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TECHNICAL FIELD
The present invention relates to fuel injectors for internal combustion engines; more particularly, to a fuel injector with a built-in orifice for reducing pressure pulsations.
BACKGROUND OF THE INVENTION
Fuel injectors for controllably metering fuel to the combustion cylinders of internal combustion engines are well known. For ease and reliability in manufacturing, the fuel injectors typically are mounted by their inlet ends at appropriate intervals into a rigid fuel supply line harness, appropriately configured to place the injection end of each fuel injector into its corresponding injection socket in the manifold runner. Such a harness is known as a fuel injector rail, or simply a fuel rail.
In a typical direct injector fuel injection system, each injector is programmed to pulse or open every other revolution of the engine crankshaft. During an injector opening event in a direct injector fuel injection system, the measured fuel pressure in the fuel rail can instantaneously drop by more than 30 kPa, then can increase by more than 50 kPa after the injector closes. Although such high and low pressures can vary widely depending on rail volume, injector open/close time, and inlet line inner diameter, for example, in a typical four cylinder engine operating at 2000 RPM, the combined injectors can pulse at a rate of 66 pulses per second. In such injector-based systems, these pulses cause high frequency pressure waves of significant amplitude to propagate through the fuel rail(s) potentially causing erratic delivery of fuel to the cylinders.
The fuel rails themselves are typically bolted to the cylinder head. In one prior art design, the fuel rail is laterally offset from the position of the bolts which are secured to the cylinder head through brackets. The fuel rail is offset so the bolts are accessible when attaching or removing the fuel rail from the cylinder head. In this design, the brackets extend around a respective fuel injector socket, into which the inlet ends of the injectors are placed. This prior art design requires a jump tube leading from the rail to the respective injector socket.
One known method for reducing injector pressure pulsations is to include a restriction orifice in the fuel line leading to the injector. Due to the narrowing of the flow area, the restriction orifice breaks up and thus reduces the pressure pulsations. The location of the restriction orifice should be somewhere between the fuel rail and injector. In one known design, the restriction orifice is placed inside the jump tube. While this method is effective at reducing pressure pulsations, it also adds cost and complexity to the fuel system.
It would therefore be desirable to have a design and method for reducing pressure pulsations in a fuel line that does not increase cost or complexity to the system.
SUMMARY OF THE INVENTION
The present invention addresses the above need by providing a design and method for reducing pressure pulsations in a fuel line caused by the opening and closing of the fuel injectors. In a preferred embodiment, a restriction orifice is provided in the fuel injector filter of a respective fuel injector. The restriction orifice acts to break up and thus reduce or eliminate pressure pulsations through the fuel injector.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is an isometric view of a fuel rail and associated fuel injectors;
FIG. 2 is a partial cross-sectional view of a fuel injector as taken generally along the line 2 - 2 in FIG. 1 ; and
FIG. 3 is an enlarged detail view of the portion of the injector as indicated by the circled dash line labeled FIG. 3 in FIG. 2 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , there is seen a fuel rail 10 for mounting to an engine (not shown) via bracket 12 . The fuel rail 10 is laterally offset from the injector sockets 14 to provide access to the bolts 13 which pass through openings in bracket 12 . With the fuel rail 10 laterally offset from the injector sockets 14 , jump tubes 16 are required to provide a fluid path from the rail 10 to a respective injector socket 14 . Injector sockets 14 are known in the art and provide a coupling between a respective fuel injector 18 and the fuel rail 10 .
It is noted that fuel rail 10 and bracket 12 are shown for purposes of environment only, and the present invention may be used in any fuel delivery system having one or more fuel injectors.
Fuel injectors 18 each have a fuel inlet end 18 a and fuel outlet end 18 b . Fuel is thus directed through fuel outlet end 18 b upon the opening of the injector. As stated above, fuel injectors open and close very rapidly in order to provide the correct amount of fuel to the engine depending on the engine load condition. Without corrective measures being taken, unacceptable amounts of noise and vibration are created due to the rapid opening and closing of the fuel injectors as they pass fuel into the engine.
Referring to FIGS. 2 and 3 , a preferred embodiment of the invention is shown wherein a restriction orifice 20 is molded or otherwise formed in injector filter 22 . Fuel injector filters are known and include a filter media 24 disposed within a filter body 26 for removing small particulate from the fuel as the fuel enters the inlet end 18 a of the fuel injector 18 . The fuel injector filter body 26 may further include ribs 28 or other means for connecting the filter body to the fuel injector directly or via a filter connector 30 .
The fuel injector filter is positioned within the longitudinal passageway 18 c of the injector 18 to intercept and filter the fuel flowing therethrough prior to the fuel exiting the injector at outlet end 18 b . As seen best in FIG. 3 , a restriction orifice 20 is provided at the inlet end 22 a of filter 22 . The restriction orifice may be integrally molded with filter body 26 or may be a separate component which is connected to the filter body 26 adjacent filter inlet end 22 a or other suitable location within filter body 26 . Filter outlet end 22 b is generally positioned along the longitudinal axis of the injector passage 18 c.
It is noted that fuel filter bodies are typically injection molded from a plastic such as Nylon 66, for example. In a preferred embodiment, the restriction orifice 20 is between about 0.75 to about 2 mm in diameter although the final size will depend on the particular injector design employed. This restriction orifice is sufficient to substantially reduce or eliminate pressure pulsations in the fuel lines occurring as a result of the opening and closing of the fuel injectors.
While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.
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Apparatus and method for substantially reducing or eliminating pressure pulsations caused by the opening and closing of fuel injectors. A preferred embodiment provides a restriction orifice adjacent the inlet end of a fuel injector filter of a respective fuel injector.
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This is a division of application Ser. No. 735,310, filed Oct. 26, 1976, now U.S. Pat. No. 4,072,607, issued Feb. 2, 1978.
BACKGROUND OF THE INVENTION
The following invention relates to an anionic polymer having a skewed molecular weight distribution useful as a scale inhibitor and anti-precipitant. The anionic polymer may be made by a process which varies the amount of chain transfer agent during continuous polymerization, or the anionic polymer may be made by a physical blending.
The interest in scale inhibitors has been a continuous one. Many liquid flow applications require scale free operation, or, as a minimum, reduced scale buildup, to perform in a maintenance free and consequently economical manner. This is because these applications usually require heat transfer systems. For example, it is of particular importance to inhibit or minimize scale on the surfaces of boilers, heat exchangers, turbines, steam generators, pumps and steam and other fluid condensers. As a general statement, it can be said that any machine or other piece of equipment using water as at least one component and/or having a metal thermal transfer surface performs more efficiently when scale is kept to a minimum.
When certain alkaline earth metals are present in the liquid, there seems to be a great propensity for scale buildup. The alkaline earth metals preponderantly present and, therefore, of particular concern are calcium and magnesium.
There is, therefore, an almost continuous search in the art for compositions which will reduce or arrest the scale buildup of alkaline earth metal salts onto heat transfer and other surfaces.
As a general statement, there is an on-going need for scale inhibitors in industrial operations. Industrial processing with such equipment as air conditioning, refrigeration, heat exchange and evaporation, requires that the alkaline earth metal compounds be inhibited from depositing out of the water.
When certain industrial operations are being performed, for example, cooling operations, the alkaline earth metal compounds may be present in mineral matter such as slime or roiled sediment. These compounds would tend to cement themselves together as a strongly adherent scale which would interfere with the water flow.
In the prior art, anionic polymers have been used as scale inhibitors. See, for example, U.S. Pat. Nos. 3,663,448 and 3,463,730. These patents are incorporated herein by reference. Generally, scale inhibitors in the prior art have been used in the molecular weight range of about 500 to about 12,000.
There appears to be confusion in the art as to the definition of scale inhibitors and anti-precipitants. The following terms seem to have been used interchangeably either singly or in combination: scale inhibitor which would also include the term anti-scalant, anti-precipitant, anti-nucleation agent, and dispersing agent.
In this invention, the term scale inhibitor means a composition which inhibits the deposition of adherent scale deposits on the surfaces or parts of metal heat exchange surfaces. The term anti-precipitant means a composition which hinders the precipitation of a solid or the formation of turbidity in bulk solutions.
In certain applications there is a need for an anti-precipitant but not necessarily for a scale inhibitor. An example of this is in oil field brines where precipitated particles would tend to clog the porous rock. A scale inhibitor would not be necessary in this application because there are no heat transfer surfaces.
In other applications, the use of a scale inhibitor and anti-precipitant would complement each other. An example of this application is in recirculating cooling water systems where the heat transfer surfaces must be clean, and where the restricted flow areas must be clear of precipitated particles.
In yet another application, there is a need for a scale inhibitor without the need for an anti-precipitant. An example of this is in a boiler, where a scale inhibitor is necessary to reduce or eliminate the scale buildup in a boiler tube.
The confusion in the art has caused anti-precipitants to be used as scale inhibitors at a great loss of economic efficiency. However, as indicated above, anti-precipitants have been made for other applications. In fact, as indicated below, they require a different MW range.
SUMMARY OF THE INVENTION
The discovery has now been made that a composition of matter consisting of an anionic polymer of acrylamide having a skewed molecular weight distribution is useful as a scale inhibitor for controlling the deposition of adherent scales on the walls of vessels or pipes, and as an anti-precipitant for keeping alkaline earth cations in solution. The skewed molecular weight distribution is such that on a gel permeation chromatograph at least about 60% of the polymer has a molecular weight of about 500 to 2,000, and at least about 10% of the polymer has a molecular weight of about 4,000 to 12,000. The amount of polymer between the molecular weight range of about 2,000 to 4,000 could be between about zero and about 30%.
It is to be understood that the total amount of the anionic polymer of acrylamide having a skewed molecular weight distribution in all instances equals 100%. That is, the total amount of polymer is always 100% between the skewed molecular weight distribution of about 500 to 12,000. Thus, for example, if 60% of the polymer has a molecular weight of about 500 to 2,000, and 10% of the polymer has a molecular weight of about 4,000 to 12,000, then 30% of the polymer has a molecular weight of about 2,000 to 4,000. As the amount of polymer in the molecular weight ranges of about 500 to 2,000 and of about 4,000 to 12,000 is increased, the amount of polymer in the molecular weight range of about 2,000 to 4,000 will of necessity decrease so that the total amount of the anionic polymer of acrylamide having a skewed molecular weight distribution always equals 100%.
We have also discovered that this anionic polymer of acrylamide having a skewed molecular weight or bimodal distribution is useful as a scale inhibitor and as an anti-precipitant. As a scale inhibitor, the anionic polymer is used for controlling the deposition of adherent scales on the walls of vessels or pipes. As an anti-precipitant, the anionic polymer is used for keeping alkaline earth cations in solution.
The composition and use of the skewed molecular weight distribution anionic polymers we have discovered could be a copolymer of acrylic acid and acrylamide linkages in the mol ratios of about 20:1 to about 1:1. The acrylic acid linkages of the copolymer could then neutralize to an acrylate salt. A preferred acrylate salt is sodium acrylate. The sodium acrylate salt can be prepared by Example 1 herein.
We have discovered a synergistic effect when our skewed molecular weight anionic polymer of acrylamide is compared with a known scale inhibitor and a known anti-precipitant. That is, the polymer we have discovered having a skewed molecular weight distribution is more effective than known compositions of scale inhibitors and anti-precipitants. For an illustration of this synergistic effect, see Example 3.
The composition we have discovered, when used as a scale inhibitor and anti-precipitant, is effective because the scale inhibition is substantially provided by the lower molecular weight of the anionic polymer and the anti-precipitation is substantially provided by the higher molecular weight. That is, our synergistic effect occurs when a small amount (but large enough to maintain a peak in the gel permeation chromatograph) of the anionic polymer with an average molecular weight above 4,000 is added to a large amount of the anionic polymer with an average molecular weight below 2,000.
The use of the anionic polymer having a skewed molecular weight distribution as a scale inhibitor and anti-precipitant is effective in recirculating water systems, boilers, and in desalination systems. With regard to the latter, the anionic polymer of acrylamide having a skewed molecular weight distribution is effective in both evaporative and reverse osmosis desalination systems.
The skewed molecular weight distribution of the polymer we have discovered which is useful as a scale inhibitor and anti-precipitant exhibits a "threshold effect" or "threshold" phenomenon. This phenomenon is well known and is generally present in anti-precipitant compositions. A general description of this "threshold effect" can be found in U.S. Pat. No. 3,505,238, which is incorporated herein by reference.
DESCRIPTION OF THE PREFERRED EMBODIMENT
We have thus discovered a composition of an anionic polymer of acrylamide having a skewed molecular weight distribution. More specifically, the composition has a skewed molecular weight distribution wherein at least about 60% of the polymer has a molecular weight within the range of about 500 to 2,000, and at least about 10% of the polymer has a molecular weight of about 4,000 to 12,000. In a more preferred embodiment, about 70% of the polymer would have a molecular weight of about 500 to 2,000 and at least about 15% of the polymer would have a molecular weight of about 4,000 to 12,000. It is to be understood that the total amount of the anionic polymer of acrylamide having a skewed molecular weight distribution in all instances equals 100%. That is, the total amount of polymer is always 100% between the skewed molecular weight distribution of about 500 to 12,000. Because the process of manufacturing this skewed molecular weight anionic polymer is by a continuous polymerization or by a physical mixture of the polymer having a normal molecular weight distribution, some of the polymer will be present in the molecular weight of 2,000 to 4,000. Therefore, the inventors, in practice, can only define the skewed molecular weight distribution such that at least about 60% of the polymer has a molecular weight of about 500 to 2,000 and at least about 10% of the polymer has a molecular weight of about 4,000 to 12,000.
DESCRIPTION OF THE DRAWINGS
FIGS. 1, 2 and 3 are selected gel permeation chromatographs showing preferred embodiments of the invention. Gel permeation chromatography is the most effective method of analyzing the skewed molecular weight distribution of the anionic polymers discovered by the inventors. Gel permeation chromatography (GPC) is based upon the difference in effective size in solution of a given polymer. Effective size is dependent upon the molecular weight and the solvent used. The effective size is measured by injecting a polymer solution into a flowing stream of solvent which passes through porous, tiny, gel particles closely packed together in a column. Polymer molecules with small effective sizes (which is dependent upon low molecular weights) will penetrate more of the pores in the gel particles than molecules with high effective sizes (high molecular weight). Because the polymer molecules with small effective sizes will taken longer to emerge from the column than the polymer molecules with high effective sizes, the gel permeation chromatograph will be a size separation. By selection the proper instrument, the gel permeation chromatograph can be made to read out the molecular weight distribution of the polymer directly.
FIG. 4 shows a schematic view of a dynamic scale test apparatus.
FIG 2 is a representative gel permeation chromatograph showing the skewed molecular weight distribution of the anionic polymers discovered by the inventors. Specifically, in the molecular weight range of 4,000 to 12,000 the amount of polymer has been boosted artificially by at least about 10%. With a normal molecular weight distribution, the amount of polymer with a molecular weight in this range would normally be about 5%.
The utility of the skewed molecular weight distribution of the anionic polymers we have discovered are useful in any application where a scale inhibitor and/or an anti-precipitant is necessary. Specific applications for scale inhibition are in: recirculating water systems, boilers, industrial process water systems and evaporative desalination systems. The skewed molecular weight anionic polymers have use as anti-precipitants in the following application: oil field flooding and reverse osmosis desalination systems. It is to be understood that in some of these applications both a scale inhibitor and anti-precipitant will be used, e.g., the recirculating and industrial process water systems discussed above.
The inventors have discovered a synergistic effect when the skewed molecular weight anionic polymers are used jointly as a scale inhibitor and anti-precipitant. This disclosure is more fully described in the Examples which follow, specifically, see Example 3.
The relationship between scale inhibition and keeping alkaline earth cations in solution has certain theoretical concepts which may be an aid to understanding the invention. The synergistic effect of the anionic polymer appears to be caused by the skewed molecular weight or bimodal distribution which the inventors have discovered. That is, not only is the molecular weight of the anionic polymer skewed by artificially boosting the higher molecular weight range from about 4,000 to 12,000, but two modes or peaks have been achieved. See, e.g., FIG. 2. When comparing the figures, it appears that the synergistic relationship is stronger than the molecular weight distribution is skewed heavily in the lower molecular weight range, for example, from 500 to 2,000. That is, the smaller the amount of the anionic polymer added in the higher molecular weight range, the more defined is the peak of the scale inhibitor.
The following drawings and examples are preferred embodiments of the invention. They should not be construed and are not intended as a limitation to the scope of the claims.
As an aid to understanding the examples, the following list is pertinent.
Polymer A: U.S. Pat. No. 3,463,730 having a molecular weight of about 4,000 to 7,000.
Polymer B: U.S. Pat. No. 3,463,730 having a molecular weight of about 1000 to 2,000
Polymer C: Anionic Polymer of this invention made by continuous polymerization
Polymer D: Anionic Polymer of this invention made by physical mixing.
The accompanying drawings show the skewed molecular weight distribution for different percentages of polymer:
FIGS. 1 and 2 show preferred embodiments of the polymer made by continuous polymerization.
FIG. 3 shows a preferred embodiment made by physical mixing.
FIG. 4 shows a schematic view of a dynamic scale test apparatus.
EXAMPLE 1
The following illustrates the preparation of Polymer C by continuous polymerization.
Three streams are fed simultaneously over a 100-minute period to a kettle at reflux, containing respectively 76 weight percent acrylamide monomer as a water solution, 3 weight percent of ammonium persulfate catalyst based on the acrylamide monomer as a 35% weight water solution, and 16 weight percent of a chain transfer agent based on the acrylamide monomer as a 38% weight water solution. The chain transfer agent is fed for the first 15 minutes at a rate equivalent to 3 weight percent on monomer, and for the last 85 minutes at a rate equivalent to 16 weight percent on monomer. The resulting polymer has a "skewed" molecular weight distribution similar to FIG. 2. This polymer is hydrolyzed to about an 85%-95% polyacrylate, and about 5%-15% polyacrylamide copolymer.
EXAMPLE 2
The following illustrates the synergistic effect of the anionic polymer as a scale inhibitor and anti-precipitant on alkaline earth metal compounds in a simulated recirculating water system.
Polymer C was prepared as disclosed in Example 1. A dynamic scale test apparatus schematically described in FIG. 4 is used to measure scale deposit and turbidity. For a description of the apparatus see Preprints of Papers Presented at the 172nd Nat'l. Metting, San Francisco Aug. 30-Sept. 3, 1976, Amer. Chemical Soc., Div. of Environment Chem., Washington, D.C. 1976, which is incorporated herein by reference.
The example is prepared using a synthetic test water having a composition of 600 ppm Ca++ as CaCO 3 and 550 ppm alkalinity at CaCO 3 , at a pH of about 8.25. Referring to FIG. 4, the temperature control for recirculating water is set at 52° C. (125° F.) and the heaters on the testing are set to give skin temperatures on the copper thimble surface of approximately 90° C. The flow rates are set extremely low to vastly exaggerate scaling conditions. After six hours, scale deposit on a test surface and turbidity of the water is compared. The system run with no treatment becomes milky turbid almost immediately and produces about 150 mg scale deposit. Use of 8 ppm Polymer A reduces scale deposit to about 69 mg and the water is slightly hazy at the end of the 6 hour period. Use of 8 ppm Polymer B reduces the scale deposit to 17 mg but the solution becomes turbid in about 31/2 hours. However, the test using 8 ppm Polymer C reduces the scale deposit to about 16 mg and kept the solution from becoming turbid for at least the full six hours. Thus, Polymer C prepared according to this invention is a very effective scale inhibitor and anti-precipitant, i.e., it optimizes performance in both applications.
EXAMPLE 3
The following is another example of the synergistic effect of the anionic polymer having a skewed molecular weight distribution on alkaline metal compounds.
The polymer of Example 1 is used. A dynamic scale test apparatus described in FIG. 4 is used to measure scale deposit and turbidity.
A test solution was prepared having 275 ppm alkalinity as CaCO 3 , and 300 ppm Ca+ 2 as CaCO 3 at a pH of about 9.25. The system without treatment is immediately turbid and deposits about 150 mg. scale. The system treated by 4 ppm of Polymer A remains clear but deposits about 70 mg scale. The system treated by 4 ppm of Polymer B becomes rapidly turbid and deposits about 30 mg scale. The system treated by 4 ppm of Polymer C remains clear and deposits less than 12 mg of scale. Thus, Polymer C prepared according to this invention has a synergistic effect as a scale inhibitor and anti-precipitant, i.e., it optimizes performance in both applications.
EXAMPLE 4
The following illustrates a polymer of this invention made by a physical mixture.
Polymer D is synthesized by a physical mixing of one part of Polymer A with three parts Polymer B. The results of the synthesis showing a skewed molecular weight distribution of Polymer D are described graphically in FIG. 3. Polymer D when placed in the "high pH" scale inhibition test of Example 3 performed equivalent to Polymer C.
EXAMPLE 5
The following illustrates the effect of the anionic polymer of this invention as a scale inhibitor and anti-precipitant on alkaline earth metal compounds conducted by a jar test. This test simulates the effect of the anionic polymer in a boiler.
The polymer of Example 1 is used. Stock solutions are prepared having the following consistencies:
(1) 676 mg MgCl 2 .6H 2 O and 740 mg CaCl 2 in 250 ml deionized water
(2) 16 g Na 3 PO 4 .12H 2 O in 1000 ml deionized water
(3) 8 g NaOH in 1000 ml deionized water.
Two brine test solutions are then prepared by adding 5 ml of (1), 4.35 ml of (2), and 5.20 ml of (3). To the 5.20 ml of (3) in one test solution is added 5 ppm (real solids) of Polymer C. The other test solution is left blank.
The volume of the brine test solutions is run to 200 ml by the addition of deionized water. Each brine test solution gives 30 ppm of excess PO 4 -3 which will precipitate as a hydroxylapatite at a pH of b 11.5. 150 ml of the brine test solution is then placed in 400 ml beakers.
The beakers are placed in a pressure cooker at a temperature of 120° C. and a pressure of 15 psi for 15 minutes. The beakers are then removed from the pressure cooker and allowed to cool. After cooling to ambient temperature, the samples treated with Polymer C are hazy and contain a sludge. The untreated beaker forms hard, adherent deposits of hyroxylapatite.
EXAMPLE 6
The following illustrates the effect of the anionic polymer of this invention as a scale inhibitor and anti-precipitant on alkaline earth metal compounds in a simulated evaporative desalination system.
The polymer of Example 1 is used. Three stock solutions are prepared having the following consistencies:
(1) 563.5 g of MgSO 4 , 449.9 g of MgCl 2 and 128.8 g of KCl in 3.5 l of deionized water.
(2) 198.19 g CaCl 2 in 17.5 l of deionized water.
(3) 137.54 g NaHCO 3 in 17.5 l of deionized water.
Two test solutions are then prepared by adding 50 Ml of (1), 63.5 ml of (2), and 100 ml of (3) to two 500 ml beakers containing 16.91 g NaCl dissolved in 264 ml of deionized water. To the 100 ml of (3) in one test solution is added 5 ppm (real solids) of Polymer C plus 1.0 ml of 0.35 M Na 2 CO 3 . The other test solution is left blank.
The two beakers are then heated with stirring to the boiling point on a hot plate. The beakers are removed from the hot plate and allowed to cool at ambient temperature for one-half hour. At the end of the half hour period the treated sample is clear. The untreated samples are turbid and precipitate CaSO 4 .
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An anionic polymer of acrylamide having a skewed molecular weight distribution such that about 60% of said polymer has a molecular weight of about 500 to 2,000 and about 10% of said polymer has a molecular weight of about 4,000 to 12,000 has been discovered. The process of manufacturing this skewed molecular weight distribution anionic polymer is described. Its use as a scale inhibitor for controlling the deposition of adherent scales on the walls of vessels or pipes, and as an anti-precipitant for keeping alkaline earth cations in solution is also described. The use of the anionic polymer of acrylamide consisting of a skewed molecular weight could be used in recirculating water systems, boilers, and in evaporative and reverse osmosis desalination systems.
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FIELD OF THE INVENTION
The present invention relates to an advanced engine configuration of the eight-stroke internal combustion engine; and more particularly to an improvement on the coordination system of the eight-stroke engine.
The present invention can be used in the field of transportation vehicle, power generation.
BACKGROUND OF THE INVENTION
The present invention incorporates by reference the eight-stroke internal combustion engine, which was filed as U.S. Pat. No. 6,918,358 (application Ser. No. 10/619,147), and the engine of this type can also be abbreviated as the eight-stroke engine.
The original eight-stroke engine design has two major drawbacks, one is the uneven heat current distribution through the master cylinder wall and the master cylinder head, which reduces the durability of the eight-stroke engine in continuous heavy load operation, the other is the long mixing time required for the high-density-air to mix with the hot-combusting medium in the master cylinder during the injection process, which lowers the fuel efficiency of the eight-stroke engine that operates in high rpm condition. In order to overcome the above-mentioned technical difficulties, the present invention provides an improved configuration of the eight-stroke engine.
The present invention focuses on improving the fuel efficiency of the eight-stroke engine and shorten the mixing time of the high-density-air and the hot-combustion-medium in the master cylinder during the injection-process; as the reduction of the mixing time can directly decrease the heat current through the master cylinder wall, and the two-direction swirling effect can maintain the entire surface area of the master cylinder wall at about the same operating temperature, which results in a low heat loss environment for the cold-expansion-process, thereby achieving an overall fuel efficiency over 35% for the gasoline type eight-stroke engine and 45% for the diesel type eight-stroke engine even in small vehicle application.
In addition, it is also possible to employ an alternating-sparking-sequence with at least more than two spark plugs to enhance the two-direction swirling effect.
SUMMARY OF THE INVENTION
It is the main objective of the present invention to provide a swirl-injection type eight-stroke engine that can constantly vary the injection direction of the high-density-air from the slave cylinder into the master cylinder to shorten the mixing time and the provide a low heat loss environment in the master cylinder during the cold-expansion-process.
It is the second objective of the present invention to provide a swirl-injection type eight-stroke engine that can sustain long-term heavy load and high rpm operation.
It is the third objective of the present invention to provide a swirl-injection type eight-stroke engine that can maintain high fuel efficiency in both the light load and heave load conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A to FIG. 1H are the illustrative views of the swirl-injection type eight-stroke engine configured with 90 degree phase difference in different processes, wherein the top sectional view shows the valve conditions of the charge-input-valves and the charge-output-valves and the reverse-input-valve and the reverse-output-valve, wherein the shading of the valve indicates that the valve is shut.
FIG. 1A is the illustrative view of the swirl-injection type eight-stroke engine in the master-intake-process at about 30 degree of crankshaft reference angle, the master-intake-valve is open to admit air into the master cylinder during this process, wherein all the charge-output-valves and the charge-input-valves and the reverse-input-valve and the reverse-output-valves are shut.
FIG. 1B is the illustrative view of the swirl-injection type eight-stroke engine in the slave-intake-process at about 120 degree of crankshaft reference angle, the slave-intake-valve is open to admit air into the slave cylinder during this process, wherein all the charge-output-valves and the charge-input-valves and the reverse-input-valve and the reverse-output-valves are shut.
FIG. 1C is the illustrative view of the swirl-injection type eight-stroke engine in the master-compression-process at about 220 degree of crankshaft reference angle, the master piston is compressing the air in the master cylinder during this process, wherein all the charge-output-valves and the charge-input-valves and the reverse-input-valve and the reverse-output-valves are shut.
FIG. 1 Dcw is the illustrative view of the swirl-injection type eight-stroke engine in the slave-compression-process for clockwise injection at about 290 degree of crankshaft reference angle, the slave piston is compressing the air into the first-charge-channel during this process, wherein the first-charge-input-valve is opened with the camshaft system to allow the air to be compressed into the first-charge-channel.
FIG. 1 Dccw is the illustrative view of the swirl-injection type eight-stroke engine in the slave-compression-process for counterclockwise injection at about 1010 degree (the second round) of crankshaft reference angle, the slave piston is compressing the air into the second-charge-channel during this process, wherein the second-charge-input-valve is opened with the cam system to allow the air to be compressed into the second-charge-channel.
FIG. 1 Ecw is the illustrative view of the swirl-injection type eight-stroke engine in the hot-combustion-process for clockwise injection at about 365 degree of crankshaft reference angle, the air-fuel-mixture is ignited and combusted in the master cylinder during this process; wherein the second-charge-input-valve is opened with the cam system to compress the air into the first-charge-channel.
FIG. 1 Eccw is the illustrative view of the swirl-injection type eight-stroke engine in the hot-combustion-process for counter-clock-wise injection at about 1085 degree of crankshaft reference angle, the air-fuel-mixture is ignited and combusted in the master cylinder during this process; wherein the first-charge-input-valve is opened with the cam system to allow the air to be compressed into the first-charge-channel.
FIG. 1 Fcw is the illustrative view of the swirl-injection type eight-stroke engine in the injection-process for clockwise injection at about 420 degree of crankshaft reference angle, wherein the high-density-air of the first-charge-channel will open the first-charge-output-valve by the pressure difference, and a flow of high-density-air is injected from the first-charge-channel to create a clockwise swirling flow in the master cylinder during this process.
FIG. 1 Fccw is the illustrative view of the swirl-injection type eight-stroke engine in the injection-process for counterclockwise injection at about 1140 degree of crankshaft reference angle, wherein the high-density-air of the second-charge-channel will open the second-charge-output-valve by the pressure difference, and a flow of high-density-air is injected from the second-charge-channel to create a counterclockwise swirling flow in the master cylinder during this process.
FIG. 1G is the illustrative view of the swirl-injection type eight-stroke engine in the cold-expansion-process at about 460 degree of crankshaft reference angle, the cold-expansion-medium in the master cylinder continues to expand in both the master cylinder and the slave cylinder, and a flow of the cold-expansion-medium is flowing from the master cylinder into the slave cylinder through the reverse-channel during this process; all the charge-input-valves and the charge-output-valves are shut, the reverse-input-valve and the reverse-output-valve are open with the cam system during this process.
FIG. 1H is the illustrative view of the swirl-injection type eight-stroke engine in the slave-exhaust-process at about 535 degree of crankshaft reference angle, the cold-expansion-medium is expelled through the slave exhaust port during this process.
FIG. 1I shows an eight-stroke engine with built-in catalytic converter in the reverse-channel.
FIG. 1J is an isometric illustrative view of the valve positions without engine head and piston.
FIG. 1K is an isometric illustrative view of the master-intake-port, the slave-intake-port, the first-charge-channel, the second-charge-channel, the reverse-channel, and the slave-exhaust-port.
FIG. 2 shows an example of the charge-output-valve with the air-guiding-grooves.
FIG. 3 shows an advanced configuration of the eight-stroke engine, the flat type eight-stroke engine, wherein the pumping loss to increase fuel efficiency.
FIG. 4 shows the alternating-firing cylinder arrangement of the eight-stroke engine, wherein the master piston and the piston cylinder are coupled to the master crankshaft and the slave crankshaft in an alternative order.
FIG. 5 shows an alternative cylinder arrangement of the eight-stroke engine, the radial type eight-stroke engine; wherein the mechanical loss and the engine vibration can be greatly reduced.
Operation Table. 1 . Part.A and Operation Table. 1 Part.B show the relation between the eight-stroke-operation and the 8-process-sequence with the crankshaft reference angle scale, wherein the swirl-injection type eight-stroke engine is configured with 90 degree phase-difference.
Operation Table. 2 shows the relation between the eight-stroke-operation and the 8-process-sequence with the crankshaft reference angle scale, wherein the swirl-injection type eight-stroke engine is configured with 75 degree phase-difference.
Operation Table. 3 shows the relation between the eight-stroke-operation and the 8-process-sequence with the crankshaft reference angle scale, wherein the swirl-injection type eight-stroke engine is configured with 150 degree phase-difference.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The swirl-injection type eight-stroke engine is an advanced eight-stroke engine developed from the eight-stroke internal combustion engine, which also operates in the basis of the eight-stroke-operation, the eight-stroke-operation consists of eight piston stroke performed by the master piston and the slave piston, which are the master-intake-stroke, the slave-intake-stroke, the master-compression-stroke, the slave-compression-stroke, the master-expansion-stroke, the slave-expansion-stroke, the master-exhaust-stroke, the slave-exhaust-stroke; however, to precisely describe the detailed operation of the swirl-injection type eight-stroke engine, the eight-stroke-operation will be elaborated with the 8-process-sequence, which describes the eight-stroke-operation in respect to the air flows in the master cylinder and the slave cylinder.
The master-intake-stroke, the master-expansion-stroke, the slave-intake-stroke and the slave-expansion-stroke are down-strokes; the master-compression-stroke, the master-exhaust-stroke, the slave-compression-stroke and the slave-exhaust-stroke are up-strokes.
The basic components of the swirl-injection type eight-stroke engine comprises a set of a master cylinder and a slave cylinder and an alternating-charge cam system; said master cylinder includes a master piston, said slave cylinder includes a slave piston, wherein said master piston and said slave piston must have a phase-difference between 60 degree and 150 degree to perform the 8-process-sequence.
Operation Table. 1 to Operation Table. 3 demonstrate the relationship between the 8-process-sequence and the eight-stroke-operation with various phase-difference configurations, it should be noted that the strokes mentioned in the eight-stroke-operation (such as the master-intake-stroke and the slave-intake-stroke) refers only to the downward motion or the upward motion of the master piston and the slave piston, the actual valve open-time or the air flow direction is defined with the 8-process-sequence; for example the master-intake-stroke is from 0 degree to 180 degree of crankshaft reference angle but the master-intake-process may be as long as 270 degree with the master intake valve opening opened from 0 degree to 270 degree; for another example, the master-exhaust-stroke is from 540 degree to 720 degree but the slave-exhaust-process of the eight-stroke engine is solely depending on the actuation time of the slave-exhaust-valve. Therefore the present invention will use 8-process-sequence to provide a better understanding of the eight-stroke engine concept.
The 8-process-sequence includes the master-intake-process, the slave-intake-process, the master-compression-process, the slave-compression-process, the hot-expansion-process, the injection-process, the cold-expansion-process, the slave-exhaust-process.
The master-intake-process is the process that the master-intake-valve opens to provide the air into the master cylinder.
The slave-intake-process is the process that the slave-intake-valve opens to provide the air into the slave cylinder.
The master-compression-process is the process that the master piston compresses the air in the master cylinder after the master-intake-valve is shut.
The slave-compression-process is the process that the slave piston compresses the air into one of the first-charge-channel and the second-charge-channel with the alternating-charge cam system; the first-charge-input-valve and the second-charge-input-valve will be actuated in an alternating order, so that one of the first-charge-channel and the second-charge-channel is disabled in an alternating order; for example when the first-charge-input-valve is open to compress the air into the first-charge-channel, the second-charge-input-valve will be shut to disable the second-charge-channel in the first round of the eight-stroke-operation; in the next round of the eight-stroke-operation, the second-charge-input-valve is open to compress the air into the second-charge-channel and the first-charge-input-valve is shut to disable the first-charge-channel.
The slave-compression-process will be terminated after one of said first-charge-channel and the second-charge-channel has a higher air-pressure than the combusting pressure of the hot-combustion-medium in the master cylinder.
During the master-intake-process and the master-compression-process, the fuel will be provided into the master cylinder with the fuel-supplying means; said fuel-supplying means can be a fuel-injector, a carburetor, a fuel pump, or a direct-fuel-injection depending on the fuel type.
The hot-combustion-process is the process that the master cylinder ignites the air-fuel-mixture with its associated ignition means (such as spark plugs or direction injection nozzles or other currently known ignition methods), the ignition timing can be set any point between 35 degree before the TDC of the master piston and 40 degree after the TDC of the master piston (for late ignition timing such as 40 degree after the TDC position, all the following processes will be shifted backward accordingly, and a larger phase-difference configuration is required).
During the hot-combustion-process, the air-fuel-mixture is combusted as the hot-combustion-medium in the master cylinder, at the same time the first-charge-output-valve and the second-charge-output-valve and the reverse-input-valve are shut. As the master piston reciprocates downward to allow the pressure of the hot-combustion-medium to drop below the threshold pressure for the initiation of the injection-process, then the hot-combustion-process will be terminated.
The injection-process will be initiated after one of the first-charge-channel and the second-charge-channel reaches a higher air-pressure than the pressure of the hot-combustion-medium, the high-density-air of the enabled charge-channel will overcome the combined force of the spring-tension on the associated charge-output-valve and the combustion pressure of the hot-combustion-medium, thereby injecting the high-density-air into the master cylinder within an extremely short time interval (about 10 milliseconds to 3 milliseconds in 2000 rpm operation).
During the injection-process the high-density-air is injected into the master cylinder at an angle to create a swirling effect while the high-density-air is mixing with the hot-combustion-medium, for the easy of referencing, the mixed medium is referred to as the cold-expansion-medium, since the mixing action will convert the carbon-monoxide into the carbon-dioxide and release more energy for expansion at low temperature (about 400 degree Celsius to 800 degree Celsius), and because of the low temperature characteristic and the swirling effect, the master cylinder wall will conduct less heat current from the cold-expansion-medium, thus reducing the heat loss.
The first-charge-output-valve and the second-charge-output-valve are preferably constructed to inject the high-density-air in different swirling direction, for example, in the first embodiment, the first-charge-output-valve is injecting to generate a clockwise swirling (as observed in the top sectional view), whereas the second-charge-output-valve is injecting to generate a counterclockwise swirling, therefore the injection-process and the cold-expansion-process of the first round of the 8-process-sequence will have a clockwise swirling effect to the cold-expansion-medium in the master cylinder, while the injection-process and the cold-expansion-process of the second round of the 8-process-sequence will have a counterclockwise swirling effect to the cold-expansion-medium in the master cylinder.
The cold-expansion-process is the process that the cold-expansion-medium expands in both the master cylinder and the slave cylinder; during this process the reverse-input-valve and the reverse-output-valve are cam-actuated to allow the cold-expansion medium to flow through the reverse-channel into the slave cylinder, while the first-charge-output-valve and the second-charge-output-valve are shut (which allows the first-charge-channel and the second-charge-channel to cool down); the reverse-input-valve and the reverse-output-valve will start to open after the slave piston has started the slave-expansion-stroke.
For increasing the expansion efficiency of the cold-expansion-process and the reducing the pollution in light load condition, the reverse-channel can include a built-in catalytic converter, so the cold-expansion-medium of the master cylinder will pass through the catalytic converter before entering the slave cylinder.
The slave-exhaust-process is the process that the cold-expansion-medium is expelled out of the slave cylinder with a cam-actuated slave-exhaust-valve during the later part of the slave-expansion-stroke and the entire slave-exhaust-stroke.
For the basic configuration as in the first embodiment, almost all the cold-expansion-medium in the master cylinder is transferred into the slave cylinder to be expelled through the slave-exhaust-port (a portion of the cold-expansion-medium is remained due to the compression ratio in the master cylinder).
For the advanced configuration used in the high speed engine applications, an auxiliary-exhaust-valve can be installed in the master cylinder, which can be actuated to open between 540 degree and 720 degree of crankshaft reference angle to reduce the pumping loss and the heat loss through the reverse-channel in high speed engine applications, the slave exhaust valve will still open until the end of the slave-exhaust-stroke to expel the cold-expansion-medium out of the slave cylinder.
Now referring to FIG. 1A to FIG. 1H for the structural description of the first embodiment, the basic components of the swirl-injection type eight-stroke engine are labeled as follows, the master-intake-port 101 , the master-intake-valve 112 , the master piston 111 , the master cylinder 110 , the slave-intake-valve 122 , the slave-intake-port 102 , the slave-exhaust-port 109 , the slave-exhaust-valve 129 , the slave piston 121 , the slave cylinder 120 , the reverse-channel 160 , the reverse-input-valve 161 , the reverse-output-valve 162 , the first-charge-channel 130 , the second-charge-channel 140 , the first-charge-input-valve 131 , the second-charge-input-valve 141 , the first-charge-output-valve 132 , the second-charge-output-valve 142 , the alternating-charge cam system 180 , the ignition means 118 , the fuel-supplying means 119 .
The first embodiment is based on the configuration of 90 degree phase difference, it should be noted that the phase-difference can vary from 60 degree to 150 degree to operate with the 8-process-sequence while sustaining a reasonable fuel efficiency over 35%; the 8-process-sequence of 90 degree phase-difference are shown in Operation Table. 1 , while the alternative configurations are demonstrated in Operation Table. 2 and Operation Table. 3 with various phase-differences (75 degree and 150 degree).
Now explaining FIG. 1A to FIG. 1H with reference to Operation Table. 1 Part A and Operation Table. 1 Part B:
As shown in FIG. 1A the eight-stroke engine is in the beginning of the master-intake-process at about 30 degree of crankshaft reference angle, the master piston 111 is moving downward, the master-intake-valve 112 is open to admit the air into the master cylinder 110 , the slave piston 121 is moving upward to expel the cold-expansion-medium of the last round of the eight-stroke-operation.
As shown in FIG. 1B the eight-stroke engine is in the beginning of the slave-intake-process at about 120 degree of crankshaft reference angle, the slave piston 121 is moving downward, the slave-intake-valve 122 is open to admit the air into the slave cylinder 120 , the master cylinder 110 is in the later stage of the master-intake-process.
As shown in FIG. 1C the eight-stroke engine is in the beginning of the master-compression-process at about 220 degree of crankshaft reference angle, the master-intake-valve 112 is shut, the reverse-input-valve 161 is shut, and the air in the master cylinder 110 is compressed with the master piston 111 .
As shown in FIG. 1 Dcw the eight-stroke engine is in the beginning of the slave-compression-process at about 290 degree of crankshaft reference angle, the slave-intake-valve 122 is shut, the first-charge-input-valve 131 is open to allow the air into the first-charge-channel 130 , (the second-charge-channel 140 is disabled in the first round of the eight-stroke-operation in this configuration, the first-charge-input-valve 131 and the second-charge-input-valve 141 will be actuated in alternating turns to enable one of the first-charge-channel 130 and the second-charge-channel 140 ).
As shown in FIG. 1 Ecw the eight-stroke engine is in the beginning of the hot-expansion-process at about 365 degree of the crankshaft reference angle, the air-fuel-mixture are combusting in the master cylinder 110 as the hot-combustion-medium with the ignition means 118 , at the same time the enabled charge-channel (the first-charge-channel 130 ) will continue to increase its air-pressure therein until the threshold pressure of the initiation of the injection process is reached.
The threshold pressure of the initiation of the injection process is defined as the air-pressure that is sufficient to overcome the spring-tension of its associated charge-output-valve and the combustion pressure of the hot-combustion-medium; depending on the configurations of the eight-stroke engine, the injection-process may be initiated at any point between the first 30 degree of the master-expansion-stroke and the last 30 degree of the slave-compression-stroke; in other words the injection-process may start between 30 degree after the TDC position of the master piston (the master-expansion-stroke) and 30 degree before the TDC position of the slave piston (the slave-compression-stroke).
The total duration of injection-process may range from 5 degree to 60 degree of crankshaft rotation depending on the spring strength and the engine rpm.
As shown in FIG. 1 Fcw the eight-stroke engine is in the beginning of the injection-process at about 420 degree of crankshaft reference angle, the high-density-air in the enabled charge-channel (first-charge-channel 130 ) will be injected into the master cylinder 110 to swirl and mix with hot-combustion-medium to form a cold-expansion-medium; the enabled charge-output-valve (the first-charge-output-valve 132 ) may be shut before the slave piston 121 reaches TDC position if the air-pressure of the enabled charge-channel drops to below the pressure of the master cylinder 110 ; as the alternating-charge cam system 180 will enable each charge-channel in an alternating order, so that the two-direction swirling effect will reduce the surface temperature of the master cylinder wall and the master cylinder head, thereby maintaining a low heat loss environment for power generation.
As shown in FIG. 1G the eight-stroke engine is in the beginning of the cold-expansion-process at about 460 degree of crankshaft reference angle, the cold-expansion-medium will then expand in both the master cylinder 110 and the slave master cylinder 120 after both the reverse-input-valve 161 and the reverse-output-valve 162 are cam-actuated to establish a direct air passage from the master cylinder to the slave cylinder (the first-charge-channel 130 and the second-charge-channel 140 should be considered as one-way channel from the slave cylinder 120 to the master cylinder 110 ).
As shown in FIG. 1H the eight-stroke engine is in the beginning of the slave-exhaust-process at about 535 degree of crankshaft reference angle (the slave-exhaust-valve 129 may open in the range from 520 degree of crankshaft reference to about the end of the slave-exhaust-stroke depending on the engine applications); during this process, the cold-expansion-medium is expelled through the slave-exhaust-port 109 .
For the second round of the eight-stroke-operation (720 degree to 1530 degree of crankshaft reference), wherein FIG. 1A , FIG. 1B , FIG. 1C , FIG. 1G , FIG. 1H are basically the same as in the first round of the eight-stroke-operation, except the following FIG. 1 Dccw, FIG. 1 Eccw, and FIG. 1 Fccw.
As shown in FIG. 1 Dccw is the beginning of the slave-compression-process at about 1010 degree of crankshaft reference angle, the slave-intake-valve 122 is shut, the second-charge-input-valve 132 is open to allow the air into the second-charge-channel 130 , the first-charge-channel 130 is disabled in this second round of the eight-stroke-operation.
As shown in FIG. 1 Eccw is in the beginning of the hot-expansion-process at about 1085 degree of the crankshaft reference angle, the air-fuel-mixture are combusting in the master cylinder 110 as the hot-combustion-medium with the ignition means 118 , at the same time the enabled charge-channel (the second-charge-channel 140 ) will continue to increase its air-pressure therein until the threshold pressure of the initiation of the injection process is obtained.
As shown in FIG. 1 Fccw is in the beginning of the injection-process at about 1140 degree of crankshaft reference angle, the high-density-air in the enabled charge-channel (second-charge-channel 140 ) will be injected into the master cylinder 110 to swirl and mix with hot-combustion-medium to form a cold-expansion-medium; the enabled charge-output-valve (the first-charge-output-valve 131 ) may be shut before the slave piston 121 reaches TDC position if the air-pressure of the enabled charge-channel drops to below the overall pressure in the master cylinder 110 ; as the alternating-charge cam system 180 will enable each charge-channel in an alternating order, so that the two-direction swirling effect will reduce the surface temperature of the master cylinder wall and the master cylinder head and maintain a low heat loss environment for power generation.
Referring to FIG. 1I , the reverse-channel 160 has included a built-in catalytic converter 163 , so the cold-expansion-medium of the master cylinder 110 will pass through the catalytic converter before entering the slave cylinder.
Various cylinder arrangements can be employed with the swirl-injection type eight-stroke engine, the master piston and the slave-piston can be connected with single crankshaft or two separate crankshafts coupled with gears.
A simple double-crankshaft-inline cylinder arrangement can be constructed with an inline block for slave cylinders and an inline block for master cylinders, wherein the master piston and the slave piston will be connected with separate crankshafts.
An example of the alternative cylinder arrangements is to dispose the master cylinder and the slave so that the master piston and the slave piston reciprocate towards each other as in the flat-type cylinder arrangement as shown in FIG. 3 , wherein the cold-expansion-medium can expand with minimum energy due to the inertia of the air-flow, the components are labeled as the master-crankshaft 301 , the master cylinder block 310 , the engine head 305 , the slave cylinder block 320 , the slave-crankshaft 302 .
The first-charge-output-valve and the second-charge-output valve can be constructed with the air-guiding-grooves as shown in FIG. 2 to enhance the mixing effect during the injection process. Another example of the cylinder arrangements is shown in FIG. 4 , wherein the master cylinder and the slave cylinder are connected to the first crankshaft and the second crankshaft in alternating order; the first master cylinder 430 is co-acting with the first slave cylinder 432 , the second master cylinder 440 is co-acting with the second slave cylinder 442 , the third master cylinder 450 is co-acting with the third slave cylinder 452 , the fourth master cylinder 460 is co-acting with the fourth slave cylinder 462 ; the first master cylinder 430 and the third master cylinder 450 is connected to the first crankshaft 401 , the second master cylinder 440 and the fourth master cylinder 460 is connected to the second crankshaft 402 , whereas the first slave cylinder 432 and the third slave cylinder 452 is connected to the second crankshaft 402 , the second slave cylinder 442 and the fourth slave cylinder 462 is connected to the first crankshaft 401 .
For further improving the fuel efficiency by reducing the mechanical loss and vibration, a radial type eight-stroke engine can be constructed as in FIG. 5 , wherein, the radial type eight-stroke consists of at least 3 pairs of co-acting master cylinder 501 and slave cylinder 502 ; the components in FIG. 5 are labeled as the master cylinder 501 , the slave cylinder 502 , the output shaft 500 , the master-intake-port 512 , the slave-intake-port 523 , the slave-exhaust-port 528 .
The swirl-injection type eight-stroke engine of the gasoline type can further include an alternating-spark system with more than two spark plugs, wherein the spark plugs are ignited in different positions to optimize the two-direction swirling effect in the master cylinder.
For large engine application, the swirl-injection type eight-stroke engine can further comprises additional charge-channels with the required charge-output-valves and the charge-input valves to operate with the alternating-charge cam system; for example, when three charge-channel is installed, the charge-output-valve of each charge-channel can be constructed with three different injection angles so that the high-density-air and the hot-combustion-medium can swirl and mix in three different directions to reduce the heat loss in the master cylinder.
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The present invention provides a swirl-injection type eight-stroke engine capable of constantly varying the injection-direction of the high-density-air from the slave cylinder, thereby effectively circulating the high-density-air around the master cylinder wall and master cylinder head during the injection process to speed up the mixing of the high-density-air and the hot combustion medium in the master cylinder, furthermore the hot spots in the master cylinder head and the master cylinder wall are eliminated with the two-direction swirling effect during the cold-expansion process.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present disclosure relates to golf equipment, particularly a golf bag with a hidden club protection cover and a slide structure.
2. Descriptions of the Related Art
Currently, a known golf bag is usually provided with a club protection device based on two types as follows: a soft club protection device comprises a lid which is manufactured of the golf bag's shell fabric, lifted for a club removed therefrom, and put back and linked with buttons during transportation or storage; a club protection device with a hard shell cover lid manufactured of PE-based molded plastic is connected to the golf bag with buttons and removed for takeout of a club by a user who needs to find a place to store the separated lid at a golf course. In addition, it is usual to discover appearance damages or scratches which are induced by collisions among clubs held in a soft club protection device during transportation and affect a club's service life.
SUMMARY OF THE INVENTION
The present disclosure is intended to provide a golf bag which can be conveniently and safely used, carried and transported with no lid removed.
The technical measures in the present disclosure are described as follows: a golf bag comprising a bag body, a club protection cover axially sliding along and disposed in a golf bag mouth at the upper end of the bag body, and a slide mechanism located inside the club protection cover in which the club protection cover through the slide mechanism is connected to the golf bag mouth.
The slide mechanism in the present disclosure consists of slide bars axially disposed in the golf bag mouth and slide tabs at the inner lower wall of the club protection cover: each of the slide bars comprises a groove and a stop block at the groove's top; each of the slide tabs has an I-shaped appearance and allows one end to be connected to the club protection cover and the other end to be inserted into the groove's lower end and slide vertically along the slide bar.
The slide bars in the present disclosure are connected to an upper retaining ring and a lower retaining ring for secure connection to the slide bars at their upper and lower ends, respectively: the upper retaining ring is flexibly held in the club protection cover and securely links a bag head frame which is fixed at the inner wall of the upper retaining ring and comprises grids distributed inside.
The upper retaining ring, the lower retaining ring and the slide bars in the present disclosure are externally covered by a hollow plastic drum; the lower retaining ring is fixed on the inner wall of the hollow plastic drum; the upper retaining ring and the plastic drum allow the club protection cover to be held in between.
The number of slide bars in the present disclosure is from 2 to 4.
The slide mechanism in the present disclosure consists of slide bars axially disposed in the golf bag mouth and slide bushings installed in the club protection cover: each of the slide bushing is held in the slide bar; the slide bars are securely connected to a bag head frame atop; the bag head frame is installed in the club protection cover and comprises grids distributed inside.
The slide bars in the present disclosure are securely connected to a base of the bag body underneath: the base comprises ports inserted by the slide bars' lower ends from below.
The number of slide bars in the present disclosure is from 2 to 4.
The slide mechanism in the present disclosure consists of a hollow plastic drum disposed in the golf bag mouth and a club protection cover inside the plastic drum: the club protection cover is provided with a first rib around the lower outer circumference; the plastic drum is provided with a second rib around the upper inner circumference; the club protection cover is provided with a bag head frame at the central section; the bag head frame comprises grids distributed inside.
The club protection cover in the present disclosure is provided with a lid atop which is opened upward and links the club protection cover with a zipper.
In contrast to the current art, the golf bag in the present disclosure features a club protection cover sliding inside a bag body. A user lifting a lid on the club protection cover and allowing the club protection cover to slide downward can take a club away; a user removing the club protection cover from the bag body and closing the lid can protectively conceal used clubs in the golf bag, prevent clubs from damages or scratches during transportation or storage, and extend service lives of clubs without any club lost.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective exploded view illustrating a golf bag of the present disclosure in the first embodiment.
FIG. 2 is a perspective view illustrating a golf bag of the present disclosure in the first embodiment.
FIG. 3 is a schematic view which illustrates slide bars linking upper and lower retaining rings in the first embodiment.
FIG. 4-1 is schematic view illustrating a slide tab's structure in the first embodiment.
FIG. 4-2 is a sectional view of a slide bar in the first embodiment.
FIG. 5 is a schematic view illustrating a club protection cover of a golf bag in the first embodiment.
FIG. 6 is a perspective view illustrating a golf bag of the present disclosure in the second embodiment.
FIG. 7 is a perspective exploded view illustrating a golf bag of the present disclosure in the second embodiment.
FIG. 8 is a perspective view illustrating a golf bag of the present disclosure in the third embodiment.
FIG. 9 is a sectional view illustrating a golf bag of the present disclosure in the third embodiment.
FIG. 10 is a schematic view illustrating a golf bag with clubs held.
FIG. 11 is a schematic view illustrating a golf bag which has been transported or stored.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The detailed technical measures of the present disclosure are described in embodiments hereinafter.
As shown in FIGS. 1, 2 and 10 , a golf bag of the present disclosure in the first embodiment comprises: a bag body 1 ; a club protection cover 3 which develops a cylinder and axially slides along and is disposed in a golf bag mouth 2 at the upper end of the bag body 1 ; a lid 18 installed above the club protection cover 3 and linking the club protection cover 3 with a zipper; a slide mechanism 4 located inside the club protection cover 3 in which the club protection cover 3 through the slide mechanism 4 is disposed and consisting of slide bars 8 axially installed inside the golf bag mouth 2 , slide tabs 5 at the inner lower wall of the club protection cover 3 , and an upper retaining ring 7 and a lower retaining ring 9 atop and underneath the slide bars 8 , respectively. Each of the four slide bars 8 symmetrically arranged and separated by 90 degrees comprises a groove 81 with an opening at the bottom of the slide bar 8 and a stop block 82 atop the groove 81 ; each of the four slide tabs 5 situated at one side of the club protection cover 3 and coordinating the corresponding slide bars 8 for installation has an I-shaped appearance comprising a minor horizontal member, which is less than a major one in length and inserted into the groove 81 from below for sliding vertically along the slide bar 8 , and a major member fixed on the club protection cover 3 which relies on the slide tabs 5 to slide vertically along the slide bars 8 . The upper retaining ring 7 is flexibly held in the club protection cover 3 which is externally covered by a removable hollow plastic drum 10 ; the lower retaining ring 9 is internally fixed on the plastic drum 10 ; the upper retaining ring 7 links a bag head frame 6 which is fixed at the inner wall of the upper retaining ring 7 with rivets and integrated with the slide mechanism 4 ; the bag head frame 6 held in the club protection cover 3 comprises grids 11 distributed inside and keeps immobile (or develops a gap between the bag head frame 6 and the club protection cover 3 ) when the club protection cover 3 moves upward along the slide bars 8 (or downward until the upper edge of the lower retaining ring 9 ).
As shown in FIG. 3 , the slide mechanism 4 of the present disclosure in the first embodiment consists of the circular upper retaining ring 7 , the circular lower retaining ring 9 and the laminar slide bars 8 : the upper retaining ring 7 is securely connected to each of the slide bars 8 with three rivets atop; the lower retaining ring 9 is securely connected to each of the slide bars 8 with three rivets underneath; each of the slide bars 8 comprises a groove 81 with an opening which extends downward and is terminated by a stop block 82 atop the slide bar 8 in order to keep the slide tab 5 sustained by the groove 8 .
As shown in FIG. 4-1 , the slide tab 5 of the present disclosure in the first embodiment has an I-shaped appearance comprising a minor horizontal member, which is less than a major one in length and inserted into the groove 81 from below for sliding vertically along the slide bar 8 .
As shown in FIG. 4-2 , the groove 81 of the slide bar 8 in the first embodiment develops a hollow rectangular structure which comprises a notch opened at the middle section of the groove 81 and accommodates the minor horizontal member sliding in the groove 81 .
As shown in FIG. 5 , the club protection cover 3 of a golf bag in the first embodiment is a cylinder developing an opening underneath and linking the lid 18 atop with zippers, rivets the slide tabs 5 which correspond to the slide bars 8 and are located at the inner lower wall near the opening and held in the slide bars 8 , and relies on the slide tabs 5 to slide vertically along the slide bars 8 .
The golf bag in the embodiment has three different specifications as follows:
Type I: club protection cover 3 : height=480 MM, diameter=226 MM; slide tab 5 separated from the club protection cover's bottom by 30 mm; plastic drum 10 : height=850 MM, diameter=239 MM; slide bar 8 : length=520 MM, width=28 MM; slide tab 5 : sliding distance=430 MM; upper retaining ring 7 : diameter=220 MM, height=30 MM; lower retaining ring 9 : diameter=220 MM, height=30 MM; slide tab: major horizontal member's length=45 MM, minor horizontal member's length=25 MM, length of a connecting piece between major and minor horizontal members=5 MM.
Type II: club protection cover 3 : height=480 MM, diameter=213 MM; slide tab 5 separated from the club protection cover's bottom by 40 mm; plastic drum 10 : height=850 MM, diameter=226 MM; slide bar 8 : length=520 MM, width=28 MM; slide tab 5 : sliding distance=430 MM; upper retaining ring 7 : diameter=207 MM, height=30 MM; lower retaining ring 9 : diameter=207 MM, height=30 MM; slide tab: major horizontal member's length=45 MM, minor horizontal member's length=25 MM, length of a connecting piece between major and minor horizontal members=5 MM.
Type III: club protection cover 3 : height=480 MM, diameter=239 MM; slide tab 5 separated from the club protection cover's bottom by 40 mm; plastic drum 10 : height=850 MM, diameter=251 MM; slide bar 8 : length=520 MM, width=28 MM; slide tab 5 : sliding distance=430 MM; upper retaining ring 7 : diameter=232 MM, height=30 MM; lower retaining ring 9 : diameter=232 MM, height=30 MM; slide tab: major horizontal member's length=45 MM, minor horizontal member's length=25 MM, length of a connecting piece between major and minor horizontal members=5 MM.
As shown in FIGS. 6, 7 and 10 , a golf bag of the present disclosure in the second embodiment comprises: a bag body 1 ; a club protection cover 3 which develops a cylinder and axially slides along and is disposed in a golf bag mouth 2 at the upper end of the bag body 1 ; a lid 18 installed above the club protection cover 3 and linking the club protection cover 3 with a zipper; a slide mechanism 4 located inside the club protection cover 3 and consisting of four slide bars 12 , all of which are axially disposed in the golf bag mouth 2 and symmetrically arranged and separated by 90 degrees, and four slide bushings 13 connected to the inner lower wall of the club protection cover 3 and corresponding to and held in the slide bars 12 ; a bag head frame 6 located at tops of the slide bars 12 , comprising ports through which the slide bars 12 are securely held with screws, and externally covered by the club protection cover 3 ; grids 11 distributed in the bag head frame 6 ; a base 14 situated at the bottom of the bag body 1 and developing ports 15 in which the ends of the slide bars 12 are securely inserted wherein each of the ports 15 is coupled with a screw to fix the slide bar 12 and keep the bag head frame 6 immobile with the club protection cover 3 shifted upward along the slide bar 12 .
As shown in FIGS. 8, 9 and 10 , a golf bag of the present disclosure in the third embodiment comprises: a bag body 1 ; a club protection cover 3 which develops a cylinder and axially slides along and is disposed in a golf bag mouth 2 at the upper end of the bag body 1 ; a lid 18 installed above the club protection cover 3 and linking the club protection cover 3 with a zipper; a slide mechanism consisting of a hollow plastic drum 10 disposed in the golf bag mouth 2 and a club protection cover 3 sliding inside the plastic drum 10 ; a first rib 16 around the lower outer circumference of the club protection cover 3 ; a second rib 17 around the upper outer circumference of the club protection cover 3 ; a bag head frame 6 at the central section inside the club protection cover 3 ; grids 11 distributed inside the bag head frame 6 . As such, the upper surface of the first rib 16 contacts the lower surface of the second rib 17 and prevents the club protection cover 3 from not only upward movement but also separation from the plastic drum 10 as well as the golf bag mouth 2 when the club protection cover 3 is shifted to the top along the plastic drum 10 .
As shown in FIG. 10 , the club protection cover 3 is concealed by the golf bag mouth 2 with clubs held in a golf bag of the present disclosure.
As shown in FIG. 11 , a golf bag to be transported or stored is covered and protected by the lid 18 with a zipper when the club protection cover 3 is lifted from the golf bag mouth 2 . The golf bag of the present disclosure with a club protection cover integrated is characteristic of clubs concealed in the golf bag sealed by a lid during transportation or storage with the club protection cover lifted and covering clubs. Moreover, the user-friendly golf bag allows clubs to be held inside the golf bag along slide bars with neither appearance nor functions affected when a club is taken through the opened lid.
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A golf bag comprises a bag body. A club protection cover capable of axially sliding along a golf bag mouth is disposed in the golf bag mouth at an upper end of the bag body. A slide mechanism is disposed inside the club protection cover. The club protection cover is connected in the golf bag mouth through the slide mechanism. The golf bag can prevent damage to the club, and extend the service life of the club.
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FIELD OF THE INVENTION
This invention relates to electronic musical tone synthesizers, and more particularly, is concerned with a digital tone generator producing an ensemble effect.
BACKGROUND
An ensemble effect is achieved when a musical tone sounds like it comes from more than one instrument. A note played by a group of violins sounds different than the same note played by a single violin. The ensemble effect is produced by the resulting combination of tones of nominally the same but of slightly unequal pitches of the several instruments. The ensemble effect is further enhanced by differences in the tonal quality of the different instruments. Therefore, to reproduce the "warmth" of tone associated with the ensemble effect by a tone synthesizer, it is desirable to create multiple tones which differ slightly both in pitch and in tonal quality.
The generation of tones producing an ensemble effect in electronic musical instruments is well-known. See, for example, U.S. Pat. Nos. 3,347,973; 3,429,978; 3,884,108; and 3,978,755. Each of these patents disclose methods for producing an ensemble effect by generating frequencies which are offset from the true musical frequency. This has been accomplished in such prior art patents by utilizing multiple tone generators. In copending application Ser. No. 644,450, filed Dec. 29, 1975, entitled "Ensemble and Harmonic Generation in a Polyphonic Tone Synthesizer" and filed by the same inventor as the present application, there is described an ensemble system for a polyphonic digital tone synthesizer capable of producing tones which differ in pitch as well as in tonal quality. This is accomplished by providing separate digital tone generators and requires multiple master data sets to be computed to control the waveforms generated by the several tone generators.
SUMMARY OF THE INVENTION
The present invention is directed to apparatus for producing an ensemble effect in a polyphonic tone synthesizer in which the tonal effect of multiple tones is created by a single tone generator which uses a single master data set.
This is accomplished, in brief, by providing a tone generator having a pair of sift registers for storing the same master data set defining equally-spaced points along one cycle of the waveform of a musical tone to be generated. Words are shifted out of the two registers in synchronism by a single clock source at a frequency which is proportional to the desired pitch of the tone being generated. The words are transferred successively out of the two registers to digital analog converting means during repetitive cycles. By having one register either store one word in the data set twice, or store one less than all the words of the master data set, each repetitive cycle produces one additional word delay between the corresponding words of the master data set at the outputs of the two registers. The resulting combined audio signals thus effectively shift in phase by one clock time during each repetitive cycle, thereby producing an ensemble tone which is the composite of two tones that are slightly different in frequency and in harmonic content.
DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference should be made to the accompanying drawings wherein:
FIG. 1 is a schematic block diagram of a preferred embodiment of the invention;
FIG. 2 illustrates the frequency spectra of signals generated by the system of FIG. 1;
FIG. 3 shows a modification to the arrangement shown in FIG. 1;
FIG. 4 shows the frequency spectra of signals generated by the modification of FIG. 3;
FIG. 5 shows a schematic block diagram of a further embodiment of the invention;
FIG. 6 shows the spectra data obtained from the embodiment of FIG. 5;
FIG. 7 shows yet another embodiment of the invention; and
FIG. 8 is an alternative embodiment to that shown in FIG. 5.
DETAILED DESCRIPTION
The preferred embodiment of the present invention is described as an improvement to the polyphonic tone synthesizer described in detail in U.S. Pat. No. 4,085,644 hereby incorporated by reference. However, the principals of the invention can be applied to other types of digital tone generators.
Referring to FIG. 1 in detail, the polyphonic tone synthesizer of the above-identified patent, during a computational phase, loads a main register 34 with a computed master data set. Each word in the master data set has a value corresponding to the relative amplitude of a point on the waveform of the tone to be generated. Typically, 64 values are stored as part of the master data set to define one complete cycle of the waveform to be generated. Once the master data set is computed and stored in the main register 34, all as described in detail in the above-identified patent, the words are shifted in sequence to any one of a plurality of note shift registers, one of which is indicated at 35, there being one note shift register for each tone generator of the polyphonic tone generator. Only one tone generator is shown in FIG. 1. A note select circuit 40 selects which of the note shift registers is connected to the output of the main register 34 during transfer of the master data set to the tone generator. Shifting from the main register 34 to the note shift register 35 is in synchronism with the output of a note clock 37 associated with the selected tone generator by a clock select circuit 42. The note clock 37 is a voltage controlled oscillator whose frequency is set by operation of a selected key on the instrument keyboard to be a multiple of 64 times the fundamental frequency or pitch of the key-selected note. The note clock 37 is controlled in response to keys operated on the keyboard of the instrument in a manner described in the above-identified patent.
Once the 64 words in the main register 34 are transferred to the note shift register 35, a load select circuit 45 transfers the input to the register 35 from the output of the main register 34 to the output of the note shift register 35 to provide an end-around mode in which the words in the note shift register, at the same time they are shifted out of the register, are continuously recirculated back through the shift register at a rate controlled by the note clock 37. As the words are recirculated through the load select circuit 45, they are also applied to the input of a digital-to-analog converter 47 which converts the sequence of digital words to a varying analog voltage which corresponds in frequency and waveform to the tone being generated. This analog voltage is applied as the audio input to a sound system 11. It should be noted that the various select circuits are all controlled by the logic of an executive control in the manner described in the above-identified patent.
To produce the ensemble effect according to the teaching of the present invention, a slave note shift register 104 is added to one or more of the tone generators of the polyphonic tone synthesizer. As shown in FIG. 1, the master data set from the main register 34 is transferred to the slave note register 104 through a load select circuit 102 at the same time the master data set is transferred to the note shift register 35 through load select circuit 45. Shift pulses are applied to the slave note shift register 104 from the note clock 37 through a gate 108. The gate 108 is controlled by a flip-flop 103. The gate 108 is normally open whenever the flip-flop 103 is in its reset state. The flip-flop 103 is set by the overflow pulse from a modulo 64 counter 106 which counts clock pulses from the note clock 37. Thus after 64 shift pulses have been applied to the slave note shift register 104 through the gate 108, the flip-flop 103 is set and the gate 106 is closed. At the same time, the flip-flop 103 opens a gate 105 which passes the next clock pulse from the note clock source 37 to the reset input of the flip-flop 103. Thus for every 65 note clock pulses 37, only 64 pulses are used to shift the slave note shift register 104, the 65th pulse being blocked by the gate 108. As a result, each successive complete end-around shifting cycle of the slave note register 104 is delayed one note clock pulse interval relative to the note shift register 35.
The output words from the slave note shift register 104 are applied to a digital-to-analog converter 107. One of the words of course is applied to the converter 107 for two note clock intervals with each complete shifting cycle of the register 104. In this manner, the waveshape read out from the slave note shift register in effect contains 65 points per recycle period, but the words are read out at the same clock rate as the 64 points per period read out of the note shift register 35. The resulting tone produced by the output of the slave note shift register 104 and digital-to-analog converter 107 has a fundamental frequency or pitch which is 64/65 of that of the fundamental frequency of the tone produced by the output of the note shift register 35 and digital-to-analog converter 47. As a result, the audio signal produced by the output of the slave note shift register differs from the true pitch of the selected key by -26.84 cents. (Note: a difference of 1200 cents corresponds to one octave). This small frequency deviation of the second tone in a two-tone ensemble has been found to be musically effective. It will be evident that providing a different number of points in the master data set will produce other frequency deviations. In general, if the number of words in the master data set is W, then the frequency deviation in cents caused by adding a data point is: ##EQU1##
FIG. 2 illustrates three spectral diagrams of signals generated by the system shown in FIG. 1. The X axis of these three curves are labeled with the harmonic numbers and the Y axis is the relative DB for each of the harmonics of output signals from the analog-to-digital converters. The top spectra in FIG. 2 is derived from a master data set computed from a set of harmonic coefficients all having the same value. The X marks are the spectral components for the signal outputs for the digital-to-analog converter 47. The solid spectral lines are for the signal output for the digital-to-analog converter 107. The middle spectrum is for a set of harmonic coefficients which decrease in value in steps of two DB. In the bottom spectrum, the harmonic coefficient is 0 for all but the fundamental or first harmonic.
In all of the curves of FIG. 2, it is assumed that the repeated 65th value from the slave note shift register 104 was the maximum number in the master data set for each of the three input data sets. FIG. 3 shows a similar set of spectrum curves for the case in which the repeated point was placed as the first point in the master data set. It will be seen that the spectra of the output of the digital-to-analog coverter 107 varied depending upon which of the 65 points is the repeat point. In FIG. 1, the repeated point occurs randomly each time a tone is initiated. In FIG. 4, however, there is shown an arrangement by which the transfer of words in the master data set is always in fixed relationship to the counting of the clock pulses so that the repeated point is always placed as the first point in the master data set.
As described in the above-identified patent, a sync bit is used to load the note shift register. The sync bit allows the first word of a new master data set from the main resister to always be loaded in the note shift register so as to follow immediately the last word in the prior master data set stored in the note shift register. The sync bit allows loading of the note shift register without interruption with the generation of a tone from a previously stored master data set.
A sync bit detector 39 senses when a word having the sync bit stored in the slave note register 104 is shifted out in response to clock pulses from the note clock source 37. The sync bit detector sets the flip-flop 103 closing the gate 108 and interrupting the shifting of the slave note register 104 until the flip-flop 103 is reset. The flip-flop 103 is reset by the next clock from the note clock source 37 through a gate 105, the gate being opened by the flip-flop 103 when it is in the set state.
In an alternative system shown in FIG. 5, the offset tone is generated by eliminating one word during each repetitive cycle of the master data set, rather than repeating one word as in the arrangement of FIG. 1. The effect is to produce a waveshape having 63 points per period as compared to the standard 64 points per period. Using equation 1 above, the resulting offset frequency differs from the true frequency by +27.26 cents. In the arrangement of FIG. 5, the slave note shift register 104 is shifted an additional time during each complete shift cycle. This is accomplished by providing a control flip-flop 115 which is set by a sync bit shifted out of the slave note shift register 104. A clock select circuit 117 normally connects pulses from the note clock 37 to the shift input of the slave note shift register 104. When the control flip-flop 115 is set, it causes the clock select 117 to select pulses from the master clock. The control flip-flop 115 is reset by the next master clock passed by a gate 116 which is opened by the setting of the flip-flop 115. Since the master clock rate is at least 10 times faster than the highest note clock rate, the effect is to skip one word in the output from the slave note shift register 104 between one note clock and the next. FIG. 6 shows the resulting spectral data obtained from the system shown in FIG. 5.
In the system shown in FIGS. 1, 4, and 5, both the note shift register and the slave note shift register store the 64 words of a master data set. However, the ensemble effect of the present invention may also be accomplished by utilizing shift registers which contain different numbers of words. Thus, in FIG. 7 the system is shown in which the slave note shift register 104 contains 65 words. Two word positions in the slave note shift register 104 receive the same word from the master data set. Thus, as shown in FIG. 7, the master data set is transferred from the main register 34 to both the note shift register 35 and slave note shift register 104 through one output of the note select circuit 48 and the respective load select circuits 45 and 102 in the same manner as described above. However, clock pulses from the note clock 37 are applied to the main register 34 through a gate 140 which is controlled by a flip-flop 142. The flip-flop 142 is set to open the gate 140 by the output of the sync bit detector 39 in response to a sync bit on the output of the note shift register 35 following a signal from the executive control indicating that a transfer cycle has been initiated. The output from the flip-flop 142 opens the gate 140 causing the main register 34 to begin shifting words to the load select circuit 145. The output of the flip-flop 142 also causes the load select circuit 45 to interrupt the end-around mode of the note shift register 35 and in turn cause the words from the main register 34 to be inserted into the note shift register 35 with each note clock pulse.
The output of the sync bit detector resets a modulo 65 counter 144 which counts in response to pulses from the note clock 37. After the counter 144 counts to 64, it resets the flip-flop 142 interrupting further shifting of the main register 34 and returning the load select circuit 45 to the end-around mode. The output from the sync bit detector 39 also sets a second control flip-flop 146, the output of which controls the load select circuit 102 to interrupt the end-around mode and cause the output of the main register 34 to be transferred to the input of the slave note shift register 104. The flip-flop 146 is reset by the counter 144 when it reaches a count of 65. It will be noted that the 65th clock pulse does not shift the main register 34 so that the same word on the output of the main register 34 is inserted in the slave note shift register 104 during two successive shifts of the register, thereby causing the same word to be stored in two successive positions in the slave note shift register 104. The 64 words stored in the note shift register 35 and the 65 words stored in the slave note shift register 104 are shifted in synchronism with the note clock pulses to an adder circuit 148, the output of which is applied to the digital-to-analog converter 47 for conversion to the audio tone. The digital adding of the two ensemble tones before conversion to the analog voltage produces the same functional result as using two converters and adding the analog voltages, in the manner described above in connection with FIGS. 1-6. The arrangement shown in FIG. 7 has the advantage that only one set of loading logic is needed for a plurality of tone generators since the loading logic can be time shared with transfers to any of the tone generators of the polyphonic tone generating system. Time sharing is controlled by means of the clock select circuit 37 which selects the appropriate note clock associated with the particular note shift register and slave shift register being loaded from the main register.
It should also be noted that the ensemble effect can be produced in the arrangement of FIG. 7 even though the 65th word transferred to the slave register is not directly derived from the output of the main register 34. Thus, the same control flip-flop 142 may be used to control both the load select circuits 45 and 102. The result is that the 65th word in the slave note shift register 104 will contain whatever word is left over from a previous set of data stored in the slave note shift register or some other random value.
Yet another embodiment is shown in FIG. 8. Slave shift register 104 provides one less word of storage than the note shift register 35, e.g. 63 words stored in the slave note shift register compared to 64 words stored in the note shift register 35. During the transfer operation from the main register 34, the first word transferred to the slave note register 104 is overwritten by the 64th word during the transfer operation. The subsequent transfer of 64 words against 63 words to the respective digital-to-analog converters 47 and 107 produces the same ensemble effect as that described above in connection with FIG. 5.
It will be appreciated that combinations of the several embodiments may be used to produce three ensemble tones rather than two. For example, by combining the arrangement of FIGS. 7 and 8, two slave note shift registers may be provided, one of which contains 63 words and one of which contains 65 words. As these two slave registers are shifted in synchronism with the note shift register 35, the effect is to produce three tones which are slightly different in frequency and harmonic content.
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An ensemble effect is produced in a digital tone generator by providing a master data set of words having values corresponding to the relative amplitudes of equally spaced points along one cycle of the waveform of the audio tone. These values are transferred sequentially during repetitive cycles at a rate proportional to the pitch of the desired musical tone to a digital-to-analog converter for converting the master data set to an audio signal of the desired waveform and pitch. The ensemble effect is produced by transferring the words of the master data set to a second converter at the same pulse rate but having one value deleted or repeated once in the second set. Because the second set :has one less or one extra value in the set, the resulting audio tones from the two sets change phase with each successive cycle of the audio signals.
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CLAIM OF PRIORITY
This application is a Divisional application claiming 35 USC §120 priority to co-pending U.S. patent application Ser. No. 10/330,897, filed on Dec. 24, 2002 now U.S. Pat. No. 7,240,679, and which is a continuation-in-part of a co-pending U.S. patent application Ser. No. 10/261,839, from which priority under 35 U.S.C. §120 is claimed, entitled “Method and Apparatus for Drying Semiconductor Wafer Surfaces Using a Plurality of Inlets and Outlets Held in Close Proximity to the Wafer Surfaces” filed on Sep. 30, 2002 now U.S. Pat. No. 7,234,477. The aforementioned patent application is hereby incorporated by reference.
CROSS REFERENCE TO RELATED PATENTS
This application is related to U.S. Pat. No. 7,198,055, filed on Apr. 3, 2007, entitled “Meniscus, Vacuum, IPA vapor, Drying Manifold.” The aforementioned patent is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to semiconductor wafer cleaning and drying and, more particularly, to apparatuses and techniques for more efficiently removing fluids from wafer surfaces while reducing contamination and decreasing wafer cleaning cost.
2. Description of the Related Art
In the semiconductor chip fabrication process, it is well-known that there is a need to clean and dry a wafer where a fabrication operation has been performed that leaves unwanted residues on the surfaces of wafers. Examples of such a fabrication operation include plasma etching (e.g., tungsten etch back (WEB)) and chemical mechanical polishing (CMP). In CMP, a wafer is placed in a holder which pushes a wafer surface against a rolling conveyor belt. This conveyor belt uses a slurry which consists of chemicals and abrasive materials to cause the polishing. Unfortunately, this process tends to leave an accumulation of slurry particles and residues at the wafer surface. If left on the wafer, the unwanted residual material and particles may cause, among other things, defects such as scratches on the wafer surface and inappropriate interactions between metallization features. In some cases, such defects may cause devices on the wafer to become inoperable. In order to avoid the undue costs of discarding wafers having inoperable devices, it is therefore necessary to clean the wafer adequately yet efficiently after fabrication operations that leave unwanted residues.
After a wafer has been wet cleaned, the wafer must be dried effectively to prevent water or cleaning fluid remnants from leaving residues on the wafer. If the cleaning fluid on the wafer surface is allowed to evaporate, as usually happens when droplets form, residues or contaminants previously dissolved in the cleaning fluid will remain on the wafer surface after evaporation (e.g., and form spots). To prevent evaporation from taking place, the cleaning fluid must be removed as quickly as possible without the formation of droplets on the wafer surface. In an attempt to accomplish this, one of several different drying techniques are employed such as spin drying, IPA, or Marangoni drying. All of these drying techniques utilize some form of a moving liquid/gas interface on a wafer surface which, if properly maintained, results in drying of a wafer surface without the formation of droplets. Unfortunately, if the moving liquid/gas interface breaks down, as often happens with all of the aforementioned drying methods, droplets form and evaporation occurs resulting in contaminants being left on the wafer surface.
The most prevalent drying technique used today is spin rinse drying (SRD). FIG. 1 illustrates movement of cleaning fluids on a wafer 10 during an SRD drying process. In this drying process, a wet wafer is rotated at a high rate by rotation 14 . In SRD, by use of centrifugal force, the water or cleaning fluid used to clean the wafer is pulled from the center of the wafer to the outside of the wafer and finally off of the wafer as shown by fluid directional arrows 16 . As the cleaning fluid is being pulled off of the wafer, a moving liquid/gas interface 12 is created at the center of the wafer and moves to the outside of the wafer (i.e., the circle produced by the moving liquid/gas interface 12 gets larger) as the drying process progresses. In the example of FIG. 1 , the inside area of the circle formed by the moving liquid/gas interface 12 is free from the fluid and the outside area of the circle formed by the moving liquid/gas interface 12 is the cleaning fluid. Therefore, as the drying process continues, the section inside (the dry area) of the moving liquid/gas interface 12 increases while the area (the wet area) outside of the moving liquid/gas interface 12 decreases. As stated previously, if the moving liquid/gas interface 12 breaks down, droplets of the cleaning fluid form on the wafer and contamination may occur due to evaporation of the droplets. As such, it is imperative that droplet formation and the subsequent evaporation be limited to keep contaminants off of the wafer surface. Unfortunately, the present drying methods are only partially successful at the prevention of moving liquid interface breakdown.
In addition, the SRD process has difficulties with drying wafer surfaces that are hydrophobic. Hydrophobic wafer surfaces can be difficult to dry because such surfaces repel water and water based (aqueous) cleaning solutions. Therefore, as the drying process continues and the cleaning fluid is pulled away from the wafer surface, the remaining cleaning fluid (if aqueous based) will be repelled by the wafer surface. As a result, the aqueous cleaning fluid will want the least amount of area to be in contact with the hydrophobic wafer surface. Additionally, the aqueous cleaning solution tends cling to itself as a result of surface tension (i.e., as a result of molecular hydrogen bonding). Therefore, because of the hydrophobic interactions and the surface tension, balls (or droplets) of aqueous cleaning fluid forms in an uncontrolled manner on the hydrophobic wafer surface. This formation of droplets results in the harmful evaporation and the contamination discussed previously. The limitations of the SRD are particularly severe at the center of the wafer, where centrifugal force acting on the droplets is the smallest. Consequently, although the SRD process is presently the most common way of wafer drying, this method can have difficulties reducing formation of cleaning fluid droplets on the wafer surface especially when used on hydrophobic wafer surfaces.
Therefore, there is a need for a method and an apparatus that avoids the prior art by allowing quick and efficient cleaning and drying of a semiconductor wafer, but at the same time reducing the formation of numerous water or cleaning fluid droplets which may cause contamination to deposit on the wafer surface. Such deposits as often occurs today reduce the yield of acceptable wafers and increase the cost of manufacturing semiconductor wafers.
SUMMARY OF THE INVENTION
Broadly speaking, the present invention fills these needs by providing a cleaning and drying apparatus that is capable of removing fluids from wafer surfaces quickly while at the same time reducing wafer contamination. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device or a method. Several inventive embodiments of the present invention are described below.
In one embodiment, a substrate preparation system is provided which includes a drying system where the drying system includes at least one proximity head for drying a substrate. The system also includes a cleaning system for cleaning the substrate.
In another embodiment, a method for processing a substrate is provided. The processing occurs when the substrate is moved between cluster tools. This method includes providing the substrate to a cluster tool, and the cluster tool is configured to move the substrate into a meniscus processing module having at least one proximity head. The proximity head is configured to perform operations including applying a fluid onto a region of a surface of the substrate, such the fluid is continuously flown so as to substantially fill the region between a surface of the proximity head and the surface of the substrate. An operation of removing the fluid from the region by applying a vacuum force through the proximity head is also provided. The applying and removing is operated substantially simultaneously so that the fluid forms a controlled fluid meniscus that remains between the surface of the substrate and the surface of the proximity head when the proximity head is positioned over the substrate. The method can include moving one of the controlled fluid meniscus or the substrate so that the controlled fluid meniscus is caused to contact regions of the surface of the substrate to cause fluid processing of the surface of the substrate when in the meniscus processing module. The method can also include moving the substrate out of the meniscus processing module and into a next module of the of the cluster tool or out of the cluster tool.
In yet another embodiment, a method for cluster processing a substrate is provided. The method includes performing at least one of etching a substrate, planarizing the substrate, megasonically processing the substrate, cleaning the substrate. The method also includes drying of the substrate. The drying includes applying a first fluid onto a first region of a surface of the substrate, applying a second fluid onto a second region of the surface of the substrate, and removing the first fluid and the second fluid from the surface of the substrate. The removing occurs from a third region that substantially surrounds the first region. The second region substantially surrounds at least a portion of the third region, and the applying and the removing being capable of forming a controlled fluid meniscus.
The advantages of the present invention are numerous. Most notably, the apparatuses and methods described herein efficiently dry and clean a semiconductor wafer while reducing fluids and contaminants remaining on a wafer surface. Consequently, wafer processing and production may be increased and higher wafer yields may be achieved due to efficient wafer drying with lower levels of contamination. The present invention enables the improved drying and cleaning through the use of vacuum fluid removal in conjunction with fluid input. The pressures generated on a fluid film at the wafer surface by the aforementioned forces enable optimal removal of fluid at the wafer surface with a significant reduction in remaining contamination as compared with other cleaning and drying techniques.
In addition, the present invention may utilize application of an isopropyl alcohol (IPA) vapor and deionized water towards a wafer surface along with generation of a vacuum near the wafer surface at substantially the same time. This enables both the generation and intelligent control of a meniscus and the reduction of water surface tension along a deionized water interface and therefore enables optimal removal of fluids from the wafer surface without leaving contaminants. The meniscus generated by input of IPA, DIW and output of fluids may be moved along the surface of the wafer to clean and dry the wafer. Therefore, the present invention evacuates fluid from wafer surfaces with extreme effectiveness while substantially reducing contaminant formation due to ineffective drying such as for example, spin drying.
Moreover the present invention also can be incorporated into numerous types of systems to generate wafer processing systems with cluster tools giving the systems multiple types of processing capabilities. By having a system that can conduct different types of wafer processing, wafers can be processed in a more efficient manner. By having different types of cluster tools in the wafer processing system, there may be less time in wafer transport time because the modules/tools are integrated on one system. In addition, there may space savings so less footprint is needed to house the wafer processing apparatuses. Therefore, the present invention may be incorporated into any suitable variety of systems to make wafer processing more efficient and cost effective.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements.
FIG. 1 illustrates movement of cleaning fluids on a wafer during an SRD drying process.
FIG. 2A shows a wafer cleaning and drying system in accordance with one embodiment of the present invention.
FIG. 2B shows an alternate view of the wafer cleaning and drying system in accordance with one embodiment of present invention.
FIG. 2C illustrates a side close-up view of the wafer cleaning and drying system holding a wafer in accordance with one embodiment of the present invention.
FIG. 2D shows another side close-up view of the wafer cleaning and drying system in accordance with one embodiment of the present invention.
FIG. 3A shows a top view illustrating the wafer cleaning and drying system with dual proximity heads in accordance with one embodiment of the present invention.
FIG. 3B illustrates a side view of the wafer cleaning and drying system with dual proximity heads in accordance with one embodiment of the present invention.
FIG. 4A shows a top view of a wafer cleaning and drying system which includes multiple proximity heads for a particular surface of the wafer in accordance with one embodiment of the present invention.
FIG. 4B shows a side view of the wafer cleaning and drying system which includes multiple proximity heads for a particular surface of the wafer in accordance with one embodiment of the present invention.
FIG. 5A shows a top view of a wafer cleaning and drying system with a proximity head in a horizontal configuration which extends across a diameter of the wafer 108 in accordance with one embodiment of the present invention.
FIG. 5B shows a side view of a wafer cleaning and drying system with the proximity heads in a horizontal configuration which extends across a diameter of the wafer in accordance with one embodiment of the present invention.
FIG. 5C shows a top view of a wafer cleaning and drying system with the proximity heads in a horizontal configuration which is configured to clean and/or dry the wafer that is stationary in accordance with one embodiment of the present invention.
FIG. 5D shows a side view of a wafer cleaning and drying system with the proximity heads in a horizontal configuration which is configured to clean and/or dry the wafer that is stationary in accordance with one embodiment of the present invention.
FIG. 5E shows a side view of a wafer cleaning and drying system with the proximity heads in a vertical configuration enabled to clean and/or dry the wafer that is stationary in accordance with one embodiment of the present invention.
FIG. 5F shows an alternate side view of a wafer cleaning and drying system that is shifted 90 degrees from the side view shown in FIG. 5E in accordance with one embodiment of the present invention.
FIG. 5G shows a top view of a wafer cleaning and drying system with a proximity head in a horizontal configuration which extends across a radius of the wafer in accordance with one embodiment of the present invention.
FIG. 5H shows a side view of a wafer cleaning and drying system with the proximity heads and in a horizontal configuration which extends across a radius of the wafer in accordance with one embodiment of the present invention.
FIG. 6A shows a proximity head inlet/outlet orientation that may be utilized to clean and dry the wafer in accordance with one embodiment of the present invention.
FIG. 6B shows another proximity head inlet/outlet orientation that may be utilized to clean and dry the wafer in accordance with one embodiment of the present invention.
FIG. 6C shows a further proximity head inlet/outlet orientation that may be utilized to clean and dry the wafer in accordance with one embodiment of the present invention.
FIG. 6D illustrates a preferable embodiment of a wafer drying process that may be conducted by a proximity head in accordance with one embodiment of the present invention.
FIG. 6E shows another wafer drying process using another source inlet/outlet orientation that may be conducted by a proximity head in accordance with one embodiment of the present invention.
FIG. 6F shows another source inlet and outlet orientation where an additional source outlet may be utilized to input an additional fluid in accordance with one embodiment of the present invention.
FIG. 7A illustrates a proximity head performing a drying operation in accordance with one embodiment of the present invention.
FIG. 7B shows a top view of a portion of a proximity head in accordance with one embodiment of the present invention.
FIG. 7C illustrates a proximity head with angled source inlets performing a drying operation in accordance with one embodiment of the present invention.
FIG. 7D illustrates a proximity head with angled source inlets and angled source outlets performing a drying operation in accordance with one embodiment of the present invention.
FIG. 8A illustrates a side view of the proximity heads for use in a dual wafer surface cleaning and drying system in accordance with one embodiment of the present invention.
FIG. 8B shows the proximity heads in a dual wafer surface cleaning and drying system in accordance with one embodiment of the present invention.
FIG. 9A illustrates a processing window in accordance with one embodiment of the present invention.
FIG. 9B illustrates a substantially circular processing window in accordance with one embodiment of the present invention.
FIG. 9C illustrates a processing window in accordance with one embodiment of the present invention.
FIG. 9D illustrates a processing window in accordance with one embodiment of the present invention.
FIG. 10A shows an exemplary process window with the plurality of source inlets and as well as the plurality of source outlets in accordance with one embodiment of the present invention.
FIG. 10B shows processing regions of a proximity head in accordance with one embodiment of the present invention.
FIG. 11A shows a top view of a proximity head with a substantially rectangular shape in accordance with one embodiment of the present invention.
FIG. 11B illustrates a side view of the proximity head in accordance with one embodiment of present invention.
FIG. 11C shows a rear view of the proximity head in accordance with one embodiment of the present invention.
FIG. 12A shows a proximity head with a partial rectangular and partial circular shape in accordance with one embodiment of the present invention.
FIG. 12B shows a side view of the proximity head with a partial rectangular and partial circular shape in accordance with one embodiment of the present invention.
FIG. 12C shows a back view of the proximity head with a partial rectangular and partial circular shape in accordance with one embodiment of the present invention.
FIG. 13A shows a rectangular proximity head in accordance with one embodiment of the present invention.
FIG. 13B shows a rear view of the proximity head in accordance with one embodiment of the present invention.
FIG. 13C illustrates a side view of the proximity head in accordance with one embodiment of present invention.
FIG. 14A shows a rectangular proximity head in accordance with one embodiment of the present invention.
FIG. 14B shows a rear view of the rectangular proximity head in accordance with one embodiment of the present invention.
FIG. 14C illustrates a side view of the rectangular proximity head in accordance with one embodiment of present invention.
FIG. 15A shows a proximity head in operation according to one embodiment of the present invention.
FIG. 15B illustrates the proximity head as described in FIG. 15A with IPA input in accordance with one embodiment of the present invention.
FIG. 15C shows the proximity head as described in FIG. 15B , but with the IPA flow increased to 24 ml/min in accordance with one embodiment of the present invention.
FIG. 15D shows the proximity head where the fluid meniscus is shown where the wafer is being rotated in accordance with one embodiment of the present invention.
FIG. 15E shows the proximity head where the fluid meniscus is shown where the wafer is being rotated faster than the rotation shown in FIG. 15D in accordance with one embodiment of the present invention.
FIG. 15F shows the proximity head where the IPA flow has been increased as compared to the IPA flow of FIG. 15D in accordance with one embodiment of the present invention.
FIG. 16A shows a top view of a cleaning/drying system in accordance with one embodiment of the present invention.
FIG. 16B shows an alternative view of the cleaning/drying system in accordance with one embodiment of the present invention.
FIG. 17 illustrates a wafer processing system with front end frame assembly with a drying module in accordance with one embodiment of the present invention.
FIG. 18 shows a wafer processing system which has multiple wafer processing tools in accordance with one embodiment of the present invention.
FIG. 19 shows a wafer processing system without the etching module in accordance with one embodiment of the present invention.
FIG. 20 illustrates a wafer processing system which includes a drying module and a cleaning module in accordance with one embodiment of the present invention.
FIG. 21 shows a block diagram of a wafer processing system in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
Inventions for methods of cleaning and/or drying a wafer are disclosed. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be understood, however, by one of ordinary skill in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.
While this invention has been described in terms of several preferred embodiments, it will be appreciated that those skilled in the art upon reading the preceding specifications and studying the drawings will realize various alterations, additions, permutations and equivalents thereof. It is therefore intended that the present invention includes all such alterations, additions, permutations, and equivalents as fall within the true spirit and scope of the invention.
FIGS. 2A through 2D below illustrate embodiments of an exemplary wafer processing system. It should be appreciated that the system is exemplary, and that any other suitable type of configuration that would enable movement of the proximity head(s) into close proximity to the wafer may be utilized. In the embodiments shown, the proximity head(s) may move in a linear fashion from a center portion of the wafer to the edge of the wafer. It should be appreciated that other embodiments may be utilized where the proximity head(s) move in a linear fashion from one edge of the wafer to another diametrically opposite edge of the wafer, or other non-linear movements may be utilized such as, for example, in a radial motion, in a spiral motion, in a zig-zag motion, etc. In addition, in one embodiment, the wafer may be rotated and the proximity head moved in a linear fashion so the proximity head may process all portions of the wafer. It should also be understood that other embodiments may be utilized where the wafer is not rotated but the proximity head is configured to move over the wafer in a fashion that enables processing of all portions of the wafer. In addition, the proximity head and the wafer cleaning and drying system described herein may be utilized to clean and dry any shape and size of substrates such as for example, 200 mm wafers, 300 mm wafers, flat panels, etc. The wafer cleaning and drying system may be utilized for either or both cleaning and drying the wafer depending on the configuration of the system.
FIG. 2A shows a wafer cleaning and drying system 100 in accordance with one embodiment of the present invention. The system 100 includes rollers 102 a , 102 b , and 102 c which may hold and rotate a wafer to enable wafer surfaces to be dried. The system 100 also includes proximity heads 106 a and 106 b that, in one embodiment, are attached to an upper arm 104 a and to a lower arm 104 b respectively. The upper arm 104 a and the lower arm 104 b are part of a proximity head carrier assembly 104 which enables substantially linear movement of the proximity heads 106 a and 106 b along a radius of the wafer.
In one embodiment the proximity head carrier assembly 104 is configured to hold the proximity head 106 a above the wafer and the proximity head 106 b below the wafer in close proximity to the wafer. This may be accomplished by having the upper arm 104 a and the lower arm 104 b be movable in a vertical manner so once the proximity heads are moved horizontally into a location to start wafer processing, the proximity heads 106 a and 106 b can be moved vertically to a position in close proximity to the wafer. The upper arm 104 a and the lower arm 104 b may be configured in any suitable way so the proximity heads 106 a and 106 b can be moved to enable wafer processing as described herein. It should be appreciated that the system 100 may be configured in any suitable manner as long as the proximity head(s) may be moved in close proximity to the wafer to generate and control a meniscus as discussed below in reference to FIGS. 6D through 8B . It should also be understood that close proximity may be any suitable distance from the wafer as long as a meniscus as discussed in further reference to FIG. 6D through 8B may be maintained. In one embodiment, the proximity heads 106 a and 106 b (as well as any other proximity head described herein) may each be moved to between about 0.1 mm to about 10 mm from the wafer to initiate wafer processing operations. In a preferable embodiment, the proximity heads 106 a and 106 b (as well as any other proximity head described herein) may each be moved to between about 0.5 mm to about 4.5 mm from the wafer to initiate wafer processing operations, and in more preferable embodiment, the proximity heads 106 a and 106 b (as well as any other proximity head described herein) may be moved to about 2 mm from the wafer to initiate wafer processing operations.
FIG. 2B shows an alternate view of the wafer cleaning and drying system 100 in accordance with one embodiment of present invention. The system 100 , in one embodiment, has the proximity head carrier assembly 104 that is configured to enable the proximity heads 106 a and 106 b to be moved from the center of the wafer towards the edge of the wafer. It should be appreciated that the proximity head carrier assembly 104 may be movable in any suitable manner that would enable movement of the proximity heads 106 a and 106 b to clean and/or dry the wafer as desired. In one embodiment, the proximity head carrier assembly 104 can be motorized to move the proximity head 106 a and 106 b from the center of the wafer to the edge of the wafer. It should be understood that although the wafer cleaning and drying system 100 is shown with the proximity heads 106 a and 106 b , that any suitable number of proximity heads may be utilized such as, for example, 1, 2, 3, 4, 5, 6, etc. The proximity heads 106 a and/or 106 b of the wafer cleaning and drying system 100 may also be any suitable size or shape as shown by, for example, any of the proximity heads as described herein. The different configurations described herein generate a fluid meniscus between the proximity head and the wafer. The fluid meniscus may be moved across the wafer to clean and dry the wafer by applying fluid to the wafer surface and removing the fluids from the surface. Therefore, the proximity heads 106 a and 106 b can have any numerous types of configurations as shown herein or other configurations that enable the processes described herein. It should also be appreciated that the system 100 may clean and dry one surface of the wafer or both the top surface and the bottom surface of the wafer.
In addition, besides cleaning or drying both the top and bottom surfaces and of the wafer, the system 100 may also be configured to clean one side of the wafer and dry another side of the wafer if desired by inputting and outputting different types of fluids. It should be appreciated that the system 100 may utilize the application of different chemicals top and bottom in the proximity heads 106 a and 106 b respectively depending on the operation desired. The proximity heads can be configured to clean and dry the bevel edge of the wafer in addition to cleaning and/or drying the top and/or bottom of the wafer. This can be accomplished by moving the meniscus off the edge the wafer which cleans the bevel edge. It should also be understood that the proximity heads 106 a and 106 b may be the same type of apparatus or different types of proximity heads.
FIG. 2C illustrates a side close-up view of the wafer cleaning and drying system 100 holding a wafer 108 in accordance with one embodiment of the present invention. The wafer 108 may be held and rotated by the rollers 102 a , 102 b , and 102 c in any suitable orientation as long as the orientation enables a desired proximity head to be in close proximity to a portion of the wafer 108 that is to be cleaned or dried. In one embodiment, the roller 102 b may be rotated by using a spindle 111 , and the roller 102 c may held and rotated by a roller arm 109 . The roller 102 a may also be rotated by its own spindle (as shown in FIG. 3B . In one embodiment, the rollers 102 a , 102 b , and 102 c can rotate in a clockwise direction to rotate the wafer 108 in a counterclockwise direction. It should be understood that the rollers may be rotated in either a clockwise or a counterclockwise direction depending on the wafer rotation desired. In one embodiment, the rotation imparted on the wafer 108 by the rollers 102 a , 102 b , and 102 c serves to move a wafer area that has not been processed into close proximity to the proximity heads 106 a and 106 b . However, the rotation itself does not dry the wafer or move fluid on the wafer surfaces towards the edge of the wafer. Therefore, in an exemplary drying operation, the wet areas of the wafer would be presented to the proximity heads 106 a and 106 b through both the linear motion of the proximity heads 106 a and 106 b and through the rotation of the wafer 108 . The drying or cleaning operation itself is conducted by at least one of the proximity heads. Consequently, in one embodiment, a dry area of the wafer 108 would expand from a center region to the edge region of the wafer 108 in a spiral movement as a drying operation progresses. In a preferable embodiment, the dry are of the wafer 108 would move around the wafer 108 and the wafer 108 would be dry in one rotation (if the length of the proximity heads 106 a and 106 b are at least a radius of the wafer 108 ) By changing the configuration of the system 100 and the orientation of and movement of the proximity head 106 a and/or the proximity head 106 b , the drying movement may be changed to accommodate nearly any suitable type of drying path.
It should be understood that the proximity heads 106 a and 106 b may be configured to have at least one of first source inlet configured to input deionized water (DIW) (also known as a DIW inlet), at least one of a second source inlet configured to input isopropyl alcohol (IPA) in vapor form (also known as IPA inlet), and at least one source outlet configured to output fluids from a region between the wafer and a particular proximity head by applying vacuum (also known as vacuum outlet). It should be appreciated that the vacuum utilized herein may also be suction. In addition, other types of solutions may be inputted into the first source inlet and the second source inlet such as, for example, cleaning solutions, ammonia, HF, etc. It should be appreciated that although IPA vapor is used in some of the exemplary embodiments, any other type of vapor may be utilized such as for example, nitrogen, any suitable alcohol vapor, organic compounds, etc. that may be miscible with water.
In one embodiment, the at least one IPA vapor inlet is adjacent to the at least one vacuum outlet which is in turn adjacent to the at least one DIW inlet to form an IPA-vacuum-DIW orientation. It should be appreciated that other types of orientations such as IPA-DIW-vacuum, DIW-vacuum-IPA, vacuum-IPA-DIW, etc. may be utilized depending on the wafer processes desired and what type of wafer cleaning and drying mechanism is sought to be enhanced. In a preferable embodiment, the IPA-vacuum-DIW orientation may be utilized to intelligently and powerfully generate, control, and move the meniscus located between a proximity head and a wafer to clean and dry wafers. The DIW inlets, the IPA vapor inlets, and the vacuum outlets may be arranged in any suitable manner if the above orientation is maintained. For example, in addition to the IPA vapor inlet, the vacuum outlet, and the DIW inlet, in an additional embodiment, there may be additional sets of IPA vapor outlets, DIW inlets and/or vacuum outlets depending on the configuration of the proximity head desired. Therefore, another embodiment may utilize an IPA-vacuum-DIW-DIW-vacuum-IPA or other exemplary embodiments with an IPA source inlet, vacuum source outlet, and DIW source inlet configurations are described herein with a preferable embodiment being described in reference to FIG. 6D . It should be appreciated that the exact configuration of the IPA-vacuum-DIW orientation may be varied depending on the application. For example, the distance between the IPA input, vacuum, and DIW input locations may be varied so the distances are consistent or so the distances are inconsistent. In addition, the distances between the IPA input, vacuum, and DIW output may differ in magnitude depending on the size, shape, and configuration of the proximity head 106 a and the desired size of a process window as described in further detail in reference to FIG. 10 . In addition, as discussed in reference to FIG. 10 , the IPA-vacuum-DIW orientation is configured so a vacuum region substantially surrounds a DIW region and the IPA region substantially surrounds at least the trailing edge region of the vacuum region.
FIG. 2D shows another side close-up view of the wafer cleaning and drying system 100 in accordance with one embodiment of the present invention. In this embodiment, the proximity heads 106 a and 106 b have been positioned in close proximity to a top surface 108 a and a bottom surface 108 b of the wafer 108 respectively by utilization of the proximity head carrier assembly 104 . Once in this position, the proximity heads 106 a and 106 b may utilize the IPA and DIW source inlets and a vacuum source outlet(s) to generate wafer processing meniscuses in contact with the wafer 108 which are capable of removing fluids from a top surface 108 a and a bottom surface 108 b . The wafer processing meniscus may be generated in accordance with the descriptions in reference to FIGS. 6 through 9B where IPA vapor and DIW are inputted into the region between the wafer 108 and the proximity heads 106 a and 106 b . At substantially the same time the IPA and DIW is inputted, a vacuum may be applied in close proximity to the wafer surface to output the IPA vapor, the DIW, and the fluids that may be on a wafer surface. It should be appreciated that although IPA is utilized in the exemplary embodiment, any other suitable type of vapor may be utilized such as for example, nitrogen, any suitable alcohol vapor, organic compounds, hexanol, ethyl glycol; etc. that may be miscible with water. The portion of the DIW that is in the region between the proximity head and the wafer is the meniscus. It should be appreciated that as used herein, the term “output” can refer to the removal of fluid from a region between the wafer 108 and a particular proximity head, and the term “input” can be the introduction of fluid to the region between the wafer 108 and the particular proximity head.
In another exemplary embodiment, the proximity heads 106 a and 106 b may be moved in a manner so all parts of the wafer 108 are cleaned, dried, or both without the wafer 108 being rotated. In such an embodiment, the proximity head carrier assembly 104 may be configured to enable movement of the either one or both of the proximity heads 106 a and 106 b to close proximity of any suitable region of the wafer 108 . In one embodiment, of the proximity heads are smaller in length than a radius of the wafer, the proximity heads may be configured to move in a spiral manner from the center to the edge of the wafer 108 or vice versa. In a preferable embodiment, when the proximity heads are larger in length than a radius of the wafer, the proximity heads 106 a and 106 b may be moved over the entire surface of the wafer in one rotation. In another embodiment, the proximity heads 104 a and 104 b may be configured to move in a linear fashion back and forth across the wafer 108 so all parts of the wafer surfaces 108 a and/or 108 b may be processed. In yet another embodiment, configurations as discussed below in reference to FIG. 5C through 5H may be utilized. Consequently, countless different configurations of the system 100 may be utilized in order to obtain an optimization of the wafer processing operation.
FIG. 3A shows a top view illustrating the wafer cleaning and drying system 100 with dual proximity heads in accordance with one embodiment of the present invention. As described above in reference to FIGS. 2A to 2D , the upper arm 104 a may be configured to move and hold the proximity head 106 a in a position in close proximity over the wafer 108 . The upper arm 104 a may also be configured to move the proximity head 106 a from a center portion of the wafer 108 towards the edge of the wafer 108 in a substantially linear fashion 113 . Consequently, in one embodiment, as the wafer 108 moves as shown by rotation 112 , the proximity head 106 a is capable of removing a fluid film from the top surface 108 a of the wafer 108 using a process described in further detail in reference to FIGS. 6 through 8 . Therefore, the proximity head 106 a may dry the wafer 108 in a substantially spiral path over the wafer 108 . In another embodiment as shown in reference to FIG. 3B , there may be a second proximity head located below the wafer 108 to remove a fluid film from the bottom surface 108 b of the wafer 108 .
FIG. 3B illustrates a side view of the wafer cleaning and drying system 100 with dual proximity heads in accordance with one embodiment of the present invention. In this embodiment, the system 100 includes both the proximity head 106 a capable of processing a top surface of the wafer 108 and the proximity head 106 b capable of processing a bottom surface of the wafer 108 . In one embodiment, spindles 111 a and 111 b along with a roller arm 109 may rotate the rollers 102 a , 102 b , and 102 c respectively. This rotation of the rollers 102 a , 102 b , and 102 c may rotate the wafer 108 so substantially all surfaces of the wafer 108 may be presented to the proximity heads 106 a and 106 b for drying and/or cleaning. In one embodiment, while the wafer 108 is being rotated, the proximity heads 106 a and 106 b are brought to close proximity of the wafer surfaces 108 a and 108 b by the arms 104 a and 104 b respectively. Once the proximity heads 106 a and 106 b are brought into close proximity to the wafer 108 , the wafer drying or cleaning may be begun. In operation, the proximity heads 106 a and 106 b may each remove fluids from the wafer 108 by applying IPA, deionized water and vacuum to the top surface and the bottom surface of the wafer 108 as described in reference to FIG. 6 .
In one embodiment, by using the proximity heads 106 a and 106 b , the system 100 may dry a 200 mm wafer in less than 45 seconds. In another embodiment, where the proximity heads 106 a and 106 b are at least a radius of the wafer in length, the drying time for a wafer may be less than 30 seconds. It should be understood that drying or cleaning time may be decreased by increasing the speed at which the proximity heads 106 a and 106 b travels from the center of the wafer 108 to the edge of the wafer 108 . In another embodiment, the proximity heads 106 a and 106 b may be utilized with a faster wafer rotation to dry the wafer 108 in less time. In yet another embodiment, the rotation of the wafer 108 and the movement of the proximity heads 106 a and 106 b may be adjusted in conjunction to obtain an optimal drying/cleaning speed. In one embodiment, the proximity heads 106 a and 106 b may move linearly from a center region of the wafer 108 to the edge of the wafer 108 at between about 0 mm per second to about 50 mm per second.
FIG. 4A shows a top view of a wafer cleaning and drying system 100 - 1 which includes multiple proximity heads for a particular surface of the wafer 108 in accordance with one embodiment of the present invention. In this embodiment, the system 100 - 1 includes an upper arm 104 a - 1 and an upper arm 104 a - 2 . As shown in FIG. 4B , the system 100 - 1 also may include lower arm 104 b - 1 and lower arm 104 b - 2 connected to proximity heads 106 b - 1 and 106 b - 2 respectively. In the system 100 - 1 , the proximity heads 106 a - 1 and 106 a - 2 (as well as 106 b - 1 and 106 b - 2 if top and bottom surface processing is being conducted) work in conjunction so, by having two proximity heads processing a particular surface of the wafer 108 , drying time or cleaning time may be cut to about half of the time. Therefore, in operation, while the wafer 108 is rotated, the proximity heads 106 a - 1 , 106 a - 2 , 106 b - 1 , and 106 b - 2 start processing the wafer 108 near the center of the wafer 108 and move outward toward the edge of the wafer 108 in a substantially linear fashion. In this way, as the rotation 112 of the wafer 108 brings all regions of the wafer 108 in proximity with the proximity heads so as to process all parts of the wafer 108 . Therefore, with the linear movement of the proximity heads 106 a - 1 , 106 a - 2 , 106 b - 1 , and 106 b - 2 and the rotational movement of the wafer 108 , the wafer surface being dried moves in a spiral fashion from the center of the wafer 108 to the edge of the wafer 108 .
In another embodiment, the proximity heads 106 a - 1 and 106 b - 1 may start processing the wafer 108 and after they have moved away from the center region of the wafer 108 , the proximity heads 106 a - 2 and 106 b - 2 may be moved into place in the center region of the wafer 108 to augment in wafer processing operations. Therefore, the wafer processing time may be decreased significantly by using multiple proximity heads to process a particular wafer surface.
FIG. 4B shows a side view of the wafer cleaning and drying system 100 - 1 which includes multiple proximity heads for a particular surface of the wafer 108 in accordance with one embodiment of the present invention. In this embodiment, the system 100 - 1 includes both the proximity heads 106 a - 1 and 106 a - 2 that are capable of processing the top surface 108 a of the wafer 108 , and proximity heads 106 b - 1 and 106 b - 2 capable of processing the bottom surface 108 b of the wafer 108 . As in the system 100 , the spindles 111 a and 111 b along with a roller arm 109 may rotate the rollers 102 a , 102 b , and 102 c respectively. This rotation of the rollers 102 a , 102 b , and 102 c may rotate the wafer 108 so substantially all surfaces of the wafer 108 may brought in close proximity to the proximity heads 106 a - 1 , 106 a - 2 , 106 b - 1 , and 106 b - 2 for wafer processing operations.
In operation, each of the proximity heads 106 a - 1 , 106 a - 2 , 106 b - 1 , and 106 b - 2 may remove fluids from the wafer 108 by applying IPA, deionized water and vacuum to the top surface and the bottom surface of the wafer 108 as shown, for example, in FIG. 6 through 8 . By having two proximity heads per wafer side, the wafer processing operation (i.e., cleaning and/or drying) may be accomplished in substantially less time. It should be appreciated that as with the wafer processing system described in reference to FIGS. 3A and 3B , the speed of the wafer rotation may be varied to any suitable speed as long as the configuration enables proper wafer processing. In one embodiment, the wafer processing time may be decreased when half a rotation of the wafer 108 is used to dry the entire wafer. In such an embodiment, the wafer processing speed may be about half of the processing speed when only one proximity head is utilized per wafer side.
FIG. 5A shows a top view of a wafer cleaning and drying system 100 - 2 with a proximity head 106 a - 3 in a horizontal configuration which extends across a diameter of the wafer 108 in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 a - 3 is held by an upper arm 104 a - 3 that extends across a diameter of the wafer 108 . In this embodiment, the proximity head 106 a - 3 may be moved into a cleaning/drying position by a vertical movement of the upper arm 104 a - 3 so the proximity head 106 a - 3 can be in a position that is in close proximity to the wafer 108 . Once the proximity head 106 a - 3 is in close proximity to the wafer 108 , the wafer processing operation of a top surface of the wafer 108 can take place.
FIG. 5B shows a side view of a wafer cleaning and drying system 100 - 2 with the proximity heads 106 a - 3 and 106 b - 3 in a horizontal configuration which extends across a diameter of the wafer 108 in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 a - 3 and the proximity head 106 b - 3 both are elongated to be able to span the diameter of the wafer 108 . In one embodiment, while the wafer 108 is being rotated, the proximity heads 106 a - 3 and 106 b - 3 are brought to close proximity of the wafer surfaces 108 a and 108 b by the top arm 104 a and a bottom arm 106 b - 3 respectively. Because the proximity heads 106 a - 3 and 106 b - 3 extend across the wafer 108 , only half of a full rotation may be needed to clean/dry the wafer 108 .
FIG. 5C shows a top view of a wafer cleaning and drying system 100 - 3 with the proximity heads 106 a - 3 and 106 b - 3 in a horizontal configuration which is configured to clean and/or dry the wafer 108 that is stationary in accordance with one embodiment of the present invention. In this embodiment, the wafer 108 may be held stationary by any suitable type of wafer holding device such as, for example, an edge grip, fingers with edge attachments, etc. The proximity head carrier assembly 104 ′″ is configured to be movable from one edge of the wafer 108 across the diameter of the wafer 108 to an edge on the other side of the wafer 108 after crossing the entire wafer diameter. In this fashion, the proximity head 106 a - 3 and/or the proximity head 106 b - 3 (as shown below in reference to FIG. 5D ) may move across the wafer following a path along a diameter of the wafer 108 from one edge to an opposite edge. It should be appreciated that the proximity heads 106 a - 3 and/or 106 b - 3 may be move from any suitable manner that would enable moving from one edge of the wafer 108 to another diametrically opposite edge. In one embodiment, the proximity head 106 a - 3 and/or the proximity head 106 b - 3 may move in directions 121 (e.g., top to bottom or bottom to top of FIG. 5C ). Therefore, the wafer 108 may stay stationary without any rotation or movement and the proximity heads 106 a - 3 and/or the proximity head 106 b - 3 may move into close proximity of the wafer and, through one pass over the wafer 108 , clean/dry the top and/or bottom surface of the wafer 108 .
FIG. 5D shows a side view of a wafer cleaning and drying system 100 - 3 with the proximity heads 106 a - 3 and 106 b - 3 in a horizontal configuration which is configured to clean and/or dry the wafer 108 that is stationary in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 a - 3 is in a horizontal position with the wafer 108 also in a horizontal position. By use of the proximity head 106 a - 3 and the proximity head 106 b - 3 that spans at least the diameter of the wafer 108 , the wafer 108 may be cleaned and/or dried in one pass by moving proximity heads 106 a - 3 and 106 b - 3 in the direction 121 as discussed in reference to FIG. 5C .
FIG. 5E shows a side view of a wafer cleaning and drying system 100 - 4 with the proximity heads 106 a - 3 and 106 b - 3 in a vertical configuration enabled to clean and/or dry the wafer 108 that is stationary in accordance with one embodiment of the present invention. In this embodiment, the proximity heads 106 a - 3 and 106 b - 3 are in a vertical configuration, and the proximity heads 106 a - 3 and 106 b - 3 are configured to move either from left to right, or from right to left, beginning from a first edge of the wafer 108 to a second edge of the wafer 108 that is diametrically opposite to the first edge. Therefore, in such as embodiment, the proximity head carrier assembly 104 ′″ may move the proximity heads 104 a - 3 and 104 b - 3 in close proximity with the wafer 108 and also enable the movement of the proximity heads 104 a - 3 and 104 b - 3 across the wafer from one edge to another so the wafer 108 may be processed in one pass thereby decreasing the time to clean and/or dry the wafer 108 .
FIG. 5F shows an alternate side view of a wafer cleaning and drying system 100 - 4 that is shifted 90 degrees from the side view shown in FIG. 5E in accordance with one embodiment of the present invention. It should be appreciated that the proximity head carrier assembly 104 ′″ may be oriented in any suitable manner such as for example, having the proximity head carrier assembly 104 ′″ rotated 180 degrees as compared with what is shown in FIG. 5F .
FIG. 5G shows a top view of a wafer cleaning and drying system 100 - 5 with a proximity head 106 a - 4 in a horizontal configuration which extends across a radius of the wafer 108 in accordance with one embodiment of the present invention. In one embodiment, the proximity head 106 a - 4 extends across less than a radius of a substrate being processed. In another embodiment, the proximity head 106 a - 4 may extend the radius of the substrate being processed. In a preferable embodiment, the proximity head 106 a - 4 extends over a radius of the wafer 108 so the proximity head may process both the center point of the wafer 108 as well as an edge of the wafer 108 so the proximity head 106 a - 4 can cover and process the center point of the wafer and the edge of the wafer. In this embodiment, the proximity head 106 a - 4 may be moved into a cleaning/drying position by a vertical movement of the upper arm 104 a - 4 so the proximity head 106 a - 4 can be in a position that is in close proximity to the wafer 108 . Once the proximity head 106 a - 4 is in close proximity to the wafer 108 , the wafer processing operation of a top surface of the wafer 108 can take place. Because, in one embodiment, the proximity head 106 a - 4 extends over the radius of the wafer, the wafer may be cleaned and/or dried in one rotation.
FIG. 5H shows a side view of a wafer cleaning and drying system 100 - 5 with the proximity heads 106 a - 4 and 106 b - 4 in a horizontal configuration which extends across a radius of the wafer 108 in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 a - 4 and the proximity head 106 b - 4 both are elongated to be able to extend over and beyond the radius of the wafer 108 . As discussed in reference to FIG. 5G , depending on the embodiment desired, the proximity head 106 a - 4 may extend less than a radius, exactly a radius, or greater than a radius of the wafer 108 . In one embodiment, while the wafer 108 is being rotated, the proximity heads 106 a - 4 and 106 b - 4 are brought to close proximity of the wafer surfaces 108 a and 108 b by the top arm 104 a and a bottom arm 106 b - 4 respectively. Because in one embodiment, the proximity heads 106 a - 4 and 106 b - 4 extend across greater than the radius of the wafer 108 , only a full rotation may be needed to clean/dry the wafer 108 .
It should be understood that any of the systems 100 , 100 - 1 , 100 - 2 , 100 - 3 , 100 - 4 , 100 - 5 , and any suitable variant thereof, may be utilized as a cluster tool within a wafer processing system. A cluster tool is an apparatus that may be incorporated into a frame assembly (such as those discussed in further detail in reference to FIGS. 17 through 21 below with other wafer processing equipment so multiple wafers and/or multiple types of wafer processing may be conducted in one system.
FIG. 6A shows a proximity head inlet/outlet orientation 117 that may be utilized to clean and dry the wafer 108 in accordance with one embodiment of the present invention. In one embodiment, the orientation 117 is a portion of a proximity head 106 a where other source inlets 302 and 306 in addition to other source outlets 304 may be utilized in addition to the orientation 117 shown. The orientation 117 may include a source inlet 306 on a leading edge 109 with a source outlet 304 in between the source inlet 306 and the source outlet 302 .
FIG. 6B shows another proximity head inlet/outlet orientation 119 that may be utilized to clean and dry the wafer 108 in accordance with one embodiment of the present invention. In one embodiment, the orientation 119 is a portion of a proximity head 106 a where other source inlets 302 and 306 in addition to other source outlets 304 may be utilized in addition to the orientation 119 shown. The orientation 119 may include a source outlet 304 on a leading edge 109 with a source inlet 302 in between the source outlet 304 and the source inlet 306 .
FIG. 6C shows a further proximity head inlet/outlet orientation 121 that may be utilized to clean and dry the wafer 108 in accordance with one embodiment of the present invention. In one embodiment, the orientation 121 is a portion of a proximity head 106 a where other source inlets 302 and 306 in addition to other source outlets 304 may be utilized in addition to the orientation 119 shown. The orientation 119 may include a source inlet 306 on a leading edge 109 with a source inlet 302 in between the source outlet 304 and the source outlet 306 .
FIG. 6D illustrates a preferable embodiment of a wafer drying process that may be conducted by a proximity head 106 a in accordance with one embodiment of the present invention. Although FIG. 6 shows a top surface 108 a being dried, it should be appreciated that the wafer drying process may be accomplished in substantially the same way for the bottom surface 108 b of the wafer 108 . In one embodiment, a source inlet 302 may be utilized to apply isopropyl alcohol (IPA) vapor toward a top surface 108 a of the wafer 108 , and a source inlet 306 may be utilized to apply deionized water (DIW) toward the top surface 108 a of the wafer 108 . In addition, a source outlet 304 may be utilized to apply vacuum to a region in close proximity to the wafer surface to remove fluid or vapor that may located on or near the top surface 108 a . It should be appreciated that any suitable combination of source inlets and source outlets may be utilized as long as at least one combination exists where at least one of the source inlet 302 is adjacent to at least one of the source outlet 304 which is in turn adjacent to at least one of the source inlet 306 . The IPA may be in any suitable form such as, for example, IPA vapor where IPA in vapor form is inputted through use of a N 2 gas. Moreover, although DIW is utilized herein, any other suitable fluid may be utilized that may enable or enhance the wafer processing such as, for example, water purified in other ways, cleaning fluids, etc. In one embodiment, an IPA inflow 310 is provided through the source inlet 302 , a vacuum 312 may be applied through the source outlet 304 and DIW inflow 314 may be provided through the source inlet 306 . Therefore, an embodiment of the IPA-vacuum-DIW orientation as described above in reference to FIG. 2 is utilized. Consequently, if a fluid film resides on the wafer 108 , a first fluid pressure may be applied to the wafer surface by the IPA inflow 310 , a second fluid pressure may be applied to the wafer surface by the DIW inflow 314 , and a third fluid pressure may be applied by the vacuum 312 to remove the DIW, IPA and the fluid film on the wafer surface.
Therefore, in one embodiment, as the DIW inflow 314 and the IPA inflow 310 is applied toward a wafer surface, any fluid on the wafer surface is intermixed with the DIW inflow 314 . At this time, the DIW inflow 314 that is applied toward the wafer surface encounters the IPA inflow 310 . The IPA forms an interface 118 (also known as an IPA/DIW interface 118 ) with the DIW inflow 314 and along with the vacuum 312 assists in the removal of the DIW inflow 314 along with any other fluid from the surface of the wafer 108 . In one embodiment, the IPA/DIW interface 118 reduces the surface of tension of the DIW. In operation, the DIW is applied toward the wafer surface and almost immediately removed along with fluid on the wafer surface by the vacuum applied by the source outlet 304 . The DIW that is applied toward the wafer surface and for a moment resides in the region between a proximity head and the wafer surface along with any fluid on the wafer surface forms a meniscus 116 where the borders of the meniscus 116 are the IPA/DIW interfaces 118 . Therefore, the meniscus 116 is a constant flow of fluid being applied toward the surface and being removed at substantially the same time with any fluid on the wafer surface. The nearly immediate removal of the DIW from the wafer surface prevents the formation of fluid droplets on the region of the wafer surface being dried thereby reducing the possibility of contamination drying on the wafer 108 . The pressure (which is caused by the flow rate of the IPA) of the downward injection of IPA also helps contain the meniscus 116 .
The flow rate of the IPA assists in causing a shift or a push of water flow out of the region between the proximity head and the wafer surface and into the source outlets 304 through which the fluids may be outputted from the proximity head. Therefore, as the IPA and the DIW is pulled into the source outlets 304 , the boundary making up the IPA/DIW interface 118 is not a continuous boundary because gas (e.g., air) is being pulled into the source outlets 304 along with the fluids. In one embodiment, as the vacuum from the source outlet 304 pulls the DIW, IPA, and the fluid on the wafer surface, the flow into the source outlet 304 is discontinuous. This flow discontinuity is analogous to fluid and gas being pulled up through a straw when a vacuum is exerted on combination of fluid and gas. Consequently, as the proximity head 106 a moves, the meniscus moves along with the proximity head, and the region previously occupied by the meniscus has been dried due to the movement of the IPA/DIW interface 118 . It should also be understood that the any suitable number of source inlets 302 , source outlets 304 and source inlets 306 may be utilized depending on the configuration of the apparatus and the meniscus size and shape desired. In another embodiment, the liquid flow rates and the vacuum flow rates are such that the total liquid flow into the vacuum outlet is continuous, so no gas flows into the vacuum outlet.
It should be appreciated any suitable flow rate may be utilized for the IPA, DIW, and vacuum as long as the meniscus 116 can be maintained. In one embodiment, the flow rate of the DIW through a set of the source inlets 306 is between about 25 ml per minute to about 3,000 ml per minute. In a preferable embodiment, the flow rate of the DIW through the set of the source inlets 306 is about 400 ml per minute. It should be understood that the flow rate of fluids may vary depending on the size of the proximity head. In one embodiment a larger head may have a greater rate of fluid flow than smaller proximity heads. This may occur because larger proximity heads, in one embodiment, have more source inlets 302 and 306 and source outlets 304 More flow for larger head.
In one embodiment, the flow rate of the IPA vapor through a set of the source inlets 302 is between about 1 standard cubic feet per hour (SCFH) to about 100 SCFH. In a preferable embodiment, the IPA flow rate is between about 5 and 50 SCFM.
In one embodiment, the flow rate for the vacuum through a set of the source outlets 304 is between about 10 standard cubic feet per hour (SCFH) to about 1250 SCFH. In a preferable embodiment, the flow rate for a vacuum though the set of the source outlets 304 is about 350 SCFH. In an exemplary embodiment, a flow meter may be utilized to measure the flow rate of the IPA, DIW, and the vacuum.
FIG. 6E shows another wafer drying process using another source inlet/outlet orientation that may be conducted by a proximity head 106 a in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 a may be moved over the top surface 108 a of the wafer 108 so the meniscus may be moved along the wafer surface 108 a . The meniscus applies fluid to the wafer surface and removes fluid from the wafer surface thereby cleaning and drying the wafer simultaneously. In this embodiment, the source inlet 306 applies a DIW flow 314 toward the wafer surface 108 a , the source inlet 302 applies IPA flow 310 toward the wafer surface 108 a , and the source outlet 312 removes fluid from the wafer surface 108 a . It should be appreciated that in this embodiment as well as other embodiments of the proximity head 106 a described herein, additional numbers and types of source inlets and source outlets may be used in conjunction with the orientation of the source inlets 302 and 306 and the source outlets 304 shown in FIG. 6E . In addition, in this embodiment as well as other proximity head embodiments, by controlling the amount of flow of fluids onto the wafer surface 108 a and by controlling the vacuum applied, the meniscus may be managed and controlled in any suitable manner. For example, in one embodiment, by increasing the DIW flow 314 and/or decreasing the vacuum 312 , the outflow through the source outlet 304 may be nearly all DIW and the fluids being removed from the wafer surface 108 a . In another embodiment, by decreasing the DIW flow 314 and/or increasing the vacuum 312 , the outflow through the source outlet 304 may be substantially a combination of DIW and air as well as fluids being removed from the wafer surface 108 a.
