conductivity type to form the intermediate layer and determining a peak dopant concentration of said semiconductor layer greater than a peak dopant concentration of said substrate region; and forming/selecting a metal (which may be a metal alloy) to form the intermediate layer, the metal having a work function relative to a work function of the substrate region to provide a substantially nonrectifying contact between said substrate region and said layer of metal.
According to a fourth aspect of the invention, there is provided a LIGBT, preferably as a bulk silicon device, comprising: a substrate region of first conductivity type and peak dopant concentration less than about 1×10 17 /cm 3 ; a lateral drift region of a second, opposite conductivity type above the substrate region; a charge injection region of the first conductivity type; metal enriched epoxy; and a parasitic thyristor having a carrier injection region formable by said charge injection region and a carrier injection region of the second conductivity type formed by said metal enriched epoxy, wherein said substrate region and charge injection region are configured to reduce charge injection from said second type carrier injection region into said substrate region such that the loop gain of the thyristor is less than unity in at least one predetermined operation mode, preferably in all operation modes. Thus, the thryristor, which is comprised of an npn transistor and a pnp transistor in thyristor configuration (see, e.g., FIG. 4 ) may be inactive or suppressed in such mode(s), loop gain being the sum of the current gain of the parasitic npn transistor, α p , and the current gain α n of the said pnp transistor. The loop gain <1 generally means that the thyristor loop current is not self-sustaining. Such a parasitic thyristor may in some embodiments actually be formed by said charge injection regions of the first and second conductivity types. (Corresponding methods may comprising designing or fabricating an LIGBT by selecting/forming each of the above components of the fourth aspect, or may be methods of designing or substantially preventing a thyristor action in an LIGBT, the LIGBT having the above components and the method comprising selecting the current gain α p and/or the current gain α n to provide the loop gain <1).
For example, the substrate and charge injection region are configured to reduce the charge injection by providing an intermediate layer (e.g., p+ and/or metallic and/or electrically insulating) between them as described previously in relation to the other aspects.
Similarly as described above, the epoxy may be attached to the substrate region, e.g., directly or via one or more intervening layers/regions which may comprise e.g. a semiconductor layer of the same conductivity type but more highly doped than the substrate region, a metal layer, and/or an electrically insulating layer. The ‘all modes’ of operation may be as described above in relation to the first aspect
Where the first conductivity type is p type, the LIGBT may comprise: at least one pnp transistor and a parasitic npn transistor, a said pnp transistor connected (directly or indirectly) to the parasitic npn transistor in a thyristor configuration to form said parasitic thyristor; a die attach formed by said metal enriched epoxy; and said parasitic npn transistor having an emitter-base junction formed by a Schottky contact between the metal-enriched epoxy die attach and the p-type substrate region, wherein the current gain of the parasitic npn transistor is such that the loop gain of said thyristor is less than unity in at least one predetermined operation mode of the LIGBT, preferably in all operation modes.
The Schottky contact may be at an interface between the surface and the attach, the interface forming a Schottky barrier. The die attach may comprise droplet(s) or other amount of thermo-setting silver epoxy for bonding, electrical and/or thermal connection of a wafer substrate surface of the LIGBT to a chip carrier.
The pnp transistor may have an emitter comprising a p type (e.g. p+) region (e.g., the charge injection region of the first conductivity type) connected to an anode terminal, a base of said pnp transistor comprising the n type (e.g. n−) drift region, and a collector region comprising the p type (e.g. p−) substrate region of peak dopant concentration less than about 1×10 17 /cm 3 .
The pnp transistor may have an emitter comprising a p region (e.g., p+; e.g., the charge injection region of the first conductivity type) connected to an anode terminal, a base of said pnp transistor comprising a well region (e.g. n−), and a collector region comprising the substrate region (e.g. p−) of peak dopant concentration less than about 1×10 17 /cm 3 , wherein said well region is preferably a buffer region of second conductivity type adjacent to the drift region, said charge injection region of the first conductivity type located within said buffer region.
The parasitic npn transistor may have an emitter comprising said metal-enriched epoxy die attach, a base comprising the p type (e.g., p−) substrate region of peak dopant concentration less than about 1×10 17 /cm 3 and a collector comprising the n type (e.g., n−) drift region.
The parasitic npn transistor may have an emitter comprising said metal-enriched epoxy die attach, a base comprising the p type (e.g., p−) substrate region of peak dopant concentration less than about 1×10 17 /cm 3 and a collector comprising an n type (e.g. n−) well region, wherein said well region is preferably a buffer region of second conductivity type adjacent to the drift region, said charge injection region of the first conductivity type located within said buffer region.
The LIGBT may comprise at the back surface of said substrate region adjacent to said metal enriched epoxy a p type (e.g., p+) layer having higher peak dopant concentration than said substrate region.
The p type layer (e.g., p+) having higher peak dopant concentration than said substrate region may be between 500 nanometers and 5 micrometers in thickness.
The p type (e.g., p+) layer having higher peak dopant concentration than said substrate region may be at least 100 times, preferably at least 1000 times, more highly-doped than the substrate region (e.g. p−) said higher dopant concentration preferably higher than 1×10 16 cm −3 .
The LIGBT may comprise a metallization layer attached to the p type (e.g., p+) layer having higher peak dopant concentration than said substrate region.
The LIGBT may comprise a (preferably thin) insulating layer such as a oxide layer (preferably low temperature oxide (LTO)), a nitride layer or a combination of a nitride and oxide, on a back surface of the substrate region and adjacent to said epoxy. The insulating layer may be deposited at wafer level, e.g., after contact region(s) (e.g. the charge injection region of the first conductivity type) and metallization layer(s) (e.g., terminal(s) at the top surface of the LIGBT are fabricated. The insulating layer may have thickness less than 1 micrometer.
The sum of the current gain of the above parasitic npn transistor, α p , and the current gain α n of the said pnp transistor (which may be described as vertical, as shown in the drawings) is preferably less than unity in all operational modes of the LIGBT. More specifically, the current gain of the parasitic npn transistor, α p may be less than 0.1 and even more preferably below 0.01.
The thickness of the drift region may be greater than 1 μm and preferably between 3 to 20 μm.
There may further be provided an integrated circuit (IC) comprising the LIGBT according to the fourth aspect and at least one other, preferably CMOS-based, device.
According to a fifth aspect of the invention, there is provided a method of forming an LIGBT, the LIGBT comprising: a substrate region of first conductivity type and peak dopant concentration less than about 1×10 17 /cm 3 ; a lateral drift region of a second, opposite conductivity type above the substrate region; a charge injection region of the first conductivity type; and metal enriched epoxy, whereby a parasitic thyristor having a carrier injection region is formable by said charge injection region and a carrier injection region of the second conductivity type formed by said metal enriched epoxy, the method comprising providing an intermediate layer between said substrate region and said second type charge injection region to reduce charge injection from said second type carrier injection region into said substrate region such that the loop gain of the thyristor is less than unity inactive in at least one predetermined operation mode of the LIGBT, preferably in all operation modes. In some embodiments, such a parasitic thyristor is actually formed by the charge injection region of the first conductivity type and that of the second conductivity type.
Any one or more feature(s) each corresponding to one of the above optional features of the fourth aspect may be provided in this aspect in any combination.
For example, the method may comprise: depositing as said intermediate layer an insulating layer such as an oxide layer, a nitride layer and/or a combination of a nitride and oxide, on to a back surface of the substrate region and adjacent to said metal-filled epoxy, wherein the insulating layer is deposited at wafer level, e.g., after contact region(s) (e.g. the charge injection region of the first conductivity type) and metallization layer(s) (e.g., terminal(s)) at the top surface of the LIGBT are fabricated.
The method may comprise forming at the back surface of said substrate region adjacent to said metal enriched epoxy a p type layer (e.g., p+) having higher peak dopant concentration than said substrate region, and comprising adding said p type layer (e.g., p+) having higher peak dopant concentration at wafer level, e.g., after contact region(s) and metallization layer(s) (e.g., terminals) at the top surface of the LIGBT are fabricated.
The method may comprise forming at the back surface of said substrate region adjacent to said metal enriched epoxy a p type layer (e.g., p+) having higher peak dopant concentration than said substrate region, and comprising forming the LIGBT in a wafer and adding said p type layer (e.g., p+) having higher peak dopant concentration after thinning the wafer.
The method may comprise forming at the back surface of said substrate region adjacent to said metal enriched epoxy a p type layer (e.g., p+) having higher peak dopant concentration than said substrate region, and comprising fabricating, in the following order, the p type layer (e.g., p+) having higher peak dopant concentration than said substrate region, and a metallization layer attached to the p type layer (e.g., p+) having higher peak dopant concentration.
The LIGBT of or formed by any of the above aspects of the invention may be a high power device, for example operating with a continuous or switching current in the range 10 mA to 50 A and typically higher than 0.1 A and smaller than 5 A. Such a high power device may be capable of delivering from a few (e.g., 1-10) mWatts to 1 Watt or even a few tens of Watts (e.g., 10-50 W or up to 90 W) of power.
Preferred embodiments are defined in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:
FIG. 1 shows a state of the art LIGBT;
FIG. 2 shows the positions of three pnp transistors (T 1 , T 2 and T 3 ) in an n-channel LIGBT such as that of FIG. 1 ;
FIG. 3 shows a parasitic thyristor formed by a parasitic npn transistor together with the vertical pnp transistor T 3 in the n-channel LIGBT;
FIG. 4 shows an equivalent electrical connection diagram of the n-channel LIGBT, showing the relationships between the three pnp transistors, T 1 , T 2 and T 3 and the parasitic npn transistor, Tp;
FIG. 5 shows I-V characteristics of a Schottky contact for different wafers processed in the same conditions;
FIG. 6 shows a p+ highly-doped layer added at the back surface of the lowly-doped substrate of the n-channel LIGBT of FIG. 3 , adjacent to said metal enriched epoxy;
FIG. 7 shows an extra metallization layer added to the n-channel LIGBT of FIG. 6 after the p+ layer is formed;
FIG. 8 shows I-V characteristics for a Schottky contact and for an ohmic contact; and
FIG. 9 shows a thin insulating layer deposited onto the back surface of the lowly-doped substrate of the n-channel LIGBT of FIG. 3 , adjacent to metal-filled epoxy.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The following describes arrangements falling within the broader aspects of the present invention summarised above, and more specific embodiments.
In an LIGBT device, a rated off-state breakdown of the device may be achieved by appropriate doping levels and dimensions of the drift layer and the substrate region. The presence of a lowly-doped substrate region below the drift region may help to distribute more uniformly the electric field and potential lines within the drift region and hence help to increase the voltage breakdown ability of the device. This is known as the RESURF effect. For an effective RESURF, the substrate region is preferably more lowly-doped than the drift region (e.g., by 5× to 10× times). Nevertheless the presence of an open substrate may have detrimental effects on the switching as plasma is deeply accumulated in the lowly-doped substrate and its removal during turn-off can take a long time and result in high turn-off losses.
In general, any embodiment of an LIGBT within the scope of the present invention such as those shown in FIGS. 6 , 7 and 9 , comprises at least two contact regions of a first conductivity type; at least one semiconductor well region; a region of a second, opposite conductivity type located within a said semiconductor well region of said first conductivity type; a lateral drift region of the second conductivity type to conduct charge from a first said contact region towards a second said contact region; and a gate to control conductivity in a channel region between said lateral drift region and said region of said second conductivity type within said semiconductor well region and to thereby control flow of said charge from one of said first and second contact regions to the other of said first and second contact regions.
More specifically, such a LIGBT may be an n-channel or p-channel LIGBT and may comprise: a first contact region of a first conductivity type located within a buffer region of a second conductivity type; a second contact region of said first conductivity type; a source region of said second, opposite conductivity type located within a well region of said first conductivity type and connected electrically to said second contact region; a lateral drift region of the second conductivity type located between the said well region and said buffer region, said lateral drift region to be depleted of mobile carriers during an off-state blocking mode of the LIGBT and able to conduct charge during an on-state conducting mode of the LIGBT; and an insulated gate placed above and in direct contact to said well region, said insulated gate to control charge in a channel region between said lateral drift region and said source region of said second conductivity type and to thereby control flow of charge within the said drift region.
A die attach metal-enriched epoxy may form a Schottky contact or Schottky barrier when in contact with the lowly-doped substrate region. The metal-enriched (metal-filled) epoxy becomes effectively a region of opposite conductivity to that of the lowly-doped substrate region, and may thus allow injection of minority carriers of opposite conductivity type to that of the substrate region when the Schottky contact is forward biased.
When coupled to other regions in the LIGBT, the Schottky contact may lead to the formation of a vertical parasitic thyristor that can slow down the turn-off process and/or introduce additional switching losses and/or, in the worst scenario, lead to latch-up (e.g., resulting in loss of gate control) often followed by thermal failure. (Additionally or alternatively in an LIGBT, other latch-up of LIGBTs may be associated with lateral parasitic thyristors which differ from the above vertical parasitic thyristor).
Embodiments of the invention are particularly concerned with high voltage semiconductor devices which can be used in power integrated circuits and have particular application to MOS-bipolar transistors. More specifically, some embodiments are LIGBTS that are high power devices employing a MOS gate, a drift region and a lateral pnp transistor and, in particular, which may have a lowly-doped substrate region. As understood from the description of embodiments below, advantages of these and other embodiments may include suppression of a parasitic thyristor that may otherwise cause slow switching and/or represent as a reliability hazard.