FIG. 6F shows another source inlet and outlet orientation where an additional source outlet 307 may be utilized to input an additional fluid in accordance with one embodiment of the present invention. The orientation of inlets and outlets as shown in FIG. 6E is the orientation described in further detail in reference to FIG. 6D except the additional source outlet 307 is included adjacent to the source inlet 306 on a side opposite that of the source outlet 304 . In such an embodiment, DIW may be inputted through the source inlet 306 while a different solution such as, for example, a cleaning solution may be inputted through the source inlet 307 . Therefore, a cleaning solution flow 315 may be utilized to enhance cleaning of the wafer 108 while at substantially the same time drying the top surface 108 a of the wafer 108 .
FIG. 7A illustrates a proximity head 106 performing a drying operation in accordance with one embodiment of the present invention. The proximity head 106 , in one embodiment, moves while in close proximity to the top surface 108 a of the wafer 108 to conduct a cleaning and/or drying operation. It should be appreciated that the proximity head 106 may also be utilized to process (e.g., clean, dry, etc.) the bottom surface 108 b of the wafer 108 . In one embodiment, the wafer 108 is rotating so the proximity head 106 may be moved in a linear fashion along the head motion while fluid is removed from the top surface 108 a . By applying the IPA 310 through the source inlet 302 , the vacuum 312 through source outlet 304 , and the deionized water 314 through the source inlet 306 , the meniscus 116 as discussed in reference to FIG. 6 may be generated.
FIG. 7B shows a top view of a portion of a proximity head 106 in accordance with one embodiment of the present invention. In the top view of one embodiment, from left to right are a set of the source inlet 302 , a set of the source outlet 304 , a set of the source inlet 306 , a set of the source outlet 304 , and a set of the source inlet 302 . Therefore, as IPA and DIW are inputted into the region between the proximity head 106 and the wafer 108 , the vacuum removes the IPA and the DIW along with any fluid film that may reside on the wafer 108 . The source inlets 302 , the source inlets 306 , and the source outlets 304 described herein may also be any suitable type of geometry such as for example, circular opening, square opening, etc. In one embodiment, the source inlets 302 and 306 and the source outlets 304 have circular openings.
FIG. 7C illustrates a proximity head 106 with angled source inlets 302 ′ performing a drying operation in accordance with one embodiment of the present invention. It should be appreciated that the source inlets 302 ′ and 306 and the source outlet(s) 304 described herein may be angled in any suitable way to optimize the wafer cleaning and/or drying process. In one embodiment, the angled source inlets 302 ′ that input IPA vapor onto the wafer 108 is angled toward the source inlets 306 such that the IPA vapor flow is directed to contain the meniscus 116 .
FIG. 7D illustrates a proximity head 106 with angled source inlets 302 ′ and angled source outlets 304 ′ performing a drying operation in accordance with one embodiment of the present invention. It should be appreciated that the source inlets 302 ′ and 306 and the angled source outlet(s) 304 ′ described herein may be angled in any suitable way to optimize the wafer cleaning and/or drying process.
In one embodiment, the angled source inlets 302 ′ that input IPA vapor onto the wafer 108 is angled at an angle θ 500 toward the source inlets 306 such that the IPA vapor flow is directed to contain the meniscus 116 . The angled source outlet 304 ′ may, in one embodiment, be angled at an angle θ 500 towards the meniscus 116 . It should be appreciated that the angle θ 500 and the angle θ 502 may be any suitable angle that would optimize the management and control of the meniscus 116 . In one embodiment, the angle θ 500 is greater than 0 degrees and less than 90 degrees, and the angle θ 502 is greater than 0 degrees and less than 90 degrees. In a preferable embodiment, the angle θ 500 is about 15 degrees, and in another preferable embodiment, the angle angled at an angle θ 502 is about 15 degrees. The angle θ 500 and the angle θ 502 adjusted in any suitable manner to optimize meniscus management. In one embodiment, the angle θ 500 and the angle θ 502 may be the same, and in another embodiment, the angle θ 500 and the angle θ 502 may be different. By angling the angled source inlet(s) 302 ′ and/or angling the angled source outlet(s) 304 ′, the border of the meniscus may be more clearly defined and therefore control the drying and/or cleaning the surface being processed.
FIG. 8A illustrates a side view of the proximity heads 106 and 106 b for use in a dual wafer surface cleaning and drying system in accordance with one embodiment of the present invention. In this embodiment, by usage of source inlets 302 and 306 to input IPA and DIW respectively along with the source outlet 304 to provide a vacuum, the meniscus 116 may be generated. In addition, on the side of the source inlet 306 opposite that of the source inlet 302 , there may be a source outlet 304 to remove DIW and to keep the meniscus 116 intact. As discussed above, in one embodiment, the source inlets 302 and 306 may be utilized for IPA inflow 310 and DIW inflow 314 respectively while the source outlet 304 may be utilized to apply vacuum 312 . It should be appreciated that any suitable configuration of source inlets 302 , source outlets 304 and source inlets 306 may be utilized. For example, the proximity heads 106 and 106 b may have a configuration of source inlets and source outlets like the configuration described above in reference to FIGS. 7A and 7B . In addition, in yet more embodiments, the proximity heads 106 and 106 b may be of a configuration as shown below in reference to FIGS. 9 through 15 . Any suitable surface coming into contact with the meniscus 116 may be dried by the movement of the meniscus 116 into and away from the surface.
FIG. 8B shows the proximity heads 106 and 106 b in a dual wafer surface cleaning and drying system in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 processes the top surface 108 a of the wafer 108 , and the proximity head 106 b processes the bottom surface of 108 b of the wafer 108 . By the inputting of the IPA and the DIW by the source inlets 302 and 306 respectively, and by use of the vacuum from the source outlet 304 , the meniscus 116 may be formed between the proximity head 106 and the wafer 108 and between the proximity head 106 b and the wafer 108 . The proximity heads 106 and 106 b , and therefore the meniscus 116 , may be moved over the wet areas of the wafer surface in an manner so the entire wafer 108 can be dried.
FIG. 9A illustrates a processing window 538 - 1 in accordance with one embodiment of the present invention. In one embodiment, the processing window 538 - 1 may include a plurality of source inlets 302 and 306 and also a plurality of source outlets 304 . The processing window 538 - 1 is a region on a proximity head 106 (or any other proximity head referenced herein) that may generate and control the meniscus 116 . Therefore, the processing window 538 - 1 may be a region that dries and/or cleans a wafer if the proximity head 106 is desired to be used in that manner. In one embodiment, the processing window 538 - 1 is a substantially rectangular shape. It should be appreciated that the size of the processing window 538 - 1 (or any other suitable processing window described herein) may be any suitable length and width (as seen from a top view).
FIG. 9B illustrates a substantially circular processing window 538 - 2 in accordance with one embodiment of the present invention. In one embodiment, the processing window 538 - 2 may include a plurality of source inlets 302 and 306 and also a plurality of source outlets 304 . The processing window 538 - 2 is a region on the proximity head 106 (or any other proximity head referenced herein) that may generate and control the meniscus 116 . Therefore, the processing window 538 - 2 may be a region that dries and/or cleans a wafer if the proximity head 106 is desired to be used in that manner. In one embodiment, the processing window 538 - 2 is a substantially circular shape.
FIG. 9C illustrates a processing window 538 - 3 in accordance with one embodiment of the present invention. In one embodiment, the processing window 538 - 3 may include a plurality of source inlets 302 and 306 and also a plurality of source outlets 304 . The processing window 538 - 3 is a region on the proximity head 106 (or any other proximity head referenced herein) that may generate and control the meniscus 116 . Therefore, the processing window 538 - 3 may be a region that dries and/or cleans a wafer if the proximity head 106 is desired to be used in that manner. In one embodiment, the processing window 538 - 3 is a substantially oval in shape.
FIG. 9D illustrates a processing window 538 - 4 in accordance with one embodiment of the present invention. In one embodiment, the processing window 538 - 4 may include a plurality of source inlets 302 and 306 and also a plurality of source outlets 304 . The processing window 538 - 4 is a region on the proximity head 106 (or any other proximity head referenced herein) that may generate and control the meniscus 116 . Therefore, the processing window 538 - 4 may be a region that dries and/or cleans a wafer if the proximity head 106 is desired to be used in that manner. In one embodiment, the processing window 538 - 4 is a substantially square shape.
FIG. 10A shows an exemplary process window 538 - 1 with the plurality of source inlets 302 and 306 as well as the plurality of source outlets 304 in accordance with one embodiment of the present invention. In one embodiment, the process window 538 - 1 in operation may be moved in direction 546 across a wafer during, for example, a wafer drying operation. In such an embodiment, a proximity head 106 may encounter fluids on a wafer surface on a leading edge region 548 . The leading edge region 548 is an area of the proximity head 106 that, in a drying process, encounters fluids first. Conversely a trailing edge region 560 is an area of the proximity head 106 that encounters the area being processed last. As the proximity head 106 and the process window 538 - 1 included therein move across the wafer in the direction 546 , the wet area of the wafer surface enter the process window 538 - 1 through the leading edge region 548 . Then after processing of the wet region of the wafer surface by the meniscus that is generated and controllably maintained and managed by the process window 538 - 1 , the wet region is dried and the dried region of the wafer (or substrate) leaves the process window 538 - 1 through a trailing edge region 560 of the proximity head 106 . As discussed in reference to FIGS. 9A through 9D , the process window 538 - 1 may be any suitable shape such as, for example, rectangular, square, circular, oval, semi-circular, etc.
FIG. 10B shows processing regions 540 , 542 , and 544 of a proximity head 106 in accordance with one embodiment of the present invention. In one embodiment, the processing regions 540 , 542 , and 544 (the regions being shown by the broken lines) make up the processing window as discussed in reference to FIG. 10A . It should be appreciated that the processing regions 540 , 542 , and 544 may be any suitable size and/or shape such as, for example, circular, ring, semi-circular, square, semi-square, free form, etc. as long as a stable and controllable fluid meniscus can be generated that can apply and remove fluids from a surface in an efficient manner. In one embodiment, the processing region 540 includes the plurality of source inlets 302 , the processing region 542 (also known as a vacuum ring) includes the plurality of source outlets 304 , and the processing region 544 includes the plurality of source inlets 306 . In a preferable embodiment, the region 542 surrounds (or substantially surrounds) the region 544 with a ring of source outlets 304 (e.g., a vacuum ring). The region 540 substantially surrounds the region 544 but has an opening 541 where there are no source inlets 302 exist on a leading edge side of the process window 538 - 1 .
Therefore, in operation, the proximity head 106 generates a fluid meniscus by application of IPA, DIW, and vacuum, in the regions 540 , 542 , and 544 in the process window 538 (as shown in FIG. 10A ). When the proximity head 106 is moving over the wafer surface in an exemplary drying operation, the wafer surface that moves through the opening 541 in the region 542 and contacts the meniscus 116 within the process window 538 is dried. The drying occurs because fluid that is on that portion of the wafer surface that contacts the meniscus 116 is removed as the meniscus moves over the surface. Therefore, wet surfaces of a wafer may enter the process window 538 through the opening 541 in the region 540 and by contacting the fluid meniscus may undergo a drying process.
It should be appreciated that although the plurality of source inlets 302 , the plurality of source inlets 306 , and the plurality of source outlets 304 are shown in this embodiment, other embodiments may be utilized where any suitable number of the source inlets 302 , the source inlets 306 , and the source outlets 304 may be utilized as long as the configuration and number of the plurality of source inlets 302 , the source inlets 306 , and the source outlets 306 may generate a stable, controllable fluid meniscus that can dry a surface of a substrate. It should be understood that any suitable type of substrate such as, for example, a semiconductor wafer may be processed by the apparatuses and methodology described herein.
FIGS. 11 through 14 illustrate exemplary embodiments of the proximity head 106 . It should be appreciated any of the different embodiments of the proximity head 106 described may be used as one or both of the proximity heads 106 a and 106 b described above in reference to FIGS. 2A through 5H . As shown by the exemplary figures that follow, the proximity head may be any suitable configuration or size that may enable the fluid removal process as described in FIGS. 6 to 10 . Therefore, any, some, or all of the proximity heads described herein may be utilized in any suitable wafer cleaning and drying system such as, for example, the system 100 or a variant thereof as described in reference to FIGS. 2A to 2D . In addition, the proximity head may also have any suitable numbers or shapes of source outlets 304 and source inlets 302 and 306 . It should be appreciated that the side of the proximity heads shown from a top view is the side that comes into close proximity with the wafer to conduct wafer processing. All of the proximity heads described in FIGS. 11 through 14 are manifolds that enable usage of the IPA-vacuum-DIW orientation in a process window or a variant thereof as described above in reference to FIGS. 2 through 10 . The embodiments of the proximity head 106 as described below in reference to FIGS. 11 through 14 all have embodiments of the process window 538 , and regions 540 , 542 , and 544 as described in reference to FIGS. 9A through 10B above. In addition, the proximity heads described herein may be utilized for either cleaning or drying operations depending on the fluid that is inputted and outputted from the source inlets 302 and 306 , and the source outlets 304 . In addition, the proximity heads described herein may have multiple inlet lines and multiple outlet lines with the ability to control the relative flow rates of liquid and/or vapor and/or gas through the outlets and inlets. It should be appreciated that every group of source inlets and source outlets can have independent control of the flows.
It should be appreciated that the size as well as the locations of the source inlets and outlets may be varied as long as the meniscus produced is stable. In one embodiment, the size of the openings to source inlets 302 , source outlets 304 , and source inlets 306 are between about 0.02 inch and about 0.25 inch in diameter. In a preferable embodiment, the size of the openings of the source inlets 306 and the source outlets 304 is about 0.06 inch, and the size of the openings of the source inlets 302 is about 0.03 inch.
In one embodiment the source inlets 302 and 306 in addition to the source outlets 304 are spaced about 0.03 inch and about 0.5 inch apart. In a preferable embodiment, the source inlets 306 are spaced 0.125 inch apart from each other and the source outlets 304 are spaced 0.125 inch apart and the source inlets 302 are spaced about 0.06 inch apart.
Additionally, the proximity heads may not necessarily be a “head” in configuration but may be any suitable configuration, shape, and/or size such as, for example, a manifold, a circular puck, a bar, a square, an oval puck, a tube, a plate etc., as long as the source inlets 302 , and 306 , and the source outlets 304 may be configured in a manner that would enable the generation of a controlled, stable, manageable fluid meniscus. In a preferable embodiment, the proximity head may be a type of manifold as described in reference to FIGS. 10A through 14C . The size of the proximity heads may be varied to any suitable size depending on the application desired. In one embodiment, the length (from a top view showing the process window) of the proximity heads may be between 1.0 inch to about 18.0 inches and the width (from a top view showing the process window) may be between about 0.5 to about 6.0 inches. Also when the proximity head may be optimized to process any suitable size of wafers such as, for example, 200 mm wafers, 300, wafers, etc. The process windows of the proximity heads may be arranged in any suitable manner as long as such a configuration may generate a controlled stable and manageable fluid meniscus.
FIG. 11A shows a top view of a proximity head 106 - 1 with a substantially rectangular shape in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 - 1 includes three of the source inlets 302 which, in one embodiment, applies IPA to a surface of the wafer 108 .
In this embodiment, the source inlets 302 are capable of applying IPA toward a wafer surface region, the source inlets 306 are capable of applying DIW toward the wafer surface region, and the source outlets 304 are capable of applying vacuum to a region in close proximity of a surface of the wafer 108 . By the application of the vacuum, the IPA, DIW, and any other type of fluids that may reside on a wafer surface may be removed.
The proximity head 106 - 1 also includes ports 342 a , 342 b , and 342 c that, in one embodiment, correspond to the source inlet 302 , source outlet 304 , and source inlet 306 respectively. By inputting or removing fluid through the ports 342 a , 342 b , and 342 c , fluids may be inputted or outputted through the source inlet 302 , the source outlet 304 , and the source inlet 306 . Although the ports 342 a , 342 b , and 342 c correspond with the source inlet 302 , the source outlet 304 , and the source inlet 306 in this exemplary embodiment, it should be appreciated that the ports 342 a , 342 b , and 342 c may supply or remove fluid from any suitable source inlet or source outlet depending on the configuration desired. Because of the configuration of the source inlets 302 and 306 with the source outlets 304 , the meniscus 116 may be formed between the proximity head 106 - 1 and the wafer 108 . The shape of the meniscus 116 may vary depending on the configuration and dimensions of the proximity head 106 - 1 .
It should be appreciated that the ports 342 a , 342 b , and 342 c for any of the proximity heads described herein may be any suitable orientation and dimension as long as a stable meniscus can be generated and maintained by the source inlets 302 , source outlets 304 , and source inlets 306 . The embodiments of the ports 342 a , 342 b , and 342 c described herein may be applicable to any of the proximity heads described herein. In one embodiment, the port size of the ports 342 a , 342 b , and 342 c may be between about 0.03 inch and about 0.25 inch in diameter. In a preferable embodiment, the port size is about 0.06 inch to 0.18 inch in diameter. In one embodiment, the distance between the ports is between about 0.125 inch and about 1 inch apart. In a preferable embodiment, the distance between the ports is between about 0.25 inch and about 0.37 inch apart.
FIG. 11B illustrates a side view of the proximity head 106 - 1 in accordance with one embodiment of present invention. The proximity head 106 - 1 includes the ports 342 a , 342 b , and 342 c . In one embodiment, the ports 342 a , 342 b , and 342 c feed source inlets 302 , source outlets 304 , and the source inlets 306 respectively. It should be understood that the ports may be any suitable number, size, or shape as long as the source inlets 302 and 306 as well as source outlets 304 may be utilized to generate, maintain, and manage the meniscus 116 .
FIG. 11C shows a rear view of the proximity head 106 - 1 in accordance with one embodiment of the present invention. The rear view of the proximity head 106 - 1 , in one embodiment, corresponds to the leading edge 548 of the proximity head 106 - 1 . It should be appreciated that the proximity head 106 - 1 is exemplary in nature and may be any suitable dimension as long as the source inlets 302 and 306 as well as the source outlet 304 are configured in a manner to enable cleaning and/or drying of the wafer 108 in the manner described herein. In one embodiment, the proximity head 106 - 1 includes the input ports 342 c which may feed fluid to at least some of the source inlets 302 a which run parallel to the input ports 342 c shown in FIG. 11C .
FIG. 12A shows a proximity head 106 - 2 with a partial rectangular and partial circular shape in accordance with one embodiment of the present invention. In this embodiment, the proximity head 106 - 2 includes one row of source inlets 306 that is adjacent on both sides to rows of source outlets 304 . One of the rows of source outlets 304 is adjacent to two rows of source inlets 302 . Perpendicular to and at the ends of the rows described above are rows of source outlets 304 .
FIG. 12B shows a side view of the proximity head 106 - 2 with a partial rectangular and partial circular shape in accordance with one embodiment of the present invention. In one embodiment, the proximity head 106 - 2 includes ports 342 a , 342 b , and 342 c on a side of the proximity head 106 - 2 . The ports 342 a , 342 b , and 342 c may be utilized to input and/or output fluids through the source inlets 302 and 306 and the source outlets 304 . In one embodiment, the ports 342 a , 342 b , and 342 c correspond to the source inlets 302 , the source outlets 304 , and the source inlets 306 respectively.
FIG. 12C shows a back view of the proximity head 106 - 2 with a partial rectangular and partial circular shape in accordance with one embodiment of the present invention. The back side as shown by the rear view is where the back side is the square end of the proximity head 106 - 2 .
FIG. 13A shows a rectangular proximity head 106 - 3 in accordance with one embodiment of the present invention. In one embodiment, the proximity head 106 - 3 includes a configuration of source inlets 302 and 306 and source outlets 304 ′ that is similar to the proximity head 106 - 1 as discussed in reference to FIG. 11A . The rectangular proximity head 106 - 3 includes the source outlets 304 ′ that are larger in diameter than the source outlets 304 . In any of the proximity heads described herein, the diameter of the source inlets 302 and 306 as well as the source outlets 304 may be altered so meniscus generation, maintenance, and management may be optimized. In this embodiment, the source inlets 302 are capable of applying IPA toward a wafer surface region, the source inlets 306 are capable of applying DIW toward the wafer surface region, and the source outlets 304 are capable of applying vacuum to a region in close proximity of a surface of the wafer 108 . By the application of the vacuum, the IPA, DIW, and any other type of fluids that may reside on a wafer surface may be removed.
The proximity head 106 - 3 also includes ports 342 a , 342 b , and 342 c that, in one embodiment, correspond to the source inlet 302 , source outlet 304 , and source inlet 306 respectively. By inputting or removing fluid through the ports 342 a , 342 b , and 342 c , fluids may be inputted or outputted through the source inlet 302 , the source outlet 304 , and the source inlet 306 . Although the ports 342 a , 342 b , and 342 c correspond with the source inlet 302 , the source outlet 304 , and the source inlet 306 in this exemplary embodiment, it should be appreciated that the ports 342 a , 342 b , and 342 c may supply or remove fluid from any suitable source inlet or source outlet depending on the configuration desired. Because of the configuration of the source inlets 302 and 306 with the source outlets 304 , the meniscus 116 may be formed between the proximity head 106 - 1 and the wafer 108 . The shape of the meniscus 116 may vary depending on the configuration and dimensions of the proximity head 106 - 1 .
It should be appreciated that the ports 342 a , 342 b , and 342 c for any of the proximity heads described herein may be any suitable orientation and dimension as long as a stable meniscus can be generated and maintained by the source inlets 302 , source outlets 304 , and source inlets 306 . The embodiments of the ports 342 a , 342 b , and 342 c described in relation to the proximity head 106 - 1 may be applicable to any of the proximity heads described in reference to the other Figures. In one embodiment, the port size of the ports 342 a , 342 b , and 342 c may be between about 0.03 inch and about 0.25 inch in diameter. In a preferable embodiment, the port size is about 0.06 inch to 0.18 inch in diameter. In one embodiment, the distance between the ports is between about 0.125 inch and about 1 inch apart. In a preferable embodiment, the distance between the ports is between about 0.25 inch and about 0.37 inch apart.
FIG. 13B shows a rear view of the proximity head 106 - 3 in accordance with one embodiment of the present invention. The rear view of the proximity head 106 - 3 , in one embodiment, corresponds to the leading edge 548 of the proximity head 106 - 3 . It should be appreciated that the proximity head 106 - 3 is exemplary in nature and may be any suitable dimension as long as the source inlets 302 and 306 as well as the source outlet 304 are configured in a manner to enable cleaning and/or drying of the wafer 108 in the manner described herein. In one embodiment, the proximity head 106 - 3 includes the input ports 342 c which may feed fluid to at least some of the source inlets 302 a which run parallel to the input ports 342 c shown in FIG. 13A .
FIG. 13C illustrates a side view of the proximity head 106 - 3 in accordance with one embodiment of present invention. The proximity head 106 - 3 includes the ports 342 a , 342 b , and 342 c . In one embodiment, the ports 342 a , 342 b , and 342 c feed source inlets 302 , source outlets 304 , and the source inlets 306 respectively. It should be understood that the ports may be any suitable number, size, or shape as long as the source inlets 302 and 306 as well as source outlets 304 may be utilized to generate, maintain, and manage the meniscus 116 .
FIG. 14A shows a rectangular proximity head 106 - 4 in accordance with one embodiment of the present invention. In one embodiment, the proximity head 106 - 4 includes a configuration of source inlets 302 and 306 and source outlets 304 ′ that is similar to the proximity head 106 - 3 as discussed in reference to FIG. 13A . The rectangular proximity head 106 - 3 includes the source outlets 304 ′ that are larger in diameter than the source outlets 304 . In any of the proximity heads described herein, the diameter of the source inlets 302 and 306 as well as the source outlets 304 may be altered so meniscus generation, maintenance, and management may be optimized. In one embodiment, the source outlets 304 ′ are located closer to the source inlets 302 than the configuration discussed in reference to FIG. 13A . With this type of configuration, a smaller meniscus may be generated. The region spanned by the source inlets 302 , 306 and source outlets 304 ′ (or also source outlets 304 as described in reference to FIG. 11A ) may be any suitable size and/or shape. In one embodiment, the process window may be between about 0.03 to about 9.0 square inches. In a preferable embodiment, the process window may be about 0.75 inch. Therefore, by adjusting the region of the In this embodiment, the source inlets 302 are capable of applying IPA toward a wafer surface region, the source inlets 306 are capable of applying DIW toward the wafer surface region, and the source outlets 304 are capable of applying vacuum to a region in close proximity of a surface of the wafer 108 . By the application of the vacuum, the IPA, DIW, and any other type of fluids that may reside on a wafer surface may be removed.
The proximity head 106 - 3 also includes ports 342 a , 342 b , and 342 c that, in one embodiment, correspond to the source inlet 302 , source outlet 304 , and source inlet 306 respectively. By inputting or removing fluid through the ports 342 a , 342 b , and 342 c , fluids may be inputted or outputted through the source inlet 302 , the source outlet 304 , and the source inlet 306 . Although the ports 342 a , 342 b , and 342 c correspond with the source inlet 302 , the source outlet 304 , and the source inlet 306 in this exemplary embodiment, it should be appreciated that the ports 342 a , 342 b , and 342 c may supply or remove fluid from any suitable source inlet or source outlet depending on the configuration desired. Because of the configuration of the source inlets 302 and 306 with the source outlets 304 , the meniscus 116 may be formed by the process window between the proximity head 106 - 1 and the wafer 108 . The shape of the meniscus 116 may correspond with the shape of the process window and therefore the size and shape of the meniscus 116 may be varied depending on the configuration and dimensions of the regions of source inlets 302 and 306 and regions of the source outlets 304 .
FIG. 14B shows a rear view of the rectangular proximity head 106 - 4 in accordance with one embodiment of the present invention. The rear view of the proximity head 106 - 4 , in one embodiment, corresponds to the leading edge 548 of the proximity head 106 - 4 . It should be appreciated that the proximity head 106 - 4 is exemplary in nature and may be any suitable dimension as long as the source inlets 302 and 306 as well as the source outlet 304 are configured in a manner to enable cleaning and/or drying of the wafer 108 in the manner described herein. In one embodiment, the proximity head 106 - 4 includes the input ports 342 c which may feed fluid to at least some of the source inlets 302 a which run parallel to the input ports 342 c shown in FIG. 13A .
FIG. 14C illustrates a side view of the rectangular proximity head 106 - 4 in accordance with one embodiment of present invention. The proximity head 106 - 4 includes the ports 342 a , 342 b , and 342 c . In one embodiment, the ports 342 a , 342 b , and 342 c feed source inlets 302 , source outlets 304 , and the source inlets 306 respectively. It should be understood that the ports may be any suitable number, size, or shape as long as the source inlets 302 and 306 as well as source outlets 304 may be utilized to generate, maintain, and manage the meniscus 116 .
FIG. 15A shows a proximity head 106 in operation according to one embodiment of the present invention. It should be appreciated that the flow rate of the DIW and the IPA, the magnitude of the vacuum, and rotation/movement of the wafer being processed may be varied in any suitable manner to provide optimal fluid meniscus controllability and management to generate enhanced wafer processing. The proximity head 106 , in one exemplary embodiment, is utilized in a configuration as described in reference to FIG. 2A . As shown in reference to FIGS. 15A through 15F , the wafer is a clear material so fluid meniscus dynamics can be seen with different flow rates, vacuum rates, and wafer rotations. The flow rate of DIW and IPA as well as the vacuum and rotation of the wafer may be varied depending on the conditions encountered during drying. In FIG. 15A , the meniscus has been formed by input of DIW and vacuum without any IPA flow. Without the IPA flow, the meniscus has an uneven boundary. In this embodiment, the wafer rotation is zero and the DIW flow rate is 500 ml/min.
FIG. 15B illustrates the proximity head 106 as described in FIG. 15A with IPA input in accordance with one embodiment of the present invention. In this embodiment, the DIW flow rate is 500 ml/min and the IPA flow rate is 12 ml/min with the rotation of the wafer being zero. As shown by FIG. 15B , the usage of IPA flow has made the boundary of the meniscus more even. Therefore, the fluid meniscus is more stable and controllable.
FIG. 15C shows the proximity head 106 as described in FIG. 15B , but with the IPA flow increased to 24 ml/min in accordance with one embodiment of the present invention. The rotation has been kept at zero and the flow rate of the DIW is 500 ml/min. When the IPA flow rate is too high, the fluid meniscus becomes deformed and less controllable.
FIG. 15D shows the proximity head 106 where the fluid meniscus is shown where the wafer is being rotated in accordance with one embodiment of the present invention. In this embodiment, the rotation of the wafer is 10 rotations per minute. The flow rate of the DIW is 500 ml/min while the flow rate of the IPA is 12 SCFH. The magnitude of the vacuum is about 30 in Hg@ 80 PSIG. When the wafer is rotated, the fluid meniscus becomes less stable due to the added wafer dynamics as compared with FIG. 15C which shows the same DIW and IPA flow rate but without wafer rotation.
FIG. 15E shows the proximity head 106 where the fluid meniscus is shown where the wafer is being rotated faster than the rotation shown in FIG. 15D in accordance with one embodiment of the present invention. In this embodiment, the rotation of the wafer is 15 rotations per minute. The flow rate of the DIW is 500 ml/min while the flow rate of the IPA is 12 SCFH. The magnitude of the vacuum is about 30 in HG@ 80 PSIG. When the wafer is rotated faster, the fluid meniscus has a more uneven boundary as compared to the fluid meniscus discussed in reference to FIG. 15D due to the added wafer dynamics as compared.
FIG. 15F shows the proximity head 106 where the IPA flow has been increased as compared to the IPA flow of FIG. 15D in accordance with one embodiment of the present invention. In this embodiment, the variables such as the DIW flow rate, rate of wafer rotation, and vacuum magnitude are the same as that described in reference to FIG. 15D . In this embodiment, the IPA flow rate was increased to 24 SCFH. With the IPA flow rate increased, the IPA holds the fluid meniscus along the border to generate a highly controllable and manageable fluid meniscus. Therefore, even with wafer rotation, the fluid meniscus looks stable with a consistent border that substantially corresponds to the region with the plurality of source inlets 302 and the region with the plurality of source outlets 304 . Therefore, a stable and highly controllable, manageable, and maneuverable fluid meniscus is formed inside of the process window so, in an exemplary drying process, fluid that the proximity head 106 may encounter on a wafer surface is removed thereby quickly and efficiently drying the wafer surface.
FIG. 16A shows a top view of a cleaning/drying system 602 in accordance with one embodiment of the present invention. It should be appreciated that any of the embodiments of the drying system 100 (e.g., cleaning systems 100 - 1 , 100 - 2 , 100 - 3 , 100 - 4 , and 100 - 5 ) described herein with the any of the embodiments of the proximity head 106 described in FIGS. 2A to 15F herein may be utilized in conjunction with other wafer processing technologies to generate an integrated system such as, for example, those described in FIG. 16A through 20 below. In one embodiment, the cleaning and drying system 100 may be incorporated into a 2300 Brush Box Assembly manufactured by Lam Research of Fremont, Calif.
In one embodiment, the cleaning/drying system 602 is the cleaning and drying system 100 - 5 described above in reference to FIGS. 5G and 5H with a brush core 604 and a spray manifold 606 . In such an embodiment, when one of the cleaning and drying systems 100 are utilized in conjunction with a different wafer processing apparatus, the cleaning and drying systems (or components therein) may also be known as a wafer drying insert. It should be understood that the brush may be made out of any suitable material that may effectively clean a substrate such as, for example, polyvinyl alcohol (PVA), rubber, urethane, etc. In one embodiment, a brush such, as for example a polyvinyl alcohol (PVA) brush may be applied over the brush core 604 . The brush core 604 may be any suitable brush core configuration such as, for example, those known to those skilled in the art. Therefore, when the brush core 604 rotates, the brush on the brush core 604 may be applied to the wafer 102 to clean the surface of the wafer after wafer processing such as, for example, etching, planarization, etc.
In one embodiment, after the wafer 102 is cleaned by the brush, the wafer 102 does not have to be taken out of the cleaning/drying 602 (also known as a cleaning/drying module) for drying. Therefore, after wafer cleaning, the wafer 102 may be dried as discussed above in reference to FIGS. 2A through 15C above. In this fashion, time may be saved by having two wafer process operation in one module and chances for contamination are reduced because the wafer 102 does not have to be taken to a different module for cleaning.
FIG. 16B shows an alternative view of the cleaning/drying system 602 in accordance with one embodiment of the present invention. The cleaning/drying system 602 may be a module(s) (e.g., cluster tool) in a variety of wafer processing systems as discussed below in reference to FIG. 17 though 21 . By having both a cleaning system and a drying system in one module, space may be saved and the wafer processing system may be made smaller and more compact while retaining substantially the same functionality.
FIG. 17 illustrates a wafer processing system 700 with front end frame assembly 705 with a drying module 704 in accordance with one embodiment of the present invention. The drying module 704 may be any of the systems 100 , 100 - 1 , 100 - 2 , 100 - 3 , 100 - 4 , 100 - 5 , and any suitable variant thereof. It should be appreciated that any suitable number of drying modules 704 such as, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. may be connected to the front end frame assembly 705 to generate the wafer processing system 700 with varying levels of wafer processing capabilities. It should also be understood that any other types of wafer processing tools may be connected to the front end frame assembly 705 such as, for example, a planarization tool/module, etching tool/module, cleaning tool/module, etc.
In one embodiment, the wafer processing system 700 includes 6 drying modules 704 and also has a robot 712 that may feed and remove wafers into and out of the drying modules 704 . The robot 712 may also be configured to feed and remove wafers into and out of the front end loaders 710 . It should be understood that any suitable number and types of robots 712 may be utilized as well as any suitable number and types of front end loaders 710 . In one embodiment, the front end loaders 710 may receive a cartridge full of wafers which require processing by the wafer processing system 700 .
FIG. 18 shows a wafer processing system 800 which has multiple wafer processing tools in accordance with one embodiment of the present invention. In one embodiment, the wafer processing system 800 includes an etching module 722 , the drying module 704 , the front end loader 710 , and the robot 712 located on a frame assembly 720 . The wafer processing system 700 as with the wafer processing system 800 may have any suitable number and any suitable types of modules/tools such as, CMP modules, megasonic processing modules, cleaning modules, and etching modules. Therefore an apparatus such as, for example, the wafer processing system 800 with different substrate/wafer processing modules may, in one embodiment, be called a cluster architecture system. In one embodiment, a drying system as described herein may be an integrated drying system when integrated with other modules to form the cluster architecture system. In an alternative embodiment, the wafer processing system 800 may have the etching module 722 , the drying module 704 , and a cleaning module. In one embodiment, the wafer processing system 700 may include three of the etching modules 622 , and 6 of the drying modules 704 . When multiple wafer processing occurs, this may be known as cluster processing. It should also be appreciated that any or all of the drying modules 704 may be replaced with a module containing the cleaning/drying system 602 so both cleaning and drying may be accomplished in the same module.
FIG. 19 shows a wafer processing system 800 ′ without the etching module 722 in accordance with one embodiment of the present invention. In one embodiment, the wafer processing system 800 has the frame 720 containing a plurality of the drying modules 704 . The wafer processing system 800 ′ may contain any suitable number of drying modules 704 . In one embodiment, the wafer processing system 800 ′ includes 8 of the drying modules 704 . The wafer 102 is shown being loaded into the wafer processing system 800 through use of the front end loader 710 . The robot 712 may take the wafer from the front end loader 710 and load the wafer 102 into any one of the plurality of drying modules 704 . In this embodiment, the etching module 722 shown above in reference to FIG. 18 has been removed to generate space to add more drying modules 704 . In addition, the drying modules 704 may include the cleaning and drying system 602 described in further detail in reference to FIG. 16A . In this way both drying and cleaning may be accomplished within one module.
FIG. 20 illustrates a wafer processing system 800 ″ which includes a drying module 704 and a cleaning module 850 in accordance with one embodiment of the present invention. In one embodiment, the wafer processing system 800 ″ can include a separate cleaning module such as, for example, the cleaning module 850 . It should be appreciated that any suitable number and/or types of cleaning apparatuses may be utilized within the wafer processing system 800 ″, such as a brush box (or wafer brush scrubbing units), megasonic cleaning device, etc. In one embodiment, the cleaning module 850 may be a brush box. The brush box may be any suitable type of brush box that can effectively clean wafers such as known to those skilled in the art.
In yet another embodiment, the wafer processing system 800 ″ may have a cleaning module 850 that is a megasonic module. In another embodiment, the megasonic module may conduct other types of processing besides cleaning. Any suitable megasonic processing device may be utilized as a megasonic module such as, for example, those described in U.S. patent application Ser. No. 10/259,023 entitled “MEGASONIC SUBSTRATE PROCESSING MODULE”. The aforementioned patent application is hereby incorporated by reference. Therefore, by having various types of modules or wafer processing devices interconnected, wafer processing systems may be generated that have the capability to utilized multiple wafer processing methods.
FIG. 21 shows a block diagram of a wafer processing system 900 in accordance with one embodiment of the present invention. In one embodiment, the system 900 includes a cleaning system 902 , a chemical mechanical planarization (CMP) system 904 , a megasonic system 906 , and an etching system 908 with a deposition system. The system 900 also includes a robotics 912 that can transport substrates to and from each of the systems 902 , 904 , 906 , 908 , and 910 . Therefore, the system 900 may include all of the major wafer processing tools. It should be understood that the system 900 can include one, some, or all of the systems 902 , 904 , 906 , 908 , and 910 . It should also be appreciated that the system 900 can include any suitable number of any of the systems 902 , 904 , 906 , 908 , and 910 as well as other types of wafer processing systems known to those skilled in the art. Therefore, the system 900 has great flexibility in wafer processing abilities depending on the desires of a manufacturer or user.
The cleaning system 902 may be any suitable cleaning system such as, for example, brush box(es), spin, rinse, and dry (SRD) apparatus(es), etc. Any suitable type of brush box or SRD apparatuses may be utilized in the system 900 . The CMP system 904 may be any suitable type of CMP apparatus such as those utilizing, for example, a table, one or more belts, etc. The megasonic system may be one as described above in reference to the megasonic processing device as described in further detail in reference to FIG. 20 . The etching system 908 may be any type of substrate etching device such as, for example, one that includes a robot that can obtain a wafer through a load lock and process the wafer in any number of process modules where etching can take place. A deposition system can optionally be utilized along with the etching system 908 .
The drying system 910 may be any drying system described herein that utilize any of the different embodiments of the proximity head 106 as described above in reference to FIGS. 2A through 14C . Therefore, the drying system may be the system 100 , 100 - 1 , 100 - 2 , 100 - 3 , 100 - 4 or any variant thereof. Therefore, the system 900 may process the wafer 102 in any suitable number ways and dry the wafer 102 in a highly efficient and cost effective manner by usage of the drying system 910 of the present invention. Therefore, the drying system 910 may lower of wafer production costs and raise wafer yields.
While this invention has been described in terms of several preferred embodiments, it will be appreciated that those skilled in the art upon reading the preceding specifications and studying the drawings will realize various alterations, additions, permutations and equivalents thereof. It is therefore intended that the present invention includes all such alterations, additions, permutations, and equivalents as fall within the true spirit and scope of the invention.
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Method for processing a substrate are provided. The processing occurs when the substrate is moved between cluster tools. One method includes providing the substrate to a cluster tool, and the cluster tool is configured to move the substrate into a meniscus processing module having at least one proximity head. The proximity head is configured to perform operations including applying a fluid onto a region of a surface of the substrate, such the fluid is continuously flown so as to substantially fill the region between a surface of the proximity head and the surface of the substrate. An operation of removing the fluid from the region by applying a vacuum force through the proximity head is also provided. The applying and removing is operated substantially simultaneously so that the fluid forms a controlled fluid meniscus that remains between the surface of the substrate and the surface of the proximity head when the proximity head is positioned over the substrate. The method can include moving one of the controlled fluid meniscus or the substrate so that the controlled fluid meniscus is caused to contact regions of the surface of the substrate to cause fluid processing of the surface of the substrate when in the meniscus processing module. The method can also include moving the substrate out of the meniscus processing module and into a next module of the of the cluster tool or out of the cluster tool.
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FIELD OF THE INVENTION
1. Background of the Invention
The present invention relates to negative dobbies of the type incorporating swinging levers, intended for controlling the heddle frames in weaving looms.
2. Description of the Related Art
French Patent No. 2 609 476 describes an improved negative dobby in which each of the two articulated hooks mounted on each swinging lever cooperates with a pivoting member constituted by a bolt disposed between the bearing face of a hook and the pin on which the hook pivots on the swinging lever.
FIGS. 1 and 2 of the accompanying drawings substantially reproduce FIGS. 3 and 4 of the above-mentioned Application. In FIG. 1, reference 1 designates one of the swinging levers of the dobby, displaced cyclically about its articulation point 2 by the two rear crosspieces 3, which form bearings for the heel of the hooks 4 articulated at 5 on the ends of said swinging lever 1. The articulation point 2 of the swinging lever 1 is carried by a lever 6 coupled to. The corresponding heddle frame, the displacement of the heddle frame is controlled by a reading device 7 common to all the swinging levers of the dobby.
To that end, with each hook 4 there is associated a two-armed bolt 8 which is articulated on a pin 9 so as to pivot in one direction or in the other under the effect of a pusher 10 actuated by the reading device 7. It should be observed that the pin 9, thus disposed between the pivot 5 of the hook 4 and the bearing face 4a of the hook with which the bolt 8 is adapted to cooperate by one of its arms, is located, not strictly on the straight line Y-Z or line of ,force which joins pin 5 and face 4a, but in an offset manner (distance d) with respect to Y-Z line towards the outside, i.e. in the direction of the body of the conjugate hook 4, so as to generate a couple or moment of force which tends to rotate the bolt 8 and thus apply the inner face of the hook 4 against the pin 9.
Consequently, a perfectly stable bearing position is obtained. Furthermore and especially, the bolts 8 are subject to compression, so that they may exhibit, in order to withstand equivalent resistant efforts without damage, a reduced mass with respect to the conventional hooks subject to engaging movement.
Nevertheless, studies have shown that, whatever the advantages obtained, such a structure still presented appreciable drawbacks in practice.
It should firstly be noted that the retention or engagement of hook 4 on bolt 8 is not positive. Consequently, under the effect of the vibrations inherent in the operation of the dobby, as well as the variations of the return force exerted on each hook 4, there is a considerable risk of untimely unhooking that must be overcome by using additional stops, which are expensive and subject to wear.
Furthermore, the lateral offset d of the pins 9 outwardly with respect to the line of force Y-Z makes it necessary to give the hooks 4 a marked elongated curvature. In fact, taking into account the relative path X between the tip of the hook 4 and the pin 9, it is necessary, in order to avoid any interference, to move the pin 9 away from the bearing face 4a and therefore to elongate hook 4 as well as bolt 8. The major portion of each hook 4 is thus spaced from the line of force Y-Z and is subjected to a considerable bending moment which necessitates hook to exhibit a large resistant through it's cross-section. Finally, this results in elongated, expensive and heavy hooks 4 which generate high forces of inertia, which are sources of untimely vibrations.
SUMMARY OF THE INVENTION
It is a principal object of the present invention to overcome these drawbacks, by providing a negative dobby incorporating double swinging levers for a weaving loom, of the type in which each of the ends of each swinging lever is provided with a pin on which is articulated a hook which cooperates with a bolt mounted to pivot on a pin in order to bear, by pivoting under the effect of the reading device of the dobby, against a bearing face of the hook. The dobby is characterized in that each hook presents, on its inwardly facing edge, a notch sectioned to receive the hub of the bolt in order to ensure positive retention, in all directions, of said hook when the bearing face thereof is applied against the bolt.
In fact, the invention consists in providing, at the inwardly facing edge of each hook, a notch sectioned to receive the hub of the corresponding bolt which is thus enveloped, consequently ensuring positive retention of the hook against any risk of unhooking.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which:
As indicated hereinbefore, FIGS. 1 and 2 reproduce FIGS. 3 and 4 of French Patent No. 2 609 476.
FIG. 3 is a partial side view of a hook/bolt assembly of a dobby according to the invention.
FIG. 4 is a partial side view illustrating the operation of the assembly of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring again to the drawings, in FIG. 3, reference 14 designates one (in fact the lower one) of the two hooks articulated at 15 on the ends of each swinging lever 1. The hook 14 has a bearing face 14a adapted to cooperate with the end of one of the two arms of a bolt 18 mounted to oscillate on a pin 19 and connected by a pusher 10 to the reading device, all being as in FIGS. 1 and 2.
However, it should be observed:
on the one hand, that pin 19 is offset inwardly with respect to the line of force Y-Z;
on the other hand, that each hook 14 is sectioned to comprise, on its edge facing the interior of the dobby, a notch 14b adapted to envelop the hub 18a of the bolt 18 (or at least the pivot pin 19 thereof).
It will be understood that such a structure radically opposes any risk of untimely unhooking of the hook 14 with respect to the bolt 18, whatever the magnitude of the vibrations of the dobby in the course of operation and the variations which affect the efforts to which the hooks 14 are subjected during the weaving operation.
Effectively, despite the direction of offset of pin 19 with respect to the line of force Y-Z, the hook 14 is positively retained in the three orientations N, S and O by the edge of notch 14b and, in the fourth orientation E, by the engagement of bearing face 14a against the end of the arm of the bolt.
In addition, the reversal of the offset of pin 19 makes it possible to shorten and reduces the weight of both the hooks 14 of the dobby and the bolts 18 associated therewith. As the hooks require a less marked curvature and the length of the bolts is reduced, avoiding any risk of interference along path X of the tip of each hook.
The dimensions of the assembly are consequently reduced, which is always a substantial advantage in the construction of dobbies. The lightweight of the bolts and hooks makes it possible to reduce the inertia exhibited by these moving components and to increase the speed of operation of the dobby, while limiting the efforts developed by the reading device for actuating the pushers 10 associated with the bolts
It will be readily imagined that the invention is applicable to dobbies of the type incorporating "drawn swinging levers" in which the reciprocating displacement of each lever 4 is ensured, no longer by thrust crosspieces, but by traction members in the form of hooks mounted to pivot on a beam disposed in front of the swinging levers and connected to the device driving the dobby in order to oscillate alternately in one direction and in the other. The members being controlled by the reading device of the dobby with a view to actuating each swinging lever as a function of the weave of the fabric to be made, in the manner described in U.S. Pat. No. 4 386 631 to MIZOGUCHI.
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The hooks associated with the swinging levers in a negative dobby of a weaving machine include a notch and opposing bearing face along their inner edges for positively retaining the hub and one arm of a bolt which is selectively actuated to engage each hook.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority of the Great Britain Application No. 1019216.9, filed on Nov. 12, 2010, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to CCDs (charge coupled devices).
[0003] FIG. 1 is a plan view of a part of a typical CCD, and FIG. 2 a sectional view. The CCD has an imaging area indicated generally by the reference numeral 1 consisting of an array of charge collection sites commonly known as pixels. The part of the array shown extends a little over ten pixels in the row direction and two in the column direction, and the pixels are denoted P 1 , 1 , P 1 , 2 , P 1 , 3 , . . . P 1 , 10 in the first row and P 2 , 1 , P 2 , 2 , P 2 , 3 , . . . P 2 , 10 in the second row. The scale in the column direction is enlarged compared to that in the row direction for the purposes of clarity. The full imaging area would typically extend to hundreds of pixels in each direction. In the vertical direction the pixel pitch is defined by horizontal parallel transfer electrodes R 1 / 1 , R 1 / 2 , R 1 / 3 for the first row and R 2 / 1 , R 2 / 2 , R 2 / 3 for the second row, to which various voltage phases are applied. The CCD illustrated is a three phase device.
[0004] While the image charge pattern is collected, the electrodes are held at fixed potentials. Electrons gather beneath the electrode or electrodes with the highest positive potential. When the exposure period has finished, clocking the electrodes by applying sequential voltages to the phases transfers all the packets of electrons down the device (as seen in the drawings) in the direction of the columns. Because usually all packets in a row move down simultaneously this is known as parallel transfer. The final transfer is into an output register (not shown) which extends in the same direction as the rows, but which has a serial read-out.
[0005] In general, modern CCD devices use polysilicon material as the electrodes. Polysilicon has the advantage of allowing light to pass through, of being electrically conductive and of allowing fine features to be etched. These electrodes, denoted as P in FIG. 2 , lie on a dielectric d 1 (silicon dioxide) on a silicon substrate S.
[0006] The height of a pixel in the column direction compared to the width of the imaging area is such that the electrodes are typically much longer in the row direction than they are in the column direction, often by a factor of 100 or more. The resistivity of polysilicon means there can be a significant resistance R along each electrode between the sides of the device (where commonly electrical connections are made to the electrodes) and the centre of the device. The electrodes also have capacitance C to the silicon S dependent on the dielectric used resulting in an electrical time constant. The effect of this time constant is to reduce the amplitude of the varying clock voltage at the horizontal centre of the device as the speed of the parallel transfer is increased. The reduced amplitude decreases the size of charge packets that can be moved and may allow them to spill, causing the image to appear smeared down the centre. Some applications require a very fast parallel transfer so this is undesirable.
[0007] A known technique to alleviate this problem is to add a horizontal strip of metal m 1 / 1 , m 1 / 2 , m 1 / 3 , m 2 / 1 , m 2 / 2 , m 2 / 3 over each electrode with contacts ‘a’ between the electrode and the metal at regular intervals along the length of the strip. There is a penalty that the strips reduce the light reaching the pixels in front-illuminated devices, but this does not apply if the device is back-thinned and illuminated from the backside. In FIG. 2 , the strips of metal are shown as the layer m over the silicon dioxide layer d 2 which grows over the polysilicon electrodes P. Each set of three horizontal strips are connected to respective terminals t 1 - 3 , t 4 - 6 (shown as t in FIG. 2 ), each set of three terminals being supplied with respective phase voltage IΦ 1 , IΦ 2 , IΦ 3 . Because the resistivity of the metal is much lower (typically 500 times lower than the polysilicon), the time constant is significantly reduced and much faster parallel transfers can be achieved.
[0008] Unfortunately the nature of silicon wafer processing means that it is difficult to define fine metal features. Therefore so far the technique has been limited to devices with large pixels with relatively wide electrodes in the column direction limiting its application
[0009] It has been proposed in a front-illuminated CCD (JP 2000-101061) to provide a set of V-shaped ( FIG. 10 ) metal strips in contact with corresponding phase electrodes. The strips are widely spaced to minimise the light-sensitive area they block, which restricts the amount by which the time constant is reduced, and are also driven at the sides and top of the light-sensitive area, which makes it difficult to adapt the design for frame transfer operation.
SUMMARY
[0010] The invention provides a back-illuminated CCD comprising a two dimensional array of charge collection sites arranged in rows and columns, each row being associated with a plurality of electrodes at the front face extending in the direction of the row and corresponding to respective phase voltages, and a plurality of conducting strips each having repeatedly reversing inclined portions, each portion being in electrical contact with the electrodes of corresponding phase voltage of two or more rows, and each portion being inclined relative to the rows in the opposite direction to that in which the preceding portion is inclined.
[0011] Compared to the prior front-illuminated device, the arrangement permits a higher density of conducting tracks and thus faster parallel transfer than hitherto, since the CCD is back-illuminated and the tracks do not obscure the charge collection sites, while allowing the drive connections to be made only at the sides of the array. Compared to the prior back-illuminated device, there is less than one conducting strip per row, and the arrangement is applicable to smaller pixels in the column direction.
[0012] Each conducting strip may be zig-zag in shape, or may have curved undulations, for example, it may be sinusoidal.
[0013] Advantageously, the inclined portions of each conducting strip are in electrical contact with the respective phase voltage electrodes of no more than ten rows, preferably no more than five rows. Preferably, each conducting strip is in electrical contact with its respective phase voltage electrodes at more than once per fifty charge collection sites in the row direction, preferably more than once per twenty-five charge collection sites.
[0014] In a frame transfer CCD, at least some of the conducting strips are preferably in electrical contact with the electrodes of at least one additional row, in order to allow separate operation of the clock voltages for the image and store regions without shorting.
[0015] The electrical connection may be achieved by etching away a region of dielectric which will have formed on the electrodes after they have been formed, before the conducting strip is deposited. The electrodes may be polysilicon electrodes, and the conducting strips may be of aluminium or copper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Ways of carrying out the invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:
[0017] FIG. 1 is a fragmentary plan view of part of a known CCD;
[0018] FIG. 2 is a schematic sectional view of the CCD shown in FIG. 1 ;
[0019] FIG. 3 is a fragmentary plan view of part of a CCD forming a first embodiment of the invention;
[0020] FIG. 4 is a schematic plan view of the CCD of FIG. 3 showing the clocking voltages;
[0021] FIG. 5 is a fragmentary plan view of part of a CCD forming a second embodiment of the invention; and
[0022] FIG. 6 is a schematic plan view of the CCD of FIG. 5 showing the clocking voltages.
[0023] Like parts have been given like reference numerals throughout all the Figures.
DETAILED DESCRIPTION
[0024] Referring to FIGS. 2 to 4 , a fragmentary region of a back-illuminated full frame CCD according to a first embodiment of the invention is shown. FIG. 3 shows a fragmentary region of the array, twelve pixels in the row direction, and eight in the column direction (P 1 , 1 , P 1 , 2 , P 1 , 3 . . . P 1 , 12 in the row direction and P 1 , 1 , P 2 , 1 , P 3 , 1 , . . . P 8 , 1 in the column direction). FIG. 4 shows only two of the columns of pixels. In section, the CCD appears the same as the known CCD shown in FIG. 2 .
[0025] In reality, the CCD would have hundreds of pixels in each row and hundreds in each column, a typical array extending 1024 by 1024. The CCD is seen in FIG. 3 in top plan, and the illumination strikes the CCD from beneath the plane of the drawing.
[0026] Referring to FIG. 4 , the clocking voltages are applied by lines IΦ 1 to IΦ 3 to respective terminals t 1 to t 6 . The rows of charge are transferred in parallel fashion to an output register 3 , which outputs the charge in serial fashion in the direction of the arrow A.
[0027] While the image charge pattern is collected, the electrodes are held at fixed potentials. Electrons gather beneath the electrode or electrodes with the highest positive potential. When the exposure period has finished, clocking the electrodes by applying sequential voltages to the phases transfers all the packets of electrons down the device (as seen in the drawings) in the direction of the columns.
[0028] There are three electrodes ( FIG. 3 ) corresponding to each row. In the case of the first row, the electrodes are R 1 / 1 , R 1 / 2 and R 1 / 3 . The electrodes are of polysilicon, and the resistivity of polysilicon means there is a significant resistance R ( FIG. 2 ) along each electrode between the terminals t 1 to t 6 , at which the phase voltages IΦ 1 to IΦ 3 are applied, and the centre of the CCD device. The electrodes also have capacitance C to the silicon S on which the electrodes are mounted dependent on the dielectric (the silicon dioxide layer d 1 which forms at the face of the silicon) resulting in an electrical time constant. The effect of this time constant would be to reduce the amplitude of the varying clock voltage at the horizontal centre of the device as the speed of the parallel transfer is increased.
[0029] Zig-zag strips of metal mP 1 , mP 2 , mP 3 , mP 5 , mP 6 , mP 7 , etc are provided to reduce the time constant of voltage variation at the centre of the electrodes, which can be closely spaced and driven only at the sides of the array.
[0030] The first row has a terminal t 1 connected to the first voltage phase IΦ 1 . The second row has a terminal t 2 connected to the second voltage phase IΦ 2 . The third row has a terminal t 3 connected to the third voltage phase IΦ 3 . The fourth row does not have a terminal, and the next terminal t 4 for the first voltage phase IΦ 1 is provided on the next row in order to avoid the need to have the terminal for the IΦ 1 phase immediately adjacent to the terminal for the IΦ 3 phase. All terminals IΦ 1 etc are commonly driven by the respective voltage phase as shown in FIG. 4 .
[0031] In order that each electrode of each row is supplied with the required phase voltage, each strip mP 1 , mP 2 , mP 3 , mP 5 , mP 6 , mP 7 connects to a respective terminal t 1 to t 6 and makes electrical connection with the electrodes which are driven at corresponding phases in four rows. For example, the conducting strip mP 1 connected to terminal t 1 driven by phase IΦ 1 makes electrical contact with the phase IΦ 1 electrodes in the four rows, R 1 / 1 , R 2 / 1 , R 3 / 1 and R 4 / 1 . Successive portions of the strips of metal, for example, of mP 1 , are inclined to the rows in repeatedly reversing directions and make multiple connections to each polysilicon electrode of the respective voltage phase along its length.
[0032] The electrical connections of the strips mPn to the polysilicon electrodes Rn/n is achieved by etching through regions of the insulating silicon diode layer d 2 which forms on the polysilicon electrodes Rn/n ( FIG. 2 ). A thin layer of metal is then deposited all over the wafer, and etched away where unwanted leaving the continuous zig-zag pattern of the conducting strips mPn. Shallow square depressions in the strips are visible over the etched away regions, indicating the contact regions from the metal tracks to the electrodes below, typical ones of which are indicated by the reference ‘a’. Each metal conductor makes contact with the associated polysilicon electrodes at frequent intervals across the CCD device, typically hundreds of times.
[0033] The embodiment of FIGS. 3 and 4 uses three phase image clocks, but the technique is also applicable to CCDs with other numbers of phases, such as two phase and four phase. Typically the vertical pitch of the metal tracks will be a multiple of the pitch of the electrodes and the angles of the zigzag to the horizontal optimised according the sensor requirements such as horizontal and vertical pixel size (pixels are not necessarily square) and the number of parallel transfer electrodes defining each pixel.
[0034] Since the metal tracks may reflect light that passes all the way through the silicon (mainly of concern for red or infra-red light that penetrates silicon more deeply) increasing the likelihood of capture of photons, the width and angle of the tracks may be chosen to help equalise the amount of metal over each pixel and hence reduce the variation in sensitivity from pixel to pixel.
[0035] It is in general desirable for the zigzag metal track not to extend over more vertical electrodes than necessary since the metal track will be longer, increasing its resistance, and there may be fewer contacts from the metal track to the corresponding polysilicon electrodes.
[0036] A typical CCD with traditional straight metal tracks of the kind shown in FIG. 1 having a maximum parallel transfer speed of at least 10 MHz (compared to a parallel transfer speed of 2 MHz without metal tracks) can be made with a minimum pitch of pixel in the column direction of 30 micrometres. A CCD with zig-zag metal tracks according to the invention can maintain the same speed of transfer with a much smaller pixel pitch, for example, 12 micrometres. The zig-zag metal tracks could have a width of as little as 8 microns, spaced by as little as 6 microns.
[0037] Variations may of course be made to the described embodiment without departing from the scope of the invention. Thus, the zig-zag could include flat sections at the tops and bottoms of the zig-zag, the angles of the zigzag sections could vary along the length of the rows, or the strips could undulate in a continuous fashion, for example, sinusoid-shaped metal strips could be used. The terminals for the phase voltages could be provided at every fourth row, instead of every fifth row as illustrated. Adjacent terminal connections could be avoided by splitting them between opposite sides of the array. Equally, terminals could be provided at every sixth row, or at a greater interval, by arranging that the conducting strips extend over and make electrical connection with a greater number of rows. Equally, more than one strip could be provided per each row, for example, two strips could be provided per three electrodes, as long as there are less metal tracks than electrodes. Materials other than aluminium could be used for the conducting strips, for example, copper. Also, there is no need for the electrodes to be of polysilicon, they could be of other materials. There is also no requirement for the CCD to have a silicon substrate.
[0038] Referring to FIGS. 2 , 5 and 6 , a frame transfer CCD is shown according to a second embodiment of the invention. FIG. 5 shows rows of pixels on each side of the transition between image region and store region, namely, Pi 1 , 1 , Pi 2 , 1 , Pi 3 , 1 , Pi 4 , 1 , Pi 5 , 1 and Pi 6 , 1 in the image region 2 and Ps 1 , 1 , Ps 2 , 1 in the store region 4 . FIG. 5 shows twelve columns (up to Pi 1 , 12 ) while FIG. 6 shows just two. In section, the CCD is the same as the prior art CCD of FIG. 2 . In commercial devices, there would be hundreds of rows in the image region, for example, 1024 rows by 1024 columns in the image area, and typically slightly more rows in the store region. Each bottom row of the store region 2 is transferred to an output register 3 , which has a serial output in the direction of the arrow A.
[0039] In such CCDs, the image region and store region of the CCD are operated by different clocking waveforms, the image region 2 by three phase image clocks (IΦ 1 , IΦ 2 and IΦ 3 ) and the store region 4 is clocked by three phase store region clocks (SΦ 1 , SΦ 2 and SΦ 3 ). Typically, the image and store region phase clocks would be such as to shift the charge pattern in the image region rapidly into the store region, to avoid frame transfer smear. The readout from the store region will typically take much longer, since this can take place over one integration period in which a frame is exposed in the image region. A typical shift from the image region to the store region would take place in approximately 0.1 ms, while readout from the store region would typically take 20 ms.
[0040] There will be occasions when the store clocks and the image clocks have different voltages applied to them, such as during an integration period where the image clocks will be held at fixed potentials, while the store clocks will be transporting the charges to the output register 3 , from each row to the adjacent one.
[0041] In the second embodiment of the invention, the zigzag pattern extends vertically over a greater number of rows than in the first embodiment (six rows instead of four rows). The metal strips are mPi 1 , mPi 2 , mPi 3 for the image region and mPs 1 , mPs 2 , mPs 3 for the store region. Each strip connects to the relevant phase voltages at terminals t 1 to t 6 . It will be noted that the conducting strips which extend over the last two rows of the image region 2 and the first row of the store region 4 are connected to both image and store clocks. However, the conducting strips mPs 1 and mPs 2 connected to the store clocks do not make electrical connection to the electrodes of the last two rows of the image region 2 . This avoids a short between corresponding image and store clocks. During frame transfer, both image and store clocks operate in synchronism. During integration, the store clocks operate while the image clocks do not.
[0042] Similar constraints will apply to CCDs with other numbers of phases in the image and store regions.
[0043] In the second embodiment of the invention, the image region and the store region are adjacent to each other. However, there may be a pipelined connection between them. Thus, a CCD could be constructed with one image section with two (or more) store sections beneath, each section with its own set of clocks. The advantage is that two images could be captured quickly, the first moved down to the lower of the two store sections and the second moved down to the upper of the two store sections. The two images, captured close together in time, can then be read out at normal speed. There would be multiple boundaries where the clocks must change over to a different set (e.g. image to store 1 and also store 1 to store 2 in this example).
[0044] Further, the invention is not only applicable to full frame CCDs, as in the first embodiment, or frame transfer CCDs, as in the second embodiment, it also applies to interline transfer CCDs and TDI CCDs, or other CCDs employing parallel transfer. While the CODs described above have all had straight electrodes, the invention is also applicable to CCDs with curved electrodes.
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A back-illuminated CCD includes a two-dimensional array of charge collection sites arranged in rows and columns. Each row is associated with a plurality of electrodes at the front face extending in the direction of the row and corresponding to respective phase voltages. A plurality of conducting strips is provided with each strip having repeatedly reversing inclined portions. Each portion is in electrical contact with the electrodes of a corresponding phase voltage of two or more rows. Each portion is inclined relative to the rows in the opposite direction to that in which the preceding portion is inclined.
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BACKGROUND OF THE INVENTION
It is known, and desirable, to construct jacquard controlled warp knitting machines comprising two yarn guide members which are influenced by the appropriate jacquard droppers. The construction costs of providing the second row of yarn guides is substantial. In machines which additionally utilize drop plates in which the jacquard guide bar must be provided in front of the dropping plate, the provision of a second set of jacquard controlled guides and dropper pins is very complicated since the provision of the thread for the second jacquard guide bar must in every case pass through the first bar.
It is also known to construct warp knitting machines having two sets of yarn guide members on a single guide bar. In these machines, however, the orientation of the thread bearing eyelets of the guides in the uninfluenced condition is separated by a needle space so that in the uninfluenced condition only one guide will pass between any predetermined pair of needles.
It would be most desirable to provide equipment wherein several guide members could pass, at the same time, through the space between any predetermined pair of needles in the jacquard uninfluenced condition or, alternatively, in the influenced position be able to knit across more than one adjacent needle.
SUMMARY OF THE INVENTION
In the present invention, there are provided yarn guide units wherein at least two yarn guide heads may pass, in the jacquard uninfluenced condition, between any predetermined pair of needles on the appropriate needle bar of the warp knitting machine. In the present invention, the head portion of at least one guide member of adjacent guides is displaced laterally, but with its plane parallel to the plane of its shaft portion so that at least two adjacent guide head portions having the thread eyelets in the ends thereof lie in a single plane and are enabled to pass, in the uninfluenced condition, between any predetermined pair of needles. This arrangement permits the use of a single jacquard influenced guide bar influenced by jacqeyelets in the ends thereof lie in a single plane and are enabled to pass, in the uninfluenced condition, between any predetermined pair of needles. This arrangement permits the use of a single jacquard influenced guide bar influenced by jacquard dropper pins to be used in the production of double colored or double threaded jacquard patterns. In this equipment each of the guide members is influenceable to the extent that it is able to make an overlap over one working needle while, at the same time, an underlap is carried out on an adjacent needle.
In a further embodiment of the present invention, the guides are provided in pairs of guide members wherein the distance between the shaft portions of each adjacent guide member is half the distance between any pair of needles. The head portions of the adjacent guide members in a given guide are laterally displaced towards each other so that the head portions lie in a single plane. The distance between adjacent pairs of head portions is equivalent to the distance between adjacent pairs of needles.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial plan view of a yarn guide unit showing the alternation of pairs of yarn guides. It further shows the location of the general plane AA--AA of the mounting unit.
FIG. 2 is a side elevational view of FIG. 1 viewed from 2--2 further including an indication of the plane BB--BB to which the side elevational view of the planes of the face of the yarn guides of the preferred embodiment of the present invention lie parallel.
FIG. 3 is a side elevational perspective view of FIG. 2 showing the location of the transverse axis A within the principal plane AA--AA of the mounting units.
In all the foregoing figures, which indicate the at rest position of the yarn guides, said yarn guides are, during the operation thereof in the warp knitting machine, influenced from side J-1 to side J-2 by jacquard dropper pins which contact on side J-1. The dotted line qq in FIG. 1 indicates an arbitrary line of demarcation between the shaft portion of the guide and the central portion, and the dotted line pp indicates an arbitrary line of demarcation between the central portion and the head portion of the guides.
In the discussion of the preferred embodiments set forth hereinbelow, the last two digits of two or three digit numbers indicates the same part or portion of the overall device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In all the embodiments of the present invention, there is provided a conventional mounting unit 10. There are also provided a plurality of yarn guides 20. Also illustrated in dotted form are the locations 15 of the needles in the appropriate needle bars 16.
The mounting units 10 have a general plane designated AA--AA. Further, FIG. 3 shows a transverse axis A' of said mounting unit. The transverse axis is an arbitrary line approximate to the mounting hole 16 passing through the mounting unit 10 parallel to edges 17 and 19 which provide between them the face in which the guides 20 are mounted, suitably soldered, in the conventional manner.
FIG. 2 further shows an axial plane BB--BB. This is a theoretical plane. In the embodiments shown, the flat elongated head portions 21 and 24 of the yarn guide members 22 and 22' lie parallel to this plane, the longitudinal axes of the flat elongated head and shaft portions of guide members 22 and 22' lie parallel to this plane and said plane is perpendicular to the general plane AA--AA of the mounting unit 10.
In the preferred embodiments of the invention the, shaft portion 12 of a guide member 22 is mounted in mounting unit 10 in any given set of guides 20. At least one member 22 thereof has its central portion 25 bent towards an adjacent guide member 22', and the elongated head portion 24 thereof, having eyelet 27 in the end thereof, oriented with its plane parallel to the shaft portions 12 and 112. Alternatively, member 22' may have its central portion 125 bent towards an adjacent guide member 22 and the elongated head portion 124 thereof, having eyelet 127 in the end thereof, oriented with its plane parallel to the shaft portions 12 and 112. It will be seen by those skilled in the art that many variations are possible.
In the embodiment shown in FIG. 1, adjacent guides are bent towards each other so that the plane of the elongated head portions 24 and 124 lie in a single plane and said plane lies substantially halfway between the planes on which the respective shaft portions 12 and 112 lie. It is, of course, possible to maintain, say, an entire guide member in a single plane and to displace the head portion 124 of an immediately adjacent guide 22', on one side all the way across the space between the adjacent guide members so that, say, shaft portion 12 (but not shaft portion 112) and head portions 24 and 124 all lie in a single plane.
In a further embodiment a third guide member lying on the other side of the unbent guide member (entire member in a single plane) could be similarly displaced in the full gap amount (space between adjacent guide member) to provide three head portions lying in a single plane. It will, thus, be seen that the invention is not limited to the number of guides members in a yarn guide.
In the especially preferred embodiment of the invention illustrated in FIG. 1, the space between needles 15 in the appropriate needle bed is shown as b. The space between adjacent shaft portions of guide members 22 and 22' is shown as a. The displacement of the head portions 24 and 124 laterally from the corresponding shaft portions 12 and 112 is onehalf a. In this embodiment 2a equals b; thus, the distance between the head portions of adjacent sets of guide members from each other is equal to b and the distance of each head portion from the adjacent shaft portion is onehalf a.
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There are provided jacquard controlled warp knitting machines equipped with yarn guide units having yarn guides wherein the heads of said yarn guide members are so oriented that, when uninfluenced by the jacquard dropper pins, two or more yarn guide member heads may pass between any predetermined pair of needles on the needle bar of the machine.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of, and claims the benefit of the filing date of, U.S. patent application Ser. No. 11/204,413 entitled “A QUEUE DESIGN SYSTEM SUPPORTING DEPENDENCY CHECKING AND ISSUE FOR SIMD INSTRUCTIONS WITHIN A GENERAL PURPOSE PROCESSOR”, filed Aug. 16, 2005 now U.S. Pat. No. 7,328,330.
FIELD OF THE INVENTION
The present invention relates generally to a queue design for SIMD instructions, and more particularly, to an independent queue design supporting dependency checking for SIMD instructions that share most of the front-end of the processor pipeline with a General Purpose instructions.
DESCRIPTION OF THE RELATED ART
Modern processors support single instruction multiple data (“SIMD”) extensions. SIMD indicates a single instruction that operates on a number of data items in parallel. For example, an “add” SIMD instruction may add eight 16 bit values in parallel. These instructions increase execution speed dramatically by accomplishing multiple operations within one instruction. Examples of these SIMD instructions include multimedia extension (“MMX”) instructions, SSE instructions, and vectored multimedia extension (“VMX”) instructions.
There are a few general problems associated with SIMD instructions that lead to an increase in execution latency and a failure to efficiently utilize resources for a processor. For example, many of the SIMD arithmetic instructions are complex and may take many cycles to execute. Each SIMD load and store instruction may take hundreds of cycles to complete due to the memory latency if they miss in the cache memory. For loads and stores, these SIMD instructions will stall their data depended SIMD instructions until their completion. In many modern superscalar pipeline processor designs, the SIMD Unit and the General Purpose (“GP”) Unit may share their dependency checking, issue, dispatch, and decode pipeline stages. Therefore, the data dependency and memory latency conditions of these SIMD instructions can also stall the non-related GP instructions (such as PowerPC instruction and x86 instructions) as well because some of the GP instructions can exist behind the depended SIMD instructions in a program flow. This stall condition not only extends the overall execution latency of the program but also causes some of the execution Units, such as a GP Unit to be idle. This leads to a detrimental affect on the overall processor performance.
Complicated SIMD instructions should not affect the execution of GP instructions. Although SIMD instructions provide a distinct advantage, problems associated with SIMD instructions can affect the overall performance of the processor. An invention that can isolate the problems associated with SIMD instructions and not allow these problems to affect execution of GP instructions would be a vast improvement over the prior art.
SUMMARY OF THE INVENTION
A processor includes a general purpose (GP) unit adapted to receive GP instructions and configured to execute the GP instructions. The processor also includes a single instruction multiple data (SIMD) unit adapted to receive SIMD instructions and configured to execute the SIMD instructions. An instruction unit comprises a first logic unit coupled to the GP unit and a second logic unit coupled to the SIMD unit, wherein SIMD instructions are processed subsequent to GP instructions. The first logic unit is further configured such that a GP instruction with unresolved dependencies unconditionally causes subsequent SIMD instructions to stall, and an SIMD instruction with unresolved dependencies does not cause subsequent GP instructions to stall. The first logic unit is coupled to receive GP instructions and SIMD instructions and configured to: decode the GP instructions and the SIMD instructions; check the GP instructions for dependencies; resolve any dependencies in the GP instructions; provide the GP instructions that are free of dependencies to the GP unit; and subsequent to providing the GP instructions that are free of dependencies to the GP unit, provide the SIMD instructions to the second logic unit when there are no remaining older GP instructions with dependencies; wherein the first logic unit is not configured to check the SIMD instructions for dependencies. The second logic unit is coupled to receive the SIMD instructions from the first logic unit and, subsequent to providing, by the first logic unit, the GP instructions that are free of dependencies to the GP unit, configured to: check the SIMD instructions for dependencies; resolve any dependencies in the SIMD instructions; and provide the SIMD instructions that are free of dependencies to the SIMD unit.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram of a processor;
FIG. 2 is a block diagram illustrating an instruction Unit, an SIMD Unit, a GP Unit, and an L2 cache;
FIG. 3 is a block diagram illustrating an instruction pipeline within an instruction Unit connected to an SIMD Unit, a Branch Unit, and a GP Unit; and
FIG. 4 is a flow chart depicting the separate execution of SIMD instructions and GP instructions in a modified processor.
DETAILED DESCRIPTION
In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present invention in unnecessary detail. Additionally, for the most part, intimate details concerning network communications, electro-magnetic signaling techniques, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present invention, and are considered to be within the understanding of persons of ordinary skill in the relevant art.
It is further noted that, unless indicated otherwise, all functions described herein may be performed in either hardware or software, or some combination thereof. In a preferred embodiment, however, the functions are implemented in hardware in order to provide the most efficient implementation. Alternatively, the functions may be performed by a processor such as a computer or an electronic data processor in accordance with code such as computer program code, software, and/or integrated circuits that are coded to perform such functions, unless indicated otherwise.
FIG. 1 is a block diagram of a processor 100 . Instruction controller 102 controls the flow of data into and out of the processor 100 . Instruction controller 102 sends control signals to aid in the operation of Instruction Unit 104 . Instruction Unit 104 issues the instructions that will be executed. Instruction Unit 104 issues SIMD instructions to SIMD Unit 106 and GP instructions to GP Unit 108 . SIMD Unit 106 and GP Unit 108 are execution units that execute SIMD and GP instructions, respectively. There is an interface between SIMD Unit 106 and GP Unit 108 because SIMD Unit 106 may need to retrieve data results from GP Unit 108 and GP Unit 108 may need to retrieve data results from SIMD Unit 106 . The L2 cache 110 can store instructions and data results. GP Unit 108 retrieves data from L2 cache 110 when necessary to execute instructions. Instruction Unit 104 also retrieves instructions from L2 cache 110 in order to execute program code. Instruction controller 102 sends signals to aid in the storage and retrieval of data to or from L2 cache 110 . Processor 100 may contain many other components that are not shown in FIG. 1 . FIG. 1 is a basic representation of a processor and does not limit the scope of the present invention.
FIG. 2 is a block diagram 200 illustrating an Instruction Unit 104 , an SIMD Unit 106 , a GP Unit 108 , and an L2 cache 110 . Instruction Unit 104 is a functional unit that is able to decode and execute specific instructions. Accordingly, Instruction Unit 104 contains many components to assist with decoding and executing these instructions. L2 cache 110 stores instructions and/or data results that are used by GP Unit 108 for execution. Within Instruction Unit 104 , the instructions enter the instruction pipelines with instruction pre-decode 206 . The path of instructions through the operation blocks 206 , 208 , 212 , 214 , 216 , and 218 , are the instruction pipelines. After the instructions are pre-decoded, L1 instruction cache 208 stores the instructions before they are sent to the instruction buffers 212 . L1 instruction cache 208 also stores instructions and data results on the Instruction Unit 104 to enable quick access and/or later retrieval.
Before the instructions are sent to the instruction buffers 212 , operation block 204 accomplishes many operations, such as instruction fetch, branch prediction, branch history, and address translation. These operations are commonly known in the art, and enable Instruction Unit 104 to operate efficiently. Operation block 204 also signals L1 instruction cache 208 to take branches and store other data when necessary. The instruction buffers 212 contain two threads (A and B). A thread is a program or a group of instructions that can execute independently. Microcode engine 210 reads the group of instructions from the threads (A and B) and controls multiplexer (“MUX”) 214 accordingly. MUX 214 dispatches the instructions from the instruction buffers 212 . Normally, MUX 214 dispatches instructions from thread A and thread B in equal distribution. The decode pipelines, some of the issue pipelines and some of the dispatch pipelines are referred to as “front end” pipelines. Accordingly, operation blocks 204 , 206 , 208 , 210 , 212 , and 214 would be considered “front-end” pipelines in FIG. 2 .
Operation block 216 further decodes the instructions and checks GP instructions for dependencies. Operation block 218 stalls the instructions and subsequently issues the instructions to the execution units. The stall enables Instruction Unit 104 to ensure that the issued instructions are valid and able to be executed. If an instruction is incorrect or contains a dependency then Instruction Unit 104 flushes the incorrect instruction and subsequent dependent instructions. By flushing the instructions to an earlier portion of the instruction pipelines, Instruction Unit 104 ensures that any exceptional conditions can be resolved before the instructions are issued. In the present invention Instruction Unit 104 does not check the SIMD instructions for dependencies until after the instructions are issued by operation block 218 .
Operation block 218 transmits the instructions down three separate paths depending upon the type of instruction. In one embodiment, operation block 218 transmits GP instructions (two at a time) to GP Unit 108 , branch instructions (one at a time) to Branch Unit 222 , and SIMD instructions (two at a time) to operation block 220 . Alternative embodiments can employ different widths of instruction dispatch and issuance. Operation block 220 and Branch Unit 222 reside on Instruction Unit 104 . GP Unit 108 executes the GP instructions. Branch instructions are commonly known in the art and enable Instruction Unit 104 to operate more efficiently. Operation block 220 queues the SIMD instructions and checks the instructions for dependencies. A stall for operation block 220 allows Instruction Unit 104 to check for dependences before issuing the SIMD instructions. Operation block 220 issues the SIMD instructions to SIMD Unit 106 . FIG. 2 depicts one embodiment of the present invention, and does not limit the present invention to this embodiment.
FIG. 3 is a block diagram illustrating an instruction pipeline within an instruction Unit connected to an SIMD Unit, a branch Unit, and a GP Unit. FIG. 3 represents the same instruction Unit 104 of FIG. 2 without the “front end” operations (a common term in the art representing the instruction handling portion of the pipeline). Accordingly, the SIMD instructions and the GP instructions share the “front end” of the pipelines for Instruction Unit 104 . Operation block 216 decodes the instructions and determines whether the instruction is an SIMD instruction, a branch instruction, or a GP instruction. Operation block 216 checks GP instructions for dependencies, but does not check SIMD instructions. Therefore, the SIMD instructions continue through the instruction pipelines without being checked for dependencies. The stall at operation block 218 enables instruction Unit 104 to resolve dependencies with the GP instructions through the use of a pipeline flush or other mechanism. Accordingly, only GP instructions can trigger a pipeline stall at this point 218 .
Operation block 218 sends GP instructions to GP Unit 108 on communication channel 302 , branch instructions to branch Unit 222 on communication channel 304 , and SIMD instructions to operation block 220 on communication channel 306 . Operation block 220 accomplishes the same operations as operation blocks 216 and 218 , but with SIMD instructions instead of GP instructions. The stall at operation block 220 enables Instruction Unit 104 to resolve dependencies with the SIMD instructions through the use of a pipeline stall. Instruction Unit 104 flushes the incorrect instructions to the “front end” of the instruction pipelines (as described with reference to FIG. 2 ) in the event of an exceptional condition or a branch misprediction. Operation block 220 sends the valid SIMD instructions to SIMD Unit 106 for execution on communication channel 308 . Communication channel 310 provides an interface between SIMD Unit 106 and GP Unit 108 . Accordingly, FIGS. 2 and 3 are provided as an example of the configuration of Instruction Unit 104 in the present invention and do not limit the present invention to this configuration.
The advantage of the present configuration 300 is that the dependency checking for GP instructions is completely separate from the dependency checking for SIMD instructions. The dependency checking of SIMD instructions is after the issuance of GP instructions to GP Unit 108 . The SIMD issue queue in operation block 220 is completely independent from the execution of GP instructions. In conventional processors a dependency with an SIMD instruction leads to a latency with subsequent GP instructions within the instruction pipelines. Accordingly, a pipeline stall due to an SIMD dependency stalls the subsequent GP instructions. Therefore, conventional instruction units experience an unnecessary latency for GP instructions. By removing dependency checking for SIMD instructions within the shared pipeline, instruction Unit 104 operates more efficiently with regard to GP instructions. This advantage persists until operation block 220 is filled with instructions due to a SIMD dependency or other stalling condition. When operation block 220 is full, operation block 218 will stall if a SIMD instruction is encountered in order to prevent overflowing the SIMD issue queue on operation block 220 . This condition will stall both SIMD instructions and GP instructions. The condition is rare and can be improved by increasing the size of the SIMD issue queue on operation block 220 .
The separation of SIMD and GP instructions in the present invention provides many advantages. The physical location of SIMD Unit 106 can be separate from GP Unit 108 because the SIMD issue queue covers the latency between Units. This enables more modular and flexible chip designs, and also simplifies the design of GP Unit 108 . The SIMD issue queue and SIMD Unit 106 also helps with timing issues within the processor by simplifying the complicated dependency logic. Furthermore, through the use of operation block 220 (SIMD issue queue and SIMD dependency checking) the latency of SIMD load instructions is hidden to SIMD Unit 106 . This leads to better performance for SIMD Unit 106 by allowing SIMD instructions to compute in parallel and out-of-order with respect to GP instructions.
This configuration 300 requires the proper control coordination between SIMD Unit 106 and GP Unit 108 to function properly. In a preferred embodiment, a compiler working in conjunction with the necessary control logic (not shown) controls the operation of this instruction Unit 104 through the use of programmable software. The compiler determines which instructions are SIMD and which instructions are GP at operation block 216 . Then, the compiler ensures the validity of GP instructions and SIMD instructions at the stall points of operation block 218 and operation block 220 , respectively. Accordingly, the compiler controls the transmission of SIMD instructions on communication channel 306 , branch instructions on communication channel 304 , and GP instructions on communication channel 302 . The compiler optimizes for exceptional conditions and instruction flushing at operation block 216 for GP instructions and operation block 220 for SIMD instructions. Communication channel 310 also enables the compiler to control the load and store communication between SIMD Unit 106 and GP Unit 108 .
FIG. 4 is a flow chart 400 depicting the separate execution of SIMD instructions and general purpose instructions in a modified processor. First, Instruction Unit 104 stages all of the instructions (SIMD and GP) through the instruction pipeline 402 . Instruction Unit 104 decodes all of the instructions and checks for dependencies with the GP instructions 404 . Instruction Unit 104 may need to resolve GP instruction dependencies before the instructions are issued. Instruction Unit 104 stalls all of the instructions (SIMD and GP) if a stall condition occurs and then issues the instructions to the respective execution units 406 . Accordingly, the GP instructions go to GP Unit 108 , and SIMD instructions go towards the SIMD Unit 106 . Instruction Unit 104 queues the SIMD instructions and checks for dependencies 408 . Accordingly, the SIMD instructions remain within Instruction Unit 104 until they are issued to the SIMD Unit 106 . Instruction Unit 104 stalls the SIMD instructions and then issues these instructions to the SIMD Unit 410 . SIMD Unit 106 executes the SIMD instructions 412 . Independently, the GP Unit 108 executes the GP instructions 414 . It is clear that an instruction unit and ultimately a processor operates more efficiently if the SIMD instructions and the GP instructions can share the same resources, but execute independently. Therefore, SIMD instruction dependencies do not affect the performance of the processor with regard to GP instructions.
It is understood that the present invention can take many forms and embodiments. Accordingly, several variations of the present design may be made without departing from the scope of the invention. This invention can apply to any processor design that has a complex/long pipeline execution unit, such as an SIMD unit and a simple/short pipeline execution unit, such as a GP unit. The capabilities outlined herein allow for the possibility of a variety of networking models. This disclosure should not be read as preferring any particular networking model, but is instead directed to the underlying concepts on which these networking models can be built. The purpose of the present invention is to minimize the delay of simple execution instructions that are caused by complex execution instructions.
Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.
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A processor includes a general purpose (GP) unit adapted to receive and configured to execute GP instructions; and includes a single instruction multiple data (SIMD) unit adapted to receive and configured to execute SIMD instructions. An instruction unit comprises a first logic unit coupled to the GP unit and a second logic unit coupled to the SIMD unit, wherein SIMD instructions are processed subsequent to GP instructions. In the first logic unit a GP instruction with unresolved dependencies unconditionally causes subsequent SIMD instructions to stall, and an SIMD instruction with unresolved dependencies does not cause subsequent GP instructions to stall. The first logic unit resolves dependencies in GP instructions, provides dependency-free instructions to the GP unit, and provides SIMD instructions to the second logic unit. The second logic unit resolves dependencies in SIMD instructions and provides dependency-free instructions to the SIMD unit.
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BACKGROUND OF THE INVENTION
One of the more serious problems confronting a manufacturer of polyesterurethanes and manufacturers of parts prepared from polyesterurethanes is that degradation takes place over a period of time when conditions are such that hydrolysis can result. This degradation generally occurs at the ester linkage. Various techniques have been utilized in order to improve the stability of polyesters against hydrolysis. One such technique is to incorporate into the polyester either chemically or mechanically, compounds such as carbodiimide, alkylene carbonates, silicones and 2-imino-oxazolidines (see, e.g., U.S. Pat. Nos. 3,401,144 and 3,770,693).
Additionally, since many thermoplastic polyurethanes based on polyesters will ultimately discolor, only mild interest has been displayed in the past in providing products with low initial color. Whenever possible, care was taken to minimize color of the reactants, but to date, the thermoplastic polyesterurethanes themselves have not been assigned any color specifications. Recently, there has developed a market for colorless, transparent roller skate wheels molded from thermoplastic polyurethanes. The specific type of discoloration involved is that which occurred during exposure of the thermoplastic polyesterurethane to processing temperatures experienced during drying, extrusion or molding. The yellowing of the polymer did not seem to be associated with any significant change in strength properties and was entirely different from the discoloration which occurs during the service life of the ultimate product (i.e., weathering). It was found that this discoloration could occur during pelletization extrusion, resulting in the shipment of pellets which varied in color. It was also found that some lots of polymer discolored even more during the final product processing with the result that the final product also varied in color.
DESCRIPTION OF THE INVENTION
It has now been found that the hydrolytic stability and discoloration problems noted above can be substantially eliminated by adding to the thermoplastic polyurethanes before, during or after the polymer-forming reaction, small amounts of 2-oxazolidones. Additionally, and quite unexpectedly, the oxazolidones described herein, when added to the thermoplastic polyurethane are effective color stabilizers.
The preferred 2-oxazolidones are generally known and correspond to the formula: ##STR1## WHERE R represents hydrogen or an organic radical which is free of epoxide reactable groups, such as an aliphatic, aromatic, mixed aliphatic-aromatic, or an organic polymer radical; X 1 and X 2 may be the same or different and represent hydrogen or organic radicals which are free of epoxide reactive groups; and n represents an integer of 1 to 3. As is known in the art, these oxazolidones may be produced in a number of ways, e.g. (a) by reacting an organic isocyanate with an epoxide, (b) by reacting the corresponding isocyanate dimer with an epoxide, or (c) by reacting an organic isocyanate with an alkylene carbonate. It is generally preferred that R, X 1 and X 2 each represent a hydrogen atom or a radical selected from the group consisting of alkyl and cycloalkyl of from 1 to 12 carbon atoms and aryl, aralkyl and alkaryl of from 6 to 15 carbon atoms and n represents an integer of from 1 to 3. It is preferable that X 1 and X 2 each represent hydrogen. In addition to hydrogen, R can preferably represent, e.g., one of the following: methyl, ethyl, propyl, isopropyl, cyclohexyl, phenyl, tolyl biphenyl and the like. It is presently most preferred that when n = 1, R represents H, ##STR2##
As noted above, the 2-oxazolidones useful in the instant invention are generally known and have been described, e.g., in U.S. Pat. Nos. 2,977,369; 2,977,370; 2,977,371; and 4,022,721, and in "HETEROCYCLIC COMPOUNDS", VOLUME 5, "Five-Membered Heterocycles Containing Two Hetero Atoms and Their Benzo-Derivatives", edited by Robert C. Elderfield, 1957, pages 396 through 402, the disclosures of which are herein incorporated by reference.
The oxazolidones should be added to the thermoplastic polyurethanes in amounts effective to stabilize the polyurethane and preferably in amounts ranging from 0.02 to 6 percent by weight based on the total weight of the polyurethane. It has been surprisingly found that when these amounts are used, in addition to improved stability against processing discoloration, the polyurethanes exhibit greatly improved hydrolytic stability.
In practicing the invention, the oxazolidone can be added to the polyester, the organic isocyanate or other reactant used in the preparation of the polyesterurethane, such as, a chain extender, or it may be added to the polyesterurethane product. Addition to the product itself is generally most practical. The addition can be made in the dissolved state, by extruding, milling, stirring or any suitable technique.
In the preparation of polyesterurethanes, any suitable polyester may be used, such as those prepared from polycarboxylic acids and polyhydric alcohols. Any suitable polycarboxylic acid may be used such as, for example, benzene tricarboxylic acid, adipic acid, succinic acid, suberic acid, sebacic acid, oxalic acid, methyladipic acid, glutaric acid, pimelic acid, azelaic acid, phthalic acid, terephthalic acid, isophthalic acid, thiodipropionic acid, maleic acid, fumaric acid, citraconic acid, itaonic acid and the like.
Any suitable polyhydric alcohol may be used as, for example, ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, bis-(hydroxy methyl chlorohexane), diethylene glycol, 2,2-dimethyl propylene glycol, 1,3,6-hexanetriol, trimethylol propane, pentaerythritol, sorbitol, glycerine and the like. Also, suitable as polyesters in the preparation of polyesterurethanes are those prepared from lactams, lactones, polyesteramides, and the like.
In the preparation of polyesteramides, an amine is included in the reaction of a carboxylic acid and an alcohol, aminoalcohol or aminoacid can be used. Any suitable amino compound can be used to prepare polyesteramides such as, for example, hexamethylene diamine, ethylene diamine, propylene diamine, butylene diamine, cyclohexyl diamine, phenylene diamine, tolylene diamine, xylylene diamine, 4,4'-diamino-diphenylmethane, naphthylene diamine, aminoethyl alcohol, aminopropyl alcohol, aminobutyl alcohol, aminobenzyl alcohol, aminoacetic acid, aminopropionic acid, aminobutyric acid, aminovaleric acid, aminophthalic acid, aminobenzoic acid and the like. Of course, the amino compounds may be reacted either simultaneously with the ester forming components or sequentially therewith.
Any suitable polyisocyanate can be used in the preparation of polyesterurethanes by reaction with a polyester such as, tetramethylene diisocyanate, hexamethylene, diisocyanate, 1,4-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, 2,6-tolylene diisocyanate, 3,5-tolylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 1-methoxy-2,4-phenylene diisocyanate, 1-methyl-3,5-diethyl-2,6-phenylene diisocyanate, 1,3,5-triethyl-2,4-phenylene diisocyanate, 1-methyl-3,5-diethyl-2,4-phenylene diisocyanate, 1-,ethyl-3,5-diethyl-6-chloro-2,4-phenylene diisocyanate, 6-methyl-2,4-diethyl-5-nitro-1,3-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4,6-dimethyl-1,3-xylylene diisocyanate, 1,3-dimethyl-4,6-bis(beta-isocyanato-ethyl) benzene, 3-(alphaisocyanatoethyl) phenylisocyanate, 1-methyl-2,4-cyclohexylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-diethoxy-4,4'-biphenylene diisocyanate, 1,1'-bis-(4-isocyanatophenyl) cyclohexane, 4,4'-diisocyanato-diphenylmethane, 4,4'-diisocyanato-3,3'-dimetyldiphenylmethane, 4,4'-diisocyanato-3,3'-dichlorodiphenylmethane, 4,4'-diisocyanatodiphenyl-dimethylmethane, 1,5-naphthylene diisocyanate, 1,4-naphthylene diisocyanate, 2,4,4'-triisocyanatodiphenylether, 2,4,6-triisocyanato-1-methyl-3,5,-diethylbenzene, and the like.
The invention is particularly applicable to the stabilization of polyesterurethanes used in the manufacture of elastomers or casting resins for molded elements.
In the preparation of polyesterurethanes in accordance with the invention, any of the above-mentioned polyesters may be reacted with any of the isocyanates set forth and a chain extending agent containing active hydrogen atoms which are reactive with NCO groups and having a molecular weight less than about 500 such as, for example, water, ethylene glycol, propylene glycol, butylene glycol, 1,4-butanediol, butenediol, butynediol, xylylene glycol, amylene glycol, neopentyl glycol, 2,3-butanediol, 1,4-phenylene-bis-(b-hydroxy ethyl ether), 1,3-phenylene-bis-(b-hydroxy ethyl ether), bis-(hydroxy methylcyclohexane), hexanediol, diethylene glycol, dipropylene glycol and the like; polyamines such as, for example, ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, cyclohexylene diamine, phenylene diamine, tolylene diamine, xylylene diamine, 3,3'-dichlorobenzidene, 3,3'-dinitrobenzidene, 4,4'-metylene-bis(2-chloraniline), 3,3-dichloro-4,4'-biphenyl diamine, 2,6-diamino pyridine, 4,4'-diamino diphenyl methane, and the like, alkanol amines such as, for example, ethanol amine, aminopropyl alcohol, 2,2-dimethyl propanyl amine, 3-amino cyclohexyl alcohol, p-amino benzyl alcohol and the like; water hydrazine, substituted hydrazines such as, for example, N,N'-dimethyl hydrazine, 1,6-hexamethylene-bis-hydrazine, carbodihydrazide, hydrazides of dicarboxylic acids and disulfonic acids such as adipic acid dihydrazide, oxalic acid dihydrazide, isophthalic acid dihydrazine, thiopropionic acid dihydrazide, tartaric acid dihydrazide, 1,3-phenylene-disulfonic acid dihydrazide, omega-amino-capronic acid dihydrazide, gamma-hydroxybutyric hydrazide, bis-semicarbazide, bis-hydrazine carbonic esters of glycols such as many of the glycols heretofore mentioned and the like.
The following Examples illustrate the present invention.
Unless otherwise specified, all figures are to be understood as parts or percentages by weight.
EXAMPLES 1 THROUGH 6
About 1,000 parts of a polyester polyol (prepared from 1,4-butanediol and adipic acid having a molecular weight of about 2,000 and a hydroxyl number of 56) were reacted with about 410 parts of methylene (bis-phenylisocyanate) and about 100 parts by weight of 1,4-butane diol, by mixing the ingredients and curing in an oven for 30 minutes at 100° C. The resulting slab was then granulated.
The oxazolidones specified in the Table were added to the granulates in the amounts specified based on the weight of the product. The resultant mixture was divided into two portions, one was strand pelletized and one was injection molded into slabs.
The pellets were placed in ovens and heated for 16 hours at 110° C to develop color, after which they were rated for color stability on a scale of 1 to 10, 1 being colorless and 10 being most discolored.
The molded portions were aged at 100% relative humidity at 100° C for 2 days to cause hydrolytic decomposition, after which they were dried and tested. The percent tensile strength retained compared to the original value was used to measure the hydrolytic stability.
The results were as set forth in the Table.
__________________________________________________________________________ % ByExample Weight Color HydrolyticNumberOxazolidone Added Added Stability Stability__________________________________________________________________________1 None -- 10 302 a ##STR3## 0.05 8 30 b " 0.1 6 37 c " 0.5 6 42 d " 1.0 8 423 a ##STR4## 1.0 10 45 b " 1.0 9 c " 2.0 10 454 a ##STR5## 1.0 6 36 b " 1.0 95 a.sup.(1) ##STR6## 1.0 2 50 b " 1.0 8 c " 2.0 4 56 d " 2.0 5 44 e " 5.0 5 45 f " 1.17 8 38 g " 1.0 10 41h " 1.0 96 a ##STR7## 1.0 10 47 b " 1.0 8__________________________________________________________________________ .sup.(1) Note: ##STR8##
Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
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The instant invention is directed to novel color and hydrolytically stable thermoplastic polyester urethanes. The invention broadly consists of adding 2-oxazolidones to the components of the polyurethane, or to the polyurethane itself.
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BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to clothing and particularly to shirts and T-shirts. More particularly, the present invention relates to a T-shirt construction of a composite nature in which a graphical representation comprises a portion imprinted on the T-shirt and a structural portion affixed temporarily thereto while wearing.
2. General Background
Various expressions of art and graphics have been used to decorate clothing and shirts and particularly T-shirts. Various examples of devices have been patented which show the attachment of items to articles of clothing for various purposes.
See, for example, U.S. Pat. No. 3,484,974 entitled "Removable Identifying Characters for Clothing." That patent shows a jersey having an elongated strip which has an outer surface of a first separable fastening member, the strip being permanently secured to the clothing. A plurality of letters forming an individual's name are separably secured to the strip with the letters each having a rear surface formed of a second separable fastening member. One of the separable fastening members comprises a plurality of loop elements and the other separable fastening members comprises a plurality of resiliently deformable hook-shaped members adapted to engage the loop elements whereby the letters forming the name are secured to the strip by the separable engagement of the hooks with the loop elements.
A VELCRO fastener is used in U.S. Pat. No. 4,236,658 entitled "System for Holding Articles to Objects." In that patent a fastener device is shown which is used for attaching items such as binoculars and cameras to the clothing of the wearer.
Velcro fasteners are also used in U.S. Pat. No. 4,140,253 entitled "Gun Carrier" in order to attach a rifle or shotgun onto a strip of flexible material which is provided with belt loops so that the flexible material strip can be carried by the belt of the wearer. A mating element is affixed to the gun stock so that when the gun is held upright its stock is connected to the carrying unit through fasteners thus transferring the weight of the gun to the belt of the wearer.
A French Pat. No. 1,497,611 issued Oct. 13, 1967, provides a sign which can be affixed to a T-shirt in a removable fashion.
3. General Discussion of the Present Invention
The present invention provides a composite shirt construction in which a portion of an overall design is formed on the shirt itself and a second portion of the overall object design is in the form of a three-dimensional, removable member which affixes temporarily to the shirt. The combination provides thus a composite construction of the design, a portion of which is on the T-shirt and a portion of which is not.
The present invention thus provides a composite clothing article having a graphical representation which utilizes in part a three-dimensional structure, comprising a clothing article having on the surface thereof a graphical representation of a portion of an overall object to be displayed such as, for example, a guitar (see FIG. 1). A three-dimensional, self-supporting member (such as the guitar neck) is temporarily connectable to the shirt, with the connection completing an overall object display, the member being a portion thereof. In FIG. 1 the overall object to be displayed is a guitar. Means is provided for forming a temporary connection between the article of the clothing and the self-supporting member. In the preferred embodiment a Velcro-type fastener is used. The article of clothing is preferably a shirt. The object to be displayed can be any overall object such as a guitar, for example, with a portion of the object being formed permanently on the shirt itself such as by silk-screening and the other portion thereof being a three-dimensional portion manufactured of any self-supporting material such as foam, plastic, or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
For a further understanding of the nature and objects of the present invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawings, in which like parts are given like reference numerals and wherein:
FIG. 1 is a front view of the preferred embodiment of the apparatus of the present invention, with a user being schematically shown in phantom lines;
FIG. 2 is a side view of the preferred embodiment of the apparatus of the present invention with the user being schematically shown in phantom lines;
FIG. 3 is a exploded view of the preferred embodiment of the apparatus of the present invention showing portions thereof as being disconnected;
FIG. 4 is a top view of the removable portion of the preferred embodiment of the apparatus of the present invention;
FIG. 5 is a side view thereof; and
FIG. 6 is a sectional view taken along lines 6--6 of FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 can be seen composite clothing article 10 and more particularly shirt 12 which can be, for example, a T-shirt having silk-screened or otherwise imprinted thereon design 14. In FIG. 1 as exemplary, the design is a portion of a guitar. In FIG. 3, the designed portion 14 can be more clearly seen as member 20 which has been removed as will be described more fully hereinafter.
In FIGS. 1 and 2 a wearer 22 is shown in phantom lines.
A three-dimensional, self-supporting member 20 is removably affixed to shirt 12 by means of temporary connection means. In the preferred embodiment Velcro fasteners can be used and they are best seen in FIG. 3 as 25, 26, which would be fasteners sewed to shirt 12.
In FIG. 4, mating portions 30, 31 are shown which would be, for example, affixed by means such as gluing directly to member 20. In the embodiment of FIGS. 1-6, member 20 takes the form of the guitar neck.
Once member 20 is removed, shirt 12 can easily be washed without harm to the design which is permanently affixed thereto. Yet during use, member 20 is fastened in such a way as to complete an overall graphical representation of an object which in the case of FIGS. 1 and 2 is a guitar. The guitar neck is three-dimensional and extends laterally beyond the confines of the shirt perimeter as is shown in FIG. 1. The overall combination provides a toy or article of clothing which is quite unlike the mere representation of the article on the item of clothing itself. If the guitar, for example, of FIG. 1 were reproduced on the shirt 12 alone its side would be disproportionately small and it would not appear realistic in the eyes of a viewer. However when viewing FIG. 1, the composite design allows the guitar to be of a size and scale that it appears to be full sized and it appears that the wearer is, in fact, holding a guitar around his neck and in proximity to the torso of his body.
Variations would, of course, be possible within the teaching of the present invention.
Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.
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A T-shirt on which a graphical representation comprises a portion imprinted on the T-shirt is a design of an overall object to be displayed with a 3-dimension self-supporting structure temporarily connected to the T-shirt completing the design.
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BACKGROUND OF THE INVENTION
The invention relates to a self-sealing spin pack for a spinner head of a spinning machine for spinning endless filaments from a viscous spinning liquid at high pressure. The invention includes a spinneret holder, in which a spinneret is inserted and is covered by a filter pack, a piston-like thrust piece, axially movable in the spinneret holder, having a central channel, the top of which borders the bottom of a distributor block which has at least one channel, a top seal between the thrust piece and the distributor block, a middle seal to seal the space above the filter pack against the spinneret holder and a bottom flat ring seal for sealing the spinneret holder at the bottom.
A self-sealing spin pack and its mode of action are disclosed by EP-A2-0 300 120 and EP-B1-0 163 248. This known spin pack can also further have a distributor plate (perforated plate) between the spinneret and the filter pack, which distributor plate has a potlike shape at the top to receive the filter pack (EP-B1-0 163 248; position 27).
This known spin pack is expensive and complicated in construction and has led in factory use to considerable problems and difficulties. As a result of the top seal, a gap is formed between the top of the thrust piece and the bottom of the distributor block. As a result of high melt pressure, high extrusion pressure and high melt temperatures, a gradual deformation and loss of the seal by flow of the sealing material into this gap occur. As a result of this, a dead space is formed, in which, because of the high residence time of the melt, polymer degradation occurs. Furthermore, leakages keep occurring at this position. The same problems, that is deformation and tearing of the seal, the formation of dead spaces (stagnant zones), polymer degradation and leakage, also occur in particular at the metal membrane seal (which is furthermore expensive to manufacture) and accordingly also at the bottom seal. This known spin pack thus has in total three seals, two of which are inadequate, of which one, the metal membrane seal, is relatively expensive. A further disadvantage arises in that as a result of the membrane seal, a relatively large free space is formed below the seal, which leads to an undesirable long residence time of the spinning liquid, in particular in the case of low filament deniers, which causes an undesired change in the same, polymer degradation and the like.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to make available a self-sealing spin pack of the generic type, which overcomes the above-mentioned disadvantages, which is in particular reliably self-sealing and thus more reliable in operation, which is simpler in construction and thus cheaper and which has a smaller free space above the filter pack. This arrangement leads to a reduction in the residence time of the spinning liquid in this region. Another object of the present invention is to be able to achieve an enlargement of the filter surface area of the filter pack even when a distributor plate (perforated plate) is used.
This object is achieved according to the invention by the self-sealing spin pack of the type described in the introduction when the top seal has a tubular shape, has an internal diameter which corresponds to the diameter of the central channel of the thrust piece and of the channel of the distributor block and extends into both channels. The top of the thrust piece lies tightly against the bottom of the distributor block under operating conditions. The thrust piece has a potlike shape at the bottom for receiving the filter pack and, possibly, a distributor plate. The middle seal likewise has a tubular shape and covers and seals the annular gap between the spinneret holder and the edge of the potlike shape of the thrust piece.
The solution principle which is the basis of the invention therefore comprises designing the thrust piece movable in the spinneret holder in such a manner that annular gaps are formed at the top between the thrust piece and the distributor block and at the bottom between the thrust piece and the spinneret holder or the distributor plate. The annular gaps first extend radially from the interior to the exterior, the width of the annular gaps (gap width) possibly changing in operation. The annular gaps are each covered with a tubular seal, so that the pressurized spinning liquid causes the seals to be pressed radially outwards onto the annular gaps and thus effect a fluid-tight seal. It must be considered surprising that, even when the annular gaps enlarge or decrease as a result of an axial movement of the piston-like thrust piece in the spinneret holder, no leakages occur, even when the pressure of the spinning liquid is increased several times and reduced again. The thrust piece, as a result, is repeatedly moved axially to and fro, generally that is up and down.
In a particularly preferred design, the middle, tubular seal is the upwards- and/or downwards-pointing side of a seal having an L-shaped cross-section (angle seal). In a further preferred design, the middle, tubular seal, that is also the angle seal, is arranged above the spinneret, the top part of the seal, or the upwards-pointing side of the angle seal, extending into the potlike shape of the thrust piece.
An essential aspect of the invention lies in the fact that the sealing action of the top and middle tubular seals or of the upwards- and/or downwards-pointing side of the angle seal, is achieved in that the seals are pressed radially outwards by the high pressure of the spinning liquid (for example 50 to 80 bar) and are thus very slightly expanded. A further essential aspect is that the membrane seal is no longer required and, if an angle seal is used, only two seals are required instead of three as before, since the upwards- and/or downwards-pointing side of the angle seal carries out the sealing function of the membrane seal. From this there results additionally the fact that the space above the filter pack can now be dimensioned considerably smaller. The advantage resulting therefrom, that is a shorter residence time for the spinning liquid, has already been previously described.
As for the rest, the self-sealing action in the spin pack according to the invention is carried out in the same manner as in the known spin pack. Also in this case, with a pressure build-up in the space above the filter pack, a movement, although here slight, of the thrust piece takes place within the spinneret holder upwards by only a few tenths of a millimeter, until the top of the thrust piece lies tightly against the bottom of the distributor block. The pressure acts downwards in such a manner that the filter pack and--if present--the distributor plate (perforated plate) or the spinneret is pressed onto the bottom flat ring seal, which, if an angle seal is used, is formed by the radially inwards-pointing side of the angle seal.
In an embodiment of the invention, the optionally usable perforated plate does not have a pot shape at the top, but is also flat on the top. This leads to a significant enlargement of the filter surface area of the filter pack, which for example, can be approximately 25%, since in this case the external diameter of the filter pack corresponds to the internal diameter of the spinneret holder in the bottom region.
The filter pack can be equipped with the conventional media corresponding to the state of the art such as screens having differing mesh sizes, filter granules, for example sand, having different particle sizes, discs of sintered materials, etc. When loose filter granules are used, the distributor plate is expediently furnished on the top with a narrow border, the height of which corresponds to the bed height of the filter granule layer. Its design with respect to construction, height, selection of filter media, etc. depends on the type of the viscous spinning liquid, which can be the melt of thermoplastic polymers such as polyester, polyamide, etc., a solution, such as polyacrylonitrile in DMF solution, and others.
A material for the seals which has proved itself optimal is in particular soft aluminum, but soft iron and other easily deformable materials are also suitable. Suitable materials are those which can endure for long periods even the possibly high temperatures of the spinning liquid, which in the case of polymer melts can be, for example, up to 450° C.
The central channel in the thrust piece can have the same diameter or cross-section over its entire length, but can also have a diameter or cross-section increasing or decreasing in the direction of flow, that is a conical shape. In particular, a mixing element, preferably a so-called static mixer, can be arranged in the channel of the thrust piece.
The attachment of the spinneret holder to the distributor block can be carried out by conventional means such as screws or by other means. The joining known per se with the aid of a multistart thread has proved to be particularly advantageous. The thread is arranged on the outer periphery of the bottom part of the distributor block and, as a companion piece interacting therewith, on the inner periphery of the top part of the spinneret holder. It is possible here to achieve a sufficiently enduring attachment of the spinneret holder even with a rotation of the latter of only 180° or at the most 360°. It is important in this case to dimension the pitch of the thread to be so low that self-locking of this screw joint is achieved. Otherwise, another safeguard against unscrewing is to be provided, for example a retaining pin.
The shape and dimensions of the spin pack and its components are not subject to any restrictions--neither upwards nor downwards--and are matched to the particular requirements.
A further essential advantage in the spin pack according to the invention lies in the fact that its self-sealing action occurs reliably every time even after a repeated complete--intended or unintended--loss of pressure or pressure decrease.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in more detail below with reference to the drawings. In partly simplified representation:
FIG. 1 shows a particularly preferred embodiment of the spin pack in longitudinal profile;
FIG. 2 shows an embodiment of the thrust piece in longitudinal profile; and
FIGS. 3-7 show further embodiments of the spin pack in longitudinal profile.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In FIG. 1, the following parts are depicted, the arrangement, function and mode of action of which have already been described in detail: spinneret holder 1, which is attached with the aid of the two- three- or four-start thread 17 to the lower end of distributor block 8, arranged therein spinneret 2 having spinneret holes 18, distributor plate 11 designed as a perforated plate, angle seal 13 having axially upwards-pointing side 14 and radially inward-pointing side 15, filter pack 3, space 7 above filter pack 3, thrust piece 4 having central channel 12 and potlike shape 6 in the lower part of thrust piece 4 for receiving filter pack 3 and perforated plate 11, which projects above rim 20 of potlike shape 6, annular gap 16 between rim 20 and the shoulder of spinneret holder 1 at this point, which annular gap is covered and sealed by side 14 of angle seal 13, top 5 of thrust piece 4, which lies tightly against bottom 9 of distributor block 8, without leaving a gap, top seal 10 which covers and seals the joint between surfaces 5 and 9 and projects into channel 12 of thrust piece 4 and channel 19 of distributor block 8. The potlike shape 6 of the thrust piece 4 is engageable with the shoulder of the spinneret holder to limit movement of the thrust piece within the holder. The internal diameter of top seal 10 is equal to the diameter of channels 12 and 19, so that in this manner a smooth feed without projections is formed for the spinning liquid. Side 14 of seal 13 seals space 7 above filter pack 3 against the gap between thrust piece 4 and spinneret holder 1, in order to prevent penetration of spinning liquid into this gap. It exercises in this case, in an essentially simpler and reliable manner, the same function as did previously the expensive and fault-susceptible membrane seal of the prior art. Side 14 of seal 13 is--considered alone--of tubular design, side 15 has--considered alone--the shape of a flat seal (flat gasket). Side 14 seals in a radial direction under pressure (radial pressure component). As shown in FIG. 1, side 14 of seal 13 is disposed partially inside a bottom portion of potlike space 6 and partially inside spinneret holder 1. Also as illustrated in FIG. 1, angle seal 13 is preferably L-shaped. Instead of perforated plate 11, as depicted in FIG. 1,, spinneret 2 can alternatively be disposed at this point. At the inner surface of spinneret holder 1, a corresponding projecting support surface for supporting spinneret 2 is to be provided.
In an alternate embodiment, a mixing element 12' (shown in phantom in FIG. 1) is disposed in the channel 12 of the thrust piece 4. The mixing element 12' is preferably a static mixer.
FIG. 2 depicts an embodiment of thrust piece 4. The parts 5-7, 12 and 20, which have already been described above for FIG. 1, will not be enumerated and described again here. Reference numeral 21 depicts one of for example three holes, which facilitate fixing thrust piece 4 during the inserting of filter pack 3 and, possibly, distributor plate 11 by a corresponding number of pins arranged on a support. For this purpose, thrust piece 4 is arranged with surface 5 at the top. Channel 12 has in its top end section enlargement 22 to receive the bottom part of seal 10.
The embodiment depicted in FIG. 3 differs from the embodiment depicted in FIG. 1 only in that the middle, tubular seal 14 and the bottom, flat seal 15 are not parts of an angle seal. The bottom, flat seal 15 here is arranged beneath spinneret 2. Since all remaining parts are identical to those parts depicted in FIG. 1, continued description of this embodiment is dispensed with.
The embodiments depicted in FIGS. 4 to 7 differ essentially only in the design of thrust piece 4 and, when this is present, perforated plate 11 and in the design and arrangement of seals 14 and 15. All remaining parts are therefore only furnished with reference numbers if they are mentioned in the description below. In FIGS. 5 and 7 furthermore, the top parts and the filter pack are left out. Continued description of these figures below is superfluous with regard to the description of FIGS. 1 to 3.
FIG. 4 depicts an embodiment in which no distributor plate 11 is used, so that filter pack 3 lies directly on spinneret 2. Middle, tubular seal 14 and bottom, flat seal 15 here are again formed by the sides of an angle seal 13. In this embodiment, this is arranged beneath spinneret 2.
In the embodiment depicted in FIG. 5, middle, tubular seal 14 is arranged above distributor plate 11, and bottom, flat seal 15 is arranged between distributor plate 11 and spinneret 2. Distributor plate 11 here is not flat on the top, but designed in the shape of a pot--for example to receive filter granules such as sand or the like. Middle, tubular seal 14 projects into the potlike part of distributor plate 11 and of thrust piece 4 and lies against the inner surface of the "pot" rim. Annular gap 16 is clearly to be seen between the bottom rim of the potlike shape of thrust piece 4 and the top rim of the potlike shape of distributor plate 11, which annular gap is covered by middle, tubular seal 14, even if it should be enlarged by the movement of thrust piece 4 upwards, for example to double the width.
The embodiment depicted in FIG. 6 corresponds essentially to that depicted in FIG. 5, middle, tubular seal 14 being arranged here however in an annular groove arranged both at the bottom end of the potlike shape of thrust piece 4 and at the top end of the potlike shape of distributor plate 11.
The embodiment depicted in FIG. 7 corresponds essentially to that depicted in FIG. 5. However, in this embodiment, radially outward-leading annular gap 16 covered by middle, tubular seal 14 does not run horizontally as in the embodiments described above, but upwardly at an incline. It could equally well run downwards at an incline. The sealing action is not impaired as a result.
Although the invention has been described in detail, it will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the invention, which is defined in the following claims.
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A spin pack includes a spinneret holder, a spinneret, a filter pack and an axially movable thrust piece having a central channel and seals. The seals are used according to the invention being two tubular, radially sealing elements (seal or part of a seal).
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TECHNICAL FIELD
[0001] This invention is directed toward the use of error correcting code within memory systems, and, more particularly, one or more embodiments of this invention relates to decreasing the logic delay associated with calculating and comparing an error correcting code in command, address and data signals coupled between components in memory systems.
BACKGROUND OF THE INVENTION
[0002] In memory devices, such as dynamic random access memory (DRAM), as data channel frequencies increase, maintaining signal integrity becomes more important. Thus, error correcting codes (ECCs), such as cyclical redundancy check (CRC), have been proposed for use in high frequency memory devices to detect errors in signals transmitted between a memory controller and a memory device.
[0003] In a memory device, ECCs may be transmitted between a memory controller and the memory device along with command, address and data signals. The signals may be serialized into a packet and transferred along a channel. In a write command, once a packet is received by the memory device, an ECC value is calculated and compared with a known ECC value that was transmitted in the packet. If the values are the same, the command, address, and write data signals are validated and access is provided to a memory array in the memory device. Conversely, if the calculated ECC value is different from the known ECC value, then the command signal in the packet is suppressed and the write data is not sent to the memory array.
[0004] FIG. 1 shows a block diagram of a logic path 100 for calculating and comparing an ECC value in a high frequency memory device in accordance with the prior art. The logic path 100 for calculating the ECC value includes two static logic gates 102 and 106 that are clocked by respective flip flops 104 and 108 . More particularly, a packet is captured by a latch 122 responsive to an input capture clock. The command signals for the write command are sent to a command decoder 110 . In addition, the command signals, address signals and write data signals are sent to a set of first static logic gates (SL 1 ) 102 . For example, if 16 bits are captured, 4 command bits would be sent to the command decoder and all 16 bits would be sent to the SL 1 102 . The SL 1 102 completes a first part of the ECC calculation by generating a partial sum of the terms. The partial sum of the terms is output from the SL 1 102 , and latched into a first flip flop 104 . The partial sum is output from the first flip flop 104 and provided to a second set of static logic gates (SL 2 ) 106 . The remainder of the ECC calculation is completed in the SL 2 106 . Moreover, the calculated ECC is compared with the transmitted ECC in the SL 2 106 . When the calculated ECC value matches the transmitted ECC value, the SL 2 106 generates an ECC valid signal. From the SL 2 106 , the ECC valid signal is latched into a second flip flop 108 before being provided to an ECC valid logic gate 120 .
[0005] In parallel, a command decoder 110 decodes the command signals in the packet. The decoded command signals are clocked by a first and second flip flop 114 and 118 , respectively, so that the decoded command signal can be provided to the ECC valid logic gate 120 at the same time the ECC valid signal is provided to the ECC valid logic gate 120 . Thus, the decoded command signals are clocked out of the second flip flop 118 at about the same time as the ECC valid signal is clocked out of the second flip flop 108 . The ECC valid logic gate 120 validates the command and provides access to the memory array (not shown) when the calculated ECC value is the same as the transmitted ECC value. Conversely, the ECC valid logic gate 120 suppresses the command, when the calculated ECC value is different from the transmitted ECC value.
[0006] A timing diagram showing the delay for the logic path 100 of FIG. 1 is shown in FIG. 2 . In FIG. 2 , at time T 0 the signals on the packet that are applied to input terminals become valid. At time T 1 and in response to a rising edge of the clock signal, the signals are captured and provided to the SL 1 102 ( FIG. 1 ). The partial sum of terms is output from the SL 1 102 at time T 2 , which is some time period greater than a half period of the clock signal shown at the top of FIG. 2 . At time T 3 and in response to a rising edge of the clock signal, the partial sum of terms is clocked into the first flip flop 104 and provided to the SL 2 106 . The ECC valid signal is output from SL 2 106 at time T 4 and provided to the second flip flop 108 , which, again, requires a time period greater than a half period of the clock signal for the SL 2 106 to output the ECC valid signal. At time T 5 and in response to a rising edge of the clock signal, the ECC valid signal is clocked into the second flip flop 108 , and the decoded command signal is clocked out of the second flip flop 118 . At time T 6 the decoded command signal and ECC valid signal are provided to the ECC valid logic gate 120 . The ECC valid logic gate 120 generates an array command signal at time T 7 . The array command signal provides access to the memory array.
[0007] It can be seen from FIG. 2 that it requires two clock periods (i.e., T 1 -T 5 ) after the packet is applied to the memory device to validate the command signals in the packet. The signals from the SL 1 102 cannot be clocked into the first flip flop 104 by the falling edge of the clock signal after T 1 because the SL 1 102 requires more than one half period to complete its calculation. For the same reason, the signals from the SL 2 106 cannot be clocked into the second flip flop 108 by the falling edge of the clock signal following T 3 . Yet considerable time is wasted after the SL 1 102 and SL 2 106 complete their calculations, and the signals from the SL 1 102 and the SL 2 106 are clocked into the flip flops 104 and 108 , respectively, at time T 3 and T 5 , respectively.
[0008] For high frequency clock speeds, the prior art method shown in FIG. 1 for calculating ECC calculations has delay characteristics greater than one internal memory device clock cycle. When the ECC delay exceeds one clock period, a second clock period delay must be added to the delay to align the ECC calculation with the command signals to validate the command before accessing the memory array. Therefore, when the ECC logic delay is greater than one clock cycle but much less than two clock cycles, an entire second clock period delay is added.
[0009] One solution in the prior art for minimizing the delay associated with calculating and comparing the ECCs values has been to slow down the frequency of the internal memory clock cycle. By slowing down the clock frequency, the calculation and comparison of the ECC can be done in less time. In particular, the SL 1 102 can complete its calculation by the falling edge following the rising edge that clocks the signals into the latch 122 . Similarly, the SL 2 106 can complete its calculation by the falling edge following the rising edge that clocks the signals into the first flip flop 104 . As a result, the calculation and comparison can be done in one clock cycle, rather than having to extend it into two clock cycles. This is not a desirable solution, however, as it reduces the bandwidth of the memory device.
[0010] Therefore, there is a need for decreasing the logic delay associated with calculating and comparing ECCs without reducing the clock frequency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a block diagram of a logic path for calculating an error code in accordance with prior art.
[0012] FIG. 2 is a timing diagram representative of the time to calculate error code value in accordance with prior art.
[0013] FIG. 3 is a block diagram of a logic path for calculating an error code according to one embodiment of the invention.
[0014] FIG. 4 is a more detailed block diagram of the logic path of FIG. 3 according to one embodiment of the invention.
[0015] FIG. 5 is a timing diagram representative of the time to calculate error code value in accordance with one embodiment of the invention.
[0016] FIG. 6 is a block diagram of the logic path for calculating an error code according to one embodiment of the invention.
[0017] FIG. 7 is a timing diagram representative of the time to calculate error code value in accordance with one embodiment of the invention.
[0018] FIG. 8 is a block diagram of a memory device using a logic path for calculating an error code according to one embodiment of the invention.
[0019] FIG. 9 is a block diagram of an embodiment of a processor based system using the memory device of FIG. 8 .
DETAILED DESCRIPTION
[0020] Embodiments of the present invention are directed toward, for example, providing a method of reducing the logic delay associated with calculating ECCs. Certain details are set forth below to provide a sufficient understanding of the embodiments of the invention. However, it will be clear to one skilled in the art that various embodiments of the invention may be practiced without these particular details.
[0021] FIG. 3 shows a block diagram of a logic path 130 for calculating an error code according to one embodiment of the invention. In a write command, the logic path 130 captures a packet and distributes the incoming signals to a command decoder 110 and a set of static logic gates 132 in the same manner in FIG. 3 as in FIG. 1 . Therefore, in the interest of brevity, an explanation of the process will not be repeated. The set of static logic gates 132 are similar to the first set of static logic gates 102 in FIG. 1 in that the set of logic gates 132 calculates a partial sum of terms. The logic path 130 of FIG. 3 differs from the logic path 100 of FIG. 1 by completing the ECC calculation and comparing the calculated ECC value with the transmitted ECC value in a set of dynamic logic gates 134 . As in the prior art of FIG. 1 , if the calculated ECC value is valid, a valid signal is sent from the dynamic logic gates 134 to the ECC valid logic gate 120 . The ECC valid logic gate 120 validates the command before providing it to the memory array (not shown). As previously stated, the ECC valid logic 120 suppresses the decoded command if the calculated ECC value does not match the transmitted ECC value or generates an array command and thus, provides access to the memory array if the calculated ECC value does match the transmitted ECC value.
[0022] FIG. 4 is a detailed block diagram of the logic path 130 in FIG. 3 . A first input 121 receives the command, address, and data bits from a packet transmitted across a channel. The command, address, and data bits are clocked by latch 122 and provided to the set static logic exclusive-OR (XOR) gates 132 , which calculates a partial sum of the terms of the calculated ECC. The partial sum of the terms is then provided to the dynamic logic 134 . In particular, the partial sum of the terms is first provided to a set of static to dynamic circuits (S2Ds) 136 a . In addition, S2D 136 b is provided to align an output CLKD to the outputs from the S2D 136 a . The S2Ds 136 a convert the partial sum of the terms into monotonically rising output signals, which allows functional completeness for downstream logic. Monotonic signals travel in one direction during each evaluation cycle, for example from low to high. The output signals Q and Qb are complementary so that one of them may transition high each clock cycle. When the Q signal is high, the first set of dynamic XOR gates 138 and a second set of dynamic XOR gates 140 are enabled. When the dynamic XOR gates 138 and 140 are enabled, the remaining ECC calculation and comparison is completed without regard to a clock cycle. More particularly, the logic in the two sets of dynamic XOR gates 138 and 140 is completed as the signals are received in the respective gates, rather than relative to a clock cycle. Therefore, the time it takes to calculate the remaining part of the ECC value and compare the calculated ECC value with the transmitted ECC value is determined by the dynamic logic delay rather than by clock period. This dynamic logic delay is less than a clock cycle and thus is completed faster than the delay associated with the prior art.
[0023] In parallel with the above, input 123 receives the transmitted ECC value from the packet and is clocked by flip flop 142 . The transmitted ECC value is provided to an S2D circuit 146 . The transmitted ECC value is further provided to the second set of dynamic XOR gates 140 . As stated above, the calculated ECC value in the first set of dynamic XOR gates 138 is provided to the second set of dynamic XOR gates 140 . In the second set of dynamic XOR gates 140 , the calculated ECC value is compared with the transmitted ECC value. If the calculated ECC value matches the transmitted ECC value, an ECC valid command is provided to ECC valid logic 120 . There is no delay associated with aligning the decoded command signals with the ECC valid signal as they are provided to the ECC valid logic 120 . Rather, the decoded command signals may be provided to the ECC valid logic 120 at a different time than the ECC valid signal.
[0024] The logic path of FIGS. 3 and 4 calculates and compares the ECC value in less time than it takes in the prior art logic path shown in FIG. 1 . A timing diagram in accordance with the logic path in FIG. 4 is shown in FIG. 5 . The timing events T 0 -T 2 in the timing diagram of FIG. 5 represents the same timing events T 0 -T 2 of FIG. 2 , and therefore, will not be repeated in the interest of brevity. At time T 3 , however, the terms of the partial sum are clocked into the set of dynamic logic gates 134 and provided to a plurality of S2D circuits 136 a . As stated above, the dynamic logic gates 134 calculate the remaining part of the ECC value and compare the calculated ECC value with the transmitted ECC value. At time T 4 the decoded command signal is provided to the ECC valid logic 120 . At time T 5 and in response to a rising edge of S2D 136 b clkD, the monotonic signals are clocked out of the S2Ds 136 a . At time T 6 and when the calculated ECC value matches the transmitted ECC value, an ECC valid signal is provided to ECC valid logic 120 . The ECC valid signal may be provided to ECC valid logic 120 at a different time than the decoded command signal is provided to ECC valid logic 120 . Finally, at time T 7 ECC valid logic 120 generates and provides an array command signal to the memory array. The array command signal is generated and provided to the memory array in less time than it takes in the prior art timing diagram of FIG. 2 .
[0025] Although FIGS. 3 and 4 show a write command, the logic path 130 is also applicable to a read command issued by a memory controller. In a read command, the logic path 130 would verify the read command and read address on the memory device before providing access to the memory array. Furthermore, the logic path 130 is also applicable to a read packet received by a memory controller from a memory device. Once the read packet was received by the memory controller, the logic path 130 on the memory controller verifies the read data transmitted from the memory device to the memory controller.
[0026] In another embodiment of the invention, an alternative logic path may be used. FIG. 6 shows the logic path of FIG. 1 , but further includes a delay circuit between the first and second clock cycle of the internal memory clock. More particularly, the logic path 160 includes two static logic gates that are clocked by respective flip flops 104 and 108 . The first flip flop 104 is clocked by a first internal clock, similar to the internal clock of FIG. 1 . The second flip flop 108 is clocked by a delayed internal clock. The delay circuit 124 used to delay the internal clock may be any type of delay circuit. The minimum amount of delay that may be applied to the delay circuit 124 is likely greater than the time it takes the ECC valid signal to be output the second set of static logic gates 106 . Conversely, the maximum amount of delay that may be applied to the delay circuit 124 is likely less than the time marker for when the ECC valid signal is clocked into valid logic. Therefore, the amount of delay will not be longer than one clock period; however, the delay may be close to one clock period.
[0027] A timing diagram for the logic path of FIG. 6 in accordance with one embodiment is shown in FIG. 7 . FIG. 7 shows two clock signals, clock signal A and delayed clock signal B, where delayed clock signal B lags clock signal A by about 70%. Although FIG. 7 shows a delay of 70%, other delay amounts may be used. Clock signal A represents a clock signal similar to the clock signal in FIG. 2 . Furthermore time markers T 0 -T 4 are in response to clock signal A and represent the same timing events as in FIG. 2 . Therefore, time markers T 0 -T 4 will not be repeated for the sake of brevity. Time marker T 5 , however, is in response to clock signal B. In particular, at time T 5 and in response to the rising edge of clock signal B, the ECC valid signal is clocked out of the second flip flop 108 . At time T 6 a decoded command signal and ECC valid signal are provided to ECC valid logic 120 . The ECC valid logic 120 generates array command signal, which provides access to the memory array. Therefore, the time it takes to calculate and compare the ECC value is much less with the delay circuit 124 than without a delay circuit.
[0028] FIG. 8 shows a memory device 700 according to one embodiment of the invention. The memory device 700 is a dynamic random access (“DRAM”), although the principles described herein are applicable to DRAM cells, Flash or some other memory device that receives memory commands. The memory device 700 includes a command decoder 720 that generates sets of control signals corresponding to respective commands to perform operations in memory device 700 , such as writing data to or reading data from the memory device. The memory device 700 further includes an address circuit 730 that selects the corresponding row and column in the array. Both the command signals and address signals are typically provided by an external circuit such as a memory controller (not shown). The memory device 700 further includes an array 710 of memory cells arranged in rows and columns. The array 710 may be accessed on a row-by-row, page-by-page or bank-by-bank basis as will be appreciated by one skilled in the art. The command decoder 720 provides the decoded commands to the array 710 , and the address circuit 730 provides the row and column address to the array 710 . Data is provided to and from the memory device 700 via a data path. The data path is a bidirectional data bus. During a write operation write data are transferred from a data bus terminal DQ to the array 710 and during a read operation read data are transferred from the array to the data bus terminal DQ.
[0029] FIG. 9 is a block diagram of an embodiment of a processor-based system 600 including processor circuitry 602 , which includes the memory device 500 of FIG. 6 or a memory device according to some other embodiment of the invention. Conventionally, the processor circuitry 602 is coupled through address, data, and control buses to the memory device 500 to provide for writing data to and reading data from the memory device 500 . The processor circuitry 602 includes circuitry for performing various processing functions, such as executing specific software to perform specific calculations or tasks. In addition, the processor-based system 600 includes one or more input devices 604 , such as a keyboard or a mouse, coupled to the processor circuitry 602 to allow an operator to interface with the processor-based system 600 . Typically, the processor-based system 600 also includes one or more output devices 606 coupled to the processor circuitry 602 , such as output devices typically including a printer and a video terminal. One or more data storage devices 608 are also typically coupled to the processor circuitry 602 to store data or retrieve data from external storage media (not shown). Examples of typical storage devices 608 include hard and floppy disks, tape cassettes, compact disk read-only (“CD-ROMs”) and compact disk read-write (“CD-RW”) memories, and digital video disks (“DVDs”).
[0030] Although the present invention has been described with reference to the disclosed embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Such modifications are well within the skill of those ordinarily skilled in the art. Accordingly, the invention is not limited except as by the appended claims.
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Error correcting codes (ECCs) have been proposed to be used in high frequency memory devices to detect errors in signals transmitted between a memory controller and a memory device. For high frequency memory devices, ECCs have delay characteristics of greater than one clock cycle. When the delay exceeds one clock cycle but is much less than two clock cycles, an entire second clock cycle must be added. By calculating and comparing the ECC value in a static logic circuit and a dynamic logic circuit, the logic delay is substantially reduced. In addition, the ECC value may be calculated and compared using two sets of static logic gates, where the second static logic gate is clocked by a clock signal that is delayed relative to the clock signal of the first set of logic gates.
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This is a continuation of application Ser. No. 08/302,567, filed Sep. 8, 1994.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transmission system comprising a modem connected to a far-end modem by a transmission line, at least one of the modems comprising a line break detection device with a correlation meter for measuring a quantity representing the correlation between transmitted and received data and a threshold meter for triggering a line break alarm when this quantity exceeds a threshold value L.
2. Description of the Related Art
This type of device is known and on this subject Japanese Patent Application 4-150525, filed 12 Oct. 1990 can be consulted. This type of device is to cooperate with modems which comprise at least an echo canceller. This type of device has for its object to solve the problem of a break of the line connecting a near-end modem with a far-end modem. In the case of line break, echo cancellers, although they find themselves suddenly no longer adapted, can attune very rapidly to this new situation and this calls forth a risk of an alarm not being raised for a rather long period of time, for example, for several minutes. This period of time lost is detrimental to the user who pays for the occupation of a line which in fact no longer transmits information signals. Furthermore, if urgent problems are linked with this line, there is also time lost for finding another transmission line.
In the prior-art device the dedicated echo cancellers are used to the full, which implies much computation.
SUMMARY OF THE INVENTION
The invention provides a device of the type defined above which produces an alarm signal in a shorter period of time of the order of 10 seconds after a line break, without the need for much computation.
Therefore, such a device is characterized in that the correlation relates to a limited sample range which corresponds to the time of an echo signal.
BRIEF DESCRIPTION OF THE DRAWINGS
The following description accompanied by the appended drawings, all given by way of non-limiting example, will provide a more complete understanding of the invention. In the drawings:
FIG. 1 shows the structure of a modem comprising a line break detection device according to the invention, and
FIG. 2 is a block diagram relating to explanation of the operation of the detection device according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The modem 1 shown in FIG. 1 interconnects a digital terminal 5 and a telephone-type transmission line 7.
This modem is formed based upon processor units 10 and 11. The processor unit 10 is assigned to managing the modem and processor unit 11 comprises, as is customary, a microprocessor 12, a random-access memory 13 and a read-only memory 14 containing the program instructions which implement the invention. A first interface circuit 15 connects the modem 1 and user terminal 5. A second interface circuit 20 transforms the signals coming from the telephone line 7 into digital signals and also performs the reverse operation. Such a circuit is described in European Patent Specification EP 0 318 105.
The processor unit 11 performs various functions, and in particular that of an echo canceller. This function is shown in the form of operational blocks in FIG. 2.
In FIG. 2 the terminal 45 denotes the access of the data A(n) which are intended to be transmitted and 46 the access at which the data are received. A transversal filter 50 multiplies various samples of the time-shifted transmitted data A(n) by gradually changing constants. This filter 50 has for its object to simulate a near-end echo, so that a subtracter element 52 can remove signal distortion caused by the near-end echo by substracting the contribution of filter 50. In this manner a useful signal S(n) is obtained.
Another transversal filter 54 multiplies various samples of the time-shifted transmitted data A(n) by gradually changing constants. This filter 54 has for its object to simulate a far-end echo. As the far-end echoes undergo a certain frequency shift, a phase shifter corrects this shift. This phase shifter is shown in FIG. 2 in the form of a multiplier 56 which multiplies the output signals of filter 54 by e j θ. An element 55 producing a net delay makes it possible to have the filter 54 work under correct conditions. Thus a replica of a far-end echo is constituted, and a subtracter element 58 makes it possible to remove the signal distortion caused by this far-end echo.
Furthermore, an automatic gain control amplifier 60 makes it possible, by means of a control element 62, to maintain the level of the received data constant.
When there is a line break, the algorithms which give the phase shift values θ and the coefficients of the filters 50 and 54, are robust and adapt themselves to these new conditions. Consequently, an alarm is not raised until after too long a period of time.
To avoid this alarm delay, the invention provides a line break detection device formed by a correlation detector 80 for measuring the correlation between the transmitted data A(n) and the received data S(n) and by a threshold circuit 81. The invention is based on the following considerations. For simplification of the explanation, first the near-end echo will be discussed.
The various samples which will be discussed are complex and oversampled relative to the baud period T, so that a sample called X(n) is to be understood as having R symbols of which each symbol X r (n) is given by: ##EQU1##
To detect the line break, the correlation between the transmitted symbols A(n) and the received symbols S(n) is examined. Therefore, the following correlation measure is evaluated: ##EQU2## where S r (n+i) is the conjugate value of S r (n+i) and where E . . .! is the mathematical trend level of the value in brackets.
If the data of a remote modem are received, the values S(n) are different from those transmitted and the correlation measure I is small. If, on the other hand, there is a line break, the signal S(n) becomes a replica of the signal A(n), thus the correlation becomes strong.
To determine this value without the need for too much computation, Applicants make use of intercorrelation factors of the type:
ξ.sub.τ =E A(n)·S(n+τ)! (2)
and have found that the correlation measure I could be evaluated by utilizing the following formula: ##EQU3## In the equation (3), N1 and N2=N1+K-1 represent 6 and 8 ms, respectively. The calculation of the correlation is relevant because it is spread over the most significant 2 ms of the echo path delay time τ.
The values ξ i r (n) in which "r" represents the oversampling, are calculated with each sampling via the formula: ##EQU4## where λ<1 is a constant.
Thereafter a calculation of the modulus and a single summation are performed to obtain an estimate of I:
I←I+|ξ.sub.i |.sup.2
This quantity I is compared with a threshold value L. This value is independent of the echo path, i.e. of the component H(i) of its impulse response. This is due to the fact that the automatic gain control works so that the level of the received data is constant:
E |S(n)|.sup.2 !=L.sub.cag
There may be written that: ##EQU5## where:
σ.sup.2 =E |A(n)|.sup.2 !
Thus: ##EQU6## One has: ##EQU7## In the case of a line break one finally has:
I=σ.sup.2 L.sub.CAG R
It is sufficient to pose: ##EQU8## Therefore, the computation procedure can be simplified.
It will be recollected that the impulse response of the echo path stretches out over 15 ms. The greater part of the energy is found in the time interval 6 ms-8 ms!. This is to say that for a 2400 Hz symbol frequency the coefficients H r (M) have a high modulus for:
M.di-elect cons. N1;N2!N1=14N2=19
The simplification proposed by the invention thus consists of computing only a single term ξ i r for each sample (or R terms for each symbol). The calculation of the quantity I thus stretches out over:
K=(N2-N1+1) symbols.
The calculation procedure of I stored in memory 14 in the form of instructions will be the following: ##EQU9##
At the instants Kn+K-1, I is compared with a threshold L. If I>L, an alarm is raised signalling a line break.
As a variant, if one only has the real portion of the received signal S, the correlation factor ξR i r can be used based on the equation:
E A(n)Re S.sup.r (n)!!=E A(n)Re Σ.sub.j A(j)H.sup.r (n+M+j)!!=(σ.sup.2 /2)·H.sup.r (M)
where Re(. . . ) is the real part of the quantity in brackets. In practice it can be calculated as follows:
ξR.sub.i.sup.r (n)=(1-λ)ξR.sub.i.sup.r (n-1)+λA(n)Reλ S.sup.r (n+i)!
If the line break occurs on the side of the far-end modem, the mismatch relates only to the far-end echo. To monitor this phenomenon it is sufficient to select the terminals N1 and N2 discerningly as a function of the noise delay of the far-end echo. Correlation operations are effected simultaneously or alternately for the two types of echo.
In what has been stated above the transmit and receive clocks have been assumed to be synchronous. The possible slip of these two clocks relative to each other has no influence on the performance of the algorithm.
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A modem for transmission and reception of data samples over a transmission line includes a transmission line break detection device having a correlation meter for providing a measure of the degree of correlation between transmitted and received data samples. Such device further includes a threshold meter for triggering a line break alarm when the correlation exceeds a threshold value. The correlation relates to a limited number of data samples occurring during a portion of an echo period for reception of an echo of transmitted data samples.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is filed under the provisions of 35 U.S.C. §371 and claims the priority of International Patent Application No. PCT/US2009/036900 filed on Mar. 12, 2009, which in turn claims priority of Israeli Patent Application No. IL 190, 181 filed on Mar. 16, 2008, the contents of which are incorporated by reference herein for all purposes.
TECHNICAL FIELD OF THE INVENTION
The present invention relates to enhancement and optimisation in cleaning, sanitising and sterilising preparations. More particularly the present invention relates to preparations formulated for the disinfection and sterilisation of materials, commodities and surfaces contaminated with one or more species of micro-organisms including bacteria (and mycobacteria), fungi, algae and yeasts and their associated spores. The invention provides preparations whereby it is not only a sterilising preparation for killing and rendering spores lifeless but it also affects the necromass so formed that it becomes easily removable by water rinsing hence reducing the likelihood of biofilm formation.
Therefore the present invention gives a solution for the requirement of effective preparations that can be used for the cleaning, sanitisation and sterilisation in general and more particularly cleaning, sanitisation and sterilisation of surfaces and equipment in the human and animal healthcare sector as part of an holistic infection control strategy.
BACKGROUND OF THE INVENTION
There are known cleaning techniques that involve high temperatures that may be detrimental to the particular equipment or that involve powerful chemical reagents such as oxidants like peracetic acid that also adversely affect not only the primary medical devices but also the equipment used to clean the devices.
It is well known that transient supramolecular organisation of amphoteric molecules form micelles. The transitional quality of such organized groups is believed to provide an explanation of the enhanced activity of microbiocides when combined in certain cleaning preparations as reported in literature.
There is a known detergent action, namely the gathering together of surfactant molecules to form micelles. Such micelles are also alluded to in known theories explaining the observed biological action of cationic biocides such as quaternary ammonium compounds. Molecules of this type interact fleetingly with the phospholipids and peptidoglycan parts of cytoplasmic membranes of micro-organisms, which interaction causes these membranes to become disturbed and then to explode, leading to the death of the cell.
Up to the present time, an overabundance of inventions for preparations for disinfecting and sterilising materials and surfaces contaminated with bacteria and bacterial spores have come about through empirical observations of biological action.
All of these inventions require some form of microbiocidal fluid which is brought into contact with the contaminated material or surface long enough to be able to disinfect and sterilise said contaminated material or surface.
Prior Art provides several cleaning preparations as follows:
Baugh et al. U.S. Pat. No. 6,656,919 describes a microbiocidal solution which can range from a simple solution of a single component such as aqueous formaldehyde to complex mixtures of microbiocides and various adjuncts including microbiologically active components such as germination promoters or other inert material that displays surfactant properties. The microbiocidal properties of cationic surfactants such as quaternary ammonium compounds (QAC) and biguanidinium salts are well known and authenticated.
Spooner et al WO9820738 describes microbiological activity which was found to be enhanced when bis(biguanide) microbiocides were combined with polymeric biguanides in contact lens cleaning solutions.
Van Buskirk et al U.S. Pat. No. 5,856,290 describes the combination of QAC and N-alkylpropylenediamine microbiocides with a mixture of non-ionic surfactants which was observed to lead to a noticeable improvement in microbiocidal efficacy.
Lehman et al U.S. Pat. No. 4,920,100 describes bactericidal alcohols and carboxylic acids which were also observed to demonstrate potentiated effects when mixed with certain non-ionic surfactants.
Biermann et al U.S. Pat. No. 4,748,158 describes potentiation in dental cleaning applications of mixtures of chlorhexidine salts and alkylpolyglucosides.
Toshuki et al JP57009717 describes synergistic germicidal activity in mixtures of chlorhexidine salts or polyhexamethylenebiguanide and polyoxyethylene alkyl ethers in the proportions 1:1:W3 which has been reported.
EP05252443.6 suggests the formation of a transient intermediate to explain the observed improvement in minimum inhibitory concentration data for chlorhexidine salts when mixed with various non-ionic surfactants, and until that time a mechanism explaining the origin of such improved microbiocidal efficacy had not been defined.
U.S. Pat. No. 6,303,557 uses biocides and surfactants which differ from those of the present invention, does not include the aliphatic alcohol and requires the presence of sequesterants and amphoteric surfactants to achieve its enhanced microbiocidal activity.
Moreover, there are known U.S. Pat. Nos. 6,814,088, 7,082,951 and 7,094,741 which are for aqueous compositions for treating a surface. However said patents are for preparations which afford superior filming/streaking and shine retention whilst providing disinfecting/antimicrobial benefits. The preparations/compositions of said patents are different from that of the present invention inter alia in that they exclude the component QAC (Quaternary Ammonium Compound), being a cationic microbiocide, which is an essential component of the present invention.
Another known U.S. Patent is U.S. Pat. No. 7,166,563. Said patent is different from the present application as it differs in that QAC are absent from the mixture which may contain PHMB and APG together with other components not used in the present invention.
As noted from the above, none of the above Prior Art gives a solution for the most efficient cleaning, sanitising and sterilising preparations.
It has been observed in some formulations that the activity of particular microbiocides is compromised and considerably diminished by the presence of certain surfactants. It is the recognition of such behaviour by means of empirical observation and the subsequent development of an explanatory theorem which has brought about the formulation of the present invention.
SUMMARY OF INVENTION
According to the present invention, cleaning, sanitising and sterilising preparations (hereinafter “cleaning preparation”) may be prepared using known microbiocides provided that they are mixed in such a way that chemical species that interfere with said preparation are avoided and/or destroyed. The present invention thus consists in a cleaning preparation comprising a mixture of cationic microbiocides and non-ionic surfactants in an aqueous matrix.
DETAILED DESCRIPTION OF THE INVENTION
The present invention consists in a cleaning preparation comprising a mixture of cationic microbiocides and non-ionic surfactants in a ratio of between 8:1 to 2:1 in an aqueous matrix.
For clarity's sake it should be noted that when referring to cleaning, sanitisation and sterilisation preparations it refers to cleaning, sanitisation and sterilisation preparations per se or to any other preparations from said group such as disinfecting preparations, preparations for use in hygiene (disinfecting), preparations for use in hygiene (sterilising), disinfectants, anti-bacterial preparations, anti-bacterial preparations for medical use, detergents for medical use, detergents for medical use having anti-bacterial properties, disinfectants for hygiene purposes, disinfectants for medical and veterinary use, disinfectants for hygiene purposes or for medical and veterinary use having anti-bacterial properties, Bactericidal preparations, Virucdidal preparations, Fungicidal preparations, Tuberculocidal preparations, Sproicidal preparations, Biocides, anti-microbial preparations, chemicals having antimicrobial properties (medical or veterinary), cleaning and sanitising solutions and preparations for medical use, rinse and drying aids for use in medical washing applications, chemicals for use in cleansing, disinfecting and/or decontamination applications in the medical field, medical scrubs (sterilising or disinfecting, scrubs (preparations) for medical use, surface hygiene products, medicated anti-bacterial washes, anti-bacterial cleansers
In one embodiment of the present invention, the cleaning preparation comprises a mixture of cationic microbiocides and non-ionic surfactants in a ratio of between 7:1 to 2:1 and more preferably 2.3 to 1 in an aqueous matrix.
In another embodiment of the present invention, the cleaning preparation comprises a mixture of cationic microbiocides and non-ionic surfactants in a ratio of between 8:1 to 4:1.
In a further embodiment of the present invention, the mixture of cationic microbiocides and non-ionic surfactants forms transient supramolecular assemblies which enhance the microbiocidal efficiency.
According to the present invention, cleaning, sanitising and sterilising solutions can be prepared using known microbiocides provided that they are mixed in such a way that transient supramolecular assemblies can be formed and that chemical species which interfere with this molecular organisation can be avoided.
The cationic microbiocides of the present invention may be selected from among (a) guanidine salts and (b) positive non-metallic salts, preferably quaternary ammonium salts.
The guanidine salts of the present invention may be guanidine salts per se, biguanidinium salts, guanide salts, biguanidine salts or biguanide salts, and all the above are standing for the same molecules.
The guanidine salts of the present invention may be selected from among the following salts, however they are not restricted thereto: chlorhexidine digluconate, dihydrochloride and diacetate; hexamethylenebis(ethylhexyl)biguanide dihydrochloride; oxocyclohexadienylideneaminoguanidine thiosemicarbazone; bis(chlorophenylamidino)piperazinedicarboxamidine dihydrochloride and polyhexamethylenebiguanidine hydrochloride.
The positive non-metallic salts may be selected from among quaternary ammonium salts, phosphonium salts and sulfonium salts.
The quaternary ammonium salts of the present invention may be selected from among the following salts, however they are not restricted thereto: quaternary salts containing either or both aliphatic or aromatic moieties; aliphatic groups including alkoxy groups which may contain from one to 30 carbon atoms in linear or branched arrangements; alicyclic groups which may be cyclohexyl and its alkylated and alkoxylated derivatives. The preferred quaternary ammonium salt of the present invention is didecyldimethylammonium chloride.
The counter ions of the guanidine and quaternary ammonium salts may be selected from among halides, preferably chloride; bicarbonate, borate, carbonate, fluoborate, fluoride, phosphate, and sulphate.
In a preferred embodiment of the present invention, the cationic microbiocides of the present invention consist of a mixture of polymeric biguanidinnium chloride or polyhexamethylenebiguanidine hydrochloride and didecyldimethylammonium chloride in the ratio of between 1:1 and 1:1.25.
The non-ionic surfactants, i.e. the water soluble non-ionic surfactants of the present invention, are widely available and include primary and secondary alcohol ethoxylates and condensates with oligoglycosides; e.g. alkanol containing about 8 to 18 carbon atoms in either straight chain or branched arrangements condensed with six to ten moles of ethylene oxide or four to six moles of monosaccharide such as glucose.
In a preferred embodiment of the present invention, the non-ionic surfactants comprise an alkylpolyglucoside and an alkylethoxylate, most preferably a C 9 -C 10 alkyltetraglucoside, a C 9 -C 11 alkylhexaethoxylate or C 9-11 Alcoholethoxylate.
In a further embodiment of the present invention the cleaning preparation of the present invention comprises one or more solubilising agents. Such solubilising agents may include lower aliphatic alcohols such as ethanol, propan-1-ol and propan-2-ol; organic acids such as acetic acid, propanoic acid, glycolic acid, lactic acid and citric acid; and common salts of Group 1 & 2 metals such as potassium and sodium cations with any of the following anions: halides such as chloride, fluoride, bromide, iodide; phosphate, carbonate, bicarbonate, citrate, lactate, phosphate and sulphate; and combinations thereof. However they are not restricted to said agents.
In a preferred embodiment of the present invention, the solubilising agents comprise propan-2-ol, citric acid and optionally sodium fluoride. In one embodiment of the present invention the preparation of the present invention comprises at least 5% propan-2-ol, more preferably 10% and most preferably 20%. Preferably the preparation of the present invention comprises no more than 0.3% citric acid. In a further preferred embodiment of the present invention, the present invention comprises up to 30% propan-2-ol and comprises 0.4% citric acid.
In yet a further embodiment of the present invention, the cleaning preparation of the present invention comprises one or more further cationic surfactant such as alkylbenzyldimethylammonium chloride, Alkyl(C 12-16 ) Dimethylbenzyl Ammonium Chloride and any other cationic surfactants, preferably with an aromatic moiety selected among but not restricted to benzylhexyldimethylammonium chloride, benzyloctyldimethylammonium chloride, benzyldecyldimethylammonium chloride, benzyldodecyldimethylammonium chloride, benzyltetradecyldimethylammonium chloride, benzyloctadecyldimethylammonium chloride, and similar species in which the benzyl moiety is replaced by tolyl- and xylyl- (ie methylbenzyl- and dimethylbenzyl-) moieties. In a further embodiment said cationic surfactant may be present at about one part per 8 parts of non-ionic surfactant mixture.
In yet a further embodiment said cationic surfactant may be present at about one part per 2.6 parts of non-ionic surfactant mixture. Said cationic surfactant may be used also as a clearing agent.
In a further option of the present invention the preparation comprises also fragrances, aromatics, coloring or any further materials. Such a material may be any commercial material such as: SAFA 30472 of Parfex S.A. in any desired amount such as 0.1 to 5%.
A preferred embodiment of the present invention comprises an aqueous preparation which may be diluted to form the required strength of the preparation comprising the following components: Propan-2-ol, Didecyldimethylammonium chloride, Polyhexamethylenebiguanidine HCld, Alkylpolyglucoside, Alkylbenzyldimethylammonium chloride, Alkylethoxylate, Citric acid and optionally Sodium fluoride.
In one embodiment of the present invention comprising the following components in an aqueous preparation in the following concentration shown in Table I (in order of decreasing abundance) expressed as weight percent:
TABLE I
Component
from
to
Propan-2-ol
0.16
30
Didecyldimethylammonium chloride
0.1
10
Polyhexamethylenebiguanidine HCld
0.08
9
Alkylpolyglucoside
0.04
4
Alkylbenzyldimethylammonium chloride
0.03
4
Alkylethoxylate
0.01
7
Citric acid
0.002
0.4
Sodium fluoride
0
0.1
In a further embodiment of the present invention comprising the following components in an aqueous preparation in the following concentration shown in Table II (in order of decreasing abundance) expressed as weight percent:
TABLE II
Component
from
to
Propan-2-ol
0.3
30
Didecyldimethylammonium chloride
0.1
10
Polyhexamethylenebiguanidine HCld
0.09
9
Alkylpolyglucoside
0.04
4
Alkylbenzyldimethylammonium chloride
0.04
4
Alkylethoxylate
0.07
7
Citric acid
0.004
0.4
Sodium fluoride
0
0.1
In a further embodiment of the present invention comprising the following components in an aqueous preparation in the following concentrations are shown in Table III (in order of decreasing abundance) expressed as weight percent:
TABLE III
Component
from
to
Propan-2-ol
0.16
16
Didecyldimethylammonium chloride
0.1
10
Polyhexamethylenebiguanidine HCld
0.08
8
Alkylpolyglucoside
0.04
4
Alkylbenzyldimethylammonium chloride
0.03
3
Alkylethoxylate
0.01
1
Citric acid
0.002
0.2
Sodium fluoride
0.001
0.1
In a further embodiment of the present invention, the preparation comprises an aqueous preparation in terms of weight per percent in the form of a concentrated solution having the following components: Propan-2-ol in the amount of 8.25; Didecyldimethylammonium chloride in the amount of 4.7; Polyhexamethylenebiguanidine HCld or polymeric biguanidinnium chloride in the amount of 4.33; Alkylpolyglucoside in the amount of 0.75; Alkylbenzyldimethylammonium chloride in the amount of 1.55; Alkylethoxylate in the amount of 3.25; Citric acid in the amount of 0.15 and Sodium fluoride in the amount of 0.001.
In another embodiment of the present invention, the preparation comprises an aqueous preparation in terms of weight per percent in the form of a super-concentrated solution having the following components: Propan-2-ol in the amount of 23; Didecyldimethylammonium chloride in the amount of 8.2; Polyhexamethylenebiguanidine HCld or polymeric biguanidinnium chloride in the amount of 7.1; Alkylpolyglucoside in the amount of 3.85; Alkylbenzyldimethylammonium chloride in the amount of 2.25; Alkylethoxylate in the amount of 1; and Citric acid in the amount of 0.4.
In a further embodiment of the present invention comprises a process for the manufacture of the cleaning preparation by combining the components at any ambient temperature.
In one embodiment of the present invention, the process for manufacture of the cleaning preparation comprises the following steps:
a. dissolve the salts in water (citric acid+sodium fluoride, if any) b. add the Alkylethoxylate and Alkylpolyglucoside c. add the Didecyldimethylammonium chloride and Alkylbenzyldimethylammonium chloride. d. add Propan-2-ol e. add Polyhexamethylenebiguanidine HCld
In one embodiment, the cleaning preparation is manufactured by combining the following components as shown in Table IV in the order given at ambient temperature. Quantities are in parts by weight.
TABLE IV
weight
Ingredient
by wt
soln conc
percent
Didecyldimethylammonium
100
as 50% solution
10
chloride
Alkylbenzyldimethylammonium
30
as 50% solution
3
Chloride
Alkylpolyglucoside
40
as 75% solution
4
Alkylethoxylate
10
neat
1
Citric acid
2
in 40 parts water
0.2
Sodium fluoride
1
in 40 parts water
0.1
Propan-2-ol
160
neat
16
Polyhexamethylenebiguanidine
80
as 20% solution
8
HCld
In another preferred embodiment, the cleaning preparation is manufactured a super-concentrated preparation by combining the following components as shown in Table V in the order given at ambient temperature. Each component is added successively and stirred gently to give a clear solution before the next component is added. Quantities are in parts by weight.
TABLE V
Ingredient
added
by wt
(active) soln conc
actual wt
Didecyldimethylammonium
94
as 50% solution
188
chloride
Alkylbenzyldimethylammonium
31
as 50% solution
62
Chloride
Alkylpolyglucoside
15
as 50% solution
30
Alkylethoxylate
65
neat
65
Citric acid
3
in 54 parts water
3
Propan-2-ol
165
neat
165
Polyhexamethylenebiguanidine
87
as 20% solution
433
HCld
Total wt.
1000
The present invention optimises the activity of quaternary ammonium and biguanidine microbiocides when combinations of non-ionic surfactants and modifiers in aqueous media are present. The present invention demonstrates excellent cleaning properties, including soil lift and suspension, as well as exceptional sporicidal activities.
In a further embodiment of the present invention, the cleaning preparation is manufactured as a super-concentrate which is diluted with water to form a concentrate for transportation to the site of use where it is diluted further with water to prepare the required solution, i.e. for cleaning and/or for rinsing and/or for sanitisation and/or for sterilisation by appropriate dilution.
The present invention thus provides various preparations of differing concentrations, e.g. as a super-concentrate, as a concentrate, as a diluted solution for the manufacture of fabric wipes, as another diluted solution for use as a spray, as a soaking solution of various strengths, as a final rinse aid solution etc.
In one embodiment of the present invention, the preparation comprises an aqueous preparation in terms of weight per percent in the form of wipes having the following components: Propan-2-ol in the amount of 1.65; Didecyldimethylammonium chloride in the amount of 0.94; Polyhexamethylenebiguanidine HCld or polymeric biguanidinnium chloride in the amount of 0.87; Alkylpolyglucoside in the amount of 0.15; Alkylbenzyldimethylammonium chloride in the amount of 0.31; Alkylethoxylate in the amount of 0.65; Citric acid in the amount of 0.03 and Sodium fluoride in the amount of between 0.0001.
In still a further embodiment of the present invention, the preparation comprises an aqueous preparation in terms of weight per percent in the form of a spray having the following components: Propan-2-ol in the amount of 0.66; Didecyldimethylammonium chloride in the amount of 0.38; Polyhexamethylenebiguanidine HCld or polymeric biguanidinnium chloride in the amount of 0.35; Alkylpolyglucoside in the amount of 0.06; Alkylbenzyldimethylammonium chloride in the amount of 0.13; Alkylethoxylate in the amount of 0.26; Citric acid in the amount of 0.012 and Sodium fluoride in the amount of between 0.00004.
In yet a further embodiment of the present invention the cleaning preparation of the present invention may be used for cleaning and/or for sanitising and/or for sterilising. More particularly the preparation of the present invention is used for the enhancement and optimisation in cleaning, sanitising and sterilising. The preparation in accordance with the present invention may be used for the disinfection and sterilisation of materials, commodities and surfaces contaminated with one or more species of micro-organisms including bacteria (and mycobacteria), fungi, algae and yeasts and their associated spores. The preparations may be used in sterilising preparation for killing and rendering spores lifeless and also may affect the necromass so formed in such a way that it becomes easily removable by water rinsing hence reducing the likelihood of biofilm formation.
Furthermore the present invention may be used for cleaning, sanitisation and sterilisation in general and more particularly for cleaning, sanitisation and sterilisation of surfaces as such and equipment used in the human and animal healthcare sector as part of an holistic infection control strategy.
The present invention will now be described in reference to the accompanying examples without being limited by same.
EXAMPLES
Example 1
Example 1 is comprised of a mixture of the biocides: chlorhexidine digluconate and didecyldimethylammonium chloride in the ratio by weight of 1:1 in an aqueous dispersion that included two non-ionic (alcohol ethoxylate and alkylpolyglucoside) surfactants in the proportions by weight of 2:3; the ratio by weight of biocide to non-ionic surfactant was 8:1. A small amount (0.2%) of an organic acid (citric acid) and an aliphatic alcohol (propan-2-ol, 8%) by weight to aid solubility were included.
Example 2
Example 2 is comprised of a mixture of the biocides: polyhexamethylenebiguanidine hydrochloride and didecyldimethylammonium chloride in the ratio by weight of 1:1 in an aqueous dispersion that included two non-ionic (alcohol ethoxylate and alkylpolyglucoside) surfactants in the proportions by weight of 2:3; the ratio by weight of biocide to surfactant was approximately 8:1. A small amount (0.2%) of citric acid was included.
Example 3
Example 3 is comprised of a mixture of the biocides: polyhexamethylenebiguanidine hydrochloride and didecyldimethylammonium chloride in the ratio by weight of 1:1 in an aqueous dispersion that included two non-ionic (alcohol ethoxylate and alkylpolyglucoside) surfactants and a cationic surfactant, e.g. alkylbenzyldimethylammonium chloride, in the proportions by weight of 10:14:3; the ratio by weight of biocide to surfactant was approximately 5.5:1. A small amount (0.2%) of an organic acid and an aliphatic alcohol (16%) by weight to aid solubility were included together with an alkali metal halide salt (0.1%) to modify the viscosity.
The above examples appeared as clear viscous solutions that were diluted with water in the proportions of 1 part example and either 9 or 24 parts of water to provide the solutions subjected to microbiocidal in particular sporicidal evaluation.
Example 4
Microbiological Activity Data
Data were collected following application of standard testing procedures (EN13704) carried out by independent testing laboratories and are shown in Table VI.
TABLE VI
Example
1(10%)
2 (10%)
3(4%)
Time/min
5
5
1
Log
5.0
>6.42
4.74
reduction
These and other data indicate a clear advantage to using a combination of non-ionic surfactants and cationic microbiocides to afford effective sporicidal cleaning preparations.
Example 5
Manufacture of Example 3
Super-concentrate solution is manufactured by combining the following components in the order given at ambient temperature, the results are shown in Table VII Each component is added successively and stirred gently to give a clear solution before the next component is added. Quantities are in parts by weight.
TABLE VII
actual
Ingredient
by wt
soln conc
vol added
Didecyldimethylammonium
100
as 50% solution
200
chloride
Alkylbenzyldimethylammonium
30
as 50% solution
60
Chloride
Alkylpolyglucoside
40
as 75% solution
50
Alkylethoxylate
10
neat
10
Citric acid
2
in 40 parts water
40
Sodium fluoride
1
in 40 parts water
40
Propan-2-ol
160
neat
200
Polyhexamethylenebiguanidine
80
as 20% solution
400
HCld
Total volume
1000
The sterilising solutions used for the purpose of cleaning, sanitising and sterilising are prepared by appropriate dilution of the above super-concentrate.
Example 6
The microbiocidal efficacy of the diluted aqueous solution for use as a spray based on Example 3 at 4% dilution has been investigated in a series of EN protocols involving contact times of 1 minute with the following spores and organisms and the results are given in Table VIII (the results are given in log reduction).
TABLE VIII
Bacillus subtilis spores
6.23
Clostridium difficile spores
>6.39
Pseudomonas aeruginosa
>6.71
Staphylococcus aureus
>6.50
Escherichia coli
>6.63
Enterococcus hirae
>6.42
Klebsiella pneumoniae
5.49
(6.12 with 5 min contact)
Enterococcus faecalis
>6.58
Proteus mirabilis
5.89
Streptococcus pyogenes
5.97
(>6.16 with 5 min contact)
Salmonella choleraesuis
>6.22
Listeria monocytogenes
>6.33
Methicillin resistant S. aureus
>6.55
Mycobacterium terrae
5.74
(>6.51 with 3 min contact)
HIV
>3.5*
Human Corona Virus
>3.5*
Human Influenza Virus
>4.0
Herpes Simplex Virus
3.17
Aspergillus niger
5.68
Candida albicans
5.83
Tricophyton - mentagrophytes
4.94
Example 7
Example 7 is comprised of a mixture of the biocides: polyhexamethylenebiguanidine hydrochloride and didecyldimethylammonium chloride in the ratio by weight of 1:1.1 in an aqueous dispersion that included two non-ionic (alcohol ethoxylate and alkylpolyglucoside) surfactants and a cationic surfactant, e.g. alkylbenzyldimethylammonium chloride, in the proportions by weight of 4.3:1:2.1; the ratio by weight of biocide to surfactant was approximately 1.63:1. A small amount (0.3%) of an organic acid (citric acid) and an aliphatic alcohol (16.5%) by weight to aid solubility were included.
Example 8
Example 8 is comprised of a mixture of the biocides: polyhexamethylenebiguanidine hydrochloride and didecyldimethylammonium chloride in the ratio by weight of 1:1.1 in an aqueous dispersion that included two non-ionic (alcohol ethoxylate and alkylpolyglucoside) surfactants and a cationic surfactant, e.g. alkylbenzyldimethylammonium chloride, in the proportions by weight of 4.3:1:2.1; the ratio by weight of biocide to surfactant was approximately 1.63:1. A small amount (0.3%) of an organic acid (citric acid) and an aliphatic alcohol (16.5%) by weight to aid solubility were included. Moreover 0.1% sodium fluoride was inserted.
Example 9
Microbiological Activity Data
Data were collected following application of standard testing procedures (EN13704) carried out by independent testing laboratories and are shown in Table IX by checking for the presence of Bacillus Subtilis .
TABLE IX
Example
7(4%)
Time/min
1
Log reduction
6.0
These and other data indicate a clear advantage to using a combination of surfactants and cationic microbiocides to afford effective sporicidal cleaning preparations.
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The present invention relates to a cleaning preparation, namely to a cleaning, disinfecting, sanitizing and sterilizing preparation. Said preparation comprises a mixture of cationic microbiocides and non-ionic surfactants.
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BACKGROUND OF THE INVENTION
[0001] Micro-Electro-Mechanical Systems (MEMS) inertial measurement units contain three gyroscopes and three accelerometers for detecting changes in attitude and acceleration. Typically, the three gyroscopes and the three accelerometers are mounted on separate orthogonal axis, each with their own set of control and read-out electronics. It is appreciated that there is an inherent cost in the assembly of the MEMS inertial measurement unit in view that the three gyroscopes and the three accelerometers must be precisely installed, in view that a relatively large amount of processing capacity is required to process information form six separate units, and in view of the power source requirements to power the three gyroscopes and the three accelerometers. Many applications require a reduction in size, computational requirements, power requirements, and cost of a MEMS inertial measurement unit. In view of these constraints, it would be advantageous to reduce the number of sensing devices in a MEMS inertial measurement unit.
[0002] A conventional MEMS gyroscope may be used to determine angular rotation by measuring Coriolis forces exerted on resonating proof masses. A conventional MEMS gyroscope includes two silicon proof masses mechanically coupled to and suspended from a substrate, typically glass, using one or more silicon flexures. A number of recesses etched into the substrate allow selective portions of the silicon structure to move back and forth freely within an interior portion of the device. In certain designs, substrates can be provided above and below the silicon structure to sandwich the proof masses between the two substrates. A pattern of metal traces formed on the substrate(s) can be used to deliver various electrical bias voltages and signal outputs to the device.
[0003] A drive system for many MEMS gyroscopes typically includes a number of drive elements that cause the proof mass to oscillate back and forth along a drive axis perpendicular to the direction in which Coriolis forces are sensed. In certain designs, for example, the drive elements may include a number of interdigitated vertical comb fingers configured to convert electrical energy into mechanical energy using electrostatic actuation. Such drive elements are described, for example, in U.S. Pat. No. 5,025,346 to Tang et al., entitled “LATERALLY DRIVEN RESONANT MICROSTRUCTURES,” and U.S. Pat. No. 7,036,373 to Johnson et al., entitled “MEMS GYROSCOPE WITH HORIZONTALLY ORIENTED DRIVE ELECTRODES,” both of which are incorporated herein by reference in their entirety.
[0004] Other types of MEMS devices may be used to measure both linear acceleration and rotation. However, such MEMS devices are operated in an open loop mode wherein the acceleration and rotation (gyro) responses are coupled with and depend on each other. Accordingly, systems that independently measure both linear acceleration and rotational movement require at least two different devices so that the acceleration sensing is decoupled from the rotation sensing, which may result in increased complexity and costs.
SUMMARY OF THE INVENTION
[0005] Systems and methods of determining linear acceleration and rotation using a Micro-Electro-Mechanical Systems (MEMS) inertial sensor are disclosed. An exemplary embodiment has a first proof mass; a second proof mass; a first electrode pair operable to apply a first linear acceleration rebalancing force to the first proof mass; a second electrode pair operable to apply a second linear acceleration rebalancing force to the second proof mass; a third electrode pair operable to apply a first Coriolis rebalancing force to the first proof mass; and a fourth electrode pair operable to apply a second Coriolis rebalancing force to the second proof mass.
[0006] In accordance with further aspects, an exemplary embodiment applies a first linear acceleration rebalancing force via a first electrode pair to a first proof mass, applies a second linear acceleration rebalancing force via a second electrode pair to a second proof mass, applies a first Coriolis rebalancing force via a third electrode pair to the first proof mass, applies a second Coriolis rebalancing force via a fourth electrode pair to the second proof mass, determines a linear acceleration corresponding to the applied first and second linear acceleration rebalancing forces, and determines a rotation corresponding to the applied first and second Coriolis rebalancing forces.
[0007] In accordance with further aspects, another exemplary embodiment senses a change in a first capacitance between a first electrode of a first electrode pair and a first proof mass, senses a change in a second capacitance between a second electrode of the first electrode pair and the first proof mass, senses a change in a third capacitance between a first electrode of a second electrode pair and a second proof mass, senses a change in a fourth capacitance between a second electrode of the second electrode pair and the second proof mass, senses a change in a fifth capacitance between a first electrode of a third electrode pair and the first proof mass, senses a change in a sixth capacitance between a second electrode of the third electrode pair and the first proof mass, senses a change in a seventh capacitance between a first electrode of a fourth electrode pair and the second proof mass, and senses a change in an eighth capacitance between a second electrode of the fourth electrode pair and the second proof mass. The embodiment is operable to determine a linear acceleration from the sensed first capacitance, the sensed second capacitance, the sensed third capacitance, and the sensed fourth capacitance. The embodiment is also operable to determine a rotation from the sensed fifth capacitance, the sensed sixth capacitance, the sensed seventh capacitance, and the sensed eighth capacitance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Preferred and alternative embodiments are described in detail below with reference to the following drawings:
[0009] FIG. 1 is a conceptual perspective view of electrodes and proof masses for a portion of an embodiment of the inertial sensor;
[0010] FIG. 2 is a conceptual perspective view of electrodes and proof masses for an alternative embodiment of the inertial sensor;
[0011] FIG. 3 is a conceptual side view of an embodiment of the inertial sensor;
[0012] FIG. 4 is a conceptual side view of an embodiment of the inertial sensor with applied initialization rebalancing forces;
[0013] FIG. 5 is a conceptual side view of an embodiment of the inertial sensor with an applied linear acceleration;
[0014] FIG. 6 is a conceptual side view of an embodiment of the inertial sensor with an applied rotation;
[0015] FIGS. 7-9 illustrate applied and sensing voltages for embodiments of the inertial sensor; and
[0016] FIG. 10 is a block diagram illustrating an exemplary implementation of a digital signal processing system coupled to an embodiment of the inertial sensor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Embodiments of the inertial sensor 100 decouple acceleration sensing and rotation sensing so that rotation and acceleration are independently determinable. FIG. 1 is a block diagram of a portion of an embodiment of an inertial sensor 100 . The exemplary portion of the inertial sensor 100 is operable to sense either linear acceleration or rotation. Other portions of the inertial sensor 100 that sense rotation are described and illustrated below.
[0018] The illustrated portion of the inertial sensor 100 comprises a first proof mass 102 (interchangeably referred to herein as the left proof mass 102 ) and a second proof mass 104 (interchangeably referred to herein as the right proof mass 104 ). The left proof mass 102 is between an upper sense electrode 106 (interchangeably referred to herein as the upper left sense (ULS) electrode 106 ) and a lower sense electrode 108 (interchangeably referred to herein as the lower left sense (LLS) electrode 108 ). The right proof mass 104 is between an upper sense electrode 110 (interchangeably referred to herein as the upper right sense (URS) electrode 110 ) and a lower sense electrode 112 (interchangeably referred to herein as the lower right sense (LRS) electrode 112 ).
[0019] The left proof mass 102 is separated from the ULS electrode 106 by a gap (G ULS ) which defines a capacitance that is dependent upon the separation distance between the left proof mass 102 and the ULS electrode 106 . Similarly, the left proof mass 102 is separated from the LLS electrode 108 by a gap (G LLS ) which defines a capacitance that is dependent upon the separation distance between the left proof mass 102 and the LLS electrode 108 . Changes in the capacitances associated with the gaps G ULS and G LLS , caused by linear acceleration or rotation is detectable.
[0020] The right proof mass 104 is separated from the URS electrode 110 by a gap (G URS ) which defines a capacitance that is dependent upon the separation distance between the right proof mass 104 and the URS electrode 110 . Similarly, the right proof mass 104 is separated from the LRS electrode 112 by a gap (G LRS ) which defines a capacitance that is dependent upon the separation distance between the right proof mass 104 and the LRS electrode 112 . Changes in the capacitances associated with the gaps G URS and G LRS , caused by linear acceleration or rotational movement, is detectable.
[0021] The proof masses 102 , 104 are capacitively coupled to drive electrodes (not shown) which impart a “back-and-forth” motion to the proof masses 102 , 104 as an alternating current (AC) voltage is applied to the drive electrodes. The drive electrodes cause the proof masses 102 , 104 to oscillate back and forth in resonance along a drive axis (the illustrated x axis). The drive axis and the y axis define an in-plane motion of the proof masses 102 , 104 . The relative direction of motion of the left proof mass 102 , as denoted by the direction vector 114 , is opposite from the direction of motion of the right proof mass 104 , as denoted by the direction vector 116 , during one half cycle of the resonant motion. Thus, the proof masses 102 , 104 are illustrated as moving away from each other in FIG. 1 . During the next half cycle of the resonant motion, the proof masses 102 , 104 move towards each other. It is appreciated that embodiments of the inertial sensor 100 may be implemented in MEMS based devices having various configurations of drive electrodes.
[0022] FIG. 2 is a conceptual perspective view of electrodes and proof masses for an alternative embodiment of the inertial sensor 100 . Electrode groups 202 , 204 are oriented above and below the proof masses 102 , 104 , respectively. Electrodes 206 , 208 , 210 and 212 are oriented above and substantially the same distance from the left proof mass 102 as illustrated, and define the gap G ULS . Electrodes 214 , 216 , 218 and 220 are oriented below and substantially the same distance from the left proof mass 102 as illustrated, and define the gap G LLS . Electrodes 222 , 224 , 226 and 228 are oriented above and substantially the same distance from the right proof mass 104 as illustrated, and define the gap G URS . Electrodes 230 , 232 , 234 and 236 are oriented below and substantially the same distance from the right proof mass 104 as illustrated, and define the gap G LRS . In alternative embodiments, the electrodes may be positioned at different distances from their respective proof masses. In other embodiments, arrays of electrodes or a plurality of electrodes may be used to apply one or more of the rebalancing forces described herein.
[0023] Opposing electrodes form electrode pairs. For example, electrodes 206 and 214 form an electrode pair. Electrode pairs may be operated in relation to each other, as described in greater detail below. Other electrode pairs include electrodes 208 and 216 , electrodes 210 and 218 , electrodes 212 and 220 , electrodes 222 and 230 , electrodes 224 and 232 , electrodes 226 and 234 , and electrodes 228 and 236 . A pair of selected electrodes for each of the proof masses 102 , 104 corresponds to the above-described electrodes 106 and 108 , or electrodes 110 and 112 . The gaps between the proof mass and each of the electrodes of an electrode pair, when a voltage is applied there across, results in a detectable capacitance. For example, the gap G ULS between the electrode 208 and the proof mass 102 results in a first capacitance. Similarly, the gap G LLS between the proof mass 102 and the electrode 216 results in a second capacitance. When the proof mass 102 moves, the above described first and second capacitances change. The capacitance changes may be determined by sensing the change in a current from an amplifier (not shown) coupled to the electrode 208 and/or the electrode 216 .
[0024] FIG. 3 is a conceptual side view of an embodiment of the inertial sensor 100 . Here, the proof masses 102 , 104 are illustrated as aligned with each other along the x axis. A flexure 302 supports the left proof mass 102 between the gaps G ULS and G LLS . A flexure 304 supports the right proof mass 104 between the gaps G URS and G LRS . The flexures 302 and 304 are attached to anchor 306 . In this exemplary embodiment, anchor 306 is attached to the lower substrate 308 , although the anchor 306 may be attached to the upper substrate 310 , or may be attached to both substrates 308 , 310 , in alternative embodiments. The flexures 302 , 304 are flexible members that have spring-like characteristics such that when the proof masses 102 , 104 are driven by the drive electrodes (not shown), the proof masses 102 , 104 will resonate.
[0025] In other embodiments, the anchor 306 may be attached to the upper substrate 310 . Some embodiments may employ a plurality of flexures to couple the proof masses 102 , 104 to various anchor points in the MEMS device. In some embodiments, the flexures 302 , 304 may be connected to different anchors.
[0026] In the exemplary embodiment of the inertial sensor 100 , the proof masses 102 , 104 are suspended such that the gaps G ULS and G LLS , and the gaps G URS and G LRS , are equal to each other. Accordingly, the upper and lower capacitances associated with the proof masses 102 , 104 and the illustrated electrodes are substantially equal (with respect to each other). For example, assuming that the surface areas and other characteristics of the electrodes 206 , 214 , 228 , and 236 are substantially the same, the capacitance between the electrode 206 and the left proof mass 102 , the capacitance between the electrode 214 and the left proof mass 102 , the capacitance between the electrode 228 and the right proof mass 104 , and the capacitance between the electrode 236 and the right proof mass 104 , are substantially the same. In alternative embodiments, the capacitances may be different from each other.
[0027] A linear acceleration in a direction along the illustrated z axis causes the proof masses 102 , 104 to move together in the same direction and at substantially the same rate and/or distance. This movement is referred to herein as movement in a “common mode.” The common mode movement of the proof masses 102 , 104 causes substantially the same change in the electrode-to-proof mass capacitance of electrode pairs across the gaps G ULS and G URS , and substantially the same change in the electrode-to-proof mass capacitance of the electrode pairs across gaps G LLS and G LRS . That is, assuming that the upper and lower gaps (G URS , G LRS , G ULS , and G URS ) are the same (i.e.: balanced), the magnitudes of the changed capacitance of electrode pairs across the gaps G ULS and G URS , and the magnitudes of the changed capacitance of the electrode pairs across gaps G LLS and G LRS , are substantially the same. If the gaps G ULS , G LLS , G URS , and G LRS , are unbalanced, the upper capacitances vary substantially the same amount, and the lower capacitances vary substantially the same amount, since the forces which move the proof masses 102 , 104 that result in the change of these capacitances are nearly equal. Linear acceleration can be determined from the sensed common mode changes in capacitance.
[0028] Further, a rotation in a direction around the illustrated y axis causes the proof masses 102 , 104 to move in opposite directions and at substantially the same rate and/or distance in the z direction. This movement is referred to herein as movement in a “differential mode.” The differential mode movement of the proof masses 102 , 104 is caused by Coriolis forces. This differential mode movement of the proof masses 102 , 104 (movement in opposite directions) causes substantially the same magnitudes of change in the electrode-to-proof mass capacitance of electrode pairs across the gaps G ULS and G LRS , and substantially the same magnitudes of change in the electrode-to-proof mass capacitance of the electrode pairs across gaps G LLS and G URS . Rotation can be determined from the sensed differential mode changes in capacitance.
[0029] As noted above, embodiments of the inertial sensor 100 provide decoupling between acceleration sensing and rotation sensing so that rotation and acceleration are independently sensed and determined. In the preferred embodiment, the quadrature forces, which are ninety degrees out-of-phase from the Coriolis forces, are also decoupled from the acceleration and Coriolis forces. Accordingly, rebalancing forces for linear acceleration, Coriolis, and/or quadrature forces are separately applied to electrode pairs to maintain the position of the proof masses 102 , 104 in a fixed position such that the capacitances associated with the respective electrode pairs across gaps G ULS , G LLS , G URS , and G LRS , are substantially matched. Thus, when an unbalance between the positions of the proof masses 102 , 104 occurs (detectable from the changes in the electrode-to-proof mass capacitances of the electrode pairs across the gaps G ULS , G LLS , G URS , and G LRS ), rebalancing forces operate to self center the proof masses 102 , 104 .
[0030] A Coriolis rebalancing force is applied to proof mass 102 by a selected electrode pair. A Coriolis rebalancing force is also applied to proof mass 104 by another selected electrode pair. The applied Coriolis rebalancing force self centers the proof masses 102 , 104 during a rotation of the inertial sensor 100 . The magnitude of the required Coriolis rebalancing force corresponds to the amount of rotation. Similarly, an applied linear acceleration rebalancing forces self center the proof masses 102 , 104 during a linear acceleration of the inertial sensor 100 . The magnitude of the required linear acceleration rebalancing force corresponds to the amount of linear acceleration. Since the linear acceleration rebalancing force is provided by a direct current (DC) voltage applied to selected electrode pairs, the linear acceleration rebalancing force can be differentiated from the Coriolis rebalancing force. That is, because a linear acceleration (which induces a time varying acceleration force in the z-axis) is different from a rotation (which induces a force that is modulated at the drive frequency of the proof masses 102 , 104 ), the linear acceleration rebalancing force and the Coriolis rebalancing force can be separately determined.
[0031] FIG. 4 is a conceptual side view of an embodiment of the inertial sensor 100 with applied initialization rebalancing forces 402 , illustrated as vectors 402 . Selected electrodes may be operated to exert an initialization rebalancing force to its respective proof mass 102 , 104 . Accordingly, the gaps G ULS , G LLS , G URS , and G LRS , may be set to be equal to each other, or set to a desired value.
[0032] For example, as conceptually illustrated in FIG. 4 , during fabrication of an inertial sensor 100 , the left proof mass 102 may not be in its designed ideal position 404 between the electrodes. Here, the left proof mass 102 is illustrated in a non-ideal position 406 such that the gaps G ULS and G LLS are not substantially equal. The non-ideal position 406 of the left proof mass 102 , even though acceptable from a fabrication perspective, may be sufficiently different from the ideal position 404 as a result of design and/or fabrication tolerances so as to impart inaccuracies in the detection of linear accelerations and/or rotational movement. Initialization rebalancing forces, illustrated as vectors 402 , may be applied by one or more selected electrodes to reposition the left proof mass 102 to, or very near to, its designed ideal position 404 . The initialization rebalancing forces may be equal, or may be unique, depending upon the amount of initialization rebalancing required to position a proof mass into its ideal position. Preferably, the initialization rebalancing forces result from DC biases applied to the selected electrodes. The initialization rebalancing forces may be determined prior to use of the inertial sensor 100 , such as by bench testing after fabrication.
[0033] FIG. 5 is a conceptual side view of an embodiment of the inertial sensor 100 with an applied linear acceleration, denoted by the acceleration vectors 502 (corresponding to a movement in the negative z axis direction). Inertial forces (illustrated as vectors 504 ) are exerted on the proof masses 102 , 104 . Accordingly, the proof masses 102 , 104 are moved towards the upper substrate 310 during the period of acceleration. The flexures 302 , 304 will operate to return the proof masses 102 , 104 to their initial positions (see FIG. 3 ) when the acceleration ceases.
[0034] The above-described common mode movement of the proof masses 102 , 104 causes substantially the same change in the electrode-to-proof mass capacitance of electrode pairs across the gaps G ULS and G LLS , and the electrode pairs across the gaps G URS and G LRS , respectively. That is, the magnitude of the changed electrode-to-proof mass capacitance of electrode pairs across the gaps G ULS and G URS , and the magnitude of the changed electrode-to-proof mass capacitance of electrode pairs across the gaps G LLS and G LRS , are substantially the same. In response to the movement of the proof masses 102 , 104 , a linear acceleration rebalancing force may be applied via selected electrode pairs to reposition the proof masses 102 , 104 back to their original position. Linear acceleration can be determined from the amount of the applied linear acceleration rebalancing force and/or from the sensed common mode changes in capacitance.
[0035] FIG. 6 is a conceptual side view of an embodiment of the inertial sensor 100 with an applied rotation, denoted by the rotation vector 602 , (corresponding to a rotation movement around the y axis). Inertial forces, illustrated as vectors 604 and 606 , are exerted on the proof masses 102 , 104 , respectively. Accordingly, the proof mass 102 is moved towards the upper substrate 310 during the period of rotation and the proof mass 104 is moved towards the lower substrate 308 during the period of rotation. The flexures 302 , 304 will operate to return the proof masses 102 , 104 to their initial positions (see FIG. 3 ) when the rotation ceases.
[0036] The above-described differential mode movement of the proof masses 102 , 104 causes a detectable change in the electrode-to-proof mass capacitance of electrode pairs across the gaps G ULS , G LLS , G URS , and G LRS . The magnitude of the changed electrode-to-proof mass capacitance of electrode pairs across the gaps G ULS and G LRS , and the magnitude of the changed electrode-to-proof mass capacitance of electrode pairs across the gaps G LLS and G URS , are substantially the same (assuming initial balancing of the gaps G URS , G LRS , G ULS , and G URS ). In response to the movement of the proof masses 102 , 104 , a Coriolis rebalancing force may be applied via selected electrode pairs to reposition the proof masses 102 , 104 back to their original position. Rotation can be determined from the applied Coriolis rebalancing force and/or from the sensed differential mode changes in capacitance.
[0037] FIG. 7 illustrates applied and sensing voltages for a portion of an embodiment of the inertial sensor 100 illustrated in FIG. 1 . The voltages V ULS , V LLS , applied by the electrode pair 106 and 108 , and the voltages V URS , and V LRS , applied by the electrode pair 110 and 112 , correspond in part to the linear acceleration rebalancing force.
[0038] The applied voltages have three components that provide three functions, linear acceleration rebalancing, rotation sense biasing, and acceleration sense pickoff. The applied upper left sense plate voltage (V ULS ) may be defined by equation (1) below:
[0000] V ULS =−V SB −V A +V p sin( opt ) (1)
[0000] where V SB is the applied voltage of the sense bias (a DC bias voltage), where V A is the voltage of the applied linear acceleration rebalancing force, where V p is an applied AC pick off voltage, and where ω p is the frequency of the applied AC pick off voltage V p . The current i SPO results from imbalances in the position of the proof masses 102 , 104 .
[0039] The applied lower left sense plate voltage (V LLS ), the applied upper right sense plate voltage (V URS ), and the applied lower right sense plate voltage (V LRS ), may be defined by equations (2), (3), and (4), respectively, below:
[0000] V LLS =V SB −V A −V p sin(ω p t ) (2)
[0000] V URS =V SB +V A +V p sin(ω p t ) (3)
[0000] V LRS =−V SB +V A −V p sin(ω p t ) (4)
[0040] An amplifier system 702 is communicatively coupled to detect voltages and/or currents from the proof masses 102 , 104 . The output of the amplifier system 702 corresponds to the sensed pick off voltage, V SPO . V SPO may be defined by equation (5) below.
[0000] V SPO =[V Ω ·cos(ω m t )]+[ V Q ·sin(ω m t )]+[ V CM ·sin(ω p t )] (5)
[0000] where V Ω is the portion of V SPO that is proportional to the rotation motion, where V Q is the quadrature component of V Ω , where V CM is the portion of V SPO that is proportional to the common mode motion (caused by the linear acceleration), and where ω m is the applied motor frequency.
[0041] FIG. 8 illustrates applied and sensing voltages for the embodiment of the inertial sensor 100 . Included are the above-described applied voltages V ULS , V LLS , V URS , and V LRS , corresponding to the linear acceleration rebalancing force, which are applied by the electrode pair 208 , 216 to proof mass 102 , and by the electrode pair 226 , 234 to proof mass 104 . Other embodiments may apply the linear acceleration rebalancing force using different selected electrodes. In some embodiments, the electrodes 208 , 216 , 226 , and 234 may be used to inject currents (or voltages) used for sensing common mode movement and/or differential mode movement of the proof masses 102 , 104 .
[0042] The electrode pair 210 , 218 provides a Coriolis rebalancing force to the proof mass 102 . Similarly, the electrode pair 224 , 232 applies a Coriolis rebalancing force to the proof mass 104 . Preferably, the Coriolis rebalancing force applied to the proof mass 102 is opposite in direction and of equal magnitude to the Coriolis rebalancing force applied to the proof mass 104 . Other embodiments may apply the Coriolis rebalancing force using different selected electrodes.
[0043] The Coriolis rebalancing force, corresponding to V CUL , applied by electrode 210 may be defined by equation (6) below:
[0000] V CUL =V COR sin(ω m t /2) (6)
[0000] where V COR is a Coriolis voltage, and where ω m t/2 is the one half of the frequency of the motor frequency of proof masses 102 , 104 .
[0044] The Coriolis rebalancing force, corresponding to V CLL , applied by electrode 218 , the Coriolis rebalancing force, corresponding to V CUR , applied by electrode 224 , and the Coriolis rebalancing force, corresponding to V CLR , applied by electrode 232 , may be defined by equations (7), (8), and (9), respectively, below:
[0000] V CLL =V COR cos(ω m t/ 2) (7)
[0000] V CUR =V COR cos(ω m t/ 2) (8)
[0000] V CLR =V COR sin(ω m t/ 2) (9)
[0045] Some embodiments may apply optional quadrature rebalancing forces via the optional electrodes 206 , 214 , 228 , and 236 . The quadrature rebalancing forces are proportional to the induced motor motion of the proof masses 102 , 104 . In the exemplary embodiments illustrated in FIGS. 2-9 , four electrodes are illustrated (at each end of the proof masses 102 , 104 ) that are used for the application of quadrature rebalancing forces. In alternative embodiments, a single electrode pair for each of the proof masses 102 , 104 may be used to apply quadrature rebalancing forces. The single pair of quadrature rebalancing electrodes may be placed in any suitable position with respect to its proof masse 102 , 104 . In alternative embodiments, quadrature rebalancing electrodes are optional or are not used.
[0046] FIG. 9 illustrates applied voltages and sensing voltages for an alternative embodiment of the inertial sensor 100 . The electrodes 208 , 216 , 226 , and 234 are coupled to pick off amplifier systems 902 , 904 , 906 , and 908 , respectively, to sense or pick off voltages at their respective electrodes. This embodiment allows compensation of parasitic signals injected into the proof masses 102 , 104 , which may result in undesirable applied parasitic forces. That is, parasitic coupling effects between the rotational forces and the linear acceleration forces may be mitigated since the frequency of parasitic terms will be higher (ω p +ω m /2).
[0047] The amplifier system 902 outputs a signal V ULSP . The amplifier systems 904 , 906 , and 908 , output the signals V LLSP , V URSP , and V LRSP , respectively. Rotational output, V RATE , may be derived from the output of the amplifier systems 902 , 904 , 906 , and 908 , in accordance with equation (10), below:
[0000] V RATE =V ULSP +V LRSP −V LLSP −V URSP (10)
[0048] FIG. 10 is a block diagram illustrating an exemplary implementation of a processing system 1002 coupled to an embodiment of the inertial sensor 100 . In an exemplary embodiment, the processing system is a digital signal processing (DSP) electronics system. The processing system 1002 may be implemented as an analog, as a digital system, or a combination thereof, and may be implemented as software, hardware, or a combination of hardware and software, depending upon the particular application.
[0049] The amplifier system 702 provides the sensed pick off voltage, V SPO , to the processing system 1002 . Demodulators 1004 , 1006 and 1008 demodulate V SPO by stripping off the AC portions of V SPO . The 90 degree clock applied to demodulator 1004 and the 0 degree clock applied to demodulator 1006 correspond to a multiplied motor signal at different phases (90 degrees and 0 degrees, respectively).
[0050] The low pass filter 1010 processes the output of the demodulator 1004 and outputs a Coriolis output signal to a proportional-integral-derivative (PID) controller 1012 . A low pass filter 1014 and a PID controller 1016 process the output of the demodulator 1004 and outputs a quadrature output signal. A low pass filter 1018 and a PID controller 1020 process the output of the demodulator 1008 and outputs an acceleration output signal corresponding to the common mode imbalance in capacitance. The output signals are used to generate the outputs V ULS , V LLS , V URS , and V LRS , corresponding to the above-described linear acceleration rebalancing force, and are used to generate the outputs V CUL , V CLL , V CUR , and V CLR , corresponding to the above-described Coriolis rebalancing force.
[0051] Embodiments of the inertial sensor 100 , operable to sense and determine linear acceleration and rotation, may be incorporated into an inertial measurement unit. Since one inertial sensor 100 sense linear acceleration and rotation, three inertial sensors 100 may be used to construct one inertial measurement unit rather than the three gyroscopes and the three accelerometers used in a conventional inertial measurement unit. Accordingly, costs and/or size may be reduced since fewer components are used.
[0052] While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.
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A Micro-Electro-Mechanical Systems (MEMS) inertial sensor systems and methods are operable to determine linear acceleration and rotation. An exemplary embodiment applies a first linear acceleration rebalancing force via a first electrode pair to a first proof mass, applies a second linear acceleration rebalancing force via a second electrode pair to a second proof mass, applies a first Coriolis rebalancing force via a third electrode pair to the first proof mass, applies a second Coriolis rebalancing force via a fourth electrode pair to the second proof mass, determines a linear acceleration corresponding to the applied first and second linear acceleration rebalancing forces, and determines a rotation corresponding to the applied first and second Coriolis rebalancing forces.
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CROSS REFERENCE TO RELATED APPLICATION
This application claims priority under 35 U.S.C. Sec. 119(e) of U.S. Provisional Patent Application No. 61/484,017 filed May 9, 2011, titled Method of Using Core Engine to Extend Radio System Frequency, and incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to radio communications systems, and more particularly to extending the upper frequency limit of communications radios or transceivers.
2. Discussion of the Known Art
Typically, radio frequency (RF) transceivers constructed for use in the Joint Tactical Radio System (JTRS) have an upper operating frequency limit of about 2 GHz. This limit is not sufficient to support new and emerging wideband networking waveforms such as, e.g., Communication Data Link (CDL) and IEEE 802.16 WiMAX, however. Such waveforms may require the upper frequency limit of a transceiver to be extended to as high as 6 GHz.
U.S. Pat. No. 6,549,082 (Apr. 15, 2003) describes a high frequency oscillator. A reference oscillator in the form of a digital controlled frequency synthesizer with an external tank circuit, operates in a range of 1.25 to 1.5 GHz. A phase-locked loop circuit of the synthesizer is combined with the reference oscillator in an integrated circuit, preferably using a Bipolar CMOS (BiCMOS) silicon/germanium process. According to the patent, a tuned output range of 5 to 6 GHz may be provided by using a dividing factor of four.
U.S. Pat. No. 7,313,368 (Dec. 25, 2007) discloses a transceiver architecture including a dual-band, single frequency synthesizer for wireless communication in the 2.4 GHz and 5 GHz International industrial, scientific, and medical (ISM) bands. A high frequency integrated circuit down converts a received multi-mode frequency signal, and a base frequency decoding circuit performs the processes of up-sampling and emitting a signal so as to transmit/receive a dual band signal by using the single frequency synthesizer.
Notwithstanding the above, there is a need to extend the upper frequency limit of existing tactical radio systems or transceivers from 2 GHz to 6 GHz so that the systems can support the new and emerging wideband networking waveforms transmitted above 2 GHz in the RF spectrum, while confining the space occupied by the extended systems within an even smaller volume than that allotted for the existing systems.
SUMMARY OF THE INVENTION
According to the invention, a communications radio or transceiver having an extended upper operating frequency limit, includes a first intermediate frequency (IF) conversion stage constructed and arranged for receiving and down converting a radio frequency (RF) input signal to a first IF signal, and a second IF conversion stage constructed and arranged for down converting the first IF signal to a second IF signal.
The first and the second conversion stages each have adjustable first and second attenuators, a serial peripheral interface (SPI) for controlling the attenuators in response to command words, a mixer coupled to an output of the second attenuator, and a buffer for applying a local oscillator (LO) signal to an input of the mixer. Each conversion stage is in the form of an integrated circuit chip. Component devices of each chip and electrical connections between the components, are dimensioned so that the chip has an upper frequency limit of at least 6 GHz.
Thus, “System-on-a-chip” and other size reduction techniques are employed to provide a radio having a 6 GHz upper frequency limit, and in a much smaller form factor compared to existing radios. Such techniques include the use of switched and stored circuit paths among receiver and transmitter functions.
For a better understanding of the invention, reference is made to the following description taken in conjunction with the accompanying drawing and the appended claims.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
FIG. 1 is a diagram of a radio frequency (RF) converter chip employed in the present invention, showing certain devices integrated in the chip;
FIG. 2 is a block diagram of a serial peripheral interface (SPI) in the chip of FIG. 1 ;
FIG. 3 shows the relative size of a single core engine RF circuit card constructed according to the invention at the right, with respect to a pair of prior RF circuit cards at the left;
FIG. 4 shows a signal path through the inventive circuit card when tuned to receive a signal at 1.7 GHz; and
FIG. 5 shows a signal path through the inventive circuit card when tuned to receive a signal at 5.9 GHz.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a functional block diagram of a high dynamic range RF converter chip 10 developed by and available from BAE Systems Microelectronics Group. By integrating RF switches, amplifiers, filters, and mixers on a die with short connections between components to reduce parasitic capacitance and improve high speed electrical performance, the chip 10 has an upper operating frequency limit of 6 GHz.
Devices integrated on the chip 10 include, inter alia, a Gilbert cell mixer 12 with a transimpedance amplifier (TIA) input stage 14 as disclosed in U.S. Pat. No. 8,089,309 (Jan. 3, 2012), and thermometer coded attenuators 16 , 17 , as described in U.S. Pat. No. 7,911,293 (Mar. 22, 2011). Both of the mentioned patents are incorporated by reference in their entireties. The attenuators 16 , 17 , exhibit low phase discontinuity between gain steps and monotonicity is assured. The chip 10 also has a high speed CMOS serial peripheral interface (SPI) 18 , shown in detail in FIG. 2 , and an integrated local oscillator (LO) buffer 20 that allows the chip 10 to be driven with a very low nominal −15 dBm LO signal level. The attenuators 16 , 17 are controlled by the SPI 18 .
In addition, switched filters may be integrated into the converter chip 10 for image suppression, so that the filters are also controlled via the SPI 18 . Such filters would reduce the amount of attenuation required from externally provided image reject filters, and help to avoid the generation of spurious signals.
High or low side LO frequency signals can be used to down convert a 2 MHz to 6 GHz single ended RF signal 22 that is input to the chip 10 , to an optimized intermediate frequency (IF) of up to 1.5 GHz. IF bandwidths from very narrow to more than 100 MHz can be realized by using an appropriately selected off-chip filter. A balun 24 converts a differential IF output signal from the Gilbert cell mixer 12 to a single ended IF signal to interface with the back end of a transceiver, thus maintaining the benefits of the fully balanced mixer 12 . Control registers are memory mapped so that a companion second converter chip 10 may be controlled via the common serial interface 18 .
FIG. 3 shows, at the left, two RF circuit cards 30 , 32 , that form part of a core engine (CE) of an existing JTRS transceiver having an upper frequency limit of 2 GHz. By contrast, a single RF circuit card 34 constructed according to the present invention at the right of FIG. 3 , can replace the functionality of the two cards 30 , 32 , in a transceiver. By employing two of the converter chips 10 on the card 34 as shown in FIGS. 4 and 5 , the size of the card can be made substantially smaller than either one of the cards 30 , 32 . Moreover, the chips 10 enable the operating frequency range of the transceiver to be extended well beyond the present JTRS limit of 2 GHz.
Advantages of the inventive RF circuit card 34 with respect to the prior cards 30 , 32 , include:
1. A controlled 30 dB range of attenuation for each of the two attenuators 16 , 17 , on the converter chip 10 , for a total range of controlled attenuation of 60 dB.
2. A minimum attenuator step size of 0.125 dB with +/−0.2 dB accuracy across the 6 GHz range of transceiver operation. See the above mentioned U.S. Pat. No. 7,911,293, incorporated by reference.
3. An input third intercept point (IP3) of +20 dBm.
4. A noise figure of 13 dB or less.
5. Receiver P1 dB out>+5 dBm
6. The SPI interface 18 in each chip 10 enables digital control of all the chip functions.
7. The transimpedance amplifier input stage mixers on each chip 10 provide high linearity. See the above mentioned U.S. Pat. No. 8,089,309, incorporated by reference.
8. Lower power consumption.
9. A lower parts count, and higher integration of components inside each chip 10 .
10. Lower LO drive due to the built in buffer amplifier 20 in each chip 10 . Lower LO drive means lower power consumption relative to the prior CE in which a drive of +10 dBm was required. Also, less interference and harmonics are generated with the reduced LO drive power.
11. Digital automatic gain control (AGC) in each chip ensures reliable digital control over a 60 dB dynamic range, without external digital-to-analog converters and signal paths leading to discrete components which can produce interference. The thermometer controlled attenuators in each chip 10 ensure proper attenuation at temperature extremes, thus removing or relieving the need for elaborate temperature calibration tables.
12. A high power IF amplifier in the back end of the receiver (Rx) chain reduces the need for a high power amplification stage before an analog-to-digital (ADC) section. The prior CE uses a variable gain amplifier which represents a tradeoff between gain and IP3, a non-desirable situation when detecting OFDM waveforms.
13. The transmitter (Tx) chain on the card 34 is more isolated overall from the Rx chain. In the prior CE, components and stages had to be shared in order to allow the radio to be packaged and mounted within the specified space. Additional isolation is also obtained by physically separating the two converter chips 10 which function as first and second IF stage mixers on the card 34 . And since the size of each chip package may be as small as 3 mm×3 mm, component sharing is not necessary and more isolation between the Tx and the Rx chains is achieved.
FIGS. 4 and 5 are schematic diagrams of the RF circuit card 34 showing the chips 10 employed as first and second IF stage converters. Examples 1 and 2, below, describe the operation of the card 34 including the chips 10 and other components when the CE is tuned to an RF input signal 42 of, e.g., 1.7 GHz ( FIG. 4 ), and 5.9 GHz ( FIG. 5 ). In addition to the chips 10 , other features that allow the receive frequency range to be extended are separately packaged, commercial off the shelf (COTS) components such as RF switches and surface acoustic wave (SAW) RF bandpass filters. The transmit frequency range is extended to 6 GHz by the use of separate GaN RF pre-amplifier and final amplifier gain stages.
EXAMPLE ONE
FIG. 4
Operation of Rx Chain to Receive and Down Convert a 1.7 GHz RF Signal
FIG. 4 is a schematic block diagram of the inventive RF circuit card 34 , illustrating the operation of a Rx chain 40 in the card when an associated CE module or transceiver is tuned to receive a RF signal 42 at a frequency of 1.7 GHz.
A field programmable gate array (FPGA) in the transceiver is configured to accept a command for tuning the receiver to a desired frequency, for example, 1.7 GHz. A 1 to 2 GHz filter table is accessed, the appropriate 1000-2000 MHz front end (FE) filter 44 is selected from among a stack 45 of, e.g., five SAW filters, and the filter 44 is switched into the Rx chain 40 by a pair of electronically controlled switches shown in FIG. 4 . A control value that tunes the filter 44 to 1.7 GHz is recalled, and the value is applied to a tuning port of the FE filter 44 by a DAC.
A high IP3 low noise amplifier (LNA) 46 appropriate for the desired frequency of 1.7 GHz, is selected from among a bank of two LNAs and the amplifier 46 is switched into the Rx chain 40 . A first one of the chips 10 functions as a first IF conversion stage 48 , and the chip receives a word via its SPI 18 corresponding to a nominal receive AGC level for tuning each of the internal attenuators 16 , 17 , over a 30 dB range. The initial AGC value is based on an estimate of the SNR made at back end processing stages of the receiver, and is written in a calibration table that is preferably stored in a ferromagnetic RAM (FRAM) of the receiver.
A fractional synthesizer 50 is configured to produce a first local oscillator signal to drive the mixer 12 in the first conversion stage chip 10 . A preferred synthesizer 50 is type ADC 4350 available from Analog Devices, or equivalent. The synthesizer 50 is tuned to produce the first LO signal at a frequency equal to a first intermediate frequency (IF) specified for the transceiver (e.g., 455 MHz) plus the frequency of the RF signal 42 to be received, i.e., 455+1700=2155 MHz. A 225-500 MHz image reject filter 52 is switch-selected from a stack 53 of two SAW filters following the first conversion stage 48 . The filter 52 is then tuned to the specified first IF signal frequency of 455 MHz, thus allowing the down converted RF signal 42 to pass while rejecting all undesired sidebands.
The output of the filter 52 is operatively connected through a switch to an input of a second chip 10 that functions as a second IF conversion stage 60 . A fractional synthesizer 62 (e.g., type ADC 4350 ) is configured to produce a second LO signal for driving the mixer 12 in the second chip 10 at such a frequency so that the difference between the first IF of 455 MHz and the frequency of the second LO signal is equal to a second IF (e.g., 70 MHz) specified for the transceiver. The built in 30 dB attenuators 16 , 17 , of the second chip 10 are then tuned to a precalibrated AGC value to produce a particular SNR for a detected baseband waveform.
After the second IF conversion stage 60 , an appropriate bandwidth (BW) filter that is centered at the second IF frequency of 70 MHz, is selected from among a stack 70 of SAW filters. The stack 70 may include, e.g., four filters having bandwidths of 25 KHz, 1.2 MHz, 5 MHz, and 30 MHz. The filter selection is made in response to a control command from a waveform FPGA in the transceiver, and corresponds to the bandwidth of a particular waveform to be detected from the downconverted RF signal 42 . Following the filter stack 70 , a single ended to differential high IP3 gain stage 80 operates to amplify the BW filtered IF signal, and to buffer the signal before it is applied to an ADC 90 for further processing at the back end of the transceiver.
EXAMPLE TWO
FIG. 5
Operation of Rx Chain to Receive and Down Convert a 5.9 GHz RF Signal
When the transceiver FPGA accepts a command to tune the radio to 5.9 GHz, a 4-6 GHz stripline tunable filter table is accessed, an appropriate 4 GHz-6 GHz FE filter 92 is selected, and a DAC control value that is operative to tune the filter 92 to 5.9 GHz is recalled. The control value is applied to the tuning port of the FE filter 92 , and a proper LNA 96 for the operating frequency is switch selected.
The chip 10 of the first conversion stage 48 is given a word via its SPI 18 corresponding to a nominal receive AGC level for tuning each of the internal attenuators 16 , 17 , over a 30 dB range. The initial AGC value is based on an estimate of the SNR at the back end processing of the transceiver and may be part of a calibration table stored in the FRAM of the receiver. The fractional synthesizer 50 of the first conversion stage 48 is tuned to output a LO signal at a frequency of the first IF (455 MHZ) plus the frequency of the desired RF signal (5900 MHZ), or 6355 MHZ. The 225-500 MHZ image reject filter 52 that follows the first conversion stage 48 is then tuned to the first IF of 455 MHZ, thus allowing the down converted RF signal 42 to pass while rejecting all undesired sidebands.
The output of the filter 52 is applied through a switch to an input of the second chip 10 that functions as the second IF conversion stage 60 . The synthesizer 62 is tuned to output a LO signal to the mixer in the chip 10 at such a frequency so that the difference between the first IF of 455 MHz and the frequency of the second LO signal is equal to the second IF (e.g., 70 MHz) specified for the transceiver. The built in 30 dB attenuators 16 , 17 , of the second chip 10 are then tuned to a precalibrated AGC value to produce a particular SNR for a detected baseband waveform.
As in Example One, after the second IF conversion stage 60 , an appropriate bandwidth (BW) filter centered at the second IF frequency of 70 MHz is selected from among the stack 70 of SAW filters whose bandwidths may include, e.g., 25 KHz, 1.2 MHz, 5 MHz, and 30 MHz. The filter selection is made in response to a control command from a waveform FPGA in the transceiver, and corresponds to the bandwidth of the particular waveform to be detected from the RF signal 42 . Following the filter stack 70 , the single ended to differential high IP3 gain stage 80 amplifies the BW filtered IF signal, and buffers the signal before it enters to an ADC 90 for further processing.
Those skilled in the art will appreciate that the provision of the two IC converter chips 10 with integrated amplifiers, mixers, and attenuators in the Rx chain of a transceiver, together with the application of GaN technology in the transmit chain, can extend the upper operating frequency of the radio as high as 6 GHz and thus support important new and emerging wideband networking waveforms.
While the foregoing represents preferred embodiments of the invention, those skilled in the art will understand that various changes, modifications, and additions may be made without departing from the spirit and scope of the invention, and that the present invention includes all such changes and modifications as are within the scope of the following claims.
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A communications radio or transceiver having an extended upper operating frequency limit of at least 6 GHz. The radio includes a first IF conversion stage for receiving and downconverting a RF input signal to a first IF signal, and a second IF conversion stage for downconverting the first IF signal to a second IF signal. The first and the second conversion stages each have adjustable first and second attenuators, a serial peripheral interface (SPI) for controlling the attenuators in response to command words, a mixer coupled to an output of the second attenuator, and a buffer for applying a local oscillator (LO) signal to an input of the mixer. Each conversion stage is in the form of an integrated circuit chip. Component devices of each chip and electrical connections between the components, are dimensioned so that the chip has a 6 GHz upper frequency limit.
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[0001] The present invention relates to a surgical joint implant and a bone-mountable rig for correct drilling and insertion of such a surgical joint implant. The implant according to the invention is intended for repair of the surface of a joint of a human or animal.
[0002] It is intended that the implants of the present invention may be tailor-made to the patient and the damage to her joint to be repaired. This individually shaped implant can be made by the method described in Application No. PCT/EP2014/064749, reference No. IPQ6028, filed by the same applicant and having the same filing date. This co-pending application filed together herewith is hereby incorporated by reference.
[0003] The advantages of implants over knee replacement have stimulated a further development of smaller implants that can be implanted with less invasive surgery. In this development there has also been an effort to achieve small joint implants, suitable for repair of a small cartilage injury that have a minimal influence on the surrounding parts of the joint. In the current development, such small implants are designed with an implant body that may be formed as a mushroom cap with a hard surface to face the articulating side of the joint and a bone contacting surface engaging the bone below the damaged part of cartilage. The shape and the curvature of the articulating surface of the implant may be designed to be a reconstitution of the shape and the curvature of the part of the joint when it was undamaged. Such implants are usually designed as mushrooms with an implant body or head and with a peg or a rod projecting from the bone contacting side of the implant body for anchoring the implant into the bone.
[0004] WO2007/014164 A2 describes a kit comprising a plurality of small joint implants having different predetermined shapes described as circle, oval, L-shape and triangular shape and tools for placing the implants and a method for placing the implant in a joint, e.g. in the knee or other joints where there is a need for repair of a cartilage and/or bone damage. In this piece of prior art each implant shape has a specific guide tool which corresponds to the shape of the implant.
[0005] The cartilage damage is repaired by choosing the most suitable implant from the different shapes mentioned above. The corresponding guide tool is selected and is used for faster reaming of the area where the implant is to be placed. A drill is used for drilling a hole to accept the post extending from the bone contacting side of the implant. In the end, the implant is placed on the area reamed or drilled out for the implant. Although it is the intention that the guide tool shall be used for the preparation of the placement of the implant it is also said that the use of the guide tool is optional, see passage sections [019, 020].
THE ADVANTAGES OF THE INVENTION
[0006] The aim of the present invention is to solve a complex of difficulties encountered when attempting to repair damaged joints using surgical implants. For a number of different types of joint damage, a circular implant mushroom cap with a central anchoring stem or peg of smaller diameter is preferably used. The deeper small diameter central hole for the central anchoring peg and the shallower larger diameter hole for the implant cap having the new joint repair surface can be accurately drilled at the same time where a circular double drill is preferably used. A double drill has a central small diameter bit and further up a larger diameter drill cutting surface. An example of such a drill used together with the drilling rig of the invention is shown in FIG. 4 . Such drills are commonly used in other areas for inlaid discs and for countersinking screws.
[0007] But the area of the joint damage may not be easily covered by a single circular implant if the damaged area is elongate or is irregular or large in shape. Instead of using a number of separate implants or an implant requiring complicated bone removal techniques, using several different drills and tools, the surgical implant and the rig according to the present invention provide an exceptionally simple solution which also utilizes a single rig anchored in place for the entire pre-drilling and drilling operation. The same double-drill, the same pre drilling guide socket and the same depth adjustment socket is used for all drillings. This is made possible by a rig which permits shifting of the guide socket or adjustment socket from one side to the other side (or the other sides) of the hollow shell interior between drillings. A shiftable interior arcuate wall can also be inserted in each position to provide a complete circular cylinder for holding the pre-drilling guide socket for each drilling.
[0008] According to one embodiment, this will simply create two identical peg holes and an exactly excavated cavity to fit an implant in the form of two intersecting circles of the same diameter. Merely removing the insert wall in the cylindrical interior then creates a shell, already securely rigged in location, for a gauge for the oblong implant with at least two pegs. A handled gauge in the shape of the implant is inserted after drilling to check that the proper drilling depth has been reached. After all drillings have been made and depth checked, the drilling rig is removed.
[0009] The implant should comprise a biocompatible metal, metal alloy, ceramic or polymeric material. More specifically it may comprise any metal or metal alloy used for structural applications in the human or animal body, such as stainless steel, cobalt-based alloys, chrome-based alloys, titanium-based alloys, pure titanium, zirconium-based alloys, tantalum, niobium and precious metals and their alloys. If a ceramic is used as the biocompatible material, it can be a biocompatible ceramic such as aluminium oxide, silicon nitride or yttria-stabilized zirconia. Preferably the articulate surface comprises a cobalt chrome alloy (CoCr) or stainless steel, diamond-like carbon or a ceramic.
[0010] The implant according to one embodiment of the present invention has two parallel pegs of the same nominal diameter, but with one being slightly larger than the diameter of the hole to provide an interference fit. The other peg of the same nominal diameter is very slightly smaller than the diameter of the hole to provide a slide fit. This relationship will provide secure anchoring of the implant by virtue of the interference fit. The slide fit peg will prevent rotation of the implant and will not give rise to problematic stresses between the pegs which might be the case with two interference fits. This implant and rig will also make is easier to insert and make sure that the implant cap seats securely in place against the bottom of the shallow wide hole drilled into the bone. This is very important in making sure that the implant is held securely by bone growth without cavities.
[0011] The present invention also contemplates as a first alternative a surgical implant having two pegs, but it is also contemplated according to the invention an implant having three or more pegs and an implant form comprising three or more intersecting circles. In this case the drill guide insert wall is shifted between three or more different arcuate depressions in the interior of the rig.
SHORT DESCRIPTION OF THE DRAWINGS
[0012] The implant and rig of the invention will be described below with reference to a non-limiting example shown in the accompanying drawings of which,
[0013] FIG. 1 shows a two-pegged implant,
[0014] FIG. 2 shows a rig according to the invention for a two pegged implant. The rig is mounted in place on a femoral condyle.
[0015] FIG. 3 a shows a three-pegged implant having the form of three identical intersecting circles.
[0016] FIG. 3 b shows from above a rig with wall insert for a three-peg implant.
[0017] FIG. 4 shows a double drill for use with the drilling rig according to the invention.
[0018] FIG. 5 a shows a pre-drilling guide socket.
[0019] FIG. 5 b shows a drilling depth adjustment socket.
DETAILED DESCRIPTION
[0020] FIG. 1 shows one exemplary implant according to the present invention, in this case for use in the repair of a damaged condylar surface of the human femur. It is contemplated that in certain applications of the invention the outer surface of cap 3 of the implant 1 will be shaped to conform to the undamaged shape of the patient's condyle. Standard sized and shaped implants will also be covered by the scope of the main claim. Such implants can also be used for many different joint surfaces in, for example, the joints of the hip, knee, toe and shoulder.
[0021] The implant 1 has a cap 3 with on its outside 41 a new joint surface and on its inside, in this particular embodiment, a ridge 47 which lodge in a drilled groove as will be explained below. The implant cap has the shape of two intersecting circles of the same diameter. Typical implants according to the invention may have a cap with two intersecting circles of diameter 15 mm. Other shapes which may be suitable are 17+17 mm, 20+20 mm and 25+25 mm. At the center of each circle there extends a peg 48 , 49 . Each peg has, in this particular embodiment, a narrower end 48 a, 49 a to aid in directing the pegs correctly into drilled holes in the condyle, as will be explained in more detail below.
[0022] In this case, the first peg 48 is longer than the second peg 49 , but they can also be of the same length. According to the invention, both pegs are of the same nominal diameter, but the first peg 48 is slightly larger than the nominal diameter, providing an interference fit shaft of said nominal diameter. An anchoring interference fit between hard metal and living bone requires a greater differential than an interference fit between two metal elements. How much larger than the nominal diameter the first peg is will be a matter of clinical testing and revision. In this context involving a metal shaft in a hole in living bone and in the appended claims the term interference fit in relation to a nominal hole diameter is deemed to include positive differences up to and including approximately +11% increase in diameter over the nominal diameter. To get a very secure grip between a hole of a diameter of 4 mm in living bone and a peg of one of the materials described in the paragraph above, the peg should have a diameter of between ca 4.1 and 4.4 mm. An interference fit between hard metal and living bone requires a significantly larger difference than between a shaft and a hole of hard metal for example. The differential between the first peg diameter and the hole should not be so great as to require excessive force to put it in place with the risk of cracking in the bone. The second peg 49 has a diameter of the same nominal diameter but falling within the standard definitional boundaries for a clearance fit, i.e. almost of the same diameter but very slightly smaller. This relationship will ensure that the implant is securely anchored, is fairly easy to install, and will not give rise to problematic stresses between the pegs, either during implantation or thereafter.
[0023] FIG. 2 shows an example of a rig according to the present invention which is used for all of the hole preparation. The rig comprises an elongated hollow shell 51 having the form of two intersecting (overlapping) right circular cylinders 52 , 53 of the same diameter. The rig can be formed to conform to the shape of the bone and cartilage area of the patient to be repaired or can be a standard rig. The rig is held securely in place on the condylar surface in this case by pins (not shown) driven in through holes 61 , to hold the rig securely in place throughout the entire drilling process.
[0024] After the pins have been driven in, the cutting and drilling process can begin, with a wall insert 55 inserted in one end of the hollow shell, leaving an entire first right circular cylinder 52 at one end of the hollow tubular shell. At this time the surgeon may insert into the first right circular cylinder a depth adjustment socket 505 ( FIG. 5 b ) and then a sharp cylindrical hand knife, sized exactly to the interior of the adjustment socket 505 , make a preliminary circular sharp edged cut through the cartilage down to the bone. A circular bare bone area is left after this cartilage removal.
[0025] In one embodiment, the surgeon uses a 17/4 mm double drill as shown schematically in FIG. 4 . It has a central narrow 4 mm diameter bit 401 , and a wider 17 mm diameter cutting bit 402 . The outer lateral surface 403 of the double drill conforms to a height adjustment socket placed inside the wall insert, which securely holds the double drill to drill, in the same operation, a central 4 mm hole for the first peg 48 and a much shallower surrounding bore 17 mm in diameter in this example. A pre-drilling of the initial part of the peg hole in the bone can be made using a guide socket 501 ( FIG. 5 a ). This improves the exact placement of the simultaneous drilling of the peg hole and the circular bare-bone area with the double drill ( FIG. 3 ). After removing the drill, and flushing out organic matter, the surgeon then slides the wall insert 53 out and inserts it in on the other side of the hollow shell, creating a complete right circular cylindrical guide hole on the opposite side of the hollow shell.
[0026] The surgeon then inserts the adjustment socket and uses the same cylindrical knife in the newly created guide hole, to make a circular excision of the cartilage (not a complete circle since the intersecting portion has already been removed in the previous step). The in this embodiment 17/4 mm double drill is then used again first with the guide socket 501 to pre-drill the peg hole and then with the adjustment socket 505 to double-drill the peg hole to its full depth and create the bare-bone circle , i.e. the 4 mm hole for the second peg and a second surrounding shallow bore which is of course also 17 mm in diameter.
[0027] These two drilling operations have created 4 mm peg holes and a space in the bone to exactly accommodate in this case a 17+17 implant of the invention. The wall insert 53 is then completely removed. A handle-equipped gauge corresponding to the intersecting circular forms making up the implant, is used to make sure that the holes have been drilled to the proper depth in the bone. The rig is then removed and the implant pegs are inserted into their holes. For the cap of the implant to lodge exactly in the in this case 17+17 shallow cavity removed from the surface of the bone it is usually necessary to carefully tap the cap, preferably on top of the first peg, with interference fit, with a hammer via a special mandrel. The first, slightly thicker peg, is tapped down into its hole while the second peg, slightly narrower, slides easily into its hole. The larger diameter part of the 17/4 mm drill in this example has a rim to excavate a peripheral slot slightly deeper than the 17 mm shallow cavity, to accommodate the peripheral ridge 47 of the implant, helping to hold the implant securely in place during healing and subsequent loading during use.
[0028] Thus the rig, which can be form-fitted to the shape of the individual patient's condyle in this example, is placed over the damaged area of the condyle and is anchored securely in place, in this particular non-limiting example, by driving in four pins (not shown) into holes 61 in the condyle shaped lower end of the rig 50 . It is now securely in place for the entire drilling operation, which be simplified greatly and made much more exact and less dependent on the artistry of the surgeon, which may vary from day to day.
[0029] After drilling of the holes, the pins are pulled out and the rig is removed from the site, for implantation of the implant and reconstitution of the joint with the new implant.
[0030] It will be understood by the person skilled in the art that the rig as claimed can be supplemented with for example an insert sleeve to make one of the right circular cylinders of a small diameter, e.g. from 17 to 15 mm in diameter, to accommodate an implant having the form of two intersecting circles of slightly different diameters, for example 15+17 millimeters.
[0031] It will of course also be possible, within the scope of the invention to create an implant in the form of three, or more, intersecting circles, to cover bone damage of more irregular shape.
[0032] One such three-circle implant 101 is shown from below in FIG. 3 a showing three pegs 148 , 149 and 150 . In this example peg 148 has an interference fit diameter in relation to the common nominal diameter of all three pegs and the other two pegs 149 and 150 have clearance fit diameters in relation to the common nominal diameter.
[0033] The rig for this three-circle implant is shown from above in FIG. 3 b . The rig is held in place on the bone by pins (not shown) inserted through holes 161 . The wall insert 155 , completes the first right circular cylinder 152 covering the remaining portions of the other two right circular cylinders. When the first circular drilling has been made the wall insert 155 is pulled out, rotated 120 degrees and is inserted again to provide a drill guide for the next circle drilling with the same double drill, which in one embodiment can be the same 17/4 drill used together with the two-circle rig. After rotation 120 degrees again and drilling, a three pegged implant is inserted. As stated above, this insert has one peg which is of interference fit dimension in relation to its nominal diameter (in this case 4 mm) and the other two pegs are of clearance fit.
[0034] The implant has a bone contact surface on the underside, on the sides of the cap and on the pegs, which will be in direct contact with the bone tissue when the implant is in place. In one embodiment the bone contact surface comprises a biocompatible metal, metal alloy or ceramic, such as any of the metals, metal alloys or ceramic described above for the articulate surface. Preferably the bone contact surface comprises a cobalt chrome alloy (CoCr), a titanium alloy, titanium or stainless steel.
[0035] In one specific non-limiting embodiment the bone contact surface comprises, or in one specific non-limiting embodiment is coated with, a material that promotes osseointegration. In an alternative embodiment of the invention the bone contact surface does not comprise such a material and/or is uncoated.
[0036] The bioactive material or the material that promotes osseointegration of the bone contact surface, if present, preferably stimulates bone to grow into or onto the implant surface. Several materials that have a stimulating effect on bone growth are known and have been used to promote adherence between implants and bone. Examples of such prior art materials include bioactive glass, bioactive ceramics and biomolecules such as collagens, fibronectin, osteonectin and various growth factors. A commonly used material in the field of implant technology is hydroxyapatite (HA), chemical formula Ca 10 (PO 4 ) 6 (OH) 2 . HA is the major mineral constituent of bone and is able to slowly bond with bone in vivo. HA coatings have been developed for medical implants to promote bone attachment. Another bioactive material commonly used in prior art is bioactive glass. Bioactive glasses, generally comprising SiO 2 , CaSiO 3 , P 2 O 5 , Na 2 O and/or CaO and possibly other metal oxides or fluorides, are able to stimulate bone growth faster than HA.
[0037] The fixation of the implant can also be improved by decreasing the catabolic processes i.e. decrease the amount of bone resorption next to the implant. The bone contact surface and/or the extending post can also be modified with bisphosphonates.
[0038] In one embodiment the bone contact surface is coated with a double coating. Such double coating may for instance comprise an inner coating comprising titanium (Ti). The second, outer coating, that is configured to contact the cartilage and or bone, is preferably a hydroxyapatite and/or beta tricalcium phosphate (TCP) coating. By this design even more long-term fixation of the implant is achieved, since bone in- or on-growth to the implant is further stimulated by the titanium, even if the more brittle hyroxyapatite would eventually shed/dissolve.
[0039] The bone contact surface may also be further modified with fluoro compounds or acid etching to enhance the bioactivity and the osseointegration of the surface. Another method to facilitate osseointegration is blasting of the bone contact surface.
[0040] FIG. 4 shows an exemplary 4/17 double drill for use with the multiple circle rigs described above (or with a previously known single circle rig). The double drill has a 4 mm central bit 401 for creating the hole for the peg and a wider cutting surface 402 for creating the 17 mm shallow hole. One of the advantages of the invention is that the same double drill can be used for single, double or triple (or more) intersecting circle shaped implants, used twice or three times as the case may be for the two embodiments shown here.
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A surgical joint implant has a cap in the form of at least two intersecting circles of the same diameter having an articular outer surface and an inner surface for bone adhesion. At the center of each circle a peg, for bone insertion into a hole of a nominal diameter, extends. One peg is slightly larger than said nominal diameter, to achieve an interference fit and the other peg is slightly thinner, to achieve a slide fit. A tubular drill rig open at both ends and having an interior circumference corresponding to the outer shape of the implant, can be mounted over the bone surface to be repaired. It accommodates a double drill for drilling, at the same time, a shallow hole of the diameter of the intersecting circle and a deeper narrow hole at the center of the circle of said nominal diameter.
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BACKGROUND AND SUMMARY OF THE INVENTION
The conventional dynamic engines mainly include the reciprocating engine, the rotary engine and the turbine engine. The reciprocating engine possesses a very large volume, a complicated structure and a thermal efficiency under 28%. The representative rotary engine is the Wankel engine. The eccentricity of its eccentric shaft is too small, the moment of force which it provides is too small also, and its thermal efficiency is only about 26%. The rotating speed of the compressive vane of a turbine engine must reach 30,000 rpm before it can produce an effective compressive ratio, and the compressive vane directly accepts the counter force of expansion gas in the combustion chamber therefor. Its thermal efficiency is only about 30%. The reason why the thermal efficiency of each of these engines is low is discussed hereafter.
In operation, each of these kinds of engines will produce high levels of heat which affects the normal operation. The heat can be reduced by a cooling method, but the heat absorbed in the cooling method can directly cause a cooling loss of the engine, and this cooling loss will be up to 30%. Furthermore, waste gas exhausted from the engine still possesses very high heat energy, but this high heat energy can exhaust continuously during operation of the engine, and thus will cause a very large loss of heat energy called an exhaust loss. According to experiment, the exhaust loss of every kind of engine is about 32%. The so-called mechanical loss of a turbine engine is due to its compressive vane being of an open type design, the combustion chamber being connected with the outside through the space of the compressive vane, and the requirement that the compressive vane must possess a rotating speed of at least 30,000 rpm in order to produce an effective compressive ratio. The compressive vane directly accepts the counter force of expansion gas in the combustion chamber and exhausts the large quantity of output dynamics from the dynamic vane. This mechanical loss is about 50% and is the largest loss in every kind of engine.
Recognizing the above drawbacks, the purpose of the present invention is to provide a design of a highly efficient rotary engine structure, whose concept of design is to possess the merits of each of the above-noted engines, and to improve on the various drawbacks thereof in structure, in a rotary type engine possessing a small volume, a light weight, and having moving parts which perform pure circumferential motion so that their mechanical effectiveness is high. In the invention, energy is to be converted in the brief steps of compression, combustion, and expansion of the turbine engine.
The mode of performance of the engine is to use an inner water spray cooling method. After absorbing high levels of heat during combustion, cooling water will convert the heat into useful high pressure steam. This method can avoid cooling loss, and completely mix the steam with fuel to be misted prior to combustion and thereby cause the mixed gas to completely burn.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of the combination of the present invention.
FIG. 2 is a cross-sectional view of the compressive rotor and compressive cylinder of the present invention.
FIG. 3 is a cross-sectional view of the dynamic rotor and the cylinder of the dynamic rotor of the present invention.
FIG. 4 is a cross-sectional view of the water flow controller.
FIG. 5A is a cross-sectional view of a one-way driving device of the present invention.
FIG. 5B is a partial cross-sectional view of the driving device of FIG. 5A taken along the line 1--1.
FIGS. 6-9 are figures similar to FIG. 3 at different stages of operation and illustrating a torque analysis of the present invention.
FIG. 10 is a comparison of view of in cross section of the gas chamber pressure in the dynamic rotor cylinder of the present invention.
FIG. 11A is an exploded view of the dynamic valve plate sealing device of the present invention.
FIG. 11B is a cross-sectional view of the device of FIG. 11A taken along line 2--2.
FIG. 12 is a cross-sectional view of the dynamic rotor sealing device of the present invention.
FIGS. 13 and 14 are partial cross-sectional views of the sealing body in the dynamic rotor illustrating its function.
FIG. 15 is a partial schematic view of the lubrication oil passage of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The structure of the present invention mainly includes a compressive mechanism, a combustion mechanism and a dynamic transmission mechanism which are described as follows:
COMPRESSIVE MECHANISM
FIG. 1 is a cross-sectional view of the overall combination of the present invention. The compressive mechanism of the present invention includes compressor 1, compressive rotor 2, dynamic rotor 3, fuel pump 4 and water pump 5. Compressive rotor 2 is of a pure cylindrical type. Rotor 2 is provided eccentrically on a hollow shaft 21 mounted on a long shaft 32. At the outer circumferential surface of compressive rotor 2, there is assembled an outer ring 20, and between outer circumferential surfaces of outer ring 20 and compressive rotor 2, there is provided a ring of rigid rolling pins 201 which is used as a rolling contact interface. At each of the two end faces of outer ring 20, there is provided a sealing ring 202 which is used as a sealing device.
Dynamic rotor 3 is also of a pure cylindrical type and is eccentricly integrally formed on adjacent ends of long shaft 32 and a short shaft 31 colinear with long shaft 32, both of the two shafts being hollow and communicating with the inner part of rotor 3. Two unconnected passages separated by an inclined partition are formed in the shafts, one being an intake passage 311 in shaft 31 and the other being an exhaust passage 321 in shaft 32. In the exhaust passage 321, there is provided a heat-insolating porcelain pipe 322 which is used for isolating heat.
The compressive rotor 2 is sleeved by hollow eccentric shaft 321 over the long shaft 32 of dynamic rotor 3. Compressive rotor 2 and dynamic rotor 3 are sealed by side covers a, b, and c, wherein side covers a and c are respectively formed of a flange and a bearing. In the flanges of covers a and c, there are respectively assembled a main bearing A and a main bearing C to support the short shaft 32 of dynamic rotor 3 and shaft 21 of compressive rotor 2, whereby compressive rotor 2 and dynamic rotor 3 can respectively and smoothly make eccentric rotation in the compressive cylinder 22 and dynamic rotor cylinder 33.
On the free end of shaft 21 of compressive rotor 2, there is assembled a starting geared disk 23. On the geared disk 23, there is attached a belt pulley 231, 232 which is connected with air compressor 1, fuel pump 4 and water pump 5 by the belt 232 and rotated together. Starting geared disk 23 is used for starting and is driven by gear 121 of starting motor 12. In the starting geared disk 23, there is formed a weighted concavity 233 which is used for balancing the weight of compressive rotor 2. At the free end of long shaft 32, there is provided a dynamic rotor flywheel 34 in which there is provided a driving gear 341 to engage with a gear 61 on a dynamic output shaft 6, and to transmit dynamics (rotational energy) produced by dynamic rotor 3. Between the starting geared disk 23 and the dynamic rotor flywheel 34, there is provided a one-way driving mechanism, and in the dynamic rotor flywheel 34, there is formed a weighted concavity 342 for balancing the weight of dynamic rotor 3.
Compressive rotor 2 makes eccentric rotation in compressive cylinder 22 in order to compress air, as shown in FIG. 2, on the wall of the cylinder. A pivot 220 is used to pivotally connect a compressive valve plate 221 to cylinder 22 and provide compressive cylinder 22 into two unconnected gas chambers 222 and 223. Compressive valve plate 221 can be centered by pivot 220 to swing and transfer properly.
The space surrounding the outer cylindrical surface of compressive cylinder 22, inside the eccentrically surrounding outer cylinder wall of cylinder 22 is divided into several connected gas containing chambers 224. A one-way valve 225 is provided through cylinder 22 into the small volume chamber 224, and high pressure gas, after being compressed, can be stored in gas containing chambers 224 through gas chamber 222, but cannot flow in reverse into gas chamber 222. In the outer ring circumferential wall of compressive cylinder 22, there is provided a guide pipe 226 to transmit high pressure air from gas containing chamber 224 into compressor 1 for secondary compression. The above-mentioned compressive valve plate 21 closely contacts the outer ring 20 on the outer circumferential surface of compressive rotor 2. Since at the outer circumferential surface between outer ring 20 and compressive rotor 2, there are provided the rigid rolling columns 201 which are used as a friction interface, the rotating speed of outer ring 20 is less than that of the compressive rotor, thereby reducing frictional energy loss caused by friction between outer ring 20 and compressive valve plate 221.
Dynamic rotor 3 is surrounded by several dynamic valve plates 331 pivotally mounted at certain intervals along the inner circumferential wall of dynamic rotor 33, as shown in FIG. 3. The dynamic valve plates 331 are pivotally mounted on the circumferential wall by pivots 330, and each dynamic valve plate 331 can be centered by a pivot 330 to swing and transfer properly. Through the placement of each dynamic valve plate 331, the circumferential volume between dynamic rotor 3 and dynamic rotor cylinder 33 is divided into several unconnected gas chambers 331. Since dynamic rotor 3 makes eccentric rotation in the dynamic rotor cylinder 33, the volume of the gas chambers 332 at the circumference of dynamic rotor 3 near the top of rotor 3 (its most eccentric part) is smaller than the volume of the gas chamber 332 at other parts. Thus, when dynamic rotor 3 starts to make eccentric rotation, the volume of each gas chamber alternately increases and decreases as the rotor 3 rotates. Referring to FIGS. 3, 13, and 14, the dynamic rotor cylinder 33 has radially inwardly projecting partition parts 333 adjacent the pivots 330. Each partition part 333 has a setting groove 334 through inclined hole 337. The compressive spring 336 acts on the sealing body 335 so that the sealing body is resiliently movable a small distance further into the setting groove 334. Communication between the radially outward end of setting grooves 334 and gas chambers 332 is provided by inclined holes 337 in parts 333 which let high pressure gas enter into the setting groove 334 through inclined hole 337.
Combustion Mechanism
The combustion mechanism of the present invention includes an internal pressure vessel (can) 7, external pressure vessel (can) 8, water nozzle 81, fuel nozzle 82 and plug 83. As shown in FIG. 1, internal pressure can 7 is placed inside the external pressure can 8, space formed in can 8 constituting a steam generating chamber 71. The space inside internal pressure can 7 comprises a combustion chamber 72. The open end portion (left side portion in FIG. 1) of said can 7 extends through shaft 31 into intake passage 311 of dynamic rotor 3, thereby providing communication between combustion chamber 72 and intake passage 311.
External pressure can 8 closely joins with side a. The water nozzle 81 and a water flow controller 51 (as shown in FIG. 4) are mounted on the can 8. A source of water to the water nozzle 81 is provided by a guide pipe 52 connected to water flow controller 51 from water pump 5, and a guide pipe 511 connecting controller 51 to water nozzle 81. Compressor 1 is connected by a guide pipe 11 to water nozzle 81 to guide high pressure gas to water nozzle 81 when water is injected from water nozzle 81 into steam generating chamber 71. High pressure air is also injected into chamber 71, whereby the water enters chamber 71 as a mist. When the mist contacts the high temperature internal pressure can 7 and then becomes a high pressure steam, part of the steam enters the combustion chamber 72 through front osmosis hole 73, peripheral osmosis hole 74 and rear osmosis hole 75 of pressure can 7.
Another part of the steam enters into fuel mixing chamber 822 through penetrated hole 821 of fuel nozzle 82 and mixes with injected fuel to become mixed gas, and then is injected through nozzle 82 to combustion chamber 72 where the mixture is ignited by plug 83. The fuel nozzle 82 penetrates external pressure can 81 and extends into internal pressure can 7, and is connected to a fuel controller 84 which controls the feed of fuel. Fuel is fed and pumped through controller 84 into nozzle 82 by fuel pump 4. Water nozzle 81 has connected thereto a snifting valve 85 which is set to open when the pressure in nozzle 81 is over a preset safety pressure value and release pressure in order to ensure safe operations.
The assembly of water flow controller 51 of the present invention, as shown in FIG. 4, includes an aluminum bar 512 screwed into a copper pipe 513 by screw nut 514 at the open end of pipe 513. The screw nut 514 permits adjustment of the bar 512.
The coefficient of expansion of aluminum bar 512 is 23.8 which is larger than the coefficient of expansion of copper pipe 513 which is 14.1. Therefore, when the fuel starts to ignite and the engines starts to operate, and copper pipe 513 begins to absorb heat, aluminum bar 512 will also indirectly absorb heat from copper pipe 513, but since the coefficient of expansion of aluminum bar 512 is larger, it expands in copper pipe 513 axially away from screw nut 514 until the concave hole 515 in the aluminum bar 512 is aligned with guide pipe 511 thereabove and a passage 516 therebelow. With such alignment, groove 515 becomes a flow passage for water, and water pumped out by water pump 5 can flow therethrough to water nozzle 81.
The temperature at which expansion of aluminum bar 512 aligns the concave hole 515 with the passage 516, can be adjusted and set as requirements demand. Usually, aluminum bar 512 starts to expand and extend when external pressure can 8 reaches 200° C. When it does not reach said temperature, water pumped by water pump 5 will flow back into water pump 5 through a one-way valve 517 because passage 516 is not open. The concave hole 515 of aluminum bar 512 moves to gradually open passage 516 as the temperature of the external pressure can increases and thus the bar 512 serves to control the adjustment of the water supply.
Dynamic Transmission Mechanism
The dynamic transmission mechanism of the present invention includes starting geared disk 23, dynamic rotor fly wheel 34 and dynamic output shaft 6. As mentioned above, starting geared disk 23 is used to start the engine. When commensing to start the engine, starting geared disk 23 is driven by the starting motor to drive compressor 1 to compress air, and let dynamic rotor 3 start to perform work to transmit rotative energy. However, between the starting geared disk 23 and dynamic rotor fly wheel 34 at the free end of long shaft 32 of dynamic rotor 3, there is provided a one-way driving device. Therefore, before the dynamic rotor 3 starts to transmit rotative energy, the compressive rotor 2 is in a static condition. Until the dynamic rotor 3 starts to rotate and transmit rotative energy, the starting geared disk 23 will operate continuously through the one-way driving device, and the rotative energy transmitted from dynamic rotor 3 will be transmitted out to dynamic output shaft 6 through dynamic rotor flywheel 34. After starting geared disk 23 is driven by dynamic rotor flywheel 34, the starting motor will seperate from the starting geared disk 23 and stop driving.
The one-way driving device is shown in FIG. 5, wherein at one end of starting geared disk 23 corresponding to dynamic rotor flywheel 34, there is provided a concave toothed hole 23, and at one end of dynamic rotor flywheel 34, pivots 35 pivotally fix several pins 36 in a same rotational direction. The pins 36 can rotate in one direction and engage with toothed hole 24 of starting geared disk 23. When starting geared disk 23 drives compressor 1 and compressive rotor 2 and rotates in the designed direction (as shown by the arrows in FIG. 5B), dynamic rotor fly wheel 34 will not be driven because pin 36 rotates in one direction. Therefore, dynamic rotor flywheel 34 is also static. When dynamic rotor 3 starts to operate and drive co-axial dynamic rotor flywheel 34 to rotate along the designed direction (as shown by the dotted line arrow in FIG. 5B), pins 36 engage toothed hole 24 of starting geared disk 23 and let starting geared disk 23 be driven to operate, and the starting geared disk 23 is further linked with compressor 1 to operate continuously (it substitutes for starting motor 12) and compresses air continuously, and rotative energy produced by dynamic rotor 3 is transmitted out through dynamic output shaft 6.
The description of the structure of the present invention being as described above, the operation of the invention is described as follows:
Starting
The starting of the present engine is initiated by closing the battery circuit to starting motor 12 and plug 23. Then starting motor will begin to drive starting geared disk 23, and plug 83 will continuously discharge to ignite the fuel gas mixture. When starting geared disk 23 starts and operates, it also drives air compressor 1 simultaneously, and fuel pump 4 and water pump 5 respectively begin to pump fuel and water to fuel nozzle 82 and water nozzle 81, respectively. Compressive rotor 2 continuously draws fresh air from outside of the engine into gas chamber 223 through absorptive hole 227, and after being compressed by compressive valve plate 221, it is stored in the gas containing chamber 224. After gas containing chamber 224 is full of high pressure air, high pressure air will enter air compressor 1 through guide pipe 226 and be compressed therein still further. High pressure air from compressor 1 is then guided by guide pipe 11 to fuel nozzle 81 and enters steam generating chamber 71. As mentioned above, when starting geared disk 23 starts, it simultaneously drives pump 4 to pump fuel to fuel controller 84 which adjusts and controls the amount of fuel which enters fuel mixing chamber 822. At that time, part of the high pressure air injected into steam generating chamber 71 will enter combustion chamber 72 for cooling through osmosis holes 73, 74 and 75. However, most of the air will enter fuel mixing chamber 822 through penetrated hole 821 and mix with the injected fuel to form a high pressure gas/fuel mixture which is injected into combustion chamber 72 where it is ignited by plug 83 to produce high pressure igniting and combustion gas which immediately enters intake passage 311 of dynamic rotor 3 from the end of combustion chamber 72, and flows into the smallest of the gas chambers 332 where it applies to the circumferential surface of dynamic rotor 3 a rotation force thereby to cause dynamic rotor 3 to rotate forward and perform work (see FIG. 10). Rotation of dynamic rotor 3 drives dynamic rotor flywheel 34 to transmit rotational energy out through dynamic output shaft 1, and thereby substitutes for starting motor 12 through linking with the one-way driving device and drives the compressor 1 to operate continuously. Therefore, the whole engine will be operating.
While the engine is being started, water pump 5 begins to pump water continuously to water flow controller 51, but due to the water flow passage 516 of water flow controller 51 not being opened, all the water flows back to water pump 5 through one-way valve 517. After the engine has rotated for a period of time, its temperature will gradually rise to a designed temperature (200° C.), the aluminum bar 512 will begin to expand and extend after being heated, concavity 515 will become aligned with passage 516, and water pumped by water pump 5 will flow to water nozzle 81 and be ejected therefrom into steam generating chamber 71. Water mist ejected from water nozzle 81 mixes with high pressure air compressed by air compressor 1, at water nozzle 81 and enters steam generating chamber 71, cools internal pressure can 7, and develops a large volume of steam. The main air current of the large volume of steam passes through hole 821 of fuel nozzle 82 and enters fuel mixing chamber 822 where it mixes with fuel to become a fuel/gas mixture and is then injected into combustion chamber 72 and is ignited by plug 83.
The second air current is separated into three streams. The first stream enters combustion chamber 72 through front osmosis holes 73 and forms a surrounding convection current so as to protect the internal pressure can 7 by isolation of the walls of the can from the heat, and to aid further burning of the combustion gas to reach complete combustion and thereby promote thermal efficiency and cleaner exhaust. The second stream enters combustion chamber 72 through peripheral osmosis holes 74 and protects the rear part of internal pressure can 7. The second stream also lowers the temperature of combustion gas below 1,000° C. The third stream infiltrates bearings A through rear osmosis hole 75 to cool the bearings A and further lower the temperature of combustion gas entering dynamic rotor 3 to about 500° C.
The side surface of internal pressure can 7 is protected by the infiltrated steam while the outside is cooled by the fluid in steam generating chamber 71. Therefore, steam generating chamber 71 can accept combustion at a very high temperature, and limit combustion gas to the core (central) part. Moreover, the can 7 receives a low external temperature and can therefore maintain its strength and accept stronger combustion pressure from within.
Loading Operation
After starting, the engine will function normally, and also there is enough air being continuously transmitted into combustion chamber 72. If the user now depresses the accelerator, the engine will operate rapidly. The operation of pumping oil is the same as in a reciprocating engine. If the user actuates the clutch, the action of filling oil will be started, and the engine will be in the loading operation stage.
Stop Operation
When the engine is stopped, firstly, it must decelerate (reduce oil). The clutch is disengaged simultaneously, and the engine rotates without performing work. The engine will be stopped after the fuel is completely cut off.
The principle of operation and other structural characteristics of the present invention will be described as follows:
Analysis of Torque, Eccentricity and Applied Force, and Dynamic Overlap
Referring to FIGS. 6-9, the pressure of expansive gas in the small gas chamber 332 will press on the surfaces A, B of dynamic rotor 3. The resultant force Pg is directed toward the center of rotor 3. The force at the center may be divided into two components Pb and Ft1. Force Pb is directed radially toward the center point of the rotating shaft 31 and constitutes a useless force loaded on the bearing. Force Ft1 is directed tangent to the rotating shaft and thus rotates the shaft. The distance from the mandrel of the eccentric axle of rotor 3 to the center of dynamic rotor cylinder 33 is the arm of force e of the rotating shaft (the eccentricity of the rotating shaft). Therefor, the moment of the engine Md=Ft1×e. If the effective tangential forces of other gas chambers are respectively Ft2, Ft3 and Ft4, then the effective torsion of the present engine Ft=Ft1+Ft2+Ft3+Ft4, of the total torsion is given by Md=Ft×e. Therefore, it can be seen that under a same gas pressure the main factors affecting the efficiency of the engine are the arm of force e and the working direction of the gas.
The procedure of compression, combustion and expansion of the present engine is based on the turbine engine method. The engine has a closed passage system and performs continuous equi-pressure combustion. When high pressure gas in combustion chamber 72 passes through intake passage 311 and is successively distributed into the then small gas chamber 332, the corresponding dynamic valve plate 331 will seal and isolate the small gas chamber 332 from the outside because of the application of pressure on dynamic valve plates 331. When the small gas chamber 332 and combustion chamber 72 are connected, high pressure gas in combustion chamber 72 continuously flows into the connected small gas chamber 332. Therefore, pressure in small gas chamber 332 becomes the same as the pressure in combustion chamber 72, and both of these pressures are the highest pressures. Therefore, the effectiveness of the present invention is superior to that of a conventional engine.
Sealing Device
Dynamic valve plate 331 and compressive valve plate 221 respectively contact dynamic rotor 3 and compressive rotor 2, and at the respective contact parts, there is no sealing device. As to the sealing valve 331, during expansion of the gas in gas chambers 332, the volume of each gas-filled gas chamber expands and thus pressure in the small gas chamber is larger than the pressure in the next larger gas chamber and so on, as illustrated in FIG. 10. Therefore, the valve plates 331 are pivotally pressed against dynamic rotors by the differential pressure in adjacent gas chambers 332 and thus the contact sealing function performed by dynamic valve plates 331 and dynamic rotor 3 is good and precise. For ensuring the pneumatic sealing effect between each separated gas chamber, the pneumatic sealing of gas chambers 332 can be obtained by providing at two sides of each valve plate 331 and at the end surface at two sides of dynamic rotor 3, a sealing ring. See FIGS. 11A, 11B and 12. In FIGS. 11A and 11B, at the two sides of dynamic plate 331, there are respectively provided an arc groove 331-1. In each groove, there is placed a compressive spring 331-2 and a valve side sealing body 331-3. On the surface of dynamic valve plate 331, there is provided a gas hole 331-4. Gas hole 331-4 is connected to a gas hole passage 331-5 which extends transversely through valve plate 331 and is connected at opposite ends with the respective grooves 331-1. Therefore, some high pressure gas in the small gas chamber 332 will flow from gas hole 331-4, through gas hole passage 331-5 and enter into groove 331-1, and push outwardly against sealing bodies 331-4 so that the latter move outwardly and closely seal against the side covers a and b to thereby provide an effective pneumatic seal.
In accordance with the same principle, at the two side surfaces of dynamic rotor 3, there are also provided respective ring shape grooves 39. In each groove 339 there is placed a ring type wave plate spring 391 and a sealing ring 392, and at the bottom of each groove 39, there is provided a gas hole 393 which is connected to intake passage 311 of dynamic rotor 3. Gas holes 393 can direct high pressure gas to press the sealing rings into a closely sealing relationship with the side covers a and b.
The sealing devices of compressive valve plate 221 are the same as those of dynamic valve plate 331. On the outer circumferential surface of compressive rotor 2, there is provided the outer ring 20, and on the two side end surfaces of the outer ring 20, there are provided respective sealing rings 202 which are used as sealing devices which function in the same manner as the sealing rings 352 at the two side end surfaces of dynamic rotor 3, in order to provide an effective pneumatic seal.
Thd dynamic rotor cylinder 33 of the present invention possesses respective partition parts 333 adjacent to the pivots 330 of dynamic valve plate 331. Each partition plate 333 has a setting groove 334 in which a sealing body 335 is provided. When dynamic rotor 3 eccentrically rotates in dynamic rotor cylinder 33, the most eccentric point of the dynamic rotor 3 rotates to the location between the two gas chambers 332 where the sealing body 335 is provided (as shown in FIG. 13). At this time, one gas chamber 332 is connected with intake passage 311 of dynamic rotor 3 for gas intake and another (adjacent) gas chamber 332 connects with exhaust passage 321 of dynamic rotor 3 for gas exhaust.
Therefore, at this point, pressures in the two neighboring gas chambers 332 differ widely. In order to prevent leakage of high pressure gas from the higher pressure gas chamber 332 to the neighboring lower pressure gas chamber 332 which would cause exhaust loss, there is provided the above-mentioned sealing body 335 in dynamic rotor cylindner 33. Usually, sealing body 335 is pushed by the tension of compressive spring 336 and extends into dynamic cylinder 33. When the highest point of dynamic rotor 3 moves to the position of partition part 333, sealing body 335 is pushed by dynamic rotor 3 back into the setting groove 334, but due to the tension of compressive spring 336, it closely contacts the outer circumferential surface of dynamic rotor 3. Then, a small portion of the high pressure gas in the higher pressure gas chamber 332 enters the setting groove 334 from inclined hole 337 in order to increase the force on the sealing body 335 against rotor 3 and thusly, the sealing body 335 is completely sealed against the dynamic rotor 3, and can effectively prevent high pressure gas from leaking from the higher to the lower pressure gas chamber 332 as illustrated in FIG. 14. The bottom end face of the above sealing body 335, which contacts dynamic rotor 3, can be provided with an arc corresponding to the outer circumferential surface of the dynamic rotor 3 in order to further improve the seal between dynamic rotor 3 and sealing body 335.
Lubrication System
The lubrication system of the present invention uses the method of compulsory lubrication. The lubrication system of the present invention as illustrated in FIG. 15, possesses an axial lubrication return passage and a radial type lubrication passage which are described as follows:
Axial Lubrication Return Passage
At the bottom of oil tank 9, there is provided an oil pump 91 driven by an inclined gear 62 of dynamic output shaft 6. At the outside of main bearing A, there is a gas seal A1 and an oil seal A2, and at the outside of main bearing C, there is provided an oil seal C1. Oil is pumped out by oil pump 91, and is firstly cooled by a cooler (not shown) and then flows through a filter (not shown) to be filtered and then split and transmitted into main bearings A and B to lubricate main bearings A and B. Lubricant through main bearing A will immediately pass through space between short shaft 31 of dynamic rotor 3 and side cover a and enter into the right side of dynamic rotor 3 to provide lubrication thereto. Lubricant completely lubricates the sealed area at the right side of dynamic rotor 3 and then passes through the top of dynamic rotor 3 to connect through and enter into the left side of dynamic rotor 3 in order to provide lubrication thereto, and then enters the inside of shaft 21 of compulsory rotor 2 through space between side cover b and long shaft 32, in order to lubricate and cool the shaft 21 of compressive rotor 2 and finally flow back to oil tank 9. The lubrication oil passage of lubricant which goes through main bearing C is the same as the oil passage of the above main bearing A which lubricates two sides of compressive rotor 2 in a reverse direction, and meet with an oil passage of main bearing A. The lubricant flows back to the oil tank 9 through the inside of shaft 21 of compressive rotor 2.
Radial Lubrication Return Passage
When lubricant flows to the top face of dynamic rotor 3 and compressive rotor 2, part of the lubricant seeps out from a very small hole to lubricate the valve plate and circumference of the rotor. The lubrication of the pivot part 220 of compressive valve plate 221 can be performed by pumping a small quantity of lubricant.
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A rotary engine including a compressor, an external pressure vessel, an internal pressure vessel defining a combustion chamber, and a fuel nozzle opening into the combustion chamber. Both compressed air and fuel are pumped into the fuel nozzle. Water is sprayed into the compressed air prior to entering the nozzle. Compressed air and water are directed between the interior and exterior pressure vessels so that the water cools the walls of the interior vessel and is turned to compressed steam. A mixture of steam, compressed air and fuel is formed at the fuel nozzle and is directed into the combustion chamber where it is ignited by an ignitor to produce a high temperature high pressure gas. The high temperature high pressure gas is directed into a dynamic rotor cylinder where its pressure eccentrically rotates a dynamic rotor which is in turn coupled to an output shaft.
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BACKGROUND
This invention relates generally to devices which receive and transmit wireless signals.
A variety of devices may be involved in receiving and transmitting wireless signals. A variety of processor-based systems may communicate with one another in a wireless network over relatively short or longer range distances. In addition, devices such as cell phones that have been conventionally thought of as communication devices may also function as processor-based systems.
As a result, in a number of different instances, devices may be able to send and receive wireless signals from the same or closely proximate hardware operate under two or more different wireless protocols on the same processor-based system. In addition, devices may operate in two or more different wireless networks from the same processor-based system. Thus, each network or protocol may be generally unaware of communications in the other network or protocol.
As a result of the ability to send and receive signals at the same time from proximate devices, one device may fail to account for the other. One result may be interference between communications in the two different wireless devices.