Any substrate region of an embodiment described herein may comprise a semiconductor such as silicon.
One arrangement of a lateral insulated gate bipolar transistor comprises a lowly-doped substrate region of first conductivity type, a drift region of second conductivity type, placed above the substrate region, a charge injection region of first conductivity type, preferably located within a buffer region of second conductivity type, adjacent to the drift region, a parasitic thyristor, having one of the first type carrier injection regions formed by said charge injection region and the second type carrier injection region formed by a metal enriched epoxy attached to the lowly-doped substrate region and further attached to a package, whereby the injection from said second type carrier injection region is effectively suppressed, such that the thyristor is inactive in all operation modes. In a first embodiment of the arrangement a highly doped layer of first conductivity type is formed by or at least partially within the lowly-doped substrate region adjacent to said metal enriched epoxy. The highly doped layer may have at least either or both of the following two roles, both ultimately suppressing the injection of carriers of second conductivity type from the metal enriched epoxy (for example, n-type semiconductor and electrons being of one conductivity type, and similarly, p-type semiconductor and holes being of another conductivity type, the one and another being opposite): firstly it is acting as a recombination region, effectively ‘capturing’ the carriers of second conductivity type within it and (ii) it allows to form a more ohmic contact, through tunnelling, as opposed to a Schottky contact to the metal enriched epoxy. In a second embodiment of the arrangement, a thin insulating layer is introduced between the lowly-doped substrate region and the metal enriched epoxy to preferably completely suppress said thyristor.
An LIGBT, in the configuration shown in FIG. 1 can be broadly regarded (in terms of an equivalent circuit) as a low voltage MOS component driving three bipolar transistors (i) a wide base (high voltage) bipolar transistor, with the base being formed by the n− drift region, (ii) a narrow base wide collector transistor with the collector being formed by part of the lowly-doped substrate region, the collector terminal being one of the main top surface terminals, and (iii) a narrow base wide collector transistor with the collector being formed by another part of the lowly-doped substrate, the collector terminal being the said back terminal attached to the metal enriched epoxy. By way of example, an n-channel LIGBT has an n-channel MOSFET driving the base of (i) a ‘lateral’ wide base pnp transistor (ii) a vertical narrow base pnp transistor with collector terminal being one of the main top surface terminals and (iii) a vertical narrow base pnp transistor with collector terminal being the back terminal. The positions of the three pnp transistors (T 1 , T 2 and T 3 , respectively) are shown schematically in FIG. 2 .
As already mentioned, given that the p− substrate is lowly-doped, the contact between this metal-filled epoxy and the substrate may not be ohmic and may form a Schottky barrier. The metal (e.g., silver)-enriched epoxy may then act as a source of electrons (in a similar way to an n type layer) becoming the emitter of a parasitic npn transistor formed between the metal (silver)-filled epoxy (as emitter), the lowly-doped substrate region (as base) and the drift region and/or n-well buffer region (as collector). This parasitic npn transistor together with the vertical pnp transistor T 3 form a parasitic thyristor as shown in FIG. 3 . It is therefore very preferable that this thyristor is inhibited at all times, since as already mentioned before, its operation could slow down the device during turn-off and/or possibly lead to latch-up and/or ultimately thermal failure.
FIG. 4 presents schematically an equivalent electrical connection diagram, showing the relationships between the three pnp transistors, T 1 , T 2 and T 3 and the parasitic npn transistor, Tp. T 3 and Tp form a parasitic thyristor characterised by a positive feedback (base and collector terminals are connected to each-other reinforcing the current loop). Furthermore, all the three pnp transistors share the same emitter and base, being respectively the p+ region connected to the anode/drain terminal and the n-well buffer region and/or n-drift region. However the collector of each pnp transistor relates to a different region of the LIGBT: the collector of the lateral pnp transistor, T 1 , is formed by the p-well region, connected to the cathode/source terminal via the p+ short region. The collector of T 2 is formed by the lowly-doped p-type substrate, and is dominated by the region of that substrate which is closer to the p-well region, connected to the cathode/source terminal via the p+ short region. The collector of T 3 is also formed by the p-type substrate, however it is dominated by the region of that substrate lying further from the p-well region. This region of the substrate is connected to the back terminal of the LIGBT via the metal-filled epoxy and through the Schottky contact. Effectively the collector terminal is connected to the base of the parasitic npn transistor Tp.
The Schottky contact is a non linear contact and its barrier height varies from wafer to wafer, from lot to lot, and from one epoxy to another. It is a parasitic contact and its characteristics are often unpredictable. FIG. 5 shows the I-V characteristics of this contact for different wafers processed in the same conditions. It can be clearly seen that the contact can vary a lot from one chip made in one wafer to another made in a different wafer. The presence of this non-linear contact in the LIGBT can lead to additional switching losses via a parasitic thyristor, and/or can even lead to latch-up (and sometimes eventually thermal failure).
Furthermore the presence of the vertical pnp transistor T 3 may be beneficial to the trade-off between the on-state and switching losses. Its gain should preferably be adjusted so that this trade-off is favourable for a particular application. Nevertheless, in principle and generally, the thinner the p− substrate region, the thinner the collector region of T 3 and the faster the turn-off and the lower the losses. However thinning down T 3 also means a shorter base for the parasitic npn transistor and hence a more active thyristor.
It is therefore an advantage of an embodiment to suppress or drastically minimise the effect of this non-linear contact and hence suppress the action of the parasitic thyristor in all operation modes.
In a first arrangement, a lateral insulated gate bipolar transistor that comprises a lowly-doped substrate of first conductivity type, a drift region of second conductivity type, placed above the substrate, a charge injection region of first conductivity type, preferably located within a buffer region of second conductivity type, adjacent to the drift region, a parasitic thyristor, having one of the first type carrier injection regions formed by said charge injection region and the second type carrier injection region formed by a metal enriched epoxy attached to the lowly-doped substrate and further attached to a package, whereby the injection from said second type carrier injection region is significantly lowered or effectively suppressed, such that the thyristor is inactive in all operation modes.
In a second arrangement, a Lateral Insulated Gate Bipolar Transistor (LIGBT) comprising at least one pnp transistor, said at least one of the pnp transistors being connected to a parasitic npn transistor in a thyristor configuration, said parasitic npn transistor having the emitter/base junction formed by a Schottky contact between a metal-enriched epoxy used as die attach for the package and a lowly-doped p-type substrate wherein the current gain of the parasitic npn transistor is considerably lowered or completely annulled such that said thyristor is inactive in each and all operation modes preferably including extreme conditions of operation. The said at least one pnp transistor has the emitter formed by the p+ region connected to the anode/drain terminal, the base formed by the n-drift region and/or n-well region, if present, and the collector region formed by the p− lowly-doped substrate. The parasitic npn transistor has the emitter formed by said metal-enriched epoxy, the base formed by the lowly-doped p-type substrate and the collector formed by the n-drift region and/or n-well region if present.
Preferably the metal used to enrich the epoxy for thermal/electrical conduction is silver. Examples of such silver enriched epoxies are Epotek H20E, Ablebond 2600AT and 84-1 LMI and their thermal conductivities are 29 W/mK, 20 W/mK and 2.4 W/mK respectively.
Preferably, a p+ highly-doped layer is added at the back surface of said lowly-doped substrate adjacent to said metal enriched epoxy, as shown in FIG. 6 . This layer may have a double role: (i) it facilitates tunnelling of holes from the lowly-doped p− type substrate to the metal-enriched epoxy and thus suppresses the Schottky contact and (ii) it acts as a barrier to electrons from reaching the n-drift region, where they can act as a base current for the said vertical pnp transistor. Both these features alone or in combination may result in considerably lowering the gain of the parasitic npn transistor.
Preferably, the said p+ highly-doped layer is added at wafer level, after the top regions and the formation of metallization layers at the top surface are carried out, and before the die is diced and attached to the package with the help of the metal-filled epoxy.
Preferably, the said p+ highly-doped layer is added after the wafer is thinned down (by grinding and/or chemical-mechanical polishing). The thinning down may: (i) help to reduce the thermal path from the top regions to the back surface and thus allows favourable heat dissipation; (ii) allow higher turn-off speed and lower switching losses as there is a less resistive access to the plasma stored at the top of the highly-doped layer or lowly-doped substrate region; and/or (iii) help confine the plasma in a smaller volume, further reducing the turn-off time and switching losses.
Preferably the thinning down of the substrate leads to a total thickness of the p-type substrate between 50 to 300 micrometers, and from a mechanical/electrical/thermal trade-off perspective, between 100 to 250 micrometers.
Preferably, the said p+ highly-doped layer is of the order of hundreds of nanometers to a few micrometers in thickness.
Preferably the said p+ highly-doped layer is one or more orders of magnitude more highly-doped than the p− layer substrate.
Preferably the said p+ highly-doped layer has a peak doping concentration higher than 1×10 16 cm −3 .
An extra metallization layer may be added after the p+ layer is formed, at the wafer level stage (before dicing and attaching the die to the package), as shown in FIG. 7 . This metal layer can further improve the non-linear contact leading to a pure ohmic contact (linear and reversible I-V characteristics as shown in FIG. 8 ). FIG. 8 shows a comparison between I-V characteristics for a Schottky contact (formed between the epoxy and the lowly-doped p-type substrate) and an ohmic contact (when a p+ and a metal layer are added between the lowly-doped p-type substrate and the epoxy). The metal layer can be a CMOS-compatible metal such as Aluminium, Tungsten, Titanium or alloys based on one of these or other CMOS-compatible metals.
Alternatively, a thin insulating layer such as a low temperature oxide (LTO), a nitride layer or a combination of a nitride and oxide layer is deposited onto the back surface of the lowly-doped substrate, adjacent to said metal-filled epoxy, as shown in FIG. 9 . This layer preferably completely suppresses the injection of electrons from the metal-filled epoxy and therefore preferably completely removes the existence of the npn parasitic transistor and the existence of the thyristor. This method may also remove the existence of vertical pnp transistor T 3 , as the thin insulating layer may remove the electrical connection to its collector. Therefore this embodiment may have a less favourable trade-off between on-state and switching performance than that using the p+ layer or the p+ layer and the subsequent metallization layer.
Preferably, the insulating layer is deposited (via chemical vapour deposition techniques) at wafer level, after the top regions and the formation of metallization layers at the top surface are carried out and before the die is diced and attached to the package with the help of the metal-filled epoxy.
Preferably, the insulating layer is very thin (below 1 micrometer) so that it does not add a considerable thermal resistance.
Preferably the current gain (e.g., h fe ) of the parasitic npn transistor, α p is less than 0.1 and even more preferably below 0.01. The sum of the current gain of the parasitic npn transistor, α p , and the current gain of vertical pnp transistor T 3 should be less than unity at all times, to avoid the break-over of the parasitic thyristor.
Preferably the Lateral Insulated Gate Bipolar Transistor (LIGBT) of any embodiment is used in power ICs monolithically integrated with other devices or CMOS circuits.
Preferably the Lateral Insulated Gate Bipolar Transistor (LIGBT) of any embodiment is used in conjunction with bulk CMOS technology or Junction Isolation technology where the n− drift region is formed inside a p-substrate. The single RESURF, double RESURF or multiple RESURF concepts may be used to increase the breakdown ability of the device.
Preferably, in any embodiment, the thickness of the drift region is greater than 1 μm and typically between 3 to 20 μm while the effective thickness through which the current flows, which includes the drift region thickness and part of the p-substrate thickness below it, is greater than 20 μm
Although the present specification mainly discusses a LIGBT (lateral Insulated Gate Bipolar Transistor), the principles of the present invention are also applicable to other lateral devices such as power/high voltage diodes (PIN diodes or Schottky diodes), power (or high voltage) bipolar transistors or thyristors.
No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto.
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This invention generally relates to LIGBTs, ICs comprising an LIGBT and methods of forming an LIGBT, and more particularly to an LIGBT comprising a substrate region of first conductivity type and peak dopant concentration less than about 1×10 17 /cm 3 ; a lateral drift region of a second, opposite conductivity type adjacent the substrate region and electrically coupled to said substrate region; a charge injection region of the first conductivity type to inject charge toward said lateral drift region; a gate to control flow of said charge in said lateral drift region; metal enriched adhesive below said substrate region; and an intermediate layer below said substrate region to substantially suppress charge injection into said substrate region from said metal enriched adhesive.
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FIELD OF INVENTION
[0001] The invention relates to polysulfonamide compositions for use as redistribution layers as used in the manufacture of semiconductors and semiconductor packages. More specifically it relates to photoimageable polysulfonamide compositions for redistribution applications. The invention also relates to the use of the compositions in semiconductor manufacture.
BACKGROUND OF THE INVENTION
[0002] An integrated circuit (IC) is a set of electronic circuits that are manufactured onto a semiconductor, notably silicon. ICs can be made very compact, having upwards of 10 million transistors or other electronic components per mm 2 and growing. As such the width and size of the conducting lines and interconnections used to connect the transistors and other components to the rest of the microcircuit need to be made smaller and smaller as the technology advances, currently tens of nanometers.
[0003] In some cases, when an IC, or microchip, is manufactured, electrical connections called leads are attached from the microchip to a package in which the chip resides using wire bonds. The package is then bonded to a circuit board using a number of techniques such as, J-wing, gull-wing and solder bump interconnects. Many layers of materials, both conductive and non-conductive, are required to interconnect the transistors of microchips to packages to circuit boards and the outside world. In these constructions, distribution layers are necessary.
[0004] A redistribution layer is an extra layer of wiring on the chip and/or package that enables electronic interconnection of the microchip to other microchips, to the package and/or to the circuit board, and can be many layers of varying thicknesses, and resolutions. Redistribution layers are also used in chip stacking technologies.
[0005] For example, redistributing IC bond pads before flip chip bumping has become a common process for interconnection. Bumping is a process using solder which is applied as a solder paste and reflowed to create a round ball, or bump, of solder. Redistribution layers allow solder paste bumping of die originally designed for wire bonding. Wire bonding of the IC provides connections only to the one dimensional periphery of the IC, while redistribution layers and bumping allows the connections to be distributed throughout the two dimensional surface of the IC. While stud bumps and plated bumps could tolerate the small size and close spacing (for example 100 micron square pads on 150 micron pitch) of wire bond pads, solder paste generally requires more than twice that spacing. Converting peripheral wire bond pads to an area array of solder-bump pads by redistribution overcomes that barrier.
[0006] In some applications, redistribution offers an attractive method to create distributed power and ground contacts. Redistributed pads also transform off-chip connections from chip scale to board scale, as an alternative to expensive multilayer substrates. Wafer-level chip-scale packages often redistribute to ball-grid array pads as their final external package connection.
[0007] More compelling needs have been driving redistribution. Advances in chip scale packaging, wafer-level packaging, and most recently, 3-D packaging and system-in-package, often require redistributed bond pads.
[0008] A redistribution layer consists of wiring for electronic interconnect, processed by electroplating, vapor deposition, electroless plating or combinations thereof. Redistribution layers also require materials with low dielectric properties to isolate and insulate the interconnect wiring. As chip and consequently packaging and redistribution layers are pushed to be smaller and smaller, the material properties need to be able to continue to insulate and isolate the interconnects. Also as the dimensions decrease, processing methods needs to address ease of manufacture, cost issues, repeatability, and control.
[0009] In many instances polyimide is being used as in distribution layers, as well as organosilicon, benzocyclobutane and other exotic and expensive materials, that each have their own level of complexity, both in synthesis and in processing.
[0010] Thus there is a need for improved materials and improved processes that are designed to meet the new and ever demanding integrated circuit technology, particularly in the area of redistribution.
BRIEF DESCRIPTION OF THE FIGURES
[0011] FIG. 1 shows an SEM picture of the results from the composition and processing of example 1.
[0012] FIG. 2 shows an SEM picture of the results from the composition and processing of example 2.
[0013] FIG. 3 shows an SEM picture of the results from the composition and processing of example 3.
SUMMARY OF EXEMPLARY EMBODIMENTS
[0014] Disclosed and claimed herein are novel photosensitive compositions for use as low dielectric materials suitable for redistribution layers. Also disclosed and claimed herein are methods of using the novel compositions including ink jet and dry film applications.
[0015] On a first embodiment, disclosed and claimed herein are photoimageable compositions comprising at least one first polymeric aryl sulfonamide having formula (1):
[0000]
[0016] wherein R 1 through R 8 are the same or different and are hydrogen, branched or unbranched, substituted or unsubstituted alkyl groups of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic group, substituted or unsubstituted fused aromatic or fused heteroaromatic group, substituted or unsubstituted cycloalkyl groups with or without one or more heteroatoms substituted into cyclic ring, halogens, chalcogens, pnictogens, oxides of sulfur, oxides of phosphorous, silicon, and oxides of silicon; Y is an aromatic group or a chain of aromatic groups, X is a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon; at least one crosslinking component; at least one photoacid generator, and at least one solvent, wherein the composition has a dielectric constant less than 4.0 when processed.
[0017] In a second embodiment, disclosed and claimed herein are composition of the above embodiment wherein Y is formula (2);
[0000]
[0000] wherein R 9 through R 16 is the same or different and is hydrogen, branched or unbranched, substituted or unsubstituted alkyl groups of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic group, substituted or unsubstituted fused aromatic or fused heteroaromatic group, substituted or unsubstituted cycloalkyl groups with or without one or more heteroatoms substituted into cyclic ring, halogens, chalcogens, pnictogens, oxides of sulfur, oxides of phosphorous, silicon, and oxides of silicon; and Y′ is a chemical bond, a carbonyl group, a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon.
[0018] In a third embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the first polymeric aromatic sulfonamide has a MW between about 20K and 200K and the composition is soluble in aqueous base, when the composition is coated and dried.
[0019] In a fourth embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the compositions further comprise at least one of a flexibilizer, a dissolution rate modifier, an adhesion promoter or a combination thereof.
[0020] In a fifth embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the compositions further comprise at least one second polymeric aryl sulfonamide having formula (1), wherein X is a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon; Y is formula (2); wherein R 1 through R 16 is the same or different and is hydrogen, branched or unbranched, substituted or unsubstituted alkyl groups of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic group, substituted or unsubstituted fused aromatic or fused heteroaromatic group, substituted or unsubstituted cycloalkyl groups with or without one or more heteroatoms substituted into cyclic ring, halogens, chalcogens, pnictogens, oxides of sulfur, oxides of phosphorous, silicon, and oxides of silicon; and Y′ is a chemical bond, a carbonyl group, a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon, wherein the at least one second sulfonamide has a solubility in alkaline developer higher than the at least one first polymeric aryl sulfonamide.
[0021] In a sixth embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the at least one photoacid generator comprises an onium salt compounds, a sulfone imide compound, a halogen-containing compound, a sulfone compound, a sulfonate ester compound, a quinone-diazide compound, or a diazomethane compounds, or a triphenylsulfonium salt.
[0022] In a seventh embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the at least one crosslinker comprises at least one of a glycidyl ether, glycidyl ester, glycidyl amine, a methoxymethyl group, an ethoxy methyl group, a butoxymethyl group, a benzyloxymethyl group, dimethylamino methyl group, diethylamino methyl group, a dibutoxymethyl group, a dimethylol amino methyl group, diethylol amino methyl group, a dibutylol amino methyl group, a morpholino methyl group, acetoxymethyl group, benzyloxy methyl group, formyl group, acetyl group, vinyl group or an isopropenyl group or one or more glycidyl ether groups attached to a novolac resin, a novolac, a polyhydroxystyrene, a polyacrylate, or a maleic anhydride ester-acid polymer.
[0023] In an eighth embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the at least one solvent comprises esters, ethers, ether-esters, ketones, keto-esters, hydrocarbons, aromatics, and halogenated solvents.
[0024] In a ninth embodiment, disclosed and claimed herein are compositions of the above embodiments wherein the at least one crosslinker comprises an acid sensitive monomer or polymer wherein the acid labile group may be at least one tertiary carbonyl group, one tertiary alkyl carbonate group or one vinyl ether group.
[0025] In a tenth embodiment, disclosed and claimed herein are processes for forming a redistribution layer containing the steps of providing a substrate, applying the composition of any one of claims 1 - 16 , to a desired wet thickness, using standard techniques such as spin coating, heating the coated substrate to remove a substantial portion of the solvent to obtain a desired thickness, imagewise exposing the coating to actinic radiation, removing the unexposed areas of the coating, and optionally heating the remaining coating, and optionally heating the imagewise exposed coating prior to removing the unexposed areas of the coating. The unexposed areas may be removed with an aqueous base developer such as tetramethylammonium hydroxide or a suitable organic solvent developer.
[0026] In further embodiments the compositions are applied using ink-jet technology or dry film techniques.
DETAILED DESCRIPTION
[0027] As used herein, the conjunction “and” is intended to be inclusive and the conjunction “or” is not intended to be exclusive unless otherwise indicated. For example, the phrase “or, alternatively” is intended to be exclusive.
[0028] As used herein, the term “and/or” refers to any combination of the foregoing elements including using a single element.
[0029] As used herein the terms “composition” and “formulation” are used interchangeable and mean the same thing.
[0030] As used herein the term solvent means a liquid medium into which one or more of the various components of the formulations are soluble, colloidally suspended, or emulsified.
[0031] As used herein the term aliphatic refers to branched or unbranched, saturated or unsaturated, cyclic or polycyclic alkanyl, alkenyl, or alkynyl groups and combinations such as, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclohexyl, adamantly, and the like. The aforementioned groups may have substituents attached to its chain and/or onto its side groups. They may also contain heteroatom substitution in the chain, such as, for example, a diethylene oxide group which contain an oxygen heteroatom in the chain. Heteroatoms include, for example, oxygen, sulfur, selenium, tellurium, nitrogen, phosphorous, silicon, germanium, boron, aluminum and the transition elements of the periodic table and their derivatives, such as SO, SO 2 , S x , SnH 2 , N x , and the like, wherein x can be 2-6.
[0032] As used herein the term heterocycle alone or in combination refers to optionally substituted aromatic mono-radicals containing from about 4 to about 22 skeletal ring atoms, wherein one or more of the ring atoms is a heteroatom independently selected from among oxygen, nitrogen, sulfur, phosphorous, silicon, selenium, tellurium, silicon, germanium, boron, aluminum and the transition elements of the periodic table and there derivatives, such as for example, S x , N x , SO, SO 2 and SiO 2 , but not limited to these atoms and the proviso that the ring does not contain two adjacent O or S atoms. Where two or more heteroatoms are present in the ring, in some embodiment, the two or more heteroatoms are the same and in some embodiments, some or all of the two or more heteroatoms are different. The term also includes optionally substituted fused and non-fused heteroaromatic radicals as described above having at least one heteroatom. In some embodiments, bonding to a heteroaromatic group is via a carbon atom of the heterocycle, and in some embodiments via the heteroatom of the ring. The heteroaromatic ring may be substituted on one or more or the carbon atoms or on one or more of the heteroatom when available. A fused heteroaromatic ring may contain between two to 4 fused rings. Heterocycles of the current disclosure include for example, the single ring, pyridyl; the fused rings, carbazolyl, benzimidazolyl, quinolinyl, acridinyl; and non-fused biheteroaryl, bipyridinyl. Further examples include furanyl, thienyl, oxazolyl, phenazinyl, benzofuranyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, benzothiphenyl, benzoxadiazolyl, benzotriazolyl, imidazolyl, pyridazyl, pyrmidyl, pyrazinyl, pyrrolyl, pyrazolyl, purinyl, phthalazinyl, pteridinyl, quinolinyl, quinazolinyl, quinoxalinyl, triazolyl, tetrazoyl, thiazolinyl, triazinyl, thiadiazolyl, and he like and their derivatives, such as for example, their oxides.
[0033] As used herein the phrase remove a substantial portion of the solvent refers to removing, by heat, at least 92% of the solvent from the composition after it has been heated.
[0034] As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
[0035] The photoimageable compositions of the current disclosure include at least one first polymeric aryl sulfonamide having formula (1):
[0000]
[0036] wherein R 1 through R 8 are the same or different and are hydrogen, branched or unbranched, substituted or unsubstituted alkyl groups of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic group, substituted or unsubstituted fused aromatic or fused heteroaromatic group, substituted or unsubstituted cycloalkyl groups with or without one or more heteroatoms substituted into cyclic ring, halogens, chalcogens, pnictogens, oxides of sulfur, oxides of phosphorous, silicon, and oxides of silicon; Y is an aromatic group or a chain of aromatic groups, X is a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon; at least one crosslinking component; at least one photoacid generator, and at least one solvent, wherein the composition has a dielectric constant less than 4.0 when processed. Y can be formula (2);
[0000]
[0000] wherein R 9 through R 16 is the same or different and is hydrogen, branched or unbranched, substituted or unsubstituted alkyl groups of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic group, substituted or unsubstituted fused aromatic or fused heteroaromatic group, substituted or unsubstituted cycloalkyl groups with or without one or more heteroatoms substituted into cyclic ring, halogens, chalcogens, pnictogens, oxides of sulfur, oxides of phosphorous, silicon, and oxides of silicon; and Y′ is a chemical bond, a carbonyl group, a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon.
[0037] The compositions of the current disclosure have a dielectric constant of less than about 4.0 after they are processed into redistribution layers so that the layers can act as insulators for microchip interconnections. Higher dielectric constants of the composition are useful in other areas of microchip fabrication.
[0038] In some aspects of the current disclosure the photosensitive compositions exhibit solubility when coated and dried and prior to exposure in aqueous developer compositions, in some cases aqueous base solutions, for example, in tetramethylammonium hydroxide (TMAH) solutions, in concentrations such as 2.38% wt/wt. For example, some compositions are formulated to have a pKa less than about 12.9 when coated and dried, depending on the developer and its strength. Components can be added to the composition to provide for desirable pKa's, either increasing the solvency or decreasing the solvency. In other aspects organic solvents can be used to develop the photosensitive compositions.
[0039] The first polymeric aromatic sulfonamide may have a suitable molecular weight between about 20K to 200K Daltons. Again the molecular weight can be altered to provide for targeted properties such as, foe example, solvency in the developer, higher or lower dielectric constant, flexibility, environmental stability and the like.
[0040] Photoacid generators (PAGs) useful in the current disclosure include PAGs disclosure well known in the industry and include, without limitation, onium salt compounds, such as sulfonium salts, phosphonium salts or iodonium salts, non-ionic compounds, sulfone imide compounds, halogen-containing compounds, sulfone compounds, oxime sulfonates, ester sulfonate compounds, quinonediazide compounds, diazomethane compounds, dicarboximidyl sulfonic acid esters, ylideneaminooxy sulfonic acid esters, sulfanyldiazomethanes, or a mixture thereof.