Thus, there is a need for ways to control or reduce interference when proximate devices coupled to a common processor-based system, are able to transmit and receive wireless signals at the same time over different wireless networks.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a hardware schematic view of one embodiment of the present invention; and
FIG. 2 is a flow chart for software in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
Referring to FIG. 1 , a wireless device 10 may be a processor-based system or a communication device. Examples of processor-based systems include desktop, laptop, and portable processor-based systems, commonly known as computers. Examples of wireless communication devices include cellular telephones, wireless network interfaces, and access points for wireless networks.
In some embodiments, the wireless device 10 may be controlled by a single processor that controls both the wireless transmission and the general processing tasks. In other cases, one processor may be utilized for wireless communications and another processor may handle the execution of any of a wide variety of software applications.
In the embodiment shown in FIG. 1 , a separate digital signal processor 11 and general purpose processor 12 are illustrated. However, any type of controller may be used. The general purpose processor 12 may be responsible for executing various applications while the digital signal processor 11 may be responsible for handling wireless communications. In some cases additional processors may be provided. In other cases, one or more general purpose processors may be utilized. In some cases one or more digital signal processors may be utilized.
In one embodiment, the general purpose processor 12 may be coupled to a storage 14 that may store one or more applications, such as the application 16 . The storage 14 may take a wide variety of forms. In battery powered applications, the storage 14 may be, for example, a flash memory. In other cases, the storage 14 may be a hard drive. In general, the storage 14 may be any semiconductor memory, any disk-based memory, or, in general, any device capable of storing an application program.
The processors 11 and 12 may be coupled by a bus 18 to a pair of network interfaces 20 a and 20 b in one embodiment. Each network interface 20 a or 20 b may be coupled to a different wireless network in one embodiment. Currently, a variety of wireless protocols are in widespread use. For example, cellular telephones may use a variety of wireless protocols including time division, code division, and analog protocols, to mention a few examples. Also, personal computers and other devices may communicate over short-range wireless protocols, such as the Bluetooth protocol (See Bluetooth Specification v. 1.1 (2003)) or ultra-wide band, also known as digital pulse wireless, as well as longer range wireless protocols, such as the IEEE 802.11 protocol (See IEEE 802.11, 1999 Edition (ISO IEC 8802-11; 1999). In addition, various wireless networks may be set up, such as personal area networks (PANs). These wireless networks may use the same or different wireless protocols, and they may be managed independently of one another.
For example, one wireless network may operate at 5 gigahertz according to an 802.11a protocol and another wireless network may operate at from 3.1 to 10.6 gigahertz at low power according to an ultra-wide band protocol. Thus, the operating frequencies of the two protocols overlap, making interference likely if a system attempts to transmit on one protocol and to simultaneously receive on the other protocol.
As a result, in one embodiment, for one or a variety of reasons, the wireless interfaces 20 a and 20 b may be coupled to the networks that are relatively independent of one another. The problem that arises is that one of the interfaces, such as the interface 20 a , may attempt to transmit while the other interface 20 b is attempting to receive. In many cases, the simultaneous proximate transmission and reception would result in interference absent coordination between the interfaces 20 .
Within any given wireless network there may be protocols for reducing interference. These protocols may prohibit one wireless entity from transmitting while other wireless entities within the network, including the transmitting entity, are attempting to receive. However, where a single device 10 is capable of participating in disparate, uncoordinated, networks, such coordination may not be available because each network may operate independently of other networks.
Using the application 16 , the general purpose processor 12 may control the wireless interfaces 20 to avoid at least in some cases, transmitting over one interface, such as the interface 20 a , when the interface 20 b is attempting to receive, in one embodiment. To this end, the processors 11 and 12 may communicate with one another.
The connection between the bus 18 and each interface 20 a or 20 b may be a wired or wireless connection. In addition, the interfaces 20 a and 20 b may be proximate or remote from the processors 11 and 12 .
Each network interface 20 a and 20 b may include an antenna 22 a or 22 b that, in one embodiment of the present invention, may be a dipole antenna. In one embodiment, the antennas 22 may be responsible for both transmission and reception of signals. More or less antennas may be utilized in other embodiments of the present invention.
Referring to FIG. 2 , in accordance with one embodiment of the present invention, the coordinating software 16 begins by determining whether there is a radio frequency transmit request from one of the interfaces 20 as determined at diamond 24 . If so, a check at diamond 26 determines whether the other of the interfaces 20 is currently receiving a signal. If not, the interface 20 requesting permission to transmit is authorized to transmit as indicated in block 34 . If another interface is currently receiving a signal, as determined in diamond 26 , transmission may be deferred as indicated in block 28 .
At diamond 30 , the relevancy of the information being received is assessed. For example, if the information being received is of relatively low importance, and the transmission is of relatively high importance, the reception may be deferred for receipt upon retransmission at a later time. Generally, relevancy of information is determined by conventional packet filters.
If the relevancy of the received information is known, a check at diamond 32 determines how important or timely is the data being received. This determination, in one embodiment, may involve a comparison of the importance of the information being transmitted and the importance of the information being received. In addition, the time sensitivity of the information being received and transmitted may be weighed. If the data is considered relevant, meaning that the data is of sufficient timeliness or importance, the transmission may continue to be deferred. However, if the data is of relatively low relevance, the transmission may be allowed to proceed. In some cases relevancy may also be weighed by determining whether the data will automatically be available for reception at periodic intervals in the future.
Thus, in some embodiments of the present invention, communications over independent wireless networks may be controlled to reduce interference through the operation of the application 16 and a general purpose processor 12 . In some embodiments, this allows a single wireless device to participate in more than one networks and/or to use more than one wireless protocol.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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A wireless device may include two or more wireless interfaces capable of transmitting and/or receiving signals over separate wireless networks. To reduce the likelihood of interference, a processing unit may determine whether to permit a transmission under one wireless network when a reception under another wireless network is already in progress.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a U.S. National-Stage entry under 35 U.S.C. §371 based on International Application No. PCT/EP2007/002752, filed Mar. 28, 2007, which was published under PCT Article 21(2) and which claims priority to German Application No. 102006016159.9, filed Apr. 6, 2006, which are all hereby incorporated in their entirety by reference.
TECHNICAL FIELD
The technical field relates to a front section for a motor vehicle with a bumper and a radiator module arranged behind the bumper.
BACKGROUND
The bumper of such a front section is provided in order to deform in a plastic fashion during a collision with an obstacle or with another vehicle and to purposefully absorb kinetic energy during this process. If the extent of the deformation is greater than an air gap that usually exists between the bumper and the radiator module, the bumper and the radiator come in contact with one another and the radiator is also deformed such that a costly repair or replacement thereof is required. The structure of the radiator mainly has thin sheets with little load-bearing capacity, the deformation of which hardly contributes to the desired absorption of kinetic energy. A minor collision, however, may already cause these thin sheets to deform to such a degree that the radiator is rendered inoperative. If this occurs, the vehicle can no longer be driven and needs to be towed, namely even if the accident otherwise result in body-work damage only.
In view of the foregoing, at least one objective exists for developing a front section for a motor vehicle that can be repaired with low expenditures after a collision and reduces the risk of having to tow the vehicle due to damages to the radiator only. In addition, other objectives, desirable features, and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.
SUMMARY
According to an embodiment of the invention, this at least one objective, and other objectives, desirable features, and characteristics, is attained in that the radiator module in a motor vehicle front section with a bumper and a radiator module arranged behind the bumper is held by first and separable second holding means. The first holding means allow a movement of the radiator module with one degree of freedom in a direction facing away from the bumper when the second holding means are separated, and in that the second holding means can be separated by the rearward yielding motion of the bumper. This construction enables the radiator module to evade the bumper during a rearward yielding motion thereof, namely without having to overcome a noteworthy resistance that could lead to mutual damages of the bumper and the radiator module.
The front section can be realized in a particularly simple fashion if the degree of freedom concerns a pivoting motion. In this case, the first holding means themselves are able, in particular, to define a pivoting axis for the evasive motion of the radiator module.
The radiator module and the bumper should be separated by a gap such that not all rearward yielding motions of the bumper necessarily affect the radiator module.
The second holding means that can be separated by the rearward yielding motion of the bumper may have, in particular, a clamp that is open in the longitudinal direction of the vehicle and a projection inserted into the open side of the clamp. In this case, the projection may be solidly connected to the radiator module and the clamp may be solidly connected to a support structure of the front section that is rigid under normal operating conditions of the vehicle or, vice versa, the clamp may be connected to the radiator module and the projection may be connected to the support structure.
The projection may simply be held in the clamp in the form of a frictional engagement; however, the clamp is preferably deformable and the projection engages into the clamp in a form-fitting fashion such that a resistance of the clamp that is adapted to the function needs to be overcome in order to separate the projection from the clamp. The clamp is preferably elastically deformable such that it is merely required to press the projection back into the clamp in order to restore the arrangement of the radiator module.
The radiator module preferably comprises a radiator and a frame that encloses the radiator. Since the frame does not have to have any heat exchanger properties, it can essentially be constructed with consideration of its dimensional stability and strength only. The frame should protrude over a front side of the radiator that faces the bumper so as to ensure that only the frame comes in contact with the bumper and any direct contact between the bumper and the radiator that could damage the radiator is prevented when the bumper yields rearward during a low-speed collision.
This effect can be promoted by providing the frame with pins that protrude toward the bumper to both sides of the radiator.
The radiator can also be protected by providing the frame with a yoke that spans the front side of the radiator.
In order to protect the radiator, it is also practical that a rear side of the bumper that faces the radiator module has a concave contour.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
FIG. 1 shows a perspective representation of the components of a motor vehicle front section that are relevant to embodiments of the invention, namely according to a first embodiment of the invention;
FIG. 2 shows a schematic sectional representation of the front section in the normal state;
FIG. 3 shows a schematic sectional representation analogous to FIG. 2 in case of a collision; and
FIG. 4 shows a second embodiment in the form of a representation analogous to FIG. 1 .
DETAILED DESCRIPTION
The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding summary and background or the following detailed description.
FIG. 1 shows a perspective top view of a bumper 1 and a radiator module 2 according to an embodiment of the present invention, namely in the relative position that these components assume in an intact motor vehicle front section. The bumper is essentially realized in the form of a metallic hollow profile that is fixed on a not-shown rigid front section of the car body by means of (not-shown) support arms that can be compressed in the longitudinal direction of the vehicle, namely so-called crash boxes. The bumper 1 and the crash boxes are conventionally designed such that they deform in a plastic fashion in case of a collision. Consequently, the bumper 1 can yield rearward during a collision in the longitudinal direction of the vehicle. In an initial phase of the deformation process, the deformation is concentrated on the crash boxes and the bumper 1 such that the front section is protected from damages that require costly and labor-intensive repairs if a minor collision occurs.
The radiator module comprises a radiator 3 of conventional design that is enclosed by a frame 4 of plastic or metal that is also referred to as a fan bracket. In the illustration according to FIG. 1 , the frame 4 is reduced to two profiled parts to the left side and the right side of the radiator 3 ; alternatively, the radiator 3 could also be enclosed by a peripheral frame.
Two pins 9 on the upper ends of the essentially vertical profiled parts of the frame 4 represent first holding means for mounting the radiator module 2 on the front section of the vehicle and engage into openings of not-shown carrier parts that are solidly connected to the front section of the vehicle. Once the pins 9 are engaged in the openings, the radiator module 2 is able to carry out a limited pivoting motion about a pivoting axis that horizontally extends through the two pins 9 in the transverse direction of the vehicle, but not a translatory motion of the radiator module 2 as a whole.
The two profiled parts of the frame 4 respectively carry a lug 5 that laterally protrudes at the height of the bumper 1 . An arbor 6 protrudes from this lug toward the bumper 1 . Two laterally protruding pins 7 of the frame profile are held in a form-fitting fashion in elastic clamps 8 that are solidly connected to the front section of the vehicle. They represent second holding means for mounting the radiator module 2 on the front section of the vehicle.
Naturally, the first holding means may also be realized in the form of pins on the lower ends of the profiled parts of the frame 4 or pins that laterally protrude from the profiled parts parallel to the pins 7 may define the axis of a pivoting motion of the radiator.
The function of the embodiment of the invention is shown more clearly in FIG. 2 , in which the bumper 1 is illustrated in the form of a sectional representation and part of a frame 4 of the radiator module 2 with its lug 5 , the arbor 6 and the pin 7 is illustrated in the form of a side view. In the intact state shown, the bumper 1 is separated from the radiator module 2 by a gap 10 , and the bumper 1 and the arbor 6 lie opposite of one another at the same height. When the bumper 1 is pushed rearward during a collision as shown in FIG. 3 , the gap 10 is reduced and the bumper 1 impacts on the arbor 6 of at least one of the two profiled parts and thusly pushes the radiator module 2 toward the rear. During this process, the pins 7 press apart the limbs of the elastically deformable clamps 8 and are ultimately released from the clamps 8 . In this state, the radiator module 2 is able to give way to the pressure of the bumper 1 without noteworthy resistance and to yield rearward as long as sufficient space is available on the rear side of the radiator module 2 as shown on the right side in FIG. 3 and FIG. 4 . The radiator 3 is only damaged between the bumper 1 and an obstacle arranged on the rear side of the radiator, usually an engine block or an exhaust gas system, if the collision is so severe that this space is also used up. After minor collisions, however, it suffices to repair the damages to the crash boxes and, if applicable, the skin of the car body; the radiator module 2 can be simply snapped back into the clamps 8 and then reused.
If the radiator 3 was not damaged during the collision, it can continue to fulfill its function adequately such that the vehicle is able to reach a repair shop without assistance, namely even if the radiator was separated from the clamps 8 and pushed rearward.
It would also be conceivable, in principle, to refrain from dividing the radiator module 2 into the radiator 3 and the frame 4 and to arrange the arbors 6 or another element that comes in contact with the rearward yielding bumper directly on the radiator. However, the aforementioned division provides the advantage that damaged arbors 6 or pins 7 resulting from a collision can be quickly and inexpensively repaired by exchanging the corresponding components of the frame 4 (i.e., the radiator itself requires no repairs).
According to FIG. 1 , the bumper 1 has a curved shape with a concave rear side that faces the radiator module 2 . During a collision, in which the bumper 1 is about symmetrically subjected to a load that is distributed over its width, the curvature of the bumper 1 is preserved such that this curvature ensures that the bumper 1 impacts on the arbors 6 and displaces the radiator module 2 out of the clamps 8 before the bumper can actually come in contact with the radiator 3 .
During a collision with a narrow obstacle such as a tree, the bumper 1 is only subjected to a load in a small section of its width and it is possible that the bumper 1 buckles. FIG. 4 shows an embodiment that also makes it possible to protect the radiator 3 in such instances. In this case, the two arbors 6 are replaced with a rib 11 that is curved forward and extends from one of the vertical profiled parts of the frame 4 to the other vertical profiled part at the height of the bumper 1 . This rib 11 is able to absorb and introduce the pressure of the bumper 1 into the frame 4 if the bumper 1 situated in front of the radiator 3 buckles such that it is also possible for the radiator module 2 to yield rearward in such instances in order to prevent damages to the radiator 3 .
While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.
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A front section for a motor vehicle is provided that includes, but is not limited to a bumper and a radiator module arranged behind the bumper. The radiator module is held by means of first and separable second holding means. The first holding means allow a movement of the radiator module with one degree of freedom in a direction facing away from the bumper when the second holding means are separated, and wherein the second holding means can be separated by a rearward yielding motion of the bumper.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to systems for unloading fluids from generally upright tubular members of a wellbore. In another aspect, the invention concerns a method and apparatus for efficiently and effectively unloading fluids from production tubing of a subterranean hydrocarbon well by utilizing a fuel cell to generate content-lifting gases in the tubing.
[0003] 2. Discussion of Prior Art
[0004] In preparation for producing, and during the production of, hydrocarbons from subterranean formations, it is often necessary to unload the fluid contents of a fluid-filled production tubing string before hydrocarbon production can begin or continue. For example, certain processes either involve introducing fluid into the production tubing that must later be removed prior to production (e.g., drilling fluids, fracturing fluids, completion fluids, production fluids, etc.) or require fluids already in the production tubing to be removed (e.g., water, oil, condensate, etc.).
[0005] There are systems known in the art for unloading contents from well tubing. For example, well operators typically run coiled tubing into the well and pump the contents out of the production tubing. It is also known in the art to introduce certain gases (e.g., nitrogen) into a liquid-filled tubular to create a “bubbling” lifting force to assist in removing liquid from the tubing string.
[0006] These prior art systems are problematic and suffer from several limitations. For example, the coiled tubing, while effective, is inefficient as it is considerably time-consuming and requires significant additional equipment and materials to operate. Prior methods of unloading a well using gases are ineffective and may expose the formation or casing annulus to undesired elevated pressure in order to introduce sufficient gases into the well.
SUMMARY OF THE INVENTION
[0007] The present invention provides an improved system for unloading fluids from tubular members (e.g., tubing or casing) of a wellbore that does not suffer from the problems and limitations of the prior art systems as set forth above. The inventive system provides a way to effectively and efficiently unload fluids from a well tubing or casing without exposing the formation or casing to undesired elevated pressure.
[0008] In accordance with one embodiment of the present invention, a method of unloading a fluid from a generally upright tubular member of a wellbore is provided. The method comprises the steps of: (a) placing a combustible fuel cell inside the tubular member under the fluid to be unloaded; (b) burning the fuel cell to generate a gas in the tubular member; and (c) using the gas to force at least a portion of the fluid upward out of the tubular member.
[0009] In accordance with another embodiment of the present invention, an apparatus for unloading a fluid contained in a generally upright tubular member of a wellbore is provided. The apparatus generally comprises a combustible and expandable fuel cell, a cap coupled to the fuel cell, and an ignition device coupled to the fuel cell. The fuel cell is adapted to be received in the tubular member. The fuel cell defines an internal chamber which is adapted to be filled with a gas generated by the fuel cell when the fuel cell is burned. The cap is operable to hold the gas in the internal chamber until the pressure of the gas in the internal chamber causes the fuel cell to expand sufficiently to form a seal with the tubular member. The ignition device is operable to initiate burning of the fuel cell when the ignition device is actuated.
[0010] In accordance with a still further embodiment of the present invention, a wellbore extending into a subterranean formation is provided. The wellbore comprises a generally upright tubular member, a fluid disposed in the tubular member, a combustible fuel cell disposed in the tubular member generally below at least a portion of the fluid, and an ignition device coupled to the fuel cell. The fuel cell is operable to generate a gas when burned. The ignition device is operable to initiate burning of the fuel cell when the ignition device is actuated.
[0011] Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0012] Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:
[0013] [0013]FIG. 1 is a partial sectional view of an apparatus for unloading well tubing constructed in accordance with the principles of the present invention and shown schematically in a plugged production tubing inside a perforated well casing;
[0014] [0014]FIG. 2 is a sectional view of the apparatus taken substantially along line 2 - 2 of FIG. 1; and
[0015] [0015]FIG. 3 is apartial sectional view of an alternative apparatus for unloading well tubing constructed in accordance with the principles of the present invention and shown schematically in a plugged production tubing inside a perforated well casing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Turning initially to FIG. 1, the apparatus 10 for unloading well tubing selected for illustration is shown submerged at the bottom of a production tubing T for producing hydrocarbons from a subterranean well. The production tubing T is filled with fluid (e.g., water, oil, condensate, drilling fluids, fracturing fluids, completion fluids, production fluids, etc.). The production tubing is plugged by a plug P. The tubing T is located in a perforated well casing C. However, the principles of the present invention are applicable to unload the contents of virtually any kind of tubular in any type of well. For example, the present invention could be utilized to unload fluid contents from a well casing. The apparatus 10 broadly includes a combustible fuel cell 12 operable to generate content-lifting gases as it combusts, a cap 14 cooperating with the cell 12 to provide a desired seal, and an ignition assembly 16 operable to ignite the cell 12 .
[0017] The fuel cell 12 is adapted to be inserted into the tubing T and positioned below the fluid to be unloaded therefrom. In particular, the illustrated fuel cell 12 is generally cylindrical in shape and includes an upper end 18 and a lower end 20 axially spaced from the upper end 18 . The fuel cell 12 preferably has a generally annular cylindrical configuration and defines an outer diameter (prior to ignition) that is less than the inner diameter of the tubing T (e.g., typical production tubing has an inner diameter between 2 and 7 inches). Because the fuel cell 12 is inserted into a fluid-filled well tubing, it is important that the outer diameter of the fuel cell 12 provide sufficient clearance between the inner wall of the tubing T to allow the fuel cell 12 to be submerged to the desired position—i.e., below the fluid to be unloaded (e.g., typically this will be towards or at the bottom of the well tubing). However, for purposes that will subsequently be described, it is further important that the outer diameter of the illustrated fuel cell 12 be as large as possible and still allow the desired insertion clearance.
[0018] As shown in FIGS. 1 and 2, the illustrated fuel cell 12 defines an internal burn hole 22 . The burn hole 22 is generally located around the central longitudinal axis of the fuel cell 12 and extends between the upper and lower ends 18 , 20 . The burn hole 22 is configured to influence the rate at which the fuel cell 12 burns once it is ignited (e.g., accelerating over time). It is believed the rate at which the fuel cell 12 burns will be proportional to the surface area of fuel exposed to the hot gases created by the burn. For purposes that will subsequently be described, it is important for the illustrated fuel cell 12 to burn slowly at first (e.g., just after ignition) so that the corresponding pressure created by the gases formed in the burn also builds slowly at first. In this regard, the surface area of fuel exposed to the burn will, upon ignition, initially be limited to the surface area of fuel defining the internal burn hole 22 .
[0019] However, as the fuel burns, the diameter of the bum hole 22 will expand, thereby exposing more surface area of fuel to the burn. It is believed that as the surface area of fuel exposed to the burn increases, the rate of combustion of the fuel cell also increases.
[0020] As previously indicated, the fuel cell 12 is combustible and operable to generate content-lifting gases as it combusts. In this regard, the illustrated fuel cell 12 is preferably formed from an expandable propellent-type material that burns at a relatively slow rate of combustion, produces relatively large amounts of gases as it burns, burns without utilizing heat or oxygen external to the cell 12 , and substantially incinerates when burned.
[0021] As will subsequently be described in detail, the fuel cell 12 may operate as a “rocket assist” to create a gas bubble that drives the fluid up and out of the tubing string T. Depending on the application, a tubing string could be as much as 10,000 feet deep and filled with fluid that must be unloaded. It is therefore important that the fuel cell 12 burn at a slow enough rate of combustion to prevent damaging the tubing string T and create a sufficient and sustained lifting force to unload the vast amount of fluid out of the top of the tubing string T. For example, an explosion-type burn is undesired because it could both damage the tubing string and may not sufficiently expel the fluid out of the top of the tubing string. In an exemplary application involving a 7 inch diameter tubing filled with fluid to a depth of 5000 feet, a representative burn rate would be 2-3 minutes for a fuel cell having an axial length of around thirty feet. It is also important that the fuel cell 12 produce large amounts of gases as it burns in order to create the necessary lifting force to drive the fluids up the tubing string T and expel them out of the top of the string T. Because the fuel cell 12 is ignited once it has been submerged beneath the fluids to be unloaded, it is further important that the cell 12 burn without the need to utilize heat or oxygen from a source external to the cell 12 . To facilitate cleaning the tubing string after it has been unloaded, it is preferred that the fuel cell 12 substantially incinerate upon burning. In this regard, it is preferred that the fuel cell 12 be formed from a propellant-type material that exists in a solid form (e.g., gel-like, etc.) to eliminate the need for any casing structure. An exemplary material suitable for the construction of the fuel cell 12 is available from Atlantic Research Corporation, Gainesville, Va., under the trade name ARCITE 479. However, it is within the ambit of the present invention to utilize virtually any material having the desired burn characteristics. For example, a liquid fuel cell packed in a solid casing could be utilized.
[0022] The cap 14 cooperates with the fuel cell 12 to provide a seal below the fluid to be unloaded from the well tubing T after the fuel cell 12 is positioned therein. In the illustrated apparatus 10 , the cap 14 is integrally formed with the fuel cell 12 proximate the upper end 18 and is formed from a similar combustible propellant-type material. The cap 14 is configured to control the pressure within the fuel cell 12 after the cell 12 is ignited until a threshold pressure is achieved. In particular, the fuel cell 12 , once ignited, begins to burn thereby creating gases. During these early stages of the burn, the cap 14 prevents the gases from exiting the upper end 18 of the cell 12 thereby causing pressure to build within the cell 12 . As the pressure builds, it causes the fuel cell 12 to radially expand until the circumferential surface thereof seals against the inside wall of the tubing T. Once the cell 12 seals against the tubing T, the cell 12 continues to burn (at a faster rate) producing more gases and thereby building further pressure. During these middle stages of the burn, the cap 14 continues to prevent the gases from exiting the upper end 18 of the cell 12 . During these middle stages of the burn, the pressure eventually overcomes the friction forces between the circumferential surface of the cell 12 and the inner wall of the tubing T causing the unburned portion of the cell 12 to begin to shift upwards. Although the unburned portion of the cell 12 loses its frictional grip on the internal wall of the tubing T, it maintains the seal between the contents above the cell 12 and the gases therebelow. As the cell 12 shifts up the tubing T, fluid above the cell 12 is driven up the tubing T. Once the cell 12 has begun to drive the fluid up the tubing T, the cell 12 continues to burn (at still a faster rate) producing even more gases and thereby building even further pressure. During these late stages of the burn, the cap 14 ruptures allowing the gases within the cell 12 to expand out of the cell 12 . As the gases expand out of the cell 12 , they force the fluid inside the tubing T upward until the fluid is expelled therefrom. Once the fluid is expelled from the tubing T, the gases vent to the surface atmosphere out of the tubing T. During these final stages of the burn, any fuel remaining in the tubing T continues to burn until it is consumed leaving the tubing T unloaded and clean.
[0023] The illustrated apparatus 10 includes a bottom cap 24 integrally formed with the fuel cell 12 proximate the lower end 20 . The bottom cap 24 is formed from a similar combustible material so that it is consumed during the final stages of the burn. However, the bottom cap 24 is configured to withstand pressure in excess of the pressure at which the cap 14 ruptures. In this manner, the bottom cap 24 protects anything down-hole of the cell 12 from the gases generated thereby. For example, the bottom cap 24 prevents the gases generated by the cell 12 from penetrating the well, the perforations, the formation, etc. It is within the ambit of the present invention to utilize alternative fuel cell configurations that do not utilize a bottom cap. It is also within the ambit of the present invention to utilize a plug (e.g., the plug P) to prevent the cell-generated gases from escaping down-hole. If a plug is used, it must be placed in the well tubing prior to inserting the fuel cell (e.g., in any manner commonly known in the art) and can be removed once the well is unloaded (e.g., using a slick line, etc.). It is preferred to utilize a plug to protect the sand face of the formation when the well has already been perforated.
[0024] As previously indicated, the ignition assembly 16 is operable to ignite the fuel cell 12 after the cell 12 is positioned in the tubing T. The illustrated assembly 16 includes an electric triggering device 26 , a communication wire 28 , and a fuse 30 . The triggering device 26 is located on top of the cap 14 and includes a connecting element (not shown) adapted to electrically, mechanically, and removably connect the triggering device 26 to a well line. For example, the illustrated apparatus 10 is preferably coupled to a wire-line 31 for inserting the apparatus 10 into the well tubing T and setting it in its submerged position therein. The wire-line 31 , in a manner known in the art, also carries electric current from a source external to the well tubing T. The wire-line 31 conveys the electric current to the triggering device 26 . The triggering device 26 is electrically coupled to the communication wire 28 . The wire 28 is in firing communication with the fuse 30 . The triggering device 26 generates a firing signal that is conveyed through the communication wire 28 to the fuse 30 where the firing signal causes the fuse 30 to light. The fuse 30 , once lit, starts the fuel cell 12 burning. The fuse 30 is positioned in the burn hole 22 adjacent the lower end 20 of the cell 12 so that the cell 12 begins burning at the lower end 20 and burns radially outward from the burn hole 22 . It is preferred that the wire-line 31 be removed once the firing signal has been generated. It is within the ambit of the present invention to utilize alternative ignition assemblies. For example, the triggering device 26 could be a time trigger or a pressure trigger that do not require the use of a wire-line to either set the apparatus 10 or deliver electric current thereto. However, it is important that the ignition assembly be able to ignite the cell 12 at a desired location after the cell 12 is submerged in the desired position in the well tubing T.
[0025] It is within the ambit of the present invention to utilize various alternative configurations, designs, materials, etc. for the apparatus for unloading well tubing. However, it is important that the apparatus is configured to be submerged in the fluid in the well tubing, ignited therein, and operable to generate content-lifting gases which can be used to drive the fluid contents up the tubing and expel them therefrom. An alternative embodiment is the apparatus 100 for unloading well tubing as illustrated in FIG. 3. The apparatus 100 is illustrated in an environment similar to the environment previously discussed above with respect to the apparatus 10 . That is, the apparatus 100 is illustrated submerged toward the bottom of a plugged fluid-filled well tubing T that is incased in a perforated well casing C. The apparatus 100 broadly includes a combustible fuel cell 102 operable to generate content-lifting gases as it combusts, a plunger 104 operable to displace fluids in the tubing T when shifted within tubing T, and an ignition assembly 106 operable to ignite the cell 102 .
[0026] The fuel cell 102 is similar to the previously discussed fuel cell 12 , however, for reasons that will subsequently become clear, the fuel cell 102 need not be expandable and therefore does not include either a burn hole or a bottom cap. The fuel cell 102 is generally cylindrically shaped and includes axially spaced upper and lower ends 108 and 110 , respectively. Other than the need to be expandable, the fuel cell 102 includes all of the burn qualities previously detailed with respect to the fuel cell 12 and is preferably formed of the same or a similar material.
[0027] The plunger 104 may provide a slidable seal below the fluid to be unloaded from the well tubing T after the fuel cell 102 is positioned in the well tubing T. The plunger 104 is positioned proximate the upper end 108 of the fuel cell 102 . The illustrated plunger 104 is shown in contact with and coupled to the cell 102 , however, it is within the ambit of the present invention for the plunger to be spaced from the upper end 108 of the fuel cell 102 . The plunger 104 may be adapted to create and maintain a mechanical seal with the inside wall of the well tubing T. In this regard, the plunger 104 is preferably not formed from a propellant-type material. There are several ways known in the art to create a down-hole mechanical slidable seal inside a well tubing (e.g., elastomeric seals, spring-biased sealing pads, etc., that are typically used in artificial plunger lift systems) and any of these can be utilized to seal the plunger 104 . It is also within the ambit of the present invention to utilize non-mechanical seals, such as a grooved cap sealed by upward gas flow. However, it is important that the seal be adapted to slide up the well tubing T while maintaining a relationship with the inner wall of the well tubing T sufficient to displace at least a portion of the fluid contents to be unloaded. In this regard, the plunger 104 may not completely seal against the inner wall of the well tubing T. It is within the ambit of the present invention to utilize a plunger 104 having an outer diameter that provides sufficient clearance from the inner diameter of the well tubing T to allow the apparatus to “drift” down the fluid-filled tubing T during insertion into the desired unloading position in the tubing T. However, the clearance between the outer diameter of the plunger 104 and the inner diameter of the tubing T should be sufficiently minimal so that when the fuel cell 102 is ignited and begins to generate content-lifting gases, the plunger 104 isolates at least a substantial portion of the fluid contents to be unloaded from the fuel cell 102 .
[0028] As the fuel cell 102 begins to burn, the pressure of the generated gas builds below the plunger 104 until the gases drive the plunger 104 up the well tubing T. As the plunger 104 slides up the tubing T, the fluid above the plunger 104 is also driven up the tubing string T until it is expelled out of the top of the tubing T.
[0029] The ignition assembly 106 , unlike the previously described assembly 16 , preferably comprises a pressure triggering device. The ignition assembly 106 is coupled to the lower end 110 of the cell 102 . In one manner known in the art, the pressure trigger of the assembly 106 ignites once the trigger is exposed to a threshold pressure (e.g., ignition instigated by the weight of the cell 102 and the fluids thereabove compressing the assembly 106 against the plug toward the bottom of the tubing T). Once the trigger is ignited, it burns through the lower end 110 of the cell 102 thereby igniting the cell 102 . An exemplary pressure trigger device suitable for use in the ignition assembly 106 is available from Pacific Scientific Energetic Materials Co., Chandler, Ariz. as model no. PS-190 CP/HNS.
[0030] The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention.
[0031] The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.
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A system for unloading fluids from a generally upright tubular member of a wellbore wherein a combustible fuel cell can be placed in the tubular member below the fluid and ignited to generate gasses. The gasses generated by the burning of the fuel cell can be used to force at least a portion of the fluid upward out of the tubular member.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of and claims priority to pending U.S. patent application Ser. No. 14/120,528, entitled “Shaped Charge Casing Cutter,” filed May 29, 2014.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
FIELD OF THE INVENTION
[0003] The present invention relates to shaped charge tools for explosively severing tubular goods including, but not limited to, pipe, tube, casing and/or casing liner.
BACKGROUND OF THE INVENTION
[0004] The capacity to quickly, reliably and cleanly sever a pipe or well casing deeply within a wellbore is an essential maintenance and salvage operation in the petroleum drilling and exploration industry. Cutting large, 7 inch to 20 inch nominal diameter casing and casing liner is particularly challenging. Generally, the industry relies upon mechanical, chemical or pyrotechnic devices for such cutting. Among the available options, shaped charge (SC) explosive cutters are often the simplest, fastest and least expensive tools for cutting pipe in a well. The devices are typically conveyed into a well for detonation on a wireline or length of coiled tubing.
[0005] Typical explosive pipe cutting devices comprise a consolidated wheel of explosive material having a V-groove perimeter similar to a V-belt drive sheave. The surfaces of the circular V-groove are clad with a thin metal liner. Pressed contiguously against the metal liner is a highly explosive material such as HMX, RDX or HNS.
[0006] This V-grooved wheel of shaped explosive is aligned coaxially within a housing sub and the sub is disposed internally of the pipe that is to be cut. Accordingly, the plane that includes the circular perimeter of the V-groove apex is substantially perpendicular to the pipe axis.
[0007] Upon ignition of the explosive, the explosion shock wave reflects off the opposing V surfaces of the grooved wheel to focus onto the respective metal liners. The opposing liners are driven together into a collision that produces a fluidized mass of liner material. Under the propellant influence of the high impingement pressure, this fluidized mass of liner material flows lineally and radially along the apex plane at velocities in the order of 22,000 ft/sec, for example. Resultant impingement pressures against the surrounding pipe wall may be as high as 6 to 7×10 6 psi thereby locally fluidizing the pipe wall material.
[0008] This principle may be applied to large diameter pipe such as well casing which may be cut while positioned within a wellbore with a toroidal circle of explosive having an outside face formed in the signatory V-groove cross-section. This toroidal circle of explosive is placed and detonated within a toroidal cavity of a housing. However, formation of an explosive torroid of sufficient size to sever a large diameter casing requires relatively large quantities of explosive. As an integral unit, such quantities of explosive exceed prudent transportation limitations. For practical reasons of transport and safety, therefore, the mass of the toroidal explosive circle is divided into multiple, small quantity modules of cross-sectional increments which are transported to a well site in separate, isolated packages.
[0009] Explosively cutting a 20 inch casing may require a shaped charge of as much as 1000 gms. (35.27 ounces) of high explosive (ex. HMX). However, international standards of transportation safety (United Nations Recommendations on the Transport of Dangerous Goods, Edition 17, Vol. I, Chapter 2.1, Division 1.4) limit the public transport of a single unit of hazard class or high explosive to 45 gm (1.59 ounces). Consequently, to transport a shaped charge cutter of size sufficient to cut a 20 inch casing, it is essential for the explosive elements of the cutter to be designed for shipment as a multiplicity of small, less than 38 gm./unit, modules configured for operational assembly at the point of use.
[0010] Unfortunately, the environmental circumstances of a drilling rig floor, which is where final cutter assembly must occur, are often severe and usually not conducive to the attentive care required for final assembly of a high explosive tool. Hence, there are strong incentives to design the individual explosive modules with the greatest degree of assembly ease and tolerance. But large module assembly tolerance often results in collective space between modules. In the case of modular assembly for shaped charges, such assembly space can severely diminish the cutter capability.
[0011] Other issues for large diameter casing cutters arise with deep wells under considerable hydrostatic pressure. Large surface areas for prior art casing cutter housings may be distorted under deep well fluid pressure, also resulting in reduced cutting capacity or a malfunction of the tool.
BRIEF SUMMARY OF THE INVENTION
[0012] The present casing cutter invention comprises several design and fabrication advantages including a substantially solid structural interior that is substantially impervious to high well pressure. Shaped charge explosive material is distributed in modules around the full circle of an approximate toroidal cavity that is held open against well pressure by a full-circle belting structure.
[0013] Preferably, the modules are further divided into smaller units corresponding to upper and lower half sections of the approximate toroid. The shaped charge metal liner is independently fabricated as a pair of matching cone frustums.
[0014] Collective tolerance space between the modules and modular units of explosive material is closed around the toroid circumference by paper card stock shims between adjacent explosive modules.
[0015] The back-side surfaces of the shaped charge assembly may be resiliently biased into intimate contact against the liner cone surfaces by an O-ring spring bearing upon the explosive module back-sides. A gap between the adjacent apex surfaces of the modules accommodates module fabrication tolerances.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention is hereafter described in detail and with reference to the drawings wherein like reference characters designate like or similar elements throughout the several figures and views that collectively comprise the drawings. Respective to each drawing figure:
[0017] FIG. 1 is a cross-section of a preferred embodiment of the invention in assembly with the housing, centralizer and top sub.
[0018] FIG. 2 is a plan view of the initiation spool.
[0019] FIG. 3 is an elevation view of the initiation spool.
[0020] FIG. 4 is a plan view of the explosive assembly.
[0021] FIG. 5 is a plan view of an individual explosive unit.
[0022] FIG. 6 is an end elevation view of an individual explosive unit.
[0023] FIG. 7 is a side elevation view of an individual explosive unit.
[0024] FIG. 8 is a pictorial view of the metallic liners.
[0025] FIG. 9 is a plan view of an alternate initiation spool.
[0026] FIG. 10 is a cross-section of the invention provided with buffer chambers and an alternate detonation configuration.
DETAILED DESCRIPTION OF THE INVENTION
[0027] As used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly”, “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate. Moreover, in the specification and appended claims, the terms “pipe”, “tube”, “tubular”, “casing”, “liner” and/or “other tubular goods” are to be interpreted and defined generically to mean any and all of such elements without limitation of industry usage.
[0028] Referring to FIG. 1 , a top sub 10 is formed with an axial cavity 12 for receipt of a detonator sub-assembly not shown. Internal threads 14 proximate of the sub body upper end provide a convenient mechanism for securing the top sub 10 to a tubing string, for example. External threads 16 , as shown in FIGS. 1 and 10 , at the lower end of the top sub 10 secure the top sub to the upper housing plate 22 of the shaped charge housing 20 .
[0029] The shaped charge housing 20 assembly basically comprises four major components. Upper and lower housing plates 22 and 24 are separated by initiation spool 26 . The housing plates and initiation spool are all of substantially circular perimeter. The upper and lower housing plates 22 and 24 are secured into a belting ring 28 with a plurality of threaded fasteners 29 . Notably, the belting ring fit with the housing plate perimeters is designed to oppose distortions and closure of the toroidal cavity 21 between the plate perimeters due to high external fluid pressure. O-ring seals 25 environmentally secure the toroidal cavity 21 around the housing perimeter inside of the belting ring. The belting ring outside diameter is only slightly less than the inside diameter of the casing that is to be severed. Centering springs 27 may be secured to the housing to project radially outward by a predetermined distance determined by the internal diameter of the casing to be severed.
[0030] The belting ring 28 thickness is notched about its internal perimeter to provide a narrow penetration band 23 in the radial expansion plane of the shaped charge cutting jet.
[0031] Referring to FIGS. 2 and 3 , the initiation spool 26 may be a substantially solid disc having parallel face planes and at least one transverse detonator cord boring 30 between the face planes that is intersected at the disc center by a detonator aperture 32 . The perimeter of the disc is channeled by a detonator cord confining groove 34 . Preferably, the transverse detonator cord 36 is continuous between opposite outer perimeters of the initiation spool 26 for termination at close adjacency against adjacent detonator cord in the confining groove 34 , while confining groove 34 is in close adjacency against explosive units 54 . The two arcuate cord portions 38 that form a detonating circle have respective opposite distal ends that terminate against side elements of the transverse cord.
[0032] With further reference to FIG. 1 , the upper and lower housing plates 22 and 24 are formed to substantially the same profile. In an embodiment, the annular edges 40 and 41 of the respective housing plates 22 and 24 are substantially concentric with corresponding center sections 42 and 44 . The annular edge 40 of the upper plate 22 is in parallel alignment with the plane of the circular plate center section 42 . As a mirror reflection, the annular edge 41 of the lower housing plate 24 is in parallel with the plane of the circular plate center section 44 .
[0033] An approximately toroidal cavity 21 is formed within the interior surfaces of the plate rims and the belting ring to confine a circular assembly of explosive modules 50 . Each module 50 is a radial increment of a shaped charge circle. The plan view of FIG. 4 illustrates the circular alignment of the modules 50 with juxtaposed radial joint planes 52 . Each module 50 comprises a matching pair of explosive units 54 , with no unit exceeding 45 gms. of explosive, for example. The three orthographic views of FIGS. 5 , 6 and 7 show a single unit 54 having a body 56 of compressed, high explosive material.
[0034] As the individual units are positioned against a respective housing plate interior surface 49 in the circle illustrated by FIG. 4 , it will be understood that each unit must be formed to a small undersize tolerance for assembly convenience. When all of the units are positioned and pressed together, collectively, this necessary tolerance is accumulated as an intolerable space between the first and last units that may be 0.254 mm (0.010 inches) or more. Leaving such a space may severely influence the shaped charge performance. An unfilled inter-unit space of 1.588 mm (0.0625 inches) has been measured to reduce cutting penetration by half. Of course, this space may be packed with loose explosive but such a solution is not only time consuming but hazardous.
[0035] Filling the spaces with metallic shims has also been found to be unsatisfactory. Cutting performance is nevertheless reduced. Surprisingly, it has been found that the spaces may be filled with “card stock” paper shims 53 without measurable loss of cutting penetration. Typical specifications for card stock paper include a paper sheet that is calendared to an approximate density range of 135 to 300 g/m 2 (3.982 oz./yd. to 8.848 oz./yd.) and thickness range of 0.254 mm to 0.381 mm (0.01 in. to 0.015 in). In practice, the card stock shim is cut into the section shape of an explosive unit as shown by FIG. 7 and inserted in the space between adjacent explosive units 54 . Preferably, only one card stock shim is positioned between an adjacent pair of explosive units 54 . Collective spaces greater than a single card stock thickness may be closed by inserts between multiple pairs of explosive units and/or modules.
[0036] It has long been believed that intimate contact of the shaped charge explosive material with the interior surface 49 of the housing structure enhanced the cutting energy release. U.S. Pat. No. 6,505,559 to J. Joslin et al. assumed this relationship by their disclosed use of “glue” to secure segmented explosive units to a backing plate. However, when practiced in the environment of a drilling rig floor, the difficulties of gluing explosive units in place are numerous. Moreover, Applicants have discovered the intimate relationship to be less critical than originally believed.
[0037] Of far greater importance is the intimate relationship of the explosive with the contiguous liner. In the prior art fabrication process, the independently formed metallic liner is placed in a molding receptacle and powdered explosive distributed over the liner. Subsequently, a forming die is forced against the powdered explosive to compact it against the liner surface and adhere it intimately thereto.
[0038] The present invention procedure calls for a partial assembly of the shaped charge housing 20 by attaching the belting ring 28 to the lower housing plate 24 by means of fasteners 29 . Additionally, the initiation spool 26 is centered upon the lower plate center section 44 . This provides an open but walled circular channel within the belting ring interior perimeter. Within this circular channel, the appropriate number of explosive units 54 are positioned with the outer end face 55 of each explosive unit placed contiguously against the inner face 60 of the belting ring 28 while the inner end face of the explosive units 54 is positioned adjacent to the center section 44 outer perimeter. The outer face 58 of each explosive unit 54 is supported by two or more O-rings 46 , 48 . Contiguous continuity between the several units 54 about the module 50 circle is completed by inserting a required number of shims 53 between one or more pairs of units 54 . Upon this assembly of explosive units 54 , the conical frustum 57 of a first liner half is placed against the inner face 59 of the explosive units.
[0039] Alignment of the upper half of the cutter ring onto the previously assembled lower half begins with positioning the minor diameter edge 62 of the upper frustum 57 against the minor diameter edge 62 of the lower frustum 57 . See FIG. 8 . If correctly dimensioned, the major diameter edge 63 of the upper frustum will be contiguously confined against the upper inside face 60 of the belting ring 28 . The upper layer of explosive units 54 are placed upon the upper liner frustum with contiguous fits against the belting ring and initiation spool 26 outer perimeter. A sufficient number of shims 53 are positioned between adjacent pairs of explosive units 54 to complete the contiguous continuity.
[0040] When the shaped charge housing assembly 20 is completed by securing the upper housing plate 22 to the belting ring 28 , the upper and lower plate O-rings 46 , 48 exert a mutually opposed bias upon the explosive units 54 and the respective frustums 57 .
[0041] It is important to note that the explosive unit 54 dimensions described above provide an open space 65 between the proximate explosive units 54 to accommodate other dimensional tolerance variations. In view of the tightly confined environment of Applicant's explosive cutter assembly and the consequential fluctuations of manufacturing tolerances, a free movement space for the units 54 is essential to assure intimate contact with the liner frustums 57 . Although paper shims 53 successfully fill the circumferential tolerance space between adjacent explosive units 54 , it is the resilient bias of the O-rings 46 that press the units 54 into necessary intimate contact with the liner material 57 .
[0042] FIG. 9 illustrates an alternative embodiment of the invention ignition system in which two concentric layers of HMX comprising a center pellet 31 and an outer initiation pellet 37 are separated by a single initiation spool 33 . In an embodiment, center pellet 31 is a single piece while outer initiation pellet 37 comprises a plurality of increments 39 , none of which exceed regulatory and safety limits. In the depicted figure, the outer initiation pellet 37 is divided into six increments 39 , although it can be appreciated that the segmentation can be greater or lesser depending on the shockwave profile and the regulatory transport requirements. Initiation spool 33 comprises a plurality of grooves 35 which focus and amplify the shock wave created by center pellet 31 , allowing the invention to achieve higher working pressures and lessening the amount of explosive required to achieve equal detonation output to a solid explosive spool. As with the outer initiation pellet 37 , while initiation spool 33 is depicted as having eight grooves 35 , the configuration may vary.
[0043] FIG. 10 illustrates the above configuration in cross-section, showing center pellet 31 , initiation spool 33 , and outer pellet 37 within boring 30 created between the face planes of housing plates 22 , 24 .
[0044] As a further invention enhancement, FIG. 10 illustrates the invention housing as including buffer chambers 74 and 76 within annular channels 75 and 77 . O-rings 80 seal the respective chamber volumes from the downhole fluid environment. The function of these annular channels 75 and 77 and buffer chambers 74 and 76 is to absorb and suppress energy reflections from the housing plates 22 and 24 . Unbuffered, such reflected energy tends to disrupt the planar uniformity of the cutting disc as it erupts from the liner apex. A disturbed cutting disc results in a flared wall cut and an enlarged perimeter of “flash” on the pipe wall about the cutting plane. In can of course be appreciated that while these two improvements are illustrated together in FIG. 10 , these buffer chambers could be used independently of the concentric nested ignition configuration of FIG. 9 , and vice versa.
[0045] While a preferred embodiment of our invention has been illustrated in the accompanying drawings and described in the foregoing specification, it will be understood by those of skill in the art that additional embodiments, modifications and alterations may be constructed from the invention principles disclosed herein. These various embodiments have been described herein with respect to cutting a “pipe.” Clearly, other embodiments of the cutter of the present invention may be employed for cutting any tubular good including, but not limited to, pipe, tubing, production/casing liner and/or casing. Accordingly, use of the term “tubular” in the following claims is defined to include and encompass all forms of pipe, tube, tubing, casing, liner, and similar mechanical elements.
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A shaped charge casing cutter is constructed with the cutter explosive formed into radial section modules aligned in a toroidal cavity between a pair of housing plates. The center sections of the housing plates are contiguously aligned with opposite parallel surfaces of a center disc. The housing plates comprise annular edges or rims, and the rims can be offset from respective center disc planes in opposite directions from each other to form a toroidal cavity. The toroidal cavity is enclosed by a circumferential belt secured to said housing plate rims. V-grooved shaped charge explosive in the form of multiple pi sections is distributed about the cavity to intimately contact a pair of frusto-conical liners. Assembly tolerance space between the pi sections is filled by dense paper card stock.
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PRIORITY CLAIMS
[0001] This application is a continuation of and claims the priority benefit of commonly-assigned co-pending U.S. patent application Ser. No. 14/521,375, filed Oct. 22, 2014 and published as U.S. Patent Application Publication Number 2015/0336301, the entire contents of which are incorporated herein by reference.
[0002] U.S. patent application Ser. No. 14/521,375 is a continuation-in-part of and claims the benefit of priority of commonly-assigned, co-pending U.S. Non-Provisional application Ser. No. 13/756,348 (Attorney Docket No. RO-018-US), filed Jan. 31, 2013, the entire disclosure of which is herein incorporated by reference.
[0003] U.S. patent application Ser. No. 14/521,375 is a continuation-in-part of and claims the benefit of priority of commonly-assigned, co-pending U.S. Non-Provisional application Ser. No. 13/756,370 (Attorney Docket No. RO-019-US), filed Jan. 31, 2013, the entire disclosure of which is herein incorporated by reference.
[0004] U.S. patent application Ser. No. 14/521,375 is a continuation of and claims the priority benefit of commonly-assigned co-pending International Application Number PCT/US2013/038675, filed Apr. 29, 2013, the entire contents of which are incorporated herein by reference. International Application Number PCT/U52013/038675 claims the benefit of priority of commonly-assigned, co-pending U.S. Provisional application Ser. No. 61/798,629 (Attorney Docket No. RO-020-PR), to Boris Kobrin et al., entitled “CYLINDRICAL POLYMER MASK AND METHOD OF FABRICATION”, filed Mar. 15, 2013, the entire disclosure of which is herein incorporated by reference.
[0005] International Application Number PCT/U52013/038675 claims the benefit of priority of commonly-assigned, co-pending U.S. Provisional application Ser. No. 61/641,711 (Attorney Docket No. RO-013-PR), to Boris Kobrin et al., entitled “SEAMLESS MASK AND METHOD OF MANUFACTURING”, filed May 2, 2012, the entire disclosure of which is herein incorporated by reference.
[0006] International Application Number PCT/US2013/038675 claims the benefit of priority of commonly-assigned, co-pending U.S. Provisional application Ser. No. 61/641,650 (Attorney Docket No. RO-014-PR), to Boris Kobrin et al., entitled “LARGE AREA MASKS AND METHODS OF MANUFACTURING”, filed May 2, 2012, the entire disclosure of which is herein incorporated by reference.
[0007] International Application Number PCT/US2013/038675 is a continuation-in-part of and claims the benefit of priority of commonly-assigned, co-pending U.S. Non-Provisional application Ser. No. 13/756,348 (Attorney Docket No. RO-018-US), to Boris Kobrin et al., entitled “CYLINDRICAL MASTER MOLD AND METHOD OF FABRICATION”, filed Jan. 31, 2013, the entire disclosure of which is herein incorporated by reference.
[0008] International Application Number PCT/US2013/038675 is a continuation-in-part of and claims the benefit of priority of commonly-assigned, co-pending U.S. Non-Provisional application Ser. No. 13/756,370 (Attorney Docket No. RO-019-US), to Boris Kobrin et al., entitled “CYLINDRICAL PATTERNED COMPONENT FOR CASTING CYLINDRICAL MASKS”, filed Jan. 31, 2013, the entire disclosure of which is herein incorporated by reference.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0009] This application is also related to commonly-assigned International Patent Application Publication Number WO2009094009, the entire disclosure of which is herein incorporated by reference, and U.S. Pat. No. 8,182,982, the entire disclosure of which are incorporated herein by reference.
FIELD OF THE DISCLOSURE
[0010] The present disclosure is related to lithography methods. More specifically, aspects of the present disclosure are related to rotatable masks, including cylindrical polymer masks and methods of fabrication thereof.
BACKGROUND
[0011] Photolithography fabrication methods have use in a wide variety of technological applications, including micro-scale and nano-scale fabrication of solar cells, LEDs, integrated circuits, MEMs devices, architectural glass, information displays, and more.
[0012] Roll-to-roll and roll-to-plate lithography methods typically use cylindrically shaped masks (e.g. molds, stamps, photomasks, etc.) to transfer desired patterns onto rigid or flexible substrates. A desired pattern can be transferred onto a substrate using, for example, imprinting methods (e.g. nanoimprint lithography), the selective transfer of materials (e.g. micro- or nano-contact printing, decal transfer lithography, etc.), or exposure methods (e.g. optical contact lithography, near field lithography, etc.). Some advanced types of such cylindrical masks use soft polymers as patterned layers laminated on a cylinder's outer surface. Unfortunately, lamination of a layer on a cylindrical surface creates a seam line where the edges of the lamination layer meet. This can create an undesirable image feature at the seam when the pattern is repeatably transferred to a substrate by using the cylindrical mask.
[0013] In addition to fabricating a mask having a seamless polymer layer, it would be desirable to fabricate polymer layers with smooth surfaces that are thick and uniform for use in subsequent rolling lithography fabrication methods.
[0014] Patterned substrates and structured coatings have attractive properties for a variety of applications, including architectural glass, information displays, solar panels, and more. For example, nanostructured coatings can provide desirable antireflection characteristics for architectural glass. Current methods of patterning substrates, including methods such as electron beam lithography, photolithography, interference lithography, and other methods, are often too costly for practical use in the manufacture of patterned substrates or structured coatings in applications requiring larger areas, especially those having areas of 200 cm 2 or more.
[0015] As such, there is a need in the art for large area patterned layers and low cost methods of manufacturing the same. It is within this context that a need for the present invention arises.
[0016] Nanostructuring is necessary for many present applications and industries and for new technologies and future advanced products. Improvements in efficiency can be achieved for current applications in areas such as solar cells and LEDs, and in next generation data storage devices, for example and not by way of limitation.
[0017] Nanostructured substrates may be fabricated using techniques such as e-beam direct writing, Deep UV lithography, nanosphere lithography, nanoimprint lithography, near-field phase shift lithography, and plasmonic lithography, for example.
[0018] Earlier authors have suggested a method of nanopatterning large areas of rigid and flexible substrate materials based on near-field optical lithography described in International Patent Application Publication No. WO2009094009 and U.S. Pat. No. 8,182,982, which are both incorporated herein in their entirety. According to such methods, a rotatable mask is used to image a radiation-sensitive material. Typically the rotatable mask comprises a cylinder or cone with a mask pattern formed on its surface. The mask rolls with respect to the radiation sensitive material (e.g., photoresist) as radiation passes through the mask pattern to the radiation sensitive material. For this reason, the technique is sometimes referred to as “rolling mask” lithography.
[0019] This nanopatterning technique may make use of Near-Field photolithography, where the mask used to pattern the substrate is in contact with the substrate. Near-Field photolithography implementations of this method may make use of an elastomeric phase-shifting mask, or may employ surface plasmon technology, where the rotating mask surface includes metal nano holes or nanoparticles. In one implementation such a mask may be a near-field phase-shift mask.
[0020] Near-field phase shift lithography involves exposure of a radiation-sensitive material layer to ultraviolet (UV) light that passes through an elastomeric phase mask while the mask is in conformal contact with a radiation-sensitive material. Bringing an elastomeric phase mask into contact with a thin layer of radiation-sensitive material causes the radiation-sensitive material to “wet” the surface of the contact surface of the mask. Passing UV light through the mask while it is in contact with the radiation-sensitive material exposes the radiation-sensitive material to the distribution of light intensity that develops at the surface of the mask.
[0021] In some implementations, a phase mask may be formed with a depth of relief that is designed to modulate the phase of the transmitted light by π radians. As a result of the phase modulation, a local null in the intensity appears at step edges in the relief pattern formed on the mask. When a positive radiation-sensitive material is used, exposure through such a mask, followed by development, yields a line of radiation-sensitive material with a width equal to the characteristic width of the null in intensity. For 365 nm (Near UV) light in combination with a conventional radiation-sensitive material, the width of the null in intensity is approximately 100 nm. A polydimethylsiloxane (PDMS) mask can be used to form a conformal, atomic scale contact with a layer of radiation-sensitive material. This contact is established spontaneously upon contact, without applied pressure. Generalized adhesion forces guide this process and provide a simple and convenient method of aligning the mask in angle and position in the direction normal to the radiation-sensitive material surface, to establish perfect contact. There is no physical gap with respect to the radiation-sensitive material. PDMS is transparent to UV light with wavelengths greater than 300 nm. Passing light from a mercury lamp (where the main spectral lines are at 355-365 nm) through the PDMS while it is in conformal contact with a layer of radiation-sensitive material exposes the radiation-sensitive material to the intensity distribution that forms at the mask.
[0022] Another implementation of the rotating mask may include surface plasmon technology in which a metal layer or film is laminated or deposited onto the outer surface of the rotatable mask. The metal layer or film has a specific series of through nanoholes. In another embodiment of surface plasmon technology, a layer of metal nanoparticles is deposited on the transparent rotatable mask's outer surface, to achieve the surface plasmons by enhanced nanopatterning.
[0023] The abovementioned applications may each utilize a rotatable mask. The rotatable masks may be manufactured with the aid of a master mold (fabricated using one of known nanolithography techniques, like e-beam, Deep UV, Interference and Nanoimprint lithographies). The rotatable masks may be made by molding a polymer material, curing the polymer to form a replica film, and finally laminating the replica film onto the surface of a cylinder. Unfortunately, this method unavoidably would create some “macro” stitching lines between pieces of polymer film (even if the master is very big and only one piece of polymer film is required to cover entire cylinder's surface one stitching line is still unavoidable). It is within this context that the present invention arises.
SUMMARY
[0024] According to aspects of the present disclosure, a cylindrical mask may be fabricated by patterning a master mold, forming a patterned polymer mask by casting liquid polymer on the master mold, and curing the liquid polymer. A portion of one end of the patterned polymer mask may be cutoff or the liquid polymer is not cast on a strip at an end of the master mold. The master mold and the patterned polymer mask may be rolled to form a laminate cylinder to form a gap on the patterned polymer mask. The laminate cylinder may be inserted into a casting cylinder with the substrate to the master mold in contact with the casting cylinder and the gap filled with additional liquid polymer, which can be cured to form a free standing polymer by removing the casting cylinder and separating the master mold from the laminate.
[0025] According to other aspects of the present disclosure a cylindrical mask may be fabricated using a hollow casting cylinder and a mask cylinder. The casting cylinder may have an inner diameter that is larger than the outer diameter of the mask cylinder. The casting and mask cylinders may be coaxially assembled and a liquid polymer inserted in a space surrounding the mask cylinder between the inner surface of the casting cylinder and the outer surface of the mask cylinder. After curing the liquid polymer, the casting cylinder may be removed.
[0026] According to other aspects, a substrate may be patterned by successively repeating imprinting the substrate with a master mask having a pattern, the pattern having a smaller area than the substrate until a desired area of the substrate is patterned. Each successive imprinting may overlap part of a previously imprinted portion of the substrate. Imprinting the substrate with the master mask may include (i) depositing a polymer precursor liquid; (ii) pressing the polymer precursor liquid between the master mask and the substrate; and (iii) curing the polymer precursor liquid. The resulting substrate may have a patterned layer with a plurality of imprints, and each boundary between the imprints includes an imprint overlapping a portion of another imprint.
[0027] Additional aspects of the present disclosure describe cylindrical molds that may be used to produce cylindrical masks for use in lithography. A structured porous layer may be deposited on an interior surface of a cylinder. A radiation-sensitive material may be deposited over the porous layer in order to fill pores formed in the layer. The radiation-sensitive material in the pores may be cured by exposing the cylinder with a light source. The uncured resist and porous layer may be removed, leaving behind posts on the cylinder's interior surface.
[0028] Further aspects of the present disclosure include a cylindrical master mold assembly having a cylindrical patterned component with a first diameter and a sacrificial casting component with a second diameter. The component with the smaller radius may be co-axially inserted into the interior of the component with the larger radius. Patterned features may be formed on the interior surface of the cylindrical patterned component that faces the sacrificial casting component. The sacrificial casting component may be removed once a cast polymer has been cured to allow the polymer to be released.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1A-1C depict generic cylinders that are labeled to help clarify descriptive language used in the description and claims of the present invention.
[0030] FIG. 2 depicts a mask cylinder assembled inside of a cylindrical cast according to embodiments of the present invention.
[0031] FIG. 3 is a flowchart of a method of fabricating a cylindrical mask according to embodiments of the present invention.
[0032] FIGS. 4A-4D illustrate an assembly apparatus according to embodiments of the present invention.
[0033] FIGS. 5A-5D are a process flow diagram depicting a method of fabricating a cylindrical mask according to embodiments of the present invention.
[0034] FIGS. 6A-6I are a process flow diagram depicting a method of fabricating a cylindrical mask having multiple layers of polymer as a compliant outer layer according to embodiments of the present invention.
[0035] FIG. 7 is a schematic diagram illustrating an example of printing a pattern using rolling mask nanolithography with a cylindrical mask fabricated in accordance with an embodiment of the present invention.
[0036] FIG. 8A is an overhead view of a cylindrical master mold assembly comprising a cylindrical patterned component with a sacrificial casting component co-axially inserted inside according to an aspect of the present disclosure.
[0037] FIG. 8B is a perspective view of a cylindrical master mold assembly shown in FIG. 2A .
[0038] FIG. 9 is a block diagram of instructions that describe a method for forming a cylindrical mask with cylindrical master mold assembly according to aspects of the present disclosure.
[0039] FIG. 10A is an overhead view of a cylindrical master mold assembly comprising a sacrificial casting component with a cylindrical patterned component co-axially inserted inside according to an aspect of the present disclosure.
[0040] FIG. 10B is a perspective view of the cylindrical master mold assembly shown in FIG. 4A .
[0041] FIGS. 10C-10E depict how the cylindrical mask may be removed from the cylindrical patterned component according to aspects of the present disclosure.
[0042] FIG. 11 a block diagram of instructions that describe a method for forming a cylindrical mask with cylindrical master mold assembly according to aspects of the present disclosure.
[0043] FIGS. 12A-12C depict cylindrical masks where a gas retainer is formed between the elastomeric cylinder and the rigid transparent cylinder according to aspects of the present disclosure.
[0044] FIG. 13A depicts a master mask according to an embodiment of the present invention.
[0045] FIG. 13B depicts a master mask being used to pattern a larger area substrate according to an embodiment of the present invention.
[0046] FIG. 13C depicts an individual imprint of larger area substrate using a master mask according to an embodiment of the present invention.
[0047] FIGS. 13D-13E depict micrographs of the resulting patterned substrate according to an embodiment of the present invention.
[0048] FIGS. 14A-14G depict a process flow of imprinting a large area substrate according to an embodiment of the present invention.
[0049] FIGS. 15A-15C depict examples of patterned large area substrates according to embodiments of the present invention.
[0050] FIG. 16 is an overhead view of a cylinder master mold with protrusions extending out from the interior surface according to an aspect of the present disclosure.
[0051] FIGS. 17A-17G are schematic diagrams that show the process of forming the master mold according to aspects of the present disclosure.
[0052] FIGS. 18A-18D are schematic diagrams that show the process of forming the master mold according to additional aspects of the present disclosure that utilize an epitaxial seed layer.
[0053] FIGS. 19A, 19B, 19B ′, and 19 C are schematic diagrams that show the process of forming the master mold according to additional aspects of the present disclosure that utilize self-assembled monomers formed on the interior of the master mold.
[0054] FIGS. 20A, 20B, 20B ′, and 20 C are schematic diagrams that show the process of forming the master mold according to additional aspects of the present disclosure that utilize self-assembled monomers formed on the exterior surface of the master mold.
[0055] FIGS. 21A-21G are schematic diagrams that depict a process flow of producing a free-standing mask using a rolled laminate according to various aspects of the present disclosure.
[0056] FIG. 22A is an overhead view of a cylindrical master mold assembly having a rolled laminate used in making a cylindrical mask according to various aspects of the present disclosure.
[0057] FIG. 22B is a perspective view of the cylindrical master mold assembly shown in FIG. 22A .
[0058] FIG. 23 is a process flow diagram depicting a method of fabricating a cylindrical polymer mask using a rolled laminate according to various aspects of the present disclosure.
[0059] FIG. 24A is an overhead view of a cylindrical master mold assembly used in making a multilayered cylindrical mask according to various aspects of the present disclosure.
[0060] FIG. 24B is an overhead view of the cylindrical master mold assembly shown in FIG. 24A .
[0061] FIG. 25 is a process flow diagram depicting a method of fabricating a multilayered cylindrical polymer mask according to various aspects of the present disclosure.
DETAILED DESCRIPTION
[0062] The following definitions of terms help to clarify and aid in the understanding of the descriptive terminology used in the description and claims of the present disclosure.
[0063] As used herein,
[0000] “opposing ends” of a component refers the opposite faces of a cylinder or other axially symmetric shape as shown in FIG. 1A .
“outer surface” of a component refers to the exterior surface on the sides of a cylinder or other axially symmetric shape as depicted in FIGS. 1A and 1B .
“inner surface” of a component refers to the interior surface on the inner sides of a hollow cylinder or other axially symmetric shape as depicted in FIG. 1B .
“outer radius/diameter” of a component refers to a radius/diameter of an outer surface of a cylinder or other axially symmetric shape as depicted in FIGS. 1A and 1B . Where a component's outer surface is of a shape that has radius/diameter that is not constant, such as with a cone or other axially symmetric shape, the outer radius/diameter may refer to any such radii/diameters, so long as they correspond to the outer surface.
“inner radius/diameter” of a component refers to a radius/diameter of an inner surface of a cylinder or other axially symmetric shape as depicted in FIG. 1B . Where a component's inner surface is of a shape that has radius/diameter that is not constant, such as with a cone or other axially symmetric shape, the inner radius/diameter may refer to any such radii/diameters, so long as they correspond to the inner surface.
“coaxially assembling” components means assembling the components so that they have the same axis of symmetry as depicted in FIG. 1C .
“mask cylinder” or “masking cylinder” refers to a cylindrical substrate for a cylindrical mask, onto the outer surface of which a compliant layer is formed.
“cast cylinder” or “casting cylinder” refers to a cylindrically shaped cast.
I. Casting Using Coaxial Components
[0064] Aspects of the disclosure of this SECTION I include methods and apparatus for making rotatable masks. Various other methods and apparatus are also included in this section. Casting/molding processes and coaxial casting components may be used to cast a compliant layer of a rotatable mask, which can provide benefits that may include minimizing or eliminating the presence of a seam in the rotatable mask. There may be various other advantages to implementations of this section.
[0065] It is further noted that this SECTION I has applicability to and can readily be implemented in various aspects of the remaining SECTIONS II-VI of this description, including but not limited to any such sections that may involve the use of coaxial casting components and assemblies for making rotatable masks. By way of example and not by way of limitation, various aspects of the disclosure of this SECTION I can readily be applied to implementations of SECTION II of this description, which involves the use of sacrificial casting components and coaxially assembling components for fabrication of rotatable masks.
[0066] In order to fabricate a cylindrical mask, polymer material can be used as a compliant outer layer of a cylindrical mask. In embodiments of the present invention, a casting process can be used to form a compliant outer layer by casting polymer on the outer surface of a mask cylinder to create a seamless outer layer. A casting process in embodiments of the present invention can involve coaxially assembling a casting cylinder and a mask cylinder and inserting a liquid polymer in the space in the cast surrounding the mask cylinder. The polymer is then cured and the casting cylinder is removed to create a seamless cylindrical mask that can be used to fabricate a variety of devices. The polymer layer of the cylindrical mask can be patterned to create a mask pattern that can be repeatably transferred to a substrate, e.g. by roll-to-roll lithography, roll-to-plate lithography, etc.
[0067] In embodiments of the present invention, a method of fabricating a cylindrical mask can include coaxially assembling a casting cylinder and a mask cylinder, inserting liquid polymer in the space between the casting and mask cylinders, curing the polymer, and removing the casting cylinder. The method can further include patterning the polymer, which can be an additional step after removing the casting cylinder, or which can be incorporated into the fabrication process by using a cylinder having a pattern on its surface so that the pattern is transferred to the polymer when it comes into contact with the cylinder's surface.
[0068] In embodiments of the present invention, assembling a casting cylinder around the mask cylinder can involve the use of an assembly apparatus that holds the mask and casting cylinders in place during the fabrication of the cylindrical mask. The assembly apparatus can be designed to preserve the coaxial alignment of the cylinders during the casting process, creating cylindrical space of uniform thickness around the mask cylinder that corresponds to the outer compliant layer of the cylindrical mask. The fixture can be designed to permit a liquid polymer material to be inserted into this space while the cylinders are assembled with the fixture.
[0069] In embodiments of the present invention, an assembly apparatus used to preserve the coaxial alignment of cylinders in the fabrication process can include a set of plates, with the plates held together at opposing ends of the cylinders by a pin. The plates can include grooves aligned with the sides of the cylinders, or other means, to hold the alignment of the cylinders in place. One of the plates can have holes, or other means, that permit a liquid polymer to be poured through it and into the space corresponding to the outer compliant layer of the cylindrical mask.
[0070] The casting fixtures may be removed by disassembly. For example, after the polymer between the cylinders has cured, the casting cylinder may be separated into two or more sections by cutting it lengthwise from its exterior surface down to the tube cured polymer without significant damage to the polymer or leaving a small amount of the casting cylinder material. The cut can be made by saw, chemical etching, or laser. The sections of casting cylinder may then be the separated from the cured polymer and from each other.
[0071] Embodiments of the present invention are capable of creating patterned cylindrical masks having uniform and seamless outer layers with ideal thickness and smoothness for the repeatable transfer of the mask's pattern onto substrates for the fabrication of various devices.
[0072] Turning now to FIG. 2 , an assembly 200 of a mask cylinder 202 surrounded by a casting cylinder 204 is depicted according to an embodiment of the present invention. The cylinders 202 and 204 are coaxially assembled to so that their axes 206 are aligned, thereby creating a cylindrical region 208 of uniform thickness around the mask cylinder which can define the shape of the outer polymer layer of the cylindrical mask. Cylinders 202 and 204 can be held in place using an assembly apparatus (not pictured) that aligns their axes and permits a liquid polymer to be inserted into cylindrical region 208 of the assembly, such as by pouring it through openings or holes in the apparatus. Polymer precursor can be inserted in the space 208 between the cylinders 202 and 204 . The polymer precursor may be in the form of a monomer, a polymer, a partially cross-linked polymer, or any mixture of thereof in a liquid or semi-liquid form. The polymer precursor can be cured to form the outer polymer layer of the cylindrical mask. The polymer may be patterned with a mask pattern in a variety of ways. For example, the inner surface of casting cylinder 204 may contain a mask pattern so that the outer surface of the polymer material matches the pattern on the inner surface of the casting cylinder 204 . As another example, the outer surface of the mask cylinder 202 may contain a mask pattern so that this pattern is transferred to the inner surface of the polymer after it is formed on the mask cylinder. As another example, the polymer material may be patterned after subsequent fabrication steps and removal of the casting cylinder 204 by patterning the outer surface of the polymer using various lithography methods. As another example, the pattern may also be patterned by some combination of the above.
[0073] Turning to FIG. 3 , a flowchart of fabricating a seamless cylindrical mask is depicted according to embodiments of the present invention. Fabricating a cylindrical mask 300 can include coaxially assembling the cylinders as indicated at 302 , which can involve assembling a casting cylinder and a mask cylinder so that the axis of both the casting cylinder and the mask cylinder are the same. The casting cylinder may be a hollow cylinder with an inner diameter that is larger than the outer diameter of the mask cylinder, such that a space is left between the cylinders. This difference in diameters can define the thickness of the outer compliant layer of the mask so that, where D cast is the inner diameter of the casting cylinder and D mask is the outer diameter of the mask cylinder, the thickness T of the compliant layer of the cylindrical mask will be
[0000]
T
=
D
cast
-
D
mask
2
,
[0000] or half the difference in diameters. The thickness T can be selected as desired for various application specific requirements by using cylinders having the required diameters corresponding to the equation above. Fabrication 300 can also include inserting polymer precursor as indicated at 304 into the space in the casting cylinder that surrounds the outer surface of the mask cylinder. Inserting the polymer precursor can be done, for example, by pouring a liquid or semi-liquid polymer precursor material in through the top of the assembled cylinders into the space between them. Inserting the polymer precursor may be done in other ways, so long as the polymer precursor material is introduced into the space between the cylinders. Preferably, the polymer should substantially fill this space. The method for fabricating a cylindrical mask 300 can also include curing the polymer precursor as indicated at 306 to form a polymer layer. Curing the polymer precursor may involve applying UV radiation, heat, or other curing treatment to the assembly to harden the polymer. Once the polymer is cured, the method 300 may further include removing the casting cylinder, as indicated at 308 , leaving behind a cylindrical mask having a compliant outer layer corresponding to the cured polymer. The method 300 may also include patterning the polymer, and this can be accomplished, for example, by patterning the outer surface of the compliant layer after the removing the cast or by using patterned cylinders in the fabrication process so that patterning the polymer is integrated into the other fabrication steps.
[0074] It is noted that although the casting cylinder is shown as being assembled outside and around the mask cylinder, the reverse configuration is also possible. In such an implementation, the outer surface of the casting cylinder could be patterned and a negative of the pattern on the outer surface of the casting cylinder would be transferred to a polymer material on the inside surface of the mask cylinder when the casting cylinder is removed.
[0075] It is noted that removing the casting cylinder can be performed in a variety of ways. By way of example and not by way of limitation, the casting cylinder can be cut using a saw, a laser, wet or dry etching, or other means. When cutting the casting cylinder, care should be taken not to damage the polymer layer underneath. If a laser is used to cut the casting cylinder, a special layer could be deposited on the inside surface of the casting cylinder to act as an etch stop layer, and this layer should be reflective to the light that is used to cut the casting cylinder material. Cutting can be performed using one or more cut lines to make it easier to subsequently peel off the casting cylinder from the polymer surface. Once the casting cylinder is cut, it can be peeled off of the polymer surface mechanically. By way of example and not by way of limitation, the casting cylinder may be etched away chemically using etching chemicals that do not also etch away the polymer or mask cylinder within. By way of example and not by way of limitation, the casting cylinder may be treated with a low friction coating or other release coating prior to assembly so that, after the curing the casting cylinder can be slid off the polymer surface. By way of example and not by way of limitation, if the casting cylinder's coefficient of thermal expansion is larger than the polymer's, the casting cylinder could be heated to expand the casting cylinder and slide it off (if the polymer can withstand such temperatures). By way of example and not by way of limitation, the casting cylinder may be treated with a uniform coating, which can be dissolved after curing the polymer, and the casting cylinder can be slid off the polymer surface. The casting cylinder may also be removed by other means, and such other means of removal are within the scope of the present invention. Accordingly, the scope of the present invention is not to be limited to any specific method of removal unless explicitly recited in the claims.
[0076] Turning to FIG. 4 , details of an example of an assembly apparatus according to embodiments of the present invention is depicted. In FIG. 4A , an entire assembly apparatus 400 is depicted that can be used to fabricate a seamless cylindrical mask according to embodiments of the present invention. Apparatus 400 can include plates 402 held together by a pin 406 . The plates 402 can be held together at opposing ends of the cylinders (not pictured), and pin 406 preferably lines up with the axes of the cylinders. By way of example, the first plate 402 a can be oriented as a top plate during assembly and the second plate 402 b can be oriented as a bottom plate. The first plate 402 a can further include holes to permit a polymer to be poured through it and into a space between the cylinders. The plates can also include grooves 410 that align with the placement of the sidewalls of the mask cylinder and casting cylinder to facilitate holding them in place.
[0077] FIG. 4C depicts a top view of a first plate 402 a according to an embodiment of the present invention. The placement of holes 408 can correspond to the space inside of the casting cylinder surrounding the mask cylinder. First grooves 410 a can be aligned with a mask cylinder 412 and second grooves 410 b can be aligned with a casting cylinder 414 during fabrication of a cylindrical mask in embodiments of the present invention, as shown in FIG. 4C . In the embodiment shown in FIGS. 4B-4C it can be seen that holes 408 are positioned between the grooves 410 a and 410 b where the surfaces of the mask cylinder 412 and casting cylinder 414 would line up, in order to better facilitate pouring the polymer precursor 416 into the space between the two cylinders. It is noted that holes 408 can be designed in any of a variety of shapes, patterns, numbers of holes, etc., that permit the polymer precursor 416 to be inserted through the assembly apparatus, and the holes shown in FIG. 4C are provided for illustration purposes only. It is further noted that although circular plates are generally depicted, other shapes may be used, and the plates shown in the figures are for illustration purposes only.
[0078] FIG. 4D depicts a plan view of plate 402 according to an embodiment of the present invention.
[0079] Plate 402 can include grooves 410 to enable the apparatus 400 to hold the cylinders in place during fabrication of a cylindrical mask. Plate 402 can include first grooves 410 a aligned with a mask cylinder and second grooves 410 b aligned with a casting cylinder during fabrication of a cylindrical mask in embodiments of the present invention. It is noted that grooves 410 can be designed in any of a variety of shapes and patterns depending on the cylinders used to fabricate the cylindrical mask, and the grooves shown in the figures are provided for descriptive purposes only. It is also noted that both a first plate 402 a and a second plate 402 b can have grooves for holding the alignment of the cylinders in place such as are shown in FIGS. 4A-4D .
[0080] Turning to FIGS. 5A-5D , a process flow of fabricating a cylindrical mask is depicted according to embodiments of the present invention. In FIG. 5A , a casting cylinder 504 is coaxially assembled around a mask cylinder 502 to create assembly 506 using an assembly apparatus that holds the cylinders in place and aligns their center axes. In FIG. 5A , the fixture includes a first plate 508 a , a second plate 508 b , and a pin 510 that can attach to the plates 508 to hold them together at opposing ends of cylinders 502 and 504 . The cylinders 502 and 504 can be made from a variety of materials, including, for example, glass, metal, polymer, or other materials.
[0081] The mask cylinder, 502 , is preferably made of a material that is transparent to UV or other radiation used in the photolithography process employing the Cylinder Mask. Examples of materials for the mask cylinder 502 include fused silica. The casting cylinder 504 is preferably made from a material that is dimensionally stable for successful casting and is also amenable to the removal process, e.g., as described above. The casting cylinder may be transparent to UV or other radiation, but does not have to be so configured in all embodiments.
[0082] The inner surface of the casting cylinder 504 may include a mask pattern that corresponds to a desired pattern for the outer surface of the cylindrical mask's compliant layer so that the polymer is patterned during the casting process depicted in FIG. 5 . Likewise, the outer surface of the mask cylinder 502 may include a mask pattern for the inner surface of the cylindrical mask's compliant layer. Alternatively, the surfaces of the cylinders 502 and 504 may have no patterns, and the outer surface of the polymer may be patterned by various lithography methods after the compliant layer is formed. In FIG. 5B , a liquid polymer 512 is inserted into the space between the cylinders, between the inner surface of the casting cylinder 504 and the outer surface of the mask cylinder 502 . By way of example, inserting polymer precursor 512 can be accomplished by pouring it on the top of the assembly 506 through the fixture, through openings 514 left in top plate 508 a and into a space inside of the casting cylinder that surrounds the mask cylinder. In FIG. 5C , the polymer is cured, e.g., by applying UV radiation, temperature treatment, or other curing means 516 to the assembly 506 . In FIG. 5D , the casting cylinder 504 is removed from the cured polymer 518 , leaving behind cylindrical mask 520 with the cured polymer 518 as a compliant outer layer. If patterned cylinders were not used in the fabrication process, the process of FIG. 5 can further include patterning the outer surface of the compliant outer layer 518 with a desired mask pattern after removing the casting cylinder 504 .
[0083] It is noted that a pattern should be formed on a surface of the polymer, preferably the outer surface for contact lithography, so that the cylindrical mask may be used to transfer a pattern onto a substrate. In embodiments of the present invention, the outer surface of the polymer may be patterned by a variety of means. In embodiments of the present invention, a mask pattern may applied to the inner surface of the casting cylinder prior to filling the cast with a liquid polymer, such that the mask pattern is transferred to the outer surface of the polymer during casting on the mask cylinder. In other embodiments, the outer surface of the polymer may be patterned after removal of the casting cylinder. Regardless of the method of patterning chosen, care should be taken to avoid stitching errors when forming the mask pattern so that this pattern is also seamless. Accordingly, it is preferable that cylindrical masks of embodiments of the present invention include not only a seamless compliant layer, but also a seamless pattern on a surface of the compliant layer.
[0084] It is noted that patterning the inner surface of the casting cylinder or the outer surface of the mask cylinder can be done using a variety of techniques according to embodiments of the present invention. For example, the inner or outer surface of a cylinder may be patterned by successively imprinting it with a smaller master mask, as described in SECTION III of this description and in commonly-assigned, co-pending application No. 61/641,650, (attorney docket no. RO-014-PR), filed May 2, 2012, the entire disclosure of which is herein incorporated by reference. As another example, a cylinder surface may be patterned using any of a variety of known techniques, including nanoimprint lithography, nanocontact printing, photolithography, etc. As another example, the cylinder surface can be patterned using an anodization process. This can be accomplished, for example, by using a casting cylinder made of aluminum. An aluminum surface for anodization may alternatively be provided, for example, by depositing an aluminum layer on a surface of a cylinder. A nanoporous surface can then be created on the aluminum surface using an anodization process. As another example, patterning the inner surface can be performed by self-assembly of nanoparticles or nanospheres. Nanoparticles or nanospheres can be deposited from suspension using dipping methods, spraying methods, or other methods. Upon drying, cylinder material can be etched using these nanoparticles or nanospheres as an etch mask, then removing or etching away such etch mask.
[0085] Patterning the polymer on the outer surface of the cylindrical mask, after removal of the casting cylinder, can be done using a variety of techniques according to embodiments of the present invention. For example, the outer surface of the polymer may be patterned by successively imprinting it with a smaller master mask, as described in SECTION III of this description and in commonly-assigned, co-pending application No. 61/641,650 (attorney docket no. RO-014-PR), mentioned above. As another example, the outer surface of the polymer may be patterned using any of a variety of known techniques, including nanoimprint lithography, nanocontact printing, photolithography, nanosphere lithography, self-assembly, interference lithography, anodic aluminum oxidation, and the like.
[0086] It is also noted that the compliant layer of the cylindrical mask is not limited to a single polymer layer, but can include multiple layers of polymer having different properties. Embodiments of the present invention can include forming a two layer polymer for the compliant outer layer of a cylindrical mask. The outermost layer of the two layer polymer can be a harder layer having a higher durability than a softer, innermost polymer layer, thereby allowing patterning of higher resolution or higher aspect ratio nanostructures than can be done with just a soft polymer layer. The inner surface of the casting cylinder can be pretreated with a release coating to facilitate its removal from the outermost polymer layer at the end of fabrication. Forming a two layer polymer can involve depositing liquid polymer of the outermost layer on an inner patterned surface of a casting cylinder. For a two-layer polymer, the outer surface may be patterned after removal of the casting cylinder (instead of patterning the inside of the casting cylinder), in the same manner as a single layer cushioning material. The hard polymer layer can then be cured, for example, by temperature treatment, UV radiation, or other means. After curing, the inner surface of this hard polymer layer can be surface treated to promote adhesion to the other, softer, innermost polymer layer. Surface treatment can be done, for example, by plasma treatment, corona discharge, deposition of adhesion coating, or other means. A softer, innermost polymer layer can then be formed in the same manner as described above for a single layer polymer. It is also noted that a multilayered cylindrical mask can be formed by successively repeating the casting process described herein by casting a new polymer layer on the outer surface of a previously manufactured polymer layer. In this case, a larger casting cylinder should be used each time, after the previous casting cylinder is removed, in order to leave space for the new polymer layer between the outer surface of the previously manufactured polymer layer and the inner surface of the new casting cylinder.
[0087] In embodiments that use two or more polymer layers it is desirable that the optical index of both the material covering the prior pattern and the prior pattern are index matched. Also, it is desirable that the photolithography tool that uses the resulting mask be configured to accommodate masks with increasing diameters.
[0088] Turning to FIG. 6 , a more detailed process flow for forming a cylindrical mask having a two-layer polymer as its outer compliant layer is depicted according to an embodiment of the present invention. By way of example, fabricating a cylindrical mask having a compliant outer layer that is a two layer polymer can include patterning the inner surface of a casting cylinder 602 , as depicted in FIG. 6A . The patterned inner surface can then be treated with a release coating 604 to facilitate subsequent release of the casting cylinder from the outer surface of the outermost polymer layer, as shown in FIG. 6B . In FIG. 6C , a liquid polymer material 606 is deposited on the inner surface of the casting cylinder to form the outermost layer of the multilayered compliant outer laminate.
[0089] The polymer may be deposited in accordance with any of a number of known methods. By way of example, and not by way of limitation, the polymer may be deposited by dipping, ultrasonic spraying, microjet or inkjet type dispensing, and possibly dipping combined with spinning.
[0090] Polymer material 606 can preferably be a harder polymer, such as h-PDMS as described in Truong, T. T., et al, Soft Lithography Using Acryloxy Perfluoropolyether Composite Stamps. Langmuir 2007, 23, (5), 2898-2905, the disclosure of which is herein incorporated by reference. Using a more durable outer layer can permit the patterning of higher resolution or higher aspect ratio nanostructures than can be done with a single layer of polymer as the outer laminate of a cylindrical mask. In FIG. 6D , the outermost polymer layer 606 is cured by UV radiation, temperature treatment, or other curing means 608 a . In FIG. 6E , curing can be followed by surface treatment of the inner surface of the outer polymer layer 606 to promote adhesion between the polymer layers, for example by plasma treatment, corona discharge, deposition of adhesion coating, or other means. In FIG. 6F , the casting cylinder 602 having the outer polymer layer 606 on its inner surface is assembled around a mask cylinder 610 using an assembly apparatus having plates 612 held together on opposing ends of the cylinders 602 and 610 by pin 614 . In FIG. 6G , liquid polymer 618 is inserted into the casting cylinder by pouring it through holes or openings 620 in the top plate 612 a of the apparatus. Liquid polymer 618 can correspond to an inner polymer layer, which can be softer than the outer polymer layer, and liquid polymer 618 is inserted in the space between the inner surface of the casting cylinder 602 and the outer surface of the mask cylinder, and more specifically between the inner surface of the outer polymer layer and the outer surface of the mask cylinder. In FIG. 6H , inner polymer layer 618 is cured by applying curing means 608 b , which can be UV radiation, heat, or other means, to the assembly 616 . In FIG. 6I , casting cylinder 602 is removed leaving behind cylindrical mask 622 having a compliant outer layer that includes inner polymer layer 618 and outer polymer layer 606 on the outer surface of a mask cylinder 610 . Cylindrical mask 622 has a patterned outer surface that corresponds to the mask pattern applied to the inner surface of the casting cylinder 602 in the step of FIG. 6A .
[0091] It is further noted that the thickness of the polymer layer(s) may vary according to various application specific requirements. The thickness of the polymer layer(s) may preferably be, but is not required to be, in the range of about 0.5 mm-5 mm. Where a two-layer polymer is used, a softer innermost layer may be relatively thick, for example in the range of about 0.5-5 mm, and the harder, outermost, patterned layer may be relatively thin, for example in the range of about 0.5-10 μm.
[0092] It is further noted that the polymer used to fabricate the cylindrical mask can be, for example, Polydimethylsiloxane (PDMS) materials, such as Sylgard® 184 of Dow Corning®, h-PDMS (“hard” PDMS), soft-PDMS gel, etc. Where two layers of polymer are used, the soft inner polymer may be a soft-PDMS gel and the outer layer can be Sylgard® 184, for example. As another example, the inner layer may be Sylgard® 184 and the outer layer may be h-PDMS. It is noted that a variety of other elastomeric and polymer materials can be used to fabricate a cylindrical mask and are within the scope of the present invention. Other possible polymers that may be used include optical adhesives, e.g., mercapto-ester based adhesives, a number of which are available from Norland products of Cranbury, N.J., perfluoropolyethers, or other UV curable or heat curable polymers.
[0093] It is also noted that the means used for curing polymer in embodiments of the present invention can depend on the type of polymer being cured, the cylinder material used, and other factors. For example, curing can be done thermally, with UV radiation, or other means.
[0094] It is further noted that those having ordinary skill in the art can conceive of various modifications to the design of an assembly apparatus or the method of preserving the alignment of cylinders in place without departing from the teachings of the present invention.
[0095] It is also noted that the present invention can be used to form various different patterns for various substrates and devices. Patterns can include features of having dimensions of different sizes and can preferably include micro or nanoscaled features, and more preferably have nanoscaled features.
[0096] Embodiments of the present invention may be used in conjunction with a type of lithography known as “rolling mask” nanolithography. An example of a “rolling mask” near-field nanolithography system is described, e.g., in commonly-assigned International Patent Application Publication Number WO2009094009, which is incorporated by reference herein. An example of such a system is shown in FIG. 7 . The “rolling mask” may be in the form of a glass (e.g. quartz) frame in the shape of hollow cylinder 711 , which contains a light source 712 . An elastomeric film 713 formed on the outer surface of the cylinder 711 as described above may have a nanopattern 714 fabricated in accordance with the desired pattern to be formed on a substrate 715 . The nanopattern 714 can be designed to implement phase-shift exposure, and in such case is fabricated as an array of nanogrooves, posts or columns, or may contain features of arbitrary shape.
[0097] By way of example, and not by way of limitation, the nanopattern 714 on the cylinder 711 may have features in the form of parallel lines having a linewidth of about 50 nanometers and a pitch of about 200 nanometers or greater. In general, the linewidth may be in a rage from about 1 nanometer to about 500 nanometers and pitch may range from about 10 nanometers to about 10 microns. Although examples are described herein in which the nanopattern 714 is in the form of regularly parallel lines, the nanopattern may alternatively be a regularly repeating two-dimensional pattern, having regularly-spaced and arbitrarily-shaped spots. Furthermore, the pattern features (lines or arbitrary shapes) may be irregularly spaced.
[0098] The nanopattern 714 on the cylinder 711 is brought into a contact with a photosensitive material 716 , such as a photoresist that is coated on a substrate 715 . The photosensitive material 716 is exposed to radiation from the light source 712 and the pattern 714 on the cylinder 711 is transferred to the photosensitive material 716 at the place where the nanopattern contacts the photosensitive material. The substrate 715 is translated as the cylinder rotates such that the nanopattern 714 remains in contact with the photosensitive material. Depending on the nature of the photosensitive material, portions of the pattern that are exposed to radiation may react with the radiation so that they become removable or non-removable.
[0099] By way of example, if the photosensitive material is a type of photoresist known as a positive resist, the portion of the material that is exposed to light becomes soluble to a developer and the portion of the material that is unexposed remains insoluble to the developer. By way of counterexample, if the photosensitive material is a type of photoresist known as a negative resist, the portion of the material that is exposed to light becomes insoluble to a developer and the unexposed portion of the material is dissolved by the photoresist.
[0100] In certain embodiments of the present invention, the photosensitive material 716 may be exposed by passing the substrate past the cylinder 711 two or more times. For sufficiently small values of the pitch and linewidth, the linear pattern of exposure resulting from one pass is unlikely to line up with each other. As a result, lines from one pass are likely to end up between lines of a previous pass. By careful choice of the pitch, linewidth, and number of passes it is possible to end up with a pattern of lines in the photosensitive material 716 that has a pitch smaller than the pitch of the lines in the pattern 714 on the cylinder 711 .
[0101] When patterning the polymer, care should be taken to avoid stitching errors in the pattern. Preferably, fabrication of a cylindrical mask in embodiments of the present invention also involves patterning a seamless pattern on a seamless polymer layer. This prevents a seam from being transmitted to a substrate when the cylindrical mask is used to repeatably pattern a substrate, both because the compliant outer layer itself is seamless, and because the pattern contained on a surface of the compliant layer is also seamless.
[0102] It is further noted that embodiments of the invention may be applied to fabrication of rolling masks that are axi-symmetric but not cylindrical, e.g., masks that are frusto-conical in shape. In such cases, a mask element and cast element may be co-axially aligned with plates held together by one or more pins. When co-axially assembled, the facing surfaces of the mask element and the cast element may have similar shapes and the same aspect ratio so that a space of substantially uniform thickness is defined between them.
II. Casting Using Sacrificial Components
[0103] Aspects of the disclosure of this SECTION II include methods and apparatus for making rotatable masks using sacrificial casting components. Various other methods and apparatus are also included in this section. Sacrificial casting components in accordance with aspects of this section may be used in conjunction with patterned casting components in order to cast a compliant layer for a rotatable mask, which can provide benefits that may include preserving a patterned casting component for future use without damage to a pattern on its surface. There may be various other advantages to implementations of this section.
[0104] It is further noted that this SECTION II has applicability to and can readily be implemented in various aspects of the remaining SECTIONS I and III-VI of this description, including but not limited to any such sections that may involve the use of coaxial casting components and assemblies for making rotatable masks. By way of example and not by way of limitation, various aspects of the disclosure of this SECTION II can readily be implemented in SECTION VI of this description, which involves the use of coaxially assembling components for fabrication of multilayered rotatable masks.
[0105] Aspects of the present disclosure describe various patterned component assemblies and methods for fabricating near-field optical lithography masks for “Rolling mask” lithography with the patterned component assemblies. In rolling mask lithography, a cylindrical mask is coated with a polymer, which is patterned with desired features in order to obtain a mask for phase-shift lithography or plasmonic printing. The features that are patterned into the polymer may be patterned through the use of the patterned component assemblies described in the present application. The pattern component may include patterned features that range in size from about 1 nanometer to about 100 microns, preferably from about 10 nanometers to about 1 micron, more preferably from about 50 nanometers to about 500 nanometers. The cylindrical mask may be used to print features ranging in size from about 1 nanometer to about 1000 nanometers, preferably about 10 nanometers to about 500 nanometers, more preferably about 50 nanometers to about 200 nanometer
[0106] A first aspect of the present disclosure describes a cylindrical master mold assembly comprised of a cylindrical patterned component that has a first diameter and a sacrificial casting component that has a second diameter. The second diameter may be smaller than the first diameter. Patterned features may be formed on the interior surface of the cylindrical patterned component and the sacrificial casting component may be inserted co-axially into the interior of the cylindrical patterned component. A polymer material may then fill the gap between the patterned component and the sacrificial casting component in order to form the cylindrical mask. The sacrificial casting component may be removed once the polymer has been cured. According to certain aspects of the present disclosure, the sacrificial casting component may be fractured in order to allow the cylindrical mask to be removed. Additionally, certain aspects of the present disclosure also provide for the sacrificial casting component to be deformed in order to allow the cylindrical mask to be removed.
[0107] According to an additional aspect of the present disclosure a cylindrical master mold assembly may have a cylindrical patterned component that has a first diameter, and a sacrificial casting component that has a second diameter. The second diameter may be larger than the first diameter. The patterned component may have patterned features formed on its exterior surface. The patterned component may be inserted co-axially into the sacrificial casting component. A polymer may then fill the gap between the patterned component and the sacrificial casting component. Once the polymer has cured, the sacrificial casting component may be broken away, leaving the cylindrical mask on the patterned component. The cylindrical mask may then be peeled off of the patterned component.
[0108] According to a further aspect, a cylindrical mask may comprise a cylindrical elastomer component with an inner radius and a rigid transparent cylindrical component having an outer radius. A gas retainer is configured to retain a volume of gas between an inner surface of the elastomer component and an outer surface of the rigid transparent cylindrical component. The elastomer component has a major surface with a nanopattern formed in the major surface. The outer radius of the rigid transparent component is sized to fit within the cylindrical elastomer component.
[0109] In some implementations, the gas retainer may include two seals. Each seal seals a corresponding end of the volume of gas. Such seals may be in the form of O-rings or gaskets.
[0110] In some implementations, the volume of gas may be retained by a bladder disposed between the major surface of the elastomer component and the major surface of the rigid transparent cylindrical component.
[0111] In some implementations, the major surface of the cylindrical elastomeric component on which the nanopattern is formed is an outer cylindrical surface.
[0112] The authors have described a “Rolling mask” near-field nanolithography system earlier in International Patent Application Publication Number WO2009094009, which is incorporated herein by reference. One of the embodiments is show in FIG. 7 . The “rolling mask” consists of a glass (e.g., fused silica) frame in the shape of hollow cylinder 711 , which contains a light source 712 . An elastomeric cylindrical rolling mask 713 laminated on the outer surface of the cylinder 711 has a nanopattern 714 fabricated in accordance with the desired pattern. The rolling mask 713 is brought into a contact with a substrate 715 coated with radiation-sensitive material 716 .
[0113] A nanopattern 714 can be designed to implement phase-shift exposure, and in such case is fabricated as an array of nanogrooves, posts or columns, or may contain features of arbitrary shape. Alternatively, nanopattern can be fabricated as an array or pattern of nanometallic islands for plasmonic printing. The nanopattern on the rolling mask can have features ranging in size from about 1 nanometer to about 100 microns, preferably from about 10 nanometers to about 1 micron, more preferably from about 50 nanometers to about 500 nanometers. The rolling mask can be used to print features ranging in size from about 1 nanometer to about 1000 nanometers, preferably about 10 nanometers to about 500 nanometers, more preferably about 50 nanometers to about 200 nanometers.
[0114] The nanopattern 714 on the rolling mask 713 may be manufactured with the use of a cylindrical master mold assembly. Aspects of the present disclosure describe the cylindrical master mold assembly and methods for forming the nanopattern on the rolling mask 713 .
[0115] FIG. 8A is an overhead view of a master mold assembly 800 . The master mold assembly 800 comprises a cylindrical patterned component 820 and sacrificial casting component 830 . The cylindrical patterned component 820 may have a first radius R 1 and the sacrificial casting component 830 may have a second radius R 2 . According to a first aspect of the present disclosure, R 1 may be greater than R 2 in order to allow for the sacrificial casting component 830 to be co-axially inserted into the interior of the cylindrical patterned component 820 with a space 840 between them.
[0116] The patterned component 820 may be made from a material that is transparent to optical radiation, such as infrared, visible, and/or ultraviolet wavelengths. By way of example, and not by way of limitation, the cylinder may be a glass such as fused silica. It is noted that fused silica is commonly referred to as “quartz” by those in the semiconductor fabrication industry. Although quartz is common parlance, “fused silica” is a better term. Technically, quartz is crystalline and fused silica is amorphous. As may be seen in FIG. 8B , the interior surface of the patterned component 820 may be patterned with the desired pattern 825 that will be used to form the nanopattern 714 on the cylindrical mask 713 . By way of example, and not by way of limitation, the pattern 825 may be formed with the use of structured porous mask or a self-assembled monolayer (SAM) mask in conjunction with photolithography techniques described in SECTION IV of this description and in commonly owned U.S. patent application Ser. No. 13/756,348, entitled “CYLINDRICAL MASTER MOLD AND METHOD OF FABRICATION” (Attorney Docket No. RO-018-US) filed Jan. 31, 2013, and incorporated by reference herein in its entirety.
[0117] The sacrificial casting component 830 should be able to be removed after the cylindrical rolling mask 713 has been cured without damaging the nanopattern 714 . According to aspects of the present disclosure, the sacrificial casting component 830 may be a thin walled cylinder that is formed from a material that is easily fractured. By way of example, and not by way of limitation, the material may be glass, sugar, or an aromatic hydrocarbon resin, such as Piccotex™ or an aromatic styrene hydrocarbon resin, such as Piccolastic™. Piccotex™ and Piccolastic™ are trademarks of Eastman Chemical Company of Kingsport, Tenn. By way of example, and not by way of limitation, the sacrificial casting component 830 may be approximately 1 to 10 mm thick, or in any thickness range encompassed therein, e.g., 2 to 4 mm thick. The nanopattern 714 of the cylindrical mask 713 is not located on the surface of the sacrificial casting component 830 , and therefore the nanopattern 714 is not susceptible to damage during the removal. According to additional aspects of the present disclosure, the sacrificial casting component 830 may be made from a material that is dissolved by a solvent that does not harm the patterend component 820 or the cylindrical mask 713 . By way of example, a suitable dissolvable material may be a sugar based material and the solvent may be water. Dissolving the sacrificial casting component 830 instead of fracturing may provide additional protection to the nanopattern 714 .
[0118] According to yet additional aspects of the present disclosure, the casting component 830 may be a thin walled sealed cylinder made from malleable material such as plastic or aluminum. Instead of fracturing the sacrificial casting component 830 , the sealed component may be removed by collapsing the component by evacuating the air from inside the cylinder. According to yet another aspect of the present disclosure, the sacrificial casting component 830 may be a pneumatic cylinder made of an elastic material. Examples of elastic materials that may be suitable for a pneumatic cylinder include, but are not limited to plastic, polyethylene, polytetrafluoroethylene (PTFE), which is sold under the name Teflon®, which is a registered trademark of E. I. du Pont de Nemours and Company of Wilmington, Del. During the molding process, the sacrificial casting component 830 may be inflated to form a cylinder and once the cylindrical mask 713 has cured, the casting component 830 may be deflated in order to be removed without damaging the cylindrical mask. In some implementations, such a pneumatic cylinder may be reusable or disposable depending, e.g., on whether it is relatively inexpensive to make and easy to clean.
[0119] As in FIG. 9 , aspects of the present disclosure describe a process 900 that may use cylindrical master mold assemblies 800 to form cylindrical masks 713 . First, at 960 a sacrificial casting component 830 may be co-axially inserted into a cylindrical patterned component 820 . Then, the space 840 between the sacrificial casting component 830 and the cylindrical patterned component 820 is filled with a liquid precursor that, when cured, forms an elastomeric material at 961 . By way of example, and not by way of limitation, the material may be polydimethylsiloxane (PDMS).
[0120] Next, at 962 the liquid precursor is cured to form the elastomeric material that will serve as the cylindrical mask 713 . By way of example, the curing process may require exposure to optical radiation. The radiation source may be located co-axially within the master mold assembly 800 when the sacrificial casting component 830 is transparent to the wavelengths of radiation required to cure the liquid precursor. Alternatively, the radiation source may be located outside of the master mold assembly 800 and the exposure may be made through the cylindrical patterned component 820 . Once the cylindrical mask 713 has cured, the sacrificial casting component 830 may be removed at 962 . By way of example, and not by way of limitation, the casting component 830 may be removed by fracturing, dissolving, deflating, or collapsing.
[0121] FIG. 10A is an overhead view of a cylindrical master mold assembly 1000 according to an additional aspect of the present disclosure. As shown, the cylindrical patterned component 1020 may have a first radius R 1 and the sacrificial casting component 1030 may have a second radius R 2 that is larger than R 1 . The cylindrical master mold assembly 1000 is formed by co-axially inserting the cylindrical patterned component 1020 inside of the sacrificial casting component 1030 leaving an empty space 1040 between the two components.
[0122] The patterned component 1020 may be made from a material that is transparent to optical radiation, such as infrared, visible and/or ultraviolet wavelengths. By way of example, and not by way of limitation, the cylinder may be a glass, such as quartz. As shown in the perspective view in FIG. 10B , a pattern 1025 is formed on the exterior surface of the cylindrical patterned component 1020 . By way of example, and not by way of limitation, the pattern 1025 may be formed through the use of nanolithography techniques such as, but not limited to e-beam direct writing, Deep UV lithography, nanosphere lithography, nanoimprint lithography, near-field phase shift lithography, and plasmonic lithography.
[0123] The sacrificial casting component 1030 may be removed after the cylindrical rolling mask 713 has been cured without damaging the nanopattern 714 . According to aspects of the present disclosure, the sacrificial casting component 1030 may be a thin walled cylinder that is formed from a material that is easily fractured. By way of example, and not by way of limitation, the material may be glass. The nanopattern 714 of the cylindrical mask 713 is not located on the surface of the sacrificial casting component 1030 , and therefore the nanopattern 714 is not susceptible to damage during the removal. According to additional aspects of the present disclosure, the sacrificial casting component 1030 may be made from a material that is dissolved by a solvent that does not harm the patterend component 1020 or the cylindrical mask 713 . By way of example, a suitable dissolvable material may be a sugar based material and the solvent may be water. Dissolving the sacrificial casting component 1030 instead of fracturing may provide additional protection to the nanopattern 714 .
[0124] After the sacrificial casting component 1030 has been removed, the cylindrical mask 713 remains on the patterned component 1020 as shown in FIG. 10C . In order to remove the cylindrical mask 713 from the patterned component 1020 the cylindrical mask 713 may be peeled back against itself. Starting from one end of the patterned component 1020 , the cylindrical mask is pulled back over itself in a direction parallel to the axis of the patterned component 1020 , such that the interior surface where the nanopattern 714 was formed is revealed. FIG. 10D depicts the removal process at a point where the cylindrical mask 713 has been partially removed. In order to fold back on itself during the removal process, the cylindrical mask 713 should be relatively thin, e.g., 4 millimeters thick or thinner. As such, the difference between the first and second radii should preferably be 4 millimeters or less. Once the entire cylindrical mask 713 has been removed from the patterned component 1020 , it will have been turned completely inside out, revealing the nanopattern 714 on the exterior surface as shown in FIG. 10E .
[0125] As in FIG. 11 , aspects of the present disclosure describe a process 1100 that may use cylindrical master mold assemblies 1000 to form cylindrical masks 713 . First, at 1160 a cylindrical patterned component 1020 is co-axially inserted into a sacrificial casting component 1030 . Then, the space 1040 between the sacrificial casting component 1030 and the cylindrical patterned component 1020 is filled with a liquid precursor that, when cured, forms an elastomeric material at 1161 . By way of example, and not by way of limitation, the material may be polydimethylsiloxane (PDMS).
[0126] Next, at 1162 the liquid precursor is cured to form the elastomeric material that will serve as the cylindrical mask 713 . By way of example, the curing process may require exposure to optical radiation. The radiation source may be located co-axially within the master mold assembly 1000 . Alternatively, the radiation source may be located outside of the master mold assembly 1000 and the exposure may be made through the sacrificial casting component 1030 if the casting component 1030 is transparent to the wavelengths of radiation required to cure the liquid precursor. Once the cylindrical mask 713 has cured, the sacrificial casting component 1030 may be removed at 1163 . By way of example, and not by way of limitation, the sacrificial casting component 1030 may be removed by fracturing and/or dissolving. Finally, at 1164 the cylindrical mask is pulled back over itself in a direction parallel to the axis of the patterned component 1020 , such that the interior surface where the nanopattern 714 was formed is revealed.
[0127] FIG. 12A depicts a cylindrical mask 1200 according to an additional aspect of the present disclosure. Cylindrical mask 1200 is substantially similar to the cylindrical mask depicted in FIG. 7 , with the addition of a gas retainer 1218 located between the elastomeric rolling mask 1213 and the rigid hollow cylinder 1211 . By way of example, and not by way of limitation, the elastomeric rolling mask 1213 may have a patterned surface 1214 and may be a made in substantially the same manner as described in processes 900 or 1100 . The rigid hollow cylinder may also be transparent to optical radiation. By way of example, and not by way of limitation, the hollow cylinder may be a glass such as fused silica. A light source 1212 may be placed inside hollow cylinder 1211 . The gas retainer 1218 retains a volume of gas 1217 between the outer surface of the cylinder 1211 and the inner surface of the elastomeric mask 1213 . The gas retainer 1218 may be pressurized in order to provide an additional tunable source of compliance for the elastomeric rolling mask 1213 . By way of example, and not by way of limitation, the gas retainer 1218 may be formed by a pair of seals or by an inflatable bladder.
[0128] FIG. 12B is a cross sectional view along the line 6 - 6 shown in FIG. 12A of a cylindrical rolling mask 1201 that depicts an aspect of the present disclosure where the gas retainer 1218 is formed by pair of seals 1218 S . Each seal 1218 S may be a hollow cylinder, ring, or torus-like shape, such as, but not limited to an O-ring or gasket. The seals 1218 S may be made of a suitable elastomer material. The elastomeric mask 1213 may then be spaced apart from the rigid hollow cylinder 1211 at each end by a seal 1218 S . The inner radius of the elastomeric mask 1213 can be chosen such that the volume of gas 1217 bounded by the interior surface of the elastomeric mask 1213 , the seals 1218 S and the rigid outer surface of the rigid hollow cylinder 1211 may be pressurized. When the volume of gas 1217 is pressurized, the elastomeric mask 1213 may be spaced away from the outer surface of the rigid hollow cylinder 1211 by the pressure of the volume of gas 1217 retained between the inner surface of the elastomeric mask 1213 and the outer surface of the cylinder 1211 . The cylinder 1211 may optionally include grooves sized and shaped to receive the seals 1218 S and facilitate retaining the seals when the gas in the volume is pressurized.
[0129] FIG. 12C is a cross sectional view along the line 6 - 6 shown in FIG. 12A of a cylindrical rolling mask 1202 that depicts an aspect of the present disclosure where the gas retainer 1218 is formed by a bladder 1218 B . The bladder 1218 B may be cylindrical in shape and positioned between the rigid hollow cylinder 1211 and the elastomeric mask 1213 . When volume of gas 1217 within the bladder 1218 B is pressurized, the bladder 1218 B supports the elastomeric mask 1213 above the outer surface of the rigid hollow cylinder 1211 .
III. Patterning a Larger Area Substrate Using Successive Imprints
[0130] Aspects of the disclosure of this SECTION III include methods and apparatus for patterning a larger area master mask using a successive imprinting scheme with a smaller area master mask. Various other methods and apparatus are also included in this section. Successive imprints can be used to pattern a relatively large area substrate for a variety purposes, which can provide benefits that may include minimizing or eliminating the visibility or effect of seams between imprints. Various other advantages of this section will be apparent upon reading this section.
[0131] It is further noted that this SECTION III has applicability to and can readily be implemented in various aspects of the remaining SECTIONS I, II, and IV-VI of this description, including but not limited to any such sections that may involve the use of patterned components. By way of example and not by way of limitation, various aspects of the disclosure of this SECTION III can readily be applied to implementations of SECTION V of this description, which involves the use of a rolled laminate having a pattern for making a rotatable mask.
[0132] In embodiments of the present invention, a small master mask having a desired pattern can be used to inexpensively pattern a large area substrate. A small master can be successively imprinted onto a large area substrate using a polymer precursor liquid that is polymerized or cured. An array of imprints is formed by the successive imprinting scheme, where each successive imprint overlaps part of a previous imprint so that there is no un-patterned interstitial space. In this manner, the desired pattern of the master is replicated generating a macroscopically continuous pattern whose dimension is limited only by the size of the substrate. The successive imprinting scheme results in a large area substrate having a patterned layer or structured coating with a nearly invisible boundary between the individual imprints, or replicas, of the master.
[0133] In embodiments of the present invention, a method of patterning a large area substrate can include imprinting the substrate with a master mask having a pattern, wherein the pattern has a smaller area than the substrate area to be patterned. The method can further include successively repeating the imprinting process until a desired area of the substrate is patterned. Each successive imprint can include depositing a polymer precursor liquid, pressing the polymer precursor liquid between the master mask and the substrate, and polymerizing or curing the polymer precursor liquid such that it becomes a solid material.
[0134] It is noted that in embodiments of the present invention, substrates to be patterned can be a variety of shapes, sizes, materials, etc., but should generally be larger than the master mask used to successively imprint the substrate. Master masks can also be a variety of shapes, sizes, materials, etc., and can have patterns of a variety of shapes and sizes, but should generally be smaller than the substrate area to be patterned. In embodiments of the present invention, substrates to be patterned can have a variety of characteristics and, for example, can be flexible, rigid, flat or curved. Likewise, master masks can have a variety of characteristics and, for example, can be flexible or rigid.
[0135] In embodiments of the present invention, desired patterns can include features of a variety of different sizes, shapes, and arrangements. A variety of physical or other properties can be imparted to a substrate by using patterns having various features depending on application specific requirements.
[0136] Turning to FIGS. 13A-13C , a master mask and a method of fabricating a larger area substrate with a master mask are depicted according to embodiments of the present invention.
[0137] In FIG. 13A , master mask 1302 having pattern 1304 is depicted, which can be used to imprint a larger area substrate by repeatedly imprinting the larger area substrate with the master mask 1302 . While the master mask 1302 depicted in FIG. 13A is has a circular shape, and its pattern 1304 covers a rectangular area of the mask, it is noted that both the master mask 1302 and the master pattern 1304 can be a variety of different shapes and sizes in embodiments of the present invention, and the master pattern 1304 can cover all or part of the area of the master mask 1302 . Master pattern 1304 should correspond to the desired pattern for a large area substrate, and can vary depending on various application specific requirements. For example, the master pattern 1304 can include a uniform array of posts or uniform array of holes as used in many structured coating applications. It is noted that in structured coating embodiments of the present invention, an array of posts is preferred over an array of holes as experiments have shown that a post array master pattern leads to a lower visibility of seams at the boundaries of successive imprints. By way of example FIGS. 13D and 13E provide a micrograph of an array of posts formed in a photoresist by exposure to UV light through a pattern in a cylindrical mask and developing the exposed resist.
[0138] FIG. 13B depicts a master mask 1302 used to imprint a larger area substrate 1306 . Master mask 1302 can be used to repeatedly imprint a portion of the substrate 1306 until a desired area of the substrate is patterned. Each successive imprint with the master mask 1302 can overlap part of the previously imprinted portion 1308 of the substrate 1306 , and the pattern of the imprint 1308 that is left on the substrate 1306 corresponds to the mask pattern 1304 .
[0139] FIG. 13C depicts an individual imprint during a successively repeating imprint scheme according to embodiments of the present invention. In FIG. 13C , it can be seen that a polymer precursor liquid 1310 spreads as the liquid is pressed between a master mask 1302 and a substrate 1306 . By way of example and not by way of limitation, the polymer precursor liquid 1310 may be a monomer, a polymer, a partially cross-linked polymer, or any mixture of thereof. An imprinting scheme as depicted in FIGS. 13A-13C according to embodiments of the present invention should preferably include a method of controlling the spread of the polymer precursor liquid in order to minimize the presence of air bubbles, fill the features of the master pattern, and prevent the liquid from flowing outside of the border of the mask pattern contained on the master mask and onto an open area of a previously cured imprint. There are a variety of methods that can be used to control the spread of the polymer precursor liquid during each imprint. In the example shown in FIG. 13C , controlling the spread of polymer precursor liquid 1310 includes maintaining a continuous line of pressure along a line of contact 1312 between the master mask 1302 and the substrate 1306 . Mechanical pressure can be applied along the contact line 1312 to force the spread of polymer precursor liquid 1310 towards an open area of the substrate 1306 in the direction of pressure 1314 and maintain the liquid 1310 within the boundary of the master pattern 1304 . In some embodiments, maintaining a continuous line of pressure can be better facilitated by using a flexible substrate for substrate 1306 , thereby creating a more clearly defined line of contact 1312 between the master mask 1302 and the substrate 1306 . In other embodiments, maintaining a continuous line of pressure of can be facilitated by using a flexible mask for master mask 1302 . In still other embodiments, maintaining a continuous line of pressure can be facilitated by using a curved mask or curved substrate for mask 1302 or substrate 1306 , respectively. In still other embodiments, the spread of polymer precursor liquid 1310 can be controlled by other means.
[0140] Turning to FIGS. 14A-14G , a process flow of a method of patterning a substrate is depicted according to an embodiment of the present invention. In FIGS. 14A-14G , master mask 1402 is used to pattern the substrate 1404 , and master mask 1402 should be smaller than substrate 1404 . More specifically, the area of the master pattern 1406 of the mask 1402 should be smaller than the area to be patterned on the substrate 1404 , and the master pattern 1406 should correspond to the desired pattern of the larger area substrate 1404 . Master mask 1402 is used to pattern the substrate 1404 by successively imprinting the substrate 1404 until it is fully patterned, or at least until a desired area of the substrate 1404 is patterned.
[0141] In FIG. 14A , a polymer precursor liquid 1408 is deposited onto a substrate 1404 , and the polymer precursor liquid 1408 corresponds to the patterned layer or structured coating of the large area substrate 1404 . It is noted that polymer precursor liquid 1408 can be deposited in a variety of ways. For example, in the embodiment shown in FIGS. 14A-14G , polymer precursor liquid 1408 is deposited onto the substrate 1404 as discrete drops for each successive imprint. In other embodiments, polymer precursor liquid 1408 can be deposited onto the master mask 1402 . In still other embodiments, polymer precursor liquid 1408 can be deposited continuously through the patterning process as opposed to discrete drops before each imprint. It is noted that the material used for polymer precursor liquid 1408 can vary depending on various application specific requirements. The amount of polymer precursor liquid 1408 that is deposited can vary depending of various application specific requirements, including, for example, the desired thickness of the layer, the size of the desired imprint area, and the feature depth and pitch of the desired pattern to be formed.
[0142] In FIG. 14B , polymer precursor liquid 1408 is pressed between the master mask 1402 and the substrate 1404 in order to transfer the master pattern 1406 to polymer precursor liquid 1408 . Pressing the polymer precursor liquid as shown in FIG. 14B preferably should be done with care and using a method of controlling the spread of the polymer precursor liquid in order to minimize air bubbles, fill the features of the master pattern 1406 , and maintain the polymer precursor liquid 1408 within the area of the master pattern 1406 during the imprint process. Controlling the spread of the polymer precursor liquid can include, for example, maintaining a continuous line of pressure as depicted in FIG. 13C and described above. In FIG. 14A-14G , pressing the polymer precursor liquid 1408 between the master mask 1402 and the substrate 1404 is depicted as pressing the master mask 1402 against the substrate 1404 , but it is noted that the present invention is not limited to such embodiments. In embodiments of the present invention, pressing the polymer precursor liquid between the master mask 1402 and the substrate 1404 can involve pressing the substrate 1404 against the master mask 1402 . In other embodiments, pressing the polymer precursor liquid 1408 between the master mask 1402 and the substrate 1404 can be done by still other means, such as by pressing both the master mask 1402 and the substrate 1404 against each other simultaneously.
[0143] In FIG. 14C , the patterned polymer precursor liquid is cured or polymerized using curing means 1410 , which can be a source of UV radiation, heat, or other equivalent means depending on the nature of the polymer precursor liquid, specifically, the mechanism by which the polymer precursor liquid can be cured or polymerized. After the polymer precursor liquid is cured or polymerized, master mask 1402 can be removed and a successive imprint can be formed.
[0144] In FIG. 14D , a successive imprint is formed that overlaps part of the previously imprinted and cured portion 1412 by again depositing liquid polymer precursor liquid 1408 . To minimize the visibility of the border between successive imprints, part of the polymer precursor liquid should be deposited onto part of the previously imprinted portion 1412 of the substrate 1404 , within the area of where the master pattern 1406 will overlap the previously imprinted portion, as depicted in FIG. 14D .
[0145] In FIG. 14E , the polymer precursor liquid 1408 is again pressed between the master mask 1402 and the substrate 1404 to transfer the master pattern 1406 onto the polymer precursor liquid and imprint another portion of the substrate 1404 . Care should be taken to control the flow of the polymer precursor liquid 1408 and prevent it from flowing onto a portion of the previously cured portion 1412 of the substrate that is beyond the boundary of the master pattern 1406 .
[0146] In FIG. 14F , the polymer precursor liquid is again cured using curing means 1410 , after curing the master mask 1402 can be removed, leaving behind a larger patterned portion 1412 on the substrate 1404 , as shown in FIG. 14G . This process can be successively repeated until the substrate 1404 is fully patterned, or until a desired area of the substrate 1404 is patterned.
[0147] After each portion of the substrate is imprinted, the un-patterned area of the substrate 1404 may be cleaned as desired by wet cleaning or dry cleaning processes. By way of example, wet cleaning processes may include use of chemicals e.g., common organic solvents such as acetone, physical removal of the particles and/or plasma cleaning. The selective cleaning process of the un-patterned area may require the use of shadow mask (not shown) to prevent any damage of patterned area. To prevent any contaminations or damages of the patterned area, the patterned area may optionally be selectively treated with hydrophobic silane. In other words, the patterned area may be made hydrophobic and the un-patterend area may be made hydrophilic. By way of example, the cleaning process may include hydrophobic surface treatment (of both the patterned and un-patterned area) followed by plasma treatment of the un-patterned area and the region of the patterned area that will be overlapped during the next imprint.
[0148] In an additional embodiment a checkered board type pattern of patterned and unpatented areas are generated on a substrate and treated with hydrophobic silane. Then the substrate is plasma treated using shadow mask so that only the unpattern surface of the substrate and the surface where the new imprint is to be overlapped are exposed to plasma. In the second step all the un-patterned area of the substrate is then imprinted.
[0149] In FIGS. 15A-15C , a variety of patterned substrates imprinted according to the methods described herein are depicted. It is noted that embodiments of the present invention include master mask and master patterns having a variety of different shapes and sizes, and successive imprints can be arranged in a variety of different arrays and arrangements. Likewise the larger substrate that is patterned with the master mask can be a variety of shapes, sizes, etc.
[0150] The embodiments shown in FIG. 15A-15C depict two dimensional arrays and arrangements, although it is noted that the present invention is not limited to such embodiments. Embodiments of the present invention can include imprint schemes that involve two dimensional arrays of successive imprints, one-dimensional arrays of successive imprints, or other arrangements of successive imprints in the imprinting scheme. However, it is noted that two dimensional arrays and arrangements are preferred in some embodiments of the present invention as it can minimize the visibility of seams between successive imprints.
[0151] In FIG. 15A , a substrate 1502 a patterned with a two-dimensional rectangular array of successive imprints 1504 a is depicted. The pattern on the substrate 1502 a can be virtually continuous and uniform at the macro-level as the visibility of seam lines 1506 a at the borders between successive imprints is minimal. In various applications of the present invention, the presence of seam lines can have little to no effect on the desired functional properties of the patterned or structured substrate.
[0152] In FIG. 15B , substrate 1502 b is depicted having a two-dimensional hexagonal array of successive imprints 1504 b according to embodiments of the present invention.
[0153] In FIG. 15C , substrate 1502 c is depicted having a randomized two-dimensional arrangement of successive imprints 1504 c creating randomized seam lines 1506 c between successive imprints. Randomizing the imprints can provide certain benefits in some applications of the present invention, and the visibility of the seams 1506 b can be minimized on the macro level by providing a randomized pattern instead of a regular array. In FIG. 15C , substrate 1502 c depicted is fully patterned edge to edge, according to some embodiments of the present invention, and amount of surface area that can be pattern is limited only by the size of the substrate chosen.
[0154] It is noted that increasing the amount of seam lines, up to a certain limit, can minimize the visibility of such seam lines while providing minimal or no detraction from desired properties created by the pattern or structure imprinted onto the substrate. For example, in an architectural glass implementation of an embodiment of the present invention, a nanostructured coating can be applied to provide antireflection properties on the glass using an imprinting scheme as described herein. Increasing the number of seam lines can minimize their visibility at the macro level while still providing the required anti-reflection properties provided by the nanostructure. This can be contrasted with known methods that attempt to minimize seam lines by patterning the entire large area with a single uniform layer at a very high cost.
[0155] In embodiments of the present invention, substrates to be patterned can be a variety of shapes and sizes, but should generally be larger than the master mask used to successively imprint the substrate. In some embodiments, substrates to be patterned can have square shapes, rectangular shapes, or other shapes. In some embodiments, substrates can be flat, curved, or have other three-dimensional surfaces. In some embodiments, substrates can have dimensions of 150 mm×150 mm or greater. In some embodiments, substrates to be patterned can have dimensions of 400 mm×1000 mm and larger. Embodiments of the present invention can also include substrates having smaller areas than those mentioned, although it is believed that embodiments of the present invention have particular applicability to embodiments involving larger area substrates, such as those having areas of 200 cm 2 or more.
[0156] In embodiments of the present invention, master masks can be a variety of shapes and sizes, and can have patterns of a variety of shapes and sizes, but should generally be smaller than the substrate area to be patterned. In some embodiments, master masks can have dimensions of 10 mm to 50 mm and areas of 100 mm 2 to 2500 mm 2 . In other embodiments, the master masks can have dimensions and areas outside of those mentioned above, although it is noted that preferred embodiments include square masks having dimensions of 10 mm×10 mm to 50 mm×50 mm. In some embodiments, master masks can have circular shapes, rectangular shapes, or other shapes. In some embodiments, a master pattern can cover an entire surface of a master mask or part of a surface of a master mask.
[0157] In embodiments of the present invention, desired patterns can include features of a variety of different sizes, shapes, and arrangements. In some embodiments, desired patterns can include micro-scale features, nano-scale features, or other scale features. In some embodiments, features can include features having dimensions in the range of 100 nm to 400 nm. In some embodiments, features can be shaped as holes, posts, or other shapes. In some embodiments, features can be arranged in a regular array or a randomized pattern.
[0158] It is noted that the figures are primarily depicted with respect to flat substrates and patterning flat surfaces, but the present invention is not so limited. Embodiments of the present invention can be used to pattern curved surfaces or substrates having a variety of other shapes but successively imprinting such surfaces with a smaller area master mask as described herein.
[0159] It is noted that embodiments of the present invention can be used to pattern very large area substrates with patterns having small feature dimensions on the micro-scale or nano-scale. More specifically, embodiments of the present invention can be used to provide nanostructured coatings on large surface areas having nano-scaled feature dimensions. More specifically, embodiments of the present invention can be used to provide nanostructured coatings have arrays of features, e.g., posts or holes, having a characteristic dimension (CD) of 1 nanometers (nm) to 1000 nm, a pitch of 1.1 times the CD to 10 times the CD, and a depth of 10 nm to 10000 nm. A preferred embodiment of the present invention includes a CD between 50 nm and 400 nm, a pitch of 2 times the CD, and a depth ranging from 100 nm to 1000 nm. The CD is generally a dimension of the features along a direction perpendicular to the depth. Examples of CD include a width or diameter for circular or nearly circular shaped features.
[0160] In embodiments of the present invention, the master mask pattern can be created by a variety of methods. For example, the master mask can be patterned by electron beam lithography, photolithography, interference lithography, nanosphere lithography, nanoimprint lithography, self-assembly, anodic alumina oxidation, or other means.
[0161] It is noted that substrates in embodiments of the present invention can be a variety of types of materials and types of substrates. For example, substrates can be made of plastic films, glass, semiconductors, metals, other smooth substrates, or other materials.
[0162] It is noted that substrates patterned according to embodiments of the present invention can include a surfaces for a variety of different applications. For example, embodiments of the present invention can be used for solar panels, information displays, architectural glass, and a variety of other applications. For example, embodiments of the present invention can be used for nanostructured solar cells, light absorption enhancement layers, anti-reflective coatings, self-cleaning coatings, TCO for solar cells and displays, nanostructured thermoelectric cells, low-E glass, anti-icing coatings, anti-glare coatings, efficient display color filters, FPD wire grid polarizers, LED light extraction layers, nanopatterned magnetic media, nanopatterned water filtration media, nanoparticles for drug deliver, ultrasensitive sensors, nanoelectrodes for batteries, and other applications. It is also noted that patterned substrates according to embodiments of the present invention can be used as large masks that are themselves used to pattern other large surfaces such as those mentioned above.
[0163] It is noted that uniform patterns are typically used in various structured coating applications. While using successive imprints as described herein may create non-uniformities at the borders between imprints, the entire area patterned can appear macroscopically continuous and desired properties imparted by the pattern will be unaffected or very minimally affected by the borders.