[0041] Crosslinkers useful for the current disclosure include, but are not limited to, aminoplasts such as monomeric or oligomeric melamines, guanamines, ureas, methylols, monomeric or oligomeric glycolurils, hydroxy alkyl amides, epoxy and epoxy amine resins, blocked isocyanates, and divinyl monomers. Further examples of useful crosslinking compounds are compounds with multiple vinyloxy groups which can act as vinyl ether terminated crosslinking agents. Other useful crosslinkers include epoxy materials such as bisphenol A-based epoxy compounds, bisphenol F-based epoxy compounds, bisphenol S-based epoxy compounds, the novolac resin based epoxy, poly(hydroxystyrene)-based epoxy compounds. Crosslinking polymeric additives may be used alone or in combination with each other depending on the desired properties of the final film. Crosslinking polymers, contain any of a number of the same or different crosslinking substituents, such as, for example, epoxy, hydroxy, thiols, amines, amides, imides, esters, ethers, ureas, carboxylic acids, anhydrides, and the like. Other examples of crosslinking groups include the glycidyl ether group, glycidyl ester group, glycidyl amino group, methoxymethyl group, ethoxy methyl group benzloxymethyl group, dimethylamino methyl group, diethylamino methyl group, dimethylol amino methyl group, diethylol amino methyl group, morpholino methyl group, acetoxymethyl group, benzyloxy methyl group, formyl group, acetyl group, vinyl group, isopropenyl group, and vinyl ether group.
[0042] Other useful crosslinkers include monomeric and polymers hydroxyl compounds as well as monomeric and polymeric phenolic or novolac compounds as well as polyacrylates and maleic anhydride ester-acid polymers. The hydroxyl groups may be protected with acid labile protecting groups. The protecting groups are removed from the hydroxyl group when subjected to acid treatment. In the current disclosure PAGs generate acids when exposed to actinic radiation of the proper wavelength. The acid then reacts to deblock the protected hydroxyl which is then free to crosslink into the composition. Acid labile groups are well known in the industry and include, but are not limited to, tertiary alkyl esters, tertiary alkyl carbonyls, t-alkyl carbonates, such as, for example t-butoxy carbonate, and the like.
[0043] Solvents useful for the current disclosure include, for example, esters, ethers, ether-esters, ketones, keto-esters, hydrocarbons, aromatics, and halogenated solvents, as well as solvents having one or more polar functional groups such as hydroxyl, ether, amide, ester, ketone, and carbonate, for example, two functional groups, which may be the same or different, such as two hydroxyl groups or one hydroxyl group and one ether group. Selected from the group consisting of polyol, glycol ether, diacetone alcohol, 2-pyrrolidinone, N-methylpyrrolidinone, ethyl lactate, propylene carbonate, 1,3-dimethyl-2-imidazolidindione, and alkyl esters, and any combination thereof.
[0044] For example, the polyol is selected from the group consisting of polyethylene glycol, polypropylene glycol, poly(ethylene-co-propylene glycol), polyvinyl alcohol, trimethylol propane, ethylene glycol, glycerin, diethylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol, pentaethylene glycol, 1,2-propylene glycol, 1,3-propanediol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, bis-2-hydroxyethyl ether, 1,4-butanediol, 1,2-butenediol, 1,4-butenediol, 1,3-butenediol, 1,5-pentanediol, 2,4-pentanediol, 2,4-heptanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-bis(hydroxymethyl)cyclohexane, 1,2-bis(hydroxyethyl)-cyclohexane, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, pentaerythritol, sorbitol, mannitol, and any combination thereof, and preferably the polyol is selected from the group consisting of polyethylene glycol, trimethylol propane, ethylene glycol, glycerin, diethylene glycol, tripropylene glycol, and any combination thereof,
[0045] A glycol ether selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol n-propyl ether, propylene glycol t-butyl ether, propylene glycol n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol n-propyl ether, dipropylene glycol t-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-propyl ether, tripropylene glycol t-butyl ether, tripropylene glycol n-butyl ether, ethyl cellosolve, methyl cellosolve, polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, methoxytriglycol, ethoxytriglycol, butoxytriglycol, 1-butoxyethoxy-2-propanol, and any combination thereof, and preferably, the glycol ether is selected from the group consisting of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and any combination thereof In embodiments of the invention, propylene glycol monomethyl ether is a humectant.
[0046] Other components of the composition may include, for example, at least one of a flexibilizer, a dissolution rate modifier, leveling agents, surfactants or an adhesion promoter. Flexibilizers include polyols of varying molecular weight, polyesters, polyhydroxy esters and the like. Adhesion promoters are well known in the industry and vary depending on the surface to which the composition is applied. For example, suitable adhesion promotors for a silicon surface are the epoxided silanes. Surfactants and leveling suitable for the current disclosed composition are the fluorinated surfactants as well as others well known in the art.
[0047] In some embodiments, dissolution rate modifiers may also be included in the currently disclosed compositions such as to aid in development of the unexposed areas of the coating when processed. They may range from materials with high pKa's, suitable for aqueous base developers, such as, for example, novolac resins, such as cresol-formaldehyde resins, and carboxylic acid containing materials, such as, for example, acrylic acid containing polymers. These modifiers can range in molecular weight from about 100 to about 100,000 Daltons.
[0048] In some embodiments dissolution rate inhibitors may be used to prevent the developer from attacking the portions of the coating which are cured. Examples include maleic acid containing polymers and co-polymers and which may be modified to include ester groups.
[0049] In other embodiments the dissolution rate modifier may be based on polymeric aryl sulfonamides having formula (1), wherein X is a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon; Y is formula (2); wherein R 1 through R 16 is the same or different and is hydrogen, branched or unbranched, substituted or unsubstituted alkyl groups of 1-16 carbon atoms with or without one or more heteroatoms substituted into the chain, substituted or unsubstituted aromatic groups, substituted or unsubstituted heteroaromatic group, substituted or unsubstituted fused aromatic or fused heteroaromatic group, substituted or unsubstituted cycloalkyl groups with or without one or more heteroatoms substituted into cyclic ring, halogens, chalcogens, pnictogens, oxides of sulfur, oxides of phosphorous, silicon, and oxides of silicon; and Y′ is a chemical bond, a carbonyl group, a chalcogen, pnictogen, oxide of sulfur, oxide of phosphorous, silicon, or oxide of silicon, wherein the at sulfonamide has a solubility in alkaline developer higher than that of the polymeric aryl sulfonamide used as the base polymer in the composition.
[0050] Typical ranges of the components (% wt/wt) of the photoimageable composition include polymeric aryl sulfonamide: 65%-86%, crosslinker: 8.5%-22%, flexibilizer, when present: 4.0%-20.0%, PAG: 0.8%-2.0%, dissolution modifier, when present: 0.8%-2.0%, adhesion promoter, when present: 0.8%-1.5%, and surfactant, when present: 0.04%-0.13%.
[0051] In other embodiments disclosed and claimed herein are processes using the currently disclosed photoimageable compositions. Providing a substrate, such as, for example, a silicon wafer, as is, or the wafer may be treated with a number of coatings including adhesion promotors, metal layers, oxide layers and the like. The wafer may also contain prefabricated structures such as other dielectric layers, or metal layers such as for example, copper, aluminum, gold, and the like. The current compositions are then applied to the surface of the substrate and coated using such techniques as spin coating, curtain coating, brush coating, dip coating and the like. The coating may be applied by ink-jet techniques in which case the full surface of the substrate may be coated or only portions of the surface may be coating as desired. In this technique structures as small as about 10 nm may be applied to the surface of the substrate. Coating thicknesses may be between 1-15 microns. Solvent is removed to less than about 92% by heating, such as, for example 90-110° C. for 1-3 minutes.
[0052] In other embodiments the compositions of the current disclosure may be first prepared as photoimageable dry film. In preparing the dry film, the composition is coated onto an optically transparent support, from 50 to 95% transparent to the desired actinic radiation being used to expose the photoimage composition, such as for example polyethylene terephthalate (PET) film, using such methods are roller coating or other well-known methods used to prepare dry film photoresists. Solvent is removed to about 92%. A protective polyethylene film is then used to cover the photosensitive composition. In use the polyethylene film is removed and the photoimageable composition side is placed onto the above described substrate generally using heat and pressure. The PET film may be left on and contact exposed or it may be removed for off-contact printing.
[0053] Once the substrate has been coated, the photoimageable composition is exposed with actinic radiation in a desired pattern. The radiation may be I-line (365 nm), G-line, H-line, UV, EUV, E-beam, visible or other actinic radiation well known in the art used for photolithography, for example 125 to 800 mJ/cm 2 . The coating may then optionally be heated to improve the curing of the exposed areas. The unexposed areas are then removed using a suitable developer, aqueous or organic solvent, as described above. The developer may be at room temperature or heated. The resulting structure may optionally be heated to increase the cure, for example, 175-250° C. for 1-5 minutes.
EXAMPLES
Example 1
[0054] 10 parts of the polymeric aryl sulfonamide (3) was added to 100 parts of cyclopentanone. 3.2 parts of Powderlink® 1174 from Eastman Chemical Company, 2.5 parts of CDR 3314 from King Industries, 0.3 parts of para-n-octyloxyphenyl, phenyl iodonium hexafluoroantimonate (OPPI), and 0.3 parts of poly(styrene-co-maleic anhydride) were admixed. The composition was spun coated onto a silicon wafer to 9.8 microns.
[0000]
[0055] The coated wafer was soft baked at 90° C. for 2 minutes. The wafer was exposed to 800 mJ/cm 2 of i-line (365 nm) radiation. The wafer was post exposure baked at 105° C. for 3 minute. The unexposed areas were removed using room temperature 2.38% TMAH solution. The resulting structures were then thermally cured at 175° C. for 1 hr to give the pattern shown in FIG. 1 .
Example 2
[0056] 10 parts of the polymeric aryl sulfonamide (3) was added to a blend of 50 parts of cyclopentanone and 50 parts of 2-heptanone, 1.5 parts of Powderlink® 1174, 1.0 parts of CDR 3314, 0.3 parts of Irgacure® 121, non-ionic oxime sulfonate from BASF, and 0.3 parts of poly(styrene-co-maleic anhydride) were admixed. The composition was spun coated onto a silicon wafer to 9.8 microns.
[0057] The coated wafer was soft baked at 90° C. for 2 minutes. The wafer was exposed to 150 mJ/cm 2 of i-line radiation. The wafer was post exposure baked at 105° C. for 5 minute. The unexposed areas were removed using room temperature 2.38% TMAH solution. The resulting structures were then thermally cured at 175° C. for 1 hour to give the pattern shown in FIG. 2 .
Example 3
[0058] Example 1 was repeated using Irgacure 103 non-ionic PAG in place of the ionic OPPI PAG. The wafer was processes and exposed to 240 mJ/cm 2 and post exposure baked at 105° C. for 3 minutes. The results are shown in FIG. 3 .
[0059] The processed compositions of the examples showed low temperature cure <250° C., aspect ratios of better than 1 in some cases 2.5:1, strong adhesion to copper, which is critical in redistribution layers, as copper is the current ubiquitous metal for interconnections. The processes features also passed environmental testing 1000 cycles of −55° C. to 125° C.
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The invention relates to polysulfonamide compositions for use as redistribution layers as used in the manufacture of semiconductors and semiconductor packages. More specifically it relates to photoimageable polysulfonamide composition for redistribution applications. The invention also relates to the use of the compositions in semiconductor manufacture.
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BACKGROUND OF THE INVENTION
1. Field of the Invention The field of invention relates to bathtub shield structure, and more particularly pertains to a new bathtub shield arrangement wherein the same is arranged for mounting to a bathtub to prevent water splashing from within the bathtub during a bathing event.
2. Description of the Prior Art The bathing of children and the like has typically associated therewith splashing relative to such child behavior during a bathing event. The instant invention is arranged to prevent water splashing from the bathtub onto an adjacent floor.
U.S. Pat. Nos. 3,942,197; 3,855,642; 4,620,332; and 4,888,835 are prior art examples of bathtub shield structure.
The instant invention attempts to overcome deficiencies of the prior art by providing for a shield structure arranged for mounting relative to the bathtub and permitting its lowering in a first position during non-use and storage and raising to a second position during a bathing event and in this respect, the present invention substantially fulfills this need.
SUMMARY OF THE INVENTION
In view of the disadvantages inherent in the known types of bathtub shield apparatus now present in the prior art, the present invention provides a bathtub shield arrangement wherein the same includes a pivotally mounted bathtub shield plate arranged for lifting to a raised orientation during a bathing event. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new bathtub shield arrangement apparatus and method which has many of the advantages of the prior art listed heretofore and many novel features that result in a bathtub shield arrangement apparatus which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any combination thereof.
To attain this, the present invention provides a shield member arranged for mounting onto the sidewall portion of a bathtub, wherein the shield member includes a splash guard plate pivotally mounted to the shield member to permit securement of the splash guard plate to the wall surfaces of the surrounding bathroom in a raised orientation.
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 herein after and which will form the subject matter of the claims appended hereto.
Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new bathtub shield arrangement apparatus and method which has many of the advantages of the prior art listed heretofore and many novel features that result in a bathtub shield arrangement apparatus which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any combination thereof.
It is another object of the present invention to provide a new bathtub shield arrangement which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new bathtub shield arrangement which is of a durable and reliable construction.
An even further object of the present invention is to provide a new bathtub shield arrangement which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such bathtub shield arrangements economically available to the buying public.
Still yet another object of the present invention is to provide a new bathtub shield arrangement which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Yet an even further object of the present invention is to provide a new bathtub shield member for mounting onto the sidewall portion of a bathtub, wherein the shield member includes a splash guard plate pivotally mounted to the shield member to permit securement of the splash guard plate to the wall surfaces of the surrounding bathroom in a raised orientation.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is an isometric illustration of the invention as installed within a bathtub area.
FIG. 2 is a cross sectional view, taken along the lines 2--2 of FIG. 1 in the direction indicated by the arrows.
FIG. 3 is an orthographic end view of the invention arranged for lifting from a lowered position to a raised position relative to the bathtub member.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and in particular to FIGS. 1-3 thereof, a new bathtub shield arrangement embodying the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described.
The bath tub 11 being positioned between two end walls or supports.
More specifically, the bathtub shield arrangement 10 of the instant invention is arranged for mounting to a bathtub 11 having a bathtub top wall 12. The invention 10 comprises at least one mounting plate 13 having pairs of spaced spring legs 14 extending substantially orthogonally and downwardly therefrom. Each leg 14 of each individual respective pair is biased toward one another to engage the side walls of the bathtub adjacent the bathtub top wall 12. A sealing cushion 15 is mounted to a bottom surface of the mounting plate 13, and a support flange 16 is mounted coextensively to the top surface of the mounting plate 13. The support flange may be comprised of a padding material 29 encapsulated by a resilient covering 29a to provide a cushioning surface against which a parent or other person may rest.
The support flange 16 includes a support flange side wall 17 having a hinge 18 operable to pivotally mount a splash guard plate 20 relative to the support flange side wall 17, in a manner as indicated in FIG. 2. A polymeric covering 19 is arranged for optional securement to a foam core 30 of the splash guard plate 20 such that the guard plate will float, or alternatively the splash guard plate 20 itself may be formed of polymeric water impermeable type rigid material which will sink. The splash guard plate 20 is formed with guard plate end walls 21, a top wall tube 22, and spaced first and second side walls 26 and 27. Each end of the top wall tube 22 is directed coextensively to a respective guard plate end wall 21, such that a suction cup 23 having a suction cup rod 24 is received through the top wall tube 22 to further rigidify the structure 10. It has been found that the suction cup is superior to other securement devices because suction cups work particularly well in the wet environment of the bathtub area and do not scratch or mar the surrounding tile or fiberglass.
As to the manner of usage and operation of the instant invention, the same should be apparent from the above disclosure, and accordingly no further discussion relative to the manner of usage and operation of the instant invention shall be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. Therefore, the foregoing is considered as illustrative only of the principles of the invention.
Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A shield member is arranged for mounting onto the sidewall portion of a bathtub, wherein the shield member includes a splash guard plate pivotally mounted to the shield member to permit securement of the splash guard plate to the wall surfaces of the surrounding bathroom in a raised orientation.
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BACKGROUND OF THE INVENTION
The present invention relates to band clamps and methods to reliably install such about securable objects. More particularly, the invention is concerned with band clamps having an installation marker for signaling that the band clamp is being and/or has been properly installed.
Band clamps are universal means of affixing tubular and similar products to other components and/or each other. The two most used types of band clamps are a worm gear clamp and a T-bolt clamp. Both of these clamp types use bolts to close and tighten the band loop.
In many cases, directly clamped objects, such as sleeves, are of a flexible hose type. Flexible objects need more clamp band travel to become fully secured. Such band clamps can be occasionally mis-installed by simple omission by the installer to tighten them properly. Probability of mis-installation is increased by the fact that a band clamp installation process does not usually, by itself, generate sufficient visual clues to be able to judge effectiveness of band clamp installation.
As can be seen, there is a need for an installation marker enabling better visualization of correctness of installation of band clamps.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a band clamp installation marker comprises a volume of displaceable material, and an optional stretchable reinforcement material disposed at or about the displaceable material, wherein the displaceable material is substantially disposed between a band clamp and a securable object so as to signal shortening of a band clamp loop by gradually visibly moving from underneath the band clamp next to it.
In another aspect of the present invention, a band clamp comprises a shortenable noose substantially made of a strong flat band, and a displaceable material of which a substantial portion is disposed between the band clamp and an object to be secured, and an optional stretchable material disposed within or about said displaceable material, wherein a portion of said displaceable material is adapted so as to part sidewise from underneath the band clamp next to it under a constricting action of all adjacent objects.
In a further aspect of the present invention, a band clamp comprises a displaceable material disposed under the band clamp, having width smaller or equal to that of the band clamp, so it can remain hidden from view at the onset of installation.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is perspective view of a band clamp with a marker located on a sleeve partially under a gear bolt and partially under a band of a worm gear band clamp according to an exemplary embodiment of the present invention;
FIG. 2 is cross-sectional view of the clamp joint taken along line 2 - 2 of FIG. 1 , showing cross-section of the tightened band clamp with displaced marker material supported underneath by a single layer of reinforcement and provided with contrasting color patch next to the bulged flexible sleeve and center tube;
FIG. 3 is cross sectional view taken along line 2 - 2 of FIG. 1 , showing the band clamp in a non-tightened configuration without contrast patch;
FIG. 4 is cross sectional view of a band clamp according to an alternate embodiment of the present invention with contrast patch, where the contrast patch is wider than the band;
FIG. 5 is a perspective view of a band clamp according to an alternate embodiment of the present invention with a convenience bracket and pre-bent clamp accommodating the marker;
FIG. 6 is perspective view of displaceable material used in the band clamp of FIG. 1 where the grid represents optional stretchable reinforcement material; and
FIG. 7 is a flow chart describing a method according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
Various inventive features are described below that can each be used independently of one another or in combination with other features.
Broadly, embodiments of the present invention provide a band clamp with an installation marker made of displaceable material placed circumferentially at a strategic visible location, for example at or near the tightening element of a clamp, such as a bolt or another fastening device. The marker is located radially between the band of the clamp and a clamped object such as, for example, a flexible sleeve. The marker is adapted to respond to the state of band constriction about the object being clamped by flashing or hiding a colored patch of marker material, or by raising sidewise up (flagging). When the band clamp is being tightened, material of the marker is substantially displaced out of an initial position between the band clamp and the clamped object. Appearance of this material may signal that the band clamp is becoming or has already become satisfactorily tightened. In some embodiments, a contrasting colored underlying material, wider than the band clamp, may be also disposed under the band clamp and, as the band clamp becomes tightened, the displaceable material is squeezed out sidewise from underneath the band clamp, gradually masking view of the contrasting colored under material. This way, a visual impression of a vanishing patch of color may be achieved, signaling that the installation has been completed. In other embodiments, a containment bracket may be disposed between the marker and the clamped object so as to decrease the overall number of parts to be simultaneously handled during installation. The band above such containment bracket may be also pre-bent to more precisely accommodate the marker. In certain embodiments, the marker may be pre-shaped, for example to be sickle-like, so as to provide uniform distribution of transversal clamping load at the clamped object.
Certain embodiments may use a transversally placed marker, not quite initially hidden from view, yet changing shape due to the clamp constriction, by, for example, raising the visible wings straight up. In yet other embodiments the clamp may be provided with centering holes or slots so that the marker material is forced partially through it. This configuration may be used to ensure that the marker material becomes equally distributed to the band sides during installation. The marker itself may need to be structured with a ridge, hardness or other likewise features promoting controlled bulging or shape shifting of the marker.
In addition, as the displaceable material of the marker may have different physical properties, there may be also differences in ability of the displaceable material to indicate installation issues. Flexible materials with shape memory, like rubber, may be able to return into the initial position between the clamp and the object after un-loading the clamp. An irreversible marker material, on the other hand, retains its last enforced shape. One or another type of marker material may be useful, depending on requirements and circumstances of a particular band clamp installation.
There may be a geometric aspect of the invention so as to have an installation marker made of resilient material to conform to the system of forces created by a tightened band clamp together with all intervening parts so as to achieve proper band clamp joint tightness. This calls for a marker with purposefully designed shape and structure, for example thinned at the end or sickle-like. Analytical and experimental tools can be used to achieve the right combination of shape and strength.
Reinforcement layers to guide and protect the marker material during deformation may be optionally used with the marker. Such reinforcement may be integral to the marker or separate until finally assembled. Above the marker, as the clamp may be much harder than the marker, the clamp band edges can forcefully cut the dislocated marker material. This calls for reinforcement at the top surface of the marker where it meets the relatively sharp clamp edges. On the underside, irreversible marker material may have tendency to raise uncontrollably up and detach itself from the clamped object. To prevent this phenomenon from happening a guiding reinforcement layer of material may be needed at the inner face of the marker. The reinforcement layers of material should typically be stretchable so as to not limit deformation of the marker material. The materials at the friction boundaries, like the one between the marker and the clamp, may have also a purposefully lowered friction coefficient, for example by using low friction materials like fiberglass and/or special lubricants. This may ease controlled deformation and dislocation of the marker materials during installation. Specifically regarding reinforcement layers external to the marker, they may initially extend sidewise slightly beyond the clamp edges to both decrease friction and ensure protection of the marker from cutting. The sidewise width of such reinforcement may be limited however, so as not to diminish visibility of the marker. Examples of stretchable materials suitable for reinforcement include, but are not limited to loosely woven fiberglass cloth or sinusoidally woven fiberglass cloth. For example, a rotated 45 degrees length of squarely woven fiberglass cloth may be useful, providing stretchability and decreased friction coefficient. Metal cloth may be also used.
In some embodiments, the sides of the marker may be allowed to raise up (flag), rather than bulge on the sides of the band clamp band as the band clamp is tightened. This may occur, for example, when the marker material is placed transversally respective to the clamp loop as opposed to it being placed longitudinally hidden under the band.
Referring now to FIGS. 1 through 4 , a band clamp 10 may comprise a bolt 12 for tightening the band clamp 10 around a sleeve 14 and a center tube 16 , for example. The band clamp 10 of the present invention may be tightenable by different connector types used in various environments, similar to those where conventional band clamps may be used.
Under a portion of the band clamp 10 there may be disposed a flexible marker material 18 . The displaceable marker material 18 may be a thixotropic material, such as a clay, for example, or may be a gel, paste, rubber, micro-cell rubber or the like. Some materials, like rubber, may have shape memory, others may be displaceable only in an irreversible manner. In some embodiments, the marker material 18 may be formed by layering a silicone self-fusing tape, such as MOX-Tape®, or combining the tape with other materials. The tapes may be of various thicknesses as well as may have built-in stretchable sinusoidally woven reinforcement. In other embodiments the marker may be formed in one piece in an optimized shape.
As shown by looking at FIGS. 2 and 3 , when the band clamp 10 becomes tighter, the marker material 18 is forced to bulge and then part sidewise finally leaving under the clamp only a residual amount of displaceable substance plus stretched reinforcement 20 . The marker material 18 may stick to the reinforcement layer 20 , ensuring that the marker material 18 does not raise up due to bulging of a flexible object underneath. This way, bulges of displaced marker material 18 are created as seen in FIG. 2 . A typical material displacement mode is symmetrically to both sides of the clamp 10 , but the material can be also guided to only one side.
A reinforcement and/or guiding material 20 may be disposed on an inside side of the marker material 18 , as shown in FIG. 2 . A contrast patch of material 22 may be also disposed between the marker 18 , with or without reinforcement 20 , and the object being clamped. Another band like object like for example a containment bracket (shown in FIG. 5 ) may be disposed between the reinforcement 20 and contrast patch 22 . In such case the reinforcement material 20 may help protect the marker material 18 from cutting damage by the containment bracket when it is pressed against the sleeve 14 . The reinforcement material 20 may be a stretchable flexible material, such as, for example, a rubber tape or loosely woven cloth strip. The reinforcement material 20 may be attached to the marker material 18 by conventional means or, in some embodiments, the reinforcement material 20 may be formed integrally with the marker material 18 . In other embodiments, the reinforcement material 20 may be applied to the sleeve 14 first, then the marker 18 and finally a band clamp 10 . As can be seen, there may be several variations of the clamp characterized by different layering order of intermediate and/or auxiliary parts, such as reinforcement, containment bracket, contrast patch or strip and other add-ons. In one important embodiment the marker and intermediate objects may be integrated into a single marker set.
In FIG. 5 , an embodiment is shown in which a metal containment bracket 40 is designed to encapsulate a marker/reinforcement kit and thus enable it to slide together with the clamp over the surface of the object to be clamped, greatly facilitating installation. The active width of the containment bracket 40 may be approximately equal to the clamp width so as to exert similar forces under load. Another way of pre-attaching the marker 18 to the clamp is by using simple flaps or wings (not shown) that can be folded over the clamp. This and other embodiments decreasing the number of parts to be simultaneously handled during installation may be particularly useful when the band clamp 10 needs to be slid along the tube 16 and sleeve 14 to obtain its proper installation position. For larger joint sizes, the band 10 may be pre-bent as shown in FIG. 5 to more tightly encapsulate the marker.