[0164] It is also noted that while embodiments of the present invention have primarily been described with respect to two-dimensional arrays of imprints, the present invention is not limited to such embodiments. For example, embodiments of the present invention can include one dimensional arrays of imprints and other imprinting schemes that involve imprints that repeats in only one dimension. However, it is noted that two dimensional arrays and imprinting schemes that repeat in two dimensions are preferred as this minimizes this visibility of the borders between imprints.
IV. Patterning a Surface of a Casting Component
[0165] Aspects of the disclosure of this SECTION IV include methods and apparatus for patterning a surface of a casting component, including various exposure and epitaxial techniques. Various other methods and apparatus are also included in this section. Patterning a casting surface in accordance with aspects of this section can be used conjunction with a casting process of a compliant layer for a rotatable mask, which can provide benefits that may include minimizing or eliminating any seams in the pattern of the rotatable mask. Various other advantages of this section will be apparent upon reading this section.
[0166] It is further noted that this SECTION IV has applicability to and can readily be implemented in various aspects of the remaining SECTIONS I-III, V, and VI of this description, including but not limited to any such sections that may involve the use of patterned casting components. By way of example and not by way of limitation, various aspects of the disclosure of this SECTION IV can readily be applied to implementations of SECTION VI of this description, which involves the use of a patterned casting component for forming a multilayered rotatable mask.
[0167] Aspects of the present disclosure describe a mold and methods for manufacturing molds that may be useful in the fabrication of lithography masks, for example, near-field optical lithography masks for “Rolling mask” lithography, or masks for nanoimprint lithography. In rolling mask lithography, a cylindrical mask is coated with a polymer, which is patterned with desired features in order to obtain a mask for phase-shift lithography or plasmonic printing. The features that are patterned into the polymer may be patterned through the use of the molds described in the present application. The molds may include patterned features that protrude from an interior surface of an optically transparent cylinder. The protruding features may range in size from about 1 nanometer to about 100 microns, preferably from about 10 nanometers to about 1 micron, more preferably from about 50 nanometers to about 500 nanometers. The mask can be used to print features ranging in size from about 1 nanometer to about 1000 nanometers, preferably about 10 nanometers to about 500 nanometers, more preferably about 50 nanometers to about 200 nanometer
[0168] An aspect of the present disclosure describes a mold that may be made with a porous mask. A layer of structured porous material may be deposited or grown on an interior surface of an optically transparent cylinder. One example of grown porous material is a porous alumina fabricated using anodization of aluminum layer (Anodized Aluminum Oxide—AAO). The interior of the cylinder may then be coated with a radiation-sensitive material. The radiation-sensitive material will fill in the pores that are formed in the structured porous material. The radiation-sensitive material may then be developed by exposing the exterior of the cylinder with a light source. Exposure from the exterior allows the radiation-sensitive material that has filled the pores to be cured without curing the remaining resist. The uncured resist and the porous mask material may be removed, thereby forming a mold that has posts extruding from its interior surface.
[0169] According to an additional aspect of the present disclosure, an epitaxial layer may be grown on the interior surface of the cylinder. Structured porous material may then be deposited or otherwise formed on the epitaxial layer. The epitaxial layer may then be grown using the pores in the porous layer as a guide. The epitaxial layer may be grown to a thickness greater than the structured porous layer, or the structured porous layer may be etched back to leave the epitaxial post behind. According to certain aspects of the present disclosure, the epitaxial material may be a semiconductor material. Each of the epitaxial posts may be configured to be a light emitting diode (LED). The LED posts may further be configured to be individually addressable such that radiation may be selectively produced by individual posts.
[0170] According to an additional aspect of the present disclosure, the mold may be formed with a self-assembled monolayer of nanospheres. The monolayer may be formed over a layer of radiation-sensitive material that has been formed on the interior surface of a cylinder. The radiation-sensitive material may then be exposed by a light source located in the interior of the cylinder. The self-assembled monolayer masks portions of the radiation-sensitive material during exposure. The exposed regions may then be removed by a developer. The radiation-sensitive material that was shielded by the self-assembled monolayer may then be cured and in order to form posts that are made from a glass-like substance.
[0171] According to an additional aspect of the present disclosure, a self-assembled monolayer of nanospheres formed may comprise quantum dots. The quantum dots may be formed over a layer of radiation-sensitive material that has been formed on the interior surface of a cylinder. The quantum dots may be used to expose the radiation-sensitive material directly below each dot. As such, there may be no need for an external light source. The developer may then remove the unexposed portions of the radiation-sensitive material. The exposed portions of the radiation-sensitive material may then be cured to form a glass-like substance.
[0172] According to an additional aspect of the present disclosure, a self-assembled monolayer of nanospheres may be formed on the exterior surface of the cylinder and a radiation-sensitive material may be formed on the interior surface of the cylinder. A light source positioned outside of the cylinder may be used to produce the radiation that exposes the radiation-sensitive material. The nanospheres may mask portions of the radiation-sensitive material from the radiation. The exposed portions may be removed with a developer, thereby leaving behind posts. The posts may be cured to produce a glass-like material.
[0173] According to an additional embodiment of the present invention the self-assembled monolayer may comprise quantum dots. The quantum dots may be formed on an exterior surface of a cylinder. The quantum dots may be used to expose portions of a radiation-sensitive material that has be formed on an interior surface of the cylinder. As such, there may be no need for an external light source. The developer may then remove the unexposed portions of the radiation-sensitive material. The exposed portions of the radiation-sensitive material may then be cured to form a glass-like substance. The radiation-sensitive material that has been formed on the interior surface of a cylinder.
[0174] A “Rolling mask” near-field nanolithography system has been described in International Patent Application Publication Number WO2009094009, which has been incorporated herein by reference. One of the embodiments is shown in FIG. 7 . The “rolling mask” consists of glass (e.g., fused silica) frame in the shape of hollow cylinder 711 , which contains a light source 712 . An elastomeric film 713 laminated on the outer surface of the cylinder 711 has a nanopattern 714 fabricated in accordance with the desired pattern. The rolling mask is brought into a contact with a substrate 715 coated with radiation-sensitive material 716 .
[0175] A nanopattern 714 can be designed to implement phase-shift exposure, and in such case is fabricated as an array of nanogrooves, posts or columns, or may contain features of arbitrary shape. Alternatively, nanopattern can be fabricated as an array or pattern of nanometallic islands for plasmonic printing. The nanopattern on the rolling mask can have features ranging in size from about 1 nanometer to about 100 microns, preferably from about 10 nanometers to about 1 micron, more preferably from about 50 nanometers to about 500 nanometers. The rolling mask can be used to print features ranging in size from about 1 nanometer to about 1000 nanometers, preferably about 10 nanometers to about 500 nanometers, more preferably about 50 nanometers to about 200 nanometers.
[0176] The nanopattern 714 on the cylinder 711 may be manufactured with the use of a master mold. Aspects of the present disclosure describe the master methods and methods for forming a mold that has features that will form a nanopattern 714 that has holes or depressions. In order to form holes or depressions in the rolling mask, the master mold may have protrusions, such as posts.
[0177] FIG. 16 is an overhead view of a master mold 1600 according to an aspect of the present disclosure. The master mold 1600 is a hollow cylinder 1620 that has an exterior surface 1621 and an interior surface 1622 . The cylinder 1620 may be made from a material that is transparent to radiation that is in the visible and/or ultraviolet wavelengths. By way of example, and not by way of limitation, the cylinder may be a glass such as fused silica. The master mold 1600 has protrusions 1633 that extend outwards from the interior surface 1622 .
[0178] FIGS. 17A-17G are cross sectional views of the master mold 1600 as seen along the line 3 - 3 shown in FIG. 16 . Each figure depicts a processing step used in the fabrication of the master mold 1600 according to aspects of the present disclosure.
[0179] FIG. 17A is a depiction of the master mold after a structured porous layer 1730 on an interior surface of the cylinder 1720 . By way of example, and not by way of limitation, the, cylinder 1720 may be made of a transparent material, such as fused silica. It is noted that fused silica is commonly referred to as “quartz” by those in the semiconductor fabrication industry. Although quartz is common parlance, “fused silica” is a better term. Technically, quartz is crystalline and fused silica is amorphous. The structured porous layer 1730 contains a high density of cylindrical pores 1729 that are aligned perpendicular to the surface on which the structured porous layer is disposed. The size and density of the pores 1729 may be in any range suitable for the desired features of the mask pattern, e.g., as discussed above with respect to FIG. 16 . By way of Example and not by way of limitation, the nanostructured porous layer 1730 may be a layer of anodic aluminum oxide (AAO) that has been formed on an interior surface 1722 of the cylinder 1720 . AAO is a self-organized nanostructured material containing a high density of cylindrical pores that are aligned perpendicular to the surface on which the AAO layer is disposed. The AAO may be formed by depositing a layer of aluminum on the interior surface 1722 of a cylinder 1720 made of fused silica and then anodizing the aluminum layer. Alternatively, the cylinder 1720 may be made completely from aluminum, and then internal or external surfaces of such a cylinder could be anodized to form a porous surface. Anodizing the aluminum layer may be done by passing an electric current through an electrolyte (often an acid) with the aluminum layer acting as a positive electrode (anode).
[0180] In alternative implementations, the nanostructured porous layer may be fabricated using a self-assembled monolayer or by direct writing techniques, such as laser ablation or ion beam lithography.
[0181] As shown in FIG. 17A , the pores 1729 may not penetrate through the entire depth of the layer 1730 . If the pores 1729 do not extend through the structured porous layer 1730 down to the interior surface 1722 of the cylinder, the material of the structured porous layer may be etched back with an etch process. If the etch process is isotropic, the original size of the pores 1729 must be made small enough to account for growth during the etching process. For example, if the final diameter of the pores is desired to be 300 nm, and the original diameter of the pores 1729 is 50 nm, then the isotropic etch must remove 125 nm of porous material in order to enlarge the diameter of the pores 1729 to 300 nm. Additionally, if the etch process is isotropic, only 125 nm of material may be removed from the bottom of the pore in order to extend the pore to the interior surface 1722 of the cylinder. If more material needs to be removed in order to reach the interior surface 1722 , then the diameter of the pores 1729 may become larger than desired. FIG. 17B depicts the enlarged pores 1729 that completely extend through the nanostructured porous layer 1730 .
[0182] After the pores 1729 have been etched to the proper dimensions and depths, a radiation-sensitive material 1731 may be deposited over the nanostructured porous layer 1730 and the exposed portions of the interior surface 1722 , as shown in FIG. 17C . By way of example, and not by way of limitation, the radiation-sensitive material 1731 may be deposited by dipping, spraying, rolling, or any combination thereof. By way of example, and not by way of limitation, the radiation-sensitive material 1731 may be a photoresist or a UV curable polymer. Examples of suitable photoresists include commercially available formulations such as TOK iP4300 or Shipley 1800 series from Dow Chemical Co. Examples of suitable UV-curable materials include UV polymerizable adhesives for polymers and glass. Additionally, the radiation-sensitive material 1731 contains silicon and other constituents that enable the material to be annealed after it has cured in order to produce a glass-like material. Other constituents that may be used to help form the glass-like material include Oxygen and Silicon. The radiation-sensitive material 1731 may be a solid film, or it may be a liquid layer as long as it does not flow excessively during exposure.
[0183] Next, FIG. 17D shows the cured material 1732 in the pores 1729 . The radiation-sensitive material 1731 is cured by exposure to a radiation 1723 from a radiation source (not shown). By way of example, and not by way of limitation, the radiation 1723 may be produced by a radiation source that produces ultraviolet light or the radiation 1723 may be produced by a radiation source that produces light in the visible spectrum. The radiation source may be located outside of the cylinder and may emit radiation 1723 that passes through the wall of the cylinder 1720 . The illumination through the cylinder 1720 limits the exposure to the material 1731 deposited in the AAO pores 1729 . Additionally, the exposure cures the material 1731 to a depth of roughly twice the exposure wavelength. By way of example, when an ultraviolet wavelength is used for curing, then the cured material 1732 may have a thickness of approximately 600 nm. The curing sensitivity of the radiation-sensitive material 1731 must be sufficiently high to allow the radiation-sensitive material inside the pores 1729 to be cured before the material 1731 above the pores 1729 is cured. Also, the depth of the pores 1729 may be greater than the projected thickness of the cured material 1732 in order to prevent exposure of the radiation-sensitive material 1731 directly above the pores 1729 .
[0184] FIG. 17E shows the master mold 1700 after the excess radiation-sensitive material has been removed after the cured material 1732 has been formed. The remaining unexposed radiation-sensitive material 1721 may be removed with a developer or other solvent. Thereafter, as shown in FIG. 17F , the cured material 1732 is annealed in order to form a glass-like material 1733 . Finally, once the annealing is completed, the AAO layer 1730 may be selectively etched away with a wet etching process. FIG. 17G depicts the final structure of the master mold 1700 . The glass-like material 1733 protrudes from the interior surface 1722 of the cylinder 1720 .
[0185] According to an additional aspect of the present disclosure, the protrusions may be formed through an epitaxial growth process. FIG. 18A is an overhead view of a master mold 1800 . The master mold 1800 is a hollow cylinder 1820 that has an exterior surface 1821 and an interior surface 1822 . The cylinder 1820 may be made from a material that is transparent to radiation that is in the visible and/or ultraviolet wavelengths. By way of example, and not by way of limitation, the cylinder may be a glass such as fused silica. An epitaxial seed layer 1824 may be formed on the interior surface 1822 . By way of example, and not by way of limitation, the epitaxial seed layer 1824 may be a semiconductor material such as silicon or gallium arsenide (GaAs). The master mold 1800 has protrusions 1833 that extend outwards from the epitaxial seed layer 1824 . The protrusions may be the same material as the epitaxial seed layer 1824 . FIGS. 18B-18D are cross-sectional views of the master mold 1800 along the line 4 - 4 .
[0186] FIG. 18B is a depiction of a structured porous layer 1830 that is deposited over the epitaxial seed layer 1824 . As shown in FIG. 18B , the pores 1829 might not penetrate through the entire depth of the structured porous layer 1830 .
[0187] When the pores 1829 do not extend through the structured porous layer 1830 down to the epitaxial seed layer 1824 , then the structured porous layer material may be etched back with an etch process. If the etch process is isotropic, the original size of the pores 1829 must be made small enough to account for growth during the etching process. For example, if the final diameter of the pores is desired to be 300 nm, and the original diameter of the pores 1829 is 50 nm, then the isotropic etch must remove 125 nm of aluminum in order to enlarge the diameter of the pores 1829 to 300 nm. Additionally, if the etchant is an isotropic etchant, only 125 nm of material may be removed from the bottom of the pore in order to extend the pore to the epitaxial seed layer 1824 . If more material needs to be removed in order to reach the epitaxial seed layer 1824 , then the diameter of the pores 1829 may become larger than desired. FIG. 18C depicts the enlarged pores 1829 that completely extend through the structured porous layer 1830 .
[0188] Once the pores 1829 have been completed, the protrusions 1833 may be formed with an epitaxial growth process, such as, but not limited to vapor-phase epitaxy (VPE). The growth of the protrusions 1833 is guided by the pores 1829 in the structured porous layer 1830 . The protrusions 1833 may be grown to a height that allows them to protrude beyond the structured porous layer 1830 . However, the protrusions 1833 may be shorter than the structured porous layer 1830 , if the structured porous layer will be subsequently etched back in order to expose the protrusions 1833 .
[0189] According to aspects of the present disclosure, protrusion 1833 formed through epitaxial growth of a semiconductor material may further be configured to be LEDs. Each of the protrusions 1833 may be individually addressable such that each may be controlled to emit light as desired. This is beneficial for use as a master mold, because the molding process no longer requires an external light source. The protrusions 1833 may function as a physical mold, and may be used to cure the photomask that is being molded at the same time. Further, the ability to control individual protrusions allows for a single master mold to be utilized in order to form multiple different patterns by selecting which protrusions will also cure the material in the photomask.
[0190] According to yet another additional aspect of the present disclosure, a self-assembled monolayer may be used as a mask to pattern the protrusions 1933 in a master mold 1900 . FIGS. 19A-19C are cross-sectional views of a master mold 1900 at different processing steps during the mold's fabrication. FIG. 19A depicts the formation of a self-assembled monolayer (SAM) 1940 formed over a radiation-sensitive material 1931 on the interior surface 1922 of the cylinder 1920 . By way of example, and not by way of limitation, the SAM 1940 may be formed from metal nanospheres, or quantum dots. By way of example, and not by way of limitation, the radiation-sensitive material 1931 may be photoresist or a UV curable polymer. Additionally, the radiation-sensitive material 1931 contains silicon and other constituents that enable the material to be annealed in order to produce a glass-like material.
[0191] Next, at FIG. 19B , the radiation-sensitive material 1931 is exposed with radiation 1923 from a radiation source (not shown). Plasmonic lithography may be utilized, e.g., if the SAM 1940 comprises metal nanospheres. The metal nanospheres may be used as plasmonic mask antennae. The portions of the radiation-sensitive material 1931 that are exposed to radiation may become soluble to a developer solvent used to develop the radiation-sensitive material. The portion of the radiation-sensitive material that is unexposed 1932 may remain insoluble to the developer solvent. It is noted that alternative aspects of the present disclosure include use of a reverse tone process in which portions of the radiation-sensitive material 1931 that are exposed to radiation become insoluble to a developer and portions of the radiation-sensitive material that are not so exposed remain soluble to the developer. Alternative aspects of the present disclosure where the SAM 1940 comprises quantum dots may not need an additional light source to expose the radiation-sensitive material 1931 . As shown in FIG. 19B ′ the quantum dots in the SAM 1940 may be activated in order to expose the radiation-sensitive material 1931 . When the exposure is made by the quantum dots, the radiation-sensitive material may be cured by the exposure. The non-exposed portions of the radiation-sensitive material 1931 may therefore be removed by the developer. Finally, in FIG. 19C the protrusions 1933 are annealed in order to convert the cured radiation-sensitive material 1932 into glass-like material.
[0192] Alternative aspects of the present disclosure include implementations in which the mask itself is made with light emitting diodes (LEDs). Such a mask may be implemented, e.g., using a polymer mask with an array of holes smaller than features that are desired to be printed, with a corresponding layer of LEDs above it. A specific subset of the LEDs may be turned on to define the pattern to be printed.
[0193] According to an additional aspect of the present disclosure, a SAM 2040 may be formed on the exterior surface 2021 of the cylinder 2020 as show in FIG. 20A . The SAM 2040 may be substantially similar to the SAM 1940 . The formation of a SAM 2040 on the exterior surface allows for the light used for the exposure to originate from outside of the cylinder 2020 as shown in FIG. 20B . In FIG. 20B , the radiation-sensitive material 2031 may be exposed with radiation 2023 that is emitted by a radiation source (not shown) that is located outside of the cylinder 2020 . Alternatively, if the SAM 2040 comprises quantum dots, then the radiation source that produces the radiation 2023 may be omitted, and the quantum dots may be used to expose the radiation-sensitive material 2031 instead, as shown in FIG. 20B ′. Finally, FIG. 20C shows the removal of the non-exposed radiation-sensitive material, and the annealing of the protrusions 2033 to form the glass-like material.
V. Forming a Rotatable Mask Using a Rolled Laminate
[0194] Aspects of the disclosure of this SECTION V include methods and apparatus for forming a rotatable mask using a rolled laminate. Various other methods and apparatus are also included in this section. Forming a rotatable mask in accordance with aspects of this section can be used to form a compliant layer for a rotatable mask, which can provide benefits that may include minimizing or eliminating any seams layer where the edges of the laminate meet. There may be various other advantages to implementations of this section.
[0195] It is further noted that this SECTION V has applicability to and can readily be implemented in various aspects of the remaining SECTIONS I-IV and VI of this description, including but not limited to any such sections that may involve a compliant layer rolled onto the outer surface of a rotatable substrate. By way of example and not by way of limitation, various aspects of the disclosure of this SECTION V can readily be applied to implementations of SECTION I of this description, which involves the use of coaxial assemblies to form a cast a compliant layer.
[0196] A process flow diagram depicting a method 2100 for fabricating a free standing polymer mask according to various aspects of the present disclosure is depicted in FIGS. 21A-21G . Various steps in the process flow FIGS. 21A-21G may be performed in accordance with various aspects of the above description for forming a free standing polymer mask.
[0197] The method 2100 may include first making a patterned master mold/mask 2112 (alternatively referred to herein as a first master mask or “submaster” mask because it may be a mask used to pattern to a main rotatable mask for a subsequent fabrication process), as depicted in FIGS. 21A and 21B . The patterned submaster may be created by patterning a substrate 2105 to create the pattern 2110 on the submaster 2112 . Patterning the submaster mask may be accomplished in a variety of ways. In some implementations, patterning the substrate to create a submaster mask utilizes involves successively overlapping cured imprints on a substrate 2105 with a smaller mask to create a quasi-seamless pattern 2110 for the submaster mask, according to various aspects of the disclosure of SECTION III of this description. In yet further implementations, the submaster may be patterned using any of a variety of known techniques, such as, e.g., nanoimprint lithography, nanocontact printing, photolithography, etc.
[0198] The method 2100 may further include casting an elastomeric material 2115 (alternatively referred to herein as a polymer precursor liquid or liquid polymer precursor), such as polydimethylsiloxane (PDMS), on a patterned area of the submaster mold 2112 , as depicted in FIG. 21C . Casting the elastomeric material 2115 may include depositing a polymer precursor liquid on the submaster and curing the polymer precursor liquid to create a cured polymer. Accordingly, aspects of the pattern of the submaster 2112 may be transferred to the elastomeric material 2115 to form a patterned polymer mask upon curing. The elastomeric material 2115 may be cast in such a manner that a strip 2120 of the patterned submaster 2112 does not have elastomeric material 2115 cast thereon. In some implementations, this may be accomplished by removing or cutting off a strip of the cast material 2115 after it is cured. In yet further implementations, this may be accomplished by simply not casting the elastomeric material or not depositing the polymer precursor liquid on a portion of the patterned submaster. In yet further implementations, this may be accomplished by some combination of the above. The uncast strip portion 2120 of the patterned submaster 2112 may be at an end of the submaster to enable it to overlap an opposing end of the laminate upon being rolled inside of a casting component.
[0199] Next, a strip 2125 may be removed from the submaster of the laminate created by the previous steps, as depicted in FIG. 21D , in such a manner that the missing strip portion 2120 of the cured polymer 2115 and the missing strip portion 2125 of the patterned submaster 2112 are in staggered locations with respect to one another. The strip 2125 that is removed from the patterned submaster may be at an opposing end of the laminate with respect to the missing strip 2120 of the cured polymer, thereby enabling the laminate to be rolled with these strip portions overlapping one another. In some implementations, a strip 2125 of the patterned submaster 2112 may be removed before a strip 2120 of the cast elastomeric material is removed.
[0200] As in FIG. 21E , the laminate of the submaster 2112 and the cast polymer 2115 may then be rolled and placed in a casting cylinder 2130 , with the unpatterned surface of the substrate 2105 of the submaster 2112 in contact with the inner surface of the casting cylinder 2130 . Accordingly, the outer surface of the laminate may be adjacent to the inner surface of the casting cylinder 2130 when it is rolled. In some implementations, the casting cylinder 2130 into which the laminate is rolled is a sacrificial casting component and utilizes various aspects of the disclosure of SECTION II of this description.
[0201] Rather than rolling the laminate inside of a sacrificial casting cylinder 2130 with the unpatterned surface of the substrate 2105 in contact with the inner surface of the casting cylinder 2130 , in some implementations the laminate is rolled around a sacrificial casting cylinder, with the unpatterned surface of the substrate of the submaster in contact with the outer surface of the sacrificial casting cylinder, according to various aspects of the disclosure of SECTION II of this description.
[0202] A gap 2120 may be formed in the polymer mask 2115 along the length of the cylinder, which may correspond to the strip 2120 of removed/uncast elastomeric material 2115 . A patterned portion of the submaster mold 2112 under the polymer mask 2115 may be exposed from the gap 2120 and extend across the gap 2120 . The staggered locations of the removed/missing strip portions of the laminate enable it to be rolled in such a manner that the gap 2120 is exposed to a patterned portion of the submaster 2112 , but without another seam being formed at the boundary between opposing ends of the rolled laminate due to the overlapped portions.
[0203] As in FIG. 21F , the gap 2120 may then be filled with more liquid elastomeric material (i.e. more polymer precursor liquid) to fill in the gap 2120 in the cured polymer 2115 . As such, the pattern on the submaster mold 2112 may transferred to the added elastometric material upon curing to thereby fill in the seam and form a substantially seamless polymer mask pattern. In some implementations, the filling in the gap may utilize various aspects of the disclosure of SECTION I. For example, in some implementations coaxial cylinders may be assembled using an assembly apparatus that enables liquid polymer precursor to be poured into the gap.
[0204] After curing, the casting cylinder 2130 can be removed from the laminate of the submaster mold 2112 and the polymer mask 2115 having the gap 2120 filled in. The polymer mask 2115 may also be separated from the submaster mold 2112 , yielding a free standing polymer mask having a substantially seamless pattern 2140 on its outer surface, such as depicted in FIG. 21F .
[0205] In some implementations, the cast elastomeric material is PDMS with a thickness in a range from about 1 mm to about 3 mm, to thereby produce a cylindrical mask having a compliant layer 1-3 mm thick.
[0206] In some implementations, the submaster may have a PET film substrate, and the pattern may be formed thereon using a UV-cured polymer.
[0207] Some implementations of the present disclosure can include a free standing polymer mask and a method for fabricating the same.
[0208] In some implementations, the method includes first making a patterned master mold (a patterned master mold may alternatively be referred to herein as a master mask). Next, an elastomeric material, such as polydimethylsiloxane (PDMS), is cast on the patterned area of the master mold to form a patterned polymer mask upon curing (elastomeric material may be alternatively referred to herein as polymer, pre-polymer, polymer precursor, or polymer precursor liquid). The polymer mask is configured to have a missing portion at an end of the master mask mold, wherein a portion of the end of the polymer mask may be cutoff or the elastomeric material may not be cast on a strip at the end of the master mold. The laminate of the mask mold and the polymer mask is then rolled and placed in a casting cylinder in a way that the substrate to the master mold is in contact with the casting cylinder. A gap is formed in the polymer mask along the length of the cylinder, wherein the gap corresponds to the missing portion of the cured polymer mask, and the master mold under the polymer mask is exposed from the gap and extends across the gap. The gap is then filled with additional liquid elastomeric material. As such, the pattern on the master mold is transferred to the added elastometric material upon curing, thereby filling in a seam in the polymer mask pattern. After curing, the laminate of the master mold and the polymer mask can be removed from the casting cylinder and the polymer mask may be in turn separated from the master mold, yielding a free standing polymer mask.
[0209] FIG. 22A is an overhead view of a cylindrical master mold assembly 2230 that can be used to form a polymer mask according to various aspects of the present disclosure. The cylindrical master mold assembly 2230 includes a casting cylinder 2232 , a master mold 2234 and a patterned polymer mask 2236 with a gap 2237 along the length of the cylinder. FIG. 22B is a perspective view of a cylindrical master mold assembly shown in FIG. 22A .
[0210] The patterned mask 2236 may be patterned with a mask pattern in a variety of ways. In one example, the inner surface of the master mold may contain a mask pattern so that this pattern is transferred to the outer surface of the polymer mask. As another example, the polymer mask may be patterned after subsequent fabrication steps and removal of the casting cylinder by patterning the outer surface of the polymer using various lithography methods. As another example, the pattern may also be patterned by some combination above.
[0211] Once the substrate of the master mold 2234 is patterned, an elastomeric material may be cast on the patterned area of the mold 2234 . In some implementations, the elastomeric material may be Polydimethylsiloxane (PDMS), such as Sylgard 184 of Dow Corning™, h-PDMS, soft-PDMS gel, etc. The elastomeric material may be deposited in accordance with any of a number of known methods. By way of example, and not by way of limitation, the elastomeric material may be deposited by dipping, ultrasonic spraying, microjet or inkjet type dispensing, and possibly dipping combined with spinning. After the curing process, the polymer, such as PDMS, is cured to form a patterned polymer mask 2236 on the master mold 2234 . Curing the polymer may depend on the type of polymer being cured and other factors. For example, curing can be done thermally, with UV radiation, or other means.
[0212] The laminate of the master mold 2234 and the polymer mask 2236 is rolled and coaxially inserted into a casting cylinder 2232 in a way that the substrate to the master mold 2234 is in contact with the casting cylinder 2232 (i.e. the outer surface of the laminate is adjacent to the inner surface of the casting cylinder). Since a portion of one end of the polymer mask 2236 is missing, a gap 2237 is formed in the polymer mask along the length of cylinder 2232 , and the underneath master mold is exposed from the gap and extends across the gap. A strip 2239 of the master mold 2234 (i.e. the patterned substrate) can also be removed from the laminate at a staggered location relative to the gap 2237 so that the laminate can be rolled inside of the cylinder 2232 without a seam. The missing strips 2237 , 2239 of the laminate may be at opposite ends of the laminate to allow the laminate to be rolled with the ends of the laminate overlapping each other as depicted in FIGS. 22A-22B .
[0213] The casting cylinder 2232 should be able to be removed after the cylindrical master mold assembly of the present disclosure is formed. According to aspects of the present disclosure, the casting cylinder 2232 may be a thin walled cylinder that is formed from a material that is easily fractured. By way of example, and not by way of limitation, the material may be glass, sugar, or an aromatic hydrocarbon resin, such as Piccotex™ or an aromatic styrene hydrocarbon resin, such as Piccolastic™. Piccotex™ and Piccolastic™ are trademarks of Eastman Chemical Company of Kingsport, Tenn. By way of example, and not by way of limitation, the casting cylinder 2232 may be approximately 1 to 10 mm thick, or in any thickness range encompassed therein, e.g., 2 to 4 mm thick. As shown in FIG. 22A , the polymer mask 2236 is not in contact with the casting cylinder 2232 , and therefore the nanopattern on the polymer mask is protected from damage during the removal. According to additional aspects of the present disclosure, the casting cylinder 2232 may be made from a material that is dissolved by a solvent that does not harm the polymer mask 2236 . By way of example, a suitable dissolvable material may be a sugar based material and the solvent may be water. Dissolving the casting cylinder 2232 instead of fracturing may provide additional protection to the nanopattern.
[0214] According to yet additional aspects of the present disclosure, the casting cylinder 2232 may be a thin walled sealed cylinder made from malleable material such as plastic or aluminum. Instead of fracturing the casting cylinder 2232 , the sealed component may be removed by collapsing the component by evacuating the air from inside the cylinder. According to yet another aspect of the present disclosure, the casting component 2232 may be a pneumatic cylinder made of an elastic material. Examples of elastic materials that may be suitable for a pneumatic cylinder include, but are not limited to plastic, polyethylene, polytetrafluoroethylene (PTFE), which is sold under the name Teflon®, which is a registered trademark of E. I. du Pont de Nemours and Company of Wilmington, Del. During the molding process, the casting cylinder 2232 may be inflated to form a cylinder and once the polymer mask 2236 has cured, the casting cylinder 2232 may be deflated in order to be removed without damaging the polymer mask. In some implementations, such a pneumatic cylinder may be reusable or disposable depending, e.g., on whether it is relatively inexpensive to make and easy to clean.
[0215] Next, the gap 2237 in the polymer mask 2236 along the length of the cylinder is filled with polymer, such as liquid PDMS. During the curing process, the pattern on the master mold 2234 is transferred to the added polymer. As such, a cylindrical master mold assembly 2230 of FIGS. 22A-22B may be formed.
[0216] Curing the liquid polymer may involve applying UV radiation, heat or other means. As an example of applying radiation, the radiation source may be located co-axially within the master mold assembly 2230 . Alternatively, the radiation source may be located outside of the master mold assembly 2230 and the exposure may be made through the casting cylinder 2232 and the master mold 2234 when the casting cylinder 2232 and the master mold 2234 are transparent to the wavelengths of radiation required to cure the liquid polymer.
[0217] The laminate of the master mold 2234 and the patterned polymer mask 2236 may be thereafter removed from the casting cylinder 2232 . Removing the casting cylinder may be performed in a variety of ways. By way of example, and not by way of limitation, the casting component 2232 may be removed by fracturing, dissolving, deflating, or collapsing. By way of example, and not by way of limitation, the casting cylinder can be cut using a saw, a laser, wet or drying etching, or other means. When cutting the casting cylinder, care should be taken not to damage the layer/mask underneath. If a laser is used to cut the casting cylinder, a special layer could be deposited on the inside surface of the casting cylinder to act as an etch stop layer, and this layer should reflective to the light that is used to cut the casting cylinder material. Cutting can be performed using one or more cut lines to make it easier to subsequently peel off the casting cylinder from the laminate. Once the casting cylinder is cut, it can be peeled off of the laminate mechanically. By way of example, and not by way of limitation the casting cylinder may be etched way chemically using etching chemicals that do not also etch away the master mold and the polymer mask within. The casting cylinder may also be removed by other means, and such other means of removal are within the scope of the present disclosure. In some implementations, the casting cylinder 2232 is a sacrificial casting component according to various aspects of SECTION II of this description.
[0218] Next, the polymer mask 2236 may be separated from the master mold 2234 , such as, e.g., by peeling it off, resulting in a free standing PDMS mask having a thickness of 1-3 mm.
[0219] Aspects of the present disclosure include a process 2300 that may use cylindrical master mold assemblies 2230 to form a free standing polymer mask. A flowchart depicting process 2300 that includes various aspects of the above disclosure is depicted in FIG. 23 . Various aspects of process 2300 are also described with reference to mold assemblies 2230 of FIGS. 22A-22B . First, at 2310 , pattern a master mold 2234 . The master mold may be patterned by successively imprinting it with a smaller master mask. At 2320 , form a patterned polymer mask by casting elastomeric materials or polymer on the master mold 2234 and curing the material/polymer. At 2330 , the laminate of the master mold 2234 and the patterned polymer mask 2236 is rolled and inserted coaxially into a casting cylinder 2232 . At 2340 , the gap in the patterned polymer mask 2236 is filled with a liquid polymer. At 2342 , the liquid polymer is cured during the curing process, and thereby transferring the patterns on the master mold along the gap to the cured polymer. At 2350 , the casting cylinder 2232 and the master mold 2234 are removed to form a free standing polymer mask.
VI. Forming a Multilayer Mask Using Casting Components
[0220] Aspects of the disclosure of this SECTION VI include methods and apparatus for forming a multilayered mask using coaxial casting components in multiple stages. Various other methods and apparatus are also included in this section. Forming a multilayered mask in accordance with aspects of this section can be used to form a compliant layer for a rotatable mask, which can provide benefits that may include extra cushioning or compliance in the rotatable mask. There may be various other advantages to implementations of this section.
[0221] It is further noted that this SECTION VI has applicability to and can readily be implemented in various aspects of the remaining SECTIONS I-V of this description, including but not limited to any such sections that may involve forming a patterned compliant layer of rotatable mask. By way of example and not by way of limitation, various aspects of the disclosure of this SECTION VI can readily be applied to implementations of SECTION IV of this description, which involves the patterning of a surface of a casting component.
[0222] Aspects of the present disclosure include a multilayer polymer mask and a method of fabricating the same. The method of making the multilayer polymer mask may involve two stages.
[0223] FIG. 24A depicts an overhead view of a cylindrical master mold assembly in a first stage to form a multilayer polymer mask according to some implementations of the present disclosure. A cylindrical master mold 2410 is formed with features/patterns on the inner surface of the cylinder. A first casting cylinder 2420 is next inserted coaxially into the master mold 2410 to create a cylindrical region between the casting cylinder 2420 and the master mold 2410 . Next, the cylindrical region between the casting cylinder 2420 and the master mold 2410 is filled with a liquid polymer to form a patterned polymer mask 2430 upon curing. Thereafter, the first casting cylinder 2420 is removed and the polymer mask 2430 is peeled off from the interior of the cylindrical master mold 2410 . As such, a free standing polymer mask may be formed. In some implementations, a free standing polymer mask 2430 is alternatively formed using aspects of the SECTION V of this description, wherein a laminate is rolled into a cylinder and a gap in the laminate is filled in to produce a substantially seamless pattern on a cylindrical mask. In some implementations, a free standing polymer mask 2430 is formed using various aspects of SECTION II of this description, including implementations wherein the first casting cylinder 2420 is a sacrificial component and removing the first casting cylinder is performed in accordance with aspects of that section. In some implementations, the cylindrical master mask is formed by patterning the inner surface of the cylinder in accordance with various aspects of SECTION IV of this description.
[0224] FIG. 24B depicts an overhead view of a cylindrical master mold assembly in a second stage to form a multilayer polymer mask according to some implementations of the present disclosure. The polymer mask 2430 is covered with a protective film 2432 and inserted into a second casting cylinder 2440 , with the protective film against the interior surface of the casting cylinder 2440 . A fused silica mask cylinder 2450 is in turn inserted coaxially into the second casting cylinder 2440 and the film-covered polymer mask 2430 , and thereby creating a cylindrical region between the fused silica mask cylinder and the inner diameter of the polymer mask 2430 . This gap is then filled with liquid polymer to form cushion layer 2460 upon curing. Then the second casting cylinder 2440 and the protection film 2432 are removed. As a result, a multilayer polymer mask is formed. In some implementations, the second casting cylinder 2440 is also a sacrificial casting component in accordance with various aspects of SECTION II of this description, thereby allowing yet additional layers to be formed by repeating a process similar to the second stage accordingly.
[0225] FIG. 2 depicts an assembly 200 that may be used to form a patterned polymer mask according to various aspects of the present disclosure. In some implementations, aspects of this disclosure may be used in the first stage mentioned above for forming a multilayer polymer mask. The assembly 200 includes a master mold 204 and a first casting cylinder 202 surrounded by the master mold 204 . The first casting cylinder 202 may correspond to the first casting cylinder 2420 of FIG. 24A . The first casting cylinder 202 may also correspond to a sacrificial casting cylinder, such as sacrificial casting component 830 of FIG. 8A . The master mold 204 and the casting cylinder 202 are coaxially assembled in a way that their axes 206 are aligned, thereby creating a cylindrical region 208 with uniform thickness around the master mold 204 which can define the shape of a polymer layer of the cylindrical mask. The outer diameter of the casting cylinder 202 is larger than the outer diameter of the final fused silica mask cylinder 2450 of the multilayer mask. Polymer precursor can be inserted in the space 208 between the master mold 204 and the casting cylinders 202 . The master mold 204 and the casting cylinder 202 can be held in place using an assembly apparatus (not pictured) that aligns their axes and permits a liquid polymer to be inserted into cylindrical region 208 of the assembly, such as by pouring it through openings or holes in the apparatus. Inserting the polymer precursor may be done, for example, by pouring a liquid or semi-liquid polymer precursor material in through the top of the assembly apparatus into the space between the mold 204 and the cylinder 202 . The polymer precursor may be in the form of a monomer, a polymer, a partially cross-linked polymer, or any mixture of thereof in a liquid or semi-liquid form. The polymer precursor can be cured to form the inner polymer layer of the cylindrical mask. Curing the polymer precursor may involve applying UV radiation or heat. During the curing process, the patterns on the inner surface of the master mold 204 may be transferred to the outer surface of the polymer.
[0226] In the above mentioned first stage, patterning the inner surface of the master mold 2410 may be done using a variety of techniques. For example, the inner surface of the master mold may be patterned by successively imprinting it with a smaller master mask as described above in SECTION III of this description. As another example, a cylinder surface may be patterned using any of a variety of known techniques, including nanoimprint lithography, nanocontact printing, photolithography, etc.
[0227] In the above mentioned first stage, the cast cylinder 2420 may be removed. The patterned polymer mask may be in turn peeled off from the master mold 2410 to form a free standing polymer mask in a thickness of about 1 to 3 mm. It is noted that removing the casting cylinder 2420 and the polymer mask 2430 can be performed in a variety of ways, including various ways as mentioned above in the present disclosure.
[0228] In the above mentioned first stage, the polymer mask 2430 may be covered with a protective layer 2432 . In one example, the protective layer may be a film of polyethylene terephthalate (PET). The protective layer 2432 may be deposited on the polymer mask 2430 , and the film-covered polymer mask 2430 is then inserted coaxially into a second casting cylinder 2440 with the protective film 2432 against the inner surface of the second casting cylinder 2440 . The inner diameter of the second casting cylinder 2440 is equivalent to the inner diameter of the master mold 2410 utilized in the first stage mentioned above. The second casting cylinder 2440 may be a thin walled cylinder that is formed from a material that is easily fractured, such as discussed in associated with the casting cylinder 2232 of FIG. 22A and FIG. 22B or as described with reference to a sacrificial casting component in SECTION II. In some implementations, the protective film enables the second casting cylinder 2440 to be made of separate parts.
[0229] In the above mentioned second stage, a substrate for the rotatable mask, such as a fused silica mask cylinder 2450 is inserted coaxially into the second casting cylinder 2440 and the film-covered polymer mask 2430 . The fused silica mask cylinder 2450 may be a hollow cylinder with an outer diameter that is smaller than the inner diameter of the polymer mask 2430 , thereby creating a cylindrical region of uniform thickness around the mask cylinder 2450 between the outer surface of the mask cylinder and the inner surface of the polymer mask 2430 .
[0230] In the above mentioned second stage, the cylindrical region created between the polymer mask 2430 and the fused silica mask cylinder 2450 may be filled with a liquid polymer and thereby forming a cushion layer 2460 at the inner surface of the polymer mask upon curing. The liquid polymer may be inserted into the cylindrical region in a variety of ways, including various ways mentioned above in the present disclosure.
[0231] In the above mentioned second stage, the second casting cylinder 2440 may be removed. Also, the protective film 2432 may be separated from the polymer mask 2430 having cured cushion layer 2460 . As a result, a multilayer polymer mask including the polymer mask 2430 and the cushion layer 2460 may be formed. Removing the cast cylinder and protective film may be performed in a variety of ways, such as various ways mentioned elsewhere in this disclosure.
[0232] Aspects of the present disclosure include a process 2500 that may use cylindrical master mold assemblies 2400 and 2401 to form a multilayer polymer mask. A flowchart depicting process 2500 is depicted in FIG. 25 that may include various aspects of the above disclosure. Various aspects of process 2500 are also described with reference to FIGS. 24A-24B . At 2510 , the method 2500 may include patterning a master mold/mask 2410 so that the inner surface of the master mold includes a pattern. At 2520 , coaxially assemble the patterned master mold 2410 and the first casting cylinder 2420 so that the axis of both the mold and the cylinder are the same. The casting cylinder 2420 may be a hollow cylinder with an outer diameter that is smaller than an inner diameter of the master mold 2410 , such that a space is left between the mold and the cylinder. At 2530 , space between the mold 2410 and the casting cylinder 2420 is filled with a liquid polymer precursor, resulting in a patterned polymer mask upon curing. At 2540 , the first casting cylinder 2420 is removed and the patterned polymer mask 2430 is peeled off from the master mold 2410 , thereby forming a free standing polymer mask. In some implementations, the casting cylinder 2420 may be a sacrificial casting component in accordance with various aspects of SECTION II of this description, so that the master mask 2410 can be preserved for future use, whereby the casting cylinder 2420 is removed by fracturing, dissolving, collapsing, or otherwise removing it in a manner that enables the cured polymer to be subsequently removed at 2540 from the master mask 2410 after removal of the casting cylinder 2420 . At 2550 , the polymer mask 2430 is covered with a protective layer or film 2432 . At 2560 , the film-covered polymer mask 2430 is coaxially inserted into a second casting cylinder 2440 . At 2570 , a fused silica mask cylinder 2450 is coaxially inserted into the second casting cylinder 2440 and the film-covered mask 2430 . The fused silica mask cylinder 2450 may be a hollow cylinder with an outer diameter that is smaller than an inner diameter of the polymer mask 2430 , thereby leaving a space left between the cylinder and the mask. At 2580 , the space between the fused silica mask cylinder 2450 and the polymer mask 2430 is filled with additional liquid polymer precursor, thereby forming a cushion layer 2460 upon curing. At 2590 , the casting cylinder 2440 and the protective film may be removed to form a multilayer polymer mask. In some implementations, the casting cylinder 2440 may also be a sacrificial casting component.
[0233] Forming a multilayer mask in accordance with various aspects of the present disclosure may provide several advantages. For example, a casting cylinder, e.g. first casting cylinder 2420 mentioned above used to form an outer layer, may be made with separable components having seams, thereby potentially simplifying the process and reducing costs. Polymer used to form a layer in contact with an unpatterned surface, e.g. polymer 2460 used to form inner layer adjacent to the inner surface of outer layer 2430 mentioned above, may also fill in seams caused by using such separate components. Likewise, in some implementations of the present disclosure, a protective film provided over a patterned surface enables a casting tube, e.g. second casting cylinder 2440 mentioned above, to be made of separable components, whereby the protective film may prevent a seam of separable components from transferring to patterned features covered by the film. Furthermore, in some implementations, a mold or mask used in the casting process, such as, e.g., the cylindrical master mold 2410 , does not have to be broken to remove the molded material, thereby preserving it for future use and preventing damage to the molded material by the breaking process.
[0234] Those of ordinary skill in the art will readily appreciate that various aspects of the present disclosure may be combined with various other aspects without departing from the scope of the present disclosure. By way of example and not by way of limitation, it will readily be appreciated by those of ordinary skill in the art that various aspects of the disclosures of SECTIONS I-VI above can be combined into numerous different permutations in fabrication methods and rotatable masks involved in implementing the present disclosure.
[0235] It is noted that various aspects of the present disclosure have been described with reference to multilayered masks generally having two compliant layers. It is noted that aspects of the present disclosure can readily be implemented to form multilayered masks having more than two compliant layers.
[0236] It is further noted that various aspects of the present disclosure have been described with reference to rotatable masks having cylindrical shapes. It is noted that aspects of the present disclosure can readily be implemented in rotatable masks having other shapes, such as, e.g., shapes containing frusto-conical elements or other axially symmetric shapes.
[0237] It is further noted that various aspects of the present disclosure may inverted, switched around, reordered, etc., in order to produce seamless or quasi seamless feature patterns different desired surfaces, such as, e.g., inner or outer surfaces of casting cylinders, final masking cylinders, layers, or other elements used in fabrication processes.
[0238] More generally it is important to note that while the above is a complete description of the preferred embodiments of the present invention, it is possible to use various alternatives, modifications and equivalents. Therefore, the scope of the present invention should be determined not with reference to the above description but should, instead, be determined with reference to the appended claims, along with their full scope of equivalents. Any feature described herein, whether preferred or not, may be combined with any other feature described herein, whether preferred or not.
[0239] In the claims that follow, the indefinite article “a”, or “an” when used in claims containing an open-ended transitional phrase, such as “comprising,” refers to a quantity of one or more of the item following the article, except where expressly stated otherwise. Furthermore, the later use of the word “said” or “the” to refer back to the same claim term does not change this meaning, but simply re-invokes that non-singular meaning. The appended claims are not to be interpreted as including means-plus-function limitations or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase “means for” or “step for.”
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A cylindrical mask may be fabricated using a hollow casting cylinder and a mask cylinder. The casting cylinder has an inner diameter that is larger than the outer diameter of the mask cylinder. The casting and mask cylinders are coaxially assembled and a liquid polymer inserted in a space surrounding the mask cylinder between the inner surface of the casting cylinder and the outer surface of the mask cylinder. After curing the liquid polymer, the casting cylinder is removed. A surface of the cured polymer can be patterned. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a U.S. National Stage patent application of International Patent Application No. PCT/US2013/040539, filed on May 10, 2013, the benefit of which is claimed and the disclosure of which is incorporated herein by reference in its entirety.
BACKGROUND
1. Technical Field
The present disclosure relates generally to completing and producing oil and gas wells, and specifically to a novel method and system for deploying a downhole screen.
2. Background Art
In the process of completing on oil or gas well, a tubular is run into the hole through which produced fluids will be communicated to the surface. Typically, this tubular includes a screen assembly that filters gravel, sand, and other particulate matter from entering the tubular.
When running this completion string into the well, the well may contain drilling mud, brine, or other fluid. Further, this fluid may be laden with rock, cutting chips, sand, and the like. Fluid tends to enter the empty tubular through the screen assembly, and such particulate can substantially plug the screen assembly by the time it has been lowered into the desired position.
Accordingly, it is desirable to provide a screen assembly that resists plugging during run-in-hole operations.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in detail hereinafter on the basis of the embodiments represented in the accompanying figures, in which:
FIG. 1 is a longitudinal cross section of a downhole screen assembly according to a present embodiment, showing a tubular member with apertures formed through the wall, a sleeve slideably disposed about the tubular member with openings that correspond to the apertures, and an actuator that remotely moves the sleeve with respect to the tubular member;
FIG. 2 is an enlarged longitudinal cross section of the downhole screen of FIG. 1 , showing detail of the actuator as actuation of the screen is first begun;
FIG. 3 is an enlarged longitudinal cross section of the actuator of FIG. 2 , showing the body lock ring having been displaced and further engaged the sleeve under the influence of a pressurized interior; and
FIG. 4 is a perspective view of the body lock ring of the actuator of FIG. 3 , showing an interior wall surface having ratchet teeth for unidirectional movement against ratcheting teeth of the slideable sleeve of FIG. 3 ;
FIG. 5 is an enlarged longitudinal cross section of the actuator of FIG. 3 , showing the sleeve moved to the open position after remote actuation.
DETAILED DESCRIPTION
FIG. 1 is a longitudinal cross section of a downhole screen assembly 10 for use within a well 8 according to a present embodiment. Screen assembly 10 includes a tubular member 12 , which may be cylindrical in shape. However, other tubing shapes, such as square tubing, may be used as appropriate. Tubular member 12 includes a plurality of apertures 14 for the intake of well fluids from an exterior or annular region 16 to the interior 18 during well production. Tubular member 12 may have a closed lower end 20 for terminating the bottom of the tubing string in the well. If multiple screen assemblies 10 are provided in a tubing string, only the lowest screen assembly would have a closed lower end.
According to an embodiment, screen assembly 10 includes a sleeve 30 having the same shape type as tubular member 12 , which preferably abuts but can be moved relative to tubular member 12 . Sleeve 30 is shown disposed about the exterior wall surface of tubular member 12 , but in an alternative arrangement (not illustrated), the tubular member could be disposed about the sleeve. Sleeve 30 includes a plurality of openings 32 , which correspond to apertures 14 . Sleeve 30 may have a closed lower end (not illustrated) if it is the last device in tubing string.
FIG. 1 shows sleeve 30 in a shut position where openings 32 are offset from apertures 14 to prevent fluid flow therebetween. In the embodiment illustrated, sleeve 30 can slide longitudinally along axis 24 with respect to tubular member 12 , and openings 32 are radially aligned with longitudinally offset from apertures 14 . However, in other embodiments (not illustrated), openings 32 may be radially offset instead of or in addition to longitudinally offset, and sleeve 30 is capable of rotating with respect to tubular member 12 .
Screen assembly includes a mesh, screen or filter 40 disposed so as to prevent sand, sediment, gravel, and other particulate matter of predetermined size from entering into the interior 18 of tubular member 12 . FIG. 1 shows mesh 40 to be disposed about the exterior of sleeve 30 , but meshing 40 can be disposed within tubular member 12 , within apertures 14 , between tubular member and screen 30 , within openings 32 , or any combination of the above as would be known to one of ordinary skill in the art.
A actuator 50 is operatively connected between tubular member 12 and sleeve 30 which provides for remote, interventionless actuation from the surface of screen assembly 10 to move screen 30 with respect to tubular member 12 so that openings 32 align with aperture 14 to allow fluid flow into the interior 18 . In this manner, downhole screen assembly 10 can be run into a well 8 with sleeve 30 in a shut position, thereby preventing fluid flow into the screen assembly and minimizing the tendency for particulate matter to plug mesh 40 . Once screen assembly 10 has been lowered to the desired position within well 8 , sleeve 30 may be actuated to an open position to allow well production simply by pressurizing interior 18 , as is described below with respect to FIGS. 2-5 .
Although actuator 50 is shown in FIG. 1 as being located at the top of sleeve 30 , it may also be located the bottom or somewhere in the middle of sleeve 30 .
FIG. 2 is an enlarged longitudinal cross section of the downhole screen of FIG. 1 , showing detail of actuator 50 . In a particular embodiment, actuator 50 includes a housing 52 with an inner cylindrical chamber 51 , through which tubular member 12 passes and in which a portion 31 of sleeve 30 is located. Sleeve portion 31 includes ratchet teeth 53 . A body lock ring 54 is provided within housing 52 , and it also includes ratchet teeth 56 that engage ratchet teeth 53 so as to allow axial movement of the body lock ring 54 with respect to sleeve portion 31 in one direction only as described in further detail below.
Body lock ring 54 is axially movable about tubular member 12 within chamber 51 . A first end 55 of body lock ring 54 acts as an annular piston face and is in fluid communication with the interior 18 of tubular member 12 via a conduit 60 . Body lock ring 54 includes inner and outer dynamic seals 57 , 58 , for example grooves with seated o-rings, that seal against an outer wall section of tubular member 14 and in the inner wall of chamber 51 within housing 52 , respectively, yet allow relative movement of body lock ring 54 . The second end 59 of body lock ring 54 rests against a resilient member 62 , such as a coiled spring, which resists an increase of pressure acting on piston face 55 .
Conduit 60 also includes a check valve 64 that selectively connects the interior 18 to the exterior 16 . As illustrated, check valve 64 may include a ball 65 and a seat 66 , whereby the ball 65 is forced and seals against the seat 66 when the fluid pressure within the interior 18 is pressurized with respect to the pressure of the exterior 16 . When the pressure gradient is reversed, ball 65 lifts off of seat 66 and allows flow. Accordingly, when screen assembly is being run into the well, as shown in FIG. 1 , well fluid can enter tubular member 12 through check valve 64 and conduit 60 , rather than through apertures 12 to reduce the risk of plugging the screen assembly. Although only one check valve 64 is illustrated, multiple check valves may be used as appropriate.
FIG. 2 depicts screen actuator 50 after the screen assembly has been run into the well and at the initial point in the actuation sequence where the interior fluid pressure has been raised to shut check valve 64 , thereby allowing the tubular member 14 to be pressurized at the surface, with a concomitant increase in pressure acting at piston face 55 of body lock ring 54 .
Referring now to FIG. 3 , further increasing fluid pressure within interior 18 causes a greater force to be exerted on piston face 55 of body lock ring 54 , thereby compressing resilient member 62 and moving body lock ring 54 toward sleeve 30 . As body lock ring 54 moves toward sleeve 30 , ratchet teeth 56 are forced past and engage ratchet teeth 53 , as explained in greater detail below with reference to FIG. 4 .
FIG. 4 is a perspective view of body lock ring 54 according to a particular embodiment. The first end 55 has a smaller internal diameter than the second end 59 . Near the first end 55 , a circumferential groove 68 is provided around the exterior wall surface into which dynamic seal 58 is seated for sealing against the wall of chamber 51 in housing 52 ( FIG. 3 ). Similarly, a circumferential groove 67 is provided around the inner wall surface into which dynamic seal 57 is seated for sealing against the outer wall section of tubular member 12 ( FIG. 3 ). Body lock ring 54 includes a section having ratchet tooth profile 56 . In particular, and as best seen in FIG. 3 , a typical ratchet tooth profile is similar to a buttress thread; one side of each tooth is perpendicular to the longitudinal axis 24 (as in a square tooth), while the obverse side of each tooth is sloped (as in a ‘V’ tooth).
Preferably, body lock ring 54 includes a number of slots formed therein to provide a limited resilience to allow body lock ring to elastically deform in a radial direction. As the ‘V’ sides of ratchet teeth 56 slide against the ‘V’ sides of ratchet teeth 53 ( FIG. 3 ), an outward radial force is created that temporarily deforms body lock ring 54 , thereby allowing the teeth to pass each other. However, when the square sides of ratchet teeth 56 engage the square sides of ratchet teeth 53 , no radial force is exerted on body lock ring 54 , and no axial motion is permitted. In this manner, body lock ring 54 is capable only of unidirectional motion with respect to portion 31 of sleeve 30 ( FIG. 3 ).
As illustrated, four slots are provided. Two partial slots 70 A, 70 B are formed halfway through body lock ring 54 at first end 55 , one partial slot 71 is formed halfway through body lock ring 54 at second end 59 , and one slot 72 is a full slot formed through the entire ring. However, other numbers and combinations of slots and half slots, or other materials, mechanisms, or techniques may be used as appropriate to obtain a ratcheting effect or unidirectional motion. Additionally, body lock ring 54 is described and illustrated as having a ratchet tooth profile 56 on its inner diameter to engage a ratchet tooth profile 53 on the outer diameter of sleeve portion 31 , a body lock ring with ratchet teeth on its outer diameter may be used as appropriate.
Returning back to FIG. 3 , body lock ring 54 is nearly fully engaged with sleeve 30 due to the pressurization of the interior 18 of tubular member 12 . Now referring to FIG. 5 , the interior 18 is depressurized. Resilient member 62 forces body lock ring 54 back into its original position, and because of the unidirectional ratchet threads 56 , 53 , sleeve 30 is axially moved along with body lock ring 54 into an open position. Openings 32 are now aligned with apertures 14 to allow well production.
Although screen assembly 10 is described herein predominately with respect to a single unit, multiple screen assemblies may be used within a single tubing string. Pressurizing the tubing string works to actuate every body lock ring in the string, and subsequently releasing the internal pressure opens every screen in the completion at once.
The Abstract of the disclosure is solely for providing the United States Patent and Trademark Office and the public at large with a way by which to determine quickly from a cursory reading the nature and gist of technical disclosure, and it represents solely a preferred embodiment and is not indicative of the nature of the invention as a whole. The design of screen assembly 10 as described herein also allows the screen gauge to be remotely adjusted by cycling or adjusting the internal pressure so as to clear the screen or increase production, for example.
While various embodiments have been illustrated in detail, the disclosure is not limited to the embodiments shown. It is apparent that modifications and adaptations of the above embodiments may occur to those skilled in the art. Such modifications and adaptations are in the spirit and scope of the disclosure.
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An interventionless downhole screen that is resistant to plugging during run-in-hole operations and a method for remotely actuating the screen. The screen includes a perforated sleeve that is slideably disposed coaxially with a perforated tubular member. When running, the sleeve is in a closed positioned with its openings offset from the apertures in the tubular member, thereby blocking flow through the screened openings, while a check valve through the tubular member allows fluid ingress. To actuate for production, the tubular member is pressurized, which moves a piston into ratcheting engagement with the sleeve. A subsequent depressurization allows the piston to return to its original position, carrying with it the sleeve to an open position where the sleeve and tubing perforations are aligned for allowing fluid flow into the tubular member.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of U.S. application Ser. No. 860,367 filed May 6, 1986, now abandoned which in turn is a continuation-in-part of U.S. application Ser. No. 800,014 filed Nov. 20, 1985, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to novel photohardenable compositions and to photosensitive materials employing them. More particularly, it relates to free radical addition polymerizable compositions containing an ionic dye-counter ion complex such as a cationic dye-borate anion complex or an anionic dye-iodonium ion complex as a photoinitiator.
U.S. Pat. Nos. 4,399,209 and 4,440,846 to The Mead Corporation describe imaging materials and imaging processes in which images are formed through exposure controlled release of an image-forming agent from a microcapsule containing a photohardenable composition. The imaging material is exposed image-wise to actinic radiation and subjected to a uniform rupturing force. Typically the image-forming agent is a color precursor which is released image-wise from the microcapsules whereupon it reacts with a developer to form a visible image.
One of the problems which has been encountered in designing commercially acceptable panchromatic, full color imaging materials employing these techniques has been the relatively short wavelengths band to which most photohardenable compositions are sensitive to actinic radiation. In most cases, the compositions are only sensitive to ultraviolet radiation or blue light, e.g., 350 to 480 nm.
Full color photosensitive materials are described in U.S. application Ser. No. 339,917, filed Jan. 18, 1982, and U.S. application Ser. No. 620,994 filed June 15, 1984. These imaging materials include a photosensitive layer which contains three sets of microcapsules. Each set of microcapsules is sensitive to a different band of radiation in the ultraviolet or blue spectrum and contains a cyan, magenta or yellow image-forming agent. The absorption spectra of the initiators employed in these microcapsules are never perfectly distinct. There is always some degree of overlap in the absorption curves and sometimes it is substantial. Exposure conditions therefore must be controlled carefully to avoid cross-exposure.
It would be desirable to extend the sensitivity of the photohardenable compositions used in these imaging materials to longer wavelengths. By extending the sensitivity of the photohardenable compositions to longer wavelengths, the amount of overlap in the absorption spectra of the initiators and the concommitant incidence of cross-exposure can be reduced. It would be particularly desirable if compositions could be designed with sensitivities to selected wavelength bands throughout the visible spectrum (400 to 700 nm) since this would provide a visible light-sensitive material which could be exposed by direct reflection or transmission imaging and without image processing.
SUMMARY OF THE INVENTION
It has been found that ionic dye-counter ion compounds, such as cationic dye-borate anion compounds, are useful photoinitiators of free radical addition reactions. Such compounds consist of a visible light absorber (the ionic dye) ionically bonded to a reactive counter ion. The counter ion is reactive in the sense that upon excitation of the dye the counter ion donates an electron to or accepts an electron from the excited dye. This electron transfer process generates radicals capable of initiating polymerization of a monomer.
The mechanism whereby the compounds absorb energy and generate free radicals is not entirely clear. It is believed that upon exposure to actinic radiation, the dye ion is excited to a singlet state in which it accepts an electron from or donates an electron to the counter ion. For a cationic dye-borate anion compound, this can be illustrated by the following equation:
BR.sub.4.sup.- D.sup.+ →D+BR.sub.4.
The lifetime of the dye singlet state is extremely short by comparison to the lifetime of the triplet state. The quenching rate constants which have been observed suggest that the ionic compounds experience a very efficient electron transfer via the singlet state. In solution in the polymerizable compound, tight ionic pairing of the counter ion and the dye is believed to provide favorable spacial distribution promoting electron transfer to such an extent that the transfer occurs even though the lifetime of the singlet state is very short. Of course, this does not mean that electron transfer is restricted to the singlet state. Ionic dyes which have significant populations of triplet state may undergo electron transfer through the singlet state, triplet state, or both singlet and triplet states.
Upon transfer of the electron, a radical is formed. Many of the ionic compounds used as initiators in the present invention do not appear to exhibit back electron transfer. It is believed that following electron transfer, the dye and counter ion become disassociated such that back electron transfer does not occur.
The ionic compounds used in the present invention are different than the collision generated species encountered in other photosensitive systems such as collision complexes which yield encounter complexes, exciplexes and/or contact ion pairs. See for example, Kavarnos, George J. and Turro, Nicholas J., "Photosensitization by Reversible Electron Transfer", Chem. Rev. 1986, 401-449.
In accordance with the present invention the ionic dye and the counter ion are present in the photopolymerizable composition as a stable, non-transient compound, and not as a dissociated ion pair. Formation of the compound is not dependent upon diffusion and collision. As distinguished from photographic materials and compositions containing collision dependent complexes essentially all of the sensitizing dye present in the photosensitive materials of the present invention prior to exposure is ionically bonded to the the counter ion.
The ionic compounds used as initiators in the present invention can also be characterized in that they are soluble in nonpolar solvents such as TMPTA and the like. They are soluble in an amount of at least about 0.1% and perferably at least about 0.3% by weight. While these amounts are not large, they are substantial considering the normally lower solublity of ionic materials in polar solvents. While the compounds are soluble, the dye and the counter ion do not dissociate in solution. They remain ionically bonded to each other.
In dye-sensitized photopolymerizable compositions, visible light is absorbed by a dye having a comparable absorption band, the dye is raised to its excited electronic state, the lifetime of which may be 10 -9 to 10 -3 second, depending upon the nature (singlet or triplet) of the excited state. During this time, absorbed energy in the form of an electron must be transferred to or from the dye molecule to produce the free radical. In prior initiator systems, this transfer is diffusion controlled. Tne excited dye must interact (collide) with another molecule in the composition which quenches the dye and generates a free radical. In the present invention, the transfer is not diffusion (collision) controlled. Electron transfer occurs at greater than diffusion controlled rates. In terms of Stern-Volmer kinetics, this means the quenching constant (Kq) of the excited dye is greater than 10 10 and, more particularly, greater than 10 12 . At these rates, electron transfer can occur through the singlet state.
Thus, the present invention provides a means for generating free radicals from the excited state of an ionic dye and insodoing provides photohardenable compositions which are sensitive at longer wavelengths.
One of the particular advantages of using ionic dye-counter ion compounds as initiators of free radical addition reactions is the ability to select from a wide variety of dyes which absorb at substantially different wavelengths. The absorption characteristics of the compound are principally determined by the dye. Thus, by selecting a dye which absorbs at 400 nm or greater, the sensitivity of the photosensitive material can be extended well into the visible range. Furthermore, compounds can be selected which are respectively sensitive to red, green and blue light without substantial cross-talk.
The ionic dye-counter ion compounds are particularly useful in providing full color photosensitive materials. In these materials, a layer including three sets of microcapsules having distinct sensitivity characteristics is provided on a support. Each set of microcapsules respectively contains a cyan, magenta, or yellow color-forming agent.
The absorption characteristics of the three sets of microcapsules in a full color photosensitive material must be sufficiently different that the cyan-forming capsules can be differentially hardened at a predetermined wavelength or over a predetermined wavelength range without hardening the magenta or yellow-forming capsules and, likewise, the magenta-forming and yellow-forming capsules can be selectively hardened upon exposure respectively to second and third wavelengths without hardening the cyan-forming capsules or hardening the other of the yellow-forming or magenta-forming capsules. Microcapsules having this characteristic (i.e., cyan-, magenta- and yellow-forming capsules which can be selectively hardened by exposure at distinct wavelengths without cross-exposure) are referred to herein as having "distinctly different sensitivities".
As indicated above, because most photohardenable compositions are sensitive to ultraviolet radiation or blue light and they tend not to be sensitive to wavelengths greater than about 480 nm, it has been difficult to achieve microcapsules having distinct sensitivities at three wavelengths. Often it can only be achieved by carefully adjusting the exposure amounts so as not to cross-expose the capsules.
The present invention facilitates the achievement of distinct sensitivities by shifting the peak absorption of at least one of the initiators to higher wavelengths, such as wavelengths greater than about 400 nm. In this manner, instead of attempting to establish distinct sensitivities at three wavelengths within the narrow wavelength range of, for example, 350 nm to 480 nm, sensitivity can be established over a broader range of, for example, 350 to 550 nm or higher. In accordance with the invention, the sensitivity of the microcapsules can be extended well into the visible spectrum to 600 nm and in some cases to about 700 nm. In the preferred case compounds are provided which are respectively sensitive to red, green and blue light.
A principal object of the present invention is to provide photohardenable compositions which are sensitive to visible light, e.g., wavelengths greater than about 400 nm.
A further object of the present invention is to provide visible light-sensitive photohardenable compositions which are useful in the imaging materials described in U.S. Pat. Nos. 4,399,209 and 4,440,846.
Another object of the present invention is to provide photohardenable compositions which are sensitive at greater than about 400 nm and which are useful as photoresists or in forming polymer images.
These and other objects are accomplished in accordance with the present invention which, in one embodiment, provides:
A photohardenable composition comprising a free radical addition polymerizable or crosslinkable compound and a ionic dye-reactive counter ion compound, said ionic dye-reactive counter ion compound being capable of absorbing actinic radiation and producing free radicals which initiate free radical addition polymerization or crosslinking of said addition polymerizable or crosslinkable compound.
Another embodiment of the present invention resides in a photosensitive material comprising a support having a layer of photosensitive microcapsules on the surface thereof, said microcapsules containing an internal phase including a photohardenable composition comprising a free radical addition polymerizable or crosslinkable compound and a an ionic dye-reactive counter ion compound.
Still another embodiment of the present invention resides in a photosensitive material useful in forming full color images comprising a support having a layer of photosensitive microcapsules on the surface thereof, said photosensitive microcapsules comprising a first set of microcapsules having a cyan image-forming agent associated therewith, a second set of microcapsules having a magenta image-forming agent associated therewith, and a third set of microcapsules having a yellow image-forming agent associated therewith, at least one of said first, second, and third sets of microcapsules containing an internal phase which includes a photohardenable composition including a free radical addition polymerizable or crosslinkable compound and an ionic dye-reactive counter ion compound.
A further embodiment of the present invention resides in a photosensitive material comprising a support having a layer of a photohardenable composition on the surface thereof, said photohardenable composition comprising a free radical addition polymerizable or crosslinkable compound and an ionic dye-reactive counter ion compound which provides a quenching constant (Kq) which is greater than 10 10 and preferably greater than 10 12 .
In accordance with more particular embodiments of the invention, the ionic compound is a cationic dye-borate anion compound and still more particularly a cyanine dyeborate anion compound; or an anionic dye compound such as ionic compounds of xanthene dyes with iodonium or pyryllium ions.
DETAILED DESCRIPTION OF THE INVENTION
U.S. Pat. Nos. 4,399,209 and 4,440,846 and U.S. applications Ser. No. 339,917, filed Jan. 18, 1982, and Ser. No. 620,994, filed June 15, 1984, are incorporated herein by reference to the extent that reference thereto may be necessary to complete this disclosure.
Cationic dye-borate anion compounds are known in the art. Their preparation and use in imaging systems is described in U.S. Pat. Nos. 3,567,453; 4,307,182; 4,343,891; 4,447,521; and 4,450,227. The compounds used in the present invention can be represented by the general formula (I): ##STR1## where D + is a cationic dye; and R 1 , R 2 , R 3 , and R 4 are independently selected from the group consisting of alkyl, aryl, alkaryl, allyl, aralkyl, alkenyl, alkynyl, alicyclic and saturated or unsaturated heterocyclic groups.
Useful dyes form photoreducible but dark stable complexes with borate anions and can be cationic methine, polymethine, triarylmethane, indoline, thiazine, xanthene, oxazine and acridine dyes. More specifically, the dyes may be cationic cyanine, carbocyanine, hemicyanine, rhodamine and azomethine dyes. In addition to being cationic, the dyes should not contain groups which would neutralize or desensitize the complex or render the complex poorly dark stable. Examples of groups which generally should not be present in the dye are acid groups such as free carboxylic or sulphonic acid groups.
Specific examples of useful cationic dyes are Methylene Blue, Safranine O, Malachite Green, cyanine dyes of the general formula (II) and rhodamine dyes of the formula (III): ##STR2## n=0, 1, 2, 3, R=alkyl
Y=CH═CH, N--CH 3 , C(CH 3 ) 2 , O, S, Se ##STR3## R', R=alkyl, aryl, and any combination thereof
While they have not been tested, the cationic cyanine dyes disclosed in U.S. Pat. No. 3,495,987 should be useful in the present invention.
The borate anion is designed such that the borate radical generated upon exposure to light and after electron transfer to the dye (Eq. 1) readily dissociates with the formation of a radical as follows:
BR 4 .sup.· →BR 3 +R.sup.· (Eq. 2)
For example particularly preferred anions are triphenylbutylborate and trianisylbutylborate anions because they readily dissociate to triphenylborane or trianisylborane and a butyl radical. On the other hand tetrabutylborate anion does not work well presumably because the tetrabutylborate radical is not stable and it readily accepts an electron back from the dye in a back electron transfer and does not dissociate efficiently. Likewise, tetraphenylborate anion is very poor because the phenyl radical is not easily formed.
Preferably, at least one but not more than three of R 1 , R 2 , R 3 , and R 4 is an alkyl group. Each of R 1 , R 2 , R 3 , and R 4 can contain up to 20 carbon atoms, and they typically contain 1 to 7 carbon atoms. More preferably R 1 -R 4 are a combination of alkyl group(s) and aryl group(s) or aralkyl group(s) and still more preferably a combination of three aryl groups and one alkyl group.
Representative examples of alkyl groups represented by R 1 -R 4 are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, stearyl, etc. The alkyl groups may be substituted, for example, by one or more halogen, cyano, acyloxy, acyl, alkoxy or hydroxy groups.
Representative examples of aryl groups represented by R 1 -R 4 include phenyl, naphthyl and substituted aryl groups such as anisyl. Alkaryl groups include methylphenyl, dimethylphenyl, etc. Representative examples of aralkyl groups represented by groups include benzyl. Representative alicyclic groups include cyclobutyl, cyclopentyl, and cyclohexyl groups. Examples of an alkynyl group are propynyl and ethynyl, and examples of alkenyl groups include a vinyl group.
As a general rule, useful ionic dye compounds must be identified empirically, however, potentially useful dye and counter ion combinations can be identified by reference to the Weller equation (Rehm, D. and Weller, A., Isr. J Chem. (1970), 8, 259-271), which can be simplified as follows.
ΔG=E.sub.ox -E.sub.red -E.sub.hν Z(Eq. 3)
where ΔG is the change in the Gibbs free energy, E ox is the oxidation potential of the borate anion BR 4 - , E red is the reduction potential of the cationic dye, and E h ν is the energy of light used to excite the dye. Useful compounds will have a negative free energy change. Similarly, the difference between the reduction potential of the dye and the oxidation potential of the borate must be negative for the compounds to be dark stable, i.e., Eox-Ered>O.
As indicated, Eq. 2 is a simplification and it does not absolutely predict whether a compound will be useful in the present invention or not. There are a number of other factors which will influence this determination. One such factor is the effect of the monomer on the compound. Another factor is the radial distance between the ions. It is also known that if the Weller equation produces too negative a value, deviations from the equation are possible. Furthermore, the Weller equation only predicts electron transfer, it does not predict whether a particular compound is an efficient initiator of polymerization. The equation is a useful first approximation.
Specific examples of cationic dye-borate anion compounds useful in the present invention are shown in the following table with their λ max.
TABLE__________________________________________________________________________Compound No. Structure λmax (TMPTA)__________________________________________________________________________ ##STR4## 552 nm Ph.sub.3 B.sup.⊖ n-C.sub.4 H.sub.9 ##STR5## 568 nm Ph.sub.3 B.sup.⊖ n-C.sub.4 H.sub.9 ##STR6## 492 nm Ph.sub.3 B.sup.⊖ n-C.sub.4 H.sub.9 ##STR7## 428 nm Ph.sub.3 B.sup.⊖ n-C.sub.4 H.sub.9 ##STR8## 658 nm Ph.sub.3 B.sup.⊖ n-C.sub.4 H.sub.9 ##STR9## 528 nm Ph.sub.3 B.sup.⊖ n-C.sub.4 H.sub.9 ##STR10## 450 nm ##STR11##__________________________________________________________________________No. R' Ar__________________________________________________________________________7A n-butyl phenyl7B n-hexyl phenyl7C n-butyl anisyl__________________________________________________________________________ ##STR12## 550 nm ##STR13##__________________________________________________________________________ No. R' R Ar__________________________________________________________________________ 8A methyl n-butyl phenyl 8B methyl n-hexyl phenyl 8C n-butyl n-butyl phenyl 8D n-butyl n-hexyl phenyl 8E n-heptyl n-butyl phenyl 8F n-heptyl n-hexyl phenyl 8G ethyl n-butyl phenyl__________________________________________________________________________ ##STR14## 570 nm System ##STR15## 10. ##STR16## 590 nm System ##STR17## 11. ##STR18## 640 nm Ar.sub.3 B.sup.-R'__________________________________________________________________________ No. R R' Ar__________________________________________________________________________ 11A methyl n-butyl phenyl 11B methyl n-hexyl phenyl 11C n-butyl n-butyl phenyl 11D n-butyl n-hexyl phenyl 11E n-pentyl n-butyl phenyl 11F n-pentyl n-hexyl phenyl 11G n-heptyl n-butyl phenyl 11H n-heptyl n-hexyl phenyl 11I methyl n-butyl anisyl__________________________________________________________________________ 12. ##STR19## 740 nm System ##STR20##__________________________________________________________________________
The cationic dye-borate anion compounds can be prepared by reacting a borate salt with a dye in a counterion exchange in a known manner. See Hishiki, Y., Repts. Sci. Research Inst. (1953), 29, pp 72-79. Useful borate salts are sodium salts such as sodium tetraphenylborate, sodium triphenylbutylborate, sodium trianisylbutylborate and ammonium salts such as tetraethylammonium tetraphenylborate.
Anionic dye compounds are also useful in the present invention. Anionic dye-iodonium ion compounds of the formula (IV):
[R.sup.5 --I.sup.⊕ --R.sup.6 ].sub.n D.sup.-n (IV)
where D - is an anionic dye and R 5 and R 6 are independently selected from the group consisting of aromatic nucleii such as phenyl or naphthyl and n is 1 or 2; and anionic dye-pyryllium compounds of the formula (V): ##STR21## where D - and n are as defined above are typical examples of anionic dye complexes.
Representative examples of anionic dyes include xanthene and oxonol dyes. For example Rose Bengal, eosin, erythiosin, and fluorscein dyes are useful. In addition to iodonium and pyryllium ions, other compounds of anionic dyes and sulfonium and phosphonium cations are potentially useful.
As in the case of the cationic dye compounds, useful dye-cation combinations can be identified through the Weller equation as having a negative free energy.
Selected examples of anionic dye compounds are shown in Table 2 λ max. ca. 570 nm in TMPTA). In Table 2 the symbol φ is used for a phenyl group and the structure ##STR22##
TABLE 2__________________________________________________________________________ (φ.sub.2 I.sup.+).sub.2 ##STR23## ##STR24## ##STR25## ##STR26## ##STR27## ##STR28## ##STR29## ##STR30## ##STR31## φ.sub.2 I.sup.+ ##STR32## ##STR33## ##STR34## ##STR35## ##STR36## ##STR37## ##STR38## ##STR39## ##STR40## φ.sub.2 I.sup.+__________________________________________________________________________
The most typical examples of a free radical addition polymerizable or crosslinkable compound useful in the present invention is an ethylenically unsaturated compound and, more specifically, a polyethylenically unsaturated compound. These compounds include both monomers having one or more ethylenically unsaturated groups, such as vinyl or allyl groups, and polymers having terminal or pendant ethylenic unsaturation. Such compounds are well known in the art and include acrylic and methacrylic esters of polyhydric alcohols such as trimethylolpropane, pentaerythritol, and the like; and acrylate or methacrylate terminated epoxy resins, acrylate or methacrylate terminated polyesters, etc. Representative examples include ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate (TMPTA), pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, dipentaerythritol hydroxypentacrylate (DPHPA), hexanediol-1,6-dimethacrylate, and diethyleneglycol dimethacrylate.
The ionic dye compound is usually used in an amount up to about 1% by weight based on the weight of the photopolymerizable or crosslinkable species in the photohardenable composition. More typically, the compound is used in an amount of about 0.2% to 0.5% by weight.
While the compound can be used alone as the initiator, film speeds tend to be quite low and oxygen inhibition is observed. It has been found that it is preferable to use the compound in combination with an autoxidizer. An autoxidizer is a compound which is capable of consuming oxygen in a free radical chain process.
Examples of useful autoxidizers are N,N-dialkylanilines Examples of preferred N,N-dialkylanilines are dialkylanilines substituted in one or more of the ortho-, meta-, or para- position by the following groups: methyl, ethyl, isopropyl, t-butyl, 3,4-tetramethylene, phenyl, trifluoromethyl, acetyl, ethoxycarbonyl, carboxy, carboxylate, trimethylsilymethyl, trimethylsilyl, triethylsilyl, trimethylgermanyl, triethylgermanyl, trimethylstannyl, triethylstannyl, n-butoxy, n-pentyloxy, phenoxy, hydroxy, acetyl-oxy, methylthio, ethylthio, isopropylthio, thio-(mercapto-), acetylthio, fluoro, chloro, bromo and iodo.
Representative examples of N,N-dialkylanilines useful in the present invention are 4-cyano-N, N-dimethylaniline, 4-acetyl-N,N-dimethylaniline, 4-bromo-N, N-dimethylaniline, ethyl 4-(N,N-dimethylamino) benzoate, 3-chloro-N,N-dimethylaniline, 4-chloro-N,N-dimethylaniline, 3-ethoxy-N,N-dimethylaniline, 4-fluoro-N,N-dimethylaniline, 4-methyl-N,N-dimethylaniline, 4-ethoxy-N,N-dimethylaniline, N,N-dimethylthioanicidine, 4-amino- N,N-dimethylaniline, 3-hydroxy-N,N-dimethylaniline, N,N,N',N'-tetramethyl-1,4-dianiline, 4-acetamido-N, N-dimethylaniline, etc.
Preferred N,N-dialkylanilines are substituted with an alkyl group in the ortho-position and include 2,6-diisopropyl-N,N-dimethylaniline, 2,6-diethyl-N,N-dimethylaniline, N,N,2,4,6-pentamethylaniline (PMA) and p-t-butyl-N,N-dimethylaniline.
The autoxidizers are preferably used in the present invention in concentrations of about 4-5% by weight.
The photohardenable compositions of the present invention can be coated upon a support in a conventional manner and used as a photoresist or in photolithography to form a polymer image; or they can be encapsulated as described in U.S. Pat. Nos. 4,399,209 and 4,440,846 and used to control the release of an image-forming agent. The latter processes typically involve image-wise exposing the photosensitive material to actinic radiation and subjecting the layer of microcapsules to a uniform rupturing force such as pressure, abrasion, or ultrasonic energy whereupon the image-forming agent is released from the microcapsules for reaction with a developer.
Several processes can be used to form color images as explained in U.S. application Ser. No. 339,917. If the microcapsules contain photosensitive compositions which are sensitive to red, green and blue light, images can be formed by direct transmission or reflection imaging or by image processing. Image processing may involve forming color separations (color-seps) corresponding to the red, green and blue component images and sequentially exposing the photosensitive material to three distinct bands of radiation hereinafter designated λ-1, λ-2, and λ-3 through each color separation. Otherwise, it may involve electronic processing in which the image or subject to be recorded is viewed through a Dunn or matrix camera and the output from the camera electronically drives three exposure sources corresponding to λ-1, λ-2, and λ-3. Alternatively, the image may be produced synthetically, e.g., a computer-generated image.
While the discussion herein relates to forming 3-color full color images, 4-color images are also possible. For example, microcapsules containing cyan, magneta, yellow, and black image-forming agents can be provided which have distinct sensitivities at four wavelengths, e.g., λ-1, ,λ-2, λ-3, and , λ-4.
In accordance with the invention, at least one set of the microcapsules in a full color system contains an ionic dye compound. The other sets also may contain an ionic dye compound, or they may contain a different type of photoinitiator.
In accordance with the preferred embodiments of the invention, a full color imaging system is provided in which the microcapsules are sensitive to red, green, and blue light respectively. The photosensitive composition in at least one and possibly all three microcapsules are sensitized by an ionic dye compound. For optimum color balance, the microcapsules are sensitive (λmax) at about 450 nm, 550 nm, and 650 mn, respectively. Such a system is useful with visible light sources in direct transmission or reflection imaging. Such a material is useful in making contact prints or projected prints of color photographic slides. They are also useful in electronic imaging using lasers or pencil light sources of appropriate wavelengths.
Because the ionic dye compounds absorb at wavelengths greater than 400 nm, they are colored. Typically, the unexposed dye compound is present with the image-forming agent in the image areas and, thus, the color of the compound must be considered in determining the color of the image. However, the compound is used in very small amounts compared to the image-forming agent and exposure sometimes bleaches the compound.
The photohardenable compositions of the present invention can be encapsulated in various wall formers using techniques known in the area of carbonless paper including coacervation, interfacial polymerization, polymerization of one or more monomers in an oil, as well as various melting, dispersing, and cooling methods. To achieve maximum sensitivities, it is important that an encapsulation technique be used which provides high quality capsules which are responsive to changes in the internal phase viscosity in terms of their ability to rupture. Because the borate tends to be acid sensitive, encapsulation procedures conducted at higher pH (e.g., greater than about 6) are preferred.
Oil soluble materials have been encapsulated in hydrophilic wall-forming materials such as gelatin-type materials (see U.S. Pat. Nos. 2,730,456 and 2,800,457 to Green et al) including gum arabic, polyvinyl alcohol, carboxy-methylcellulose; resorcinol-formaldehyde wall formers (see U.S. Pat. No. 3,755,190 to Hart, et al); isocyanate wall-formers (see U.S. Pat. No. 3,914,511 to Vassiliades); isocyanate-polyol wall-formers (see U.S. Pat. No. 3,796,669 to Kirintani et al); urea-formaldehyde wall-formers, particularly urea-resorcinol-formaldehyde in which oleophilicity is enhanced by the addition of resorcinol (see U.S. Pat. Nos. 4,001,140; 4,087,376 and 4,089,802 to Foris et al); melamine-formaldehyde resin and hydroxypropyl cellulose (see commonly assigned U.S. Pat. No. 4,025,455 to Shackle); and UF capsules formed using pectin as a system modifier as discussed in U.S. Pat. No. 4,608,330 to Marabella.
Urea-resorcinol-formaldehyde and melamineformaldehyde capsules with low oxygen permeability are preferred. In some cases to reduce oxygen permeability it is desirable to form a double walled capsule by conducting encapsulation in two stages.
A capsule size should be selected which minimizes light attenuation. The mean diameter of the capsules used in this invention typically ranges from approximately 1 to 25 microns. As a general rule, image resolution improves as the capsule size decreases. If the capsules become too small, they may become inaccessible in the pores or the fioer of the substrate. These very small capsules may therefore be screened from exposure by the substrate. They may also fail to rupture when exposed to pressure or other rupturing means. In view of these problems, it has been determined that a preferred mean capsule diameter range is from approximately 10 microns. Technically, however, the capsules can range in size up to the point where they become visible to the human eye.
An open phase system may also be used in accordance with the invention instead of an encapsulated one. This can be done by dispersing what would otherwise be the capsule contents throughout the coating on the substrate as discrete droplets. Suitable coatings for this embodiment include polymer binders whose viscosity has been adjusted to match the dispersion required in the coating. Suitable binders are gelatin, polyvinyl alcohol, polyacrylamide, and acrylic lattices. Whenever reference is made to "capsules" and "encapsulation" without reference to a discrete capsule wall in this specification or the appended claims, those terms are intended to include the alternative of an open phase system.
The photosensitive material of the present invention can be used to control the interaction of various image-forming agents.
In one embodiment of the present invention the capsules may contain a benign visible dye in the internal phase in which case images are formed by contacting the exposed imaging material under pressure with a plain paper or a paper treated to enhance its affinity for the visible dye. A benign dye is a colored dye which does not interfere with the imaging photochemistry, for example, by relaxing the excited state of the initiator or detrimentally absorbing or attenuating the exposure radiation.
In a preferred embodiment of the invention, images are formed through the reaction of a pair of chromogenic materials such as a color precursor and a color developer, either of which may be encapsulated with the photohardenable composition and function as the image forming agent. In general, these materials include colorless electron donating type compounds and are well known in the art. Representative examples of such color formers include substantially colorless compounds having in their partial skeleton a lactone, a lactam, a sultone, a spiropyran, an ester or an amido structure such as triarylmethane compounds, bisphenylmethane compounds, xanthene compounds, fluorans, thiazine compounds, spiropyran compounds and the like. Crystal Violet Lactone and Copikem X, IV and XI are often used. The color formers can be used alone or in combination.
The developer materials conventionally employed in carbonless paper technology are also useful in the present invention. Illustrative examples are clay minerals such as acid clay, active clay, attapulgite, etc.; organic acids such as tannic acid, gallic acid, propyl gallate, etc.; acid polymers such as phenol-formaldehyde resins, phenol acetylene condensation resins, condensates between an organic carboxylic acid having at least one hydroxy group and formaldehyde, etc.; metal salts or aromatic carboxylic acids such as zinc salicylate, tin salicylate, zinc 2-hydroxy naphthoate, zinc 3,5 di-tert butyl salicylate, zinc 3,5-di-(α-methylbenzyl)salicylate, oil soluble metal salts or phenol-formaldehyde novolak resins (e.g., see U.S. Pat. Nos. 3,672,935; 3,732,120 and 3,737,410) such as zinc modified oil soluble phenol-formaldehyde resin as disclosed in U.S. Pat. No. 3,732,120, zinc carbonate etc. and mixtures thereof.
As indicated in U.S. Pat. Nos. 4,399,209 and 4,440,846, the developer may be present on the photosensitive sheet (providing a so-called self-contained system) or on a separate developer sheet.
In self-contained systems, the developer may be provided in a single layer underlying the microcapsules as disclosed in U.S. Pat. No. 4,440,846. Alternatively, the color former and the color developer may be individually encapsulated in photosensitive capsules and upon exposure both capsule sets image-wise rupture releasing color former and developer which mix to form the image. Alternatively, the developer can be encapsulated in non-photosensitive capsules such that upon processing all developer capsules rupture and release developer but the color former containing capsules rupture in only the unexposed or under-exposed area which are the only areas where the color former and developer mix. Still another alternative is to encapsulate the developer in photosensitive capsules and the color former in non-photosensitive capsules.
The present invention is not necessarily limited to embodiments where the image-forming agent is present in the internal phase. Rather, this agent may be present in the capsule wall of a discrete capsule or in the binder of an open phase system or in a binder or coating used in combination with discrete capsules or an open phase system designed such that the image-wise ruptured capsules release a solvent for the image-forming agent. Embodiments are also envisioned in which a dye or chromogenic material is fixed in a capsule wall or binder and is released by interaction with the internal phase upon rupturing the capsules.
The most common substrate for this invention is a transparent film since it assist in obtaining uniform development characteristics, however, paper may also be used. The paper may be a commercial impact raw stock, or special grade paper such as cast-coated paper or chromerolled paper. Transparent films such as polyethylene terephthalate can be used. Translucent substrates can also be used in this invention.
Synthesis Examples 1 and 2 respectively illustrate the preparation of borates and dye-borate compounds.
SYNTHESIS EXAMPLE 1
Dissolve triphenylborane in 150 ml dry benzene (1M) under nitrogen atmosphere. Place flask in a cool water bath and, while stirring, add n-BuLi, (1.1 e.g.) via syringe. A white precipitate soon formed after addition was started. Stirring is continued about 45-60 min. Dilute with 100 ml hexane and filter, washing with hexane. This resultant Li salt is slightly air unstable. Dissolve the white powder in about 200 ml distilled water and, with vigorous stirring, add aqueous solution of tetramethyl ammonium chloride (1.2 e.g. of theoretical in 200 ml). A thick white precipitate forms. Stir this aqueous mixture about 30 min. at room temperature, then filter. Wash collected white solid with distilled water.
As an alternative synthesis, to a 1.0M solution of 2.0 equivalents of 1-butene in dry, oxygen-free dichloromethane, under inert atomosphere, was added slowly dropwise with stirring, 1.0 equivalents of a 1.0M solution of dibromethane-methylsulfide complex in dichloromethane. The reaction mixture stirred at reflux for 36 hours and the dichloromethane and excess 1-butene were removed by simple distillation. Vacuum distillation of the residue afforded 0.95 equivalents of a colorless mobile oil (Bp 66-7 0.35 mm Hg, "BNMR;bs (4.83 PPM). Under inert atmosphere, this oil was dissolved in dry, oxygen-free tetrahydrofuran to give a 1.0M solution and 3.0 equivalents of a 2.0M solution of phenylmagnesium chloride in tetrahydrofuran were added dropwise with stirring. After stirring 16 hours, the resultant solution was added slowly with vigorous stirring to 2 equivalents of tetramethylammonium chloride, as a 0.2M solution, in water. The resulting white flocculate solid was filtered and dried to afford a near quantitative amount of the desired product Mp 250-2° C., "BNMR;bs (-3.70 PPM).
SYNTHESIS EXAMPLE 2
Sonicate a suspension of a borate salt (1 g/10 ml) in MeOH, to make a very fine suspension. Protect flask from light by wrapping with aluminum foil then add 1 equivalent of dye. Stir this solution with low heat on a hot plate for about 30 min. Let cool to room temperature then dilute with 5-10 volumes of ice water. Filter the resultant solid and wash with water until washings are colorless. Suction filter to dryness. Completely dry initiator compound by low heat (about 50° C.) in a vacuum drying oven. Initiator is usually formed quantitatively. Analysis by H-NMR indicates 1:1 compound formation typically greater than 90%.
The present invention is illustrated in more detail by the following non-limiting Examples.
EXAMPLE 1
Capsule Preparation
1. Into a 600 ml stainless steel beaker, 104 g water and 24.8 g isobutylene maleic anhydride copolymer (18%) are weighed.
2. The beaker is clamped in place on a hot plate under an overhead mixer. A six-bladed, 45° pitch, turbine impeller is used on the mixer.
3. After thoroughly mixing, 3.1 g pectin (polygalacturonic acid methyl ester) is slowly sifted into the beaker. This mixture is stirred for 20 minutes.
4. The pH is adjusted to 4.0 using a 20% solution of H 2 SO 4 , and 0.1 g Quadrol (2-hydroxypropyl ethylenediamine with propylene oxide from BASF) is added.
5. The mixer is turned up to 3000 rpm and the internal phase is added over a period of 10-15 seconds. Emulsification is continued for 10 minutes.
6. At the start of emulsification, the hot plate is turned up so heating continues during emulsification.
7. After 10 minutes, the mixing speed is reduced to 2000 rpm and 14.1 g urea solution (50% w/w), 3.2 g resorcinol in 5 g water, 21.4 g formaldehyde (37%), and 0.6 g ammonium sulfate in 10 ml water are added at two-minute intervals.
8. The beaker is covered with foil and a heat gun is used to help bring the temperature of the preparation to 65° C. When 65° C. is reached, the hot plate is adjusted to maintain this temperature for a two to three hour cure time during which the capsule walls are formed.
9. After curing, the heat is turned off and the pH is adjusted to 9.0 using a 20% NaOH solution.
10. Dry sodium bisulfite (2.8 g) is added and the capsule preparation is cooled to room temperature.
Three batches of microcapsules were prepared for use in a full color imaging sheet using the three internal phase compositions set forth below. Internal Phase A provides a yellow image-forming agent and is sensitive at 420 nm, Phase B provides a magenta image-forming agent and in sensitive at 480 nm, and Phase C contains a cyan image-forming agent and a cationic dye-borate anion complex which is sensitive at 570 nm. The three batches of microcapsules were mixed, coated on a support, and dried to provide a full color imaged sheet.
______________________________________Internal Phase A (420 nm)TMPTA 35 gDPHPA 15 g3-Thenoyl-7-diethylamino coumarin 15 g2-Mercaptobenzoxazole (MBO) 2.0 gPentamethylaniline (PMA) 1.0 gReakt Yellow (BASF) 5.0 gSF-50 (Union Carbide Isocyanate) 1.67 gN-100(Desmodur Polyisocyanate Resin) 3.33 gInternal Phase B (480 nm)TMPTA 35 gDPHPA 15 g9-(4'-Isopropylcinnamoyl)- 0.15 g1,2,4-tetrahydro-3H, 6H, 10H[1]--benzopyrano[9, 9A,1-yl]quinolazine-10-oneMBO 1.0 gPMA 2.0 gMagenta Color Former 8.0 g(HD-5100 Hilton Davis Chemical Co)SF-50 1.67 gN-100 3.33 gInternal Phase C (570 nm)TMPTA 50 gCationic Dye Compound No. 2 0.15 gPMA 2.0 gCyan Color Former 4.0 g(S-29663 Hilton Davis Chemical Co.)SF-50 1.67 gN-100 3.33 g______________________________________
EXAMPLE 2
Capsule Preparation
1 Into a 600 ml stainless steel beaker, 110 g water and 4.6 g isobutylene maleic anhydride copolymer (dry) are weighed.
2. The beaker is clamped in place on a hot plate under an overhead mixer. A six-bladed, 45° pitch, turbine impeller is used on the mixer.
3. After thoroughly mixing, 4.0 g pectin (polygalacturonic acid methyl ester) is slowly sifted into the beaker. This mixture is stirred for 2 hours at room temperature (800-1200 rpm).
4. The pH is adjusted to 7.0 with 20% sulfuric acid.
5. The mixer is turned up to 3000 rpm and the internal phase is added over a period of 10-15 seconds. Emulsification is continued for 10 minutes. Magenta and yellow precursor phases are emulsified at 25°-30° C. Cyan phase is emulsified at 45°-50° C. (oil), 25°-30° C. (water).
6. At the start of emulsification, the hot plate is turned up so heating continues during emulsification.
7. After 10 minutes, the pH is adjusted to 8.25 with 20% sodium carbonate, the mixing speed is reduced to 2000 rpm, and a solution of melamine-formaldehyde prepolymer is slowly added which is prepared by dispersing 3.9 g melamine in 44 g water, adding 6.5 g formaldehyde solution (37%) and heating at 60° C. until the solution clears plus 30 minutes.
8. The pH is adjusted to 6.0, the beaker is covered with foil and placed in a water bath to bring the temperature of the preparation to 65° C. When 65° C. is reached, the hot plate is adjusted to maintain this temperature for a two hour cure time during which the capsule walls are formed.
9. After curing, mixing speed is reduced to 600 rpm, formaldehyude scanvenger solution (7.7 g urea and 7.0 g water) is added and the solution was cured another 40 minutes.
10. The pH is adjusted to 9.5 using a 20% NaOH solution and stirred overnight at room temperature.
Three batches of microcapsules were prepared as above for use in a full color imaging sheet using the three internal phase compositions set forth below.
______________________________________Yellow Forming Capsules (420 nm)TMPTA 35 gDPHPA 15 g3-Thenoyl-7-diethylamino coumarin 15 g2-Mercaptobenzoxazole (MBO) 2.0 g2,6-Diisopropylaniline 1.0 gReakt Yellow (BASF) 5.0 gN-100(Desmodur Polyisocyanate Resin) 3.33 gMagenta Forming Capsules (550 nm)TMPTA 50 gCompound 8A 0.2 g2,6-Diisopropylaniline 2.0 gHD5100 (Magenta color 12.0 gprecursor from Hilton-DavisChemical Co.)Cyan Forming Capsules (650 nm)TMPTA 50 gCompound 11 H 0.31 g2,6-diisopropylaniline 2.0 gCyan Precursor (CP-177 6 gof Hilton-Davis Chemical Co.)______________________________________
The three batches of microcapsules were blended together and coated on a support to provide an imaging material in accordance with the present invention.
Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
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A photohardenable composition comprising a free radical addition polymerizable or crosslinkable compound and an ionic dye-counter ion compound, said compound being capable of absorbing actinic radiation and producing free radicals which initiate free radical polymerization or crosslinking of said compound; and photosensitive materials incorporating the same.
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BACKGROUND OF THE INVENTION
In recent years, the proliferation of audio tapes, of the eight-track and cassette varieties has posed packaging and display problems for retailers. The size of such items makes them particularly susceptible to shoplifting. It has therefore been known to package such tapes in containers substantially larger than the tape itself so as to discourage concealment on or about the person attempting to shoplift the merchandise. Examples of such efforts are shown in U.S. Pat. Nos. 3,587,837; 3,675,763; 3,776,374; 3,828,922; 3,871,516; and 4,245,741. Such prior art devices have several shortcomings. First, several of such devices are intended to be reuseable, that is, the tape is intended for removal by store personnel. As a consequence, the tape may also be removed by a shoplifter. Those prior art devices constructed of paperboard may also be easily ripped open so as to remove the easily concealed tape. Also, the prior art devices are in general designed for receipt of either a cassette or an eight-track cartridge and are not capable of handling both. One exception to this is U.S. Pat. No. 3,871,516, mentioned above. This patent, however, is designed for carrying only one or the other at a time and is only capable of handling one cassette.
It is, therefore, an object of this invention to provide a device which is capable of carrying one eight-track tape or up to two cassettes and which is designed for permanently being secured so as to require a substantial amount of effort for removal and which is of such a size as to prevent easy concealment on or about the person.
SUMMARY OF THE INVENTION
A plastic tape container is designed for one time use and is designed to carry one eight-track tape or up to two cassettes. A number of ribs are provided so as to allow either alternative to be tightly carried within the same cavity and apertures are provided to permit viewing and yet prevent the contents from being removed from the package. Securing means are provided so as to provide a one-way permanent latch and so that the package may be opened only by cutting after the consumer has returned home.
These and other objects of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings wherein like reference numerals are used to refer to the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing the instant invention.
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.
FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.
FIG. 4 is a sectional view taken in the same plane as that of FIG. 2 showing the device in its open state.
FIG. 5 shows the detail of the hinge area.
FIG. 6 is a perspective view showing the hinge area of the alternate embodiment in an open position.
FIG. 7 is a perspective view showing detail of the hinge area of the alternate embodiment in its closed position.
FIG. 8 shows the detail of the hinge area of the alternate embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention, generally 10, is designed for holding cassettes 12 or eight-track tapes 14 therein. Both cassettes 12 and eight-track tapes 14 are understood to include the packaging of the type typically included by the manufacturer; i.e., in the case of cassettes 12 a plastic case of standard dimension and in the case of eight-track tapes a cardboard sleeve or the like.
Container 10 is comprised of a body 16, a cover 18 and a hinge member 20 desirably molded integrally. Body 16 has a first end 22 and a second end 24. A handle 26 is integrally molded to first end 22 of body 16, handle 26 having a handle aperture 28 therein which may be conveniently gripped for carrying. Handle 26 also provides an area 30 upon which indicia may be placed; i.e., of contents, price, or whatever.
Body 16 is comprised of a bottom wall 32 and first and second side walls 34 and 36, respectively. The area contained within body 16 forms body cavity 38. Body bottom wall 32 has viewing apertures 40 formed therein. Viewing apertures 40 are of such size and location as to permit viewing of a substantial portion of the contents of container 10 while preventing removal of the contents when the container 10 is in a closed position.
Cover 18 is comprised of a cover top wall 42 having cover apertures 44 therein. Cover apertures 44 are sized in a manner similar to body viewing apertures 40. Also part of cover 18 are third cover side wall 46 and fourth cover side wall 48. Top wall 42 and side walls 46 and 48 form therein a cover cavity 49. When cover 18 is closed relative to body 16, body cavity 38 and cover cavity 49 are contiguous so as to form a space sized to accept an eight-track or a cassette tape as described more fully hereinafter.
Shown most distinctly in FIGS. 2 and 4 are a number of ribs which serve to locate the contents of the container 10. Cover ribs 50 are located on third and fourth cover side walls 46 and 48 respectively and are spaced from the respective first and second ends so as to snugly accommodate the width of a cassette. Ribs 50 on either side of cover 18 are spaced apart such that an eight-track cartridge may fit between ribs 50 on third side wall 46 and fourth side wall 48. Similarly, body ribs 52 are spaced from body first end 22 and body second end 24 such as to allow two cassettes to be placed in body cavity 38 spaced apart by ribs 52 and yet snugly accommodating cassettes 12. This arrangement is shown most particularly in FIG. 2. The provision of such ribs is important so as to allow the product; i.e., cassettes or eight-track tapes to fit snugly within the container 10 and thereby eliminate manipulation of the contents of the container by a shoplifter.
End ribs 54 are located on the body and body bottom wall 32 and cover top wall 42 respectively. End ribs 54 are spaced from second end 24 by a distance approximately equal to the length of an eight-track cartridge thereby snugly accommodating the cartridge within. When cover 18 is secured to body 16, the spacing between end ribs 54 on body 16 and cover 18 is such that the distance therebetween is approximately the thickness of a cassette.
A number of anti-theft nibs 56 are located on body bottom wall 32 and cover top wall 42 adjacent body first end 22. These nibs are pointed and serve to deter a possible thief from manipulating his fingers into the container 10 in attempting to pull body 16 and cover 18 apart.
First cassette spacing ribs 62 are located at the juncture of first side wall 34 and bottom wall 32. Similarly, second cassette spacing ribs 64 are located at the juncture of second side wall 36 and bottom wall 32. Third cassette spacing ribs 58 are located at the juncture of third side wall 46 and top wall 42 while fourth cassette spacing ribs 60 are located at the juncture of fourth side wall 48 and top wall 42. As can be seen in FIGS. 2 and 4, at least four of each type of ribs are desirable although more or less may be used. Ribs 58 and 62 are spaced from one another by a distance substantially equal to the width of an eight-track cartridge. So also is the spacing between ribs 60 and 64. The spacing between ribs 58 and 62 is substantially equal to the thickness of a cassette as is the distance between ribs 60 and 64.
Side locks 66 are shown in detail in FIG. 3 as well as in FIGS. 1, 2 and 4. Side locks 66 are comprised of tabs 68 located on third and fourth side walls 46 and 48. Side lock tabs 68 have barbs 70 extending from each side thereof. Side lock slots 72 are located on first and second side walls 34 and 36 respectively between ribs 52. Side lock slot 72 has barb slots 74 in the side thereof for retention of barbs 70 therein as is shown most particularly in FIG. 3. Such an arrangement allows an essentially permanent closure as is desired. Side locks 66 may be omitted but the inclusion thereof forms a more secure package.
Body 16 has a first end wall 76 separated from a slot wall 78 by means of webs 84 and 86. Formed between first end wall and slot wall 78 are one or more slots 80 which face upwardly and have located therein ramps 82 as shown in FIGS. 2 and 4. A cover first end wall 77 is made to overlie body end wall 76 when container 10 is closed and end wall 77 has depending therefrom two tabs 81 similar in shape to tabs 68 of side locks 66. Tabs 81 have extending from either side thereof barbs 83 which upon closure wedgingly press past ramps 82 and engage the bottom side thereof as shown in the drawings to provide an essentially permanent closure. The provision of webs 84 and 86 as shown in the drawing assure a sufficient amount of strength such that the closures are quite difficult to open.
The preferred embodiment of the instant invention is formed of a polypropylene plastic. This plastic is not subject to the brittleness of the materials used in several of the prior art devices which may be easily snapped or shattered upon application of force.
In a first embodiment of the instant invention, hinge members 20 are shown in FIGS. 1 and 8 and are attached to the cover 18 and body 16 by means of hinge lines 88. A weakened line 92 is provided on hinge members 20 so as to allow the customer to cut the package open with a pair of scissors or the like upon returning home. Slots 90 are provided adjacent either end of the hinge members to allow the entrance of scissors therein.
The alternative version of the end hinge is shown in FIGS. 5 through 7 wherein hinge members 94 are joined to cover 18 and body 16 at hinge lines 88. Hinge members 94 are provided with an arc shaped cutout having a rib 96 extending therearound. Second end walls 98 and 100 are attached to body 16 and cover 18 respectively. These end walls have located thereon and extending substantially vertically ribs 102 and 104 between which fit hinge members 94. A hook-shaped cutout 106 is located between ribs 102 and 104 and is sized and located so as to accommodate rib 96 therein as shown most particularly in FIGS. 6 and 7. In this embodiment, a weakened line 108 is provided in top wall 42, end walls 98 and 100 and bottom wall 32 to allow the customer to cut the container open as mentioned heretofore.
While the preferred embodiments of the present invention have been described, it should be understood that various changes, adaptations and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.
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A container is designed for packaging cassettes or eight-track tapes at the point of sale. The container will hold up to two cassettes or one eight-track and is designed so that once the merchandise has been inserted, the container is closed permanently and must be cut or otherwise destroyed in order to remove the merchandise, such removal to take place by the consumer at home after purchase.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a fastener assembly, and in particular to a fastener assembly including a nut with an enlarged head and an internally threaded shank.
[0002] Fastener assemblies including a nut with an enlarged encapsulated head have an internally threaded shank comprising a blind hole. The screw is threaded into the hole to secure the two fastener parts together and to clamp the fastened pieces together. These types of fasteners are sometimes referred to as T-nuts.
[0003] In some uses of fastener assemblies, such as in the construction of wall panels for truck bodies, the head of the nut portion of the fastener is exposed on the exterior of the truck. These head portions, which may have a thickness of 0.200 to 0.350 inches from their undersurface to their outer surface, protrude from the otherwise relatively flat wall of the truck, generally in rows or columns when the exterior side wall is secured to the interior wall structure of the truck body. The protruding heads prevent sheet-like advertising or informational signs, such as in the form of truck wraps, from being applied to the exterior side wall of the truck, or else cause a distracting and displeasing appearance.
[0004] Consequently, it can be seen that the need exists for a fastener assembly that can provide an attachment mechanism for truck body exterior side walls, yet will allow for the use of sheet-like advertisements known as full wrap graphics or informational signs to be applied to the exterior side wall without causing a distracting or displeasing appearance.
SUMMARY OF THE INVENTION
[0005] In an embodiment, the present invention provides a fastener assembly including an externally threaded screw and an internally threaded nut for use in securing at least two materials together, wherein a head of the nut portion of the fastener assembly has a low profile. This means that the thickness of the head of the nut which protrudes from the exterior surface of the truck body is much thinner than conventional T-nut heads, and is on the order of no greater than about 0.080 to 0.150 inches, and preferably about 0.100 inches.
[0006] The underside of the head of the nut, in an embodiment, includes an annular recess extending around the shank of the nut which results in an annular lip being formed on the lower surface at the circumference of the head.
[0007] A seal member, such as an O-ring, may be carried on the shank of the nut. The seal member will be pressed into the annular recess as the fastener is tightened to provide a water tight seal between the lower surface of the head and the exterior surface of the truck body. This seal member will prevent water, such as rain, from entering the truck body at the location of the fasteners.
[0008] To secure the nut in place in the wall of the truck body, and to prevent rotation of the nut as the screw is tightened into the nut, the nut may be provided with anti-rotation protrusions. These protrusions may take the form of ribs or ridges provided on the shank of the nut. The ribs may be arranged parallel to the axis of the screw which is inserted into the nut, or the ribs may be angled relative to the axis.
[0009] The outer surface of the nut portion of the fastener may be provided with a salt spray protector in the form of a liquid sealant that will dry with a very thin thickness so as not to meaningfully increase the thickness of the head portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The features of the present invention which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several Figures in which like reference numerals identify like elements, and in which:
[0011] FIG. 1 is a cross-sectional view of a two component wall structure showing the low-profile fastener assembly in place.
[0012] FIG. 2 is a perspective view of a disassembled low-profile fastener assembly.
[0013] FIG. 3 is a side sectional view of the nut portion of the fastener assembly of FIG. 1 .
[0014] FIG. 4 is a side elevational view of an alternate embodiment of the nut portion of the fastener assembly of FIG. 2 .
[0015] FIG. 5 is an end elevational view of the nut portion of the fastener assembly of FIG. 4 , taken from the left side.
[0016] FIG. 6 is a side sectional view of the nut portion of the fastener assembly of FIG. 5 , taken generally along the line VI-VI.
[0017] FIG. 7 is a perspective view of the nut portion of the fastener assembly of FIG. 4 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] FIG. 1 illustrates a portion of a structure 10 (such as a container, portable shelter or truck body) in which a material forming a first structural component 12 such as a wall panel is secured to a second structural component 14 such as an extrusion by means of a plurality of fastener assemblies 16 . Although only two layers of structural components are shown, any number of two or greater structural components may be secured together with the fastener assembly 16 of the present invention.
[0019] As shown in FIGS. 1 and 2 , each of the fastener assemblies 16 includes a first fastener member 18 and a second fastener member 20 . The first fastener member 18 may be in the form of a T-nut which includes a generally disc-shaped head portion 22 . A generally cylindrical shank portion or post 24 is secured to, and extends from, an underside 26 of the head portion 22 . The shank portion 24 may be provided with an anti-rotation structure 28 in the form of a plurality of longitudinal ridges 30 . The longitudinal ridges 30 are formed on a portion of the length of an outer peripheral surface 32 of the shank portion 24 , and extend generally parallel to a longitudinal axis 34 of the shank portion 24 . The longitudinal ridges 30 may have a constant height along their entire length.
[0020] The shank portion 24 is provided with an internally threaded longitudinal bore 36 comprising a blind hole with an opening 38 at a free end 40 opposite the head portion 22 . The outer peripheral surface 32 of the shank portion 24 near the end 40 has a smooth cylindrical shape with an outer diameter smaller than a width dimension of the anti-rotation structure 28 .
[0021] The underside 26 of the first fastener member 18 has an annular recess 46 surrounding the shank portion 24 which forms an annular lip 48 at a periphery 50 of the head portion 22 . When the fastener assembly 16 is tightened into position, a seal member 52 shown in the form of an O-ring which may be carried on the shank portion 24 will be squeezed between the underside 26 of the head portion 22 and the first structural component 12 , which may be the exterior surface of a truck body. In a preferred embodiment, the O-ring 52 has a diameter greater than a depth of the annular recess 46 . For example, the annular recess 46 may have a depth of about 0.025 inches and the O-ring may have a diameter of about 0.0625 inches. This will cause the O-ring to flatten out, as shown in FIG. 1 when the underside 26 of the head portion 22 presses against the surface of the first structural component 12 . In this manner, water, such as rain, will be prevented from entering the truck body at the location of the fasteners.
[0022] While the underside 26 of the head portion 22 may be made without any recess, if a seal member 52 is used with such a first fastener member 18 , the seal member may be squeezed to the point where it extends beyond the outer periphery of the head portion 22 potentially causing an unsightly appearance. Further, by using an annular recess 46 forming an annular lip 48 , there are two concentric seal points, the lip engagement with the first structural member 12 and the O-ring engagement with the first structural member. This improves the sealing characteristics.
[0023] The second fastener member 20 , which may be a screw, is provided with a generally cylindrical shank portion 60 . The head portion of the screw may be a countersink head, a round head, pan head, etc., depending on the application involved. The shank portion 60 is provided with external threads 62 that may extend along the entire length of the shank portion 60 , and is adapted to threadingly engage with the internal bore 36 of the first fastener member 18 . An outer side of the head portion 56 of the second fastener member 20 may be provided with a recessed portion 64 that is adapted to receive a tool for rotationally driving the second fastener member. The recessed portion 64 as shown is adapted to receive a TORX.RTM. driving tool, but it is contemplated that the head portion 56 can be adapted or shaped to receive any suitable driving tool, such as a screwdriver, allen wrench or socket wrench.
[0024] In FIGS. 4-7 a second embodiment of the first fastener member is shown at 18 A. This embodiment varies from the embodiment shown in FIGS. 1-3 in that the ribs 30 A are angled relative to the axis of the shank portion 24 A and the shank portion is relatively shorter than the shank portion 24 shown in FIGS. 1-3 . In all other respects the construction of the first fastener member 18 A in FIGS. 4-7 is the same as that shown in FIGS. 1-3 , namely, there is an annular recess 46 extending around the shank portion 24 A in the undersurface 26 A of the head portion 22 A forming an annular lip 48 A at the periphery 50 A of the head portion. Other similar elements have the same reference number applied as in FIGS. 1-3 , with the addition of an A suffix.
[0025] In operation, the first fastener member 18 is inserted into a bore 66 in the structural component 12 , as shown in FIG. 1 . The bore 66 has a diameter that is slightly less than the diameter of the anti-rotational structure 28 . The longitudinal ridges 30 frictionally engage the inner surface of the bore 66 . The smooth cylindrical shape of the outer peripheral surface 32 of the shank portion 24 is smaller in diameter than the bore 66 , allowing the first fastener member 18 to be easily inserted into the bore.
[0026] After the first fastener member 18 has been inserted into the first structural component 12 , the second fastener member 20 is then inserted through an aligned bore 68 in the second structural component 14 , and a driving tool is used to rotationally drive the second fastener member 20 , thus causing the threaded shank portion 60 of the second fastener member to threadingly engage the threaded inner bore 36 of the first fastener member 18 . The frictional engagement of the anti-rotation structure 28 with the inner surface of the bore 68 prevents rotational movement of the first fastener members 18 with respect to the bore 68 of the first structural component 12 .
[0027] The triangular configuration of the longitudinal ridges 30 (see FIG. 2 ) also allows the first fastener members 18 to be non-destructively removed from the first structural component 12 upon application of a significant axial force. This advantage is particularly important in applications where disassembly and reassembly are required, such as in containers and portable shelters.
[0028] The low profile (thickness) of the head portion 22 , 22 A results in a nearly smooth surface for the first structural member 12 , thereby allowing the surface of the first structural member to be covered with thin, sheet-like advertisements or informational signs, such as truck wraps, without causing any unsightly bumps at the locations of the fasteners assemblies 16 . The low profile also allows the sheet-like advertisements or informational signs to adhere to the surface of the first structural member without the formation of bubbles or gaps which might detrimentally affect the adherence.
[0029] To provide protection for the first fastener components 18 , they may be coated with a salt spray protector which will seal the surfaces of the first fastener components, and particularly the head portion, from salt spray or other corrosive materials that might lead to rusting or deterioration of the first fastener components.
[0030] The outer surface of the head portion 22 , 22 A may be painted white or other color, depending on the covering to be placed over the first structural member and the fastener assembly 16 so that if the sheet-like advertisement or informational sign is scraped or torn in the location of the fastener assembly, the fastener assembly will not be readily visible.
[0031] In a particular embodiment, such as shown in FIGS. 4 and 6 , the first fastener member 18 A may have the following approximate dimensions: Diameter (A) of head 22 A—0.850 inches. Diameter (B) of smooth portion 32 A of shank 24 A—0.335 inches. Length (C) of smooth portion 32 A of shank 24 A—0.135 inches. Axial length (D) of anti-rotational ribs 30 A—0.145 inches. Outer diameter (E) of annular recess 46 A—0.650 inches. Diameter (F) at tops of anti-rotational ribs 30 A—0.375 inches. Thickness (G) of head portion 22 A—0.100 inches. Thickness (H) of head portion 22 A at periphery—0.035 inches. Depth (I) of annular recess 46 A—0.025 inches. Distance (J) from end of anti-rotational ribs 30 A to the underside 26 A of the head portion 18 A—0.010 inches. Threaded recess 36 A sized to receive a ¼ inch—20 threaded screw.
[0032] 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 I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.
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A fastener assembly including an internally threaded nut and an externally threaded screw for securing at least two materials together. The screw has an externally threaded shank and an enlarged head. The nut has a shank with a hole therein. The hole is internally threaded to threadingly receive the externally threaded shank of the screw. The nut has a diametrically enlarged head on an end of the shank opposite from an end with an opening of the hole. The enlarged head of the nut has a thickness not exceeding 0.10 inches. The underside of the enlarged head of the nut may have an annular recess formed therein surrounding the shank.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent Application Ser. No. 60/561,635, filed Apr. 13, 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] This invention relates to window coverings having a stack of cellular material attached between a headrail and a bottom rail in which the material is formed from physically similar remnant pieces of cellular fabric.
[0004] 2. State of the Art
[0005] One common type of window covering has a panel of cellular material connected between a headrail and a bottom rail. These window coverings are sold in standard stock sizes and are custom made by fabricators. The fabricators buy standard headrails, bottom rails and related hardware as well as stacks or blankets of cellular fabrics. The fabricators measure the windows to be covered. Then they select or cut down a standard headrail and bottom rail for each window and cut a panel of material from the blanket which is the correct width and length for the window. Quite often the fabricator will have segments of these blankets which are too small to use. Some of these segments may be as much as twelve feet wide and only three feet long. Typically, this left-over fabric is discarded.
[0006] In U.S. Pat. No. 6,019,864 Jones discloses a method and apparatus for combining segments of cellular material to form a composite window covering. If necessary, the short segments to be interconnected are trimmed to a uniform width consistent with the width of a window area to be covered. Thereafter, a cell of each short length to be connected is trimmed to provide a neat attachment surface strip. Glue beads are run along each edge of each attachment surface strip of the short length of cellular fabric to be attached, and the glue covered attachment surface is pressed against a clean (non-glued) attachment surface strip of a short receiving length to which attachment is to be made. Pressure is released after initial bonding has occurred. The resulting bond between the two segments is thus comprised of two original glue lines, two strips of fabric and the new glue beads. This bond will be twice or three times the thickness of the bonds between all other cells in the combined stack and is quite noticeable. Consequently, there is a need for a method of combining segments of cellular and pleated materials in a manner so that the resulting structure has a uniform appearance.
SUMMARY OF THE INVENTION
[0007] We provide a method for making a window covering from segments of cellular or tabbed material. When using cellular material containing a plurality of cells we select a first segment of cellular material in which there is a top cell having a top surface, at least one glue line on the top surface and a strip of fabric on the at least one glue line. Then we remove the strip of fabric and at least a portion of the glue from the top surface of the top cell. Next we apply a second glue line to the top surface of the top cell. Then we place a second segment of cellular material over the second glue line on the top surface of the top cell and allow the second glue line to cure thereby bonding the second segment of cellular material to the first segment of cellular material.
[0008] The strip of fabric and portion of glue could be removed by grinding, milling, cutting or sanding. One might heat the glue to soften it and then peel or scrape the fabric strip and glue away. One could freeze the glue and then crack the frozen glue to remove the strip of fabric and at leas some of the glue.
[0009] The methods just described for joining segments of cellular materials can also be used for joining segments of tabbed material in which each tab is comprised of two layers of fabric connected together by at least one glue line. We first remove the top layer of fabric and at least a portion of the glue line from the bottom layer of the top tab of a segment of tabbed material. Next we apply at least one new glue line to that bottom layer of fabric. Then we select a second segment of tabbed material in which the bottom tab is a single layer of material. This single layer could have been created from tab comprised of two layers of fabric glued together by removing the outermost layer of fabric and a portion of the glue or may have been made to have only a single fabric layer. Next we place that tab onto the new glue line on the first segment of tabbed material and allow the glue to cure thereby bonding the second segment of tabbed material to the first segment of tabbed material.
[0010] The segments of cellular material as well as the segments of tabbed material may have been cut from a wider segment of material.
[0011] Other objects and advantages of our method of making a window covering from fabric segments will become apparent from certain present preferred embodiments thereof illustrated in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a fragment of a cellular fabric panel;
[0013] FIG. 2 is an end view of the fragment of cellular material shown in FIG. 1 in which the fabric and glue are being removed by grinding;
[0014] FIG. 3 is an end view of a portion of a cellular material made from a laminated fabric;
[0015] FIG. 4 is an enlarged perspective view of a portion of the laminated fabric used in the cellular material of FIG. 3 ;
[0016] FIG. 5 is an end view similar to FIG. 3 after much of the fabric has been removed;
[0017] FIG. 6 is a perspective view of a fragment of cellular material into which heated paddles are being inserted to melt the original glue;
[0018] FIG. 7 is an end view of a fragment of cellular material after much of the original glue has been removed and a new glue line has been applied;
[0019] FIG. 8 is an enlarged view of the glue and portion of the fabric shown in FIG. 7 ;
[0020] FIG. 9 is a perspective view of two cellular segments prepared and aligned for bonding;
[0021] FIG. 10 is an end view of a fragment of tabbed material; and
[0022] FIG. 11 is an end view of two fragments of tabbed material after much of the original glue and to layer of fabric has been removed from the tabs to be joined and a new glue line has been applied to one such tab.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] A typical single cell material 1 shown in FIG. 1 has a series of cells 2 , 3 in which adjacent cells are glued together. There may be a single glue line or multiple glue lines. One common practice is to provide two parallel glue lines 4 , 5 spaced apart a sufficient distance so that holes for lift cords can be easily drilled through the cellular fabric between the glue lines. A fabricator typically purchases cellular material in standard sizes which may be widths of eight to fourteen feet or more and lengths of twelve to fifty feet. From these blankets of cellular material the fabricator cuts a sufficient amount of material to cover a window. Typically, these pieces will be three to four feet wide and six to eight feet in length. Consequently, it is quite common for a fabricator to have left over segments of cellular material. For example, if a fabricator makes three shades which are four feet wide and eight feet long from a 12′×12′ blanket, he will have a segment of cellular material which is twelve feet wide and four feet long. A window of this size is quite rare. However, if the fabricator could cut the twelve foot segment into three four feet widths and then bond them together, he would have a segment that could be used in a four foot wide window having a length up to twelve feet. Since all segments would be cut from the same material the segments would match when bonded together.
[0024] We provide a method of bonding such segments together in which fabric and a portion of the glue along the top surface of the top cell of the segment from which other pieces have been cut is removed. It is not practical to remove all of the glue because some of the original glue will have migrated between the fibers of the fabric. Nevertheless, a substantial portion of that glue is removed.
[0025] Those skilled in the art will recognize that cellular materials used in window coverings have been made from films, paper, woven materials, non-woven materials and composites of one or more films, papers, woven materials and non-woven materials. For ease of reading, the word fabric will be used to describe and claim the segments used in the present method. However, it should be understood that the word fabric as used herein includes films, paper, woven materials, non-woven materials and composites thereof.
[0026] In one preferred method illustrated in FIG. 2 a grinding wheel 8 is used to grind away any fabric 7 and much of the glue of glue lines 4 and 5 . After this fabric and glue has been removed the segment is ready for being bonded to another similarly prepared cellular segment. Although we illustrate a grinding head in FIG. 2 , any material removal process such as milling, sanding or cutting could be used.
[0027] Some fabrics 10 shown in FIG. 4 are laminates of multiple thin layers of fabric. These layers 10 a , 10 b , 10 c and 10 d in the fabric of FIG. 4 are point bonded at spaced apart locations 9 . When such material 10 is used in a cellular product, shown in FIG. 3 , it may be sufficient to simply remove all but one layer of the multi-layer fabric. This can be done by grinding as illustrated in FIG. 2 or cutting or even tearing the other layers 10 a , 10 b , 10 c from the cellular segment. The resulting structure would appear as in FIG. 5 in which there is single layer 10 d on cell 2 . A cellular segment prepared as shown in FIG. 5 is now ready for bonding to another segment.
[0028] Another way of preparing the segments for bonding together is illustrated in FIG. 6 . We provide two elongated paddles 11 , 12 sized to fit within a cell 2 of cellular material 1 . Each paddle has a heated surface 13 , 14 which presses against the area of the cell having glue lines 4 , 5 . An insulator 15 , 16 is provided on and possibly around the edges of each of the heated surfaces 13 , 14 . The elongated paddles 11 and 12 are placed on either side of the bond area and heated sufficiently to melt the adhesive 4 and 5 . The paddles should not be so hot that they damage the fabric. Then, the paddles are removed and the piece of fabric 17 which overlays the glue lines is peeled away taking with it a portion of the melted glue. If desired, any remaining glue may be scraped away with a hot knife. For some cellular products only a single paddle may be sufficient to melt the glue. Upon completion of this process the cellular structure will have a small portion 4 a , 5 a of the original glue lines on the cell 2 . Those portions are shown in FIG. The method illustrated in FIG. 6 can be used only when the original glue is a low temperature thermoplastic adhesive. Such adhesives typically have a melting temperature at 350° F. or less. After the cellular structure has been prepared by grinding or melting as illustrated in FIGS. 2 and 6 , a new glue line 20 is applied over the remaining glue portions 4 a and 5 a . The cellular structure is then ready to be bonded to another cellular segment.
[0029] Yet another method of removing the old glue is to use a laser to heat and soften the original glue so that it can be peeled or scraped away.
[0030] Another way of removing much of the original adhesive 4 , 5 is to freeze the glue and then crack the glue away from the original cell 2 . Yet another method is to apply a solvent such as methylene chloride which will dissolve the glue allowing much of it to be removed. The selected solvent should not damage the fabric.
[0031] When the new glue line 20 is applied as shown in FIG. 8 that line may be wider than the original glue line. This will assure that when the two segments are bonded together there will be an even bond along the front of the shade. However, the new glue line should extend only a slight distance beyond the original glue line, preferably not more than 1 millimeter, so that the cells around the bond area of the two segments do not appear to be differently shaped than other cells in the combined stack.
[0032] After the segments have been prepared as described and a new glue line has been provided as shown in FIGS. 7 and 8 , the segments 1 and 21 are joined together as illustrated in FIG. 9 . For most adhesives the glue line is placed on only one segment. If a two part adhesive is used one part is applied to one segment 1 and the second part is applied to the second segment 21 . The resulting bond will be only 1 to 2 thousands of an inch thick. Such a bond is not perceptibly thicker than any other bond in the segments being joined. Consequently, a casual observer would not know that the finished product was made from two or more segments of cellular material.