While FIG. 1 shows the marker material 18 disposed under the bolt 12 near a tightening mechanism 36 , the marker material 18 may be disposed at any location under the band clamp 10 . Typically, the marker material 18 may have a width that is smaller or equal to a width of the band clamp 10 so as to enable hiding it in initial installation position. This way a visible displaced material of the marker may consequently show that the clamp is being properly tightened. In an embodiment with a transversally positioned marker which cannot be quite hidden by the clamp, the visual clues are provided by the visible wings of the marker raising up.
The marker material 18 may have tracking information (not shown) attached or imbedded therewithin. Alternatively the tracking information can be attached to the clamp. The tracking information may help identify an installation date, who installed the band clamp, or other similar data.
The marker material 18 may be, for example, a colored material, typically a brightly colored material. In some embodiments, as shown in FIG. 4 , a color contrast material 22 may be disposed under the marker material 18 . The color contrast material 22 may be wider than the band clamp 10 so that it extends beyond the width of the band clamp 10 . The color contrast material 22 may have a length and width such that it is visible when the band clamp 10 is not tightened. As the band clamp 10 becomes tightened, a masking marker material 18 may be squeezed out from under the band clamp 10 to substantially block the color contrast material 22 from view. For example, in some embodiments, the marker material 18 may be of a neutral color, such as grey or black, and the color contrast material 22 may be bright yellow. This would result in a band clamp 10 in which the contrast patch of color appears to be vanishing during installation.
Referring again to FIG. 5 , in an alternate embodiment of the present invention, a containment bracket 40 may be positioned between the marker material 18 and an object to be clamped. The bracket 40 may be attached to the band clamp 10 to complement an inside circumference of the band clamp 10 . In this embodiment, the band clamp 10 is pre-bent to form a pocket 38 for the marker material 18 . Different pocket geometries may be required to accommodate differently structured markers. Reinforcement material 19 may be applied to the top and/or bottom of the marker material 18 to protect the marker material 18 from being cut by the band clamp 10 on the top side and by the bracket 40 on the bottom side. In some embodiments, the bracket 40 may be pre-attached to the band clamp 10 , along with the marker 18 , to form a ready-to-use band clamp/marker set. The bracket 40 may have special attachment features, such as tabs 42 that permit the bracket 40 to be field-attached to the band clamp 10 .
In some embodiments, the marker material 18 may constitute integral part of the band clamp 10 . In other embodiments, the marker material 18 may be a separate piece or a piece initially attached to a contrast patch 44 , for example a thin aluminum patch with an underlayer of adhesive enabling the marker and contrast patch set to be pre-attached to a clamped object. In the FIG. 6 , the cross-hatched surface represents optional stretchable reinforcement 19 . A similar marker-contrast set may have the adhesive layer at the top, which may be used to pre-attach the set to the clamp. The marker can be also pre-attached to an intermediate long strip of reinforcement material (not shown), which can be looped and affixed directly around a clamped object, over which a band clamp may be then placed and tightened.
A special embodiment is the one in which the contrast patch alone is initially applied to the object to be clamped, not only creating the contrast but at the same time a target-locator patch, indicating the position at which the clamp 10 should be affixed to the clamped object. More than one such target may be applied about the circumference of the clamped object so as avoid potential skewedness of the clamp with respect to the sleeve and tube axes.
Referring again to FIG. 6 , the cross-hatched layer or layers 19 of reinforcing marker material 18 may be stretchable. Stretchability of reinforcement layer 19 is needed for it to be able to forcelessly follow deformation of the marker material 18 . Stretchability may be inherent in material or due to structure of a part. A loosely woven fiberglass mesh may allow deformation while at the same time protecting the marker from being cut by the clamp edges. In some embodiments, the marker material 18 may be applied directly to the sleeve. In turn, to be able to act as a contrast, the layer of material 44 may be wider than the marker material 18 .
Referring to FIG. 7 , the present invention includes a method 24 for properly tightening band clamps. In a step 26 , the band clamp may be applied to an item to be secured. The band clamp may be placed and closed, or closed and placed, then initially adjusted, about the item to be secured. In a step 30 , the band clamp may be tightened until a visually satisfactory portion of an installation marker appears adjacent to edges of the band clamp. Regardless of the embodiment, the marker is ultimately located between the clamp and the clamped object. In some embodiments, the installation marker may be pre-mounted in a pocket formed between a containment bracket and the band clamp band. Optionally, in a step 32 , a color contrast material may be applied between the marker and the item to be secured. In this optional method, in a step 34 , the band clamp may be tightened until all or a desired portion of the color contrast material is visually blocked by the material of the installation marker.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.
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A band clamp has a band constriction sensing marker adapted so as to gradually visibly respond to the stage and state of the band clamp installation at the object to be secured. Before the band clamp is installed, a displaceable material may be partially or entirely hidden between the band and the securable object, for example flexible sleeve, wherefrom it is forcefully moved by the clamp to the sides during installation. A gradually appearing amount, color and shape of the moved marker material may provide visual clues about band clamp installation. In some embodiments, a contrastingly colored under material wider than the band clamp may be disposed underneath a marker on the side of the object being secured. Due to the band constriction during joint installation, the marker material parts sidewise from underneath the band clamp and masks the contrasting under material with neutrally colored marker material.
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BACKGROUND OF THE INVENTION
The present invention relates essentially to a method of and device for remotely detecting leaks or like defects in fluid-tightness in a pipe-line or a like feeder main conveying any fluid whatsoever and submerged within an ambient or surrounding fluid as well as to a pipe-line or duct provided with such a detection device.
More particularly the invention is applicable to the remote detection of leaks or like defects in fluid-tightness of an underwater pipe-line or like submarine duct for carrying a fluid such as a liquefied gas or the like between a land location on shore of a coastal area and an off-shore location far away in the sea for the loading and/or unloading of a ship such as, for example, a tanker ship.
Submarine fluid-carrying or feeder pipe-lines for enabling a ship to be unloaded and/or loaded at a location substantially far away from the shore are already known. In case of a leak or like defect in fluid-tightness in such a feeder pipe-line, resulting in leaks of one of the conveyed or ambient fluids towards the other, it is not known how to continuously and remotely detect such leaks and moreover after having ascertained the existence of a leak on a length of the pipe-line it is not known how to accurately locate it without any manual inspection of the whole length of the pipe-line.
According to the known state of prior art indeed when it was found that a pipe-line exhibited a leak or like defect in fluid-tightness thereof it was then necessary to send an operator for inspecting the whole length of the pipe-line with a view to detecting such a defect in fluid-tightness and the leak of one of the fluids. It is therefore obvious that such an inspection of the pipe-line taking place in a medium or environment relatively hostile to man, namely deep within the sea, was very difficult to be carried out and required much time and a significant infrastructure. On the other hand, as the fluid-conveying submarine pipe-lines are generally lined or covered with a coating or sheath of concrete the operator was often compelled to damage such a protective layer in order to detect and locate the leak or leaks of one of the fluids.
SUMMARY OF THE INVENTION
The object of the present invention is to solve all these problems by providing an approach which makes it possible to remotely detect and locate continuously the defects in fluid-tightness or leaks of such a transmission pipe-line.
The approach is according to the present invention a particular self-acting method for automatically detecting defects in fluid-tightness or leaks of a fluid-confining or holding enclosure, which consists, for a pipe-line carrying any fluid whatsoever and submerged within an ambient fluid, in remotely detecting a leak of one of the fluids towards the other one. The method comprises at least two preferably substantially simultaneous or concomitant respective steps of local leak detection and overall leak detection performed on the whole pipe-line.
Thus according to the process of detecting defects in fluid-tightness or leaks according to the invention it is possible to quickly detect a leak occurring in the whole length of the pipe-line through an overall detection and to locate such a leak by means of a local detection. Furthermore such a double leak detection makes it possible to remove any risk of mistake due to an abnormal operation of one of these overall or local detections.
According to another characterizing feature of the invention said overall detection step consists in constantly surrounding the pipe-line with a confined layer of an auxiliary sweeping fluid interposed between said pipe-line and the ambient or surrounding fluid, said auxiliary fluid being at a pressure lower than the respective pressures of the conveyed fluid and of the ambient fluid and being constantly kept flowing throughout the whole length of said pipe-line. This overall detection step consists also in detecting the presence of at least one of the conveyed or ambient fluids, respectively, within said auxiliary fluid by means of a continuous watch on or control of the composition of the flow of auxiliary fluid issuing from an accessible end of the pipe-line.
According to still another characterizing feature of the invention, said auxiliary fluid is a simple possibly inert gas or a mixture of gases at least the main component of which is possibly an inert gas and preferably nitrogen.
Thus according to the invention an analysis of the stream of auxiliary fluid exiting from an accessible end of the pipe-line may be easily carried out for detecting the presence of the ambient or conveyed fluid within said auxiliary fluid without it being necessary to move around within the environment or ambient medium.
According to a further characterizing feature of the invention, the process is applicable to a pipe-line embedded in a layer of solid material surrounded by the auxiliary fluid wherein any leak of the conveyed fluid is channelled or guided generally in a circumferential direction along the wall of said pipe-line so as to store said fluid within a continuous and relatively reduced volume or space extending along said pipe-line and wherein the stored leak is at least partially transferred to said auxiliary fluid.
According to still another characterizing feature of the invention, the method consists in performing the transfer of the collected or gathered leaking conveyed fluid towards the layer of auxiliary fluid when the pressure of the stored leaking conveyed fluid reaches a determined value.
According to another characterizing feature of the present invention the step of locally detecting the leak of the conveyed fluid consists in confining the gathered leak of conveyed fluid by dividing the storage voltage or space into adjacent sections isolated in sealing relationship from each other, in detecting the presence of the conveyed fluid within each aforesaid section and in case of presence of said conveyed fluid in emitting a signal for giving an alarm or operating a warning device. The signal, which corresponds to the presence of leaking conveyed fluid within at least one of the sections, is advantageously emitted when the pressure of the fluid carried within said section reaches a determined value.
According to a further characterizing feature of the invention, the local detection of the presence of the ambient or surrounding fluid within said auxiliary fluid consists in detecting at points statistically distributed over the length of the pipe-line and corresponding substantially to the local low points of said pipe-line the presence of ambient fluid and in emitting a signal in case of detection to give an alarm or operate a warning device.
A signal is advantageously emitted when the level of the ambient fluid locally stored within the space for confining said auxiliary fluid reaches a determined value.
The present invention is also directed to a pipe-line for conveying or feeding any fluid whatsoever and submerged within a fluid environment or ambient medium, which according to the invention, comprises local detection means and overall detection means for detecting a leak of one of the fluids towards the other one.
The pipe-line or duct according to the invention comprises an inner in particular metallic conveying tube surrounded by an outer preferably metallic tube radially spaced from the inner tube and defining a continuous annular space therebetween throughout the length of the pipe-line. According to the invention, the means for overall detection of a leak of one of the fluids towards the other one comprise said annular space, means for sweeping or scavenging said annular space with an auxiliary fluid, means for analysing the composition of the exiting flux of said auxiliary fluid at an accessible end of said pipe-line and alarm or warning means connected to said analysing means.
According to a preferred embodiment of the invention, the pipe-line is of the kind comprising an externally heat-insulated or lagged conveying tube and a preferably impervious shell, casing, sheath or like envelope of small thickness surrounding the heat-insulation or lagging in contacting relationship therewith and it comprises according to the invention, interposed between said conveying tube and the heat-insulation or lagging, a device for channelling or guiding or directing the leaks of the conveyed fluid and a device for collecting said guided or channelled leaks communicating with the guiding device. According to the invention, the collecting device has advantageously a reduced cross-section extending over the whole length of the tube and is provided with at least one member for putting it into communication with said annular space surrounding said heat-insulated tube. This member is according to a preferred embodiment of the invention a valve opened automatically by the pressure prevailing within said collecting device.
According to another characterizing feature of the invention, said channelling or guiding device consists of at least one layer of fabric or cloth resistant to the conveyed fluid and wrapped or wound continuously about the conveying tube. According to the invention, this fabric is advantageously a glass fiber fabric with free loops and with a taffeta weave.
Moreover, said collecting device is according to the invention a substantially trough-shaped duct secured onto said fabric and filled with a porous material such as for instance a polyurethane foam with burst cells or the like. The envelope, shell or casing defining said collecting device is made from a plastics material withstanding pressure so as to avoid any straining or deformation of said collecting device during the building or manufacture of the pipe-line.
The pipe-line according to the invention is moreover characterized in that said collecting device is divided into longitudinally successive adjacent sections isolated in sealing relationship from each other and there is provided means for locally detecting any leak of the conveyed fluid, comprising said sections and at least one detector arranged on each aforesaid independent section, said detector being connected to alarm or warning means and advantageously being according to the invention a pressostat or like pressure controller.
The division of said collecting device according to the invention into independent sections of reduced lengths with respect to the overall length of the pipe-line makes possible an accurate remote location of the leaks of the conveyed fluid and accordingly that detection enables an operator to effect a quick pinpoint intervention on the stop for coping with or stopping said leak of the conveyed fluid.
The pipe-line according to the invention is moreover characterized in that the means for locally detecting any leak of the ambient fluid comprise detectors for sensing the presence of ambient fluid within the annular space, which are arranged within said annular space while being distributed throughout the length of the pipe-line at positions corresponding substantially to the local low points of said pipe line, said detectors being connected to alarm or warning means.