[0033] We prefer that the new glue 20 which is used to bond segments together be a high temperature adhesive which will not melt when holes are drilled through the glue for lift cords. However, any adhesive commonly used to make window coverings can be used.
[0034] A fixture or other equipment will be used to combine the two segments together. Suitable equipment is described in U.S. Pat. No. 6,019,864 to Jones which is incorporated herein by reference. Preferably, the equipment will have a wall or other structure against which the front pleats of the stack abut. The glue applicator is a selected distance from that wall, such as 5 to 10 millimeters, and moves along a path parallel to the wall. This assures that the glue line will be the selected distance from, and parallel to, the front pleats. In one embodiment the glue applicator is positioned on the lower segment. Then the upper segment is placed on top of the lower segment and glue applicator. The glue applicator moves between the two segments parallel to the front pleats applying glue as it moves. The weight of the upper segment may be sufficient to press the two segments together and achieve the desired bond. In this embodiment the segments lie in a vertical plane. If desired, the segments could be on a flat or inclined table when being joined together.
[0035] The method we have described for joining segments of cellular materials can also be used for joining segments of tabbed material in which each tab is comprised of two layers of fabric connected together by at least one glue line. Such segments 30 , 31 are shown in FIGS. 10 and 11 . When the process begins tabbed segment 30 has a top tab 34 having a bottom layer of fabric 35 , at least one glue line 36 on the bottom layer of fabric and a top layer of fabric 37 on the at least one glue line. Using any of the techniques described above for removing the strip of fabric from the top cell in the segment of cellular material, we first remove the top layer of fabric 37 and at least a portion of the glue line 36 from the bottom layer 35 of the top tab 34 . Next we apply at least one glue line 38 to the bottom layer of fabric 35 of the top tab. That new glue line is shown in FIG. 11 . Next we select a second segment of tabbed material 31 in which the bottom tab 41 is a single layer of material. This single layer could have been created from tab comprised of two layers of fabric glued together by removing the outermost layer of fabric and a portion of the glue or may have been made to have only a single fabric layer. Next we place tab 41 onto glue line 38 on the bottom layer 35 of the top tab 34 of segment 30 and allow the glue to cure thereby bonding the second segment of tabbed material 31 to the first segment of tabbed material 30 .
[0036] Although we have illustrated single cell materials, our invention is not so limited. Our process could be used for double cell or other multi-cell materials.
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In a method for making a window covering the user selects a first segment of cellular material in which there is a top cell having a top surface, at least one glue line on the top surface and a strip of fabric on the at least one glue line. The strip of fabric and at least a portion of the glue line are removed from the top surface of the top cell and a second glue line is applied to that top surface. A second segment of cellular material is place over the second glue line on the top surface of the top cell of the first segment. The glue line cures and bonds the second segment of cellular material to the first segment of cellular material. If the cellular material has tabbed cells the processes can be used to join the tabs of the two segments together.
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BACKGROUND
1. Field of the Invention
The present application relates generally to sealing a manhole opening against ground water infiltration, and more particularly to an article to rest beneath the manhole cover in the existing opening.
2. Description of Related Art
In many urban areas, the growth and sprawl of towns and cities has decreased the amount of ground surface area which is available for absorbing moisture from rain and snow. Accordingly, this water must be drained off and disposed of through suitable means. In some instances where rainfall is minimal, it is possible to collect this water and dispose of it through the city sewer system. Sewer systems are constructed to accommodate a maximum level of influent to be expected at any one time. As long as the amount of water is minimal, conventional sewer systems may be able to process this without much risk. In areas where rainfall and snowfall is more extreme, conventional sewer systems are not capable of handling the runoff without a gross overdesigning of the system.
A basic fact is that rainfall disposed of through the sewer system has to be processed. Whether the sewer system is designed to accommodate runoff collection or not, the act of processing the runoff costs money. Where moisture is minimal, this cost is not significant. However, where moisture is more prevalent, this cost is non-trivial. Such costs can quickly rise and become a hindrance to city budgets. Therefore, costs associated with processing the moisture through a sewer system is not only costly at the time of building the system but also in the act of processing every gallon that passes through the system. Disadvantages of processing moisture through the sewer system include: higher costs, increased wear and tear on the system, and decreased efficiency to oversize the entire sewer system to accommodate rainfall and sewage.
Some towns or cities have developed a storm drain system to collect and route the moisture away through selected drain systems, away from sewer systems. These have done well but are not completely perfect. Localized flooding still occurs. Additionally, during rainy weather an average manhole in a sanitary sewer system can contribute from 3,000 to 12,000 gallons per day of rainwater to the sewer system for treatment. Although storm drain systems help, they are not enough to avoid the extra costs associated with processing runoff from moisture.
A device is needed that acts to seal or prevent the runoff from entering the manholes. Such a device would act to substantially reduce costs and wear to existing sewer treatment systems. A typical manhole includes a main chamber or barrel section to which the sewer pipes connect. That section is topped with a conical riser upward to a size needed to fit a metal frame for the manhole cover. The metal frame includes an internal lip to support the manhole cover. Water typically passes around the cover because the cover and frame are not sealed.
Many devices have been developed to try and seal manholes to prevent the undesired passing of storm water and other moisture. They can include dishes, bowls, and internally translating sealing sleeves to name a few. Such devices usually become quite complex and involve the reworking and construction of the manhole itself. Such work and cost, given the sheer number of manholes, is undesirable.
It is desirable to have a device that is configured to seal the opening of the manhole and operate with existing manhole frames to avoid the need to reconstruct the manhole assembly. Although some strides have been made, considerable shortcomings remain.
DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the application are set forth in the appended claims. However, the application itself, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a side view of a manhole cover sealing device according to the preferred embodiment of the present application;
FIG. 2 is a side view of the manhole cover sealing device of FIG. 1 within a manhole;
FIG. 3 is a top view of the manhole cover sealing device of FIG. 1 ;
FIG. 4 is a bottom view of the manhole cover sealing device of FIG. 1 ;
FIG. 5 is a side view of an alternative embodiment of the manhole cover sealing device of FIG. 1 ;
FIG. 6 is a side view of the manhole cover sealing device of FIG. 5 within a manhole;
FIG. 7 is a top view of the manhole cover sealing device of FIG. 5 ; and
FIG. 8 is a bottom view of the manhole cover sealing device of FIG. 5 .
While the system and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the application to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Illustrative embodiments of the preferred embodiment are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction.
The system in accordance with the present application overcomes one or more of the above-discussed problems commonly associated with conventional manhole covers. Specifically, the manhole cover sealing device of the present application is configured to be located between the manhole cover and the internal lip of the manhole frame. The device is configured to have a seal that seals along the lip around the full circumference of the lip. The device includes a valve to permit the escaping of gas from the sewer while preventing the passage of moisture into the sewer. Additionally, the device includes a plurality of compression inducing devices that extend into the throat of the manhole and act to initiate a compressive lock. This compressive lock secures device in place to ensure a compressed seal is maintained. This is important given the frequent miss-fitting nature of manhole covers in the frame wherein the cover rocks side to side or fails to actually provide a uniform seating along the lip. The compressive locking feature therefore maintains the seal in a compressed state independent of the fit and weight of the cover itself. These and other unique features of the device are discussed below and illustrated in the accompanying drawings.
The device and method will be understood, both as to its structure and operation, from the accompanying drawings, taken in conjunction with the accompanying description. Several embodiments of the system are presented herein. It should be understood that various components, parts, and features of the different embodiments may be combined together and/or interchanged with one another, all of which are within the scope of the present application, even though not all variations and particular embodiments are shown in the drawings. It should also be understood that the mixing and matching of features, elements, and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that the features, elements, and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless otherwise described.
The manhole cover sealing device of the present application is illustrated in the associated drawings. The device includes seal and a plurality of compression inducing devices configured to maintain the seal in a compressed state. A one-way valve is also included to allow for the passage of sewage gas and restrict water entrance.
Referring now to the drawings wherein like reference characters identify corresponding or similar elements in form and function throughout the several views. FIGS. 1-4 in the drawings illustrate manhole cover sealing device 101 . As stated previously, device 101 includes a seal 103 , a lid 105 , a valve 107 , and one or more compression inducing members 109 . Device 101 is configured to ideally operate within a manhole opening, however, it is understood that the functions and features of device 101 are not so limited. Device 101 may be used with any opening (i.e. a sleeve), whether of one or multiple internal diameters. Lid 105 may be compressed along the upper surface of an opening as opposed to an internal lip herein described.
As seen in FIG. 2 , device 101 is shown in a manhole opening. A manhole opening is defined as the opening made for the acceptance of a conventional manhole cover 99 . It is typically relatively flush with street level and provides an access point for workers to enter the sewer system of a city. A frame 97 is defined in the street (or other surface location) to accept manhole cover 99 . An internal lip 95 is defined in the frame to prevent the falling of the manhole cover 99 through the opening. A throat area 93 of the frame 97 is the decreased diameter portion just below the lip 95 of the frame 97 .
As seen in FIG. 1 , lid 105 is a relatively rigid member made from one or more materials and is configured to enter into the opening of frame 95 . Ideally, lid 105 is sized to be slightly smaller than the internal diameter of the opening. Lid 105 is constructed to support the weight of an individual standing at its center to prevent accidental injury from falling into the sewer. Seal 103 is configured to engage frame 97 and restrict passage of gases, solids, and liquids from passing through frame 97 . Seal 103 is coupled to a lower surface 111 of lid 104 and engages lip 95 . Seal 103 is operated by compressing lid 105 into lip 95 . As seen in FIG. 2 , seal 103 is in a compressed state. Seal 103 is configured to be any type of flexible material that is resistant to absorption. Examples may include elastomeric materials, rubber, and so forth. Seal 103 is configured to wrap around the full circumference of lid 105 along lower surface 111 .
Valve 107 is coupled to lid 105 and is configured to restrict the passage of moisture through the manhole opening. One example of valve 107 is a one-way valve wherein it is designed to allow for gases within the sewer, below lid 105 , to pass upward and into the ambient air. This avoids dangers associated with potential build-up of methane and other gases in the sewer systems. However, as a one-way valve, valve 107 is configured to prevent the passage of moisture (i.e. water) back through lid 105 and into the sewer. Both seal 103 and valve 107 together operate to prevent the passage of moisture into the sewer. This has the advantage of minimizing the amount of water runoff or rain that enters the sewer system and therefore has to be processed and treated.
Device 101 further includes compression inducing device 109 . Device 109 is configured to locate lid 105 within frame 97 and to maintain seal 103 in a compressed state. Device 109 is composed of one or more members that act to engage and grip frame 97 in the throat area 93 , such that when lid 105 is pressed down into the manhole opening and against lip 95 , device 109 produces a sufficient outward force against throat 93 so as to maintain the relative compressive position of lid 105 within frame 97 . This position is independent of the placement of cover 99 . Device 101 does not rely upon the weight of cover 99 to compress seal 103 .
An example of compression inducing device 109 is that of a tang that is cantilevered from lower surface 111 of lid 105 . Tang 109 a is configured to flex in relative position to that of lower surface 111 . Tang 109 a includes a first surface 113 . When in a relaxed state, tang 109 a is in a first position forming more of an acute angle relative to lower surface 111 . When installed in frame 97 , tang 109 a flexes inward into a second position. The second position results in an increased angle relative to lower surface 111 . Additionally, the pressure or force to flex tang 109 a is used to grip frame 97 and maintain the compressive state of seal 103 . Surface 113 is angled to allow tang 109 a to flex inward as it contacts lip 95 when being installed. To remove device 101 , an upward force is applied to pull it out of frame 97 .
Referring in particular to FIG. 3 , an optional groove 117 is formed into an upper surface 115 of lid 105 . Groove 117 is configured to provide a gap between the lid 105 and cover 99 to permit the escaping of gas through valve 107 . Depending on the design of cover 99 , additional space may be required to ensure exhausting gas has a route out of the volume of air defined by frame 97 .
Referring now also to FIGS. 5-8 in the drawings, an alternative embodiment to device 101 is illustrated. Manhole cover sealing device 201 is similar in form and function to that of device 101 of FIGS. 1-4 . Like reference characters identify corresponding or similar elements in form and function throughout the several views. The operation and function of the various features of device 201 are similar to that of device 101 except as noted herein. Device 201 is configured to use a different method of creating a gap of space between lid 105 and cover 99 . Device 201 uses a rib 119 to separate the bottom surface of cover 99 from upper surface 115 of lid 105 . The pattern of rib 119 may be varied for selected purposes. Additionally, the height can be chosen based upon design characteristics. Rib 119 is formed on upper surface 115 and configured to provide the gap between cover 99 and lid 105 to permit the escaping of gas through valve 107 .
In operation of either device 101 or device 201 , lid 105 is located relative to the frame of the manhole. The lid is rested within the frame adjacent lip 95 . Seal 103 contacts lip 95 around the full circumference of the frame. Pressure is applied to the top of lid 105 to compress seal 103 . Devices 109 are used to secure the lid in the compressed position by gripping the throat of the frame. The cover 99 is laid atop of lid 105 . Cover 99 may be laid atop before or after lid 105 is set and compressed.
Along with the spirit of the application, lid 105 may be applied to a hole or sleeve end wherein device 109 is used to grip the internal surfaces of the hole and the seal is applied to the outer upper surface of the hole. Interference fit is used to secure device 109 to the frame and/or surface of the hole.
The current application has many advantages over the prior art including at least the following: (1) water-tight seal around the fame of the manhole to prevent the passage of water into the sewer system; (2) a valve configured to permit the release of gas; (3) a compression inducing device configured to translate within the frame and maintain the compressed state of the seal; (4) simplistic operation and design; and (5) fits existing conventional manholes negating the need to reconstruct the manhole to use.
The particular embodiments disclosed above are illustrative only, as the application may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the application. Accordingly, the protection sought herein is as set forth in the description. It is apparent that an application with significant advantages has been described and illustrated. Although the present application is shown in a limited number of forms, it is not limited to just these forms, but is amenable to various changes and modifications without departing from the spirit thereof.
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A device for sealing the opening of a manhole. The device includes a seal coupled to a lid; a valve; and a compression inducing device. The lid is set within an existing manhole frame and operates without modification. The seal is coupled to a lower surface of the lid and contacts a lip within the frame. The seal is compressed to the lip and the compression inducing device is used to grip the frame below the lip to maintain the compressive state of the seal. The manhole cover is placed on top of the lid. Gases escape through the valve. Water or moisture is prevented from passing through the seal or valve. One or more grooves or ribs are optionally included to create a gap between the lid and the manhole cover for the routing of released gases.
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Reference to related patent, the disclosure of which is hereby incorporated by reference, by the inventor hereof: U.S. Pat. No. 4,784,318, Nov. 15, 1988.
FIELD OF THE INVENTION
The present invention relates to an apparatus and system to generate, position, cut and fold sheets of materials which carry printed information thereon, generated by a computer assisted design (CAD) apparatus, and more particularly to such a system which optimally utilizes a reproduction substrate, such as a web of paper, even if the sheets carrying the printed material are generated in different sizes and formats.
BACKGROUND
Plotter apparatus, such as the output unit of a computer assisted design (CAD) unit, customarily provides drawings on drawing sheets or pages which frequently must be cut individually to the particular format. After having been cut, these drawing pages then can be folded to standard sizes, for example by hand, or by a folding machine.
THE INVENTION
It is an object to automate the generation of printed drawing sheets, derived from a plotter or other CAD system, in which the plotter generates drawings on a substrate web, typically of paper, which drawings may have, selectively, different size; and to automatically cut these drawings to the appropriate format and then to fold them, eliminating all manual intervention.
Briefly, a plotter includes a program which applies printed material on a substrate web, typically on a paper web, of predetermined width. The program so controls the plotter that the material is applied in printed form on the web so that those formats or sizes of drawings generated by the plotter which are of the same size are located, in groups, on the web to optimally utilize the predetermined width thereof. Longitudinal cuts and cross cuts are then made to sever the individual drawings in the web, in accordance with the respective format, and to form cut drawings; the cut drawings are then fed, individually, to a folder.
In accordance with a feature of the invention, the sheets are fed sequentially to the folder. The sheets, after having been cut, preferably are individually fed and aligned sheets. The sheets, after having been cut, preferably are aligned against an alignment or abutment stop element or groups of elements, or, for example, a stop rail, from which they are then fed to the folder so that the folder will receive the respective sheets in a predetermined position and alignment, regardless of the prior position of the respective cut sheets or drawings on the web.
The plotter program is so arranged that the printed subject matter is placed on the web in the same general direction, that is, places the printed subject matter on the web so that the legend with respect to the drawing will be in a predetermined position.
In accordance with a feature of the invention, a separating table is provided which includes longitudinal and transverse sheet transport means for the cut sheets or drawings; light gates are provided, distributed across the width of the separating table, and associated with possible positions of drawings on the cut sheet, controlling the sequencing circuit and a logic stage to sequentially feed the cut sheets against a stop element, for example a stop rail, for subsequent feeding of the sheets in predetermined position to a sheet folder.
The system has the advantage that drawing sheets, derived from a plotter and which may have different sizes or formats, can be automatically cut from a web, and automatically appropriately folded, without any operator or manual intervention. It, therefore, permits handling of drawings of various sizes and formats while providing, as the output, drawings folded to a predetermined folding pattern.
DRAWINGS
FIG. 1 is a schematic representation of a plurality of drawings of different formats placed on a substrate paper web;
FIG. 2 is a schematic illustration of a top view of a separating table, showing the apparatus and units for cutting, separating and moving drawing sheets, derived from a web;
FIG. 3 is a schematic vertical cross-sectional view through a transport arrangement, utilizing a ball transport; and
FIG. 4 is a schematic block diagram illustrating the control system for effecting the respective operating steps and controlling the apparatus of FIG. 2.
DETAILED DESCRIPTION
Referring first to FIGS. 1 and 2:
A plotter 1 (FIG. 2) or a similar computer assisted design (CAD) system to generate images on a web, for example drawings, pictures, writing or the like, prints out the respective subject matter on a web 2, which is transported past the plotter 1 by a suitable transport mechanism, not shown. A typical printing apparatus may, for example, utilize electrostatic reproduction.
The drawings may have predetermined different formats. These formats are standardized, and one standardization system utilizes the DIN standards as follows:
______________________________________Designation Dimension-mm Approx. Conversion to Inches______________________________________A0 841 × 1180 33 × 43.5A1 594 × 841 23.5 × 33A2 420 × 594 16.4 × 23.5A3 297 × 420 11.8 × 16.4A4 210 × 297 8.3 × 11.8A31 210 × 841 8.3 × 33A32 210 × 594 8.3 × 23.5______________________________________
The sizes A31 and A32 are special sizes, utilized, for example, for long circuit diagrams. The paper web 2 has a width B, which corresponds to the width of the largest format or size of print which can be generated by the respective CAD plotter 1. It may, for example, correspond to the width of the format A0, that is, have a width, apart from transport margins which may be perforated, of about 845 mm, or somewhat over 33 inches. The customary drawing formats usually use drawing sheets of smaller dimension.
The software of the plotter 1 is so programmed that drawing sheets of the same size and which will fit across the width B are collected in a group or block. The drawings are so arranged and oriented that the legend field 16 is always at the same side, for example adjacent the bottom right corner of the drawing. The number of drawings combined in such a block which are shown in FIG. 2, as an example, at F1, F2, F3, depends on the size of the format of the drawing, optimally using the width B of the web, as clearly appears from FIG. 1. Blank transverse separating strips 4' are preferably provided, to clearly separate the drawings, although this is not strictly necessary. These separating strips, without information content, form scrap which can be discarded.
The continuous web 2, with the information generated thereby appropriately positioned thereon (FIG. 1), is then fed into a cutter 3 (FIG. 2) which cuts or slits the web in transverse and longitudinal direction, by making transverse and longitudinal cuts 7, 8, to generate rectangular drawings in appropriate format of predetermined size, for example of standard sizes A0 to A4 and special sizes A31, A32. A suitable cutter is described in the referenced U.S. Pat. No. 4,784,318, by the inventor hereof, the disclosure of which is hereby incorporated by reference. The plotter is programmed to also apply marginal marks on the sheets, for example in a bar code, or other suitable machinereadable code, which controls the knives or slitters in the cutter 3 to appropriately cut the web. Preferably, the knives for the cross cut 7 are first controlled to make the cross cut at the leading edge, and then the slitters to make the longitudinal cut 8 cut the longitudinal slits which, then, can terminate in a further cross cut adjacent one of the blank strips 4'.
The sequencing is entirely selectable by the operator and, once set, need not be changed. The sequencing of cutting, of course, can be reversed.
The thus generated drawing sheets, for example F1, F2, F3, cut to the predetermined format, are then fed on a separating table 4. They are then fed to a folder 5, of well known construction, as will appear.
The individual, already cut sheets 32 (FIG. 2) are fed to the table 4 by a plurality of transport belts 6, to move the sheets in the direction of the arrow E. Photo-electric sensors, such as photo cells 10, 11, 12, 13, are located on or in association with the table 4. When the photo cells 10-13 are covered, or block a light beam directed thereto when the sheets 32 are moved in the direction of the arrow E, the transport belt 6 is stopped. Thereafter, the sheet which is immediately adjacent an alignment rail 25 is moved by a transport system 15 towards the folder 5, in the direction of the arrow E. Thereafter, subsequent sheets are moved in engagement with the alignment rail 25, for further transport to the folder 5. The sequencing and control will be explained below.
Referring to FIG. 3, the transport system 15 is formed by the combination of a ball 17 and a transport wheel 26, cooperating with a sheet 32 to feed it against, or, depending on the direction of the transport system 15, along the rail 25. The ball 17 is retained, loosely, in a cage 22. A support sheet 19, forming for example part of the table 4, is formed with small openings through which the drive wheel 26 passes in a cutout or slit. The ball 17 can be raised off the surface of the sheet 32 by a solenoid coil 18, wound on a central core 21. The core 21 has a part-spherical segmental recess 20, so that a small gap is provided between the ball 17 and the core 21. When the solenoid 18 is energized under control of a control system--to be described below--the solenoid 18 will attract the ball 17 which, typically, is made of steel, to be lifted off the sheet, thereby interrupting transport. When the ball 17 is dropped, the sheet 32 can engage the stop rail 25, so that the sheet 32 is moved upon rotation of the wheel 26 along the stop rail 25 in the direction of the arrow E towards the folding system 5.
Referring now to FIGS. 2 and 4: The four light gates 10-13 are so located below or above the separating table 4 that the light gates 10, 11, 12 are positioned on a straight line, transverse to the transport direction E. The light gate 13 is offset in the direction of transport upon movement of the sheet towards the folder 5.
OPERATION
The cutter 3 cuts the web 2 by longitudinal and transverse cuts 8, 7 in rectangular formats to derive cut sheets 32 which are fed to the separating table 4 by four transport belts 6, driven by a motor 56. The sheets 32, thus, are moved in the direction of the arrow E. The motor 56 is energized and de-energized, respectively, by a relay 57, forming a part of a bank of relays 42 (FIG. 4). Let it be assumed that the cutter 3 cuts the web 2 into three sheets F1, F2, F3, each of the format A3. Sheet F3 covers the light gate 12; the second sheet, F2, covers the light gate 11, and the third sheet, F1, covers the light gate 10. As soon as all three light gates 10, 11, 12 are covered, drive motor 56 stops the transport belts 6, that is, relay 57 is de-energized. When this state is sensed, the sheet 32 designated F1 is transported by the ball transport system 15 and 15'--see FIG. 3--in the direction of the arrow E. The current supply to the relays 58, 59 of relays 15, 15', respectively is interrupted, so that the magnets 18 will be de-energized, permitting the balls 17 of the respective transport systems 15, 15' to drop on the sheet F1. The sheet F1, then, is fed by the driven rollers 26 along the lateral engagement rail 25 in the direction of the arrow E. Upon feeding of the sheet, the light gate 10 will become uncovered. When this is sensed, the relay 60 energizes motor 61 to drive the transport rollers 24 for transverse transport, and engage the sheet F2. The sheet F2 is thereby moved in the direction of the arrow C until it engages against the abutment or engagement rail 25. In this position, the light gate 10 is again covered, which de-energizes the solenoids 18 of the respective transport systems 15, 15', so that the sheet F2 is fed in the direction of the arrow E, just like the sheet F1 previously, and in a similar manner. Upon feeding of the sheet F2, the light gate 10 is again uncovered. As a consequence, and as logically sensed by the logic stage 38 and the sequencing stage 46, the relay 60 of the motor 61 as well as the relay 62 of the motor 63 are energized, so that the transport rollers 14 as well as 24 are again operated. This feeds the sheet F3 in the direction of the arrow C until it engages the abutment rail 25. The light gate 10 is now again covered, causing the sheet F3 to be fed by the ball transport systems 15, 15' along the abutment rail 25 in the direction of the arrow E to the folder 5 as described above. At this stage, all three light gates 10, 11, 12 will be uncovered, and the sequencing circuit 46, then, controls the relay 48 to close so that longitudinal transport with the transport belts 6 and the cutter machine 3 can again commence.
It may occur that comparatively long sheets, that is, sheets of a long format such as those of A31, A32 are to be cut. If such sheets are to be handled, the transport belts 6 would be stopped prematurely when a preceding sheet has cleared the light gates 10, 11, 12. Such extra-length sheets, e.g. of format A31 are transported by the longitudinal transport belts 6 while the light gate 13, offset with respect to the light gates 10-12 in the direction of the arrow E, is covered. The cutter 3 cooperates with an optical coupler 30 (FIG. 4), also connected to an interface, since it is necessary to recognize the respective formats of the cut sheets before the cut sheets reach the separating table 4. The opto coupler 30 is connected in parallel with the longitudinal and cross cut system 8, 7 in such a manner that, when the cross cut 8 of the cutting machine is made, the longitudinal transport by belt 6 towards the separating table is stopped, by disconnecting the motor 56, when the light gate 13 is also covered. The sequencing circuit 46 (FIG. 4) with the relay 48 controls an interlock which has the effect that the cutter 3 can supply cut sheets 32 to the separating table 4 only when all the light gates are uncovered.
It is, of course, equally possible to set the light gate 13 behind the light gates 10, 11, 12--with respect to the transport direction E--and then suitably modifying the control software by interrupting longitudinal transport when the preceding or pre-positioned light gate is no longer covered.
The ball transport systems 15, 15'of the associated relays 58, 59 are so connected and programmed that the ball transport system is connected by the associated magnet controlling the rollers 14, 24, 26 to lift the balls 17 unless transport is desired, since the sheets could not readily slip between the rollers 14, 24, 26, respectively, if the balls 17 were in engagement therewith.
The connecting system of FIG. 4 further shows that the opto coupler 30 is connected to a decoding stage 34, typically an EPROM, which, in turn, is connected to a memory 36 which is coupled to a logic stage 38. The logic stage controls a driver stage 40 which is connected to drive the respective relays 55, 57, 58, 59, 60, 62 of the relay block 42; of course, the relays can be replaced by other suitable switching elements. The outputs of the light gates 10-13 are coupled to a signal shaping and processing stage 44, of suitable circuitry, which, in turn, is connected to the sequencing circuit 46, coupled to the logic stage 38.
The invention has been described with an example in which three sheets 32 are sequentially fed to the folder 5. Of course, a larger or smaller number of sheets can be cut from the web 2, and it is only necessary to suitably program the cutter 3 to cut the sheets as derived from the CAD plotter 2; the system will then, automatically, adapt itself in similar, but modified operation to automatically feed the respective cut sheets against the engagement element 25, typically a rail, for subsequent folding by the folding apparatus 5, which can be tied electrically to the plotter and/or the cutter to effect appropriate folding in accordance with the format of the respective sheet, as cut by the cutter 3. Information or data relating to that format is available in electronic form from CAD 1 and the cutter 3.
Various changes and modifications may be made; the respective elements are all well known structures, available commercially as units, or, respectively, as described in the referenced U.S. Pat. No. 4,784,318, by the inventor hereof.
Suitable electrostatic plotters 1 are manufactured by and available from Versatec Headquarters, Santa Clara, Calif., or Sanders California Computer Products, Inc., Anaheim, Calif., or Hewlett Packard, San Diego, Calif. A program which optimally aligns the respective drawings for such plotters is available from SwS software Service GmbH, Eschweiler, Germany, or from O. Bay aG, Subingen, Switzerland.
A suitable folder 5 is described in Europ. patent publication no. 89810540.8, corresponding to U.S. Ser. No. 07/399 584, now U.S. Pat. No. 5,645,039.
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A plotter (1) provides, in accordance with command inputs, drawings on a web (2) of predetermined width; the drawings may have different sizes or formats, and are provided by the plotter for optimal distribution of the sheets across the width (B) of the web. These drawings are placed on the web in groups, and the web is then cut longitudinally as well as transversely to provide the individual sheets which are fed on a separating table. The separating table is provided with longitudinal and transverse feeding systems (6, 56, 14, 24, 61, 63, 15, 15'), and with electric eyes or opto-electric gates (10-13) which, selectively, control longitudinal and transverse feeding apparatus to move the sheets against a reference or alignment rail (25) from where they are then fed sequentially, individually, to a folding apparatus (5). The systems permits automatic cutting and folding of drawing sheets, for example, from a web in accordance with the formats of the sheets, which are known from the plotter program.
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This invention relates to an improvement in structure for mounting the expander rods of a mechanical tube expander, which expander is used for fixing fins on the tubes of tube and fin-type heat exchangers.
DESCRIPTION OF THE PRIOR ART
FIG. 6 illustrates a conventional structure for mounting the expander rods 1 of a mechanical tube expander of the type indicated above. The mounting structure comprises a pressure plate 2 and a rod-holder plate 3. The rod-holder plate 3 contains a releasable lock in the form of a spring-urged ball 4 which is receivable in a recess 5 in the expander rod 1. The geometry of the ball 4 and recess 5 is such that the ball 4 cannot be moved out of the recess 5 simply by pulling downwardly on the expander rod. The expander rod 1 cannot move upwardly from the position shown in FIG. 6 because of the pressure plate 2. In order to move the ball 4 out of the recess 5, a pin 6 is pushed upwardly through the opening 7 from the underside of the rod-holder plate 3 to engage the ball 4 and move it upwardly into the passage 8 in the rod-holder plate as shown in the righthand portion of FIG. 6. Then the expander rod 1 is removed from the rod-holder plate 3 by pulling it downwardly. Although this mounting structure for expander rods is effective for its intended purpose, it is relatively time-consuming to release a large number of expander rods 1 from an expander because of the need to insert a pin into the opening 7 associated with each of the rods. Also, because a vertical mechanical tube expander commonly has a height of more than about 10 feet and the expander rods are mounted toward the upper end thereof, a worker must stand on a raised platform or ladder, and lean in toward the machine in order to remove the expander rods. This can be difficult and may present safety problems.
U.S. Pat. No. 4 771 536 discloses an expander rod mounting structure in which a key projects into each opening in the rod-holder header. The expander rod is specially shaped so that it can be inserted into the rod-holder header and then rotated about its lengthwise axis to a position in which the key releasably locks the expander rod in place. Specially shaped expander rods are needed in this structure.
SUMMARY OF THE INVENTION
The invention provides an improvement in a mechanical tube expander for expanding tubes into interlocked relationship with fins to form tube and fin-type heat exchangers. The mechanical tube expander comprises a frame, means for holding an assembly of fins loosely stacked on tubes and a pressure plate carrying a plurality of expander rods which are aligned with the tubes. The expander rods have tube-expanding means at one end thereof and detent-receiving means close to the opposite end thereof. The detent-receiving means cooperates with means for releasably locking the expander rods to the pressure plate. Further, means are provided for reciprocating the expander rods with respect to the assembly of tubes and fins in order that the tube-expanding means will expand the tubes into interlocked relationship with the fins that are stacked thereon. The means for releasably locking the expander rods to the pressure plate comprises a rod-holder plate having through openings for holding the expander rods and detent means receivable in the detent-receiving means on the expander rods for releasably securing the expander rods to the rod-holder plate. A movable slide plate is disposed beyond the detent-receiving means of the expander rods. The slide plate has through openings corresponding in number and arrangement to the number and arrangement of the expander rods. Means are provided for moving the slide plate between a first position in which the detent means is received in the detent-receiving means and said through openings in said movable slide plate are out of alignment with the expander rods so that the expander rods are locked to the rod-holder plate, and a second position in which said detent means is displaced outside said detent-receiving means and said through openings in the movable slide plate are in alignment with the expander rods so that the expander rods can move into the openings in the slide plate and be released from locked relationship to the rod-holder plate.
The improved structure of the invention for mounting the expander rods does not require modification of the physical structure of the expander rods and the releasable lock structure that has previously been used with good results in this field. The improved structure according to the invention permits an existing mechanical expander to be retrofitted easily in order to employ the improved mounting structure thereon. The improved structure makes it possible to remove the expander rods more easily than was possible heretofore because each of the expander rods can be moved upwardly and thereby displace the ball from the recess in the expander rod. Then the expander rod can be rotated about its lengthwise axis and thereby move the recess out of vertical alignment with the ball so that the ball cannot re-enter the recess. Then the expander rod can be pulled downwardly to remove it from the rod-holder plate. The expander rods can be removed from below without requiring the workman to climb up the machine. The expander bullets can be screwed into and tightened in the lower ends of the expander rods without turning the expander rods. Further, when the tube has a spiral groove formed on its inner surface, it will not rotate and release the rod.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic, perspective view of a vertical tube expander incorporating the improved expander rod mounting structure of this invention;
FIG. 2 is a transverse cross-sectional view through the expander rod mounting structure, the view being taken substantially at the location indicated by arrow II in FIG. 1, with the slide plate being in a position in which the expander rods are locked in the rod-holder plate;
FIG. 3 is a view like FIG. 2, but showing the slide plate and expander rods in a position in which the expander rods can be removed from the rod mounting structure;
FIG. 4 is a sectional view taken along the line IV--IV in FIG. 2;
FIG. 5 is a plan view taken along the line V--V in FIG. 3;
FIG. 6 is a view like FIG. 2 and illustrating a prior art structure; and
FIG. 7 is a fragmentary, schematic illustration of the tube and fin assembly and expander rods, prior to expanding the tubes.
DETAILED DESCRIPTION
Referring to FIG. 7, there is illustrated an assembly of hair-pin tubes T and fins F suitable for being made into a tube and fin-type heat exchanger. The fins F fit loosely on the tubes T. In use of the mechanical tube expander, the expander rods 16, which carry expander bullets 15, are moved through the tubes T so that the tubes are expanded into a tight interlocked relationship with the fins F to provide an integral, permanent assembly thereof and to provide good heat conduction therebetween.
In the following description, reference will be made to expander rods 16. It is to be understood that this term includes both one-piece rods and rods made of a plurality of sections which are releasably joined together in end-to-end relationship.
Referring to FIG. 1, a representative, vertical, tube-expander, on which the present invention can be employed, comprises a frame 10 mounted on a base 11. The tubes T and fins F to be interlocked (not shown in FIG. 1, but illustrated in FIG. 7), are disposed in a container or fixture 12. The tubes are oriented vertically and the fins are loosely stacked thereon. The block 14 supports the reversely curved (hairpin bent) lower ends of the tubes.
A plurality of expander rods 16, corresponding in number and arrangement to the number of tubes, is provided for expanding the tubes. At their lower ends, the expander rods carry expander bullets 15 (FIG. 7) which are effective to expand the tubes into interlocked engagement with the fins when the expander rods are moved vertically downwardly through the tubes. Expander rods 16 extend through guide plates 17 so that the lower ends of the rods are vertically aligned with the tubes. Vertical guide rods 19 are provided for guiding reciprocating movement of the reciprocable parts of the tube expander.
A pressure plate 21 is provided for supporting the expander rods 16 for vertical reciprocating movement. The pressure plate 21 is vertically slidably guided by the rods 19. The pressure plate 21 is connected to the piston rod 22 of the piston and cylinder assembly 23 so that the pressure plate can be moved upwardly and downwardly.
As thus far described, the mechanical tube expander 10 is of conventional structure. The details of its structure and operation are well known and, accordingly, it is believed unnecessary to describe the mechanical tube expander in greater detail. It will be understood that the invention can be employed with a wide variety of different mechanical tube expanders, including ones for expanding hairpin bent tubes and ones for expanding straight tubes, and that the invention is not limited to the specific press illustrated in FIG. 1.
According to the invention, there is provided an improved apparatus 26 for releasably locking the expander rods 16 to the pressure plate 21 so that the expander rods move vertically with the pressure plate and can be released therefrom when necessary for replacement or repair.
The expander rod locking apparatus 26 is here illustrated as being affixed to the lower side of the pressure plate 21, as shown in FIGS. 1 and 2, by means of machine screws 20 (FIG. 2).
The expander rod locking apparatus 26 comprises a slide plate 27 which is adapted to be reciprocated, relative to the pressure plate 21 and rods 16, in a direction lengthwise of the pressure plate and perpendicular to the lengthwise extent of the rods 16. For this purpose, the slide plate 27 slidably contacts the lower surface of the pressure plate 21 and is reciprocated by suitable means, such as a piston and cylinder actuator 28 (FIG. 1). The slide plate 27 is guided for reciprocating movement by a pair of spacer rails 29 which are disposed on opposite lateral sides of the slide plate 27 and slidably engage and guide the side edges of the slide plate 27.
A spring-retainer plate 31 is positioned below the slide plate 27 and the spacer rails 29. The purpose of the spring-retainer plate 31 will be described hereinbelow.
A rod-holder plate 32 is positioned below the spring-retainer plate 31. The rod-holder plate 32 has a plurality of vertical through holes 33 which are arranged in the same pattern and with the same spacing as the expander rods 16. The upper end portions of the expander rods 16 extend vertically upwardly into and through the holes 33 in the rod-holder plate 32, respectively. The expander rods 16 are adapted to be manually rotated about their lengthwise axes and slid vertically in the holes 33, as will be described hereinbelow.
The expander rods 16 each have a concave recess 36 formed in the sidewall thereof close to the upper end thereof. In plan view, as illustrated in FIG. 3 with respect to the righthand rod 16, the recess 36 has a substantially ovate-conical or tear drop shape, with the lengthwise axis thereof being vertical, the narrow conical end being at the upper end thereof and the more rounded, wider end being at the lower end thereof. The lower end portion of the recess 36 is of substantially partially spherical shape for receiving a portion of a ball therein. The recess 36 is of progressively narrower width and progressively shallower depth in a direction toward the upper end of the recess, thereby defining a ramp 37 for leading the ball into the recess 36 when the expander rod 16 is raised relative to the ball, as will be described further hereinbelow.
The reciprocable slide plate 27 has a series of through holes 41 arranged in a number, pattern and spacing corresponding to those of the expander rods 16. The stationary spring retainer plate 31 also has a series of through holes 42 arranged in a number, pattern and spacing corresponding to those of the expander rods 16 and holes 41. The holes 42 are of larger diameter than the holes 33, and the holes 41 are of larger diameter than the holes 42. The upper ends of the expander rod 16 extend into the through holes 42. In one terminal position of the slide plate 27 (FIG. 2 and the broken-line position in FIG. 5), the through holes 41 in the slide plate 27 are out of vertical alignment with the through holes 42 in the spring-retainer plate 31. In this position, the upper ends of the expander rods 16 abut against the lower surface of the slide plate 27. In the other terminal position of the slide plate 27 (FIG. 3 and the solid line position shown in FIG. 5), the respective through holes 41 and 42 are vertically aligned and the expander rods 16 can manually be moved upwardly into the through holes 41 in the slide plate 27 to the position shown in FIG. 3.
The rod-holder plate 32 has an inclined, blind-ended hole 43 associated with each of the through holes 33. The holes 43 open through the upper surface of the rod-holder plate 32 and the upper ends of the holes 43 are closed by the spring-retainer plate 31. The bottom portion of the side wall of the inclined hole 43 intersects and opens through the sidewall of the adjacent associated expander rod-receiving hole 33. A ball 44 is disposed in each hole 43 and is resiliently urged downwardly therein by a compression coil spring 46 which is received in the hole 43. The upper end of the spring 46 engages the lower surface of the spring retainer plate 31. Each of the balls 44 is urged toward the bottom of its associated hole 43 and against the sidewall of its associated expander rod 16. When the recess 36 in the expander rod 16 is vertically and horizontally aligned with the ball 44, the ball extends into the recess as shown in FIG. 2. In the FIG. 2 position of the parts, the expander rods 16 are releasably locked in position.
When it is desired to unlock the expander rods 16 for removing them from the apparatus, the slide plate 27 is moved to the position shown in FIG. 3, wherein the through holes 33, 41 and 42 are in vertical alignment. Then, as shown by the lefthand expander rod 16 in FIG. 3, that expander rod is pushed upwardly so that the recess 36 raises the ball 44 and simultaneously cams it out of the recess 36. Continued upward movement of the expander rod 16 causes the upper end of the expander rod 16 to abut against the lower surface of the pressure plate 21. In this position, the recess 36 is located completely above the ball 44 and is substantially isolated from the hole 43.
Then, as shown by the righthand expander rod in FIG. 3, the expander rod 16 is rotated about its lengthwise axis through a suitable angle, such as from about 90° to 270°, so that the recess 36 is moved out of vertical alignment with its associated ball 44. Then the expander rod 16 can be freely slid downwardly for removing it from the rod-locking apparatus. During the removal of the expander rod 16 it is necessary to slightly rotate the rod while pulling the rod downward. The slight rotation of the rod 16 alleviates the frictional force of the ball 44 against the side of the expander rod, as the spring 46 is still forcing the ball against the side of the expander rod. The replacing of rods is not a reversing of steps as the slide plate 27 must be closed before rods are inserted. The same or a different expander rod 16 can be installed and locked in place by moving the slide plate 27 to its closed position, as illustrated in FIG. 2, followed by substantially the reverse sequence of steps of manipulating the expanding rods.
Although a particular preferred embodiment of the invention has been described, the invention contemplates such changes or modifications therein as lie within the scope of the appended claims.
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A structure is provided for mounting the expander rods of a mechanical tube expander. The mounting structure comprises a slide plate which can be moved between a first position in which the expander rods are in locked condition and a second position in which the expander rods are in unlocked condition.
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BACKGROUND OF INVENTION
[0001] The invention relates generally to gravity-advance conveyors and, more particularly, to inclined rollerways made of modular roller sections for conveying articles down an inclined path.
[0002] Gravity-advance roller conveyors, in which a roller conveyor bed is arranged on an incline, are often used to convey pallets or boxes from high levels to lower levels in warehouses. Because gravity-advance conveyors do not require a drive system, they are less complex than powered-roller conveyors. But, like all conventional metal roller conveyors, powered or not, gravity-advance roller conveyors are noisy when articles are advancing along them. Furthermore, the conveyor frames include mounting holes positioned along the sides to support the ends of the rollers or shafts on which the rollers rotate. Because of the fixed position of the mounting holes in a given conveyor frame, it is difficult to adapt the conveyor frame to accommodate, for example, a change in the orientation of the rollers without extensive rework.
[0003] Thus, there is a need for a conveyor that avoids some of the shortcomings of conventional gravity-advance roller conveyors.
SUMMARY OF INVENTION
[0004] This need and other needs are satisfied by a modular gravity-advance roller conveyor embodying features of the invention. One version of conveyor comprises a mat that is constructed of a plurality of rows of modules. Each row extends longitudinally from a first end to a second end, transversely from a left side to a right side, and in thickness from a top surface to a bottom surface. Each row further includes connecting elements along each end linked with the connecting elements of consecutive rows to form the mat, which extends from an entrance end to an exit end. At least some of the rows have rollers extending above the top surface of the row. A conveyor frame includes an inclined base that supports the mat. The elevation of the entrance end of the mat is higher than the elevation of the exit end. In this way, the weight of an article introduced onto the mat causes the rollers beneath the article to rotate. The rotating rollers move the article down the inclined mat toward the exit end.
[0005] In another version of the invention, a modular gravity-advance roller conveyor comprises a stationary mat, which includes a plurality of modules linked together in rows. At least some of the modules have rollers extending above the top surface of the mat. A conveyor frame includes an inclined base supporting the mat between a higher end and a lower end. The weight of articles introduced onto the mat causes the rollers in contact with the articles to rotate and move the articles toward the lower end of the mat.
[0006] In another aspect of the invention, a modular gravity roller conveyor comprises a conveyor frame with an inclined base. A length of modular plastic roller-top conveyor belt is supported stationarily on the inclined base to form a modular gravity roller conveyor.
[0007] In yet another aspect of the invention, a method for constructing a gravity conveyor comprises providing a conveyor frame with an inclined base and supporting a length of modular roller-top conveyor belt stationarily on the inclined base of the conveyor frame.
BRIEF DESCRIPTION OF DRAWINGS
[0008] The features, aspects, and advantages of the invention are better understood by reference to the following description, appended claims, and accompanying drawings, in which:
[0009] FIG. 1 is an isometric view of a gravity roller conveyor embodying features of the invention;
[0010] FIGS. 2A and 2B are top and bottom isometric views of a cylindrical roller-top module usable in a conveyor as in FIG. 1 ;
[0011] FIG. 3 is an isometric view of a ball-top module useable in a conveyor as in FIG. 1 ;
[0012] FIG. 4 is a schematic representation of a plan view of the gravity roller conveyor of FIG. 1 ; and
[0013] FIGS. 5, 6 , and 7 are schematic representations of plan views of other roller arrangements for gravity conveyors embodying features of the invention.
DETAILED DESCRIPTION
[0014] A conveyor embodying features of the invention is shown in FIG. 1 . The conveyor includes a frame 10 having front legs 12 and longer rear legs 13 supporting a base 14 inclined downwardly from rear to front in FIG. 1 to form a gravity-advance conveyor frame. Wearstrips 16 in the form of transversely spaced longitudinal strips support a conveyor mat 18 . The mat is constructed of a series of rows 20 A-D of modules 22 . Each row extends longitudinally from a first end 24 to a second end 25 , transversely from a right side 26 to a left side 27 , and in thickness from a top surface 28 to a bottom surface 29 . Connecting elements 30 that are spaced apart along the ends of each row interleave with the connecting elements of adjacent rows. A connecting pin 32 extending through a passageway formed by aligned transverse apertures 34 through the connecting elements connects adjacent rows together. Pins 36 through the apertures of the uppermost and lowermost connecting elements of the mat are retained at their ends in retainers 38 on the frame to secure the mat in place. The mat can be easily constructed from a length of modular plastic conveyor belt, such as the roller-top versions of the Series 400 belt manufactured and sold by Intralox, Inc., of Harahan, La., USA. Although a single mat is shown, the conveyor could be constructed of a number of abutting or closely spaced individual mats, and the term “mat” refers to both constructions.
[0015] The mat shown in FIG. 1 is constructed of roller-top modules 40 , 41 , 42 . The center modules 40 have rollers 44 that are arranged to rotate about transverse axes 46 . The rollers in the left-side modules 41 rotate about first axes 48 oblique to the transverse direction. The rollers in the right-side modules 42 rotate about second axes 49 oblique to the transverse direction and mirroring the first axes about the centerline of the mat. At least a portion of each roller extends above the top surface of the mat to engage the undersides of articles 50 introduced onto the conveyor. Because of the incline, the weight of the articles on the rollers causes the rollers in contact with the articles to rotate and direct the articles in a direction generally perpendicular to the roller axes. An outer portion of each roller could, but does not have to, extend beyond the bottom surface of the mat. If the rollers do extend beyond the bottom surface of the mat, they are preferably arranged in transversely spaced longitudinal lanes so that the mat can be positioned on the supporting wearstrips with the strips between the roller lanes to avoid interfering with the rotation of the rollers. If the rollers do not extend outward of the bottom surface, other wearstrip patterns can be used.
[0016] In the example conveyor of FIG. 1 , the angled roller arrangement on the left side urges articles entering the upper entrance end 43 of the mat toward the right, and the oppositely angled roller arrangement on the right side urges articles towards the left. As articles reach the center of the mat, the central rollers that rotate about transverse axes direct the articles straight down the conveyor and off the lower exit end 45 of the mat. Thus, the conveyor of FIG. 1 acts as a gravity-advance centering roller conveyor by directing articles toward the center of the conveyor.
[0017] A typical angled roller-top belt module that could be used as a left-side module in the conveyor of FIG. 1 is shown in FIGS. 2A and 2B . The module 52 has a flat top surface 54 and an opposite bottom surface 55 . Cylindrical rollers 56 are rotatably mounted in cavities 58 that open onto the top surface and the bottom surface. The rollers rotate on axles 60 retained in the interior of the module. Connecting elements 62 along each end of the module include aligned apertures 64 for receiving connecting pins to interconnect modules together. A module usable in the center or in right side of the conveyor of FIG. 1 would be similarly formed, but with the orientation of the rollers appropriately arranged. The module bodies are preferably formed by injection molding out of thermoplastic materials such as polyethylene, polypropylene, acetal, and composite resins, for example.
[0018] Instead of using modules with cylindrical rollers that rotate about fixed axes, the conveyor of FIG. 1 could use modules 66 with universally rotatable ball rollers 68 , as shown in FIG. 3 . The module is similar to that of FIG. 2 , but includes a round cavity 70 opening onto the top surface 72 . The roller ball is confined in the round cavity with a salient portion of the ball extending above the top surface of the module. The module is further shown with openings 74 through the module body for drainage, airflow, or weight reduction. These ball-top modules are usable, for example, as the central modules in FIG. 1 .
[0019] The spherical and cylindrical rollers described in detail with respect to FIGS. 2 and 3 are just two examples of the types of rollers that can be used in a conveyor as in FIG. 1 . Because of the modularity of modular plastic conveyor belts, it is easy to reconfigure a mat constructed of plastic modules to accommodate changing conveyor requirements. The centering conveyor of FIG. 1 is represented functionally by FIG. 4 , which is a plan view of the conveyor mat. The arrows indicate the direction in which articles move as they make their way down the conveyor. The arrows are directed generally perpendicular to the axes of rotation of the rollers in that portion of the conveyor mat. Consequently, the schematic representation of FIG. 4 corresponds to the physical arrangement of FIG. 1 . The conveyor mat 18 in FIG. 4 is divided transversely into three longitudinal lanes 76 , 77 , 78 . The rollers in the left lane 76 and the right lane 78 are arranged to direct articles toward the center of the mat. The rollers in the center lane 77 direct articles straight down the conveyor mat. Thus, FIG. 4 represents a centering conveyor.
[0020] FIG. 5 represents another centering conveyor made with a modular mat 79 . In this example, the conveyor mat uses right- and left-side angled roller-top modules arranged in lanes 76 , 78 similar to those represented in FIG. 4 . But, unlike the mat represented by FIG. 4 , this centering conveyor mat does not include a central lane of rollers directing articles straight down the conveyor mat. Instead, articles directed toward the center are allowed to wander slightly back and forth about the centerline of the mat as they advance down the conveyor.
[0021] Another conveyor that can easily be constructed of modular components is represented in FIG. 6 . In this example, the conveyor can serve to align articles along the outside edges of the conveyor (if a side rail or guard is in place) or to transfer articles off the side edges (if no obstruction is in place at the side). The conveyor includes a mat 80 divided transversely into two longitudinal lanes 82 , 83 . The rollers in the left lane 82 are arranged obliquely to direct articles toward the left side of the conveyor. The rollers in the right lane 83 are arranged to direct articles toward the right side of the conveyor.
[0022] Yet another conveyor that can be constructed out of roller-top belt modules is represented by FIG. 7 . This conveyor includes a mat 84 divided longitudinally into two transverse portions 86 , 87 . The rollers in the upper portion 86 are oriented to direct articles toward the right side of the conveyor mat. The rollers in the lower portion 87 are arranged to direct articles straight down the conveyor. In this way, the conveyor represented by FIG. 7 moves articles toward the right side before advancing them off the lower exit end.
[0023] As these few examples suggest, a modular roller-top conveyor mat can be easily reconfigured and placed in a gravity-advance roller conveyor frame to accommodate a wide variety of conveying requirements. The modularity allows readily available modules with rollers capable of rotating about a range of axes to be connected together in a pattern, even with non-roller-top modules, to form a custom conveyor mat. It should further be clear that, although the conveyor mats described in detail were laid out in the conveyor frame with connecting pins transverse to the gradient of the incline, the conveyor mats could be laid out on an inclined conveyor frame with connecting pins along or oblique to the gradient. Because it is impossible to describe all the possible patterns and arrangements, the scope of the invention is not meant to be limited to the specific versions described in detail.
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A modular gravity-advance roller conveyor for conveying articles down an inclined path. The conveyor comprises an easy-to-configure modular conveyor mat supported in a conveyor frame with an inclined base. The conveyor mat is constructed of a series of rows of roller-top modules with rollers that extend above the top surface of the mat. Connecting elements along the ends of each row are connected to the connecting elements of adjacent rows to form the mat. The rollers on a roller-top module rotate about an axis of rotation. Modules with rollers that rotate about a given axis of rotation can be combined with modules with rollers that rotate about a different axis of rotation in a variety of patterns to meet common or special conveying requirements.
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FIELD OF THE INVENTION
[0001] This patent application relates to production of organic acids from glycerol by fermentation using genetically engineered microorganisms.
BACKGROUND OF THE INVENTION
[0002] Large scale processes have been developed and are being used commercially to convert glycerol esters of fatty acids (also known as glycerides, mono-glycerides, di-glycerides, and tri-glycerides) to glycerol esters of methanol, ethanol, or other alcohols. The resulting fatty acid esters (also known as FAME for fatty acid methyl ester or FAEE for fatty acid ethyl ester) are commonly known as “biodiesel”, because they can be used by themselves or in blends with conventional hydrocarbons as fuel for diesel engines. The raw materials for the synthesis of biodiesel can include vegetable oil, animal fats, and discarded cooking oil. A major volume byproduct of the biodiesel process is glycerol (also known as glycerin or glycerine). For each kilogram of biodiesel produced, about 0.1 kilogram of glycerol byproduct is produced.
[0003] When the catalyst for biodiesel synthesis is sodium hydroxide or potassium hydroxide, the glycerol byproduct is typically about 80% to 90% glycerol by weight, with the remainder of the byproduct being mostly water, methanol or ethanol (depending on which alcohol was used for the transesterification), various salts, and low levels of other organic compounds. The raw glycerol byproduct is alkaline and viscous, so it is usually neutralized down to a pH of about 4 or 5 with sulfuric acid, hydrochloric acid, or other acid, which reduces the viscosity and leaves the presence of the resulting salts, such as sodium chloride, sodium sulfate, potassium chloride, potassium sulfate, etc., with the exact composition obviously depending on the compounds used in the process. Much or all of the alcohol can typically be removed and recovered from the crude glycerol by distillation. The sodium or potassium hydroxide catalyst used in this type of process is called a homogeneous catalyst.
[0004] Another process for producing biodiesel relies on a “heterogeneous catalyst”. An example of this is called Esterfip-H, commercialized by the French company Axens. The exact nature of this catalyst is proprietary, but it is reported to be a spinel mixed oxide of two non-noble metals, and it is reported to give a much cleaner glycerol byproduct than that from a homogeneous catalyst. The glycerol byproduct from a heterogeneous catalyst is reported to be 98% pure and free of salts (Ondrey, 2004).
[0005] With the growth of the biodiesel business there has of necessity been a parallel growth in the volume of glycerol byproduct. Some of the crude glycerol byproduct from biodiesel industry is purified by distillation and used in various industries that have classically used glycerol as a feedstock, and the rest of the glycerol from the biodiesel industry is considered to be a burdensome waste product. As a result, the value of the crude glycerol has plummeted to $0.05/lb or less in recent years (De Guzman, 2010). As such, glycerol has become a potentially inexpensive alternative to sugars and other carbohydrates such as glucose, fructose, sucrose, maltose, starch, and inulin, as a fermentation feedstock for production of fuels and chemicals (Clomburg and Gonzalez, 2010; Yazdani and Gonzalez, 2007). As of this writing, glucose and sucrose cost about $0.15 to $0.25/lb, and therefore a fermentation process that can use glycerol instead of other sugars could result in a substantial economic advantage.
[0006] A number of microorganisms have been developed for the commercial production of useful chemicals via fermentation using renewable sugars. Escherichia coli ( E. coli ) strains capable of producing organic acids in significant quantities using a variety of sugars as the source of carbon are well known in the art. For example, the U.S. Patent Application Publication No. 2009/0148914 provides strains of E. coli as a biocatalyst for the production of chemically pure acetate and/or pyruvate. The U.S. Pat. No. 7,629,162 provides derivatives of E. coli KO11 strain constructed for the production of lactic acid. International Patent Application Nos. WO 2008/115958 and WO 2010/115067 published under the Patent Cooperation Treaty provide microorganism engineered to produce succinate and malate in a minimal salt medium containing glucose as a source carbon in pH-controlled batch fermentation. U.S. Pat. No. 7,241,594 and U.S. Pat. No. 7,470,530 and the International Patent Application Publication No. WO 2009/024294 provides rumen bacterium Mannheimia succiniproducens useful in the fermentative production of succinic acid using sugars as the source of carbon. U.S. Pat. Nos. 5,000,000, 5,028,539, and 5,424,202 provide E. coli strains for the production of ethanol. U.S. Pat. Nos. 5,482,846, 5,916,787, and 6,849,434 provide gram-positive microbes for ethanol production. U.S. Pat. No. 7,098,009 provides Bacillus strains for the production of L(+) lactic acid. U.S. Pat. Nos. 7,223,567, 7,244,610, 7,262,046, and 7,790,416 provide E. coli strains for the production of succinic acid.
[0007] Most of the microbial organisms currently used in the biotechnology industry for the production of fuels and chemicals have a dedicated metabolic pathway for glycerol utilization. However, none of these industrial microorganisms have ever been shown to have the capacity to use glycerol as a feedstock with production parameters that are attractive for commercial manufacturing. This inability of the industrial microorganism to utilize glycerol as a commercial feedstock in the manufacturing of useful chemicals is attributed to certain regulatory metabolic feedback control mechanisms that are operational within the microbial cells.
[0008] The uptake and metabolism of glycerol by microorganisms has been well studied, particularly in Escherichia coli (Lin, 1996; Gonzalez et al., 2008). As shown in FIG. 1 , in E. coli , glycerol enters the cell by a facilitated diffusion protein encoded by the glpF gene. In the “classical” glycerol metabolic pathway, glycerol is phosphorylated by glycerol kinase, encoded by the glpK gene, to give glycerol-3-phosphate (G3P). The G3P is then reduced to dihydroxyacetone phosphate by either the G3P dehydrogenase encoded by glpD or the three-subunit G3P dehydrogenase encoded by glpABC. The GlpK-GlpD/GlpABC pathway is considered to be respiratory route as it requires electron acceptors and is believed to be operational under aerobic conditions or when an alternative electron acceptor is present, such as nitrate or fumarate.
[0009] Another pathway for glycerol metabolism within the microbial cell is referred to as the non-classical pathway and is thought to be operational under anaerobic conditions (Gonzalez et al., 2008). In this second pathway, glycerol transported into the cell is reduced to dihydroxyacetone by a glycerol dehydrogenase encoded by gldA. The dihydroxyacetone is then phosphorylated by a phosphoenolpyruvate-dependent dihydroxyacetone kinase encoded by dhaKLM. The dihydroxyacetone phosphate resulting from either of these pathways can enter into the glycolytic pathway through triose phosphate isomerase, encoded by tpi. Triosephosphate isomerase converts dihydroxyacetone phosphate into glyceraldehyde-3-phosphate which can enter into the tricarboxylic acid pathway after conversion into glycerate-1,3-diphosphate which in turn is converted into phosphoenolpyruvate.
[0010] There are several reports that disclose microbial production of various compounds by fermentation from glycerol. In general, the chemicals produced via microbial fermentation from glycerol, including succinate, ethanol, 1,2-propanediol, hydrogen, and formate, are produced at titers that do not appear to be high enough to compete with other known commercial processes for producing those compounds (Gonzalez et al., 2008; Durnin et al., 2009; Yazdani and Gonzalez, 2008).
[0011] Blankenschein et al. (2010) described an engineered E. coli strain that is contains ΔadhE, Δpta, ΔpoxB, ΔldhA, Δppc, and a plasmid pZS-pyc that over-expresses pyruvate carboxylase from Lactococcus lactis . Preliminary experiments with GldA-DhaKLM expressed from a separate vector in the ΔadhE, Δpta, ΔpoxB, ΔldhA, Δppc, [pZS-pyc] stain showed no improvements in succinate production. There are certain disadvantages with this glycerol utilizing strain of E. coli . This strain, which was not given a specific name, produced only 14 g/l of succinate in 72 hours with a yield of 0.69 g/g glycerol. Moreover, the plasmid pZS-pyc requires chloramphenicol for maintenance and anhydrotetracycline for induction, both of which are undesirable for large scale fermentations.
[0012] Yazdani and Gonzalez (2008) describe two E. coli strains, SY03 and SY04, designed to produce ethanol plus hydrogen or formate, respectively. These two strains also require the plasmid pZSKLMGldA. This plasmid is designed to over express the E. coli dhaKLM operon and gldA, which presumably increases flux through the “non-classical” glycerol pathway. In the most favorable example given, SY04 containing pZSKLMGldA produced about 10 g/l ethanol and 9 g/l formate from about 22 g/l glycerol, in 100 hours. These fermentation parameters are not high enough for a competitive commercial process. Moreover, the pZSKLMGldA plasmid requires chloramphenicol for maintenance and anhydrotetracycline for induction, both of which are undesirable for large scale fermentations.
[0013] The International Patent Application Publication No. WO 2010/051324 discloses E. coli strains with the plasmids LA01 (pZSglpKglpD) and LA20 (pZSglpKglpD) overexpressing glpK and glpD genes to produce D-lactate and L-lactate, respectively.
[0014] Zhang et al. (2010) have described an engineered E. coli strain, XZ721, that contains a mutation in the promoter region of pck gene (called pck*), ΔptsI, and ΔpflB. In fermentors, strain XZ721 using glycerol as a source of carbon produced 12 g/l succinate in 6 days, with a yield of 0.80 mol/mol glycerol used, which is equivalent to 1.02 g/g glycerol used. Deletion of gldA or dhaM in the pck* background led to higher succinate titers (13.2 g/l and 12.7 g/l respectively), suggesting that the GldA-DhaKLM route might not be the preferred pathway for succinate production under the fermentation conditions used.
[0015] Scholten et al. have recently isolated a novel ruminant bacterium in the Pasteurellaceae family that was named DD 1 or Basfia succiniciproducens . The DD 1 bacterium produces succinate from glycerol anaerobically (US Patent Application 2011/0008851). However, Basfia succiniciproducens does not grow on a minimal medium without added nutrients, and the maximum reported titer was 35 g/l succinate from glycerol as the sole carbon source. If maltose was added to the medium, the titer was improved to 58 g/l, but a significant amount of glycerol remained unused.
[0016] Trinh and Srienc (2009) reported improving the production of ethanol from glycerol by using elementary mode analysis to design an optimal E. coli strain. The optimal strain, TCS099 was then constructed, with a genotype of Δzwf, Δndh, ΔsfcA, ΔmaeB, ΔldhA, ΔfrdA, ΔpoxB, Δpta, and Δmdh. After metabolic evolution, TCS099 containing a plasmid, pLOI297, which expressed Zymomonas mobilis ethanol production genes, was able to produce ethanol from glycerol at up to 97% of theoretical yield and titer of about 17 g/l from 40 g/l glycerol. However, this process would again not be economically competitive with other current processes. The authors pointed out that mutations in glycerol kinase can increase the specific growth rate of strains on glycerol, as was known in 1970 (Zwaig et al., 1970), and they suggested that their evolved strain might have generated an increase in flux through glycerol kinase through a mutation, but they did not sequence or characterize the glycerol kinase gene in their evolved strain, and they did not suggest that deliberate introduction of a mutated glycerol kinase would increase rate of ethanol production or lead to a higher ethanol titer with glycerol as the source of carbon.
[0017] Since the industrial scale microbial production of biofuels and organic chemicals is carried out under anaerobic fermentative conditions, it is logical to activate the anaerobic glycerol utilization pathway inside the microbial cell in order to make the microorganisms to utilize glycerol as the feedstock. But as described above, the genetic manipulation of the anaerobic glycerol utilization pathway has not produced expected improvements in the production of desired chemicals using glycerol as the sole source of carbon. There has been disclosures in the prior art of feedback resistant alleles of glpK and of regulation of expression of glycerol utilization genes in the aerobic glycerol utilization pathway by the repressor protein coded by glpR gene. However, no effort has ever been made to improve the production of commercially useful chemicals from glycerol by replacing the wild type glpK allele in a production strain with a feedback resistant glpK allele or by deleting the repressor of glycerol utilization, such as the E. coli glpR gene, or a combination of the two approaches. The present inventors have surprisingly found out that by means of engineering the GlpK-GlpD/GlpABC route for glycerol utilization followed by a process of metabolic evolution in the microbial cells selected for the production of succinic acid, it is possible to confer the ability to utilize glycerol as the source of carbon, while retaining the original production capacity for succinic acid. Although the present invention is explained in detail with the construction of an E. coli strain suitable for the commercial production of succinic acid using glycerol as the source of carbon, the general theme and the spirit of the present invention can be applied in the construction of the microbial strains for the production of a number of other commercially useful chemicals using glycerol as the source of carbon in a microbial fermentation process.
SUMMARY OF THE INVENTION
[0018] The present invention provides microorganisms and the processes for the production of one or more chemicals of commercial interest through biological fermentation using glycerol as a carbon source. Using glycerol as a source of carbon and the microorganisms and the processes of the present invention, one can manufacture a variety of chemicals of commercial interest including but not limited to succinic acid, lactic acid, malic acid, fumaric acid, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, ethanol and acetic acid.
[0019] In a preferred embodiment, the glycerol suitable for the present invention is derived from the biodiesel industry. In a most preferred embodiment, the present invention uses glycerol derived from the biodiesel industry from which contaminating compounds have been removed. In one aspect, the glycerol derived from biodiesel industry is free of contaminating compounds such as methanol and ethanol. In another aspect of the present invention, the glycerol derived from the biodiesel industry is free of contaminating ions including but not limited to sodium, potassium, calcium, magnesium, ammonium, chloride, sulfate, phosphate, and mixtures thereof.
[0020] In another embodiment, the present invention provides a microorganism suitable for the manufacture of one or more chemicals of commercial interest using glycerol as a source of carbon wherein said microorganism comprises a deregulated glycerol utilization pathway and the glycerol utilization pathway comprises a facilitated diffuser, a glycerol kinase, and glycerol-3-phosphate dehydrogenase.
[0021] In one aspect of the present invention, deregulation of the glycerol utilization pathway involves a mutation in a glpR gene or other regulatory gene that results in a substantial decrease in the activity of a repressor that negatively regulates expression of glycerol utilization genes.
[0022] In another aspect of the present invention, deregulation of glycerol utilization pathway involves replacing the promoter region of the glpK, glpF, glpD and glpABC genes with the DNA sequence that would act as a constitutive promoter
[0023] In yet another embodiment, the present invention provides microorganisms for the production of one or more chemicals of commercial interest using glycerol as a source of carbon, wherein the microorganisms have a mutation in a glpK gene or other gene encoding a glycerol kinase which confers resistance to feedback inhibition.
[0024] In one aspect, the present invention provides a microorganism comprising a mutation in a glpK gene that causes the specific activity of glycerol kinase to be substantially resistant to inhibition by fructose-1,6-bisphospate.
[0025] In another aspect, the present invention provides a microorganism comprising a mutation in a glpK gene that causes the specific activity of glycerol kinase to be substantially resistant to inhibition by a non-phosphorylated Enzyme IIA Glc of a phosphotransferase system.
[0026] In yet another aspect, the present invention provides microorganisms comprising two or more mutations, one of which causes the activity of a repressor that negatively regulates expression of glycerol utilization genes to be substantially decreased, and another of which causes the specific activity of a glycerol kinase to be substantially resistant to inhibition by fructose-1,6-bisphosphate and/or by a non-phosphorylated Enzyme IIA Glc of the phosphotransferase system.
[0027] In another embodiment, the present invention provides a method for producing one or more chemicals of commercial interest using glycerol as a source of carbon, wherein the method comprises microaeration.
[0028] In one aspect, the present invention provides a method for producing chemicals of commercial interest using glycerol as a source of carbon, wherein the fermentation broth is provided with less than 0.15 liters of oxygen per liter of broth per minute.
[0029] In another aspect, the present invention provides a method for producing chemicals of commercial interest using glycerol as a source of carbon wherein the fermentation broth is provided with at least 20 mg of oxygen per liter of broth per hour.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 Metabolic pathway for glycerol utilization in microorganisms. Glycerol import from the external environment into the microbial cell is mediated by a facilitated diffusion protein coded by glpF gene. Once within the cell, the glycerol can be metabolized to dihydroxyacetone phosphate. One of the two pathways considered to be operational under anaerobic conditions involves the proteins coded by gldA and dhaKLM genes. This pathway is shown by broken lines in the illustration. The other pathway for glycerol metabolism within the microbial cell is generally considered to be active under aerobic conditions, or when an alternative electron acceptor such as nitrate or fumarate is present, and is referred to as the classical pathway for glycerol utilization. The classical pathway for glycerol utilization within the microbial cell is shown by continuous line in the illustration. The genes glpF, glpK, glpD and glpABC code for the proteins involved in the operation on the classical pathway. Not shown in the figure is the glpX gene, which is in an operon together with glpF and glpK (the glpFKX operon), and which encodes a fructose-1,6-bisphosphate phosphatase that contributes to gluconeogenesis when the cell is growing on glycerol. Also shown in the figure are the regulatory mechanisms controlling the proteins involved in the operation of the classical pathway for glycerol metabolism. The repressor protein coded by the glpR gene controls the transcription of the glpFKXX, glpABC and glpD genes/operons. The glycerol kinase coded by glpK gene is also subjected to feedback inhibition by fructose-1,6-bisphosphate (FBP) and by the unphosphorylated form of EIIA glc , a component of the phosphotransferase sugar transport system. Dihydroxyacetone phosphate, the end product of glycerol metabolism is converted into glyceraldehyde-3-phosphate through the action of triose phosphate isomerase coded by the tpi gene. Glyceraldehyde-3-phosphate acts as the starting point for the production of biofuels and organic acids within the microbial cells.
[0031] FIG. 2 Construction of glycerol utilizing RY819J-T14 strain from KJ122 E. coli strain. This illustration provides steps followed in the construction of an E. coli strain RY819J-T14. In the first stage of the construction of RY819J-T14, the wild type glpK gene in the KJ122 strain was replaced with a mutant form of glpK gene containing two point mutations leading to two amino acid substitutions. In the second stage, the glpR gene is inactivated with the insertion of a kanamycin resistant gene cartridge leading to the generation of the RY819J strain of E. coli . In the third stage, the RY819J strain of E. coli is subjected to metabolic evolution to obtain the RY819J-T14 strain of E. coli . Metabolic evolution of RY819J to obtain RY819J-T14 involved fourteen transfers as described in the specification.
[0032] FIG. 3 Construction of glycerol utilizing E. coli strain MH28. DNA sequencing in the glpFK region of the RY819J-T14 strain of E. coli obtained at the end of metabolic evolution revealed two amino acid substitutions (Ala 55 Thr; Arg 157 His) within the open reading frame of glpK gene and one amino acid substitution (Pro 274 Leu) within the open reading frame of glpF gene. The mutation within glpF region was cured through a two-step process. In the first step, the glpF gene with the amino acid substitution (Pro 274 Leu) was inactivated with the insertion of a cat-sacB gene cartridge. In the next step, the cat-sacB gene cartridge was replaced by a wild type glpF gene sequence leading to the generation of MH28 strain of E. coli strain. The three mutations found in glpF and glpK were also found in the donor strain BB14-20.
[0033] FIG. 4 A representative HPLC profile for a fermentation broth containing succinic acid. The fermentation broth obtained from the MH28 strain of E. coli strain grown in a medium containing nominally 10% (w/w) of glycerol was processed according to the procedure described in the specification. The processed sample was run on HPLC equipment fitted with a BioRad Aminex HPX-87H column (see Example 2).
[0034] FIG. 5 Kinetics of glycerol utilization by the KJ122 strain of E. coli . The KJ122 strain was grown in a minimal medium with 10% (w/w) glycerol in a 7 L fermentor under microaerobic condition as described in the specification. The fermentor was run for a period of 52 hours and the glycerol consumption as well as the accumulation of succinic acid, pyruvic acid, and acetic acid were monitored using an HPLC apparatus as described in the specifications.
[0035] FIG. 6 Kinetics of glycerol utilization by the MH28 strain of E. coli . The MH28 strain was grown in a minimal medium with 10% (w/w) glycerol in a 7 L fermentor under microaerobic condition as described in the specification. The fermentor was run for a period of 52 hours and the glycerol consumption as well as the accumulation of succinic acid, fumaric acid, pyruvic acid, and acetic acid were monitored using an HPLC apparatus as described in the specifications.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] A number of industrially useful chemicals of commercial interest can be manufactured using the present invention. Most of these chemicals of commercial interest are intermediates in microbial metabolism. In the present invention, the microbial genome and growth conditions are appropriately manipulated to produce one or more of these microbial intermediates in significant quantities in a commercially successful way. Examples of such chemicals include, but are not limited to, ethanol, butanols, lactate, succinate, fumarate, malate, threonine, methionine and lysine. Since organic acids can exist both as free acids and as salts (for example, but not limited to, salts of sodium, potassium, magnesium, calcium, ammonium, etc.). Chemical names such as succinic acid, fumaric acid, malic acid, aspartic acid, threonine, methionine, and lysine shall be meant to include both the free acid and any salt thereof. Likewise, any salt, such as succinate, fumarate, malate, aspartate, etc., shall be meant to include the free acid as well.
[0037] The present invention combines the technique of specific genetic modifications with the process of metabolic evolution to obtain strains showing high yield, titer and volumetric productivity for succinic acid production under anaerobic or microaerobic growth conditions in a mineral salt medium with a glycerol as a carbon source.
[0038] For the purpose of the description of the present invention, the following definitions shall be used.
[0039] As used in the present invention, the term “titer” means the gram per liter or molar concentration of particular compound in the fermentation broth. Thus in the fermentation process for the production of succinic acid according to the present invention, a succinic acid titer of 100 mM would mean that the fermentation broth at the time of measurement contained 100 mMoles per liter or 11.8 grams per liter (g/l) of succinic acid in the fermentation broth.
[0040] As used in the present invention, the term “yield” refers to the moles of a particular compound produced per mole of the carbon source consumed during the fermentation process, or the grams of a particular compound produced per gram of carbon source consumed during the fermentation process. Thus in the fermentative process for the production of succinic acid using glycerol as a carbon source, the term yield refers to the number of grams of succinic acid produced per gram of glycerol consumed.
[0041] As used in the present invention, the term “volumetric productivity” refers to the amount of particular compound in grams produced per unit volume per unit time. Thus a volumetric productivity value of 0.9 g L −1 h −1 for succinic acid would mean that 0.9 gram succinic acid is accumulated in one liter of fermentation broth during an hour of growth.
[0042] As used in the present invention, the term “gene” includes the open reading frame or frames of a DNA sequence as well as the upstream and downstream regulatory sequences. The upstream regulatory region is also referred as the promoter region of the gene. The downstream regulatory region is also referred as the terminator sequence region.
[0043] The phrase “functionally similar” means broadly any wild type or mutated DNA sequence, gene, enzyme, protein, from any organism, that has a biological function that is equivalent or similar to any wild type or mutated DNA sequence, gene, enzyme, protein that is found in the same or a different organism by the methods disclosed herein. Functional similarity need not require sequence homology. An allele is one of two or more forms of DNA sequence of a particular gene. Through mutations, each gene can have different alleles. A gene without any mutation is referred as a wild type allele when compared to a corresponding gene that has a mutation.
[0044] A homolog is a gene related to a second gene by descent from a common ancestral DNA sequence. The term, homolog, may apply to the relationship between genes separated by the event of speciation or to the relationship between genes separated by the event of genetic duplication. Orthologs are genes in different species that evolved from a common ancestral gene by speciation. Normally, orthologs retain the same function in the course of evolution. Identification of orthologs is critical for reliable prediction of gene function in newly sequenced genomes. Speciation is the origin of a new species capable of making a living in a new way from the species from which it arose. As part of this process it has also acquired some barrier to genetic exchange with the parent species. Paralogs are genes related by duplication within a genome. Orthologs retain the same function in the course of evolution, whereas paralogs evolve new function, even if these are related to the original one.
[0045] A gene or protein with “altered activity” is broadly defined as gene or protein that produces a measurable difference in a measurable property when compared to the relevant wild type gene or protein. The altered activity could manifest itself in a general way by increasing or decreasing the growth rate or efficiency of succinate production of the strain containing the altered gene or protein. Other measurable properties include, but are not limited to enzyme activity, substrate specificity of an enzyme, kinetic parameters of an enzyme such as affinity for a substrate or rate, stability of an enzyme, regulatory properties of an enzyme, gene expression level, regulation of gene expression under various conditions, sensitivity to one or more inhibitors, etc.
[0046] As used in the present invention, the term mutation refers to genetic modifications done to the gene including the open reading frame, upstream regulatory region and downstream regulatory region. A gene mutation can result either in an up regulation or a down regulation or complete inhibition of the transcription of the open reading frame of the gene or a change in the activity of the protein encoded by the mutated gene. The gene mutations can be achieved either by deleting the entire coding region of the gene or a portion of the coding nucleotide sequence or by introducing a frame shift mutation, a missense mutation, and insertion, or by introducing a stop codon or combinations thereof. Mutations may occur in the structural genes coding for the proteins directly involved in the biological functions such as enzyme reactions or transport of the organic molecules across the cell membrane. Alternately, mutations may occur in the regulatory genes coding for the proteins which control the expression of the genes coding for the proteins directly involved in the biological functions. The proteins which control the expression of the other genes are referred as regulatory proteins and the genes coding for these regulatory proteins are referred as regulatory genes.
[0047] “Mutation” shall also include any change in a DNA sequence relative to that of the relevant wild type organism. For example, a mutation found in strain KJ122 is any change in a DNA sequence that can be found when the DNA sequence of the mutated region is compared to that of the parent wild type strain, E. coli C, also known as ATCC 8739. A mutation can be an insertion of additional DNA of any number of base pairs or a deletion of DNA of any number of base pairs. A particular type of insertion mutation is a gene duplication. A gene can be duplicated by a spontaneous mutational event, in which the second copy of the gene can be located adjacent to the original copy, or a gene can be duplicated by genetic engineering, in which the second copy of the gene can be located at a site in the genome that is distant from the original copy. A mutation can be a change from one base type to another base type, for example a change from an adenine to a guanine base. In the vernacular of genetics, a mutation can be a missense (which changes the amino acid coded for by a codon), a nonsense (which changes a codon into stop codon), a frameshift (which is an insertion or deletion of a number of bases that is not a multiple of three and which changes the reading frame and alters the amino acid sequence that is encoded downstream from the mutation, and often introduces a stop codon downstream from the mutation), or an inversion (which results from a DNA sequence being switched in polarity but not deleted). The symbol “Δ” in front of the name of a gene indicates that the coding sequence for that gene has either fully or partially been eliminated and the gene is functionally inactive.
[0048] A “null mutation” is a mutation that confers a phenotype that is substantially identical to that of a deletion of an entire open reading frame of the relevant gene, or that removes all measurable activity of the relevant gene.
[0049] A “mutant” is a microorganism whose genome contains one or more mutations.
[0050] As used in this invention, the term “exogenous” is intended to mean that a molecule or an activity derived from outside of a cell is introduced into the host microbial organism. In the case an exogenous nucleic acid molecule introduced into the microbial cell, the introduced nucleic acid may exist as an independent plasmid or may get integrated into the host chromosomal DNA. The exogenous nucleic acid coding for a protein may be introduced into the microbial cell in an expressible form with its own regulatory sequences such as promoter and terminator sequences. Alternatively, the exogenous nucleic acid molecule may get integrated into the host chromosomal DNA and may be under the control of the host regulatory sequences. The term “endogenous” refers to the molecules and activity that are present within the host cell. When used in reference to a biosynthetic activity, the term “exogenous” refers to an activity that is introduced into the host reference organism. The source can be, for example, a homologous or heterologous encoding nucleic acid that expresses the referenced activity following introduction into the host microbial organism. If the nucleic acid coding for a protein is obtained from the same species of the microbial organism, it is referred to as homologous DNA. If the nucleic acid derived from a different microbial species, it is referred to as heterologous DNA. Irrespective of the nature of the DNA, whether it is homologous or heterologous, when introduced into a host cell, the DNA as well as the activity derived from that introduced DNA is referred to as exogenous. Therefore, exogenous expression of an encoding nucleic acid of the invention can utilize either or both heterologous and homologous encoding nucleic acid.
[0051] The present invention provides microorganisms that can use glycerol as a source of carbon in the manufacturing of commercially useful chemicals. Although the present invention is demonstrated using Escherichia coli bacterium, this invention can be applied to wide range of bacterial species including Citrobactor freundii, Gluconobacter oxydans, Gluconobacter asaii, Achromobacter delmarvae, Achromobacter viscosus, Achromobacter lacticum, Agrobacterium tumefaciens, Agrobacterium radiobacter, Alcaligenes faecalis, Arthrobacter citreus, Arthrobacter tumescens, Arthrobacter paraffineus, Arthrobacter hydrocarboglutamicus, Arthrobacter oxydans, Aureobacterium saperdae, Azotobacter indicus, Brevibacterium ammoniagenes, divaricatum, Brevibacterium lactofermentum, Brevibacterium flavum, Brevibacterium globosum, Brevibacterium fuscum, Brevibacterium ketoglutamicum, Brevibacterium helcolum, Brevibacterium pusillum, Brevibacterium testaceum, Brevibacterium roseum, Brevibacterium immariophilium, Brevibacterium linens, Brevibacterium protopharmiae, Corynebacterium acetophilum, Corynebacterium glutamicum, Corynebacterium callunae, Corynebacterium acetoacidophilum, Corynebacterium acetoglutamicum, Enterobacter aerogenes, Erwinia amylovora, Erwinia carotovora, Erwinia herbicola, Erwinia chrysanthemi, Flavobacterium peregrinum, Flavobacterium fucatum, Flavobacterium aurantinum, Flavobacterium rhenanum, Flavobacterium sewanense, Flavobacterium breve, Flavobacterium meningosepticum, Micrococcus sp. CCM825, Morganella morganii, Nocardia opaca, Nocardia rugosa, Planococcus eucinatus, Proteus rettgeri, Propionibacterium shermanii, Pseudomonas synxantha, Pseudomonas azotoformans, Pseudomonas fluorescens, Pseudomonas ovalis, Pseudomonas stutzeri, Pseudomonas acidovolans, Pseudomonas mucidolens, Pseudomonas testosteroni, Pseudomonas aeruginosa, Rhodococcus erythropolis, Rhodococcus rhodochrous, Rhodococcus sp. ATCC 15592, Rhodococcus sp. ATCC 19070 , Sporosarcina ureae, Staphylococcus aureus, Vibrio metschnikovii, Vibrio tyrogenes, Actinomadura madurae, Actinomyces violaceochromogenes, Kitasatosporia parulosa, Streptomyces coelicolor, Streptomyces flavelus, Streptomyces griseolus, Streptomyces lividans, Streptomyces olivaceus, Streptomyces tanashiensis, Streptomyces virginiae, Streptomyces antibioticus, Streptomyces cacaoi, Streptomyces lavendulae, Streptomyces viridochromogenes, Aeromonas salmonicida, Bacillus pumilus, Bacillus circulans, Bacillus thiaminolyticus, Bacillus licheniformis, Bacillus subtilis, Bacillus amyloliquifaciens, Bacillus coagulans, Escherichia freundii, Microbacterium ammoniaphilum, Serratia marcescens, Salmonella typhimurium, Salmonella schottmulleri, Klebsiella oxytoca, Klebsiella pneumonia and Xanthomonas citri . The present invention is also useful in conferring the ability to use glycerol as the source of carbon in those yeast strains selected for the production of a commercially useful chemical, for example, but not limited to, a yeast selected from the following genera: Saccharomyces, Kluyveromyces, Candida, Zygosaccharomyces, Torulopsis, Torulospora, Williopsis, Issatchenkia, Pichia, Schizosaccharomyces, Phaffia, Cryptoccus, Yarrowia, Saccharomycopsis , etc.,
[0052] Glycerol used as a feedstock in the present invention can be derived from the biodiesel industry. It is preferable to remove the contaminants in the glycerol derived from biodiesel industry before its use in the fermentation process for the production of commercially useful chemicals. In a preferred embodiment, the glycerol is derived from a biodiesel industry where a heterogeneous catalyst is used leading to the production of glycerol with minimal contaminating components. Some of the contaminants such as ethanol and methanol can be removed through distillation. Dilution of the original glycerol stock solution is yet another approach to reduce the effect of contaminants.
[0053] The glycerol byproduct from biodiesel manufacturing is known to contain some minority contaminating compounds, such as water, methanol or ethanol, and salt ions, such as sodium, potassium, magnesium, calcium, ammonium, chloride, sulfate, and phosphate. If this “crude” glycerol is diluted about five-fold to ten-fold, then the contaminating compounds will be diluted to concentrations that should be tolerated by microorganism, including microorganisms of the instant invention. Nonetheless, it is preferable to at least partially remove the contaminating compounds prior to fermentation. Since the glycerol is a large volume byproduct, and might be derived from more than one biodiesel manufacturing facility, there might be some unpredictable variability between batches, so it is possible that levels of the contaminants in some batches or lots might be undesirable. In addition, the ionic contaminants might be less expensive to remove prior to fermentation compared to removal after fermentation. In the event that the desired product (for example an organic acid) is desired to be free of one or more of the contaminants, the contaminants must be removed either before or after fermentation. For example, if the organic acid produced is destined to be chemically modified (for example, hydrogenated) and/or polymerized into a plastic, then all forms of sulfur and phosphorus must be at least partially removed in order to protect catalysts from being poisoned. As another example, the methanol or ethanol might also act as chain terminators during polymerization, since they only have one reactive group.
[0054] Lower alcohols such as methanol and ethanol can be removed by distillation and/or reduced pressure. The ionic contaminants can be removed by ion exchange resins. Since the glycerol is uncharged at non-extreme pH's, the crude glycerol can be passed over a cation exchange resin that started in the hydrogen (H + ) form, followed by passage over an anion exchange resin that started in the hydroxide (OH − ) form, or vice versa. Alternatively, the crude glycerol can be passed over a mixed bed ion exchange resin that contains a mixture of the two types of resin. Using the two different resins in series is preferable to a mixed bed, since regeneration of the resins is then easier. The ion exchanges can be done with columns or batch wise. Glycerol should not be bound by either type of resin, while the ions should be retained by the resins.
[0055] Ions can also be removed from crude glycerol by other well known methods, such as electrodialysis, or by filtration through membranes, either charged or uncharged, that can discriminate between glycerol and the undesirable contaminants. Glycerol can also be purified by distillation or vacuum distillation.
[0056] The microbial organisms suitable for the production of commercially useful chemicals can be obtained a number of different ways. According to a preferred embodiment, a microbial cell obtained through a combined process of genetic engineering and metabolic evolution for the production of a particular commercially useful chemical using a carbon source other than glycerol such as glucose is used as a parental strain. For example, the KJ122 strain of E. coli described in detail (Jantama et al., 2008a; Jantama et al., 2008b; Zhang et al., 2009a; Zhang et al., 2009b) can be used as a parental strain to obtain a strain capable of using glycerol as a source of carbon in the commercial production of succinic acid. In the first stage of generating a strain useful in the production of succinic acid using glycerol as the source of carbon, the KJ122 strain is subjected to specific genetic manipulations to enhance the uptake and metabolism of glycerol. The genetic manipulations of the glycerol metabolic pathway can be followed by a process of metabolic evolution to obtain a bacterial strain with a commercially attractive yield, titer, and productivity for the production of succinic acid using glycerol as the source of carbon.
[0057] Based on our current understanding of the glycerol metabolic pathway inside a microbial cell, one can identify appropriate targets for genetic manipulation within the glycerol metabolic pathway. FIG. 1 provides an overview of our current understating about the glycerol metabolic pathway within a microbial cell.
[0058] Entry of glycerol from the culture medium into the microbial cell is mediated by a facilitated diffusion protein encoded by glpF gene. Once inside the cell, glycerol is metabolized by two different routes leading to the formation of dihydroxyacetone phosphate. In one pathway considered to be active under anaerobic conditions, glycerol is acted upon by glycerol dehydrogenase encoded by gldA gene. The oxidation of glycerol by glycerol dehydrogenase yields dihydroxyacetone accompanied by the formation of NADH. In the next stage, dihydroxyacetone is phosphorylated by phosphoenolpyruvate-dependent or an ATP-dependent dihydroxyacetone kinase encoded by dhaKLM. This phosphorylation reaction leads to the formation of dihydroxyacetone phosphate. This pathway for glycerol metabolism is referred to as the non-classical pathway for glycerol metabolism.
[0059] In another route for glycerol metabolism within the microbial cell considered to be operative under aerobic conditions, or anaerobic conditions where an alternative electron acceptor is present, such as nitrate or fumarate, glycerol is phosphorylated to produce glycerol-3-phosphate. In the next step, the glycerol-3-phosphate is oxidized by glycerol-3-phosphate dehydrogenase encoded by GlpD or GlpABC leading to the formation of dihydroxyacetone phosphate. This pathway for glycerol metabolism is referred to the as classical pathway for glycerol metabolism.
[0060] Dihydroxyacetone resulting from both the classical and non-classical pathway for glycerol metabolism is acted upon by triosephosphate isomerase leading to the formation of glyceraldehyde-3-phosphate. The glyceraldehyde-3-phosphate thus formed can pass through the rest of the glycolytic pathway and ultimately enter into the tricarboxylic acid cycle leading to the accumulation of one or other metabolic intermediate based on the nature of the genetic alterations that have occurred in the glycolytic, fermentative and tricarboxylic acid cycle pathways.
[0061] Beside the difference in the nature of the enzymes and the cofactors involved, the classical and non-classical pathways for glycerol metabolism differ from each other in the nature of regulations controlling the operation of these two glycerol metabolic pathways.
[0062] The classical glycerol pathway is regulated in two different ways. First, expression of glpF, glpK, glpD, and glpABC are all repressed by a protein encoded by glpR in the presence of the intermediate, G3P. Second, the GlpK enzyme is inhibited by fructose 1,6 bisphosphate, and by the non-phosphorylated form of the phosphotransferase system (PTS) component, Enzyme IIA Glc (also called EIIA Glc and formerly called Enzyme III Glc or EIII Glc ), which, in the case of E. coli , is encoded by the crr gene. A consequence of these regulatory mechanisms is that utilization of glycerol is strongly inhibited when glucose is present in the medium. When cells are grown in the presence of glucose, the concentration of both inhibitors of GlpK increases. For the purposes of this patent application, the inhibition of GlpK activity by either fructose 1,6 bisphosphate or EIIA Glc is referred to as feedback inhibition or a negative regulatory mechanism. The term “deregulated glycerol pathway” is defined as a pathway for glycerol utilization in which one or more negative regulatory mechanisms that operate on a glycerol utilization pathway have been decreased in function or entirely removed by genetic changes in the host organism. Such genetic changes include, but are not limited to, 1) a decrease or elimination on function of a repressor such as GlpR, 2) an alleviation of some, or all, inhibition of a glycerol kinase such as GlpK by a metabolic intermediate such as fructose-1,6-bisphosphate or by a protein such as a non-phosphorylated form of a phosphotransferase system (PTS) component, such as Enzyme IIA Glc , 3) a decrease in glucose inhibition of glycerol utilization, for example by decreasing a cells ability to import or metabolize glucose and/or 4) replacement of a native promoter of a glycerol utilization gene or operon, such as glpD, glpFKX and/or glpABC with a stronger or more constitutive promoter which is not subject to the repression by GlpR protein encoded by the glpR gene. A number of constitutively active promoters are well known in the art and any one of them can be used in the instant invention to replace the native promoter of glpFKX, glpD, and glpABC genes/operons, which are under the control of GlpR protein in a wild type bacterial cell. The replacement of a native promoter of any gene with a constitutively active promoter can be accomplished using one or other genetic engineering techniques well known in the art of microbial genetic engineering, such as the two-step allele replacement method described in Example 6, in which the native promoter is replaced by insertion of a cat, sacB cassette, which is subsequently replaced by a constitutively active promoter sequence well known in the art.
[0063] There are several reports of mutant alleles of glpK that are resistant to feedback inhibition by G3P, or non-phosphorylated Enzyme IIA Glc , or both (Bell, 1974; Pettigrew et al., 1996). Some of these alleles were originally isolated by Cronan and Bell (Cronan and Bell, 1974a; Cronan and Bell, 1974b) in strains named BB20-14 and BB26-36, which were obtained from G3P auxotrophs by selection for growth on glucose plus glycerol. These strains were presumed to contain feedback resistant glycerol kinases. The DNA sequence of the glpK genes from those strains has not heretofore been published. The Coli Genetic Stock Center (CGSC) at Yale University, New Haven, Conn., USA can provide these two strains, and the curators have named the alleles in these two strains glpK15(fbR) and glpK14(fbR), respectively. For simplicity, in this specification, we shall call these alleles glpK i 15 and glpK i 14, respectively, where the “i” superscript denotes insensitive to feedback inhibition.
[0064] Another feedback resistant allele of glpK, named glpK i 22, was first isolated by Zwaig and Lin in a strain named Lin 43 (Zwaig and Lin, 1966), and was later characterized and sequenced by Pettigrew et al. (1996). The mutant was identified by its ability to incorporate radioactive glycerol in the presence of glucose.
[0065] Another approach that has been followed in isolating feedback resistant alleles of glpK was to select for suppression of certain PTS mutations (Berman and Lin, 1971). This approach gave rise to strain Lin 225, which contained a glycerol kinase that was resistant to inhibition by fructose 1,6-bisphosphate, but the glpK gene from that strain was never characterized. The glpK allele in strain Lin 225 was named glpK i 31 by the Coli Genetic Stock Center at Yale University.
[0066] Whole genome-sequencing of E. coli to monitor the acquisition and fixation of mutations that conveyed a selective growth advantage during adaptation to glycerol-based growth medium has identified a series of mutations in the gene for glycerol kinase (Iberra et al., 2002; Herring et al., 2006; Honisch et al., 2004). Partially purified protein from cells expressing the mutant glpK gene showed reaction rates for glycerol kinase enzyme 51%-133% higher than wild-type, and some of those mutants showed reduced inhibition of glycerol kinase by fructose-1,6-bisphosphate (Herring et al., 2006).
[0067] For purposes of this invention, a feedback resistant glycerol kinase is defined as a glycerol kinase that has higher specific activity than the related wild type enzyme in the presence of fructose 1,6-bisphosphate, or in the presence of the non-phosphorylated form of the phosphotransferase system (PTS) component, Enzyme IIA Glc from the same organism, or in the presence of both inhibitors. The feedback resistant property can be referred to in discussing the glycerol kinase enzyme, the gene encoding the glycerol kinase, or an allele of glycerol kinase.
[0068] Thus, four methods for isolating feedback resistant glpK alleles are known in the art: (1) Selection for growth of G3P auxotrophs on glucose plus glycerol, (2) Uptake of radioactive glycerol in the presence of glucose, (3) Suppression of a PTS Enzyme I mutant, and (4) Selection for more rapid growth in minimal glycerol medium (Bell, 1974; Zwaig and Lin, 1966; Berman and Lin, 1971; Honisch et al., 2006). Any one of those four methods can be made use of in the present invention in isolating a feedback resistant glpK allele. Although the examples provided in the present invention are based on E. coli , similar approach can be followed in any bacterial species and in particular in any other bacterial species of the genera Klebsiella, Salmonella, Enterobacter, Serratia , and Citrobacter.
[0069] Any one of these feedback resistant alleles of glpK can be used to replace the wild type glpK gene in a bacterial strain already developed for the production of a particular commercially important chemical. The wild type glpK gene in the KJ122 strain of E. coli already developed for the commercial production of succinic acid can be replaced with a mutant glpK allele which is resistant to feedback inhibition. Alternatively, the replacement of wild type glpK gene with a mutant allele of glpK can be accomplished in a wild type E. coli and the resulting bacterial strain with the mutant allele of glpK can be used as the parental strain in developing a strain for the commercial production of succinic acid.
[0070] The replacement of the wild type allele of glpK with a mutant allele of glpK can be accomplished by using one or other genetic engineering techniques well known in the art of microbial genetic engineering. In general, the wild type glpK gene in the parental strain is initially replaced by inserting an antibiotic marker gene at that locus. In the second stage, the antibiotic marker gene is replaced by a mutant allele of glpK. The mutant allele of glpK can be transferred from the strain reported to have a mutant allele of glpK to the recipient strain using a bacteriophage mediated transduction process. Alternatively, polymerase chain reaction can be used to clone the mutant allele from a recipient strain into a plasmid vector or directly into a chromosome. Subsequently, the plasmid vector with the mutant glpK allele can be used to transform the recipient bacterial strain. In another aspect of the present invention, when the nature of the mutation in the glpK gene is known at the nucleotide level, in vitro mutagenesis with synthetic oligonucleotides can be used to generate a mutant glpK allele in a plasmid vector. The mutant glpK allele from the plasmid vector can be used to replace the wild type glpK allele through transformation followed by double recombination. Alternatively, the mutant glpK allele contained on a linear DNA fragment can be used to replace the wild type glpK allele through transformation followed by double recombination.
[0071] In another embodiment of the present invention, deregulation of the glycerol pathway is conferred by means of overcoming the repression of expression of glpF, glpK, and glpABC genes by the repressor protein GlpR encoded by glpR gene. The repressive effect of GlpR protein can be overcome by two different ways. In the first method, the glpR gene sequence is altered so that the GlpR protein is no longer effective in repressing the expression of glpF, glpK, and glpABC genes. In the preferred embodiment, the synthesis of GlpR protein itself is inhibited. The inhibition of GlpR protein synthesis can be achieved by means of insertional inactivation of the glpR gene sequence. For example, an antibiotic marker cartridge can be inserted in the glpR open reading from so that the GlpR protein is no longer produced. In the most preferred embodiment, the glpR open reading frame is precisely removed and there is no foreign nucleotide sequence remaining at this locus.
[0072] In order to make sure that the glycerol utilization pathway within the microbial cell is fully deregulated, it is preferable to have feedback resistant glpK allele in addition to completely eliminating a functional glpR gene. These two genetic modifications can be carried out in a wild type bacterial strain to produce a parental bacterial strain with a completely deregulated glycerol utilization pathway. Subsequently the parental bacterial strain with a completely deregulated glycerol utilization pathway can further be subjected to specific genetic modifications and metabolic evolution to obtain a bacterial strain with high yield and productivity for the production of a particular metabolic product such as succinic acid or lactic acid. In the preferred embodiment, the inactivation of glpR gene and the introduction of feedback resistant allele of glpK are carried out in a strain that has already been genetically engineered and metabolically evolved for the production a particular commercially useful chemical. For example, the inactivation of glpR gene and the introduction of feedback resistant allele of glpK gene can be carried out in the KJ122 strain of E. coli already developed for the production of succinic acid using glucose as the source of carbon.
[0073] In another embodiment, the GlpR mediated repression of glpF, glpK, and glpABC gene expression is overcome by replacing the native promoter regions of glpF, glpK, and glpABC genes which is susceptible to regulation by GlpR repressor protein with a constitutive promoter not susceptible to repression by GlpR protein. In a preferred embodiment, in the bacterial strain with a constitutive promoter not susceptible to repression by GlpR, the wild type allele for glpK gene is replaced with a feedback resistant glpK allele. These two genetic modifications leading to the deregulation of glycerol utilization pathway can be carried out in a wild type bacterial strain leading to the formation of a parental strain with deregulated glycerol utilization pathway. Such a parental strain with a deregulated glycerol utilization pathway can further be subjected to genetic manipulations and metabolic evolution to produce a bacterial strain capable of producing a commercially useful chemical using glycerol as the source of carbon. Alternatively, replacement of the native promoters for glpF, glpK and glpABC genes with a well-defined constitutively active promoter and replacement of the wild-type allele for glpK with a feedback resistant glpK allele can carried out in a bacterial strain which is already developed for the commercial production of a specific chemical.
[0074] The microorganisms of the present invention are grown in a fermentation medium with microaeration. The preferred supply rate for oxygen (in the form of air at 40 ml/min in a 3 L starting volume) in the instant invention is about 0.0026/min, based on the starting volume of medium in the fermentor, which is equivalent to about 228 mg/liter-hour of oxygen. This rate is substantially lower than the optimal rate suggested by the prior art of Trinh and Srienc (2009), which was stated to be 0.15/min, and substantially higher than the optimal rate suggested by the prior art of Gonzalez and Campbell (WO/2010/051324), which was reported to be between 1 and 20 mg/liter-hour.
[0075] The term “genetically engineered” or “genetic engineering” as used herein refers to the practice of altering the expression of one or more enzymes in the microorganisms through manipulating the genomic DNA or a plasmid of the microorganism. The genomic manipulations involve either altering, adding or removing specific DNA sequences from the genomic DNA. The genetic manipulations also involve the insertion of a foreign DNA sequence into the genomic DNA sequence of the microorganism. In the most preferred embodiments of the present invention, some of the genetic manipulations are accomplished by means of removing specific DNA sequences from the genomic DNA of the microorganisms without introducing any foreign DNA. Certain genetic manipulations necessary to inactivate the expression of a gene coding for a particular protein product requires an insertion of a foreign DNA sequence into the genome of the microorganism. In the most preferred embodiment of the present invention, the introduced exogenous DNA sequences are ultimately removed from the genomic DNA of the microorganism so that the microorganism at the end of the genetic engineering process would have no exogenous DNA in its original genomic DNA. Various techniques necessary for accomplishing the objectives of the preferred embodiment of the present invention including the process for metabolic evolution have been described in detail in Jantama et al (2008a, 2008b). U.S. Pat. No. 7,629,162 and U.S. Patent Application Publication No. US 2009/0148914 and the International Patent Applications published under the Patent Cooperation Treaty with International Publication Numbers WO 2008/115958 and WO 2010/115067 also describe the genetic engineering techniques useful in practicing various embodiments of this present invention. These scientific publications as well as the patent documents cited are herein incorporated by reference for the purpose of providing the details for genetic engineering techniques useful for the present invention.
Example 1
Removal of Negative Regulation of Glycerol Uptake and Utilization in Strain KJ122
[0076] Three different minimal media can be used for plate selections of bacterial strains, for succinate production in test tubes, or for succinate production in pH controlled fermentors. The minimal media are listed in Table 1. Rich broth or plates were Luria Broth, also known as “LB” (10 g/l tryptone, 5 g/l yeast extract, 5 g/l sodium chloride). The following strains were obtained from the Coli Genetic Stock Center (CGSC), Yale University, New Haven, Conn.: JW 3386-1 (ΔglpR::kan) and JW 3897-1 (ΔglpK::kan). Using generalized phage transduction with P1vir, the ΔglpK::kan allele from JW 3897-1 was installed in KJ122, selecting for kanamycin resistance using 50 mg/l kanamycin sulfate in LB plus 25 mM sodium citrate, and confirming correct installation of ΔglpK::kan by lack of growth on minimal plates with glycerol as the sole carbon source ( FIG. 2 ). The resulting strain was named RY812. In parallel, the wild type lambda prophage residing in strain BB20-14 (obtained from John Cronan, University of Illinois, Champagne-Urbana, Ill.) was cured by P1vir transduction from strain TAP106 (also known as ATCC 47075) as the donor, which contains a defective lambda prophage that includes N::kan for selection, to give strain RY808, by selection for resistance to kanamycin as described above. In a second step, the glpK region from RY808, which contains the glpK i 15 allele, was transduced into RY812, selecting for growth on minimal SS glycerol plates (see Table 1), and confirming for loss of kanamycin resistance, to give strain RY829C. In a third step, the ΔglpR::kan allele of JW 3386-1 was transduced into RY829C, selecting for kanamycin resistance as described above, to give strain RY819J, which was an isolate that was shown to retain the nearby pck* allele (Zhang et al 2009a; Zhang et al., 2009b).
Example 2
Production of Succinate from Glycerol in Test Tubes
[0077] Strains KJ122 and RY819J were grown overnight aerobically in Luria Broth and then inoculated to give 0.05 OD 600 in 12.5 ml of NBS medium containing 20 g/l glycerol in 15 ml polypropylene test tubes with screw caps. The tubes were capped tightly and rolled on a New Brunswick Scientific roller drum at 37° C. at about 60 rpm for 48 hours. Culture samples were prepared by removing cells by centrifugation through Costar spin filters, diluted as necessary in 0.008M sulfuric acid, and analyzed by high pressure liquid chromatography (HPLC) using an Agilent Model 1200 apparatus installed with a BioRad Aminex HPX-87H column. The column was run at 50° C., with 0.008 M sulfuric acid as the solvent, and the detection was by both refractive index and absorption at 210 nm. Samples were analyzed for concentration of succinic acid, glycerol, glucose, acetate, and other byproducts. Concentrations of each chemical were calculated using standard curves derived from pure commercial compounds. KJ122 produced 0.06 g/l succinate, while RY819J produced 0.61 g/l succinate, a clear improvement over the starting strain.
Example 3
Metabolic Evolution of RY819J
[0078] Strain RY819J was grown overnight aerobically in NBS medium containing 10 g/l glucose and 10 g/l glycerol, and then inoculated into a 500 ml working volume covered fermentor containing 300 ml of AM1 medium (see Table 1) containing 50 g/l glycerol and 50 g/l glucose, to give a starting OD 600 of 0.2. The fermentor was stirred with a magnetic stirrer at 150 rpm, but no deliberate aeration was supplied. As such, the fermentor was not strictly anaerobic, since some air is admitted during sampling and from base addition. The pH was controlled at 6.5 by addition of 3M potassium carbonate, and the temperature was maintained at 40° C. Succinate was produced for about 48 hours, and glycerol and glucose were consumed in parallel, but after 48 hours, a portion of the glycerol remained. The final cell density was about 3.0 OD 600 . A sample from the first fermentor was used to inoculate a second fermentor to a starting OD 600 of 0.2, using the same medium, and growth and succinate production resumed. This re-inoculation procedure shall be called a “transfer” in this specification. After succinate production ceased, a second transfer of inoculum to a third fermentor was done as above, followed by several more transfers. During the first few transfers, glucose was present in the medium to stimulate growth. In general, growth was slow in the first several transfers unless some glucose or potassium nitrate was present, so to obtain sufficient growth for subsequent transfers, some glucose or nitrate was added to the fermentors at various times to boost growth. The first four transfers started with 50 g/l glucose plus 50 g/l glycerol. Transfers 5 to 9 started with only 50 g/l glycerol and no glucose, but in order to obtain sufficient growth for the next transfer, 10 g/l glucose was added during the fermentation. Transfer 10 was supplemented first with 1 g/l potassium nitrate, and later with 10 g/l glucose. A summary of the additives and the times of the additions to the fermentors is given in Table 2. Starting with the 11 th transfer, no glucose or nitrate was added to the medium; the sole carbon source was 50 g/l glycerol. Nonetheless, the growth eventually was sufficient to make a transfer. Samples were analyzed at various times by HPLC as described above. At transfer 11, after 384 hours, all of the glycerol had been consumed and the succinate titer was 425 mM, which was calculated after dilution with base to give a yield of 1.08 grams succinate per gram of glycerol consumed. Three more transfers were performed, but no further significant improvement in the performance of the strain in terms of succinic acid production was found. A single colony was isolated from the 14 th transfer, and the isolate was named RY819J-T14 ( FIG. 2 ).
Example 4
DNA Sequencing of Various glpK Allele
[0079] The wild type DNA sequences of the glpFKX operons of E. coli C (ATCC 8739) and E. coli K-12, from which many of the strains used herein were derived, can be found in the GenBank database at the National Institutes of Health, USA, accession numbers NC — 010468 and NC — 000913, respectively.
[0080] The glpK gene, surrounded by about half of the glpF gene and half of the glpX gene, was amplified by polymerase chain reaction (PCR) using genomic DNA from the following E. coli strains: BB20-14, BB26-36, Lin 225 and Lin 298. The latter three strains were all obtained from the Coli Genetic Stock Center (CGSC), Yale University, New Haven, Conn. According to the CGSC, these four strains namely BB20-14, BB26-30, Lin 225 and Lin 298 contain, among other mutations, glpK i 15, glpK i 14, glpK i 31, and glpK i 22, respectively. Of these, only glpK i 22 had been sequenced, revealing a G304S amino acid change (Pettigrew et al, 1996; Honisch et al, 2004). However, this sequence was derived from strain Lin 43, which was not available from CGSC. Therefore the instant inventors used Lin 298, which was available and is reported to be derived from Lin 43. The PCR primers used for the amplification were BY19 (SEQ ID no. 1) and BY44 (SEQ ID No. 2). DNA sequences of PCR and sequencing primers are given in Table 3. The reagents for PCR were the Phusion Master Mix from New England BioLabs, which was used as recommended by the supplier. The resulting blunt-ended DNA fragments from BB20-14, BB26-30, Lin 225 and Lin 298 were gel purified and cloned into the Eco RV site of pRY521 (SEQ ID No. 10), to give plasmids pMH4-20, pMH4-26, pMH4-225, and pMH4-298, respectively.
[0081] The glpK gene and flanking sequences from each of these plasmids was sequenced by the Sanger chain termination method using sequencing primers BY15 (SEQ ID No. 3), BY16 (SEQ ID No. 4), BY19 (SEQ ID No. 1), BY30 (SEQ ID No. 6), and BY44 (SEQ ID No. 2). Three of the four plasmids contained mutations in the glpK coding region. All DNA sequence coordinates given in this specification count the first base of the open reading frame as 1 and all amino acid coordinates count the start codon as 1. For the three letter amino acid codes, see the 2007-2008 New England BioLabs Catalog, p. 361. pMH4-20 had two point mutations in glpK (G163A; Ala55Thr and G470A; Arg157His) and, unexpectedly, a single point mutation in glpF (C821T; Pro274Leu).
[0082] pMH4-26 had a single point mutation in glpK (C164T; Ala55Val) and, unexpectedly, a single point mutation in glpF (G724A; Val242Ile). pMH4-225 had a single point mutation in glpK (C176A; Ser59Tyr) but no mutation in glpF. pMH4-298 had no mutation in the region sequenced. This latter result contradicts the published literature, which implies that strain Lin 298 should have the same glpK mutation as Lin 43 (see above). It appears that the isolate of Lin 298 that we used had somehow lost the glpK i 22 allele, or that our isolate was not in fact strain Lin 298, or that Lin 298 was not in fact derived from Lin 43.
[0083] The most likely interpretation of the above results is that the point missense mutations in the glpK genes accounts for the demonstrated or inferred feedback resistance of the encoded GlpK enzymes. Since the glpK i 15 allele contained two separated mutations, it is possible that either mutation by itself could confer a feedback resistant phenotype, but in any case, the inventors could conclude that the combination of the two mutations was sufficient for the feedback resistant phenotype of glycerol kinase in BB20-14.
[0084] In addition to the above plasmids, two similar plasmids were constructed from the glpK regions of KJ122 and RY819J, to give pMH4-KJ and pMH4-RY819 respectively. The DNA sequences of the cloned inserts were as expected. pMH4-KJ contained wild type glpK and glpF sequences, while pMH4-RY819 contained a sequence that was identical to that of pMH4-20, including the two point mutations in glpK and the single point mutation in glpF.
Example 5
Removal of the Kanamycin Resistance Gene from RY819J-T14
[0085] Strain RY819J-T14 contains the ΔglpR::kan allele transduced from strain JW 3386-1, which is a member of the “Keio Collection” (Baba et al., 2006). As such, the kanamycin resistance gene, kan, can be removed to leave a short DNA “scar” by passing a helper plasmid, pCP20, through the strain (Datsenko and Wanner, 2000). This process was performed on RY819J-T14 to give the kanamycin sensitive derivative, strain MH23.
Example 6
Correction of the Mutation Found in the glpF Gene of RY819J and Descendents
[0086] A point mutation was found in the glpF gene of strain BB20-14, and because this mutation is closely linked to the glpK gene, it became installed in RY819J and passed down to strain MH23 (see Examples 1 and 5). The mutation in glpF was cured by replacing the region with a wild type DNA sequence, using the two step gene replacement method similar to that described by Jantama et al (2008a, 2008b). In the first step, a cat, sacB cassette was amplified by PCR using pCA2 (SEQ ID No. 11) as a template and primers BY71 (SEQ ID No. 6) and BY72 (SEQ ID No. 7). The resulting 3.2 kilobase DNA fragment was transformed into strain MH23 containing the helper plasmid pKD46 (Datsenko and Wanner, 2000), selecting for chloramphenicol resistance on LB plus 30 mg/l chloramphenicol, to give strain MH27 (glpF:: cat, sacB). For the second step, the wild type glpF region was amplified by PCR using E. coli C (ATCC 8739) DNA as template and primers BY73 (SEQ ID No. 8) and BY74 (SEQ ID No. 9). The resulting 1.7 kilobase DNA fragment was transformed into MH27, selecting for sucrose resistance on LB plus 6% sucrose, and confirming for chloramphenicol sensitivity on LB plus 30 mg/l chloramphenicol. The resulting strain, after curing of pKD46, was named MH28 ( FIG. 3 ). The glpF and glpK region of MH28 was sequenced to confirm that the wild type glpF had been installed and that the feedback resistant mutations in glpK had been retained through the steps of strain construction.
Example 7
Production of Succinate from Glycerol by KJ122 and MH28 in pH Controlled Fermentors
[0087] Starting strain KJ122 and derivative strain MH28 were assessed for succinate production in 7 liter New Brunswick Scientific fermentors with a starting volume of 3.15 liters, including the inocula ( FIGS. 5 and 6 ). The 150 ml inocula were grown aerobically in shake flasks overnight using NBS medium (see Table 1) containing 20 g/l glycerol and 0.1 M MOPS buffer, pH 7.0. The inocula were added to fermentors containing 3 liters of fermentation medium that nominally included 120 g/l glycerol (A.C.S. grade, Mallinckrodt Chemicals, catalog number 5092-02, CAS No. 56-81-5) as the sole carbon source (see Table 1). See Table 4 for the measured concentration of glycerol at time zero and the end of fermentation. The temperature was kept at 39° C., and the pH was kept at 7.0 by pumping in 3M potassium carbonate, as required. Microaeration was constant by pumping in air at 40 ml/min, which was shown to be sufficient for an attractive level of succinate production, by systematically varying the aeration rate. The impeller speed was 750 rpm.
[0088] Samples were taken and assayed for organic acids and glycerol using HPLC as described above. By 48 hours, the glycerol had been completely consumed by strain MH28, but not by parent strain KJ122 (see Table 4). MH28 produced 84.3 g/l succinate, for a yield of 1.0 g/g glycerol consumed. The only significant byproduct was acetate at 3.3 g/l. In contrast, KJ122, the starting strain, made only 18.9 g/l succinate and left 83.5 g/l glycerol in the final broth at 48 hours, for a succinate yield of 0.6 g/g glycerol consumed. Clearly, strain MH28 is much improved over strain KJ122 for succinate production under the conditions tested.
[0089] A scientist skilled in the art would be able use the methods described herein to construct strains similar to MH28, but containing other alleles of the glpK gene that encode feedback resistant glycerol kinase. Several possible alleles were mentioned above, including the glpK i 14, glpK i 22, and glpK i 31 alleles, as well as alleles described by Honisch et al. (2004). For example mutations causing the following amino acid changes in glycerol kinase: Gln28Pro, Trp54Gly, Val62Leu, Asp73Ala, Asp73Val, Gly231Asp, and the insertion of 235GlyGlyLys can be used to confer feedback resistant phenotype.
[0090] A scientist skilled in the art would also recognize that the methods disclosed herein could be used to construct strains that ferment glycerol to other organic acids of commercial interest, such as lactate, malate, and fumarate.
[0091] Although the specific examples given in this specification used E. coli as a production organism, and the genes used in the examples use the E. coli nomenclature (for example glpR (glycerol-3-phosphate dependent repressor), glpK (glycerol kinase), glpABC (glycerol-3-phosphate dehydrogenase), and glpF (glycerol facilitated diffuser)), one skilled in the art will know that genes and proteins that are functional analogs and structural homologs of these components from other microorganisms can be engineered as taught in this specification to achieve enhanced utilization of glycerol for production of chemicals of commercial interest by fermentation in other microorganisms.
REFERENCES
[0092] All references are listed herein for the convenience of the reader. Each is incorporated by its entirety.
U.S. Pat. No. 5,000,000 U.S. Pat. No. 5,028,539 U.S. Pat. No. 5,424,202 U.S. Pat. No. 5,482,846 U.S. Pat. No. 5,916,787 U.S. Pat. No. 6,849,439 U.S. Pat. No. 7,098,009 U.S. Pat. No. 7,223,567 U.S. Pat. No. 7,241,594 U.S. Pat. No. 7,244,610 U.S. Pat. No. 7,262,046 U.S. Pat. No. 7,470,530 U.S. Pat. No. 7,629,162 U.S. Pat. No. 7,790,416 United States Patent Application Publication No. US 2009/0176285 United States Patent Application Publication No. US 2009/0186392 United States Patent Application Publication No. US 2009/0148914 United States Patent Application Publication No. US 2010/0184171 United States Patent Application Publication No. US 2011/0008851 International Patent Application Publication No. WO/2007/115228 International Patent Application Publication No. WO 2008/115958 International Patent Application Publication No. WO 2009/024294 International Patent Application Publication No. WO 2009/048202 International Patent Application Publication No. WO 2010/051324 International Patent Application Publication No. WO 2010/092155 International Patent Application Publication No. WO 2010/115067 Baba, T., Ara, T., Hasegawa, M., Takai, Y., Okumura, Y., Baba, M., Datsenko, K. A., Tomita, M., Wanner, B. L., and Mori, H. (2006) Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection. Mol Syst Biol 2: 2006 0008. Bell, R. M. (1974) Mutants of Escherichia coli defective in membrane phospholipid synthesis: macromolecular synthesis in an sn-glycerol 3-phosphate acyltransferase Km mutant. J Bacteriol 117: 1065-1076. Berman, M., and Lin, E. C. (1971) Glycerol-specific revertants of a phosphoenolpyruvate phosphotransferase mutant: suppression by the desensitization of glycerol kinase to feedback inhibition, J Bacteriol 105: 113-120. Blankschien, M. D., Clomburg, J. M., and Gonzalez, R. (2010) Metabolic engineering of Escherichia coli for the production of succinate from glycerol. Metab Eng 12: 409-419. Chen, Z., Liu, H., Zhang, J., and Liu, D. (2010) Elementary mode analysis for the rational design of efficient succinate conversion from glycerol by Escherichia coli. J Biomed Biotechnol 2010: 518743. Clomburg, J. M., and Gonzalez, R. (2010) Biofuel production in Escherichia coli : the role of metabolic engineering and synthetic biology. Appl Microbiol Biotechnol 86: 419-434. Clomburg, J. M., Gonjalez, R. (2010) Metabolic Engineering of Escherichia coli for the production of 1,2-propanediol from glycerol. Biotech. Bioeng.: 108: 867-879. Cronan, J. E., Jr., and Bell, R. M. (1974a) Mutants of Escherichia coli defective in membrane phospholipid synthesis: mapping of the structural gene for L-glycerol 3-phosphate dehydrogenase. J Bacteriol 118: 598-605. Cronan, J. E., Jr., and Bell, R. M. (1974b) Mutants of Escherichia coli defective in membrane phospholipid synthesis: mapping of sn-glycerol 3-phosphate acyltransferase Km mutants. J Bacteriol 120:227-233. Datsenko, K. A., and Wanner, B. L. (2000) One-step inactivation of chromosomal genes in Escherichia coli K-12 using PCR products. Proc Natl Acad Sci USA 97: 6640-6645. De Guzman, D. (2010) ICIS Chemical Business, Volume 18, p. 48 Durnin, G., Clomburg, J., Yeates, Z., Alvarez, P. J., Zygourakis, K., Campbell, P., and Gonzalez, R. (2009) Understanding and harnessing the microaerobic metabolism of glycerol in Escherichia coli. Biotechnol Bioeng 103: 148-161. Gonzalez, R., Murarka, A., Dharmadi, Y., and Yazdani, S. S. (2008) A new model for the anaerobic fermentation of glycerol in enteric bacteria: trunk and auxiliary pathways in Escherichia coli. Metab Eng 10: 234-245. Herring, C. D., Raghunathan, A., Honisch, C., Patel, T., Applebee, M. K., Joyce, A. R., Albert, T. J., Blattner, F. R., van den Boom, D., Cantor, C. R., and Palsson, B. O. (2006) Comparative genome sequencing of Escherichia coli allows observation of bacterial evolution on a laboratory timescale. Nat Genet. 38: 1406-1412. Honisch, C., Raghunathan, A., Cantor, C. R., Palsson, B. O., and van den Boom, D. (2004) High-throughput mutation detection underlying adaptive evolution of Escherichia coli -K12 . Genome Res 14: 2495-2502. Jantama, K., Haupt, M. J., Svoronos, S. A., Zhang, X., Moore, J. C., Shanmugam, K. T., and Ingram, L. O. (2008) Combining metabolic engineering and metabolic evolution to develop nonrecombinant strains of Escherichia coli C that produce succinate and malate. Biotechnol Bioeng 99: 1140-1153. Jantama, K., Zhang, X., Moore, J. C., Shanmugam, K. T., Svoronos, S. A., and Ingram, L. O. (2008) Eliminating side products and increasing succinate yields in engineered strains of Escherichia coli C. Biotechnol Bioeng 101: 881-893. Ibarra, R. U., Edwards, J. S., and Palsson, B. O. (2002) Escherichia coli K-12 undergoes adaptive evolution to achieve in silico predicted optimal growth. Nature 420: 186-189. Lin, E. C. (1996), in Escherichia coli and Salmonella: cellular and molecular biology, 2nd ed., ASM Press, Washington, D.C., pp 325-326. Ondrey, G. (2004) Chemical Engineering, October, 2004, p. 13). Palsson, B. O. (2011) Adaptive Laboratory Evolution, Microbe 6, 69-74. Pettigrew, D. W., Liu, W. Z., Holmes, C., Meadow, N. D., and Roseman, S. (1996) A single amino acid change in Escherichia coli glycerol kinase abolishes glucose control of glycerol utilization in vivo. J Bacteriol 178. 2846-2852. Trinh, C. T., and Srienc, F. (2009) Metabolic engineering of Escherichia coli for efficient conversion of glycerol to ethanol. Appl Environ Microbiol 75. 6696-6705. Yazdani, S. S., and Gonzalez, R. (2007) Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry. Curr Opin Biotechnol 18: 213-219. Yazdani, S., and Gonzalez, R. (2008) Engineering Escherichia coli for the efficient conversion of glycerol to ethanol and co-products. Metabolic Engineering 10: 340-351. Zhang, X., Jantama, K., Moore, J. C., Jarboe, L. R., Shanmugam, K. T., and Ingram, L. O. (2009) Metabolic evolution of energy-conserving pathways for succinate production in Escherichia coli. Proc Natl Acad Sci USA 106: 20180-20185. Zhang, X., Jantama, K., Shanmugam, K. T., and Ingram, L. O. (2009) Reengineering Escherichia coli for Succinate Production in Mineral Salts Medium. Appl Environ Microbiol 75: 7807-7813. Zhang, X., Shanmugam, K. T., and Ingram, L. O. (2010) Fermentation of glycerol to succinate by metabolically engineered strains of Escherichia coli. Appl Environ Microbiol 76:2397-2401. Zwaig, N., and Lin, E. C. (1966) Feedback inhibition of glycerol kinase, a catabolic enzyme in Escherichia coli. Science 153: 755-757. Zwaig, N., Kistler, W. S., and Lin, E. C. (1970) Glycerol kinase, the pacemaker for the dissimilation of glycerol in Escherichia coli. J Bacteriol 102: 753-759.
[0000]
TABLE 1
Chemical composition of minimal media used in the present invention. The
final pH was adjusted to 7.0 with ammonia or phosphoric acid as needed
New Brunswick
1000 X
Spizizen
Scientific
Fermentation
Trace
Ingredient
Salts (SS)
(NBS)
AM1
medium
Elements
KH 2 PO 4
6.0
g/l
3.5
g/l
K 2 HPO 4
5.0
g/l
K 2 HPO 4 •3H 2 O
17.4
g/l
(NH 4 ) 2 HPO 4
3.5
g/l
2.63
g/l
2.63
g/l
(NH 4 )H 2 PO 4
0.87
g/l
0.87
g/l
MgSO 4
0.2
g/l
1
mM
1.5
mM
2.0
mM
CaCl 2
0.1
mM
0.1
mM
0.1
mM
(NH 4 ) 2 SO4
2
g/l
Na 3 Citrate
10
g/l
KHCO 3
0-100
mM
0-30
mM
KCl
2
mM
Betaine
1
mM
1.33
mM
Glucose
0 -100
g/l
0-100
g/l
Glycerol
10-100
g/l
20-100
g/l
100-120
g/l
1000 X trace elements
1
ml/l
1
ml/l
1
ml/l
3.3
ml/l
MOPS buffer
0.1M, pH 7.4
Antifoam 204
8
ppm
FeCl 3
1.6
g/l
CoCl 2 •6H 2 O
0.2
g/l
CuCl 2
0.1
g/l
ZnCl 2 •4H 2 O
0.2
g/l
NaMoO 4
0.2
g/l
H 3 BO 3
0.05
g/l
MnCl 2 •4H 2 O
0.55
g/l
HCl
0.1M
[0000]
TABLE 2
Metabolic evolution of PY819J. All transfers started with 50 g/l glycerol. Glucose
was added either at the start or at a later time period as indicated below.
Time period at
which the supple-
Amount of glucose
Amount of glucose
mental glucose was
Total duration
added at the start
added as a supple-
added (hours from
of the fermen-
Transfer
of fermentation
ment at a later
the start of the
Neutralizing
tation before
number
(g/l)
time period (g/l)
fermentation)
base*
next transfer
1
50
none
a
72
2
50
none
a
71
3
50
none
a
71
4
50
none
a
74
5
0
10 g/l glucose
49
b
145
6
0
10 g/l glucose
48
b
97
7
0
10 g/l glucose
72
b
96
8
0
10 g/l glucose
165
b
214
9
0
10 g/l glucose
239
b
288
10
0
1 g/l KNO 3
120
b
216
10 g/l glucose
142
11
0
none
b
98
11a
0
none
b
413
13
0
none
b
211
14
0
none
b
*Neutralizing bases were a: 1.2M KOH + 2.4M K 2 CO 3 ; b: 3M K 2 CO 3
[0000]
TABLE 3
Primer sequences and bacterial plasmids
Primers
Primer No./Primer name
Primer sequence
SEQ ID No. 1/BY19
5′ tccggcgcgccaccaatac 3′
SEQ ID No. 2/BY44
5′ cagtgtcatttggggactggggg 3′
SEQ ID No. 3/BY15
5′ gtatacggtcagactaacattggcggc 3′
SEQ ID No. 4/BY16
5′ cgccagtgttcatcagcataaagcag 3′
SEQ ID No. 5/BY30
5′ atcagctttcgccagcacttctaccagc 3′
SEQ ID No. 6/BY71
5′acttttgcttccagtttctcaaacacttctaatgacattgtcatacctctgtgacg
gaagatcacttcgcagaata 3′
SEQ ID No. 7/BY72
5′acgatatattttttttcagtcatgtttaattgtcccgtagtcatattacatgaagca
cttcactgacaccctcatc 3′
SEQ ID No. 8/BY73
5′caacctggttttgggtagatttgctc3′
SEQ ID No. 9/BY74
5′acagtaaagaaattacgcggaagatgaag3′
Bacterial Plasmids
SEQ ID No./Plasmid Name
Description
SEQ ID No. 10/pRY521
Parent of pMH4 series
SEQ ID No. 11/pCA2
Source of cat, sacB cassette
[0000]
TABLE 4
Production of succinate from glycerol by KJ122 and MH28
Succ-
Re-
OD at
Starting
inate
maining
Acetate
Succinate
550
Strain
glycerol
Time
titer
glycerol
titer
yield g/g
nm
KJ122
116 g/l
48 hr
19.8 g/l
83.5 g/l
0.6 g/l
0.6
7.6
MH28
111 g/l
48 hr
84.3 g/l
0 g/l
3.3 g/l
1.0
8.0
|
The present invention is in the field of producing organic acids and other useful chemicals via biological fermentation using glycerol as a source of carbon. Novel microorganisms and fermentation processes are described that are capable of converting glycerol to useful organic acids in high yield and high purity.
| 2
|
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to low friction swivel joints having zero backlash in tension and compression.