According to the invention, these detectors for sensing the presence of fluid are advantageously detectors sensing the level of the ambient fluid locally gathered within the annular space, said detectors emitting a signal transmitted to the alarm means when the local level of the accumulated ambient fluid reaches a determined value.
The fluid-conveying pipe-line, submerged within an ambient or surrounding fluid such as in particular a submarine pipe-line for carrying a liquefied gas, as provided by the invention, makes it possible to detect and to locate remotely in a reliable manner the defects in fluid tightness or leaks of the pipe-line owing to the dual device for detecting such defects or failures.
Moreover, in case of a leak of little significance of one of the conveyed or ambient fluids towards the other one, it is possible according to the invention to stop such a leak by building up an overpressure within the annular space interposed between the ambient fluid and the conveyed fluid without requiring any human intervention on the portion of submerged pipe-line.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention reference is had to the following description, taken in connection with the accompanying drawings, in which:
FIG. 1 is a general diagrammatic layout illustrating the positioning of a fluid-conveying pipe-line according to the invention on a sea bed or bottom;
FIG. 2 is a cross-sectional view, on an enlarged scale, taken along the lines II--II, of FIG. 1 and illustrating an embodiment of the pipe-line according to the invention;
FIG. 3 is an axial-sectional view, taken along the lines III--III of FIG. 2 and showing in particular the structure of the pipe-line according to the invention at the connection of two pipe or duct elements and at the junction of two independent adjacent sections of the device for collecting the leaks of the conveyed fluid;
FIG. 4 is an axial-sectional view, on an enlarged scale, through the part IV of FIG. 1, showing a first preferred embodiment of the means for discharging or removing the ambient fluid according to the invention;
FIG. 5 is a view similar to FIG. 4 and showing a second preferred embodiment of the ambient fluid removing or discharging means according to the invention;
FIG. 6 is a block diagram illustrating the arrangement for remotely detecting the defects in fluid-tightness of a fluid-conveying pipe-line according to the principle of the invention; and
FIGS. 7 and 8 are process or data flow charts respectively illustrating the various stages of remotely detecting a leak of the conveyed fluid and a leak of the ambient fluid according to the principle of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
With reference to the accompanying drawings and more particularly to FIGS. 1, 2, 3, 4 and 5 the construction of a fluid-carrying pipe-line 1 submerged within an ambient fluid according to the invention and comprising means for remote local detection and remote overall detection of defects in fluid-tightness of said pipe-line will now be described.
Referring to the drawings, FIG. 1 shows the positioning of a submarine duct or pipe-line 1 carrying a fluid such for instance as a liquefied petroleum gas onto the sea bed or bottom Q between a point located off-shore or far away at sea (not shown) for unloading and/or loading a cargo ship and a point on land or ashore P of a coastal area. As a general rule and as partially shown in FIG. 1, a submarine pipe-line 1 rests on the sea bottom Q while exhibiting a wavy shape or undulations of small amplitude and it therefore exhibits throughout its length high points P H and low points P B . By way of exemplary illustration for an underwater pipe-line of a length of 3,500 m the amplitude of the waves or undulations is about 2 m on an average and the frequency or pitch thereof is about 150 m.
With reference to FIG. 2, the fluid-conveying duct 1 according to a preferred embodiment of the invention comprises an inner metallic pipe or tube 2 for carrying liquefied petroleum gas. The conveying tube 2 is embedded into a layer 4 of a material exhibiting suitable qualities of heat-insulation and mechanical strength for lagging or heat-insulating the conveying tube or pipe 2. By way of example, there may be used polyurethane injected as a dense or compact foam. Moreover said layer 4 of heat-insulating material is surrounded by an impervious envelope or sheath 5 of small thickness. This impervious sheath consists of steel sheets or foils wrapped or wound spirally with preferably overlapping turns and welding thereof together whereas for tubes or pipes of smaller diameters the sheath is made from a plastic material such as polyethylene, for example.
As shown in FIG. 2, it is advantageous to provide centering pads or studs 6 about said conveying tubes 2 so that said impervious sheath or casing 5 may be easily wrapped or wound around and the heat-insulating material may be injected within the space defined between the tube 2 and the impervious sheath 5.
According to a significant feature of the invention, the conveying tube 2 is covered externally by at least one fabric layer 3 in contacting relationship therewith which is spirally wrapped or wound thereabout preferably with the turns 3a thereof partially overlapping each other (FIG. 3). According to the invention, it is advantageous to adhesively bond or stick the fabric layers 3 onto the outer wall of the conveying tube 2 by means of a thin layer of resin, for example, a layer of epoxy resin.
According to the invention, it is advantageous that the fabric layer 3 be made from a strip of preferably silicon-coated glass fiber fabric with free or exposed loops and taffeta weave. The free or exposed loops of the glass fiber fabric provide indeed for a greatly improved adhesion or bonding of the lagging 4 onto the surface of said fabric. Moreover, the taffeta weave allows a better drainage of the possible leaks of the conveyed fluid.
According to the invention, the duct 1 also comprises throughout its length a collecting or draining device 7 for gathering the leaks of the conveyed fluid which are conducted or guided by the glass fiber layer 3. This collecting device consists of a casing or channel 8 having its free edges formed with fastening lugs, tongues or like flanges 8a for adhesively bonding or sticking same onto the glass fiber layer preferably at the lower portion of the tube 2 and along a longitudinal generating line of said duct.
According to the invention, the draining means 7, is advantageously filled with a porous material 9 such as, for example, a polyurethane foam with burst or open cells.
Furthermore, the casing or channel-like envelope 8 of the draining means should be made from a material capable of withstanding pressure, for example, from a plastics material so as to prevent same from being strained or deformed during the setting or polymerization of the heat-insulating material 4 injected into the space defined between the glass fiber fabric layer 3 and the impervious sheath 5.
According to the invention the fluid conveying pipe-line or duct also comprises an outer metallic shell or envelope 10 or like external tube so as to define an annular space 11 between said outer tube 10 and the impervious sheath or shell 5.
For the purpose of properly and readily positioning the assembly or system consisting of the conveying tube 2, the glass fiber fabric layer 3, the lagging 4 and the impervious sheath 5 and referred hereinafter as duct element 17, positioning members or sprags, pads or like blocks 12 are arranged on the outer surface of said duct elements and the outer tube 10 is positioned about said sprags or pads. It is advantageous to provide on the surface 12a of contact of the pads or sprags 12 with the outer tube 10 a film or thin layer of material 13 having a small coefficient of friction so as to facilitate the relative motions between the duct element 17 and said outer tube 10.
It should be pointed out that without departing from the gist of the invention the duct element 17 and the outer tube 10 may be concentric or eccentric with respect to each other so as to increase the width of the annular space 11 at any place of the pipe-line and preferably at its lower portion.
Moreover, the pipe-line 1 comprises as known per se an outer guard or protective layer 14 consisting of a concrete coating. This concrete coating is also used as a ballasting weight for the pipe-line 1 so as to keep it laying on the sea bottom Q.
According to the invention the pipe-line 1 comprises at least two ducts arranged within the annular space 11. According to the embodiment shown on FIG. 2, the duct 16 which extends throughout the length of the pipe-line is a duct for carrying the flow of auxiliary fluid used for sweeping or scavenging the annular space 11. The duct 15 preferably located at the lowermost portion of the pipe-line constitutes the device for removing or discharging the ambient fluid possibly accumulated or gathered within said annular space. This discharging device will be described hereinafter in greater detail.
The method of building a pipe-line according to the invention will now be described with reference to FIGS. 2 and 3.
It is obvious that the whole length of the pipe-line is made on a building site on land by welding end-to-end several duct elements 17 and several sections of outer tube 10 as shown in FIG. 3. FIG. 3 indeed shows a portion of the pipe-line 1 according to the invention including a first duct element 17a and the end parts of two duct elements 17b, 17c welded to the respective ends of the duct element 17a, and likewise sections of outer tube 10a, 10c and 10b for making the outer envelope 10 of the pipe-line. FIG. 3 also shows the arrangement of the pads 12 along said pipe-line.
The construction of a duct element such as, for example, the duct element 17a will now be described with reference to FIG. 3. This duct element 17a comprises a central portion and two short portions at each end thereof. As shown in FIG. 3, the central portion of this duct element has the same structure as the structure shown in FIG. 2 and defined previously. It is however preferable that the drain 7a slightly extend beyond or project from each end of said central portion. Both end parts of the element 17a consist of a portion of the metal tube 2a. It is therefore easy to weld together both end parts of both adjacent duct elements, for example, the end parts of the duct element 17a and the duct element 17c so as to make the conveying tube 2.
In order to provide a pipe-line structure which is substantially continuous throughout its length the ends of each duct element 17a, 17c are covered with a connecting member 18.
As shown in FIG. 3, the connecting member 18 comprises a layer of glass fiber fabric 3d adhesively bonded or stuck onto the end portions of the ducts 17a and 17c for carrying out the junction between the glass fiber fabric layers 3a and 3c, respectively, of the duct elements 17a, 17c. Onto said glass fiber fabric layer 3d is adhesively bonded or glued a drain element 7d so as to connect the drain means 7a of the duct element 17a to the drain means 7c of the duct element 17c. About the assembly is then laid a layer of heat-insulating material 4d consisting of two half-shells or cups tightly clamped together by means of an outer envelope or sleeve 9 preferably consisting of a heat-retractable material. The layer of lagging 4d may also be made like the layer 4a by injecting a polyurethane foam between the fabric layer 3d and an outer metal envelope (not shown in the Figures).
Moreover, in order to complete fluid-tightness the sleeves 20 of small widths are adhesively bonded or stuck about the line of junction between the adjacent layers of lagging 4a, 4d and 4c. These sleeves may be made either from a thin metal sheet or foil or from a sheet of plastics material.
The sections of outer tube 10a, 10b and 10c are welded end-to-end so as to form the outer tube 10 of the pipe-line 1.
Furthermore, there is provided an expansion joint (not shown in the Figures) mounted onto the inner steel tube 2 and distributed over the whole length of the pipe-line according to the principle described for instance in the applicant's French patent specification publication No. 2,362,330.
According to a particular feature of the invention and as diagrammatically shown in FIG. 1, the composite structure consisting of the layer 4 of lagging and the drain 7 is divided into adjacent longitudinally successive sections 1a to 1x isolated in fluid-tight relationship from each other. According to the preferred embodiment of the invention these sections comprise several duct elements 17a, 17c, . . . and consist, for example, of six duct elements forming a duct length of about 72 m.
FIG. 3 shows the separation between two adjacent sections such, for example, as 1a and 1b. This separation according to a preferred embodiment of the invention is achieved by securing or fastening a closure sleeve 21 onto one of the ends of the drain 7a and of the lagging 4a of the end duct element 17a of the section 1a.
As shown in FIG. 3, the end of the section 1b consists of a duct element 17b devoid of any closure sleeve 21. The other end of the section 1a (not shown in the Figures) is like the end of the section 1b shown in FIG. 3 and similarly the other end of section 1b (not shown in the Figures) is like the end of the section 1a depicted in FIG. 3.
Moreover, each independent section 1a, 1b, 1c, . . . , 1x comprises a duct element 17a onto which has been mounted an automatically opening valve 22 for providing communication between the drain 7 of the section 1a and the annular space 11. The opening of the valve is controlled or operated by the pressure prevailing within the drain 7 of the section 1a. It is advantageous to adjust the valve opening for a pressure low enough to prevent the lagging 4 from coming unstuck or separating from the inner conveying tube 2.
Moreover, each independent section 1a, 1b, 1c, . . . , 1x comprises a duct element as illustrated in FIG. 3, i.e. the duct element 17b onto which is secured a detector 23 or so-called pressostat or pressure controller sensing any increase in pressure. This detector senses any pressure increase within the drain 7 of the corresponding section, i.e. the section 1b in FIG. 3.
It is obvious that without departing from the scope of the invention, every independent section may comprise several valves 22 and/or several pressure controllers or pressostats 23. Furthermore, the pressostats or pressure controllers 23 and valves 22 may be positioned anywhere along the length of the independent section involved. According to a preferred embodiment of the invention, it is however advantageous to arrange a pressostat or pressure controller 23 near one end of a section and a valve 22 near the other end of said section.
According to another particular feature of the invention and with reference to FIGS. 3, 4 and 5, level detectors 24 are mounted on the impervious envelope 5. According to an embodiment of the invention, these level detectors such as, for example, contact-making or switching floats are statistically distributed over the whole length of the pipe-line so as to be located at the probable low points P B (FIG. 1) of the pipe-line.
It is of course obvious that connecting cables or wire leads connect the different level detectors 24 and the different pressostats or pressure controllers 23 to a signal receiver or alarm or warning means.
Both preferred embodiments of the means for removing or discharging the ambient fluid possibly accumulated within the annular space 11 will now be described with reference to FIGS. 4 and 5. According to a first embodiment shown in FIG. 4 and in FIG. 2, these discharge means consist of a tube 15 arranged at the lowermost portion of the annular space 11. This tube extends throughout the length of the pipe-line and provides for the removal through pumping or the like of the gathered ambient fluid. This discharge tube is provided with plungers or valves 25, the opening of which is remote-controlled by a self-acting device such as, for example, a heat controlling device or so-called calorstat or a hydraulic servo-valve device. In a manner similar to the level detector 24 such drain traps or units are statistically distributed throughout the length of the discharge tube 15 so that they be positioned substantially at a low point P B (FIG. 1) of the pipe-line 1.
According to a second embodiment shown on FIG. 5, the means for removing or discharging the ambient fluid possibly stored within the annular space 11 consist of several syphon tubes 15a, 15b, 15c, . . . of small diameters. These syphon tubes are arranged in the lowermost part of the annular space 11 and each syphon tube connects two successive low points P B of the pipe-line 1. As shown in FIG. 5, the outlet of a syphon tube 15a is located downstream of the inlet of the following or next syphon tube 15b.
After these different elements have been assembled and mounted at a working site on land, said pipe-line 1 is embedded in a protective concrete layer 14 and the pipe-line 1 is submerged into the environment or surrounding medium according to a well-known process.
The means of overall detection and local detection of the defects in fluid-tightness of the pipe-line 1 according to the invention will now be described more particularly with reference to FIG. 6. In this Figure, the thick or heavy connecting lines represent the circuit of auxiliary fluid and the thin or fine connecting lines represent either the alarm signal transmission connections or the control signal transmission connections.
According to the invention, the overall detection of defects in fluid-tightness of the pipe-line 1 consists in sweeping or scavenging the annular space 11 with an auxiliary fluid a major part of which consists of nitrogen.
According to a preferred embodiment of the invention, a system for overall detection of defects in fluid-tightness comprises a source of auxiliary fluid 26 consisting either of a supply of gas or of a nitrogen-generating air distillating apparatus. The source of auxiliary fluid 26 is connected to a feeding device 27 consisting advantageously of a pump or compressor for feeding the auxiliary fluid into the annular space 11 with a variable flow rate and under an adjustable pressure. The stream of auxiliary fluid will issue from the pipe-line 1 through the agency of a flow duct 16 extending throughout the length of the pipe-line and having an outlet at the accessible end of said pipe-line near the point P (FIG. 1). The flow duct 16 is connected to means 28 for analysing and controlling the composition of the exiting flux of auxiliary fluid. In the case of a submarine pipe-line carrying liquefied petroleum gas such analysing means consist advantageously of an infra-red-radiation spectrometer for detecting traces of moisture within the auxiliary gas and of an explodimeter for determining in terms of percentage the lower limit of explodability of the conveyed fluid possibly contained within the auxiliary fluid. Then the flux of auxiliary gas may be either re-cycled into the sweeping circuit or removed by means of a selector valve 29 according to whether the detection by the analysing means 28 is negative or positive, respectively.
It should be understood that the analysing means 28 described hereinabove are given by way of exemplary illustration only and may be substituted for by any equivalent analysing means without departing from the gist of the invention.
Moreover, the analysing means 28 are connected to an alarm or warning system 30 for triggering or starting a control device 31 with a view to operating the selector valve 29 in particular.
According to a preferred embodiment of the invention, the local detection of defects in fluid-tightness of the pipe-line 1 comprise at first an ambient fluid level detector 24 mounted within said annular space 11. These level detectors 24 transmit a signal in case of local accumulation of ambient fluid within the annular space 11 to the alarm or warning device 30 connected to the control device 31 for actuating the ambient fluid removal means. Such fluid discharge or draining means consist either of the draining duct 15 and drain cocks or units 25, the syphon tubes 15a, 15b, or a suction means (not shown in the Figures) for drawing the ambient fluid.
The means for local detection of defects in fluid tightness according to the invention also comprise pressure controllers or so-called pressostats 23 mounted in each section 1a, 1b, 1c, . . . , 1x of the pipe-line 1. In a manner similar to the level detectors, these pressure controllers or so-called pressostats 23 feed a signal to the alarm or warning device in case of a leak of the conveyed fluid.
The process of remotely detecting defects in fluid-tightness of the pipe-line 1 according to the invention will now be described with reference in particular to FIGS. 7 and 8.
There will be described at first with reference more particularly to FIG. 7, the operation of the remote detection of defects in fluid-tightness of the inner conveying tube 2 or in other words of the leaks of the conveyed fluid.
As previously described, the conveying tube 2 is preferably heat-insulated with epoxy resin having closed cells hence of dense or compact character. According to the invention, the leaking conveyed fluid follows the path of travel of least resistance offered by the glass fiber fabric layer 3. In view of the pressure of conveyed fluid and of its weight, the latter fluid will collect and accumulate within the corresponding drain section 7. The glass fiber fabric by guiding or conducting the leaks of the conveyed fluid into the drain avoids an increase in the pressure between the conveying tube 2 and the lagging 4 at any point of the pipe-line; such an increase in pressure could possibly cause said heat-insulating layer 4 to come unstuck or detached and to be damaged.
The accumulation of the leaking conveyed fluid within the drain section 7, for example, in the drain 7a corresponding to the section 1a of the pipe-line, induces an increase in pressure within said drain section. Therefore the valve 22 is opened by that pressure and enables the leaking conveyed fluid to escape into the annular space 11. The valve 22 is advantageously set or adjusted to a pressure low enough to prevent the highest pressure prevailing within the drain 7 from causing the insulation layer to come unstuck or be separated from the inner tube 2, the set pressure being, for example, about 2 bars.
Accordingly, when the pressure of the leaking conveyed fluid accumulated within a drain section 7 reaches a certain value the fluid would move out and pollute the auxiliary fluid sweeping or scavenging the annular space 11 and on the other hand the pressure controller or pressostat 23 of said drain section would emit a signal conveyed to the alarm means 30.
FIG. 7 shows the flow chart or block diagram of the leak detection for the conveyed fluid. This detection consists in a continuous analysis A of the exiting flux of auxiliary fluid so as to sense or trace the presence of conveyed fluid therein, for example, in the case of propane or butane or the like, in the determination in terms of percentage of the lower limit of explodability and in a continuous watch or monitoring B of the pressostats or pressure controllers 23 mounted on each independent drain section 1a, 1b, . . . , 1x. When the result of the analysis C of the exiting flux of auxiliary fluid is positive, for example, if the percentage of the lower limit of explodability reaches a certain threshold (about 30%) and when at least one of the pressure controllers or pressostats 23 emits a signal D, the existence of a leak of conveyed fluid in the inner tube 2 is detected with certainty (stage E). Moreover, the localization of the signal-emitting pressostat or pressure controller permits the location of the independent duct section 1a, 1b, 1c, . . . , 1x exhibiting a defect in fluid tightness.
The stage F is then started, which consists in increasing the auxiliary fluid sweeping flow rate to a value higher than 10 N m 3 /h for removing or discharging the leaking conveyed fluid present in the annular space 11. During that step of removing the leaking conveyed fluid the auxiliary fluid is of course not re-cycled and is rejected to the atmosphere through a degassing mast or the like, for example.
In the case of a negative analysis A of the exiting flux of auxiliary fluid, the sweeping flow rate of auxiliary fluid is kept to a value of about 1 N m 2 /h.
In the case of a negative analysis of the exiting flux of auxiliary fluid and of the emission of a signal by at least one of the pressure controllers or pressostats 23, the warning system showing the presence of a leak of conveyed fluid is not actuated but the operations of said pressostats or pressure controllers are controlled.
Thus the method of remotely detecting leaks of conveyed fluid within a pipe-line according to the invention makes it possible due to both simultaneous or concomitant local and overall leak detections, respectively, to determine and to locate with certainty the presence of a leak of conveyed fluid and only in that case to take action on the pipe-line for removing the defect in fluid-tightness thus detected.
It is of course obvious that the analysing means are adapted to the nature of the conveyed fluid and that the means of local detection comprise all the means providing the local detection of a fluid within a restricted volume or space.
The method of detecting a defect in fluid-tightness of the outer envelope of the pipe-line, i.e. the leaks of ambient fluid will now be described with reference to the flow chart or block diagram of FIG. 8.
In case of a defect in fluid-tightness of the envelope consisting of the tube 10 and the concrete 14, the ambient fluid would flow into the annular space 11 and accumulate at the low point P B of the pipe-line (shown in FIG. 1). According to the invention the presence of ambient fluid in that annular space 11 is continuously detected by the analysis of the exiting flux of auxiliary fluid and when the amount of accumulated ambient fluid reaches a certain level, the local level detectors 24 would emit a signal transmitted to the alarm means 30. Therefore the method of detecting a defect in fluid-tightness of the outer envelope of the pipe-line 11 is based on a dual simultaneous or concomitant overall and local detection, respectively, of the presence of ambient fluid within the annular space 11.
FIG. 8 illustrates the flow chart or block diagram of the detection of a leak of the ambient fluid. That detection comprises the continuous analysis A 1 of the exiting flux of auxiliary fluid through the determination of the presence of ambient fluid within the auxiliary fluid, for example, in the case of a submarine pipe-line, the analysis of the traces of moisture and the continuous watch or monitoring G of the level detectors 24 distributed over the whole length of the pipe-line, for example, about every 100 m.
In the case of negative responses C 1 , H of the detection steps A 1 , G, the outer envelope of the pipe-line does not exhibit any defect in fluid-tightness.
If there is a positive response from the analysis A 1 of the auxiliary fluid and the emission of a signal by at least one level detector 24, the existence of a defect in fluid-tightness of the outer envelope of the pipe-line and the accumulation of ambient fluid at a low point of the pipe-line, which is located by the position of the signal-emitting detector, are then detected with certainty. In such a case the process stage I is then performed, which consists in pressurizing the annular space to a value higher than the pressure of the ambient fluid to prevent any further ingress of ambient fluid into the annular space. It should be noted that this pressurization should be carried out along the whole length of the pipe-line.
In the case of maintaining the pressure J the water is removed from the annular space 11 by the discharge means arranged within the pipe-line and this stage is illustrated by the reference character K on FIG. 8. This water-removal stage is carried out according to a first preferred embodiment of the invention by opening the drain cocks 25 arranged on the discharge duct 15 which are operated automatically or by hand by the control means 31 (FIG. 6). According to a second preferred embodiment of the invention the removal of ambient fluid is effected through the syphon tubes 15a, 15b connected to a suction device (not shown in the Figures).
If the pressure within the annular space is not maintained the repair L of the outer envelope of the pipe-line is carried out.
According to the invention, when the analysis A 1 of the auxiliary sweeping fluid yields a positive response C 1 and if no signal is detected by the watch or monitoring G of the level detector 24, it is advantageous to pressurize the annular space 11 to a pressure higher than the pressure of the ambient fluid in order to prevent any further ingress of ambient fluid into said annular space. In such a case indeed the leak of ambient fluid is small and may be easily stopped through an increase in pressure within the annular space. Moreover, it is preferable to increase the flow rate of said auxiliary fluid to carry along and remove the ambient fluid.
If the pressure N is not maintained it is then necessary to proceed with the stage L of repairing the outer envelope.
The method of and the device for detecting the defects in fluid tightness of the outer envelope of a fluid-conveying pipe-line as provided by the invention therefore permits certain detection of the presence of one or several defects in fluid-tightness of said outer envelope by the dual simultaneous detection of the presence of ambient fluid within the annular space 11.
Another significant advantage of the method and device of the invention resides in the fact that even in case of the existence of a defect in fluid-tightness of the outer envelope of the pipe-line the transfer of conveyed fluid towards or from the point P through merely pressurizing the annular space may be continued. Such a pressurizing indeed stops the ingress of the ambient fluid into the annular space and permits waiting for the end of the conveyed fluid transfer step for carrying out the repair of the outer envelope.
It should be understood as previously described that the detection of defects in fluid-tightness of the conveying tube 2 and the detection of defects in fluid-tightness of the outer envelope are performed at the same time through a continuous watch on or monitoring of the level detectors 24 and pressure controllers or pressostats 23 and through a double analysis of the exiting flux of auxiliary fluid to detect the presence of ambient fluid and of the conveyed fluid therein.
The present invention accordingly provides a fluid-carrying pipe-line in particular a submarine pipe-line for conveying liquefied petroleum gas, comprising a device for detecting defects in fluid-tightness of the conveying tube 2 proper and of the outer envelope of said pipe-line.
Therefore, the invention makes it possible to reliably and dependably determine the necessity of a manual intervention for repairing the pipe-line and also permits the location of such an intervention along the length of the pipe-line. This is very important when access to the pipe-line is difficult due to its submersion within an ambient fluid hostile to humans.
It should be understood that the invention is not at all limited to the embodiments described and shown herein which have been given by way of examples only. Thus, the nature of the insulating material, the nature of the ballasting weight may be of any kind without departing from the scope of the invention. This means that the invention comprises all the means constituting technical equivalents of the means described as well as their combinations if same are carried out according to its gist and used within the scope of protection claimed.
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A pipe-line for conveying a fluid submerged in an ambient fluid medium has an inner conveying tube surrounded by an outer tube radially spaced from the inner tube and defining a continuous annular space therebetween. A leak conductor communicating with a leak collector and surrounding the inner conveying tube conducts leaks of conveyed fluid to the leak collector. The leak collector has a reduced cross-section and is divided into adjacent sections isolated in a fluid-tight manner relative to each other and extending throughout the length of the tube. Each of the sections has at least a single valve automatically opened by predetermined pressure of the conveyed fluid leaks for providing communication with the annular space surrounding the inner tube. A leak detecting system in the annular space includes a sweeping device for sweeping the annular space with an auxiliary fluid and an analyzing device for analyzing the composition of the auxiliary fluid at one accessible end of the pipe-line and at spaced locations along the pipe-line. A warning device connected to the analyzing device is operable when the analyzing device indicates a predetermined condition.
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