2. Prior Art
Several different types of hydrostatic and hydrodynamic bearings have been used in swivel joints. U.S. Pat. No. 3,392,995 shows a pressure balanced bearing which is used for reacting loads, but which utilizes a mechanical valve to provide pressure for functioning. Further, continuous hydraulic fluid flow is required in the joint. As disclosed, hydraulic oil must either flow into or out of the joint. Further, if the sealing surface of the reaction pad does not remain perpendicular to the load axis as the joint swivels side loads will be encountered, resulting in friction and requiring higher torques to overcome such frictional loads. The amount of swivel is quite limited in the device shown in this patent.
U.S. Pat. No. 4,099,801 discloses a spherical seat hydrostatic bearing that depends on a continuous flow of high pressure fluid to function.
U.S. Pat. No. 3,314,336 illustrates a "compression only" swivel which, again, has a sealing surface that does not rotate with the axis of the cylinder, which causes side loading of the ball used relative to the socket. High torque is required to overcome this friction when the joint swivels. Further, the bearing device does not have any type of a "floating" piston, which means that the pressure in the bearing tends to become increasingly out of phase with the pressure in the cylinder that is being used with the bearing as frequency increases. Considerable leakage also will be experienced in this device as the ball shifts across the socket due to phase differences in that there is no positive seal of the swivel chamber. The pressure in the swivel is exactly the same as the pressure in the cylinder being used, which limits the size of the parts that can be designed. Limited swiveling also appears to be a problem with this type of device.
U.S. Pat. No. 3,169,807 shows a spherical air or fluid bearing without any seals or pressure compensation. Two other patents of general interest to hydrostatic bearings on cylindrical objects with O rings extending around the cylinder to form generally sealed annular chambers included U.S. Pat. Nos. 3,360,309 and 3,863,995.
Pressure balanced hydrostatic bearings which permit sliding movement between planar surfaces, and which accommodate a limited amount of swiveling are shown in U.S. Pat. No. 3,921,286. The device shown includes a sealed area on the outer planar surface of a piston that is used to contain fluid under a pressure which is a function of the pressure under the piston. U.S. Pat. No. 3,994,540 shows a pressure compensated bearing wherein a sealed area forming a hydrostatic pad is maintained at a pressure equal to the pressure under the piston of the bearing. The pressure in the bearing is controlled by means sensitive to shifts in position between the supported object and a supporting surface at a location which is spaced from the actual support bearing itself.
In both of these devices, planar support surfaces for permitting sliding movement between two objects are disclosed. No spherical seat which has a sealed pressure area reacting against a socket or mating spherical surface is shown.
SUMMARY OF THE INVENTION
The present invention relates to a zero backlash swivel connection used primarily with hydraulic cylinder loading devices. The swivel may use a piston that has a part spherical outer surface mating with a part spherical surface on a supported member. As shown, preferably a sealed pressure area or chamber is defined between the two mating part spherical surfaces. This sealed pressure area is provided with a fluid pressure sufficient so the load exerted is supported on a film of fluid under pressure while permitting universal swiveling during loading. By universal swiveling, it is meant that the two surfaces carrying the load can pivot about mutually perpendicular axes relative to each other for at least a limited number of degrees. When pistons are provided the oil film is not necessary if a suitable bearing material is used for one of the spherical surfaces.
In specific forms of the invention, various means for developing the necessary pressure to carry the load exerted are shown. If the sealed pressure areas are provided with pressure proportional to the load exerted, the backlash will be taken up by the fluid layer in the sealed areas and no pistons are needed. The volume of oil between the spherical surfaces form a hydraulic or fluid backlash takeup cushion, even where loads are cyclic and reversed. Makeup oil can be provided by a separate pressure source.
The device thus permits high loads to be carried with small bearing surfaces, and because the active area carrying the loads can be subjected to high pressures, the parts can be kept relatively small while maintaining the advantages of quite wide ranges of swiveling without friction problems between the mating surfaces while eliminating backlash.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view through a typical schematic showing of a fluid pressure swivel joint made according to the present invention and taken generally along line 1--1 in FIG. 2;
FIG. 2 is a sectional view taken as along line 2--2 in FIG. 1;
FIG. 3 is a plan view of the spherical surface of the central member shown in FIG. 2 and a sectional view through the outer housing portion, taken generally along the line 3--3 in FIG. 2; which extends upwardly over the part spherical surface;
FIG. 4 is a sectional view of a typical swivel connection and a schematic representation of an active hydraulic fluid makeup circuit for the swivel; and
FIG. 5 is a sectional view of a modified form of the swivel showing another form of active hydraulic fluid makeup circuit for the swivel.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first primarily to FIGS. 1 through 3, a swivel joint connection illustrated generally at 10 made according to the present invention includes a first load applying yoke member 11 which is connected through a suitable connection such as a shaft 12 to a hydraulic actuator, schematically shown at 32, and which includes a cross pin or support indicated generally at 13 that extends between spaced legs of the member 11. The cross pin 13 as shown has a cylindrical recess or hydraulic cylinder 14. The oppositely facing surface of the pin 13 has a raised, fixed boss 15 thereon centered on the axis of the cylinder 14. The central axis of cylinder 14 and boss 15 extend along the axis of loading, which is indicated generally at 16 in FIGS. 1 and 2. The wall of the cylinder 14 is not very long in axial direction, but is sufficiently long to support and hold a spherical outer surface piston member 20. The piston member 20 has a cylindrical outer wall that slidably fits within the cylinder 14, and a seal 20A is used for sealing the outer cylindrical wall of the piston member 20 with respect to the cylinder 14. The boss 15 has a part spherical outer surface 21 which corresponds to the shape of the outer end of piston member 20.
There is a chamber 20B formed beneath the bottom of the piston member 20 and the bottom wall of the associated cylinder 14. The bottom wall of the cylinder 14 is defined in the cross pin 13.
The outer part spherical surface of the piston member 20 and surface 21 are both positioned within and mate with an inner surface defined in an opening of a second member 22 that is formed like an eye, and which forms a loaded member. The pin 13 extends through the opening. The loading yoke or member 11 as shown has spaced apart legs between which the member 22 passes. The member 22 can rotate around the axis 23 of the pin 13 and member 22 can also swivel about the axis 16 as well as being able to tilt relative to the axis 16 and the axis 23 about the intersection point of the axes 16 and 23, which is the center of the spherical surfaces that are used.
While substantial space is shown in the drawings in some instances to indicate chambers and clearances, the actual clearances are small. The outer part spherical surface of the piston member 20 and the part spherical surface 21, as well as the part spherical inner surface 22A of the eye member 22 that mates with spherical surfaces of the piston 20 and boss 15 have common centers at the intersection between axes 23 and 16.
The piston member 20 has a seal installed in a circular groove formed in the outer surface thereof and the surface 21 also has a seal installed in a circular groove defined therein. Each seal defines a circular chamber on a portion of the surface. A first seal 25 is shown mounted in a groove on piston 20, and as shown in FIG. 1 the plane of this seal is substantially a chordal plane of the spherical outer surface of piston 20. As best seen in FIG. 3, seal 25 defines a chamber indicated at 25A that is within the periphery of the seal 25 and between the inner surface 22A of member 22 and the outer surface of piston 20.
A seal 26 is positioned in a groove provided on the outer surface 21 of the boss 15. Seal 26 engages the aligning portions of the inner surface 22A of member 22 to define a chamber 26A that is enclosed by seal 26.
The seal 26 defines chamber 26A at the lower end portion of the load applying eye member 22. The load applying eye member 22 is similar to a rod end. It should also be noted that the seals 25 and 26 are substantially centered on the axis of loading of member 11 and on the axis of the piston 20.
In order to provide a fluid pressure bearing in this swivel connection, the chamber 25A is open through a passageway 25B to a lower chamber 20B beneath the piston 20, which in turn is open to a suitable passageway 30 defined in the pin 13. The passageway 30 is connected to a conduit 31 which leads to the chamber 31A which is pressurized in an actuator 32 driving member 11, when rod 12 and member 11 are moving upwardly, as illustrated schematically. Once the conduit 31, passageway 30, chamber 20B, passageway 25B and chamber 25A are filled with fluid, pressure developed in chamber 25A will be proportional to the pressure in chamber 31A and thus to the load that is applied between the members 11 and 22.
Likewise, for the boss 15 and surface 21, the chamber 26A formed within the periphery of the seal 26 is open through a passageway 33 to a conduit 34 leading to the chamber 34A in actuator 32 which is pressurized when the rod 12 and member 11 are moving downwardly. The pressure in chamber 26A is proportional to the tension load applied to rod 12 and members 11 and 22 from the pressure in chamber 34A. Makeup oil to accommodate leakage that occurs past the seals is provided by the fluid in the actuator 32. The effective area of the piston 20 can be correlated to the effective area of the piston in actuator 32 to develop the necessary pressure for operation with zero backlash and with an adequate fluid layer in chambers 25A and 26A for a hydrostatic bearing.
The system of FIG. 1 will work with one piston as shown, and will also work with no pistons. That is, piston 20 would be eliminated and a fixed part spherical surface would carry seal 25 to form the chamber 25A. One piston also can be used with pressure intensifiers as shown in a subsequent form of the invention. As a further modification a piston such as 20 can be used for taking up backlash, but seals 25 and 26, chambers 25A and 26A and passageways 25B and 26B may be eliminated, with a low friction material being provided on or between mating surfaces 22A and the outer surface on the piston and surface 21. Pressure in chamber 20B could force the piston outwardly to provide zero backlash. The swivel would not have as low friction, however, as with hydrostatic bearings being formed. The piston 20 used also may be mounted in member 22 rather than member 11. The area of the piston in chamber 20B is larger than the area of chamber 25A defined by seal 25. The differential in size is controlled to be relatively small to insure adequate area in chamber 25A to minimize friction load.
Thus the structure shown in FIGS. 1 through 3 provides for a swivel joint that reacts loads substantially on fluid under pressure that is within the sealed chambers 25A and 26A, each formed between two part spherical surfaces. The fluid under pressure preferably is a hydraulic oil, and the swiveling takes place so that the loads are carried along the axes intersecting at the centers of the part spherical sealed chambers that carry the loads so that there is substantially no friction between parts that must swivel under this load. An outer race is formed around the piston and surface 21 by the interior surface 22A of the loading member 22, which also may rotate around the pin 13 about axis 23 for alignment purposes. The amount that the piston 20 has to move in its cylinder in order to accommodate the load application in both tension and compression is relatively low. Thus a completely sealed bearing that carries load under hydraulic or hydrostatic pressure without flow of fluid through the bearing is provided.
FIG. 4 shows a modified device substantially similar to that shown in FIGS. 1 through 3, but this particular device provides for high pressure fluid as the makeup supply. In this unit, a load carrying swivel 48 includes a first loading member or yoke indicated generally at 51 which is connected through a load cell 52 to an actuator that is represented by a block 49. The first loading member 51 has a pin 53 which has first and second cylinders 54 and 55 corresponding to the cylinders 14 and 15 defined therein. The pin or support 53 is a cross pin that passes through the opening of a second loading eye member 62 that reacts the load. The cylinders 54 and 55 again have cylindrical walls formed around a central axis indicated at 56. Cylinder 54 has a first piston member 60 mounted therein and cylinder 55 has a second piston member 61 mounted therein. The pistons correspond to the piston members 20 and 21. Seals 60A and 61A on the side walls of the pistons are used for sealing the respective pistons within their cylinders as previously explained. The second, loading member 62 has a part spherical inner surface 62A which surrounds the outer part spherical surfaces of the pistons 60 and 61. The pistons 60 and 61 in this form of the invention also have seal members 65 and 66 on the outer surfaces thereof. Seal members 65 and 66 define circular enclosed areas, respectively, which form small chambers 65A and 66A between the inner surface 62A of the member 62 and the outer surfaces of the respective piston. The surface 62A forms an outer race over the bearing piston members 60 and 61.
The pistons 60 and 61 can move axially along the direction of the axis 56 a short distance, as in the previous forms of the invention. The chambers formed at 65A and 66A are open through passageways 65B and 66B, in the respective piston to the inner ends of the respective cylinders. The inner end of cylinder 54 is connected through a passageway 70 in the pin 53, to the exterior of the assembly, and the passageway 66B which is open to the pressure area 66A also aligns with and is open to the inner end of cylinder 55 and through a passageway 73 in pin 53 to the exterior of the assembly.
In this particular instance, however, a different means of providing makeup oil to the high pressure areas 65A and 66A is shown. Passageway 70 is connected through a conduit 71 to a pilot operated blocking valve 72 that prevents flow outward from the passageway 70 and line 71 (due to high pressure in chamber 65A) and permits inflow only when a pilot pressure has been supplied to the blocking valve control portion 72A. The blocking valve 72 is connected to a high pressure source 74 through suitable conduits.
Passageway 73 is connected through a suitable conduit 75 to a second pilot operated blocking valve 76, the input of which is also connected to the high pressure source 74. By high pressure source, it is meant that the pressure source has a pressure that is at least equal to the pressure in the chambers 65A and 66A necessary to react the loads between actuator 49 and load member 62. The pressure of source 74 is determined by the load capacity of the actuator 49 and the area of chambers 65A and 66A and can be selected as desired.
The pilot operated blocking valves 72 and 76 are each connected so that their pilot stages indicated at 72A and 76A, respectively, are coupled to external valves. The valve controlling pilot stage 72A is shown at 77, and is a solenoid valve, which when energized will open a conduit 78 leading to pilot stage 72A from a suitable pressure source, and in its normal condition (unenergized) conduit 78 is opened to a return or drain. The pilot operated blocking valve 72 will not permit fluid flow through the blocking valve into conduit 71 when the pilot stage 72A is not pressurized.
The pilot stage 76A of valve 76 is connected to a solenoid valve 80, which also is of the same form as valve 77, and when energized the valve 80 connects the pilot stage 76A to a conduit 81 which is connected to a pressure source.
In order to determine whether makeup oil should be supplied to chambers 65A or 66A, a differential pressure sensor indicated generally at 83 is connected between the conduits 71 and 75. The pressure sensor provides an electrical output along line 84 to a comparator 85. The signal on line 84 of course depends upon the differential pressure between the two lines. A second input of comparator 85 is connected along a line 86 to the load cell 52. Both the load cell and sensor 83 provide a plus signal in tension and a minus signal in compression. If the differential pressure signal on line 84 is less than the load cell signal on line 86, the comparator 85 provides an output and makeup oil will be provided. The polarity of the signal determines which solenoid is energized. A plus output from comparator 85 energizes valve 80 and causes pilot stage 76A to be pressurized thereby opening the blocking valve 76A and providing fluid under high pressure from source 74 through line 75 to passageway 73 and thus to the chamber 66A. Makeup oil is provided because the signals indicate the likelihood of metal contact between the piston 61 and the aligning portions of surface 62A of second member 62.
If the differential pressure signal and the load cell signal are equal, both the solenoid valve 77 and 80 are relaxed. However, if comparator 85 provides a negative output, the solenoid valve 77 will energize thereby activating the pressure source to line 78 and to pilot stage 72A to open pilot operated blocking valve 72 and provide a flow of fluid through conduit 71 from the pressure source 74 and into passageway 70 and thus to chamber 65A.
It should be noted that the pilot operated blocking valves and high pressure source arrangement can be used in both tension and compression loads, and the proper makeup oil direction is provided automatically. Also, suitable control circuits may be supplied between comparator 85 and the solenoid valves if desired to achieve proper operation.
In FIG. 5, a further modified form of the present invention is shown. A swivel assembly illustrated generally at 100 uses only one movable piston in the hydraulic swivel assembly. As shown, a double acting hydraulic actuator is indicated generally at 101 and has an internal piston 102, acting within a cylinder to load an output rod 103. A first loading member 104 which is formed like a yoke is connected to the rod 103. A cross pin or support 105 is carried by yoke 104. The pin 105, as shown has a part spherical raised surface 106 on one side thereof centered along the axis of loading passing through the rod 103. This is an integral or fixed surface that is formed as part of the pin 105.
A seal 107 is placed in a groove on surface 106 to define a pressure area 107A surrounded by this O ring in the same manner as the seal in the previous forms of the invention. The seal 107 is centered about the axis of loading of member 104.
A second loading member 110 encircles the pin 105 as in the first form of the invention and can be formed like an eye. The member 110 has an interior part spherical surface 110A which mates with the surface 106 and forms an outer race for the fluid bearing. Both of the part spherical surfaces 110A and 106 have the same center so that the two loading members can swivel relative to each other. The seal 107 thus defines a sealed area 107A between the encircled, sealed area and the interior surface 110A of the member 110.
On the opposite side of the pin or support 105 from surface 106, and also centered on the axis of the actuator rod 103, there is a cylinder 111 defined in the pin. The cylinder 111 has a cylindrical peripheral wall and a piston member 112 is mounted within this wall and slidably sealed relative to the wall with a seal 113. The outer surface 112A of the piston 112 is part spherical and mates with the interior surface 110A. A seal 114 defines a circular enclosed area on the part spherical outer surface 112A on the piston 112 and this defines a chamber 114A between surfaces 110A and 112A, as shown in FIG. 5.
The chamber 114A opens through a passageway 114B in piston 112 to passageway 120, and chamber 107A is open to a passageway 121 in the pin 105. In this particular instance, the fluid under pressure to the chambers 107A and 114A is provided through pressure intensifiers that provide a pressure proportional to and greater than the pressure on the respective sides of the piston 102 within the actuator 101. For example, passageway 121 is connected through a conduit 122 to an intensifier 123 which has a first chamber 124 open to a piston 125 which is also then mounted on a rod slidably mounted in the chamber 126. The end of the rod forms a smaller piston area than the area of the piston 125. The fluid under pressure coming into the chamber 124 through a conduit 127 and acting on the piston 125 will compress any fluid in the chamber 126 at a higher pressure than the pressure in line 127 because of the differential in area causing a pressure in conduit 122 and in chamber 114A.
Limit switches can be used for controls to valves providing makeup oil to the intensifier 123. When the piston 125 and its attached rod move to a point where the chamber 126 is substantially reduced in volume, a limit switch 130 will be actuated, which in turn will energize a valve 131 to provide fluid under pressure along a conduit 132 to the intensifier for makeup oil. When the piston 125 has been moved back to substantially the end of chamber 124. A second limit switch 133 will close venting the solenoid valve.
Likewise, passageway 120 is connected through a conduit 135 to a pressure intensifier 136 which includes an interior chamber 137 having a piston 138 therein. The chamber 137 is connected through a line 140 to the opposite side of the piston 102 from line 127, and upon pressure being applied through line 140 to act on piston 138, a second chamber 142 will be subjected to a higher pressure because of the differential in areas between the end of the rod in the chamber 142 and the piston 138. This higher pressure will be provided along the conduit 135 to the chamber 114A. Again, in this instance a limit switch 147 will be actuated when the chamber 142 is reduced in volume. The limit switch will operate a valve 148 to provide fluid under pressure along a line 149 to the pressure intensifier, moving the piston 138 back to reduce the volume of chamber 137 until such time as a limit switch 150 is closed, venting the valve 148. The limit switches 130, 133, 147 and 150 can be used to sense some exterior portion of the movable member 138 or 125 and the attached rod, but they are shown only schematically in the enclosed drawings.
The valves 131 and 148 are three way, closed center solenoid valves and when neither of the controlling limit switches for a valve is closed, the respective valve blocks off flow to the intensifier it controls.
The effective area of the chamber formed by the seals on the exterior of the pistons is less than the area of the base of the pistons within the cylinder, so the pressure urges the pistons outwardly to maintain an adequate seal. The difference in size of these areas is actually kept quite small, and can be selected to insure maintaining an adequate hydraulic pressure in the chambers at the piston exteriors for supporting the loads encountered.
Multiple pistons (more than two) may be used in suitable pairs to provide balanced load carrying capabilities in a swivel in all directions as well as along the load axis as shown.
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A swivel joint which has two mating part spherical reaction surfaces carried on two loading members. One of the surfaces is defined in part on a piston which is urged under pressure toward the mating part to take up backlash between the mating surfaces. A sealed area may be defined between the mating surfaces and which contains a quantity of fluid under pressure to carry the loads between the two surfaces on a hydrostatic bearing. The swivel joint permits high loads from hydraulic actuators to be supported without encountering high friction forces while permitting swiveling of the joint across a substantial range of angles.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to an improvement of a protective bag and hard shell system to properly and safely carry, transport and store a thin, fragile monitor or load of varying sizes. The disadvantage with existing systems is none can safely carry a thin, fragile, expensive monitor or load of varying lengths, sizes and weights, whether it is Liquid Crystal Display (LCD), Light Emitting Diode (LED), Plasma, Digital Light Processing (DLP), Laser or an unknown technology yet to come. These are all a rather new technology, explaining why no proper carrying and storage system has been invented until ours. Until the inconvenience of properly carrying, transporting, protecting and storing a thin, fragile, expensive monitor or load of varying lengths, sizes and weights is solved, people will need to continue carrying them by hand, using improper hand holds if any, cover them with cloth or blankets, balance them on a conventional cart, risk scratching the surface, risk slipping improper grip or hand holds, risk damage in storage or risk damage during vehicle transportation by poor tie down systems if any, foreign objects sliding or falling against it from turning or vehicle vibration. The larger units can weigh over 100 pounds with no proper hand holds and all monitors are fragile, presenting a risk of damage and scratching the units and or the fragile, delicate and or expensive building surroundings and or to the person or persons carrying it, during moving or transporting the fragile load too and from it's two or more points of location. This will continue to cost more in company expenses to absorb losses including: insurance claims for damaged units; building floor, wall, and doorway surfaces; and workers compensation claims for workers injured improperly carrying the units.
SUMMARY OF THE INVENTION
[0002] In order to rectify the existing disadvantages of the conventional or none existent system of protecting, carrying, transporting and storing a thin, fragile monitor or load of varying sizes and weights as described, the applicants have been consistently and continuously making efforts to develop and improve the type of system required for this need. With the applicants' accumulated experience and intelligent skills in the field, the applicants finally devised protective bag and hard shell system to properly and safely carry, transport and store a thin, fragile monitor or load of varying sizes and weights in an upright position.
[0003] It is an object of the present invention to provide a protective bag that provides proper hand holds no matter what the load provides if anything and to provide a heavily cushioned platform or base, medium cushioned lower end and thinly cushioned and more flexible upper end of bag to better conform to the shape and size of the load to better protect the monitor or load of varying sizes and weights and to better protect the surroundings the bag and load are carried through and with tapered ends to help the bag slide into the protective shell.
[0004] It is another object of the present invention to provide a hard shell or exoskeleton system that can be secured to the inside of a vehicle or stacked in a warehouse or shop to properly and safely hold the protective bag containing a thin, fragile monitor or load of varying sizes and weights in an upright position for safe, secure and proper vehicle transport and warehousing or shop storage of the bag and load with rounded side vertical support frame tubes to assist the bag and loads sliding in.
[0005] It is a further object of the present invention of a protective bag and hard shell exoskeleton system to be made of a strong enough and lightweight enough material to hold the load safely and minimize weight. Keeping assembly to a minimum to reduce production and shipping costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a three dimensional, side perspective view of the Monitor Transporting system showing the soft cushioned bag fully inserted in the rigid protective exoskeleton shell according to the present invention.
[0007] FIG. 2 is a three dimensional, side perspective view of the Monitor Transporting system showing the soft cushioned bag partly inserted or retracted from the rigid protective exoskeleton shell according to the present invention.
[0008] FIG. 3 is a three dimensional, side perspective view of the rigid protective exoskeleton shell according to the present invention.
[0009] FIG. 4 is a three dimensional, exploded view of the rigid protective exoskeleton shell according to the present invention.
[0010] FIG. 5 is a three dimensional, side end perspective view of the soft cushioned bag according to the present invention.
[0011] FIG. 6 is a three dimensional, side end perspective cutaway view of the soft cushioned bag according to the present invention.
[0012] FIG. 7 is a two dimensional, bottom view of the soft cushioned bag showing the torpedo or tapered shape of the soft cushioned bag according to the present invention.
[0013] FIG. 8 is a two dimensional, top view of the soft cushioned bag showing the internal load or monitor straps within the soft cushioned bag according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] FIG. 1 shows a complete Monitor Transporting System according to a preferred embodiment of the present invention wherein the soft cushioned bag ( 5 ) is fully inserted into the rigid protective exoskeleton shell ( 1 ) by sliding in with the aid of lower side guides ( 2 ), upper side guides ( 3 ) and rounded vertical rigid frame supports (la) to avoid the soft cushioned bag from catching on the frame of the rigid protective shell.
[0015] FIG. 2 shows the Monitor Transporting System according to a preferred embodiment of the present invention wherein the soft cushioned bag ( 5 ) is partly inserted into or retracted from the rigid protective exoskeleton shell ( 1 ) with the aid of handle ( 9 ) for pulling the bag from the rigid frame or by sliding in or out with the aid of lower side guides ( 2 ), upper side guides ( 3 ) and rounded vertical rigid frame supports ( 1 a ) to avoid the soft cushioned bag from catching on the frame of the rigid protective shell.
[0016] FIG. 3 shows the rigid protective shell according to a preferred embodiment of the present invention wherein the soft cushioned bag is not in the rigid protective exoskeleton shell ( 1 ) reveling the lower bag guilds ( 2 ) the upper bag guilds ( 3 ) and the bottom slide plate ( 4 ) for sliding the soft cushioned bag and load in or out.
[0017] FIG. 4 shows an exploded view of the empty rigid protective exoskeleton shell ( 1 ). Visible are the bottom slide plate ( 4 ) for sliding the soft cushioned bag onto, the upper and lower section of the frame ( 1 b ) and ( 1 d ), the back or rear of the frame or shell ( 1 c ) and the lower ( 2 a ) and ( 2 b ) and upper ( 3 ) side guides and round tubular vertical frame supports ( 1 a ) to help the soft cushioned bag and load to slide in with out catching on sharp corners.
[0018] FIG. 5 shows the soft cushioned bag ( 5 ) wherein visible are; outside bag material ( 6 ) is of a durable water resistant flexible material, inside lining bag material ( 7 ) is of a soft very flexible material to help prevent scratching the load or monitor, handle strapping material ( 8 ) runs from one handle to the opposite handle for extra strength, pull handle ( 9 ) for pulling the bag from the rigid protective shell, carrying handle ( 10 ) for caring bag with load having a proper center of gravity to help keep the load and bag in an upright or vertical position while carrying and lower handles ( 11 ) for maneuvering the bag with load for loading, unloading and positioning and adjustable load securing straps ( 12 ) that travel through one side of the bag to the other near each end to help secure and center the load or monitor within the bag.
[0019] FIG. 6 shows a cutaway view of the soft cushioned bag ( 5 ) wherein visible are; outside bag material ( 6 ) is of a durable water resistant flexible material, inside bag lining material ( 7 ) is of a soft very flexible material to help prevent scratching the load or monitor, adjustable load securing straps ( 12 ) that travel through one side of the bag to the other near each end to help secure and center the load or monitor within the bag, heavy rigid bottom cushion ( 13 ) to protect the load or monitor within the bag from bottom damage or screen damage due to bottom shock, medium semi rigid lower side cushions ( 14 ) to protect the internal load or monitor from damage due to side shock and thin flexible upper cushion ( 15 ) that can easily lay or flap over the load or monitor to protect the upper section of the load or monitor from dings, scratches and weather.
[0020] FIG. 7 shows the bottom of the soft cushioned bag ( 5 ) wherein the handle strapping ( 8 ) runs from one handle to the opposite handle for extra strength and the torpedo or tapered shape of the bag for easier loading into and to avoid catching on sharp corners on the rigid protective shell.
[0021] FIG. 8 shows an upper view looking down into the soft cushioned bag ( 5 ) wherein the adjustable load securing straps ( 12 ) that travel through one side of the bag to the other near each end to help secure and center the load or monitor ( 16 ) within the bag can be seen.
FIELD OF THE PRESENT INVENTION
[0022] The present invention relates to a soft cushioned bag and rigid rectangular shell to safely transport thin, fragile monitors of varying size. The bag and rigid shell of the present invention is a novel, practical and safe transportation and storage means, protecting from damage and scratches which has the advantages of easy operation, simple in construction and suitable for safely carrying, transporting and storing monitors and fragile loads of various weights and sizes. The monitor or load can be taken right from its place of origin, placed in the bag, carried using the hand holds provided by the bag too and placed in the rigid rectangular shell for further transport or storage. The rigid shell can be used for safe protective storage of the monitor or load in a building for storage protection or in a vehicle for further transport protection.
Field of Search
[0000]
150/52.7,25,2.2,48,2 292/283,284 24/73PA
280/47.131, 280/47.23, 47.24, 47.26, 47.27, 63, 79.11, 280/79.2, 79.7
190/2; 383/4; 5/417; 224/155; 156,577
280/47.25, 280/47.24, 32.5, 47.19, 47.35, 47.38, 47.17, 280/63, 47.131, 47.34, 124.12, 137.501
190/109; 383/4; 5/417; D6/582; D6/596
5/630,632,633,636,637,638,640,644,652,652.1,653,654,655,655.3,655.4,655.5
D3/216,217,274,276,289
190/1,2,8,9 383/4,3 5/417,420,462,466 297/129,217,188,118 150/6
150/29,31,1.7,12,51,DIG.1,33 190/2,8,49,1175/419 229/52A,54C 220/95
248/95,74.3,74.5 297/350,377,441 383/4,12,15
383/61.1; 383/41; 383/905; 383/91
References Cited
[0000]
U.S. Pat. No. 3,827,471 Gregory Sep. 18, 1972
U.S. Pat. No. 7,222,705 B1 Guza May 29, 2007
U.S. Pat. No. 7,229,081 B2 Stockler Jun. 12, 2007
U.S. Pat. No. 7,316,407 B1 Elden Feb. 8, 2007
U.S. Pat. No. 1,951,527 Hill Mar. 20, 1934
U.S. Pat. No. 2,540,165 Fiel Feb. 6, 1951
U.S. Pat. No. D474,934 Ildstad and Cotton May 27, 2003
U.S. Pat. No. 4,863,003 Carter Jun. 17, 1988
U.S. Pat. No. 4,466,517 Spiegelman Feb. 8, 1982
U.S. Pat. No. 2,384,974 Smith Sep. 18, 1945
U.S. Pat. No. 2,071,745 Higginbottom Feb. 23, 1937
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Protective soft cushioned bag providing hand holds to safely contain, protect and carry a monitor or load of varying sizes and weights from the original site of the monitor or load to the rigid protective rectangular exoskeleton shell for transportation to another location or secure storage and vise versa.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a gas turbine blade composed of two or more components made from different materials, and more particularly to a formulation used in the construction of a lightweight jet engine fan blade.
2. Discussion of the Prior Art
Gas turbines include, but are not limited to, gas turbine power generation equipment and gas turbine aircraft engines. A gas turbine includes a core engine having a high pressure compressor to compress the air flow entering the core engine, a combustor in which a mixture of fuel and the compressed air is burned to generate a propulsive gas flow, and a high pressure turbine which is rotated by the propulsive gas flow and which is connected by a larger diameter shaft to drive the high pressure compressor. A typical front fan gas turbine aircraft engine adds a low pressure turbine (located aft of the high pressure turbine) which is connected by a smaller diameter coaxial shaft to drive a front fan (located forward of the high pressure compressor) and to drive an optional low pressure compressor (located between the front fan and the high pressure compressor). The low pressure compressor sometimes is called a booster compressor or simply a booster.
The fan and the high and low pressure compressors and turbines have airfoils each including an airfoil portion attached to a shank portion. Rotor blades are those airfoils which are attached to a rotating gas turbine rotor disc. Stator vanes are stationary airfoils which are attached to a non-rotating gas turbine stator casing. Typically, there are alternating circumferential rows of radially-outwardly extending rotor blades and radially-inwardly extending stator vanes. When present, a first and/or last row of stator vanes (also called inlet and outlet guide vanes) may have their radially-inward ends also attached to a non-rotating gas turbine stator casing. Counterrotating “stator” vanes are also known.
Conventional airfoil designs used in the compressor section at the engine typically have airfoil portions that are made entirely of metal, such as titanium, or are made entirely of a composite. A “composite” is defined to be a material having any (metal or non-metal) fiber filament embedded in any (metal or non-metal) matrix binder, but the term “composite” does not include a metal fiber embedded in a metal matrix. The term “metal” includes alloys such as titanium Alloy 6-2-4-2. An example of a composite is a material having graphite filaments embedded in an epoxy resin.
The all-metal blades, including costly wide-chord hollow blades, are heavier in weight which results in lower fuel performance and require sturdier blade attachments, while the lighter all-composite blades are more susceptible to damage from bird ingestion events. Known hybrid blades include a composite blade having an airfoil shape which is covered by a surface cladding (with only the blade tip and the leading and trailing edge portions of the surface cladding comprising a metal) for erosion and foreign object impacts. The fan blades typically are the largest (and therefore the heaviest) blades in a gas turbine aircraft engine, and the front fan blades are usually the first to be impacted by foreign objects such as birds. What is needed is a lighter-weight gas turbine blade, and especially an aircraft-engine gas turbine fan blade, which is both lighter in weight and better resistant to damage from ingestion of foreign objects and blade out events.
SUMMARY OF THE INVENTION
The present invention is a formulation which can be cured onto a metal aircraft engine fan blade, thereby making the blade lighter, without sacrificing any of the structural integrity of the blade, that is, its resistance to foreign object impacts and the like.
The formulation comprises a polyurethane elastomer composition, formed by adding an anti-oxidant to a curative, melting the resultant composition, and mixing the composition. The curative with anti-oxidant is then mixed with a prepolymer, thereby forming a polyurethane composition, and cast into a preheated mold. The mold holding the polyurethane is placed into an oven at a predetermined temperature for a predetermined period of time, and thereafter, the polyurethane is demolded and placed into an oven at a predetermined temperature for a predetermined period of time sufficient to cure the polyurethane elastomeric composition.
Each mold is formed by a cavity within the metallic fan blade in the form of a pocket and a removable caul sheet. Each fan blade may have a plurality of pockets. The caul sheet is a composite that is affixed to the fan blade so that each of the pockets is temporarily enclosed. The caul sheet includes at least one injection port to provide a flow path for the uncured elastomer into the pockets, which have assumed the shape of a mold with the attachment of the composite caul sheet. The details of the injection system are the subject of co-pending application identified as Attorney Docket 13DV-12944 assigned to the Assignee of the present invention, incorporated herein by reference. After the polyurethane elastomeric composition is injected through at least one injector port into the mold, the elastomer is cured.
In one alternate embodiment, an anti-oxidant and/or a hindered amine light stabilizer and/or an ultraviolet absorber are optionally added to the curative. These chemical formulations assist in preventing deterioration of the blade as a result of exposure to radiation from the sun and exposure to the atmosphere as desired, thereby, when included, extending the life of the elastomer and the blade. Thus, the combination of additives can provide high temperature optimization and environmental protection.
An advantage of the present invention is that the polyurethane elastomer can be cured directly to the blade. Because the pockets form part of the mold, the polyurethane elastomer mates with essentially 100% of the available interface surface area of the blade. Because of the excellent adhesive characteristics of the elastomer to the metal, the maximization of the surface area contact between the elastomer and the metal provides for a strongly bonded insert.
Another advantage of the present invention is that since the polyurethane elastomeric insert is cured in place, there is no misfit between the pocket and the blade so that the blade having the cured elastomeric insert is aerodynamic, with little or no trimming required to remove excess material. This permits unimpeded flow of air entering the compressor while allowing the blade to operate at temperatures up to 310° F.(155° C.).
Another advantage of the present invention is that the blade having the cured elastomeric inserts is significantly lighter than a corresponding blade comprised solely of a metallic alloy, yet provides aerodynamic stability of such a blade. This weight advantage provides a corresponding improvement in fuel efficiency of the engine without adverse effects on performance.
Still another advantage of the present invention is the cost savings associated with replacing expensive metallic alloys such as titanium alloys with inexpensive polyurethane elastomers.
Finally, the present invention provides an advantage over a system in which elastomers are cured and then assembled into the pockets with an adhesive, since the time consuming and labor intensive step of adhesive bonding is eliminated and the potential for unbonded interfaces between the elastomer and the blade pocket is greatly reduced. The current system is self-adhesive and problems with fit-up are eliminated.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective of an aircraft engine fan blade, showing pockets formed therein;
FIG. 2 is a perspective of the injection system utilized in the present invention; and
FIG. 3 is a schematic cross-sectional view of the injection system of FIG. 2, taken along lines 3 — 3 of FIG. 2 .
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, wherein like numerals represent like elements throughout, FIG. 1 schematically shows a aircraft engine fan blade 10 used in the preferred embodiment of the present invention. The fan blade 10 is made from a metal, typically a titanium alloy such as Ti 6-2-4-2 and has a convex side and a concave side. Six pockets 12 typically are manufactured into the concave (pressure) side 14 , as shown in FIG. 1 . The number of pockets is dependent upon the configuration and size of the blade, and fewer or more pockets may be included as necessary. The pockets may be formed in the blade by any conventional means, such as by machining. Conveniently, the blade may be forged with the pockets being an integral part of the forged configuration. In accordance with the process of the present invention, a caul sheet 16 is fitted, such as by clamping, to the contour of the concave side 14 of fan blade 10 , as shown in FIGS. 2 and 3, and is sealed with an O-ring 19 , which is retained in a groove around the periphery of caul sheet 16 , as shown in FIG. 3 . The caul sheet 16 is preferably made from a composite material, such as carbon fiber filaments embedded in an epoxy resin. Caul sheet 16 is provided with a plurality of injection ports 18 , which are located on caul sheet 16 so as to correspond with the location of pockets 12 on fan blade 10 when caul sheet 16 is fitted on to fan blade 10 . Although caul sheet 16 is shown with a plurality of injection ports 18 , if there is communication among the pockets 12 in the blade 10 , a single injection port 18 may be utilized.
After the polyurethane elastomeric composition is prepared (described in more detail below), the composition is fed into an injection manifold 20 , as shown in FIG. 2. A plurality of tubes 22 lead from injection manifold 20 to injection ports 18 on caul sheet 16 , the number of tubes corresponding to the number of injection ports. The polyurethane elastomeric composition is then injected into each of the pockets 12 , and the pressure is maintained until the polyurethane is cured. The polyurethane elastomer typically is cured by exposure to a preselected, elevated temperature for a preselected time. However, certain polyurethane formulations that may be used in the practice of this invention do not require elevated temperature exposure, as they air cure at ambient temperatures. The pockets must be filled with polymer and cannot be left as a void space. If left as a void space, the aerodynamic characteristics of the blade are adversely affected, thereby modifying the flow characteristics of air into the engine, which may adversely affect engine operation. As the polyurethane elastomer cures, it forms a strong bond with the metal portion of the fan blade with which it is in contact. However, it does not form a strong bond with the composite caul sheet, the caul sheet being selected or treated so as not to bond with the polyurethane elastomer as it cures.
After curing, caul sheet 16 is removed, and the cured polyurethane elastomer in pockets 12 forms a portion of the concave side of fan blade 10 . This provides a fan blade which is much lighter than those blades made entirely of metal, due to the use of the low density polyurethane elastomer composition in the pockets which are molded into the metal blade. Further, because metal is nonetheless being used to a large degree, the strength of the blade and its resistance to bird strikes and other ingested foreign material is not sacrificed.
In a first preferred embodiment of the present invention, the composition which is utilized to lower the weight of the blade comprises a pre-polymer, a curative and an antioxidant. The process for incorporating the polyurethane elastomer into the blade first entails adding the anti-oxidant to the curative. These ingredients are then heated until melting occurs and they are thoroughly mixed to form a first mixture. A prepolymer of polyurethane, such as toluene di-isocyanate (TDI) capped polyether with an isocyanate functionality (NCO) content of 4.1-4.6%, is heated to its melting point. This prepolymer, also known as AIRTHANE® PET-91A, is available from Air Products and Chemicals, Inc. of Allentown, Pa. The first mixture is added to the prepolymer and thoroughly mixed to form a homogeneous second mixture. The second mixture is cast into a pre-heated mold. Referring to FIG. 2, the preheated mold is each respective cavity 12 of fan blade 10 formed after composite caul 16 is clamped and sealed to the fan blade. The fan blade is preheated to a temperature in the range of 210-250° F.(99-121° C.). The second mixture is cast into the cavities or pockets by an injector manifold 20 that injects the second mixture through injection ports 18 . After the pockets are filled with polymer, the polymer is held for a sufficient period of time to permit the polymer to gel in the pockets, typically about 5 minutes. After the polymer has gelled, the fan blade is placed into an oven at a temperature of about 210-250° F.(99-121° C.) for a time sufficient to permit cross-linking to at least partially develop within the polymer to provide sufficient rigidity to allow demolding of the polyurethane, that is, the removal of the composite caul sheet and associated tooling from the back or concave side 14 of the blade 10 while leaving the polyurethane within the pockets. This time is typically from about 0.5 to about 2 hours. The blade is then placed into an oven at a temperature of about 212-320° F. (100-160° C.) for about 16-50 hours for curing. Because of the loads experienced in aircraft engine fan blades, which can cause undesirable creep of the elastomer, it is preferable to fully cross-link the elastomer during curing to develop improved creep resistance.
In this embodiment, a preferred curative used with the preferred prepolymer is a diamine, a chain extender used in polyurethanes. One such curative is a bis-dianaline available through Air Products, Inc. through an arrangement with Lonza, Inc, under the trademark LONZACURE® MCDEA. A preferred antioxidant is N-phenylbenzamine, such as Ciba IRGANOX® 5057.
The stoichiometric ratio of curative to pre-polymer is approximately 90-100%. When included, anti-oxidant is added up to 1% by weight of the overall composition weight, and preferably 0.23-0.27% by weight of the composition, and most preferably about 0.25% by weight.
In a second preferred embodiment of the present invention, a hindered amine light stabilizer (HALS), such as TINUVIN® 765, and/or an ultraviolet absorber, such as TINUVIN® 571 are added to the first mixture of antioxidant/curative mixture prior to melting. The ultraviolet (UV) absorber and the HALS are included to extend the life of the polyurethane elastomer, since it will be exposed to light and ultraviolet radiation during operation. When included, the HALS is added up to about 1% of the overall composition weight, preferably about 0.46-0.50% of the composition weight and most preferably about 0.48% by weight. When included, the UV absorber is added up to about 1% of the overall composition weight, preferably about 0.22-0.26% of the overall composition weight and most preferably about 0.24% by weight. Both the preferred HALS, TINUVIN® 765, and the preferred UV absorber, TINUVIN ® 571, are available from Ciba Specialty Chemicals of Switzerland. The processing is otherwise identical to that specified above for the first embodiment.
In preparing the prepolymer for use, such as PET-91A, it may be necessary to melt it, particularly if the prepolymer has solidified. This may be accomplished by placing a drum of the material in an oven capable of holding it at a temperature in the range of about 100-140° F.(38-60° C.) until the prepolymer is fully melted. The prepolymer is then stirred and degassed using suitable equipment. Care is taken to prevent the prepolymer from contacting moisture, as moisture will adversely affect the material.
A desired amount of curative, such as those containing amino functionality, is weighed. In the preferred embodiment a diamine curative, such as LONZACURE® MCDEA in the appropriate amount is weighed. To the curative, a preselected amount of anti-oxidant, such as N-phenylbenzamine, is added to the curative. In the preferred embodiment, about 0.24% of IRGANOX 5057® is added. The UV absorber, in the preferred embodiment TINUVIN 571®, and the HALS, in the preferred embodiment TINUVIN 765® are added in suitable amounts to provide the required environmental protection. In the preferred embodiment, these are added in the amounts of about 0.24% and 0.48% respectively. The percentages are provided based on the total weight of the polyurethane composition. This first mixture is heated to a maximum temperature of about 250° F.(121° C.) for a time sufficient to melt the mixture. The melted mixture is then stirred to assure uniformity. This first mixture is then poured through a strainer into an uncontaminated tank, which is protected with an atmosphere of nitrogen sufficient to prevent atmospheric contamination, typically about 30-40 psi of N 2 .
The prepolymer tank and associated lines are heated to temperatures in the range of about 125-145° F.(52-63° C.), and the tank and lines for the first mixture are heated to temperatures in the range of about 215-235° F.(100-113° C.). After pumps are calibrated to assure that prepolymer and the first mixture will be dispensed to achieve a preferred stoichiometric ratio of 95-97% curative to an isocyanate functionality in the prepolymer, the lines are attached to a mixer and the materials are transferred from the tanks or containers to the mixer to assure a uniform second mixture. The second mixture is then transferred to an injection pump or injection manifold, after which it is injected onto the blade as previously discussed.
Although the present invention has been described in connection with specific examples and embodiments, those skilled in the art will recognize that the present invention is capable of other variations and modifications within its scope. These examples and embodiments are intended as typical of, rather than in any way limiting on, the scope of the present invention as presented in the appended claims.
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A formulation used in the construction of lightweight aircraft engine fan blades. The formulation comprises a polyurethane elastomer composition, which is formed from a prepolymer, a curative and an antioxidant and molded into the blades. Optionally, a hindered amine light stabilizer and/or an ultraviolet absorber may be added to the formulation.
The aircraft engine fan blade is formed from a metal, such as titanium alloy. Pockets are machined into the fan blade, so as to lessen the amount of metal used to construct the blade, thereby lowering the total weight of the blade. The formulation of the present invention is positioned in the pockets of the fan blade, so as to maintain the structural integrity of the blade against bird strikes and the like, while at the same time providing a fan blade which is significantly lighter than all-metal fan blades.
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FIELD OF THE INVENTION
[0001] The present invention generally relates to a steam distributor for applying steam to a continuously moving paper sheet wherein the steam distributor includes one or more drop-out steam profiling cartridges. Each cartridge, which is attached to the steam distributor with bolts, features a number of profiling zones that are covered by a contoured, smooth profiling screen from which steam is applied. Employment of drop-out cartridges affords quick and easy removal of the profiling screens for change-out or cleaning.
BACKGROUND OF THE INVENTION
[0002] The steam heating of a paper sheet is widely practiced in papermaking. The increase in sheet temperature that results provides increased drainage rates for the water thus reducing the amount of water to be evaporated in the drier section. Water drainage is improved by the application of steam principally because the heating of the sheet reduces the viscosity of the water, thus increasing the ability of the water to flow. Most of the heat transfer takes place when the steam condenses in the sheet. The condensation of the steam transforms the latent heat of the steam to sensible heat in the water contained by the sheet.
[0003] A particular advantage of the steam heating of the paper sheet is that the amount of steam applied may be varied across the width of the sheet along the cross machine direction so that the cross machine moisture profile of the sheet may be modified. This is usually carried out to ensure that the moisture profile at the reel is uniform. Techniques in the papermaking art for sensing the moisture profile of a sheet of paper are well known. If a sensing apparatus is positioned over the paper sheet, downstream of a steam distributor able to control the moisture profile, then after measuring the water profile in the sheet, steam can be applied in varying amounts on a selective basis across the sheet, thus achieving the required uniform moisture profile at the reel.
[0004] It is known to divide a steam distributor into compartments and to control the supply of steam to each compartment, thus controlling the moisture profile of the sheet. Fiber and dirt accumulate within the compartments and over time, the debris penetrates into the internal structures and interferes with steam flow. The steam distributor must be disassembled in order to clean the internal components.
[0005] U.S. Pat. No. 5,711,087 to Pazdera describes an apparatus for distributing steam to a paper web or calendar roll which includes a removable curved-shaped profile screen. The screen is mounted on the apparatus with clip members that interrupt the otherwise smooth exterior surface of the screen. In addition, the use of external clip members makes the removable screen susceptible to flexing outward with increasing steam pressure. Moreover, the clamped edge of the screens must often be separated from the clips on the frame using jarring force, then pried back into place. When they are reattached, the screens lose the intended tight fit against the baffles thereby allowing significant leakage between profiling zones. Finally, in these prior art designs where the screens are not permanently attached, the steam holes in the screen must be situated near either the leading or trailing edge of the steambox in order to minimize the machine direction (MD) length of the screen. Consequently, if a screen becomes too long in the MD, the screen tends to bow out which causes excessive and inconsistent leakage between profiling zones. These removable screen plates become warped and battered after only a few cleaning routines.
[0006] U.S. Patent Application 2006/0107704 to Passiniemi describes a steam distribution apparatus that is partitioned into a number of discharge chambers and includes screen plates which are welded to the partitions to prevent the screen plates from twisting or flexing. While the apparatus includes sealable slots for access to the internal compartments for cleaning, the slots afford only limited access.
SUMMARY OF THE INVENTION
[0007] The present invention is based in part on the development of a removable drop-out steam profiling cartridge that can be incorporated as part of a steam distribution apparatus. The cartridge is preferably fastened to the apparatus by bolts that are readily accessible from the back side of the apparatus. On its front side, the cartridge defines a plurality of isolated steam profiling zones that are separated by spaced-apart partitions or baffle panels that essentially eliminate the spilling over of steam from one profiling zone to the next. The profiling zones are covered by steam profiling screens having perforations through which steam exits. The profiling screens are welded to the baffles which enhances the structural integrity of the drop-out steam profiling cartridge. No external clamps or other devices are employed that would otherwise disrupt the smooth, curved exterior surface of the profiling screens. The drop-out cartridge design provides a rigid structure for cleaning.
[0008] Accordingly, one aspect of the invention is directed to an apparatus to distribute steam onto a moving sheet, the apparatus having a leading edge and a trailing edge relative to the moving sheet, the apparatus including:
[0009] an elongated steam chamber which has a front wall that defines a recess region;
[0010] a plurality of conduits each having an inlet located in the elongated steam chamber and an outlet;
[0011] a removable cartridge that is positioned in the recess region wherein the cartridge defines a plurality of compartments each of which is in communication with an outlet and wherein the cartridge has a front screen having a plurality of apertures through which steam can exit;
[0012] means for regulating the flow of steam through the inlet and outlet of each conduit; and
[0013] means for securing the removable cartridge to the recess region.
[0014] In another aspect, the invention is directed to an apparatus to distribute steam onto a continuously moving sheet that has an exterior contour wherein the apparatus has a leading edge and a trailing edge relative to the moving sheet, the apparatus including:
[0015] an elongated steambox header which has a front surface facing the moving sheet that defines a recess region;
[0016] a plurality of conduits each having an inlet located in the elongated steambox header and an outlet;
[0017] one or more removable cartridges that are juxtaposed along the length of the recess region wherein each cartridge comprises a frame that is partitioned along its length to form a plurality of profiling zones each of which is in communication with an outlet and wherein the frame has a front screen having apertures through which steam can exit and the screen defines an outer profiling surface with a contour conforming to the exterior contour of the moving sheet and which is flush with an exterior surface of the front surface of the elongated steambox header;
[0018] means for dependently regulating the flow of steam through the inlet and outlet of each conduit; and
[0019] means for fastening each removable cartridge to the elongated steambox header characterized in that each cartridge can be unfastened from a back side of the steambox header.
[0020] In a further aspect, the invention is directed to a method of distributing steam onto a continuously moving sheet which includes the steps of:
[0021] (a) positioning an apparatus having a leading edge and a trailing edge relative to the moving sheet, wherein the apparatus comprises:
(i) an elongated steam chamber that is in communication with a source of steam and which has a front wall that defines a recess region; (ii) a plurality of conduits each having an inlet located in the elongated steam chamber and an outlet; (iii) a removable cartridge that is positioned in the recess region wherein the cartridge defines a plurality of compartments each of which is in communication with an outlet and wherein the cartridge has a front screen having a plurality of apertures through which steam can exit; (iv) actuators for regulating the flow of steam through the inlet and outlet of each conduit; and (v) means for securing the removable cartridge to the recess region; and
[0027] (b) activating the actuators to allow steam through the conduits thereby delivering steam onto the moving sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1A is a cross sectional side view of a partially exposed portion of the steam distributor apparatus as steam is applied onto the surface of a moving sheet of paper that is supported on a roller;
[0029] FIG. 1B is a cross sectional side view of a partially exposed portion of the steam distributor apparatus showing the drop-out steam profiling cartridge removed;
[0030] FIG. 2 is a cross sectional side view of a partially exposed portion of the steam distributor apparatus showing an actuator; and
[0031] FIG. 3 is front view of the steam distribution apparatus illustrating the profiling compartments or zones and the positions of the cartridge bolts and steam discharge conduits.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] FIG. 1A illustrates a steam distributor apparatus 10 that is particularly suited for applying steam to a paper web or calendar roll in a sheet making process. Papermaking devices are well known in the art and are described, for example, in U.S. Pat. No. 5,539,634 to He and U.S. Pat. No. 5,022,966 to Hu, U.S. Pat. No. 4,982,334 to Balakrishnan, U.S. Pat. No. 4,786,817 to Boissevain et al., and U.S. Pat. No. 4,767,935 to Anderson et al. which are incorporated herein by reference.
[0033] Apparatus 10 includes housing or steambox 2 that encloses a main steam distribution header 32 which runs the length of the apparatus and which is connected to at least one source of steam (not shown). Steam distribution header 32 includes an interior wall 6 and an exterior wall 4 which defines an exterior recess region into which is a drop-out steam profiling cartridge 42 is inserted and attached. A pair of pipes 12 , 22 is welded onto interior wall 6 and exterior wall 4 ; each pipe is configured to provide a conduit or passageway through which a cartridge bolt can be inserted to fasten drop-out cartridge 42 . Specifically, cartridge bolts 14 , 24 are inserted through pipes 12 , 22 , respectively, and cartridge 42 includes two corresponding threaded mating nuts 18 , 28 , that are welded thereto, and that receive the distal ends of cartridge bolts 14 , 24 , respectively. Cartridge 42 is fastened by tightening cartridges bolts 14 , 24 whose proximal ends 16 , 26 are readily accessible through an inner enclosure 56 located at the back of steam distribution apparatus 10 . By removing wing-nuts 64 , 68 , cover 62 can be removed from flange 60 to expose enclosure 56 .
[0034] Steam exiting an opening 52 of valve sleeve 58 expands into the compartment or profiling zone 40 within cartridge 42 before being discharged through perforations in a profiling screen 38 and onto paper sheet 50 which is transported on a continuously rotating roll, for example. In this fashion, there is uniform steam distribution from a leading edge 51 to a trailing edge 53 of contoured profiling screen 38 as the sheet of material moves across profiling zone 40 in the machine direction. Condensate that forms on the bottom of profiling zone 40 seeps through a drain hole 54 and out through a condensate drain. The steam distributor apparatus is also equipped with a pressure gauge 34 and a main header condensate drain 36 .
[0035] The exterior or front surface of profiling screen 38 is preferably contoured to match the shape of paper sheet 50 . In this case, the concave-shaped curvature of profiling screen 38 is particularly suited for applying steam to a roll of material. The gap or distance between profiling screen 38 and paper sheet 50 typically ranges from 10 mm to 20 mm. The exterior surface of profiling screen 38 is flush with the outer, front surface of housing 2 . At the perimeter where the edges of cartridge 42 meet the edge of the recess region, silicone fillers are not needed to create a smooth continuous surface.
[0036] FIG. 1B shows the steam distribution apparatus with cartridge 42 removed from recess region 8 that is configured within exterior wall 4 . This can be readily accomplished by loosening cartridge bolts 14 , 24 to disengage the bolts from threaded nuts 18 , 28 , respectively. Cartridge 42 is preferably configured as a U-Shaped frame 30 that is covered by profiling screen 38 that has perforations or apertures that are sized and distributed to allow steam to discharge through in a predetermined pattern. Steam distributor apparatus 10 also includes a plurality of actuators each of which regulates the amount of steam which is discharged through an opening 52 of valve sleeve 58 . The use of cartridge bolts 14 , 24 to secure drop-out cartridge 42 and to maneuver profiling screen 38 into U-Shaped frame 30 permits design and manufacturing tolerances to be flexible without sacrificing performance of the steam distributor apparatus. The manufacturing process can be more readily streamlined.
[0037] As shown in FIG. 2 , high pressure steam that is supplied to main steam distribution header 32 is drawn into valve sleeve 58 through an annular opening 55 that is located between the valve sleeve 58 and pipe 74 . The amount of steam drawn is controlled by actuator 70 which is connected via connector 72 to a pneumatic supply which tunes or regulates the actuator by pressurizing a diaphragm that is on top of a piston that is located inside actuator 70 . The piston is connected to a measuring plug that moves inside pipe 74 to control the amount of steam that goes into a profiling zone 40 within cartridge 42 . Pneumatic actuators for regulating steam flow in a steam distribution apparatus are described, for instance, in U.S. Pat. Nos. 4,398,355 to Dove and 4,351,700 to Dove, which are incorporated herein by reference.
[0038] By monitoring and controlling the steam flow into each of a plurality of profiling zones 40 , a predetermined steam profile can be injected onto a sheet along its cross direction. The steam profile, as measured along the length of the steam distribution apparatus, can be uniform or non-uniform so that the sheet or web of material can be exposed to a steam curtain having different amounts of steam in the cross direction.
[0039] FIG. 3 illustrates a front view of steam distributor apparatus 10 exposing the compartment of the drop-out steam profiling cartridges without the profiling screens. Housing 2 , which is flanked by endplates 90 , 92 , forms an elongated structure having a front wall configured to serve as a recess region into which one or more drop-out steam profiling cartridges are secured. An external source of steam is connected through steam line 94 to steam distribution apparatus 10 and excess steam in the form of condensate exits through drain 96 .
[0040] As illustrated, a plurality of steam profiling zones or compartments spans the length of steam distributor apparatus 10 . Steam is supplied to each compartment via an opening 86 of a valve sleeve. The compartments are isolated from one another by zone dividers or baffles 102 , 104 which are spaced apart laterally and to which a stream profiling screen 38 ( FIG. 1B ) is welded. Baffles 102 , 104 also serve as internal gussets onto which U-Shaped frame 30 ( FIG. 1B ) of the drop-out steam profiling cartridge 42 ( FIG. 1B ) is welded. In this fashion, the steam profiling screen is held in place so as not to flex or expand outwardly and possibility come into contact with the paper sheet should the pressure in the compartment increase suddenly. In addition, the baffles prevent the spill-over of steam between steam profiling zones which minimizes the overall response width in the process of monitoring and controlling the steam profile. Since the steam profiling screen is welded to the cartridge, the screen can withstand a higher pressure from the steam jet at the actuator outlet than with conventional designs. For example, steam jet 52 may be allowed to impact steam profiling 38 screen directly without the need for a protective plate as illustrated in FIGS. 1A and 1B . As a result, a higher range of pressure distribution within the profiling zones or compartments can be achieved.
[0041] The structural integrity of the drop-out cartridge allows for optimal machine-direction placement of the perforations in profiling screen 38 ( FIG. 1B ). In particularly, unlike prior designs where the perforations are restricted primarily to the leading or trailing edges of the steambox, with the drop-out steam profiling cartridge, the screen holes can be moved to the center of the contoured surface. This feature may be beneficial in reducing the cross-directional response width (fanning out) of the process.
[0042] As described above, cartridge bolts are positioned along the length of the apparatus to secure the drop-out steam profiling cartridge. As shown in FIG. 3 , the bolts are connected to nuts, such as nuts 84 A and 84 B located in compartment 82 A. As depicted, pairs of bolts are spaced apart along the length of the apparatus; however, in order to fasten a cartridge to steam distributor apparatus 10 , it is not necessary that a pair of bolts be associated with each compartment.
[0043] The recess region is designed to accommodate one or more drop-out steam profiling cartridges. In the case where a single integral cartridge is employed, its length would essentially match that of the recess region. Alternatively, a plurality of shorter cartridges, which are individually inserted into the recess region and secured thereto, can be employed. The use of multiple smaller cartridges allows for selective removal for maintenance. For example, a sectioned cartridge that includes 9 steam profiling zones 82 A through 82 I is positioned in the recess region adjacent endplate 90 . Other sectional cartridges are then positioned in the recess region to form a series of sectional cartridges juxtaposed from end to end.
[0044] One benefit of employing sectional cartridges is that a fixed design unit can be more readily based-lined with conventional 3-D modeling and parameterized computer-aided design (CAD) software. Furthermore, once a design unit is dimensionally fixed, it can be used in the design of various steam distribution apparatuses. Finally, employing a drop-out steam profiling cartridge simplifies the overall design of the accompanying steambox header by reducing the number of internal channels. In particular, with comparable prior art steambox headers that accommodate removable steam profiling screens, a higher number of internal channels must be welded to the steambox headers in order to allow the removable screens to be positioned properly while maintaining the required contour of the steambox front side.
[0045] The length of steam distribution apparatus 10 typically corresponds to the width of the sheet or web to which steam is to be applied. For papermaking, the length generally ranges from 5 to 12 meters and typically is about 9 meters. Each steam profiling zone, e.g., 82 A in FIG. 3 , has a width of about 3 in. (7.6 cm) to 4 in. (10.2 cm). A typical steam distribution apparatus has up to about 90 steam profiling zones in total. In operation, the steam pressure in each profiling zone ranges up to about 80 kPa.
[0046] The foregoing has described the principles, preferred embodiments and modes of operation of the present invention. However, the invention should not be construed as being limited to the particular embodiments discussed. Thus, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of the present invention as defined by the following claims.
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A steam distributor for applying steam to a continuously moving paper sheet employs one or more drop-out steam profiling cartridges. Each cartridge is connected to a steam distribution apparatus and includes a number of profiling zones that are covered by a contoured, smooth profiling screen from which steam is applied. The profiling screens are welded to baffles which enhances the structural integrity of the cartridge. No external clamps or other devices are employed that would otherwise disrupt the smooth, curved exterior surface of the profiling screens. The spaced-apart baffles also eliminate the spilling over of steam from one profiling zone to the next which has the effect of minimizing the response width for steam profiling control. The use of the drop-out cartridges permits quick and easy removal of the profiling screens for change-out or cleaning.
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RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 11/424,664, filed on Jun. 16, 2006, now U.S. Pat. No. 7,277,062, entitled “MULTI-RESONANT MICROSTRIP DIPOLE ANTENNA”, which is related to U.S. patent application Ser. No. 11/424,614, filed on Jun. 16, 2006, entitled “MULTI-BAND ANTENNA” and U.S. patent application Ser. No. 11/424,639, filed on Jun. 16, 2006, entitled “MULTI-BAND RF COMBINER”. The above-noted applications are incorporated herein by reference.
BACKGROUND
Wireless telephones and other wireless devices have become almost the defacto standard for personal and business communications. This has increased the competition between wireless service providers to gain the largest possible market share. As the marketplace becomes saturated, the competition will become even tougher as the competitors fight to attract customers from other wireless service providers.
As part of the competition, it is necessary for each wireless service provider to stay abreast of technological innovations and offer their consumers the latest technology. However, not all consumers are prepared to switch their wireless devices as rapidly as technological innovations might dictate. The reasons for this are varied and may range from issues related to cost to an unwillingness to learn how to use a new device or satisfaction with their existing device.
However, certain technological innovations may require different antenna technologies in order to deliver service to the wireless customer. For example, although Wide Band Code Division Multiple Access (WCDMA) and Global System for Mobile communications (GSM) technologies typically operate on different frequencies, and they may require separate antennas, a wireless provider may have customers using both types of technologies. In many areas, simply leasing or buying new antenna space for the new technology may be economical. However, in many areas, particularly in urban areas, the cost of obtaining additional leases as well as zoning and other regulatory issues can make retaining old technologies while introducing new technologies cost prohibitive.
Thus, it is desirable to have an antenna capable of simultaneously radiating and receiving signals from both technologies (i.e., a multi-band antenna). One attempted solution is the Kathrein brand multi-band omni antenna which was developed for E911 Enhanced Observed Time Difference (EOTD) deployments to measure adjacent cell sites downlink messaging for determining a mobile location. However, the Kathrein brand antenna design has limited RF performance due to its unique antenna element design which limits gain to unity.
SUMMARY
The following presents a simplified summary of the subject matter in order to provide a basic understanding of some aspects of subject matter embodiments. This summary is not an extensive overview of the subject matter. It is not intended to identify key/critical elements of the embodiments or to delineate the scope of the subject matter. Its sole purpose is to present some concepts of the subject matter in a simplified form as a prelude to the more detailed description that is presented later.
The subject matter provides a multi-band antenna for use, for example, in a wireless communications network. The multi-band antenna employs multi-resonant microstrip dipoles that resonate at multiple frequencies due to microstrip “islands.” Gaps in the microstrips create an open RF circuit except for desired frequencies. At the desired frequency, RF energy sees a gap as a short circuit between an island and the rest of a dipole antenna, thus, resonating at the desired frequency. In one instance, the multi-band antenna includes first, second, third, and fourth dipole elements. The first dipole element is on a first side of a dielectric and the second dipole element is on a second side of the dielectric and oriented with respect to the first dipole element so as to form a first dipole. The third dipole element is also on the first side of the dielectric and is linearly displaced from the first dipole element in a direction parallel to the orientation of the first dipole wherein the displacement creates a gap between the first dipole element and the third dipole element. The fourth dipole element is on the second side of the dielectric linearly and is displaced from the second dipole element in a direction parallel to the orientation of the first dipole and opposite of the direction of displacement of the third dipole element from the first dipole element wherein the displacement creates a gap between the second dipole element and the fourth dipole element. The gaps between the first and third dipole elements and the second and fourth dipole elements are sufficiently small that the first, second, third, and fourth dipole elements form a second dipole having a corresponding dipole wavelength longer than that of the first dipole.
To the accomplishment of the foregoing and related ends, certain illustrative aspects of embodiments are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles of the subject matter may be employed, and the subject matter is intended to include all such aspects and their equivalents. Other advantages and novel features of the subject matter may become apparent from the following detailed description when considered in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a multi-band antenna system in accordance with an aspect of an embodiment.
FIG. 2 depicts a side view of a multi-band antenna in accordance with an aspect of an embodiment.
FIGS. 3A and 3B depict the two sides of the multi-band antenna in accordance with an aspect of an embodiment.
FIG. 4 depicts a side view of the multi-band antenna oriented ninety degrees away from the view depicted in FIG. 2 in accordance with an aspect of an embodiment.
FIG. 5 depicts a diagram illustrating a multi-band antenna encased in a radome in accordance with an aspect of an embodiment.
FIG. 6 depicts radiation patterns of a multi-band antenna with and without a parasitic element in accordance with an aspect of an embodiment.
FIG. 7 depicts a system diagram illustrating a communication system in accordance with an aspect of an embodiment.
DETAILED DESCRIPTION
The subject matter is now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the subject matter. It may be evident, however, that subject matter embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the embodiments.
In FIG. 1 , a block diagram of a multi-band antenna system 100 in accordance with an aspect of an embodiment is shown. The multi-band antenna system 100 is comprised of a multi-band antenna 102 that can transmit and/or receive different wavelengths, λ, from a shorter λ frequency transceiver 104 and from a longer λ frequency transceiver 106 . Dipole elements of the multi-band antenna 102 employ “gaps” in the dipole elements that tune the dipole elements to see more than one desired wavelength (i.e., frequency). Wavelengths, with sufficient length, “jump” the gap and resonate the dipole element at the longer wavelength. In this manner, the dipole element acts like a multi-band dipole element. Thus, a single multi-band antenna 102 can replace multiple antennas that can only operate at a given frequency and/or can increase communication frequency bands when antenna installation space is limited. This provides a very cost effective and space effective alternative to multiple antenna installations.
Turning to FIG. 2 , a side view of a multi-band antenna 200 in accordance with an aspect of an embodiment is depicted. The multi-band antenna 200 can be employed as, for example, one of the plurality of towers 730 depicted in FIG. 7 . The multi-band antenna 200 is a microstrip multi-band collinear array with dipole elements 201 - 204 and 211 - 214 arranged on both sides of serial feedlines 250 and 252 and both sides of a dielectric material 260 . The dielectric material 260 can be any RF dielectric such as, for example, a PTFE (polytetrafluoroethylene)/fiberglass composite. The elements 201 , 203 , 211 , 213 , and 250 on a first side of the multi-band antenna 200 are illustrated with solid lines and the elements 202 , 204 , 212 , 214 , and 252 on the second side of the multi-band antenna separated from the first side by the dielectric material 260 are represented by dashed lines in FIG. 2 .
Serial feedlines (also referred to as microstrips) 250 and 252 and dipole elements 201 - 204 and 211 - 214 are constructed from a metal such as, for example, copper and the like. A pattern is etched and/or otherwise formed into each side of the dielectric material 260 corresponding to the locations of the serial feedlines 250 and 252 and the dipole elements 201 - 204 and 211 - 214 on that side of the dielectric material 260 . Metal is then deposited into the pattern to form the feedlines 250 and 252 and the dipole elements 201 - 204 and 211 - 214 . In the alternative, a metal sheet, such as, for example, copper, is attached and/or deposited on each side of the dielectric. The dipole element and feedline pattern is then formed by printing an acid resistant mask onto the metal and using an acid bath to remove the unpatterned metal.
The impedance of the feedlines 250 and 252 should approximately match the impedance of a transmission line carrying RF signals from a transmitter and/or to a receiver. For a coaxial transmission line, this impedance is typically around 50 ohms. The impedance of the dipole elements 201 - 204 and 211 - 214 should be approximately that of free space (i.e., approximately 377 ohms).
Dipole element 201 and dipole element 202 on the opposite side of dielectric material 260 form a dipole for a given first wavelength of radiation/reception. Similarly, dipole element 203 and 204 also form a dipole for the same wavelength of radiation/reception since the dipole formed by dipole elements 203 and 204 has an approximately equivalent length to the dipole formed by dipole elements 201 and 202 . A gap 221 - 224 exists between dipole elements 201 - 204 and their corresponding dipole elements 211 - 214 . For shorter wavelengths, the gaps 221 - 224 form an open circuit between dipole elements 201 - 204 and dipole elements 211 - 214 . However, for longer wavelengths, if the gaps 221 - 224 are chosen correctly, the gaps 221 - 224 are effectively short circuited so that a longer dipole equal in length, for example, to the combined lengths of dipole elements 201 - 202 , dipole elements 211 - 212 , and gaps 221 and 223 . Thus, dipole elements 201 - 202 and 211 - 212 form a dipole for a second wavelength of radiation longer than that of the first wavelength dipole. Therefore, the multi-band antenna 200 functions on two bands (i.e., two different wavelengths). The multi-band antenna 200 can also have a cylindrical radome (not shown) placed over the antenna structure for weather proofing. The multi-band antenna 200 is presented as an example of a multi-band antenna and is not meant to imply any architectural limitations.
With reference to FIGS. 3A-3B , the two sides of the multi-band antenna 200 are depicted in accordance with an aspect of an embodiment. FIG. 3A depicts side 1 on the multi-band antenna 200 . FIG. 3B depicts side 2 of the multi-band antenna 200 . Both the views in FIG. 3A and FIG. 3B are from the same side, but represent a different cross-section of the multi-band antenna 200 . In between the two cross-sections shown in FIG. 3A and FIG. 3B is a layer of dielectric material 260 . The pattern of the microstrips (serial feedlines) 250 and 252 , and the dipole elements 201 - 204 and 211 - 214 , as described above, is etched and/or otherwise formed (for example, by utilizing a reversed mask process) in a dielectric material 260 and an electrically conductive material such as, for example, copper is deposited onto each side of the dielectric material 260 to form the multi-band antenna 200 .
Moving on to FIG. 4 , a side view of the multi-band antenna 200 oriented ninety degrees away from the view depicted in FIG. 2 is shown in accordance with an aspect of an embodiment. In this view, it is apparent that microstrip (serial feedlines) elements 250 and 252 as well as associated dipole elements connected to microstrip (serial feedlines) elements 250 and 252 are separated from each other by dielectric material 260 .
Turning to FIG. 5 , a diagram illustrating a multi-band antenna 504 encased in a radome 506 is depicted in accordance with an aspect of an embodiment. The multi-band antenna 504 tranceives multiple frequency bands similar to, for example, multi-band antenna 200 in FIG. 2 and is encased within the radome 506 which has a parasitic element 502 attached to the outside. Without the parasitic element 502 , the radiation pattern of the multi-band antenna 504 is elliptical as illustrated in a radiation pattern 604 shown in FIG. 6 . However, with the addition of parasitic element 502 , the radiation pattern produced by the multi-band antenna 504 becomes substantially circular and omni directional as depicted by radiation pattern 602 in FIG. 6 .
The antennas depicted in FIGS. 2-4 are examples of multi-band antennas with dual bands. Dual-band antennas have been shown for simplicity of explanation. However, these antennas are presented and intended only as examples of a multi-band antenna and not as architectural limitations. It is appreciated that the instances presented above can be extended to antennas having three, four, or more operation bands by adding gaps and additional dipole elements of lengths appropriate to add a longer dipole to the existing dipoles corresponding to the additional bands desired. Additional multi-band dipole elements can be added to improve gain.
In order to provide additional context for implementing various aspects of the embodiments, FIG. 7 and the following discussion are intended to provide a brief, general description of a suitable communication network 700 in which the various aspects of the embodiments can be performed. It can be appreciated that the inventive structures and techniques can be practiced with other system configurations as well.
In FIG. 7 , a system diagram illustrating a communications network 700 in accordance with an aspect of an embodiment is depicted. The communications network 700 is a plurality of interconnected heterogeneous networks in which instances provided herein can be implemented. As illustrated, communications network 700 contains an Internet Protocol (IP) network 702 , a Local Area Network (LAN)/Wide Area Network (WAN) 704 , a Public Switched Telephone Network (PSTN) 709 , cellular wireless networks 712 and 713 , and a satellite communication network 716 . Networks 702 , 704 , 709 , 712 , 713 and 716 can include permanent connections, such as wire or fiber optic cables, and/or temporary connections made through telephone connections. Wireless connections are also viable communication means between networks.
IP network 702 can be a publicly available IP network (e.g., the Internet), a private IP network (e.g., intranet), or a combination of public and private IP networks. IP network 702 typically operates according to the Internet Protocol (IP) and routes packets among its many switches and through its many transmission paths. IP networks are generally expandable, fairly easy to use, and heavily supported. Coupled to IP network 702 is a Domain Name Server (DNS) 708 to which queries can be sent, such queries each requesting an IP address based upon a Uniform Resource Locator (URL). IP network 702 can support 32 bit IP addresses as well as 128 bit IP addresses and the like.
LAN/WAN 704 couples to IP network 702 via a proxy server 706 (or another connection). LAN/WAN 704 can operate according to various communication protocols, such as the Internet Protocol, Asynchronous Transfer Mode (ATM) protocol, or other packet switched protocols. Proxy server 706 serves to route data between IP network 702 and LAN/WAN 704 . A firewall that precludes unwanted communications from entering LAN/WAN 704 can also be located at the location of proxy server 706 .
Computer 720 couples to LAN/WAN 704 and supports communications with LAN/WAN 704 . Computer 720 can employ the LAN/WAN 704 and proxy server 706 to communicate with other devices across IP network 702 . Such communications are generally known in the art and are described further herein. Also shown, phone 722 couples to computer 720 and can be employed to initiate IP telephony communications with another phone and/or voice terminal using IP telephony. An IP phone 754 connected to IP network 702 (and/or other phone, e.g., phone 724 ) can communicate with phone 722 using IP telephony.
PSTN 709 is a circuit switched network that is primarily employed for voice communications, such as those enabled by a standard phone 724 . However, PSTN 709 also supports the transmission of data. PSTN 709 can be connected to IP Network 702 via gateway 710 . Data transmissions can be supported to a tone based terminal, such as a FAX machine 725 , to a tone based modem contained in computer 726 , or to another device that couples to PSTN 709 via a digital connection, such as an Integrated Services Digital Network (ISDN) line, an Asynchronous Digital Subscriber Line (ADSL), IEEE 802.16 broadband local loop, and/or another digital connection to a terminal that supports such a connection and the like. As illustrated, a voice terminal, such as phone 728 , can couple to PSTN 709 via computer 726 rather than being supported directly by PSTN 709 , as is the case with phone 724 . Thus, computer 726 can support IP telephony with voice terminal 728 , for example.
Cellular networks 712 and 713 support wireless communications with terminals operating in their service area (which can cover a city, county, state, country, etc.). Each of cellular networks 712 and 713 can operate according to a different operating standard utilizing a different frequency (e.g., 850 and 1900 MHz) as discussed in more detail below. Cellular networks 712 and 713 can include a plurality of towers, e.g., 730 , that each provide wireless communications within a respective cell. At least some of the plurality of towers 730 can include a multi-band antenna allowing a single antenna to service both networks' 712 and 713 client devices. Wireless terminals that can operate in conjunction with cellular network 712 or 713 include wireless handsets 732 and 733 and wirelessly enabled laptop computers 734 , for example. Wireless handsets 732 and 733 can be, for example, personal digital assistants, wireless or cellular telephones, and/or two-way pagers and operate using different wireless standards. For example, wireless handset 732 can operate via a TDMA/GSM standard and communicate with cellular network 712 while wireless handset 733 can operate via a UMTS standard and communicate with cellular network 713 Cellular networks 712 and 713 couple to IP network 702 via gateways 714 and 715 respectively.
Wireless handsets 732 and 733 and wirelessly enabled laptop computers 734 can also communicate with cellular network 712 and/or cellular network 713 using a wireless application protocol (WAP). WAP is an open, global specification that allows mobile users with wireless devices, such as, for example, mobile phones, pagers, two-way radios, smart phones, communicators, personal digital assistants, and portable laptop computers and the like, to easily access and interact with information and services almost instantly. WAP is a communications protocol and application environment and can be built on any operating system including, for example, Palm OS, EPOC, Windows CE, FLEXOS, OS/9, and JavaOS. WAP provides interoperability even between different device families.
WAP is the wireless equivalent of Hypertext Transfer Protocol (HTTP) and Hypertext Markup Language (HTML). The HTTP-like component defines the communication protocol between the handheld device and a server or gateway. This component addresses characteristics that are unique to wireless devices, such as data rate and round-trip response time. The HTML-like component, commonly known as Wireless Markup Language (WML), defines new markup and scripting languages for displaying information to and interacting with the user. This component is highly focused on the limited display size and limited input devices available on small, handheld devices.
Each of Cellular network 712 and 713 operates according to an operating standard, which can be different from each other, and which may be, for example, an analog standard (e.g., the Advanced Mobile Phone System (AMPS) standard), a code division standard (e.g., the Code Division Multiple Access (CDMA) standard), a time division standard (e.g., the Time Division Multiple Access (TDMA) standard), a frequency division standard (e.g., the Global System for Mobile Communications (GSM)), or any other appropriate wireless communication method. Independent of the standard(s) supported by cellular network 712 , cellular network 712 supports voice and data communications with terminal units, e.g., 732 , 733 , and 734 . For clarity of explanation, cellular network 712 and 713 have been shown and discussed as completely separate entities. However, in practice, they often share resources.
Satellite network 716 includes at least one satellite dish 736 that operates in conjunction with a satellite 738 to provide satellite communications with a plurality of terminals, e.g., laptop computer 742 and satellite handset 740 . Satellite handset 740 could also be a two-way pager. Satellite network 716 can be serviced by one or more geosynchronous orbiting satellites, a plurality of medium earth orbit satellites, or a plurality of low earth orbit satellites. Satellite network 716 services voice and data communications and couples to IP network 702 via gateway 718 .
FIG. 7 is intended as an example and not as an architectural limitation for instances disclosed herein. For example, communication network 700 can include additional servers, clients, and other devices not shown. Other interconnections are also possible. For example, if devices 732 , 733 , and 734 were GPS-enabled, they could interact with satellite 738 either directly or via cellular networks 712 and 713 .
What has been described above includes examples of the embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of the embodiments are possible. Accordingly, the subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
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A multi-band antenna for use, for example, in a wireless communications network, employs multi-resonant microstrip dipoles that resonate at multiple frequencies due to microstrip “islands.” Gaps in the microstrips create an open RF circuit except for desired frequencies. At a desired frequency, RF energy sees a gap as a short circuit between an island and the rest of a dipole antenna, thus, resonating at the desired frequency. In one instance, the multi-band antenna includes a first, second, third, and fourth dipole elements. Gaps between the first and third dipole elements and the second and fourth dipole elements are sufficiently small that the first, second, third, and fourth dipole elements form a second dipole having a corresponding dipole wavelength longer than that of the first dipole.
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CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims priority under 35 U.S.C. §119 to New Zealand Patent Application No. 607685, filed Feb. 28, 2013, the entire contents of which are incorporated herein by reference.
STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
FIELD OF THE DISCLOSURE
[0003] The present disclosure relates to a system, device, and method for processing a length of material. In particular this disclosure relates to a method and apparatus for processing a portion of wood such as a stem, log, or other piece of wood.
BACKGROUND OF THE DISCLOSURE
[0004] The modern forestry industry is continually seeking to improve efficiency in processing timber. It is well-known to mount a timber-working device to a carrier vehicle in order to perform a number of operations in connection with timber processing. These operations may include one, or a combination of, grappling and felling a standing tree, delimbing a felled stem, debarking the stem, and cutting the stem into logs. Devices commonly known as harvester heads typically have the capability to perform all of these functions.
[0005] Many such harvester heads have the ability to measure the diameter and length of a log and automatically determine the optimal position of saw cuts in order to maximize the value of that log. Previously, an operator may have been required to calculate optimal value manually, or manually control the harvester head to perform cutting at points previously measured and marked. Automation of this process would be expected to improve productivity. However, elements of the process still currently require decision making on the part of the operator.
[0006] In particular, harvester heads commonly include two chainsaws—one at each end of the head. One of these chainsaws is typically designated as the “main” saw, having greater cutting capabilities in terms of stem diameter. The other chainsaw is usually used only for “topping” the stem—removing the undesirable end of the stem which is below a certain diameter—and as such the “top” saw generally has lower cutting capabilities than the main saw.
[0007] During typical operation of a harvester head—especially the processing of heavy limbed trees—a felled stem will be delimbed by feeding the stem through delimbing knives while logging the length and diameter of the stem. A cutting solution will then be determined based on the measured parameters.
[0008] Delimbing is generally performed from the largest diameter end of the stem—known as the Large End Diameter (LED)—in order to ensure that the harvester head may maintain a grip on the stem and allow the more valuable part of the stem to be processed. As such, the cutting solution is generally determined after the harvester head has arrived at the Small End Diameter (SED) of the stem.
[0009] Once a cutting solution has been determined the stem is usually reversed to the end of the stem with the LED, in order than the stem may be driven to the next cutting position, and the main saw used to cut the log. Following this method eliminates the need for the operator to make a decision regarding selection of the appropriate saw to make the first cut—reducing operator fatigue and maintaining operating efficiency. The process is continued to the last log length of the cutting solution, where the top saw is used to make the final cut.
[0010] This has several problems associated with it. In particular, the method requires the harvester to travel along the length of the stem three times—once for delimbing and measurement of the stem, once to return to the LED, and once to carry out the cutting solution. This adds to the fuel requirements of operating the head, and adds to the processing time—reducing the cost effectiveness of the harvester.
[0011] Further, it is generally desirable to reduce the number of passes a harvester head needs to make along the stem in order to reduce the damage to the stem by the feed mechanism—particularly for softer or ornamental wood where the value may decrease with bruising.
[0012] In some setups, the operator can choose whether to use the main or top saw to cut the stem at each position to achieve the cutting solution. This requires the operator to assess whether the diameter of the stem at a particular position is greater than the cutting capacity of the top saw, or whether the stem should be driven to the LED in order to process the stem as described above. This step takes time and causes operator stress and fatigue, which may in turn lead to poor decision making with regard to control of the harvester head and lost value to the forest owner.
[0013] All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinence of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
[0014] Throughout this specification, the word “comprise” or “include”, or variations thereof such as “comprises”, “includes”, “comprising”, or “including” will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
[0015] Further aspects and advantages of the present disclosure will become apparent from the ensuing description which is given by way of example only.
SUMMARY OF THE DISCLOSURE
[0016] According to an exemplary embodiment of the disclosure there is provided an electronic control device for a material-working device including a first cutting device having a first cutting capacity, and a second cutting device having a second cutting capacity. The control device may comprise at least one processor. The at least one processor may be configured to receive data relating to the length of a length of material being processed by the material-working device and the diameter of the length of material at a plurality of points along its length. The at least one processor may further be configured to set at least one cutting position along the length of the length of material based on at least the length of the length of material. The at least one processor may further be configured to determine the diameter of the length of material at the cutting position using at least the data relating to the diameter of the length of material at the plurality of points along its length. The at least one processor may further be configured to select either the first cutting device or second cutting device for use in cutting the length of material at the cutting position based at least in part on the cutting capacity of each cutting device and the diameter of the length of material at the cutting position.
[0017] According to an exemplary embodiment of the disclosure there is provided a system for processing a length of material. The system may comprise a material-working device. The material-working device may comprise a first cutting device having a first cutting capacity, and a second cutting device having a second cutting capacity. The material-working device may also comprise a drive mechanism configured to drive the length of material relative to the material-working device, at least one distance measuring device, and at least one diameter measuring device. The system may comprise at least one processor. The at least one processor may be configured to receive data relating to the length of the length of material from the distance measuring device. The at least one processor may be configured to receive data relating to the diameter of the length of material at a plurality of points along its length from the diameter measuring device. The at least one processor may be configured to set at least one cutting position along the length of the length of material based on at least the length of the length of material. The at least one processor may be configured to determine the diameter of the length of material at the cutting position using at least the data relating to the diameter of the length of material at the plurality of points along its length. The at least one processor may be configured to select either the first cutting device or second cutting device for use in cutting the length of material at the cutting position based at least in part on the cutting capacity of each cutting device and the diameter of the length of material at the cutting position.
[0018] According to an exemplary embodiment of the present disclosure there is provided a method for processing a length of material using a material-working device comprising a first cutting device having a first cutting capacity, and a second cutting device having a second cutting capacity. The method may comprise receiving data relating to the length of the length of material and the diameter of the length of material at a plurality of points along its length. At least one cutting position may be set along the length of the length of material based on at least the data relating to the length of the length of material. The diameter of the length of material at the cutting position may be determined using at least the data relating to the diameter of the length of material at the plurality of points along its length. Either the first cutting device or second cutting device may be selected for use in cutting the length of material at the cutting position based at least in part on the cutting capacity of each cutting device and the diameter of the length of material at the cutting position.
[0019] According to another exemplary of the present disclosure there is provided an article of manufacture having computer storage medium storing computer readable program code executable by a computer to implement a method for operating a material-working device comprising a first cutting device having a first cutting capacity and a second cutting device having a second cutting capacity. The code may comprise computer readable program code receiving data relating to the length of the length of material and the diameter of the length of material at a plurality of points along its length. The code may comprise computer readable program code setting at least one cutting position along the length of the length of material based on at least the data relating to the length of the length of material. The code may comprise computer readable program code determining the diameter of the length of material at the cutting position using at least the data relating to the diameter of the length of material at the plurality of points along its length. The code may further comprise computer readable program code selecting either the first cutting device or second cutting device for use in cutting the length of material at the cutting position based at least in part on the cutting capacity of each cutting device and the diameter of the length of material at the cutting position.
[0020] In an exemplary embodiment the material-working device may be a timber-working device—in particular a harvester head, and may be referred to as such throughout the specification. Harvester heads typically have the capability to grapple and fell a standing tree, delimb and/or debark a felled stem, and cut the stem into logs. However, a person skilled in the art should appreciate that embodiments of the disclosure may be used with other timber-working devices having multiple cutting devices, for example a feller buncher, disc saw head, saw grapple, and so on—and that reference to the timber-working device being a harvester head is not intended to be limiting.
[0021] Also, reference will herein be made throughout the specification to the length of material as being the stem of a tree. It should be appreciated that while it is envisaged that embodiments of the disclosure may have particular application to the processing of a felled tree stem, this is not intended to be limiting. For example, embodiments of the disclosure may be used in the processing of other wood products—such as wood which has been sawn into boards—although embodiments of the disclosure may be applied to effectively any material where it is desirable to reduce the processing time in cutting the material into desired lengths.
[0022] In an exemplary embodiment, each cutting device may comprise at least one saw. It is envisaged that embodiments of the disclosure may have particular application to timber-working devices comprising chainsaws. Each chainsaw may comprise a saw chain, a saw bar around which the saw chain moves, and a saw drive gear for driving the saw chain around the saw bar. However, this is not intended to be limiting as the cutting device may take other forms—for example a disc saw, or shears.
[0023] Reference to cutting capacity should be understood to refer to the ability of a cutting device to cut the length of material being processed. In the context of a saw—particularly a chainsaw—cutting capacity may be influenced by the length or depth of material a saw is capable of cutting, and/or power rating. Generally, in the context of processing tree stems it may be desirable for a log to be cut using a single pass of the cutting device to ensure a clean cut and reduce processing time. As such, the diameter of the material being cut may be significant in determining whether the cutting capacity of a cutting device is sufficient to carry out a cut at a particular cutting position.
[0024] Harvester heads may comprise a main saw which is primarily used for the felling and cross cutting of stems. Further, some harvester heads may comprise a secondary or topping saw. The topping saw is typically of a lower specification than the main saw, and used primarily during processing once a tree is felled. The first cutting device and second cutting device may herein be referred to as the main saw and top saw respectively, although it should be appreciated that this is not intended to be limiting.
[0025] Harvester heads typically comprise a drive mechanism in the form of at least one driven roller—for example rollers mounted on grapple arms which grip the stem and control position of the stem relative to the saw or saws. The drive mechanism may allow the stem to be moved relative to the harvester head for debarking, delimbing, and sawing.
[0026] A distance measurement device may be incorporated into or associated with the drive mechanism, or a separate device. An example of a distance measurement device is a rotary encoded measuring wheel, which is rotated as a stem is driven relative to the harvester head. In the prior art, the encoder simply counts up or down depending on the direction in which it is being driven. It is envisaged that in embodiments of the disclosure the count may be based on the direction for processing of a cutting solution.
[0027] In an embodiment the harvester head may measure other characteristics of the stem. In embodiments, the harvester head may measure diameter of the stem. It is known to measure diameter using deflection of the delimbing knives, or drive arms. Other characteristics such as stiffness or strength may also be measured, for example as described in New Zealand Patent No. 545247 titled “Method and apparatus for assessing or predicting the characteristics of wood”, the contents of which are hereby incorporated by reference.
[0028] In an exemplary embodiment, setting the cutting position comprises the processor determining the cutting position along the length of the length of material using at least the data relating to the length of the length of material.
[0029] However, it is envisaged that in some embodiments the operator may have the option to manually determine the next cutting position based on the length measurement, and provide this as an input to the processor. While it may be generally desirable to automate such decision making, it may be advantageous to allow for the possibility of the operator using their experience to pre-empt or overrule automated solutions.
[0030] In an exemplary embodiment a plurality of cutting positions along the length of the length of material are determined. The plurality of cutting positions may be determined as part of a value optimization process for the stem. It is known in the art for timber processing systems to automatically determine the optimal position of saw cuts in order to maximize the value of a particular stem.
[0031] In addition to length, the value of a log may comprise factors such as diameter and grade. A value matrix typically uses these measured or observed variables together with market prices to determine the most valuable combination of logs which may be obtained from the stem. Optimization may also account for targeted length and diameters for a particular stand of trees, which meets the demands of the forest owner while perhaps not producing the highest dollar value combination based on market values.
[0032] It is envisaged that the cutting positions may be determined such that the end of the stem with the larger diameter is prioritized over the end with the lesser diameter. While this is not intended to be limiting, it is envisaged that in doing so wastage may be reduced.
[0033] It should be appreciated that determining the diameter of the stem at a cutting position may comprise approximating the diameter at that position based on measurements made on either side of the cutting position along the length of the stem. It is envisaged that diameter measurements may be made at intervals along the length of the stem (for example, every 100 millimeters approximately), and that deviation of diameter within these intervals is unlikely to be significant for the purpose of comparison with the cutting capacities of the cutting devices.
[0034] In some embodiments, the system may select the cutting device having the greater cutting capacity when the predicted diameter is within the cutting capability of the other cutting device, but also within a predetermined margin of error.
[0035] In an exemplary embodiment, the processor may be configured to determine the order in which the cutting positions are to be cut. Determining the order in which the cutting positions are to be cut may be based at least in part on distance the harvester head would be required to travel relative to the length of material—in particular the minimum travel required. In doing so it is envisaged that the time required to process a stem may be reduced, along with fuel consumption and operating stresses on the equipment. Damage to the stem may also be reduced, preserving its value. By automating this process, operator requirements may also be reduced—in turn reducing mental stress and associated fatigue.
[0036] It should be appreciated that determining the minimum distance may be influenced by other factors. For example, the minimum distance may be determined based on the requirement that the remaining length of the stem remains held by the harvester head—such that the operator does not need to pick up a length of stem which has been cut off in order to finish processing that length. Preferably, the cutting order is determined based in part on the requirement that the stem remain held by the harvester head until the final cutting position has been cut.
[0037] In an exemplary embodiment, if any of the cutting positions are beyond the cutting capacity of a cutting device, the other cutting device may be selected to cut the stem at all of the cutting positions.
[0038] The processor may be configured to control the harvester head to align the selected cutting device with the associated cutting position. When aligned at the cutting positioned, the system may require manual activation of the selected cutting device by the operator. In another embodiment the system may automatically control operation of the cutting device at the cutting position.
[0039] The various steps or acts in a method or process may be performed in the order shown, or may be performed in another order. Additionally, one or more process or method steps may be omitted or one or more process or method steps may be added to the methods and processes. An additional step, block, or action may be added in the beginning, end, or intervening existing elements of the methods and processes.
[0040] The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented by a programmed processor executing instructions stored in memory. The functions, acts or tasks are independent of the particular type of instructions set, storage media, processor or processing strategy and may be performed by software, hardware, integrated circuits, firm-ware, micro-code and the like, operating alone or in combination.
[0041] The memory may comprise computer-readable media. The term “computer-readable medium” may comprise a single medium or multiple media, such as a centralized or distributed database, and/or associated caches and servers that store one or more sets of instructions. The term “computer-readable medium” may also comprise any medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor or that cause a computer system to perform any one or more of the methods or operations disclosed herein. The “computer-readable medium” may be non-transitory, and may be tangible.
[0042] It should be appreciated that in exemplary embodiments one or more dedicated hardware implementations, such as application specific integrated circuits, programmable logic arrays and other hardware devices, can be constructed to implement one or more of the methods described herein. One or more embodiments described herein may implement functions using two or more specific interconnected hardware modules or devices with related control and data signals that can be communicated between and through the modules, or as portions of an application-specific integrated circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Embodiments of the present disclosure may be better understood with reference to the following description and accompanying drawings, which are given by way of example only:
[0044] FIG. 1A is a side view of an exemplary material-working system comprising an exemplary material-working device in the form of a forestry head;
[0045] FIG. 1B is an elevated view of the forestry head;
[0046] FIG. 2A is a diagrammatic view of an exemplary control system for the exemplary material-working system;
[0047] FIG. 2B illustrates an exemplary display device as part of the exemplary control system;
[0048] FIG. 3 is a flowchart illustrating an exemplary method for processing a length of material such as a tree stem using the exemplary system;
[0049] FIG. 4A illustrates a exemplary stem to be processed according to an exemplary method of the present disclosure, and
[0050] FIG. 4B illustrates a cutting solution for the stem according to an embodiment of the present disclosure.
DETAILED DESCRIPTION
[0051] FIG. 1A illustrates a timber-working system comprising a carrier 1 for use in forest harvesting. The carrier 1 comprises an operator cab 2 from which an operator (not shown) controls the carrier 1 . The carrier 1 further comprises a boom assembly 3 , to which a timber-working device in the form of a forestry head 4 is connected.
[0052] Connection of the head 4 to the boom assembly 3 comprises a rotator 5 , configured to rotate the head 4 about the generally vertical axis of rotation marked by dashed line 6 . A tilt bracket 7 further allows rotation of the head 4 between a prone position (as illustrated) and a standing position.
[0053] Referring to FIG. 1B , the head 4 comprises a frame 8 to which the tilt bracket 7 of FIG. 1 is pivotally attached. Right hand (RH) and left hand (LH) delimb arms 9 a and 9 b are pivotally attached to the frame 8 , as are opposing RH and LH feed arms 10 a and 10 b . RH and LH feed wheels 11 a and 11 b are attached to RH and LH drive arms 10 a and 10 b respectively, which together with a frame-mounted feed wheel 12 may be controlled to feed one or more stems (not illustrated) along feed axis 13 of the head 4 . Feed wheels 11 a , 11 b , 12 are driven by hydraulic motors, and may collectively be referred to as the ‘feed mechanism.’ The displacement of the delimbing arms 9 a or 9 b and/or feed arms 10 a or 10 b may be used to determine the diameter of the stem at that point.
[0054] A measuring wheel 14 may be used to measure the length of stems processed by the head 4 . The measuring wheel 14 may be selectively raised and lowered into contact with the stems as desired. Alternatively, rotation or runtime of the feed wheels 11 a or 11 b , may be used to measure the length of the stem as it is driven relative to the head 4 .
[0055] A main chainsaw 15 , and a topping chainsaw 16 , are attached to the frame 8 . The main saw 15 is typically used to fell a tree when the head 4 is in a harvesting position, and to buck stems into logs in the processing position of the head 4 (as seen in FIG. 1A ). The topping saw 16 may be used to cut off a small-diameter top portion of the stem(s) to maximize the value recovery of the trees. The main saw 15 has a greater cutting capacity in terms of the diameter of stem it is capable of sawing through than the topping saw 16 .
[0056] An optical sensor 17 is positioned at the end of the head 4 next to the main saw 15 . The optical sensor 17 may be used to locate an end of a stem as it is driven through the head 4 .
[0057] The various operations of the head 4 may be controlled by the operator using hand and foot controls as known in the art. Further, certain automated functions of the harvester head 4 may be controlled by an electronic control system 20 as shown by FIG. 2A and FIG. 2B .
[0058] The control system 20 comprises one or more electronic controllers, each controller comprising a processor and memory having stored therein instructions which, when executed by the processor, causes the processor to perform the various operations of the controller.
[0059] For example, the control system 20 comprises a first controller 21 on board the carrier 1 and a second controller 22 on board the head 4 . The controllers 21 and 22 are connected to one another via a communications bus 23 (e.g., a CAN bus).
[0060] A human operator operates an operator input device 24 , for example hand and foot controls, located at the operator's cab 2 of the carrier 1 to control the head 4 . Details of operation are output to an output device 25 —for example a display device. Certain automated functions may be controlled by first controller 21 and/or second controller 22 .
[0061] The head 4 has a number of valves 26 arranged, for example, in a valve block and coupled electrically to the second controller 22 so as to be under its control. The valves 26 comprise, for example, drive valves 27 configured to control operation of the motors associated with the RH and LH feed wheel 11 a and 11 b , and frame-mounted feed wheel 12 a.
[0062] The valves 26 further comprise delimb drive valves 28 for controlling operation of the delimb arms 9 a and 9 b , main saw drive valve 29 and topping saw drive valve 30 for controlling operation of the saws 15 and 16 respectively, and measuring wheel valves 31 for controlling the transfer of the measuring wheel 14 between its extended and retracted positions.
[0063] FIG. 2B illustrates an exemplary display device 25 on which details of the operations of the head 4 may be displayed. For example, information regarding the current log to be cut from the stem may be presented in the central area 32 . The next logs in the sequence may be displayed in a queuing area 33 . The currently selected saw may be displayed in an icon 34 .
[0064] Referring to FIG. 3 , the control system 20 is configured to implement exemplary method 300 , which will be described with reference to FIG. 1A , FIG. 1B , FIG. 2A , and FIG. 2B .
[0065] At step 301 , an end of the stem is found using the optical sensor 17 —preferably the Large End Diameter. The stem is delimbed by a human operator operating the input device 24 to cause the first controller 21 to broadcast a command on bus 23 to feed the stem, which is in turn received by the second controller 22 which outputs control signals to drive valves 27 causing the wheels 11 a , 11 b , and 12 to feed the stem in the desired direction through the delimb arms 9 a and 9 b.
[0066] In step 302 , while the stem is being fed through, the second controller 22 receives signals from the distance measuring wheel 14 indicating the distance travelled. Diameter measurements are also taken at 100 millimeter intervals using deflection of the delimb arms 9 a or 9 b and/or feed arms 10 a or 10 b . These measurements are transmitted to the first controller 21 over the bus 23 .
[0067] At step 303 the other end of the stem is identified—whether through determination that a minimum diameter has been reached, or on manual designation by the operator via input device 24 .
[0068] In step 304 , the first controller 21 uses the measured length and diameters to determine at least one cutting position along the length of the stem such that the value of the resulting logs is optimized.
[0069] These are displayed to the operator on display device 25 in step 305 , who can choose to make changes in step 306 —for example changing the grade of the stem. Those changes may require re-optimization of the cutting solution by the first controller 21 .
[0070] If the operator approves the cutting solution, then the first controller 21 determines the diameter of the stem at the cutting positions at step 307 .
[0071] At step 308 the first controller 21 then determines the order in which the cutting positions are to be cut based on the minimum distance the head 4 will be required to travel relative to the stem while maintaining control of the stem using the feed rollers 11 a , 11 b , and 12 . This comprises selecting either the main saw 15 or top saw 16 to make each cut based on the cutting capacity of the saws and the diameter of the stem at each cutting position.
[0072] At step 309 the first controller 21 broadcasts control signals for carrying out the cutting solution on the bus 23 . The second controller 22 receives the control signals, and controls the drive valves 27 to cause feed wheels 11 a , 11 b , and 12 to drive the stem to each cutting position, where the second controller 22 awaits activation of the selected saw 15 or 16 by the operator before executing the cut and proceeding to the next cutting position. In another embodiment the second controller 22 may cause the saw 15 or 16 to be automatically activated at each position unless overridden by the operator.
[0073] FIG. 4A and FIG. 4B illustrates an exemplary cutting solution for optimizing value of a stem and reducing processing time for same. FIG. 4A illustrates a stem 400 having a measured length of 13.1 m.
[0074] Exemplary values of various log lengths are outlined in the following Table 1:
[0000]
TABLE 1
Log length (m)
Value ($)
4.0
500
4.5
550
5.0
400
5.5
450
6.0
500
6.5
550
7.0
600
12.0
950
[0075] For ease of illustration the value of logs are determined based solely on length, without factoring diameter into the equation.
[0076] Table 2 outlines exemplary calculated cutting priorities for the stem 400 based on the values shown in Table 1:
[0000]
TABLE 2
Priority
Value ($)
Log Composition
Total Length (m)
1
1600
2 × 4.5 m; 1 × 4.0 m
13.0
2
1550
1 × 4.5 m; 2 × 4.0 m
12.5
3
1500
3 × 4.0 m
12.0
[0077] In FIG. 4B it may be seen that in addition to logs 401 a , 401 b and 401 c , a waste portion 402 is produced by cutting solution priority 1 . Cutting positions 403 a , 403 b and 403 c are also marked.
[0078] Using standard prior art control techniques, the stem 400 would be driven from a position in which the top saw 16 was substantially aligned with the Small End Diameter (SED) to a position in which the main saw 15 was substantially aligned with the Large End Diameter (LED). The stem would then be driven to align the main saw 15 with cutting position 403 a , and log 401 a cut. The stem would then be driven to align the main saw 15 with cutting position 403 b , and log 401 b cut. The stem would then be driven to align the top saw 16 with cutting position 403 c , and log 401 c cut.
[0079] Designating the distance between the main saw 15 and the top saw 16 on the harvester head 4 as X, the total distance travelled (d) using the prior art technique in this example may be calculated as:
[0000] d =(13.1 m− X )+4.5 m+4.5 m+(4.0 m− X )=26.1 m−2 X.
[0080] In turn, using the exemplary control method 300 the diameter (D) of the stem at cutting positions 403 a , 403 b and 403 c is compared with the cutting capacity of the top saw 15 (CCT). In this example, it is determined that the diameter of the stem at cutting positions 403 b and 403 c is less than the cutting capacity of the top saw 15 . Only cutting position 403 a requires cutting using the main saw 16 .
[0081] Starting from the same position as the example discussed above, the stem 400 would be driven from a position in which the top saw 15 was substantially aligned with the SED to a position in which the top saw 15 aligned with cutting position 403 c , and the waste portion 402 cut. The stem would then be driven to align the top saw 15 with cutting position 403 b , and log 401 c cut. The stem would then be driven to align the main saw 16 with cutting position 403 a , and logs 401 a and 401 b cut.
[0082] The total distance travelled (d) using the exemplary method 300 may be calculated as:
[0000] d =0.1 m+4.0 m+(4.5 m− X )=8.6 m− X.
[0083] Using the present disclosure, in this example the harvester travels 17.5 m (less the distance between saws) less than previously required.
[0084] Aspects of the present disclosure have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.
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A system, device, and method for processing a length of material are provided. A material-working device has first and second cutting devices, each having different cutting capacities. Data relating to the length and diameter at a plurality of points of the material is received, and used to determine at least one cutting position along its length. The diameter of the length of material at the cutting position is determined, and used to select either the first cutting device or second cutting device for use in performing a cut at the cutting position based on the cutting capacity of each cutting device.
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BACKGROUND OF THE INVENTION
The present invention concerns private telephone installations, in particular key systems and small time-division switches.
Installations of this kind serve a plurality of telephones and terminals and are conventionally connected by telephone subscriber lines to a local central office, usually forming part of a telephone network, to enable the telephones and terminals connected to the installation to communicate with telephones and terminals connected to the network but not to the installation.
Telephone installations of this kind are increasingly using time-division switching which entails encoding speech signals into digital form and which is well suited to transmission of voice or data on the same transmission media, according to changing user requirements.
Installations of this kind are managed by control units each based on at least one processor associated with a set of read-only and/or random access memories (ROM and/or RAM), the various units of the installation being connected with a specific architecture to the control unit managing them. Architectures designed for large telephone central offices are not necessarily suitable for smaller installations and are likely to lead to solutions which are expensive and which do not meet optimally the requirements of users.
SUMMARY OF THE INVENTION
The invention therefore proposes a private telephone installation architecture, in particular for key systems and small time-division switches, incorporating a central unit including a digital switching network based on at least one time-division switching matrix and controlled by a control unit conventionally based on at least one processor, a set of random access and/or read-only memories and a clock, and which is adapted to enable communication by a plurality of telephones or terminals either directly by means of the switching network that it comprises, if these telephones or terminals are connected directly to it, or by means of telephone lines which connect said installation to at least one local central office of a telephone network, the telephones, terminals or lines being connected to termination circuits of the installation by means of which they are connected to the switching network via at least one time-division multiplex link and to the control unit, characterized in that it comprises a two-wire bidirectional signalling link time-shared between all the termination circuits for interchange of signalling with the control unit to which the signalling link is directly connected at a serial-parallel converter circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, its characteristics and its advantages are specified in the following description relating to the single figure described below.
The single figure shows a telephone installation architecture in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The telephone installation shown in the single figure is designed to connect a plurality of telephones and terminals 1 through a central unit 2 to each other and optionally to other identical or compatible telephones or terminals forming part of a telephone network interconnecting such installations and to which the installation in question is connected.
The telephones may be conventional analog or digital telephones, essentially intended for speech communications, or telephones specifically designed for speech and data communications and communication with electronic data processing and other information technology equipments, or dedicated terminals such as facsimile machines or electronic telephone directory terminals.
In the embodiment described as an example the telephones or terminals 1 are of the dedicated kind and each is adapted to be connected to the installation by two pairs of wires of which one pair is used to transmit so-called conversation signals (switched data or voice signals) and the second pair is used to supply power to the telephone or terminal 1 from the central unit 2 of the installation and for the interchange of signalling between the telephones or terminals 1 and the central unit 2. As is well known, this kind of connection significantly enhances information and operating capability without requiring a totally digital installation of the integrated services private network kind.
The central unit 2 in this instance includes a digital switching network 3 based on at least one time-division switching matrix. The switching network 3 is controlled by a control unit 4 conventionally based on at least one processor 5, a set of random access and/or read-only (ROM and/or RAM) memories 6 and a clock 7. In the example shown, the control unit 4 also includes centralized auxiliaries, in particular a series-parallel converter 8 and a signalling auxiliary (generator or receiver) unit 9. A multiwire bus 10 interconnects the various units constituting the control unit 4 and controls the switching network 3 responsible for interconnecting the various telephone termination circuits of the installation connected to it by at least one bidirectional multiplex link 12 and, in this case, concentrator interfaces 33.
These termination circuits include individual line interface circuits 30 for the telephone or terminals 1, central office line interface circuits (hereinafter: OLIC) 31 for connecting the installation to a local central office (not shown) via telephone lines 32 and optionally various dedicated termination circuits 11, for example for tie lines between central offices.
The switching network 3 comprises, for example, a time-division switching matrix adapted to interconnect eight bidirectional multiplex links 12 with two wires MBE, MBR used separately for respective transmission directions and each providing 32 time slots with a data rate of 64 kbit/s carrying the voice-data signals in the form of bytes. Seven of the multiplex links 12 service the telephone terminations, that is the line interface circuits 30, the central office line interface circuits 31 and the termination circuits 11, via the corresponding concentrator interfaces 33; the remaining multiplex link services in one direction the generators and in the other direction the receivers which together constitute the signalling auxiliary unit 9.
A signalling link 13 independent of the switching network 3 handles interchange of signalling information within the installation between the control unit 4 and the termination circuits via the concentrator interfaces 33. This time-division multiplexed signalling link 13 is a two-wire link connected to the series-parallel converter 8 of the control unit 4. The converter 8 serializes information corresponding to requests (grouped requests in this instance) sent over the signalling multiplex link 13 from the control unit 4 in which this information is transmitted in parallel via the bus 10 and converts to parallel form information corresponding to responses, also grouped, received in serial form by the control unit 4 via the signalling link 13.
In one embodiment the data rate of the signalling link 13 is on the order of 2 Mbit/s and 256 time slots are available in each frame on each of the two wires MSR and MSE, one transmitting requests from the control unit 4 acting as the master unit via the converter 8 and the other the responses, the clock 7 providing the necessary timing signals. The signalling link 13 frame is in this instance the same length as the frame for time-division switching the voice-data signal samples in the switching network 3.
All signalling is grouped together in a memory of the set 6 which stores temporarily in a first half control bytes which correspond to actions at the termination circuits and in a second half monitoring bytes which correspond to status indications supplied in return by the termination circuits, this second half being in turn divided into two parts respectively reserved for monitoring relating to signalling received from termination circuits and monitoring relating to the type of these termination circuits.
In the embodiment described all termination circuits and auxiliaries connected to the signalling link 13 are processed cyclically within an overall period of 1 ms (eight frames).
A termination circuit is reserved at least one byte in a frame in each transmission direction on the signalling link 13, the bits of the two bytes concerning the same termination circuit being transmitted simultaneously in opposite directions.
In this example the termination circuits are grouped into modules according to their type and each module (comprising, for example eight line interface circuits 30 or four central office line interface circuits 31) can use successive bytes on the signalling link 13, the modules being grouped according to which multiplex link 12 transmits their voice-data signals.
As explained above, concentrator interfaces 33 connect the termination circuits to the multiplex links 12 servicing them and to the common signalling link 13. Two concentrator interfaces 33A and 33B are shown by way of example in FIG. 1, the first servicing a COLIC 31 module and the second servicing a designated telephone or terminal 1 module. Both essentially comprise a synchronization circuit 14 and a signalling circuit 15.
Each synchronization circuit 14 handles the transmission and reception of voice-data signals using the time slots reserved on one of the multiplex links 12 for all the termination circuits of the module that it serves and transmission to these termination circuits via a common link with two wires BE and BR respectively used for transmission and reception, and it further recovers or creates various timing and reset signals needed by the module which it services from the signals transmitted from the control unit 4 and in particular from the clock 7 over the link H.
The synchronization circuit will not be described in complete detail here as it is a standard circuit and its design will be obvious to those skilled in the art given that the clock signals received from the central unit are a bit clock signal for example at a frequency of 2 MHz, a frame clock signal transmitted by the link H and a reset signal transmitted by the link RZG.
Each signalling circuit 15 handles serial transmission and reception on one or other wire of the signalling link 13 of signalling data interchanged between the module that it services and the control unit 4. To this end it receives from the control unit 4 a clock signal (at 4 MHz in this example) via the link H and respective enabling signals for activating the modules that it services at times reserved for each module on the multiplex link 13 and for transmission of data characteristic of the type of module to the central unit. In this example this transmission takes place in alternate signalling frames. In this example the data is transmitted serially via the signalling link 13 and transmitted or received in parallel by the synchronization circuit 14 to or from the associated termination circuits.
The concentrator interfaces 33A and 33B are different in that they have different auxiliary arrangements related to the specific characteristics of the termination circuits that they service, in addition to their identical synchronization circuits 14 and signalling circuits 15.
The interface 33A servicing a COLIC 31 module comprises at least one multiplexer 16 adapted to receive in parallel form the monitoring information usually transmitted by dedicated and individual links in the form of current or voltage binary signals from the COLICs in order to retransmit them serially on the signalling link 13, and at least one buffer register (not shown) for transmission of control data to the termination circuits of the module.
In this example the interface 33B services a dedicated telephone or terminal 1 line interface circuit 30 module and includes a microcontroller 34 which handles the transfer of control and monitoring binary data between the signalling circuit 15 and the line interface circuits 30 of the module, it being understood that the signalling circuit is adapted to supply or to receive this data in parallel form and that the line interface circuits are adapted to transmit or receive this data in the form of serial messages transmitted on a single wire in each direction per line interface circuit; in the example being described each message transmitted includes a start bit and an end bit between which the data is placed, together with a parity check bit.
Consequently, it is the microcontroller 34 which handles the various operations needed for such transmissions. The line interface circuits 30 and the COLICs 31 serviced are designed to be connected in the former case to the two pairs of wires of a dedicated telephone or terminal 1 and in the latter case to the two wires of a telephone line 32 connected to a local central office (not shown).
The wires A, B of a telephone line are conventionally connected to a protection circuit 17 of the COLIC at which they terminate, this device providing protection against any overvoltages that may be applied to the line accidentally.
This device comprises, for example, two equal-value capacitors in series between the wires A, B on the input side of two inductive circuits, one on each of the two wires and each comprising one of the two windings of a transformer and a resistor shunting that winding, the device being conventionally completed by a surge arrestor diode connected between the wires on the output side of the inductive circuits. The capacitors and the inductive circuits protect the COLIC from radio frequency interference and the diode and the capacitors protect the COLIC and the circuits on its output side against any overvoltages transmitted by the line. A charging pulse detector 18, a ringing detector 19 and a transmission bridge 20 are connected in parallel to the two wires A, B of the telephone line 32 via the protection device 17 in each COLIC 31.
Binary signals AP and DTX respectively characterizing detection of ringing and charging pulses are separately provided in the form of current or voltage levels by the detectors 18 and 19 to the multiplexer 16 of the corresponding concentrator interface 33A via individual links such as the links AP1 and DTX1 for the COLIC 31 of rank 1. They are transmitted to the signalling circuit 15 in the form of a series of bits time-division multiplexed by the multiplexer 16.
The tone detector 24 is designed to sense dial tone signals transmitted as sinusoidal signals in the frequency band between 300 and 500 Hz. It is usually based on one or more filters and connects to the output of the converter-matching circuit 21 of the COLIC 31 which incorporates it, on the transmit wire to the cofidec circuit 23 of the circuit 21. It will not be described in any more detail as it can be one of the conventional circuits well known to those skilled in the art.
The charging pulse detector 18 is designed to sense charging pulses transmitted on the telephone line 32 from the local central office at which the line terminates. It detects very low frequency (12 or 16 kHz, for example) charging pulses conventionally transmitted in differential mode by the local central office on the two wires A, B of the line 2 or charging pulse signals transmitted at extremely low frequency (50 Hz for example) and in common mode on the same line wires by the local central office. It can be based on one or more filters in one of the usual arrangements that will not be described here as they are familiar to those skilled in the art and are not directly related to the invention.
The transmission bridge 20 essentially comprises a polarity detector adapted to signal to the signalling circuit 15, by means of a binary signal IB sent on the IB1 line, reversals of the polarity of the battery voltage applied to the telephone line 32 by the local central office at which the line terminates. It also includes a line loopback and loop disconnect dialling detector which supplies a signal BC on the link BC1 and a line current regulator circuit, these circuits not being shown in FIG. 1. It is connected to the wires of the telephone line 2 through the protection device 17, the transmission bridge 20 and a transformer 22 in series.
The circuit 21 itself provides the link between the transformer 22 and, on the one hand, a cofidec circuit 23 connected to the synchronization circuit 14 which serves the COLIC 31 of which it forms part and, on the other hand, a tone detector 24 of the COLIC 31. The circuit 21 is based on operational amplifiers with one amplifier in the transmit channel to the cofidec circuit 23 and another in the receive channel for analog signals produced by the cofidec circuit 23. A balancing network conventionally implemented with resistors and capacitors matches the COLIC to the various lines to which it may be connected. The transformer 22 conventionally isolates the circuits connected to one of its two windings from those connected to the other and also provides bidirectional transmission of alternating current signals (in particular those in the telephone band).
The circuit 23 is a conventional coder-filter-decoder which converts into the form of analog signals that can be transmitted on a telephone line such as the line 32 voice-data digital signals supplied in the form of bytes by the associated synchronization circuit 14 via the time-division multiplex link formed by the wire BE, in turn connected to the wire MBE of the multiplex link 12, and also converts into digital signals analog signals supplied over the telephone line 32 for their successive transmission on the wires BR and MBR. For this purpose the circuit 23 receives the clock signals via the link H and a channel time slot select signal FSX via an individual link, for example the link FSX1 for the circuit 1, to enable it to effect the transmissions in which it is involved. In the present example this circuit is, for example, a NATIONAL SEMICONDUCTORS TP 3057 with serial input and output.
One of the two pairs of wires from a dedicated telephone or terminal 1 is connected to an arrangement including a cofidec circuit 37 in series with an impedance matching and two-wire/four-wire converter circuit 36 and a protection device 35. In this example the cofidec circuit 37 is of the same type as the cofidec circuit 23 of a COLIC, and the same goes for the matching/converter circuit 36. On the other hand, the protection device has only to pass alternating current signals, the telephone or the terminal not being powered by this pair of wires. It therefore comprises a capacitor for transmitting alternating current voice-data signals on each of the two wires which connect it to the matching converter circuit 36, these capacitors blocking any DC component accidentally emanating from the telephone or terminal.
The second pair of wires from a telephone or terminal 1 terminates at a signalling arrangement 38 via a protection device 39 analogous to the device 17 of a COLIC. It provides at least partial remote power feed to the telephone or terminal 1 and transmits signalling messages (asynchronous serial symmetrical digital signals) between the telephone or terminal and the signalling arrangement 38 of the line interface circuit 30 to which it is connected.
Signalling messages are interchanged by superimposing them on the remote power feed to the telephone or terminal in half-duplex asynchronous mode. In the direction from the microcontroller 34 to the telephone or terminal the latter receives an interrogation or control message from the control unit 4 and responds with a monitoring message indicating, for example, that the telephone is idle or that one of its keys (not shown) has been pressed.
The signalling arrangement 38 includes a modulator and a demodulator (not shown). The modulator comprises, for example, two transistors configured as a current generator driving said second pair of wires, its input being driven by the signal placed by the microcontroller 34 on the wire SE.
The demodulator is based on a comparator receiving at its inputs the falling pulses transmitted by whichever of the two wires of the second pair is at the positive supply voltage and the rising pulses transmitted by the other wire of the second pair, which is at the negative supply voltage. A hysteresis threshold detector made up of three resistors and two capacitors in series between the wires of said second pair transmits these pulses to the inputs of the comparator, each of which inputs is connected to one end of the center resistor of the detector and to one of the wires via one of the capacitors and a different resistor of the detector. The comparator generates a digital signal on the wire SR connecting it to the microcontroller which services it, according to the hysteresis signal resulting from the pulses applied to its inputs.
The microcontroller 34 is an HITACHI HMS412C, for example, comprising a processor unit associated with working RAM and a mask-programmed memory for its operating software, a timer supplying a real time clock signal, for example every 156 μs, the clock of the microcontroller operating at the speed of the 2 MHz clock. Two transmitter/receiver circuits are used in this example to service four line interface equipments, for example.
Bidirectional dialogue at a transmitter-receiver circuit is effected in this example by load sharing in four phases. During a first phase the transmitter sends a control message on the second pair of a first telephone or terminal line while the associated receiver receives a signalling message via the second pair of a fourth telephone or terminal line.
During a second phase the transmitter sends a control message on the second pair of a second telephone or terminal line while the associated receiver receives a signalling message via the second pair of the first line.
During a third phase the transmitter sends a control message on the second pair of the third telephone or terminal line while the associated receiver receives a signalling message via the second pair of the second line.
During a fourth phase the transmitter sends a control message on the second pair of the fourth telephone or terminal line while the associated receiver receives a signalling message via the second pair of the third line.
The microcontroller 34 is also connected to the synchronization circuit 15 which services it by write and read control links ECR and LEC, by a bidirectional data link which transmits the data in parallel, byte by byte, and by a clock link HE and a reset link RZ, both the latter originating at the signalling circuit 15.
The types of termination circuit that a concentrator interface 33 processes is in this example indicated cyclically to the control unit 4 by the signalling circuit 15 of the interface which to this end has type identification inputs to be specifically hardwired, as is usual in this art.
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The invention concerns private telephone instalations, in particular key systems or small time-division switches, each provided with a central unit (2) including a time-division digital switching network (3) controlled by a control unit (4) to enable communication of a pluality of telephone or terminals (1) either directly by means of the switching network or by means of telephone lines (32) terminating at a local central office, the telephones or terminals or lines being connected to termination circuits (30, 31) which connect them to the switching network (3) via at least one time-division multiplex link (12) and to the control unit (4). A two-wire bidirectional signalling link (13) is time-shared between all the termination circuits for interchanges of signaling with the control unit (4); it is connected direct to a series-parallel converter circuit (8).
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TECHNICAL FIELD
[0001] The present invention relates to a method of controlling wireless communication that controls a portable audio apparatus by performing short-range wireless communication, a wireless communication control apparatus, and an in-vehicle audio apparatus.
BACKGROUND ART
[0002] As a conventional audio apparatus that performs control of a portable audio apparatus by performing short-range wireless communication, a speaker system including a wireless receiving pack and a speaker unit is known (e.g. see patent literature 1). The wireless receiving pack receives an audio signal from the portable audio apparatus using Bluetooth (registered trademark, applies similarly hereinafter) communication, which is a short-range radio. The speaker unit is connected to this wireless receiving pack, and, upon receiving this audio signal, outputs the audio signal as a sound.
CITATION LIST
Patent Literature
PTL 1
[0000]
Japanese Patent Application Laid-Open No. 2007-336511 (paragraph 32 to paragraph 34)
SUMMARY OF INVENTION
Technical Problem
[0004] Conventionally, a portable audio apparatus of a conventional device and an in-vehicle audio apparatus used by installing it in a vehicle have been caused to communicate wirelessly and reproduce data of the portable audio apparatus in the in-vehicle audio apparatus, that is, an operation of the portable audio apparatus using an operating section of the in-vehicle audio apparatus has been performed.
[0005] However, when a portable audio apparatus is operated via an in-vehicle audio apparatus like this, cases occur where the user is unable to operate the portable audio apparatus as he or she desires.
[0006] The reasons include the following. In the operating section of the in-vehicle audio apparatus, typically, a play button that controls the portable audio apparatus into a playing state and a pause button that controls the portable audio apparatus into either a stopped state or a paused state are allotted to one common button (hereinafter referred to as “play/pause button”). This is to make efficient use of a limited space inside a vehicle.
[0007] Thus, when the play/pause button is pressed while the portable audio apparatus is playing, the in-vehicle audio apparatus must have the play/pause button to operate as a pause button. Further, when the play/pause button is pressed at a time other than when the portable audio apparatus is playing, the in-vehicle audio apparatus must have the play/pause button to operate as a play button.
[0008] However, among in-vehicle audio apparatuses, there are apparatuses in which operation states of the portable audio apparatus such as “playing,” “stopped,” “paused,” “fast-forwarding,” “rewinding,” etc. cannot be acquired. By this means, with a conventional in-vehicle audio apparatus, there is a problem that a control signal that does not match the operation state of a portable audio apparatus is sent (for example, a signal commanding to stop is sent to the portable audio apparatus while the portable audio apparatus is stopped, etc.), and this confuses the operator.
[0009] It is therefore an object of the present invention to provide a method of controlling wireless communication, a wireless communication control apparatus, and an in-vehicle audio apparatus that are capable of accurately controlling a portable audio apparatus by using one button.
Solution to Problem
[0010] The method of controlling wireless communication according to the present invention is a control method to control a portable audio apparatus through wireless communication. The method has a configuration that includes the steps of: receiving information from the portable audio apparatus; determining whether or not it is possible to acquire an operation state of the portable audio apparatus from the received information; judging a streaming state in the portable audio apparatus from the received information when it is not possible to acquire the operation state of the portable audio apparatus; transmitting a stop signal for stopping a playback operation of the portable audio apparatus to the portable audio apparatus when an operation section is operated and streaming is in progress in the portable audio apparatus; and transmitting a playback signal for starting the playback operation of the portable audio apparatus to the portable audio apparatus when the operation section is operated and streaming is not in progress in the portable audio apparatus.
[0011] According to this configuration, even when it is not possible to acquire the operation state of the portable audio apparatus from the portable audio apparatus, it is possible to judge the operation state based on the streaming state in the portable audio apparatus, the operation state of the portable audio apparatus can be controlled into an accurate operation state.
[0012] Further, the wireless communication control apparatus of the present invention has a configuration that comprises: a receiving section that receives a signal representing a streaming state in the portable audio apparatus transmitted from the portable audio apparatus; a determining section that determines the streaming state in the portable audio apparatus from the signal received by the receiving section; and a transmitting section that transmits an operation command signal to the portable audio apparatus, the operation command signal being for switching an operation state of the portable audio apparatus in accordance with an operation signal of an operation section connected to the wireless communication control apparatus; wherein the operation command signal includes a stop command signal for stopping a playback operation of the portable audio apparatus and a playback command signal for starting the playback operation of the portable audio apparatus, the transmitting section transmits the stop command signal to the portable audio apparatus when the operation section is operated and streaming is in progress in the portable audio apparatus, and transmits the playback command signal to the portable audio apparatus when the operation section is operated and streaming is not in progress in the portable audio apparatus.
[0013] Further, the wireless communication control apparatus of the present invention has a configuration that uses Bluetooth communication as a wireless communication method between the portable audio apparatus and the wireless communication control apparatus.
[0014] Further, the in-vehicle audio apparatus of the present invention has a configuration that comprises: a receiving section that receives a signal representing a streaming state in the portable audio apparatus transmitted from the portable audio apparatus; a determining section that determines the streaming state in the portable audio apparatus from the signal received by the receiving section; a single operation button that receives a command to stop a playback operation of the portable audio apparatus and to start the playback operation of the portable audio apparatus from an operator; a detecting section that detects the operation button having been operated; and a transmitting section that transmits an operation command signal to the portable audio apparatus, the operation command signal being for switching the operation state of the portable audio apparatus in accordance with a detection result of the detecting section. In this apparatus, the operation command signal includes a stop command signal for stopping a playback operation of the portable audio apparatus and a playback command signal for starting the playback operation of the portable audio apparatus, the transmitting section transmits the stop command signal to the portable audio apparatus when the operation button is operated and streaming is in progress in the portable audio apparatus, and transmits the playback command signal to the portable audio apparatus when the operation button is operated and streaming is not in progress in the portable audio apparatus.
[0015] According to this configuration, even when it is not possible to acquire the operation state of the portable audio apparatus from the portable audio apparatus, it is possible to judge the operation state based on the streaming state in the portable audio apparatus, so that the operation state of the portable audio apparatus can be controlled into the accurate operation state by using a single button.
Advantageous Effects of Invention
[0016] By this means, the present invention determines, from a portable audio apparatus connected with an audio apparatus through wireless communication, whether music data is streaming on the wireless communication. By this means, the present invention can provide an audio apparatus that accurately judges the operation state of the portable audio apparatus even if the portable audio apparatus is one of those from which the operation states such as playing, stopped, and paused cannot be acquired, and by which the portable audio apparatus can be accurately controlled by a single operation button.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a block diagram of an audio apparatus of an embodiment of the present invention;
[0018] FIG. 2 is a flow chart illustrating an operation of the audio apparatus of the present embodiment; and
[0019] FIG. 3 is an application diagram of other audio apparatuses of the present embodiment.
DESCRIPTION OF EMBODIMENTS
[0020] Hereinafter, an audio apparatus of an embodiment of the present invention will be described with reference to the accompanying drawings.
[0021] The function blocks of an in-vehicle audio apparatus according to an embodiment of the present invention is shown in FIG. 1 .
[0022] In the embodiment of the present invention, Bluetooth communication is used as short-range wireless communication between a portable audio apparatus and the audio apparatus.
[0023] In FIG. 1 , in-vehicle audio apparatus 1 as the in-vehicle audio apparatus is composed of communication module 2 , micro controller unit 3 , display device 4 , operating section 5 , audio processor 6 , speaker 7 and antenna 8 . Portable audio apparatus 9 as a portable audio apparatus is connected to in-vehicle audio apparatus 1 .
[0024] Communication module 2 is a Bluetooth module. Antenna 8 is a Bluetooth antenna. Further, portable audio apparatus 9 is a Bluetooth audio apparatus. That is, portable audio apparatus 9 is connected to in-vehicle audio apparatus 1 using a Bluetooth audio connection through Bluetooth communication 10 .
[0025] Communication module 2 is, for example, a wireless communication control apparatus formed with a plurality of micro controller units. The micro controller units to constitute communication module 2 include, for example, a micro controller unit as a determining section for performing a profile connection of a Bluetooth audio profile defined by the Bluetooth audio profile. Further, the micro controller units to constitute communication module 2 include a micro controller unit for decoding Bluetooth audio music data defined by the Bluetooth audio profile (hereinafter simply referred to as “music data”). Antenna 8 is a receiving section and a transmitting section that inputs and outputs radio waves to realize Bluetooth communication. Micro controller unit 3 includes a detecting section that controls communication module 2 based on an operation signal generated in response to an operation by an operator at operating section 5 . Display device 4 displays play information such as music title information, playing time information, etc., that are transmit via communication module 2 and micro controller unit 3 from portable audio apparatus 9 .
[0026] Operating section 5 is connected to micro controller unit 3 using a bus connection, and is formed with a play/pause button, a fast-forward button, a rewind button, etc. The play/pause button is a single operation button in which a play button for switching an operation state of portable audio apparatus 9 (hereinafter referred to as “operated-side operation state”) to “playing” and a pause button that controls the operated-side operation state to be either “stopped” or “paused” are in common. That is, the play/pause button receives a command to change the operation state of portable audio apparatus 9 from the operator. The fast-forward button is a button for controlling the operated-side operation state to be fast-forwarding. The rewind button is a button for controlling the operated-side operation state to be rewinding. Micro controller unit 3 detects operation information generated as a result of the operator pressing operating section 5 , and transmits the detected operation information to communication module 2 via a serial communication.
[0027] Communication module 2 converts the operation information received from micro controller unit 3 to a Bluetooth audio command defined by the Bluetooth audio profile, and transmits the same to portable audio apparatus 9 . By this means, communication module 2 ca control portable audio apparatus 9 .
[0028] On the other hand, the music data is encoded in portable audio apparatus 9 , and is sent to communication module 2 via antenna 8 . Then, communication module 2 decodes the music data, and outputs the same to audio processor 6 .
[0029] Audio processor 6 is an audio processor that performs signal processing on the music data input from communication module 2 and outputs the same to speaker 7 .
[0030] Next, the operation of in-vehicle audio apparatus 1 configured as above will be described with reference to FIG. 2 .
[0031] For example, in-vehicle audio apparatus 1 and portable audio apparatus 9 are connected using Bluetooth audio connection as aforementioned, and the operated-side operation state is playing. Further, the operation state of in-vehicle audio apparatus 1 is in the playing state, and a Bluetooth audio of portable audio apparatus 9 is output (streaming is in progress) from speaker 7 of in-vehicle audio apparatus 1 . At this occasion, the operator may e.g. wish to bring portable audio apparatus 9 to a stopped/paused state, and press a play/stop button of in-vehicle audio apparatus 1 .
[0032] Further, although in-vehicle audio apparatus 1 and portable audio apparatus 9 are connected using Bluetooth audio connection, the operated-side operation state and the operation state of in-vehicle audio apparatus 1 are both being stopped (streaming is not in progress). At this occasion, the operator may e.g. wish to bring portable audio apparatus 9 to the playing state, and press the play/stop button of in-vehicle audio apparatus 1 .
[0033] When the play/stop button of in-vehicle audio apparatus 1 is pressed, operating section 5 generates the operation information that indicates that the play/stop button has been pressed (S 1 ).
[0034] Micro controller unit 3 detects the operation information that indicates that the play/stop button has been pressed (hereinafter referred to as “press information”). Communication module 2 receives the press information detected by micro controller unit 3 from micro controller unit 3 .
[0035] As a result of this, based on the press information received from micro controller unit 3 , communication module 2 decides whether to transmit a playback command, or one of a pause command and a stop command to portable audio apparatus 9 through processing as below in respective steps.
[0036] Here, the playback command is a Bluetooth audio control command (a playback signal) defined by the Bluetooth audio profile for causing a playback operation. Further, the pause command is a Bluetooth audio control command (a pause signal) defined by the Bluetooth audio profile for causing a pausing operation. Further, the stop command is a Bluetooth audio control command (a stop signal) defined by the Bluetooth audio profile for causing a stopping operation.
[0037] In-vehicle audio apparatus 1 judges whether or not Bluetooth audio connection has been established with portable audio apparatus 9 (S 2 ). In-vehicle audio apparatus 1 makes this judgment by judging whether or not the Bluetooth audio profile connection defined by the Bluetooth audio profile is established with portable audio apparatus 9 .
[0038] When portable audio apparatus 9 is not connected to in-vehicle audio apparatus 1 using Bluetooth audio connection (S 2 : “NO”), in-vehicle audio apparatus 1 proceeds to step S 10 . Here, in-vehicle audio apparatus 1 does not transmit any of the aforementioned commands to portable audio apparatus 9 (S 10 ). In this case, in-vehicle audio apparatus 1 transmits, to display device 4 via micro controller unit 3 , information indicating that portable audio apparatus 9 is not connected, and displays the same for the operator.
[0039] When portable audio apparatus 9 is connected to in-vehicle audio apparatus 1 using Bluetooth audio connection (S 2 : “YES”), in-vehicle audio apparatus 1 proceeds to step S 3 . Here, communication module 2 judges whether or not portable audio apparatus 9 supports an operation state acquisition command. Here, the operation state acquisition command is a command defined by the Bluetooth audio profile that requests another apparatus to return its operation state. That is, communication module 2 judges whether or not portable audio apparatus 9 is an apparatus from which the operation state thereof can be acquired by communication module 2 (S 3 ). Communication module 2 makes this judgment based on a version of the Bluetooth audio profile of portable audio apparatus 9 as defined by the Bluetooth audio profile.
[0040] When portable audio apparatus 9 is an apparatus from which the operation state (the operated-side operation state) thereof can be acquired (S 3 : “YES”), communication module 2 acquires a signal indicating the operated-side operation state from portable audio apparatus 9 . Then, communication module 2 judges whether or not the operated-side operation state indicated by the acquired signal is playing, and decides a command to be sent based on a judgment result. That is, communication module 2 decides which one of the playback command, the pause command and the stop command is to be sent to portable audio apparatus 9 based on the operated-side operation state (S 4 ).
[0041] When it is judged that the operated-side operation state is playing (S 4 : “YES”), communication module 2 transmits the pause command to portable audio apparatus 9 (S 6 ).
[0042] Further, when it is judged that the operated-side operation state is other than playing (S 4 : “NO”), communication module 2 transmits the playback command to portable audio apparatus 9 (S 7 ).
[0043] When portable audio apparatus 9 is an apparatus from which the operation state (the operated-side operation state) thereof cannot be acquired (S 3 : “NO”), communication module 2 acquires a signal indicating a Bluetooth audio streaming state of portable audio apparatus 9 (hereinafter referred to as “streaming state”) from portable audio apparatus 9 . Here, the streaming state is information indicating whether or not the music data defined by the Bluetooth audio profile is output through the wireless communication. Communication module 2 judges whether or not the streaming state indicated by the acquired signal is streaming, and decides a command to be sent based on a judgment result. That is, communication module 2 decides which one of the playback command, the pause command and the stop command is to be sent to portable audio apparatus 9 based on the streaming state (S 5 ).
[0044] When it is judged that the streaming state is streaming (S 5 : “YES”), communication module 2 transmits the stop command to portable audio apparatus 9 (S 8 ).
[0045] Further, when it is judged that the streaming state is other than streaming (S 5 : “NO”), communication module 2 transmits the playback command to portable audio apparatus 9 (S 9 ).
[0046] By this means, in-vehicle audio apparatus 1 of the embodiment of the present invention can accurately grasp the operation state of portable audio apparatus 9 that is connected with in-vehicle audio apparatus 1 using Bluetooth connection. By this means, in-vehicle audio apparatus 1 has the play button and the pause button as a common button, and in the configuration of controlling the operation state of portable audio apparatus 9 by receiving operations on this button, the operation of portable audio apparatus 9 can be controlled appropriately.
[0047] Note that, in the foregoing explanation, the description had been made based on an example with a configuration in which communication module 9 for controlling portable audio apparatus 2 is arranged inside in-vehicle audio apparatus 11 , however, the configuration of a system to which the present invention is to be applied is not limited to this. For example, as shown in FIG. 3 , communication module 13 as the Bluetooth module may be arranged outside in-vehicle audio apparatus 11 or the like as the audio apparatus, and may control portable audio apparatus 15 as the Bluetooth audio apparatus via in-vehicle audio apparatus 11 or the like. That is, the present invention can similarly be implemented even in a configuration in which in-vehicle audio apparatus, etc. 11 controls portable audio apparatus 15 indirectly through wireless communication 14 . In this case, for instance, communication module 13 is connected via in-vehicle audio apparatus 11 and LAN 12 .
INDUSTRIAL APPLICABILITY
[0048] As described above, the wireless communication control method, wireless communication control apparatus and in-vehicle audio apparatus of the present invention are designed to acquire, from a portable audio apparatus wirelessly connected with an in-vehicle audio apparatus, whether or not music data is output through wireless communication. By this means, even with a portable audio apparatus from which the operation state such as playing, stopped and paused cannot be acquired, the wireless communication control method, wireless communication control apparatus and in-vehicle audio apparatus of the present invention can accurately judge the operation state of the portable audio apparatus. By this means, the wireless communication control method, wireless communication control apparatus and in-vehicle audio apparatus of the present invention can accurately judge the operation state of the portable audio apparatus with a single button.
[0049] By this means, the present invention is useful in applying to an audio apparatus, etc. that controls a portable audio apparatus by performing short-range wireless communication.
REFERENCE SIGNS LIST
[0000]
1 IN-VEHICLE AUDIO APPARATUS
2 COMMUNICATION MODULE
3 MICRO CONTROLLER UNIT
4 DISPLAY DEVICE
5 OPERATING SECTION
6 AUDIO PROCESSOR
7 SPEAKER
8 ANTENNA
9 PORTABLE AUDIO APPARATUS
11 IN-VEHICLE AUDIO APPARATUS
12 BUS/LAN
13 COMMUNICATION MODULE
15 PORTABLE AUDIO APPARATUS
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Disclosed is an in-vehicle acoustic device capable of accurately controlling the operating state of a portable acoustic device with one button. An in-vehicle audio device ( 1 ) serving as the in-vehicle acoustic device is equipped with an antenna ( 8 ) which receives a signal indicating the streaming state of a portable audio device ( 9 ), and a communication module ( 2 ) which transmits operating instruction signals to the portable audio device ( 9 ) according to operating signals from an operating unit ( 5 ). When the operating unit ( 5 ) is operated and the portable audio device ( 9 ) is streaming, the communication module ( 2 ) transmits a stop instruction signal to stop playback operation by the portable audio device ( 9 ), and when the operation unit ( 5 ) is operated and the portable audio device ( 9 ) is not streaming, the communication module transmits a play instruction signal to start playback operation by the portable audio device ( 9 ). In addition, the in-vehicle audio device ( 1 ) uses Bluetooth communication as the method for wireless communication between the in-vehicle audio device and the portable audio device ( 9 ).
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 60/758,016, filed Jan. 11, 2006, the teachings of which are incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to a method and apparatus for the culture of cells.
BACKGROUND
[0003] Cell cultures provide for the growth and maintenance of a cell or cells in favorable conditions. Cells may include hybridomas, stem, mammalian and insect cells, among others. To grow and maintain the cells, cell nutrients, cell products and gasses may be provided to a culture.
SUMMARY
[0004] An exemplary aspect of the present invention relates to a cell growth chamber, the interior surfaces of which are adapted for the growth of cells and defining a culture space. An inlet may be defined in the cell growth chamber for providing fluid and gasses to the culture space and an outlet may be defined in the cell growth chamber for collecting the fluid and gasses from the culture space. The interior surfaces of the cell growth chamber may form a channel that is defined by a wall and a base located between said inlet and outlet.
[0005] One aspect of the present invention provides a cell culture device in which cells may be grown to a high density in a self contained apparatus.
[0006] Another aspect of the present invention provides a cell culture assembly having a plurality of growth chambers, wherein in each growth chamber may have a substantially equal distribution of nutrient medium and gasses.
[0007] Another aspect of the present invention provides a cell culture assembly that may allow for the continuous addition of nutrient medium and gasses and the removal of conditioned nutrient medium, gasses and products formed by the cells.
[0008] Another aspect of the present invention provides a flow system which may be continuous and may promote an optimal environment for the production of biochemicals, viral vaccines, antibodies and other pharmaceuticals.
[0009] Another aspect of the present invention provides a cell culture assembly that may be a self-contained device.
[0010] Another aspect of the present invention provides a cell culture assembly that may contain a variety of macro, micro and or nano structures, which may support or enhance the growth and attachment of cells and production of bio-chemicals.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The detailed description below may be better understood with reference to the accompanying figures which are provided for illustrative purposes and are not to be considered as limiting any aspect of the invention.
[0012] FIG. 1 is a perspective view of an exemplary embodiment of an assembly.
[0013] FIG. 2 is a cross sectional side view of an exemplary embodiment of an assembly.
[0014] FIG. 3 is a perspective view of an exemplary plate of the assembly.
[0015] FIG. 4 is a perspective view of an exemplary array of plates sectioned to reveal the construction of the assembly.
[0016] FIG. 5 is a perspective view of an exploded section of the structured surface of an exemplary growth area.
[0017] FIG. 6 is perspective view with section cut away to reveal an exemplary embodiment of interchamber fluid dams and fluid path.
[0018] FIG. 7 is a schematic view of an embodiment of the invention incorporated into a continuous culture system.
[0019] FIG. 8 is a perspective view of an exemplary plate of a rectangular embodiment of the invention.
[0020] FIG. 9 is a perspective view of an exemplary plate of another rectangular embodiment of the invention.
DETAILED DESCRIPTION
[0021] The present invention may provide a culturing environment, which may be continuous, in a device having a plurality of growth chambers, stacked in an array, creating a large surface area for the culture of cells at high density, interspaced with a large surface area of nutrient medium exposed to the culture gasses. The device may be constructed and arranged to permit the directional flow of nutrient medium throughout each of the growth chambers. The flow may be adequate to provide for the gentle mixing of the nutrients throughout the entire growth area of the device, while at the same time providing adequate mixing with the culture gasses to assure that proper oxygenation and gas concentration may be maintained for the growth of cells.
[0022] Preferably, the culture device may include an array of culture chambers defined by the spaces between the superpositioning of a plurality of stacked plates. An inlet conduit may be provided for the nutrient medium. An inlet conduit may be provided for the introduction of culture gasses. The nutrient medium and the culture gasses may flow together throughout the culture chamber providing a distributed flow of nutrients mixed with the culture gasses throughout the entire growth chamber and each chamber may be serially connected to the next growth chamber. The growth surfaces of each of the culture chambers, may be altered by a variety of macro, micro or nano structures as required to effect the desired culture density or the proper distribution of gasified nutrient medium to either the basal or lateral surfaces of the cells being cultured.
[0023] The cell culture device of an exemplary embodiment may include an array of culture chambers enclosed within a vessel. The vessel may also incorporate a reservoir for the culture media and gasses. The exterior view, illustrated in FIG. 1 , shows an exemplary embodiment of a vessel 10 . The vessel 10 may be substantially cylindrical. The vessel 10 may incorporate as illustrated in FIG. 2 a molded top 28 ; a molded bottom reservoir 26 and culture chambers 20 . The top 28 , culture chambers 20 , and bottom vessel 26 , may be molded together or sealed to provide a fluid-tight arrangement for the culture chambers.
[0024] Referring back to FIG. 1 , the vessel 10 may include three conduits extending from the top of the vessel 10 ; a fluid inlet conduit 11 , a gas inlet conduit 13 and a gas outlet conduit 14 . The bottom of the vessel may also contain two conduits, the fluid outlet conduit 12 and the product/waste conduit 15 . Fluid may enter the vessel 10 through inlet conduit 11 and may flow gently down a fluid path of the first culture chamber 20 . The fluid may form a stream of continuously moving and mixing fluid that may communicate with the cultured cells and may provide a continuous source of nutrients and gasses.
[0025] An exemplary embodiment of a single culture chamber is illustrated in FIG. 3 . The fluid stream may enter the culture chamber at inlet 11 and flow down the sloped inlet path 32 , moving through the structured culture chamber 20 , and arriving at the outlet conduit 22 of the first culture chamber. The gas mixture may enter the first chamber from the gas inlet 13 and may then move throughout the entire culture chamber arriving at outlet 22 .
[0026] A fluid dam 31 , illustrated in FIG. 6 , may be provided as a means to establish the depth of the fluid stream and may surround each outlet conduit 22 . The depth of the fluid stream, may be varied to enhance the flow and mixing to the structured culture surface. The fluid may flow over the dam 31 , and gently through the inlet conduit 21 and down the sloped inlet path 32 of inlet 21 of the next culture chamber FIG. 6 . The gas dam 35 , also illustrated in FIG. 6 , may prevent the flow of fluids through a section of each outlet 22 . The gasses may flow over the gas dam 35 through the inlet 21 of the next culture chamber. Each culture chamber 20 may contain a fluid dam 31 and a gas dam 35 located at the outlet of the culture chamber 22 and may include a sloped inlet path 32 located at the inlet 21 of the next culture chamber. The fluid path may repeat this process until it reaches the final outlet conduit 22 over the molded bottom reservoir 26 , illustrated in FIG. 2 . The fluid may flow gently down the reservoir inlet path 29 and may be collected in the reservoir 26 .
[0027] The outlet conduits 12 and 15 may extend through the top of the assembly rather than through the base as shown in FIG. 2 . Referring to FIG. 3 , an exemplary culture chamber 20 of the array is depicted with the inlet conduit 21 covered to allow the flow of fluid to move axially towards the center of chamber 20 and over dam 31 of outlet conduit 22 . The chamber 20 also affords a passage 24 for the egress of culture gasses collected and delivered to gas outlet conduit 14 , illustrated in FIG. 1 . Waste gasses that may be collected in the head space of the reservoir, may be collected and delivered via gas conduit 24 to the exit conduit 14 , illustrated in FIG. 1 .
[0028] A large surface area of culture chambers may be provided by the superpositioning of culture chambers 20 . Referring to FIG. 4 , the section removed reveals culture spaces 25 formed by the superpositioning of chambers 20 in an array. Fluids retained in the culture chambers 20 may cover the culture surfaces 25 . Referring to FIG. 5 , the culture surfaces may be structured 29 , illustrated in inset, to form either macro, micro or nano structures which may enhance the communication or distribution of nutrients or attachment sights within the culture chambers.
[0029] The exemplary embodiment discussed above is a cylindrical culture chamber device that combines certain fluid/gas delivery and mixing conditions. The embodiment discussed above may incorporate uniquely designed fluid/air dams, and sloped inlet structures to enhance the delivery of fluid medium and gasses to each of the culture chambers. The fluid dams and sloped inlets may deliver gentle, low shear, fluid to the culture chambers. The low shear mixing may be desirous for the culture of cells and many of the biochemicals and proteins that may be subject to degradation caused by shear or denaturizing. However is will be understood by one skilled in the art, that other configurations may be constructed to achieve the same effects of mixing. Referring to FIGS. 8 and 9 , the culture chambers 20 are illustrated with two different placements of the fluid inlet and outlet ports 11 and 12 .
[0030] In another exemplary embodiment, the chambers may be molded to form a structure that is self-contained and fluid tight. The structure may be rendered fluid tight via sealing, molding or welding the chambers together. It should also be appreciated however that it may be desirable to separate the chambers to harvest the cells or products therein. Accordingly, the chamber may be designed to seal upon superimposing the cell growth chambers.
[0031] According to one aspect of the invention, the cell culture device 10 may be provided as part of an assembly 100 as depicted schematically in reference to FIG. 7 . The assembly 100 may be constructed and arranged for continuous operation. The assembly 100 may be a closed loop system connecting the culture vessel 10 of the invention into a continuous culture system.
[0032] The fluid collected in reservoir 26 may be delivered via the fluid outlet conduit 12 to conduit 50 and to pump 60 . The pump 60 may move the fluid through conduit 51 to the fluid inlet conduit 11 . Fresh nutrients may be added via pump 70 and conduit 52 to the fluid circulation in conduit 51 . Excess nutrients-products/waste, may be collected by pump 71 via conduit 53 to maintain a constant volume of fluid within the vessel 10 . Optional sensors 92 may be employed to monitor the system. The sensors 92 may be connected to a control means 90 . The control means may have the ability to monitor or control the mixture of gasses delivered via conduit 54 to the gas inlet conduit 13 by controlling the gas mixture of gasses 80 , 81 and 82 at valves 95 , 96 and 97 . The control means may have the ability to control the fluid input 70 and output 71 pumps and the circulation pump 60 .
[0033] It should be understood that various changes and modifications of the embodiments described may be made within the scope of the invention. The foregoing description is provided to illustrate and explain the present invention. However, the description hereinabove should not be considered to limit the scope of the invention set forth in the claims appended here to.
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A multi-chamber cell culture assembly has provisions for the distribution of nutrient culture medium and gasses throughout each of the chambers. A device is constructed to provide a large surface area for the growth and cultivation of hybridomas, mammalian and insect cells. The device may incorporate macro, micro or nano structures on the growth surfaces to promote or enhance distribution of nutrients, cell product, gasses or growth area. Cell growth, nutrient addition and cell product withdrawal may be carried out automatically.
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FIELD OF THE INVENTION
This invention relates to thermoplastic or elastomer impregnated and lubricated wire ropes and more particularly to the reinforcing and filling of the thermoplastic or elastomeric material with discontinuous predispersed fibers, mineral fillers, or powders.
BACKGROUND OF THE INVENTION
The concept of reinforcing thermoplastic polymers or elastomers has produced an almost endless field of formulations. The most often used reinforcing polymer has been glass fiber, although higher performance fibers such as carbon and aramid have been gaining increased acceptance. Mineral reinforcements, although often regarded only as fillers or extenders, can improve certain properties of the base polymer. Reinforcers increase tensile strength when applied to a base resin and both reinforcers and fillers increase flexural modulus, with reinforcers offering greater increases. Impact properties in general will be increased by reinforcers. Both fillers and reinforcers will improve thermal properties, again with reinforcers offering greater increases.
Both reinforcers and fillers will lower the shrinkage of thermoplastics and elastomers thereby giving a more consistent material, however, reinforced thermoplastics shrink less in the direction of the flow than they do in the perpendicular direction. This property is termed anisotropic shrinkage.
It has been shown that there is minimum fiber length that would approach the degree of reinforcement afforded with a continuous system and yet not overly interfere with the moldability of the thermoplastic or elastomeric resin. One very important aspect of fiber size is the fact that laboratory tests of pressurized extrusion of a flexible thermoplastic between the outer strands of a rope have proven that for cross sections or wall thicknesses of the plastic that are less than 0.050 inch (1.27 mm) thick, "one dimension" reinforcement is approached because the thickness is less than the fiber length, creating forced alignment along the injection axis. Almost all the fibers are aligned in the flow direction giving 95% of the maximum reinforcement. This flow direction is perpendicular to the rope axis between the outer strands and then parallels said rope axis upon the plastic contacting the rope core. However, where wall thickness runs between 0.050 inch (1.27 mm) and 0.250 inch (6.35 mm) planar rather than one dimensional reinforcement is attained. This implies that half of the fibers are aligned in one direction and the other half are aligned in the perpendicular direction resulting in 50% of the maximum reinforcement obtained when all the fibers are aligned in direction of flow.
Tests on certain thermoplastics have shown that the tensile strength of the resin has been increased by more than 50% from 10,000 PSI to 16,000 PSI (704-1127 Kg/cm 2 ) by the addition of 5% fiberglass. Likewise, when the percent reinforcement has been increased to 5% or greater the Izod impact strength is increased by 50%; the flexural strength is increased by 22% and the flexural modulus is increased by 100%.
SUMMARY OF THE INVENTION
There are various types of plastic impregnated wire rope made for the purpose of improving fatigue life, reducing stresses, and inhibiting corrosion. Such ropes are disclosed in such U.S. Pat. Nos. as 3,824,777, 3,874,158 and 4,120,145. However, even greater benefits have been achieved by reinforcing the thermoplastic or reinforcing the elastomer with which the rope is impregnated.
The present invention provides a method for producing a well lubricated wire rope which is impregnated with a load bearing thermoplastic or elastomer such that the viscous lubricant is entrapped in the strands and core. The thermoplastic or elastomer is reinforced with discontinuous predispersed fibers, mineral filler or powders. Such mineral fillers and powders may include graphite or talcum. Further, the thermoplastic or elastomer may include a lubricating agent. The outside diameter of the plastic impregnated rope conforms to the outside diameter of the bare wire rope, or may extend beyond the outside diameter of the rope. The wire rope produced by this method usually has a smooth outer periphery with increased bearing area.
The present invention also provides a wire rope comprising a lubricated core including a central strand and a plurality of outer core strands wound therearound; a plurality of outer strands wound around said core, a flexible, reinforced thermoplastic resin or elastomer filling the spaces between the outer strands to retain the lubricant in the core and in the strands, wherein the outer diameter of the reinforced thermoplastic resin or elastomer conforms substantially to the outer diameter of the rope or beyond the outer diameter of the rope.
The present invention further provides a wire rope comprising a lubricated core including a central strand and a plurality of outer core strands wound therearound; a flexible reinforced thermoplastic or elastomer material filling the spaces between the outer core strands to retain the lubricant in the core, wherein the outer diameter of the reinforced thermoplastic or elastomer conforms substantially to the outer diameter of the core, and a plurality of strands wound around the core.
The plastic or elastomer impregnation of the wire rope of the present invention can be accomplished by pressurized extrusion of a flexible thermoplastic or elastomer into the interstices of the rope. During the pressurized extrusion, the fiber reinforcment or mineral filler is introduced at a concentration of 0 to 50% depending on the nature of the resin and the subsequent properties desired in the rope.
Impregnation of a lubricated wire rope with reinforced plastic or elastomer in accordance with the present invention significantly increases tensile strength of the wire rope, increases the flexural strength and flexural modulus of the wire rope, improves compression strength, inhibits entrance of foreign abrasive particles into the rope, prolongs the lubricant's life inside the rope and in addition forms a matrix that both supports and locks the individual strands in position relative to each other. The reinforced plastic or elastomer will permeate all of the spaces among the strands and the independent wire rope core will reduce the interstrand contact between the core and the outer strands and the mutual strand to strand contact. Furthermore, a well lubricated wire rope impregnated with reinforced plastic or elastomer while holding the outer strands spaced from each other, will have extremely good resistance to fatigue and an increased ultimate tensile strength because of the axial alignment of the fiber reinforcement and the reduction in internal strand contact, all while maintaining flexibility.
The present invention also provides for the addition of a powdered reinforcing agent to the plastic. The compressive strength of the plastic and thusly of the wire rope is increased by such addition.
The present invention further provides for the addition of a lubricating agent to the thermoplastic or elastomer. This lubricating agent will minimize internal friction, improve fatigue life and corrosion resistance for the wire rope.
It should be noted that the dimensions of the individual strands, the core, and the finished wire rope are the same as the corresponding dimensions of a standard rope without any coating. This is a very important consideration since most working ropes have to meet certain strength to size requirements as directed by machine/sheave configurations. Another advantage is a reduction in wire notching effect and internal friction because the load placed on the core strands are shared substantially equally by the spaced internal wires.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, FIG. 1 is a cross sectional view of one embodiment of the reinforced plastic or elastomer impregnated wire rope of the present invention;
FIG. 2 is a cross sectional view of a second embodiment of the reinforced plastic or elastomer impregnated wire rope of the present invention;
FIG. 3 is a cross sectional view of a third embodiment of the reinforced plastic or elastomer impregnated wire rope of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1 the present invention comprises a conventional wire rope 10 wherein individual wires 12 are wound into strands 14, and a plurality of strands are wound about a core 16 which is also preferably formed of a central strand 17 and a plurality of outer core strands 18. It should be understood that the central strand 17 or the core 16 may be formed of a fiber material such as hemp instead of metallic wires as indicated in the drawing.
The manner of fabricating such a lubricated wire rope involves the winding of strands about the core, and the application of a lubricant to the core and the strands. The lubricated wire rope is then preheated to a temperature in the range of 100° to 300° F. (38° to 148° C.).
A flexible thermoplastic or elastomer 22 reinforced with either fibers, mineral fillers or powders is preferably extruded under pressure in the range of about 1500 to 5000 PSI (105 to 352 Kg/cm 2 ) and while holding the strands 14 spaced from each other, into the interstices between the strands 16 of the rope, but not extending outwardly beyond the outer diametrical limits of the rope 10 as indicated at 26. The reinforced thermoplastic can be any of those capable of being extruded such as polypropylene, polyurethane, polyethylene, nylon, PVC or tetrafluoroethylene. The reinforced elastomer may include rubbers such as nitrile or butyl. The reinforcing fibers can be any metallic or nonmetallic fiber with an optimum fiber diameter of 0.0004 inch (0.01 mm) to 0.005 inch (0.127 mm). The filler or powders can be organic or inorganic, metallic or nonmetallic. Further, the thermoplastic or elastomer may include a lubricant.
A second embodiment of the wire rope of the present invention is shown in FIG. 2. A wire rope is shown wherein a central core strand 30 is surrounded by outer core strands 32. Central core strand 30 and outer core strands 32 usually are comprised of metallic wires, but may be comprised of fiber material. A flexible thermoplastic 34 reinforced with either fibers, mineral fillers or powders is preferably extruded about the core, and extends to the outer diametrical limits of the outer core strands 32. The plastic encapsulated core is then surrounded by outer strands, forming a wire rope.
A third embodiment of the wire rope of the present invention is shown in FIG. 3. A wire rope is shown wherein a central core 40 comprising individual strands 41 is surrounded by outer strands 42 comprising individual strands 43. Central core 40 and outer strands 42 usually are comprised of metallic wires, but may be comprised of fiber material. A flexible thermoplastic or elastomer 44 reinforced with either fiber, mineral fillers or powders is preferably extruded into the rope, and extends beyond the outer diametrical limits of outer strands 42.
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Reinforced thermoplastic impregnated lubricated wire ropes are provided in the present invention. A method of reinforcing and filling the thermoplastic material with fibers, mineral fillers and powders is also provided.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improvement of a call signal conversion apparatus for an elevator system.
2. Description of the Prior Arts
The elevator system equipped with digital apparatus such as a computer need to have floor buttons and car buttons and registration lamps which are connected with the buttons to turn-on by each calling and a signal conversion circuit for converting signal to a control device of the computer.
Heretofore, the signal conversion circuit usually comprises independently a signal conversion circuit for call buttons and a signal conversion circuit for registration lamps as shown in FIG. 1.
In FIG. 1, the reference numeral (1) designates a call button; (2) designates an elevator control device; (3) designates a call button signal conversion circuit; (4) designates a call registration lamp; and (5) designates a call registration lamp signal conversion circuit. The call button signal conversion circuit (3) comprises a detection circuit for detecting the call signal resulted by the actuation of the call button (1); a conversion circuit for converting the signal required for transmitting the detected signal to the control device (2); and a logic circuit for transmitting and controlling the call data to the control device (2) depending upon the desired data command time given by the control device (2). In the control device (2) receiving the data from the call button signal conversion circuit (3), the calling is memorized (registered) and a turn-on command is transmitted to the call registration lamp signal conversion circuit (5) so as to turn-on the corresponding call registration lamp (4). The signal conversion circuit (5) comprises a logic circuit which controls the turn-on of the call registration lamp (4) by receiving the command from the control device (2) and a driving circuit which is actuated by the logic circuit so as to turn-on the call registration lamp (4) by the output of the driving circuit.
As mentioned above, the conversion circuit (3) and the conversion circuit (5) are the separate circuits whereby they can be also utilized as the other device such as a relay driving circuit and a position indicator driving circuit. However, the number of the relays is reduced depending upon the development of the control device (2) with semiconductors, though many relays had been used. Moreover, only the signal conversion circuits for service floors are needed for the position indicators. Therefore, the ratio of the signal conversion circuits for calling in the elevator system has been increased. In the conventional apparatus, the signal conversion circuit (3) for the button (1) and the signal conversion circuit (5) for the call registration lamp (4) have been separately needed, to cause useless circuit equipments. The number of the print boards has been increased to cause high cost for the signal conversions.
As signal lines from the call buttons to the elevator control panel, one line is needed for detecting the calling and one line in needed for turning on the call registration lamp. Three kinds of callings as the car call, the floor uphall call and downhall call are given. Therefore, six signal lines are needed for one floor. The number of the lines is increased in proportional to the number of the elevator service floors, whereby the cost and processes for construction are disadvantageously increased.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the above-mentioned disadvantages and to provide a call signal conversion apparatus for an elevator system which has not useless equipments and is economical.
The foregoing and other objects of the present invention have been attained by providing a call signal conversion apparatus for an elevator system which comprises a call button device as a serial connection of a call button and a call registration lamp; a control device as a computer for inputting a call signal given by actuation of the call button, registering the calling and outputting the call registration signal; a signal conversion circuit connected between the button device and the control device wherein said signal conversion circuit comprises a call detection circuit for detecting the call signal; a waveform shaper circuit which shapes the call signal to output the signal to the control circuit; a memory circuit for memorizing the call signal or the call registration signal; and a driving circuit for outputting the signal for turning on or off the call registration lamp by detecting the output of the memory circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the conventional call signal conversion apparatus for an elevator system;
FIG. 2 is a block diagram of one embodiment of the call signal conversion apparatus for an elevator system according to the present invention;
FIG. 3 is a circuit diagram of the signal conversion circuit (7) in FIG. 2;
FIGS. 4 and 5 are graphs of signals at selected points of the circuit shown in FIG. 3; and
FIG. 6 is a block diagram of the other embodiment of the apparatus according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 2 to 5, one embodiment of the present invention will be illustrated.
In FIG. 2, the reference numeral (6) designates a call button device comprising one body of the call buttons (1) and the call registration lamps (4); (7) designates a signal conversion circuit comprising a call detection circuit (8), a waveform shaping circuit (9), a gate circuit (10), a memory circuit (11) and a driving circuit (12); (13) designates a common signal line for connecting the call button device (6) to the signal conversion circuit (7).
In FIG. 3, the reference numeral (14) designates a call terminal for connecting to the common signal line (13) shown in FIG. 2; (15) designates a power source terminal in high voltage side to connect to the positive side of the single phase full wave rectifying power source such as AC 100 V full wave rectifying power source; (16) designates an earthing terming in the high voltage circuit to connect to the negative side of the single phase full wave rectifying power source; (17) to (21) designate terminal groups for connecting to the control device (2) shown in FIG. 2; (22) and (23) respectively designate a power source terminal and an earthing terminal in the low voltage circuit and the power source terminal (22) is connected to the positive side of the DC power source (such as DC power source having 5 volt) (not shown) and the earthing terminal (23) is connected to the negative side of the DC power source; (8a) designates a photocoupling device comprising a photodiode (8a1) and a phototransistor (8a2) which detects the call button signal and insulates between the high voltage circuit and the low voltage circuit; (8b) designates a current limiting resistor for the photodiode (8a1); (8c) designates a diode for protection from inversion withstand voltage; (8d) designates a diode for preventing reverse current passing from the call terminal (14) to the power source terminal (15); (8e) designates a collector resistor for the phototransistor (8a2); (8f) designates a base resistor. An emitter earthing amplifying circuit is formed by the phototransistor (8a2), the collector resistor (8e) and the base resistor (8f). The reference numerals (9a), (9b) respectively designate resistors; (9c) designates a capacitor; (9d) designates a transistor; (9e) designates an inverter. The resistor (9a) and the capacitor (9c) form a CR filter circuit. The output of the filter circuit is amplified by the collector earthing amplifying circuit (emitter follower) comprising the transistor (9d) and the resistor (9b). The inverter (9e) causes the inversion of the logical level of the signal and the shaping of the signal for slow raising or falling time into the signal for fast raising and falling time signal. The reference numeral (10a) designates an NAND gate, and the output of the inverter (9e) is connected to one of the input terminal; and the other input is connected to the terminal (18) and the output is connected to the terminal (17), and the call data command timing signal is given from the control device (2) to the terminal (18). The reference numeral (11a) designates a flip-flop (1 bit memory) which comprises a data input terminal D, a timing input terminal T and a reset input terminal R which are respectively connected to the terminals (19) to (21) which are connected to the control device (2). The flip-flop (11a) is set(to turn-on the all registration lamp (4)) or reset (to turn-off the same) depending upon the data given to the data input terminal D under synchronizing to the timing signal given to the timing input terminal T. The signal for controlling all of the flip-flops (11a) for each calling to the reset state is applied to the reset input terminal R at the initiation such as the actuation of the power source of the elevator system. The reference numeral (11b) designates an inverter having a large output current capacity which amplifys the output (Q terminal) of the flip-flop (11a) to drive the driving circuit (12) connected to the next step. When the driving circuit (12) can be directly actuated by the flip-flop (11a), it is unnecessary to use the inverter (11b). In this case, the output signal given from the Q terminal is applied. The reference numeral (12a) designates a photocoupling device comprising a photodiode (12a1) and a phototransistor (12a2) which detects the call registration lamp signal and insulates between the high voltage circuit and the low voltage circuit; (12b) designates a current limiting resistor for the photodiode (12a1); (12c) designates a base resistor for the phototransistor (12a2) to stabilize the phototransistor (12a2). The reference numeral (12d) designates a thyristor for turning on the call registration lamp (4); (12e) designates a capacitor; (12f) designates a resistor which is needed for stable operation of the thyristor (12d); and (12g) and (12h) respectively collector voltage limiting resistors for the phototransistor (12a2) to have the function for controlling the gate current of the thyristor (12d); and (12i) designates a resistor; (12j) designates a capacitor; and the resistor (12i) and the capacitor (12j) form a CR surge absorber which has the function for stabilization of the operation and elimination of outer noise given through a call terminal (14).
Referring to FIGS. 4 and 5, the operation of the embodiment will be illustrated.
The single phase full wave rectifying voltage A is applied to the terminal (15).
The voltage B at the call terminal (14) is changed to be low level by pushing the call button (1) whereby the circuit of (15)-(8b)-(8a1)-(8d)-(14)-(13)-(1) is formed. In the state, the pulse current C passes through the photodiode (8a1) to the arrow direction depending upon the power source voltage A for the time T 1 pushing the call button (1). When the current C is larger than a desired current, the phototransistor (8a2) is in the saturating state whereby the collector voltage D of the phototransistor (8a2) is substantially zero. When the current C decreases, the phototransistor (8a2) changes into the active region to output the voltage in proportional to the current C . The transistor (9d) is turned on by the voltage D applied through the CR filter circuit and the output voltage E has the waveform for gradually raising or falling in the raising or falling of the voltage D . The output of the inverter (9e) i.e. the output of the waveform shaping circuit (9) inverts the waveform of the voltage D and gives the waveform for faster raising time and falling time. Thus, when the call signal is applied to the input terminal of the NAND gate (10a) after the period T 2 from the turn-on of the call button (1) and the call button (1) is turned off, the off state is transmitted after the period T 3 .
On the other hand, when the call data are required, the data requirement timing signal G is transmitted from the control device (2) as shown in G 1 in the ON state of the call button (1) and G 2 in the OFF state of the call button (1). The output voltage H of the NAND gate gives "L" level only in the ON state of the call button (1) to transmit the call signal through the terminal (17) to the control device (2).
When the control device (2) registers the calling by the output H of the gate circuit (10), the call registration signal I inputs to the terminal (19). The signal is the turn-on signal for the call registration lamp (4) in "H" level of the data signal whereas it is the turn-off signal in "L" level of the data signal. The reference J designates a timing signal. The memory device (11a) is set by the timing signal J 1 to give the output K in "H" level. The memory device (11a) is reset by the timing signal J 2 to give the output K in "L" level. The output L of the inverter (11b) has reverse polarity to the output K . When the memory device (11) is set to give the output L in "L" level, the photocoupling device (12a) is actuated to turn-on the thyristor (12d) by the output. The call registration lamp (4) is turned on by the circuit of (15)-(4)-(13)-(14)-(12d)-(16). The voltage B at the call terminal (14) and the current C of the photodiode (8a1) have slightly different waveforms as shown in FIG. 5 from the waveforms shown in FIG. 4. The phenomenon is caused by the actuation of the thyristor (12d) by the waveform of the power source voltage A . During the turn-on of the call registration lamp (4), the thyristor (12d) is repeatedly turned on and off.
Thus, the call registration lamp (4) is turned on by pushing the call button (1) and the signal equivalent to the pushing of the call button (1) is simultaneously transmitted through the call detection circuit (8) to the control device (2).
The call signal is transmitted through the cable connecting the control device (2) equipped in an elevator machine room to the call buttons (1) equipped in the car or the hall whereby certain effect of outer noise is easily given. The outer noise, however, can be eliminated by the filter function of the waveform shaping circuit (9) as one of the elements of the signal conversion circuit (7). Therefore, it is unnecessary to connect a special circuit for preventing the noise.
FIG. 6 shows the other embodiment of the present invention.
The elements of the embodiment shown in FIG. 6 have equivalent functions to those of the elements shown in FIG. 2 and accordingly, the description of these elements is not repeated. The different structure from the embodiment shown in FIG. 2 is to actuate the memory circuit (11) directly by the output of the wave-form shaping circuit (9). The memory circuit (11) is set by pushing the call button (1) to actuate the driving circuit (12) without using the control device (2) to turn-on the call registration lamp (4). In the control device (2) of this embodiment, the call data read-in function is the same as that of FIG. 2, however, it outputs the reset signal to the memory circuit (11) only when the call registration lamp (4) is turned off whereby the memory circuit (11) is reset to turn-off the call registration lamp (4).
As the memory circuit (11), the memory circuit for setting or resetting under synchronizing to the timing signal, is used in the embodiment shown in FIG. 3, whereas the memory circuit for setting by raising or falling change of the signal is used in the embodiment shown in FIG. 5.
In these embodiments, the circuit for only one calling is shown. In the practical system, n circuits in parallel are needed for n callings. In these embodiments, the transistor circuit of the call detection circuit (8) is the emitter earthing amplifying circuit, however, it can be a collector earthing amplifying circuit. As the amplifying circuit of the waveform shaping circuit (9), the collector earthing amplifying circuit can be an emitter earthing amplifying circuit.
The memory circuit (11) is formed by the D flip-flop having the D and T terminals, however, a memory circuit having the other circuit element such as RS flip-flop or JK flip-flop can be used.
The thyristor is used in the driving circuit (12), however, the other semiconductor device such as a two way thyristor and a transistor or a mechanical part such as a relay can be used for the driving circuit (12). The photocoupler element (8a) is used for the insulation of the high voltage circuit from the low voltage circuit, however, it is possible to receive directly by the transistor in the case of the call detection circuit (8) and it is possible to actuate the driving circuit (12) directly by the output of the IC circuit.
An inversion signal can be also used as the signal between the signal conversion circuit (7) and the control device (2) beside the signals shown in FIGS. 4 and 5. This can be easily given by the addition of an inverter or the formation of the NAND gate by an AND gate. It is also easy to add a circuit for using the timing signal as a codified signal and decoding to the signal conversion circuit (7).
As described above, in accordance with the present invention, the signal conversion circuit connected between the call button device and the control circuit is formed by the call detection circuit for detecting the call signal; the waveform shaping circuit for shaping the call signal; the memory circuit for memorizing the call registration signal and the driving circuit for turning on and off the call registration lamp by the output of the memory circuit, whereby the functional elements required for the transmission and receiving of the signal can be combined into one to improve the density of equipped elements on the print wiring boards and to reduce the number of the print wiring boards and to reduce the cost for the signal conversion circuit.
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A call signal conversion apparatus for an elevator system comprises a call button device as a serial connection of a call button and a call registration lamp; a control device as a computer for inputting a call signal given by actuation of the call button, registering the calling and outputting the call registration signal; and a signal conversion circuit connected between the button device and the control device. The signal conversion circuit comprises a call detection circuit for detecting the call signal; a waveform shaper circuit which shapes the call signal to output the signal to the control circuit; a memory circuit for memorizing the call signal or the call registration signal; and a driving circuit for outputting the signal for turning on or off the call registration lamp by detecting the output of the memory circuit.
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BACKGROUND OF THE INVENTION
1. Field of the Invention.
In regenerative heat exchange apparatus, a mass of heat absorbent material commonly comprised of packed element plates that form a heat absorbent matrix is positioned in a hot gas passageway to absorb heat from hot gases passing therethrough. After the plates become heated by the hot gas they are moved into a passageway for cool air where the heated plates transfer their absorbed heat to the cool air flowing therethrough.
As the hot exhaust gases are directed through the heat exchange apparatus, fly ash and unburned products of combustion carried by the exhaust gases are deposited on the surface of the packed element plates, and such deposits continue to be deposited and build up until air and gas flow through the heat exchanger are greatly retarded, if not substantially stopped. Heat is then generated in the deposits and the adjoining element to form a "hot spot" that, if not detected, will rapidly increase until the adjoining metal of the heat exchanger will itself ignite and cause a catastrophic fire.
2. Description of the Prior Art.
Recent developments in the use of infra-red ray detection apparatus to detect "hot spots" in a heat absorbent matrix of an air preheater in the manner disclosed by U.S. Pat. No. 3,861,458 of 1975 and U.S. Pat. No. 3,730,259 of 1973 have been extremely successful in carrying out their stated objective of signaling a potential "hot spot" or incipient fire well in advance of the occurrence of an actual damaging fire.
A subsequent U.S. Pat. No. 4,022,270 of 1977 was granted to define a series of detector "heads" that were moved in unison on independent lever arms to a position where they might "view" the potential "hot spots" and provide a signal that could be monitored by an operator. The detector heads were adapted to simultaneously move on arcuately movable arms to scan the heat absorbent matrix and then move back to an air lock where they could readily be cleaned or repaired for subsequent operation.
Frequently, however, lever arms supporting the detector heads would be slightly deformed or even radically bent so that they would fail to completely seat on the air lock while others would make a satisfactory seat in the manner originally proposed. Thus fly ash and unburned combustion products would continuously collect in some of the air locks not properly sealed, while further opening of an air lock door would create a flow passageway through the air lock permitting pressurized fluid from inside the heat exchanger to flow to the atmosphere.
SUMMARY OF THE INVENTION
This invention therefore relates to an arrangement for adjusting each radially swinging fire detector head independently and the chief objective is to provide an arrangement for adjusting each fire detection head independently of all other elements of the system by the use of an articulated lever arm having an adjusting means integral therewith.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a rotary regenerative heat exchanger that includes the apparatus of the invention,
FIG. 2 is an enlarged top plan of an assembly of infrared ray detectors,
FIG. 3 is an enlarged top plan view showing a specific adjusting means, and
FIG. 4 is an enlarged cross-section of an adjustable lever arm as seen from line 4--4 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawing a rotary regenerative air preheater comprises a cylindrical housing 10 that encloses a rotor having a casing 14 divided into a series of sectorial compartments by radial partitions 16 that extend between the casing 14 and a central rotor post 15. The compartments each contain a mass of heat absorbent material 17 in the form of corrugated plates or the like that provide passageways for the flow of fluid between opposite ends thereof. The rotor is rotated slowly about its axis by a motor 20 that advances the heat absorbent element contained by the rotor compartments and positions it alternately between the heating fluid and the fluid to be heated so that the heat absorbent material may absorb heat from the heating fluid and give it up to the fluid to be heated. After passing over the heated material and absorbing heat therefrom, the heated fluid is discharged through duct 32 to a boiler furnace or other place of use.
During start-up of a boiler furnace or other apparatus from which a heat exchanger receives a flow of hot exhaust gases, incomplete combustion of fuel in the burners thereof may cause particles of unburned fuel and products of combustion to become entrained in gases exhausting therefrom so that they tend to be deposited upon the heat absorbent matrix of the heat exchanger. These deposits accumulate rapidly and in a short time partially or even completely block the flow of the heating fluid and the fluid to be heated. Inasmuch as these surfaces are not then subjected to a cooling air flow, they continue to increase in temperature until a temperature of 700° F. to 750° F. is achieved. At this point the process becomes self-sustaining and heat is generated within the deposits until an active fire occurs, often with disastrous results.
Detectors that monitor apparatus of the type defined have been developed in accordance with U.S. Pat. No. 4,022,270. In this patent a series of detector heads 36 responsive to infra-red rays is positioned at the end of lever arms 38. The lever arms are themselves pivotally mounted in a gear box 42 at the side of rotor housing such that they swing in unison and together face the rotor and then, as the rotor rotates, the arms 38 swing back until the detector heads seat on the enclosure 40.
The detector heads on lever arms 38 are pivotally moved by gears 45 in box 42 mounted on the side of the rotor housing. An actuating arm or lever 46 extends back from each gear box and is pivotally attached at 48 to a reciprocating linkage 52, the reciprocating linkage being moved forward and backward by any suitable prime mover 55. As the linkage 52 is moved, the lever 46 rotates the gears 45 in gear box 42 and the lever arm 38 is moved arcuately outward to expose each detector head 36 to the potential emission of infra-red rays, but when the lever arms 46 are moved oppositely they move to a position where they seat upon the enclosure 40. Each enclosure has a removable door 62 as the outer wall thereof adapted to cover the opening 54 in the housing wall 35, while a sealing ring 58 around the opening in the enclosure precludes the flow of fluid when the detector head seats tightly thereto.
When a detector is exposed to the heating fluid, it is simultaneously subjected to contaminants carried by such fluid so that it becomes clouded, its sensitivity is reduced, and it must be cleaned to maintain its efficiency. When cleaning a detector head 36 becomes necessary, the heads are all swung toward the housing wall until they each seat over the respective opening of an aligned enclosure 40. Due to variations in structure, temperature, or operating conditions, all detector heads will not seat simultaneously, so while the seating of one head on enclosure 40 may prevent contaminants from flowing out from one enclosure, a leakage path may exist at other air lock enclosures 40 and leakage into the enclosure will occur. Further removal of a door 62 covering an opening in the side of enclosure 40 will permit fluid and its contaminants to flow out of enclosure 40 and contaminate the ambient atmosphere.
According to this invention each lever arm 46 is provided with a lateral adjusting means whereby the angle of throw of each lever may be varied to move the gears 45 in gear box 42 and lever arm 38 whereby each head 44 enclosing detectors 36 may be made to seat in a fluid-tight relationship over the opening in enclosure 40 to preclude fluid flow therethrough.
The adjusting means comprises a sleeve 63 keyed to shaft 64 and adapted to extend axially through one of gears 45. The sleeve has a projection 66 on one side thereof that extends loosely into a space 68 between spaced extensions 72 at an end of arm 46. In order that the projection 66 may be held tightly in space 68, each extension 74 is drilled and tapped to receive an adjusting screw 76. By loosening one screw 76 and tightening the opposed screw, the position of the projection 66 may be varied relative to the notch 68, and the gear train 45 rotated sufficiently to move the arm 38 and head 44 arcuately to obtain a perfect seating.
The shaft 64 from gear means 45 extends axially therefrom, through suitable sealing means in box 42 to preclude leakage between opposite sides thereof. Inasmuch as the lever 46 is completely outside housing 42, it is readily available for servicing or adjustment during normal operation. Should conditions be varied sufficient to effect an improper seating of a head 44 upon the enclosure 40, it is only necessry to adjust the particular screws 76 that control the "throw" of the particular lever being affected, and that head only will be moved arcuately forward or backward until proper seating is assured and a leak-free arrangement is maintained.
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A fire detection system for rotary regenerative heat exchange apparatus having multiple detectors, each detector being mounted independently on an arcuately reciprocable scanning arm. The several arms are laterally adjustable by a system of opposed screws in an articulated yoke to permit the selective positioning of each arm independent from the other scanning arms of the system.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of application Ser. No. 11/411,874, filed Apr. 27, 2006, (which issued as U.S. Pat. No. 7,908,698 on Mar. 22, 2011) which claims priority of Japanese Patent Application No. 2006-008323, filed on Jan. 17, 2006, the entire contents of which are incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cleaning apparatus and a cleaning method for a wafer preferable for manufacturing a semiconductor device.
2. Description of the Related Art
Recently, in a manufacturing process of a semiconductor device, it is becoming essential to planarize a film or the like having been formed by that time by performing a CMP (Chemical Mechanical Polishing) processing before a photolithography, in order to secure an exposure margin for the photolithography. Here, a method of planarization by the CMP processing will be described with reference to FIG. 10 . FIG. 10 is a schematic view showing an outline of a CMP apparatus.
The CMP apparatus is provided with a polishing table 51 on a surface of which a polishing pad 52 is affixed, a polishing head 54 holding a wafer 53 , and a slurry supplying nozzle 55 supplying slurry (suspension containing a grain of abrasive) 56 . Further, the CMP apparatus is provided with a dressing apparatus 57 dressing the polishing pad 52 . The polishing table 51 and the polishing pad 52 are rotatable around their own axes.
In a CMP processing using the CMP apparatus with such a constitution, the slurry 56 is supplied from the slurry supplying nozzle 55 onto the polishing pad 52 while the polishing table 51 is being rotated, and the wafer 53 is pressed on the polishing pad 52 while the polishing head 54 is being rotated. As a consequence, the wafer 53 is polished by the polishing pad 52 . To a portion of the polishing pad 52 which is squashed due to the wafer 53 being pressed on, a dressing is performed by the dressing apparatus 57 during rotation.
The CMP processing is performed as above, and the abrasive grain contained in the slurry, metal impurity, or the like remain on the wafer 53 after the CMP processing. Thus, a cleaning of the wafer 53 is required after the CMP processing. Here, a conventional cleaning method of a wafer will be described with reference to FIG. 11 and FIG. 12 . FIG. 11 is a perspective view showing a conventional cleaning apparatus, while FIG. 12 is a front view showing the conventional cleaning apparatus.
The conventional cleaning apparatus is provided with two cylindrical brushes 63 contacting a front surface and a rear surface of the wafer 53 , respectively. The brush 63 is made of synthetic resin and a plurality of projections are formed on a surface thereof. Additionally, a shaft 62 is inserted into the brush 63 . In a cleaning using this apparatus, the brushes 63 and the wafer 53 are rotated while the two brushes 63 are made to contact the front surface and the rear surface of the wafer 53 .
It is also carried out that a plurality of such cleaning apparatuses are provided to perform cleanings using different cleaning solutions. For example, after a cleaning is performed with an ammonia solution being supplied, another cleaning may be performed with a fluorinate acid being supplied. By this method, the abrasive grain is removed by the cleaning using the ammonia solution and the metal impurity is removed by the cleaning using the fluorinated acid.
By these methods, a sufficient cleaning is possible for a wafer with a diameter of 200 mm or less. However, when the cleaning is performed for a wafer with a diameter of about 300 mm according to the above-described method, numerous foreign objects 58 remain on an outer peripheral portion of the wafer 53 as shown in FIG. 13 . This is considered because times during which a central portion and the peripheral portion of the wafer 53 contact the brush 63 are different. That is, in the peripheral portion, time during which the wafer is apart from the brush 63 is relatively long and a cleaning efficiency is deteriorated.
Thus, there is disclosed an art in which a brush having larger diameters in both ends is used to increase the cleaning efficiency in the outer peripheral portion (Patent Document 1).
However, using the brush having the larger diameters in the both ends is not practical. This is because a variation of the diameter of the brush must be adjusted in response to the diameter of the wafer. Moreover, since a direction and an amount of a warp of the wafer vary in response to a kind, a number, and a pattern and the like of films already formed, it is required to prepare more various brushes in order to correspond also thereto.
For example, in such a case as after a CMP processing for forming an element isolation region by STI (Shallow Trench Isolation), the wafer 53 is warped into a shape of a mound as shown in FIG. 14A . As a result, on the front surface of the wafer 53 the outer peripheral portion is hard to contact the brush 63 . On the other hand, in such a case as after a CMP processing for forming a metal wiring, the wafer 53 warps into a shape of a bowl as shown in FIG. 14B . As a result, on the front surface of the wafer 53 the outer peripheral portion is easy to contact the brush 63 , while on the rear surface the outer peripheral portion is hard to contact the brush 63 . Therefore, unless brushes of a plurality of kinds are prepared for the same wafer, foreign objects on the front surface and the rear surface of the wafer 53 cannot be removed sufficiently. Additionally, not only the direction of the warp but also the amount of the warp varies in response to a film forming condition or the like as described above.
As described above, in the conventional method in which the brush with the varied diameter is used, it is required to prepare various brushes, resulting in a higher cost.
Though it is possible to remove the foreign objects using conventional brushes if the cleaning is performed for a long period of time, a time period of at least about three to four times of a time period required for the cleaning of the wafer with the diameter of about 200 mm is necessary. As a result, a throughput is substantially decreased.
Related arts are disclosed in Patent Document 1 (Japanese Patent Application Laid-open No. 2003-163196) and in Non-patent Document 1 (Clean Technology VOL. 8, No. 5 (May 1998)).
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a cleaning apparatus and cleaning method for a wafer which are capable of reliably cleaning various wafers without using various kinds of brushes.
In order to solve the above problem, the present inventor has devised embodiments of the present invention described below as a result of acute study.
A cleaning apparatus for the wafer according to the present invention is provided with a straight-shaped front surface cleaning brush contacting a front surface of the wafer, and a pressurizer enlarging diameters in both end portions of the front surface cleaning brush by means of applying a pressure on the front surface cleaning brush from both ends.
In a cleaning method for the wafer according to the present invention, a straight-shaped front surface cleaning brush is made to contact a surface of the wafer, and diameters in both end portions of the front surface cleaning brush is enlarged by means of applying a pressure on the front surface cleaning brush from both ends.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a top view showing a cleaning apparatus for a wafer according to a first embodiment of the present invention;
FIG. 1B is a front view showing the cleaning apparatus for a wafer according to the first embodiment of the present invention;
FIG. 1C is a side view showing the cleaning apparatus for a wafer according to the first embodiment of the present invention;
FIG. 2 is a view showing a brush 3 ;
FIG. 3 is a view showing a cleaning system for a wafer;
FIG. 4 is a view showing an operation of the first embodiment of the present invention;
FIG. 5 is a view showing a result of an observation (in a case in which a pressurizing is performed) actually carried out;
FIG. 6 is a view showing a result of the observation (in a case in which the pressurizing is not performed) actually carried out;
FIG. 7 is a front view showing a cleaning apparatus for a wafer according to a second embodiment of the present invention;
FIG. 8A is a view showing a shaft 12 ;
FIG. 8B is a view showing a cross section along a line I-I in FIG. 8A and a stopper 11 ;
FIG. 9 is a view showing an operation of the second embodiment of the present invention;
FIG. 10 is a view showing a planarization method by a CMP processing;
FIG. 11 is a perspective view showing a conventional cleaning apparatus;
FIG. 12 is a front view showing the conventional cleaning apparatus;
FIG. 13 is a view showing a result of a cleaning using the conventional cleaning apparatus;
FIG. 14A is a view showing a problem in a conventional cleaning method; and
FIG. 14B is a view showing a problem in the conventional cleaning method as well.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, embodiments of the present invention will be described concretely with reference to the attached drawings.
First Embodiment
To begin with, a first embodiment of the present invention will be described. FIG. 1A is a top view showing a cleaning apparatus for a wafer according to the first embodiment of the present invention. FIG. 1B is a front view showing the cleaning apparatus for the wafer according to the first embodiment of the present invention. FIG. 1C is a side view showing the cleaning apparatus for the wafer according to the first embodiment of the present invention.
In the first embodiment, there are provided a cylindrical front surface cleaning brush 3 a and a cylindrical rear surface cleaning brush 3 b which contact a front surface and a rear surface of a wafer 21 respectively, as shown in FIG. 1A to FIG. 1C . Hereinafter, the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b may be referred to generically as brushes 3 . The brushes 3 are made of synthetic resin such as PVA (Poly Vinyl Alcohol), for example, on surfaces of which a plurality of projections are formed as shown in FIG. 2 . A diameter of the projection is, for example, about 5 mm. Shafts 2 are inserted to the brushes 3 . Each brush 3 can be rotated with the shaft 2 being an axis. Additionally, rollers 4 rotating the wafer 21 are provided. Further, there are disposed a pure water nozzle 5 a spraying a pure water to the front surface of the wafer 21 , a pure water nozzle 5 b spraying a pure water to the rear surface, a chemical nozzle 6 a spraying a chemical solution (cleaning agent) to the front surface, and a chemical nozzle 6 b spraying a chemical solution (cleaning agent) to the rear surface. Incidentally, instead of using these nozzles, a communication path for liquid may be provided inside the brush 3 so that the pure water and the chemical solution are supplied from inside the brush 3 .
Further, in the present embodiment, along a direction in which the shaft 2 extends, there are provided pressure portions 1 which apply pressures on the brush 3 from both ends thereof. The pressure portion 1 is constituted using a pressure mechanism by a diaphragm system, for example. When the pressure portions 1 apply the pressures on the brush 3 , both side portions of the brush 3 are compressed and the diameters thereof become large in the both end portions.
In a cleaning system including the cleaning apparatus according to the first embodiment, as shown in FIG. 3 for example, there are provided a first brush unit 11 and a second brush unit 12 which include the cleaning apparatuses respectively, and further, a cleaning/drying unit 13 is provided in a subsequent step. In the first brush unit 11 , a cleaning agent of alkali or the like which is capable of removing abrasive grain is sprayed from the nozzles 5 a and 5 b . On the other hand, in the second brush unit 12 , a cleaning agent of acid or the like which is capable of removing metal impurity is sprayed from the nozzles 5 a and 5 b . For example, an ammonia solution is sprayed from the nozzles 5 a and 5 b of the first brush unit 11 , while a hydrofluoric acid is sprayed from the nozzles 5 a and 5 b of the second brush unit 12 . Additionally, in the cleaning/drying unit 13 , a pure water is supplied to rinse the wafer 21 while the wafer 21 is being rotated, and a drying is performed by high-speed rotation.
Here, a cleaning method using the cleaning system constituted as above will be described.
First, the wafer 21 on which the CMP processing is completed is conveyed to the first brush unit 11 , and the wafer 21 is held by the rollers 4 . Next, the wafer 21 is rotated by rotating the rollers 4 . Rotation speed at this time is not specifically limited, but is 50 rotations per minute, for example. Next, while the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are being rotated, they are made to contact both surfaces of the wafer 21 . Rotation speed at this time is not specifically limited, but is 200 rotations per minute, for example.
Incidentally, it is preferable that the pure water is supplied to the wafer 21 from the pure water nozzles 5 a and 5 b during the period from a holding of the wafer 21 by the rollers 4 to startings of the rotation of the wafer 21 and the rotation of the brush 3 so that the wafer 21 does not become dry.
After the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are made to contact the wafer 21 , the both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are deformed by means of pressurizing the both ends of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b by the pressure portions 1 . That is, the both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are compressed so that the diameters in the both end portions are enlarged as shown in FIG. 4 . As a consequence, the entire front surface of the wafer 21 is made to contact the front surface cleaning brush 3 a substantially evenly, even if the wafer 21 is warped into a shape of a mound. Therefore, a cleaning efficiency of the outer peripheral portion of the wafer 21 improves. Incidentally, a magnitude of the pressure applied by the pressure portions 1 is not specifically limited, but is about 0.1 kgw/cm 2 , for example.
While the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are being rotated in contact with the wafer 21 , an alkaline chemical solution is supplied to the wafer 21 from the chemical nozzles 6 a and 6 b . A composition of the alkaline chemical solution is not specifically limited, but an ammonia solution of about 0.5 weight percent, for example, is used. Also, supplying time is not specifically limited, but is about 30 seconds, for example.
The foreign objects such as abrasive grain on the front surface and the rear surface of the wafer 21 are removed by means of such rotation, pressurizing, and supplying of the chemical solution.
After a brush cleaning is performed for a predetermined time, the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are separated from the wafer 21 and the rotation is halted. Then, the pure water is supplied to the wafer 21 from the pure water nozzles 5 a and 5 b to rinse the front surface and the rear surface of the wafer 21 .
Subsequently, the wafer 21 is conveyed to the second brush unit 12 and the wafer 21 is held by the rollers 4 . Next, the wafer 21 is rotated by rotating the rollers 4 . Rotation speed at this time is not specifically limited, but is 50 rotations per minute, for example.
Next, an acid chemical solution is supplied to the wafer 21 from the chemical nozzles 6 a and 6 b . A composition of the acid chemical solution is not specifically limited, but a hydrofluoric acid of about 0.5 weight percent, for example, is used. Also, supplying time is not specifically limited, but is about 10 seconds, for example.
Incidentally, during the cleaning using the acid chemical solution, the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b may be made to contact the both surfaces of the wafer 21 while being rotated, similarly to the brush cleaning in the first brush unit 11 . Rotation speed at this time is not specifically limited, but is 200 rotations per minute, for example. It is preferable that the pure water is supplied to the wafer 21 from the pure water nozzles 5 a and 5 b during the period from a holding of the wafer 21 by the rollers 4 to startings of the rotation of the wafer 21 and the rotation of the brush 3 so that the wafer 21 does not become dry.
Further, after the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are made to contact the wafer 21 , the both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are deformed by means of pressurizing the both ends of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b by the pressure portions 1 , similarly to the brush cleaning in the first brush unit 11 . That is, the both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are compressed so that the diameters in the both end portions are enlarged as shown in FIG. 4 . Incidentally, a magnitude of the pressure applied by the pressure portions 1 is not specifically limited, but is about 0.1 kgw/cm 2 , for example. The pressurizing may be started during the period in which the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are being moved to contact the wafer 21 . That is, timing to start the pressurizing is not limited to after the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are made to contact the wafer 21 .
After the cleaning for a predetermined time using the acid chemical solution, supplying of the acid from the nozzles 6 a and 6 b is stopped. Then, the pure water is supplied to the wafer 21 from the pure water nozzles 5 a and 5 b , to rinse the front surface and the rear surface of the wafer 21 .
Subsequently, the wafer 21 is conveyed to the cleaning/drying unit 13 and the wafer 21 is mounted on a rotatable stage. Then, the wafer 21 is rinsed with a pure water while being rotated at high speed. Subsequently, the wafer 21 is dried.
According to such a cleaning method using the cleaning apparatus according to the first embodiment, at the time of the brush cleaning, the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are compressed and deformed to become easy to contact the outer peripheral portion of the wafer 21 . Therefore, a high cleaning efficiency is achieved. Additionally, since conventional brushes can be used as the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b , a cost increase can also be suppressed.
Here, results of an observation actually carried out by the present inventor will be described. In this observation, an oxide film of 500 nm in thickness is formed on a silicon wafer. Then, the oxide film is polished to be 250 nm by a CMP processing and a foreign object (defect) on a wafer surface is measured using a wafer surface examining apparatus (LS6800 of Hitachi High-Technologies Corporation). The result of a case in which both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are pressurized is shown in FIG. 5 while the result of a case in which the both end portions are not pressurized is shown in FIG. 6 .
As shown in FIG. 6 , when the both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are not pressurized, numerous foreign objects 22 exist in the outer peripheral portion of the wafer 21 . On the other hand, as shown in FIG. 5 , when the both end portions of the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b are pressurized, the foreign objects 22 scarcely exist over the entire surface of the wafer 21 .
Incidentally, the pressures applied on the front surface cleaning brush 3 a and the rear surface cleaning brush 3 b by the pressure portions 1 may be differentiated from each other. For example, as shown in FIG. 4 , when the wafer 21 is warped into the shape of the mound, the pressure applied on the rear surface cleaning brush 3 b may be smaller than the pressure applied on the front surface cleaning brush 3 a , or only the front surface cleaning brush 3 a may be compressed. In contrast, when the wafer 21 is warped into a shape of a bowl, the pressure applied on the front surface cleaning brush 3 a may be smaller than the pressure applied on the rear surface cleaning brush 3 b , or only the rear surface cleaning brush 3 b may be compressed.
Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 7 is a front view showing a cleaning apparatus for a wafer according to the second embodiment of the present invention.
In the second embodiment, a front surface cleaning brush 13 a is constituted with three front surface cleaning brush pieces 13 a - 1 , 13 a - 2 and 13 a - 3 as shown in FIG. 7 . Also, a rear surface cleaning brush 13 b is constituted with three rear surface cleaning brush pieces 13 b - 1 , 13 b - 2 and 13 b - 3 . These brush pieces are made of synthetic resin such as PVA (Poly Vinyl Alcohol), for example, on surfaces of which a plurality of projections are formed. One shaft 12 is inserted to the three front surface cleaning brush pieces 13 a - 1 , 13 a - 2 and 13 a - 3 , while one shaft 12 is inserted to the three rear surface cleaning brush pieces 13 b - 1 , 13 b - 2 and 13 b - 3 . Cut-outs 14 are formed on two locations of the shaft 12 as shown in FIG. 8A and FIG. 8B . To the cut-outs 14 , disk-shaped stoppers 11 are fixed. A diameter of the stopper 11 is, for example, larger than a diameter of the shaft 12 by about 5 mm to 10 mm.
The other constitution is the same as that of the first embodiment.
In the second embodiment as above, when both ends of the front surface cleaning brush 13 a and the rear surface cleaning brush 13 b are pressurized by the pressure portions 1 , as shown in FIG. 9 , only the front surface cleaning brush pieces 13 a - 1 and 13 a - 3 and the rear surface cleaning brush pieces 13 b - 1 and 13 b - 3 , which are located on the both ends, are compressed, and the diameters thereof become large. As a consequence, the entire front surface of the wafer 21 is made to contact the front surface cleaning brush 13 a substantially evenly, even if the wafer 21 is warped into a shape of a mound. Therefore, a cleaning efficiency of the outer peripheral portion of the wafer 21 improves. Additionally, compared with the first embodiment, the cleaning efficiency is higher since deformations concentrate in the portions contacting the outer peripheral portion of the wafer 21 .
In the second embodiment, if the brush piece is required to be exchanged, it is only necessary to detach the stopper 11 . Therefore, it is possible to easily cope with various kinds of warp directions and warp amounts of the wafer by using a conventional brush whose diameter is uniform in a longitudinal direction as the brush piece and combining them.
Incidentally, in the first and the second embodiments, the constitution in which the cleaning is performed with the wafer 21 being kept horizontal is adopted, but a constitution in which the cleaning is performed with the wafer 21 being kept vertical may be adopted. Also, an ultra sonic cleaning unit may be provided in a prior step of a brushing, or in the cleaning/drying unit.
According to the present invention, since the diameters of the both end portions of the front surface cleaning brush is enlarged by the application of the pressure, the front surface cleaning brush can be made evenly contact the entire front surface of the wafer even if the wafer is warped. Consequently, a high cleaning efficiency can be achieved even without using various kinds of brushes, so that cleaning of various wafers can be performed reliably.
The present embodiments are to be considered in all respects as illustrative and no restrictive, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.
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A front surface of the wafer is contacted with a straight-shaped front surface cleaning brush, and a pressure is applied on the front surface cleaning brush from both ends to enlarge the diameters in both end portions of the front surface cleaning brush. The front surface cleaning brush rotates with a shaft being an axis. An inner surface of the front surface cleaning brush is directly in contact with a surface of the shaft. The front surface cleaning brush is composed of a single structure made of synthetic resin.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a Continuation of and claims the benefit of priority to the U.S. Non-provisional application having Ser. No. 10/919,623, titled “Play Swing Systems and Methods of Play”, filed on Aug. 17, 2004. The present application also claims the benefit of priority to the U.S. provisional application having Ser. No. 60/498,216, titled “Play Swing Systems and Methods of Play”, filed on Aug. 26, 2003, both of which are incorporated herein by reference.
BACKGROUND OF INVENTION
The present invention relates to play swings, including play and safety accessories for use therewith.
Although swings are a favorite play pastime of young children, they are rather quickly out grown, in the sense that older children lose interest. It is therefore a first object of the present invention to provide additional play activities for play swings. Yet another objective is to provide interactive and competitive play activity. In particular, a further objective is to provide for the safe conduct of activities that develop the coordination of spatial perception, dexterity and reflexes
SUMMARY OF INVENTION
In the present invention, the first object is achieved by providing a swing seat, for suspension and oscillatory motion from a horizontal support, various accessible toys, games or amusements that are coupled or otherwise associated with the seat or supporting structure in a cooperative arrangement. Such games and amusements may includes a variety of interactive targets that are independent of the play structure, or attached to a fixed or oscillatory component of the play structure, such as a container, bin or basket for receiving an object thrown by a player in the swing seat.
Further embodiments of the swing seat may include a harness for restraining the forward motion of a player out of the seat, depending on the nature of the play or game activity.
A second aspect of the invention is characterized in that the seat, swing system or both in combination includes a variety of water related play attachments that enable games or simply provide relief from hot and humid weather.
In yet another aspect of the invention the play system and methods include the use of game targets and projectiles while swinging. Manipulation of same can be used to control a water source, via an actuator responsive to movement of the target on impact with a projectile, or the accumulated weight of objects received in the target receptacle.
In yet further embodiments the optional safety harness incorporates features that encourage use when wet conditions or aggressive play increase the tendency for slippage and falling from a play swing seat. Various embodiments accommodate as well as challenge the spatial perception, dexterity and reflexes of players of different ages. For examples, younger players might compete by directly spraying opponents swinging in the same or opposite direction. In other embodiments, players must aim either water or other objects at the target to score points, or can simply soak the opposing player(s) with water. The target can be positioned on the ground, hung, associated with the movement of an adjacent players swing or with any moving object on the ground of otherwise, encouraging a higher skill level of interactive play, such as where players in adjacent seats oscillate in opposite directions.
In yet another aspect, the play swing system may alternatively includes a variety of visual or auditory output devices responsive to swing seat movement, target impacts, and the like, for example to indicate the range of swing motion so that bystanders can avoid collisions. Another example includes lights connected to the swing seat and/or supporting structures for games and for improved safety during use at night.
Yet other embodiments of the invention include a soap bubble generators associated with the swing seats movement to provide a slowly dissipating curtain of bubbles that enhance safety by indicating the extent of the swing arc to external observers, while also delighting children.
Alternative embodiments include audio output devices that are optionally responsive to the speed of movement for games and to improve safety during play. This also adds to the interactive play dimension for children as well as alerting adults and others that the swings are in use.
In yet another embodiment of the present invention, various game object and apparatus holders and controls for water, lights, guns, and sound are mounted on the side, front, back, top and bottom of the swing seat, on the swing arms, and on different areas of the play/support structure to enhance various interactive game activities. Preferably, these controls can be moved to various places on the swing set to customize and enhance games. The use of wired and wireless devices to ease installation and game customization and to allow for data transmission to a computer for game and activity feedback and interactivity. In more preferred embodiments of the invention, the safety harness includes an interlock mechanism such that its proper use is required to activate certain games or play activities.
The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view illustrating a player using a swing embodying features of the present invention.
FIG. 2 is a perspective view illustrating a version of a ground mounted target that may optionally be used in conjunction with the swing system illustrated in FIG. 1
FIG. 3 is a perspective view illustrating another version of a swing and system in which two players participate in interactive water games using alternative features of the present invention.
FIG. 4 is a perspective view illustrating a player using a swing embodying alternative water play features of the present invention.
FIGS. 5A and 5B are orthogonal elevations of a swing seat embodying alternative features of the present invention that enable relative rotation of the swing seat for interactive play.
FIGS. 6A and B illustrate the operative principles of swing motion, range and timing measuring devices.
FIG. 7A is a front elevation view of a swing system, whereas FIG. 7B is a side elevation view showing one of the seat and the support structure thereof, whereas FIG. 7C is an expanded side elevation view of a different seat.
FIG. 8A is a cross-sectional elevation of one embodiment of a soap bubble generator disposed on play swing seat.
FIG. 8B illustrates in further detail a subcomponent of the soap bubble generator of FIG. 8A via an orthogonal section to reveal further detail.
DETAILED DESCRIPTION
In accordance with one embodiment of the present invention, FIG. 1 is a perspective view illustrating a play system 100 wherein the player sits on a swing seat 110 , which is suspended from a horizontal frame or member 195 by support cables 112 . The upper end 112 a of support cable 112 connects to horizontal member 195 by a coupling 113 that permits reciprocating movement about an axis parallel to horizontal member 112 such that swing seat connected at lower ends 112 b of support cable 112 undergoes oscillatory motion below horizontal member 195 . Seat 110 can be flexible or rigid, so long as it is sufficiently sturdy to support the player. Further, the seat 110 may have a back-supporting portion similar to a conventional chair, although it is not illustrated in this FIG. As the swing seat and system is intended to permit a variety of play activities that require a free hand, for example in this FIG., the player is holding a ball 135 in his right hand; the seat preferably further comprises a safety harness 115 for restraining the forward motion of a player out of the seat. Safety harness 115 can be attached to either the suspending cable 112 , or seat 110 , or an optional seat back. Harness 115 may comprise, as illustrated, one or more flat straps that meet at or near the player's chest and connect with a snapping buckle 116 . As will be further discussed, other aspects of the invention provide for a range of additional components used in interactive play that generally require a free hand to operate or otherwise engage in.
When seat 110 is intended for use with target games, as will be further described below, the seat may also include a container 130 for storing balls, related throwing objects as well as related play equipment. Container 130 is optionally attached to the seat 110 directly, a seat back (not shown in this FIG.) or any portion thereof, so long as it is readily accessible to the seated player. Preferably it is designed so that it does not adversely affect swing balance, momentum or pose a safety hazard to another player or spectator. Alternatively, harness 115 may be connected to the seat through container 130 . Although container 130 is illustrated as a mesh type storage sack, it might also comprise a rigid or semi-rigid container and that could be fabricated or molded into a rigid seat 110 , particularly a rigid seat having a seat back. The mesh type presently preferred is fabricated from an elastic material to conform around the contents, thus preventing play objects from moving, shifting or escaping unintentionally during use. It should be understood that the proposed throwing objects and accessories includes soft balls, waffled or semi-rigid balls formed having a semi-perforated shell, foam balls, bean bags, “FRISBEE”-like objects, cushion tipped throwing projectiles, and the like.
In accordance with another aspect of the invention, FIG. 2 is a perspective view illustrating a version of a ground-mounted target that may optionally be used in conjunction with the swing system illustrated in FIG. 1 . As will be further described targets can be mounted from the swing itself, including swing seats, laid horizontal or flat on the ground, as well as in a partly upright position, being spaced away from the swing play area, as shown in FIG. 2 . Target 200 has a peripheral frame 210 comprising an arching segment 210 a and a horizontal segment 210 b . Horizontal segment 210 b connects at right angles near opposite ends of arched segment 210 a , with the remaining segments of the arch portion 210 b extending as supporting legs 211 and 212 . Thus, the peripheral frame 210 is readily fabricated by flexing semi-rigid tubing to form the arch segment 210 a , wherein the horizontal segment 210 b is preferably constructed of tubing that is more rigid; for restraining the flexed tubing to maintain the arch shape. The face of target 200 is fabricated from fabric, “VELCRO” type hook and loop fasteners, or fence type mesh 215 that is laid or stretched over frame 210 . The mesh 215 is marked with one or more zones 216 and 216 ′, preferably concentric circles to represent increasing different point values for competitive play. Throwing object 235 is a projectile having an aerodynamic cone shaped tip 236 at the front end. The base of the cone is slightly larger than the mesh opening such that throwing object 237 has been retained by the mesh upon contact. The retaining features of the projectile and cone facilitate the tallying of the score as the players remove the projectiles at the end of the game. Alternatively, when the throwing objects are balls, beam bags or other have otherwise regular aerodynamic shapes, the target area may simply be one or more container such that the opening is the target area. Target 200 has the advantage that it is lightweight and can be mounted at various distances from the swings by pushing legs 211 and 212 into soft ground. Further, the difficulty of hitting the central target area 116 ′ can be increased by decreasing the angle that legs 111 and 112 make with the ground. Decreasing the angle of the target encourages further physical activity, that is players will recognize that “pumping” the swing to a higher elevation increases the projected target area making it easier to aim at and hit central target area 116 ′.
As will be illustrated in various other embodiments, alternative forms of targets are mounted in association with each swing seat for receiving an object thrown by a player in an adjacent seat swinging in the opposite direction. While target 200 is generally intended to receive and retain an object 235 thrown by a player in the swing, any of the targets described herein can also be a photoreceptor target for electronic laser tag type play (where a player uses a very low power laser gun) or otherwise controls a light or projectile source from the swing or swing movement. When the targets include laser tag sensors, which are preferably mounted on a moving part of the swing seat, such as the players the safety harness.
FIG. 3 is a perspective view illustrating two players in an interactive water game on another version of a swing system embodying different features of the present invention. Each of seats 311 and 312 has a water trough 341 and 442 mounted on the horizontal member 195 above the player. Water troughs 341 and 342 are filled via water source 330 that runs along horizontal support 195 . Water source 330 is generally a conduit that extends downward toward ground level along vertical support leg 190 where it is coupled to an ordinary garden hose 332 at port 331 . A floating valve or other fill level response switch is preferably disposed at or in the water troughs such that trough can be filled to near capacity after emptying. The object of the game is to throw an object, or otherwise activate the target, at the opposing player's target, such as 321 , and drench the player in seat 311 with water from the self-filling water trough 341 as shown. The water trough is optionally mounted on a flexible hinge, joint or gimbals such that it will normally be upright but is tipped over or otherwise releases water out of the bottom in response to the movement or other actuation of the associated target. The target 341 can be directly coupled to the trough so the water is dumped by either disturbing the balance of the trough or by releasing a latch or shutter, which normally prevents the trough from tipping under its own weight. It will be recognized by one of ordinary skill in the art that there are many alternative types and locations for water-releasing sources, for example, the trough can be placed between the suspending cables 112 , and thus moved closer to the player. Alternatively, hitting the target can activate a self-closing aperture at the bottom of the trough so that the water is released as a slow downward shower to wet the player when they swing directly under the horizontal support 195 . In yet another embodiment the target can have multiple zones that cause either a fast or slow emptying of the trough. Alternatively, the water trough can be mounted on gimbals associated with the seat suspension members 112 that extend downward from the horizontal frame 195 .
It will be further recognized by one of ordinary skill in the art that the use of a trough or other water storage vessel above the players is not essential, as it can be replaced by spray or misting nozzles, that are either continuously on or open in response to hitting a target, movement of the swings, or manually operated as dictated by game rules and activities.
In a further alternative embodiment the targets motion upon projectile impact is coupled to actuate the valve that fills the trough with water. Thus, the trough mounting can be otherwise independent of the target, for example by a flexible hose, such that the trough dumps water or overflows in response to an imbalanced weight distribution upon filling. In all these embodiments, it is preferable that the timing of the release of the water can be controlled to maximize the fun.
Yet another alternative embodiment is to provide a container for capturing water from spray nozzles or other water outlets associated with water source, which for example can be responsive to accumulated contact of throwing objects with the target. Alternatively, the spray nozzles are optionally connected to water trough such that player can only spray water when trough is at least partly full.
Alternatively the flat target shown in FIG. 3 can be replaced with an open container for receiving throwing objects or water whereby the accumulated weight of throwing objects captured by the target receptacle provides a force that releases any of the previously described actuation mechanisms to release, dump, shower, spray or mist water onto at least one of the players. The target need not be suspended from horizontal member 195 , but can also be attached to the adjacent swing seat, as is further described with respect to FIG. 4 .
FIG. 4 is a perspective view illustrating a player in another version of the swing embodying alternative water play features of the present invention. As in FIG. 4 , swing seat 110 is designed for suspension from a horizontal frame 195 (not shown) via cables 112 for oscillatory motion. Water from source 340 (not shown) flows down toward the seat 110 via a pipeline 430 wrapped around suspending cables 112 . A water pistol 415 , held in the right hand of the seated player is in fluid connection with pipeline 430 via flexible tubing 431 . The flexible tubing 431 is preferably stress relieved by a secure attached to suspending cable 112 . By water pistol we mean to include any type of spray or squirt nozzle a player can aim at another player, spectator or target either by hand or otherwise. Accordingly, the water gun need not resemble an actual weapon, but can be any form of a squirt or spray orifice mounted to a wand, flexible hose wand or attached or integrated with the seat. A hand held water pistol 415 is preferably tethered to seat 110 on an optionally retractable leash or a supporting strap or mount that stress relieves tubing connection and/or tether when the player does not hold the pistol.
Alternatively, the water pistol can be of the conventional type, drawing water from a closed reservoir, such as that disclosed in U.S. Pat. No. 5,603,361, which is incorporated herein by reference. Accordingly, the seat 110 may include provisions for storing water, or mounting a detachable reservoir, squirt gun or pistol. For example, the water pistol may be in the form of spray nozzles 425 mounted on the seat. The spray nozzles in this case would be controlled manually by release lever 428 . Fixing the spray nozzle to the seat could increase the difficultly in hitting the adjacent player, as exposure to the water spray or stream is limited to the portion of the oscillatory motion that depends on the players relative speed.
Release lever 428 optionally opens and rotates to direct a higher velocity water jet through tube 426 having a larger diameter opening than the orifice of spray nozzle 425 or 425 ′. Thus, release lever 428 enables the player to release a high volume of water as a jet to modify or modulate the swing velocity. Specifically, by rotating tube 426 using the handle or release lever 428 the jet can be directed opposite the direction of the swings current movement to increase the speed and height, or into the direction of motion to slow the swing.
Alternative targets include those that accumulate water sprayed or squirted directly therein, and optionally include a weight or balance responsive actuator that dumps, sprays, streams or otherwise releases the accumulated water in target container onto the player in the seat. In addition to providing fixed spray nozzle 425 for shooting another player or spectator, or demountable spray gun for aiming at a target, additional spray nozzles are also optionally mounted above seat of opposing player for control by a player in another seat, independent of the target use or location. For example, in FIG. 4 an optional target 420 is disposed above the player sitting in seat 110 . Target 420 can be used in conjunction with other accessories for either wet recreation or scored game play. For wet play, spray nozzles 425 ′ is connected to the water source via a valve actuated by impact or other actuation of target 420 , which can include the force from water sprayed onto target 420 by another player.
Many of the play activities enabled by various features and embodiments of the instant invention are interactive and require at least adjacent players to see each other during at least a portion of the swings oscillatory motion. Thus, FIG. 5 illustrates yet another embodiment wherein the players can alternative orientation with respect to the plane of the oscillatory motion depending on the play activity. More specifically, as shown for play system 500 in FIG. 5C , it is desirable to configure adjacent seats 511 and 512 so that players are transverse to the direction of swing oscillation and facing each other, in contrast to seat 510 , in which the player faces forward, in the direction of swing oscillation. Accordingly, players in swings 511 and 512 can more readily engage in interactive play that involves targeting the other player, for example using the squirt gun or targets illustrated in FIG. 3 or 4 .
Another embodiment, shown in FIGS. 5A and 5B provides for the conversion of swing seats from the configuration of seat 501 to 503 by rotation during interactive play. FIG. 5A corresponds to section A-A′ through seat 510 of FIG. 5C , whereas FIG. 5B is the corresponding orthogonal elevation. As the swing seats in FIGS. 5A and 5B may also include targets of the types previously described or illustrated, the player's ability to rotate the seat during oscillation creates a further play challenge wherein players may perturb the target position by rotating the seat as the player releases a projectile, water, or activates a light or laser gun.
FIGS. 5A and 5B are intended to illustrate another alternative embodiment for mounting a safety harness 515 to the swing seat 510 . Harness 515 is secured to support cable 516 and 516 ′ but is at least releasable to translate along the support cable length so that players lift the harness up for egress and entry, as shown in FIG. 5B , lowering it toward the seat bottom 510 b after the player enters seat 510 .
It should be recognized that principle of harness movement or engagement to protect the player is equally applicable to the other games and activities that might require the player's movement or removal of at least one hand that would otherwise be used to grasp the seat or a related supporting structure.
It should also be appreciated that in any of the aforementioned embodiments, the description of a seat or seat bottom for sitting is intended to encompass alternative shapes and structure that permit or encourage safe play while standing, lying in a prone position, and the like.
It should be further appreciated that the embodiments encompassing a rotating seat do not preclude combinations with targets previously described, particularly those that are operatively coupled to a water source or water source actuator, as well as the propulsion water source, nozzles or squirt gun. The water source or point of release can be connected to any of the structure above the rotary coupling 545 . Alternatively, a continuous water source can be disposed co-axial with the rotary couplings axis of rotation, using a rotary fluid fitting. Alternatively, the rotary coupling can be suitably limiting in the range of rotary motion such that a flexible conduit or pipe that traverses between the fixed platform 545 and rotary platform 540 would not be tangled or severed from repeated rotation in the same direction. Accordingly, the optional positions for the terminus or outlets of a water source include the seat back 511 , seat bottom, 510 b , suspending cables 516 and safety harness 515 . Preferably, the water actuator or targeting control is disposed on a common component or actuator with release lever 514 , for example, a component that emulates an aviator's joystick, a steering wheel, and arm support console, and the like.
It should be appreciated that alternative embodiments for competitive game play include utilizing a target that rotates, or otherwise move, at the players control or independent of seat rotation controlled by player. For example, the seat might remain fixed, while the only the target is cable of independent rotation or other movement apart from the oscillatory motion of the swing seat.
In yet other embodiments, target activation, by an opposing player, optionally engages seat rotation, for example by de-latching the stop or release mechanism associated with rotary coupling 525 .
Alternative embodiments of the invention utilize lights, sound or other types of information displays that are responsive to the motion of the swings themselves, thus suitable for interactive play by younger players, or educational games as will be further described below. Accordingly, FIG. 6 illustrates the operative principles of a sensing device 600 for determining at least one of the height, frequency or speed of the swing during oscillation. The purpose of the sensing device is to record the time at which the swing seat reaches the maximum of height during the oscillatory motion and record the height. It should be appreciated motion and position-sensing devices are known in the art field of factory automation, robotics and material handling, therefore FIG. 6 should be understood to be merely illustrative of the operational requirements of such device as they relate to providing the inventive functions described herein.
As illustrated by the plan view in FIG. 6B sensing device 600 is preferably mounted in association with horizontal member 195 and disposed adjacent to suspending cables 112 associated with each seat. Sensing device 600 includes one or more light emitting devices 610 and associated photodetectors 615 spaced apart there from such that a free space optical path, indicated by straight arrays from emitters 610 to associated detectors 615 , will be interrupted by the oscillatory motion of the swings seat suspending cable 112 . FIG. 6A is an elevation of detector 600 taken through section A-A′ in FIG. 6B to illustrate the array of photodetectors 614 as viewed from the light emitter director with intervening swing suspension cable 112 . Sensing device 600 preferably includes an array of photodetectors 614 co-mounted on a plate or support 615 to span the potential range of motion of suspending cable 112 . Plate 615 is disposed on a support bracket 611 such that it extends out from horizontal member 195 to encompass the free range of motion of suspending cable 112 . Accordingly, one or more light emitting devices 610 provides a beam that extends to include the detector array 614 such that the time sequence of adjacent photodetectors in group 614 receiving a null signal, caused by the blocking of the light beam from emitter 610 , will indicate the passage of the suspension cable as the swing oscillates. The position of the suspending cable 112 at the greatest height of the swing oscillation corresponds to a position between the last photodetector in array 614 to be interrupted (which in this figure is detector 614 b ) and the first photodetector not to be interrupted ( 614 c ) during a repeating sequence of interruptions. Specifically, detectors 614 a to 614 e null signals will be detected in the temporal sequence a-b-a. The detector array 614 is optionally symmetrically disposed about horizontal member 195 to cover the full range of oscillatory motion; however, for most purposes the non-symmetric array illustrated will be sufficient, as the momentum or height change between is not expected to be significant during a single oscillation cycle. Accordingly, by providing a timing and logic circuit responsive to the variations of photo detector signals, and using a geometric correction to account for the total length of suspending cable 112 , the maximum height of the swing is readily determined by a microprocessor for communication to players and/or spectators by various methods, as will be further described. Further, the same logic circuit can be configured to determine the elapsed time between each instance of reaching the maximum height during the swing oscillation, for determination of the instantaneous or maximum swing velocity, as well as to count the number of oscillation cycles.
Thus, the several parameters that reflect movement of the swing can be communicated to the players as well as observers by additional electronic methods and output devices, including lights and visuals displays that provide an analog output, digital displays or auditory output using loudspeakers, which are further described with reference to FIGS. 7A , B and C.
FIG. 7A is a front elevation view of swing system 700 having a variety of optional lighting devices, power sources and control systems associated with the supporting structure or the swing seats. For example, light emitting devices 715 can be an array on a flexible cable that extends along swing seat suspending members. Alternatively, fiber optic lights can be deployed in the same manner, for example with lighting cable or fiber bundle 710 wrapped around horizontal and vertical support members. Light emitting devices 716 are optionally integrated into the swing seat structure 710 , as well as external or detachable device 718 . As shown in FIGS. 7A and 7B lights or light array 716 can be associated with one or more of the front, back, or side of seat 710 . Thus, light emitting device 716 as mounted on the side of seat 710 in FIG. 7B , will indicate the range of the seat oscillation to an external observer at night. As swing system 700 comprises a large number of linear elements, such as the horizontal or vertical support frames and suspending cable, a preferred light emitting device is a fiber optic cable designed for continuous side emission. As the fiber optic lighting fixture is end coupled to a light source, the light source is not generally limited by the considerations of having an electrical power supply near wet play areas.
As previously mentioned light sources include Laser or focused lights for aiming at targets, such as for laser tag type play. Accordingly, such hand held devices are preferred attached to the seats by a retractable tether, as described for the water pistol. Alternatively, either Laser or focused lights 719 on seat 710 b can be fixed to the side or bottom of a seat to illuminate the ground alternatively display the range of seat movement during oscillation.
Alternative lighting devices include incandescent sources, fluorescent sources, black lights, as well as light emitting diodes, electro-luminescent lights and the like.
Light power sources optionally include solar cells 706 , shown in a preferred location mounted on horizontal swing support member 195 , it being understood that the energy generated by photovoltaic solar cell recharges a battery that can operate any alternative electronic device disclosed herein.
Alternative light, speaker or motor power sources include low voltage via transformer 705 connected to power mains, as well as battery, regular line voltage, but can also include power generated by a piezoelectric transducer coupled to the oscillating motion of the swing.
The form of light output may include changes in selection, power or pattern of lights triggered for challenging players by indicating a maximum height or velocity, as well as absolute position during the swing. Analog displays include any method of triggering or varying the spatial or temporal output of lighting fixtures that might be arranged on the fixed or moving structures of the swing, such as device 715 and 716 . For example, a light pattern might be purely temporal, that is a one or more flashing lights, or a time sequenced illumination of a series of adjacent lights, i.e. to display a moving bar or object.
Digital output might include a numeric display, for example a score display board 755 , which is shown in one of many alternative locations being mounted on suspending cable 112 . However, a digital output might also include icons having a size, color or shape to represent a number, a relative quantity or a progressive change.
Further, the output of the logic circuit, associated with device 600 in FIG. 6 , might include control of safety lights that point to positions on the ground thus warning spectators to avoid colliding with the moving swing by staying outside a marked area. Alternatively, the logic circuit output might simply trigger general light or output speaker to signify that the swings are being used, thus alerting adults whose attention and supervision of smaller children might be required.
Various forms of auditory output device may be used with or substitute for at least some of the entertainment and safety functions of visual lighting. For example, the auditory output may include changes in volume, pitch or continuity to reflect the player's maximum height or velocity, as well as absolute position during the swing. For example, as logic circuitry can also maintain a record of the previous height reached, with the pitch, volume or continuity of the signal changing as the swing position approaches this height. If the play reaches a higher level than the previous cycle one or more additional indicators might be provide a distinct output to distinguish between decay of oscillation. FIG. 7C illustrates one embodiment for locating such lighting output control devices, speakers or control circuits associated therewith. Thus, output speaker 718 is mounted below the seat. Further, the various lighting fixtures and features described above can optionally operate manually, by the player from a seat-mounted console 717 , or by a spectator at a distance, such as to provide sufficient light that encourages or extends the hours available for safe play.
Alternatively, the output might include a synthesized or recorded voice announcing a numeric score or outcome, or to change players after fixed number of cycles, time of use, or a competitive criteria. Further, the synthesizer-recorded voice might be combined with a digital or pictorial display that reinforces counting of numbers, the alphabet, addition or subtraction or other elementary school activities.
Further, the auditory output need not be an electronic speaker, but may alternatively comprise a whistle or other device that produces a sound in response to the high air velocity with respect the moving seat. Accordingly, the sound generating device may be incorporated into the seat or any other moving fixtures associated, such as a whistle or speaker output 718 mounted below the seat. A whistle preferably includes a horn or cone shaped entrance orifice to collect and increase the velocity of air in front of the swings path without creating turbulent flow, which might adversely affect the output. Accordingly, such manual devices may function as musical instruments, and also include baffles, holes or other sound or pitch modulating mechanisms that controlled by the seated player. Sound generating device such as air whistle or related wind instrument are optionally responsive to movement and velocity of the swing seat such that pitch and/or volume changes with speed.
FIG. 8 illustrates another embodiment of the invention in which a soap bubble generator 800 is coupled to at least a portion of the swing seat 110 to produce bubbles during swing movement. In a preferred embodiment, the bubble generator provide a visual indicator of the range of seat swing motion as it releases bubbles along the path of the swing to form a constantly dissipating curtain that visible to both players and observers. The curtain boundaries provide an indication of the range of the player swing during the previous cycles of oscillation.
The bubble generator 800 represents an embodiment that operates in response to swinging motion of seat 110 to produce a continuous stream of bubbles 801 . As shown in the cross sectional elevation through generator 800 in FIG. 8A , incoming air moves in the relative direction of arrow A with respect to the seat, while the seat moves in the direction of arrow B with respect to the ground. A funnel or cone shape orifice 810 at the forward side of generator 800 collects air in front of the swing seat path to provide a higher velocity air stream as the cone narrows to channel 811 . The higher velocity air in channel 811 is directed to a bubble-generating chamber 812 . Bubble generating chamber 812 has an outlet orifice 813 and a bubble-generating frame 820 disposed between the air inlet channel 811 and the outlet orifice 813 . The bubble generating frame 815 can be either stationary, responsive to the oscillatory motion of the swing, or under the control of the player, provided it continuously encounters a sufficient quantity of soap bubble solution. In this embodiment, soap solution is provided by reservoir 830 disposed at the bottom of chamber 812 . FIG. 8B is a detail elevation showing the front of bubble generating frame 820 . The frame 820 is a disc comprising at least two panels 821 and 822 disposed on opposing sides of a central spindle 816 for rotation about axis 815 in FIG. 8A . Each of frame panels 821 and 822 is submerged in the soap solution reservoir 830 during each rotation cycle about the rotary axis 815 , such that they are subsequently exposed to the air stream entering chamber 812 from channel 811 . As a soap film will become suspended across frame panels 821 and 822 upon their removal and draining of excess solution (back into reservoir 830 ), the air jet emerging from channel 811 will deforms the suspending soap film causing the formation of a plurality of soap bubbles, which then exit with the air jet, through the outlet orifice 813 . Frame 820 in FIG. 8B also includes propeller blades 850 disposed between frames panels 821 and 822 such that the incoming air urges a continuous rotary motion about axis 815 creating a relatively continuous stream of bubbles. The reservoir 830 is manually filled or optionally constantly replenished by gravity or pump fed source. It will be recognized that two or more generators can be combined to produces bubbles as the seat oscillates in both direction, or a second cone can be provided in the opposite direction that connects to channel 811 or another opening into chamber 812 .
Thus, the bubble generator 800 provides entertaining and challenging play activity for younger children, as the quantity, type or size of bubbles is optionally responsive to the swing velocity or alternative controls available to the player.
The soap bubble generator can alternatively be independent of swing movement; for example, it might include a manual lock of moving components, like frame 820 , to conserve soap solution, as well as other controls to vary the quantity and quality of bubbles for competitive play as well as entertainment. Further, the soap bubble generator is optionally powered by a motor to control either a fan, for blowing air against a soap film-forming frame, moving the frame to replenish the bubble film, or operating a pump to supply soap solution to the frame directly, or fills generator from a remote reservoir. Alternatively, a pump may be deployed to force soap solution through an orifice in combination with an air stream to generate soap bubbles. Power for a non-swing operated bubble generator includes hand power or any electric power source previously taught for lighting purposes.
It will be recognized that the bubble generating device can be an accessory for attachment to various parts of the seat, or integrated with the seat structure, that is below the seat or in a side console.
While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.
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A play swing system includes a safety harness attached to each seat, as well as other features for interactive and competitive throwing and tossing games. The safety harness may incorporates various games features, and thus encourage use in activities that require at least one free hand, or otherwise increase the risk of slippage and falling from the play swing seat. Various embodiments accommodate as well as challenge the spatial perception, dexterity and reflexes of players of different ages. For examples, younger players might compete by throwing objects at a fixed target mounted on the ground. In other embodiments, the target is moving in synchronization with the oscillatory motion of the adjacent players swing by a physical coupling or attachment. Interactive play is encouraged at the higher skill levels by configuring the targets associated with adjacent seats to face each other. In this embodiment, the players oscillate in opposite directions so that they are closest to the target when the relative velocity is highest. The objects of the associated games can be building a higher score, as well as soaking the other player(s) with water supplied by an external source and actuated by instantaneous or accumulated contact of a throwing object with a target.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for generating a robot program and also relates to a device for analyzing a robot program. More particularly, the present invention relates to a robot program generating device for generating a robot program useful for effectively raising a production system in which a robot and visual sensor are used or for generating a robot program useful for maintaining the production system after it has been raised. The present invention also relates to a robot program analyzing device for analyzing the robot program.
2. Description of the Related Art
There has already been provided a production system including a process in which a fixed camera or a movable camera mounted on a robot is used as an image snapping means for a visual sensor together with a robot and in which a large number of parts, which are not arranged in order, are successively taken out and conveyed to the next process. This production system has already been put into practical use under appropriately determined conditions. This robot-visual sensor system for handling a large number of parts, which are not arranged in order, is going to enter into a practical phase from a trial phase recently so as to spread into various applications. For example, as disclosed in the Japanese Unexamined Patent Publication No. 2003-34430, the operation of a system, the practical use of which has been conventionally assumed to be difficult, has now started.
However, in the case of the above application in which the visual sensor is used, it is necessary to select a measuring position and measuring method conducted by a visual sensor while consideration is being given to the object of the work to be done and the size and shape of a workpiece to be handled. Therefore, a heavy burden is imposed on the operator. For example, assume a case in which a visual sensor is used, the measurement accuracy represented by the visual angle range of which is 0.5°, in order to grip both end portions of a work of 2 m long by a robot hand. In the case where both end portions of the work are gripped by the robot hand after only one end portion of the work has been measured using the visual sensor, the measuring accuracy of which is 0.5°, a gripping error at the other end portion is not less than 17 mm (2000 mm×2×π×0.5/360). Accordingly, the selection of the above measuring point and measuring method is not appropriate unless a handling mechanism capable of absorbing the above error is used. In this case, it is necessary to conduct a measurement on the other end portion of the work so as to reduce the error caused in the measurement.
In the case where it is impossible to ensure the detection accuracy since a difference between individuals of the shape of the characteristic portion to be used as the measurement portion is large, it is necessary that the characteristic portion is excluded from the measuring portion and that another characteristic portion is determined as the measuring portion.
In order to appropriately determine the measuring portion or the measuring method, it is necessary to consider a large number of conditions such as a size, shape and fluctuation of the work and an accuracy of the visual sensor and a characteristic of the handling mechanism. However, it is an actual condition that the repetition of trial and error has been needed in the job site up to this time, in order to raise the system. In the case where the system has been raised by a user without accurately understanding these necessary conditions and a relation between the measuring portion and measuring method, even if the system is fortunately, excellently operated at first, trouble may be caused after that, for example, the system is stopped once a day, and it is difficult to specify the cause of the trouble. This problem becomes a heavy burden for the user, which becomes a cause of obstructing the introduction of the visual sensor robot system.
It is an object of the present invention to provide a robot program generating device capable of solving the above problems of the prior art. It is also an object of the present invention to provide a robot program analyzing device capable of analyzing the generated robot program. That is, it is an object of the present invention to reduce a burden imposed on a user in such a manner that know-how to use a visual sensor is incorporated into a device, which is capable of generating or analyzing a teaching program of a robot, such as a robot simulator, and a proposal and judgment can be made with respect to a work size, measuring position, measuring condition and correcting method etc.
SUMMARY OF THE INVENTION
First, the present invention solves the above problems by a robot program generating device for generating a robot operating program.
According to aspect 1 , a robot program generating device for generating a robot operating program, comprises: a means for displaying a work model; a means for designating a measuring portion measured by a visual sensor on the displayed work model; a means for designating a measuring method for measuring the measuring portion; a means for designating information about the work; a means for storing reference information for judging whether or not the measuring portion is good and/or whether or not the measuring method is good corresponding to the designated information; a means for judging whether or not the designated measuring portion is good and/or whether or not the designated measuring method is good according to the reference information; and a means for generating a robot program according to the designated measuring portion and/or the measuring method, the robot program including a measuring command for executing the measurement of the designated measuring portion and/or a measuring command for executing the measurement according to the designated measuring method.
According to aspect 2 , a robot program generating device for generating a robot operating program, comprises: a means for displaying a work image which has been previously snapped; a means for designating a measuring portion measured by a visual sensor on the displayed work image; a means for designating a measuring method for measuring the measuring portion; a means for designating information about the work; a means for storing reference information for judging whether or not the measuring portion is good and/or whether or not the measuring method is good corresponding to the designated information; a means for judging whether or not the designated measuring portion is good and/or whether or not the designated measuring method is good; and a means for generating a robot program according to the designated measuring portion and/or the measuring method, the robot program including a measuring command for executing the measurement of the designated measuring portion and/or a measuring command for executing the measurement according to the designated measuring method.
In these inventions, the information about the work can include at least one of the work size, the work material, the work gripping method and the work loading state (aspect 3 ). The robot program generating device can be a robot simulator having a function of executing a simulation for the robot program (aspect 4 ).
Next, the present invention solves the above problems by a robot program analyzing device for analyzing a robot operating program.
A robot program analyzing device for analyzing a robot operating program of aspect 5 comprises: a means for inputting and analyzing a robot program; a means for displaying a work model; a means for displaying a measuring portion measured by a visual sensor from the analyzed program on the displayed model; a means for displaying a measuring method for measuring the measuring portion; a means for designating information about the work; a means for storing reference information for judging whether or not the measuring portion is good and/or whether or not the measuring method is good corresponding to the information about the work; and a means for judging whether or not the measuring portion is good and/or whether or not the measuring method is good in the program according to the reference information.
A robot program analyzing device for analyzing a robot operating program of aspect 6 comprises: a means for inputting and analyzing a robot program; a means for displaying a work image which has been previously snapped; a means for displaying a measuring portion measured by a visual sensor from the analyzed program on the work image; a means for displaying a measuring method for the measuring portion; a means for designating the information about the work; a means for storing reference information for judging whether or not the measuring portion is good and/or whether or not the measuring method is good corresponding to the information about the work; and a means for judging whether or not the measuring portion is good and/or whether or not the designated measuring method is good in the program according to the reference information.
In these robot program analyzing devices, the information about the work can include at least one of the work size, the work material, the work gripping method and the work loading state (aspect 7 ).
A robot simulator having a function of executing a simulation for the robot grogram can be employed as a robot program analyzing device (aspect 8 ).
A summary of the operation of the present invention will now be given below.
In the robot program generating device of the present invention (aspects 1 to 4 ), a view of the work model or a snapped image of the work is displayed. On the displayed work model or on the displayed snapped image of the work, a measuring method of the work or a measuring portion of the work is designated. Further, the information about the work is designated. Based on the foregoing, it is judged whether or not the work measuring method and the work measuring portion are appropriate. Further, when they are appropriate, a robot program including a command of measurement is generated.
A robot program analyzing device according to the present invention (aspects 5 to 8 ) reads and analyzes a robot program and displays the work model or an image of the work which has been snapped, and further displays a work measuring method and a work measuring position on the displayed work model or the displayed image of the work. Further, by designating the information about the work, it is judged whether or not the work measuring method and the work measuring portion are appropriate.
According to the robot program generating device of the present invention, the judgment of appropriateness of the measuring portion and the measuring method, which was conventionally conducted by a user in a job site by the method of trial and error, can be previously conducted. According to the robot program analyzing device of the present invention, even after the system has been constructed, the appropriateness of the system can be verified. Therefore, it becomes easy to specify the cause of a system problem which has occurred during the operation.
Further, due to the effects described above, a burden which is imposed on a user in the system using the visual sensor can be reduced. Therefore, it can be expected that the introduction of the system will be facilitated.
These and other objects, features and advantages of the present invention will be more apparent in light of the detailed descriptions of exemplary embodiments thereof as illustrated by the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is an overall arrangement view of an embodiment of the present invention;
FIG. 2 is a flow chart showing an outline of the processing executed in the embodiment;
FIG. 3 is a view showing an example of the work model (or the work image) and the measuring portion, which are displayed on an image plane, in the embodiment;
FIG. 4 is a view for explaining an example of the designation of the work information in the embodiment;
FIG. 5 a and FIG. 5 b are flow charts showing an outline of the processing for making a diagnosis on a measurement error in the embodiment;
FIG. 6 is a flow chart showing an outline of the processing for making a diagnosis on gripping displacement in the embodiment;
FIG. 7 is a flow chart showing an outline of the processing for making a diagnosis on the influence of deflection of the work in the embodiment;
FIG. 8 is a flow chart showing an outline of the flow of the entire diagnosis in the embodiment;
FIG. 9 is a view for explaining a method of calculation of the maximum gripping error in “another item 1 ”;
FIG. 10 is a view for explaining a method of calculation of the maximum gripping error in “another item 2 ”;
FIG. 11 is a block diagram in the case where a computer is used for the robot program generating device; and
FIG. 12 is a block diagram in the case where a computer is used for the robot program analyzing device.
DETAILED DESCRIPTION
FIG. 1 is a view showing an outline of the overall arrangement of one embodiment of the present invention. In FIG. 1 , reference numeral 1 designates a robot to handle an article (not shown) such as a work. In the neighborhood of the wrist of the robot, the video camera 2 and the hand 6 are attached. The video camera 2 functions as a sensor head of the visual sensor. The personal computer 3 , which will be referred to as a computer hereinafter, controls the operation of picking up an image conducted by the video camera 2 and processes an image which has been snapped. The robot 1 is connected to the robot controller 4 , and the robot controller 4 and the computer 3 are connected to each other by the network line 5 .
The computer 3 functions as a controller for controlling the visual sensor on line. On the other hand, the computer 3 functions as a robot simulator used for both the robot program generating device and the robot program analyzing device off line. The computer 3 is provided with a monitor 90 (for example, a liquid crystal display device) and a manual operating section 91 (such as a keyboard, mouse and so forth) in a well-known connecting method. The monitor 90 displays a snapped image and a processed image obtained when the image, which has snapped before, is processed on line or off line. The monitor 90 is used to display off line an image of the work model or the robot model used for off-line programming. The monitor 90 is also used to display off line an image previously snapped by the video camera 2 . The manual operating section 91 is used for inputting various data onto the image plane on which the above image is displayed. That is, the manual operating section 91 functions as a measuring portion designating means 91 a for designating the measuring portion, a measuring method designating means 91 b for designating the measuring method and a work information designating means 91 c for designating the work information described later.
In this connection, the visual sensor used in this embodiment is of the type in which the video camera 2 is used as a sensor head. However, as necessary, the other type of visual sensor may be used, for example, the visual sensor may be replaced with a three-dimensional type visual sensor by which a three-dimensional position and posture of the object can be recognized by projecting a beam of reference light such as a beam of slit light.
FIG. 2 is a flow chart showing an outline of the processing when the present invention is executed while the computer 3 used as a robot simulator is made to function as a robot program generating device and a robot program analyzing device. In this connection, the processing step numbers of 100 level correspond to the function as a robot program analyzing device, and the processing step numbers of 200 level correspond to the function as a robot program generating device. In this connection for the convenience of explanations, the processing (the function as a robot program generating device) to which the step numbers of 200 level are numbered, will be first explained. At this time, FIG. 11 is appropriately referred to, and which is a block diagram in the case where the computer 3 is used as the robot program generating device.
First, a model of the work is displayed on the monitor 90 of the robot simulator (step 201 ). In this case, the robot simulator is the computer 3 , which is the same in the following explanations. As well known, for example, a model of the designing data of CAD can be utilized for this display model. Instead of the model, an image of the work corresponding to the model may be snapped by the video camera 2 so as to take in the data of the work. Then, the image of the work may be displayed on the monitor 90 . In this case, an image displayed on the monitor 90 is represented by the “model” including the “image”, which is the same in the following explanations.
Next, a portion to be measured, namely measuring portion, is designated in the model displayed on the monitor 90 (step 202 ). This designation is conducted by an operator with the manual operating section 91 such as a mouse. At the time of designation, it is possible to employ a system in which the operator arbitrarily selects a portion to be measured. Except for the above system, it is possible to employ a system in which portions in the designing model, the contrast of which is judged to become clear, such as a sharp step portion and a hole portion, are automatically selected with the robot simulator and presented on the image plane, and the operator selects one of the selected portions. In the case where an image, which has been snapped, is used, portions in the actual image, the contrast of which is clear, are presented while the portions are emphasized being turned on and off, and of the thus emphasized portions may be selected by the operator.
Next, the measuring method for the above measuring portion is designated (step 203 ). Usually, either the two-dimensional measurement made by the video camera 2 or the three-dimensional measurement made by the three-dimensional visual sensor is selected. This designation is conducted by the operator with the manual operating section 91 such as a keyboard. In this connection, the processing described in steps 202 and 203 may be repeated when necessary so as to conduct measurements on a plurality of portions.
Next, information about the work, which will be abbreviated as “work information” hereinafter, is designated by the manual operating section 91 (step 204 ). The typical work information is data of the work size, the work material, the work gripping method and the work loading state. In this case, the work size, the work material, the work gripping method and the work loading state are designated by numerical values. Concerning this matter, specific examples are described later.
Next, it is judged whether or not the measuring portion and the measuring method are good (step 205 ). For example, the rule applied to the above judgment of the measuring portion is whether or not the contrast capable of stably detected by the visual sensor is obtained at the measuring portion. Another rule applied to the judgment of the measuring portion is that, for example, in the case a work is a thin metallic sheet, since an end portion of the work is easily bent or flexible, the end portion of the work is not appropriate as the measuring portion. The rule applied to the judgment of the measuring method is that when the work is stably loaded, the two-dimensional measuring method may be employed. However, when the work is loaded unstably, it is necessary to designate the three-dimensional measuring method. Another rule to be applied to the judgment of the measuring method is described as follows. In the case of a work of a large size, for example, in the case of a work, the maximum diameter of which is not less than 1 m, it is necessary to measure at least two portions which are separate from each other by the distance of not less than 50 cm. Another rule to be applied to the judgment of the measuring method is described as follows. In the case where the degree of absorbing an error of the gripping method is large, even in the aforementioned work of a large size, it is sufficient to use only one measuring portion. These rules are stored in the storage section 92 of the computer 3 as the reference information for judging whether or not the measuring portion and/or the measuring method is good. According to these rules, whether or not the measuring portion and/or the measuring method is good is judged by the judging means 93 of the computer 3 .
In the case where the measuring portion and/or the measuring method is judged to be good, the robot operation except for the measuring operation is made off line by using the function of the robot simulator. Further, a command of calling the measuring method with respect to the measuring portion, which has been set above, is added, so as to generate a robot program by the robot program generating means 94 of the computer 3 (step 207 ). After that, the processing is completed (step 208 ).
On the other hand, in the case where the measuring portion and/or the measuring method is judged not to be good, an alarm in which that the present setting is not appropriate (step 206 ) is given to the operator, the operator directs, whether the processing is continued or the processing is done over again. When the operator directs to continue the processing, the process is transferred to step 207 . When the operator directs to do the processing over again, the program is transferred to step 201 , so that the processing is redone from the very beginning. In this connection, a specific example of the judgment will be described later.
Next, processing (the function as a robot program analyzing device) to which the step numbers of 100 level are numbered, are explained. In this case, reference should be appropriately made to FIG. 12 which is a block diagram in the case where the computer is used as a robot program analyzing device.
First, a robot program is loaded to the robot simulator (step 101 ). For example, this robot program is a program made through the above processing. Alternately, this robot program is a program which was used in the actual system; however, trouble was caused in the system.
Next, from the loaded program, the robot simulator (the analyzing means 95 of the computer 3 ) analyzes which measuring portion of the work was measured and which measuring method was used (step 102 ). Then, the model of the work is displayed on the monitor 90 , and then the measuring portion and the measuring method, which were analyzed before, are displayed in the model on the monitor 90 by using the measuring portion display means 90 a and the measuring method display means 90 b (step 103 ). It is considered that the model to be displayed is a model of the designing data of CAD as in the case of step 201 . An image snapped by a video camera may be displayed instead of the model. In order to successfully overlay the model on the analyzed position, for example, the image plane at the time when this program was made by the robot simulator may be stored in another way.
Next, information about the work, namely work information, is designated (step 104 ). As described before, this work information is data in which the work size, the work material, the method of gripping the work and the state of loading the work have been previously coded. In step 104 , the operator appropriately combines and designates the work information.
Then, the measuring portion and/or the measuring method, which were analyzed, are judged by the judging means 93 (step 105 ). Concerning this judgment, in the same manner as that of the above step 205 , the judgment is made with the rule (the reference information) stored in the storage section 92 . In the case where it is judged to be good, the processing is finished as it is (step 107 ). In the case where it is judged not to be good, an alarm in which that the present program is not appropriate is given to the operator (step 106 ), and the operator directs whether or not the program is corrected. When the operator directs that the program is not corrected, the process is finished as it is (step 107 ). When the operator directs that the program is corrected, the process is transferred to step 201 , and the program is corrected by using the same process as that of generating the program.
As described above, according to the present invention, the measuring portion and the measuring method are judged to be good or not good in both the case of program generation (including the case of correction) and the case of program analysis. Therefore, this judgment whether it is good or not will be more specifically explained in the following descriptions.
Diagnosis on Measurement Error
Items to be checked here are described as follows. One item is whether or not the measuring method appropriate for a state of loading is selected. The other item is whether or not the appropriate measuring portion is selected from the viewpoint of comparison of the estimated measuring error with the allowable error which has been set. A specific work model (or an image) is shown in FIG. 3 . The entire work model shown on the image plane is represented by the reference mark W in FIG. 3 . The measuring portion (the image portion snapped by the video camera 2 in this case) represented by the reference mark M corresponds to the measuring portion designated in the above step 202 or “the analyzed measuring portion” in the above step 103 . Point M 0 is a point representing the measuring portion M, for example, Point M 0 is the gravity center of the image.
The work information is shown in the right half of FIG. 4 . The work information is designated in such a manner that numerical values or types with respect to the work size, the work material, the work gripping method and the work loading are designated by the manual operating section 91 . Concerning the work size, as shown in the left half of FIG. 4 being generalized, a rectangle coming into contact with the work model is found by means of image processing, and the length and width are determined in consideration of displaying magnification. The thus obtained numerical values are employed. In this connection, the numerical values 62 mm and 112 mm shown in FIG. 4 are merely examples.
Concerning the work material, the type of the material is designated in terms of whether it is a flexible material such as a thin metallic sheet or it is not a flexible material such as a casting. In this case, the former is designated as an example.
Concerning the gripping method of the work, in the case where there is a limit in the positional error (for example, the error of the detecting position of the point M 0 in FIG. 3 ) capable of being allowed at the time of positional detection conducted by the visual sensor or in the case where there is a limit in the inclination error (for example, the detection error of the inclination of the work W in FIG. 3 ) capable of being allowed, the operator inputs numerical values concerning these limits. In this connection, these numerical values are determined on the basis of the performance of the handling mechanism or hand. When the work can be positioned with a sufficiently large capacity of absorbing the error, the item “positioning mechanism in hand” is designated as exemplarily shown here.
Concerning the loading state of the work, the following three types are designated according to the irregularity of the way of putting the work. They are: “the displacement is within allowable error”, that is, the individual works are approximately accurately positioned; “the two-dimensional displacement exceeding the allowable error is caused”, that is, although the height positions are approximately the same, the positions on the plane are not definite; and “the three-dimensional displacement exceeding the allowable error is caused”, that is, the works are loaded in bulk. In this case, an example is taken up and designated in which “the three-dimensional displacement exceeding the allowable error is caused”.
FIG. 5 a and FIG. 5 b are flow charts showing an outline of the processing for conducting diagnosis of the measuring error. First, as the step of preparation, the number of points designated for the measurement is read in. Next, according to the content of the setting of the loading state included in the work information, the processing to be conducted after is classified (step 301 ). When the setting of the loading state is “the displacement is within the allowable error” (step 302 ), the process is finished as it is (step 319 ).
When the setting of the loading state is “the two-dimensional displacement exceeding the allowable error” (step 303 ), the gripping error is calculated from the previously estimated measurement accuracy and the work size (step 305 ). In this case, consideration may be given only to the positional error. The method of calculation will be described in another item 1 . The gripping error is compared with the allowable error (the limits of the positional error and the inclination error) which has been set in the setting of the gripping method (step 306 ). In the case where the gripping error is not larger than the allowable error, the process is finished as it is (step 319 ). In the case where the gripping error is larger than the allowable error, the process proceeds to step 307 , and it is judged whether or not the second measuring portion is present. Unless the second measuring portion is present, the error flag 2 is set (step 318 ) and the processing is finished (step 319 ).
When the second measuring portion is present, the maximum gripping error at the time of gripping both end portions of the work is calculated from the positions of the first and the second measuring portion (the representative points), the accuracy of measurement and the work size (step 308 ). An example of the method of calculation will be described later in another item 1 . The gripping error is compared with the allowable error (the limits of the positional error and the inclination error) which has been set in the setting of the gripping method (step 309 ). When the gripping error is not larger than the allowable error, the process is finished as it is (step 319 ). When the gripping error is larger than the allowable error, after the error flag 2 is set (step 318 ), the processing is finished (step 319 ).
In the case where the setting of the loading state is “the three-dimensional displacement exceeding the allowable error” (step 304 ), it is checked whether or not the measuring method of the first measuring portion is 3D measurement (the three-dimensional measurement) (step 310 ). When the measuring method of the first measuring portion is not 3D measurement (the three-dimensional measurement), that is, when the measuring method of the first measuring portion is 2D measurement, the error flag 1 is set (step 311 ), and the maximum gripping error at the time of gripping both end portions of the work is calculated from the previously estimated measuring accuracy and the work size (step 312 ). In the case where the measuring method of the first measuring portion is 3D measurement, the error flag 1 is not set and the process proceeds to step 312 and the gripping error is calculated in the same manner. In this case, it is necessary to diagnose both the positional error and the inclination error. An example of the method of calculation will be described in another item 2 .
Next, the gripping error is compared with the allowable error (the limits of the positional error and the inclination error) which has been set in the setting of the gripping method (step 313 ). When the gripping error is not larger than the allowable error, the process is finished as it is (step 319 ).
When the gripping error is larger than the allowable error, the presence of the measuring portions after the second point is checked for (step 314 ). When the measuring portions after the second point are not present, the error flag 2 is set (step 318 ) and the processing is finished (step 319 ). When the gripping error is larger than the allowable error and further the measuring portions after the second point are present, it is checked whether or not the measuring method of these measuring portions is 3D measurement (step 315 ). When either of the measuring methods of these measuring portions is not 3D measurement, the error flag 2 is set (step 318 ) and the processing is finished (step 319 ). When all of the measuring methods of these measuring portions are 3D measurement, with respect to these points, the maximum gripping error at the time of gripping both end portions of the work is calculated from the previously estimated measuring accuracy and the work size (step 316 ).
The gripping error is compared with the allowable error (the limits of the positional error and the inclination error) which has been set in the setting of the gripping method (step 317 ). When the gripping error is not larger than the allowable error, the process is finished as it is (step 319 ). When the gripping error is larger than the allowable error, after the error flag 2 is set (step 318 ), and the processing is finished (step 319 ).
As described above, the diagnosis made for the measuring error is completed. When neither the error flag 1 nor the error flag 2 is set, the result of the diagnosis is “good”. When either the error flag 1 or the error flag 2 is set, the result of the diagnosis is “not good”.
Diagnosis Made for Displacement
In the case where the work and the hand are displaced from each other after the work has been gripped by the hand, although the work has been correctly gripped, there is a high possibility of the occurrence of trouble when the work is conveyed to the next process. Therefore, the diagnosis is conducted according to the procedure shown in the flow chart of FIG. 6 . That is, it is judged whether or not “The positioning mechanism is provided in the hand.” (shown in FIG. 4 ) of the gripping method is set (step 401 ). When it is set, the process is finished as it is (step 403 ). When it is not set, the error flag 3 is set (step 402 ) and then the process is finished (step 403 ).
Diagnosis Made for Influence of Deflection of Work
For example, in the case a work is a thin metallic sheet, its peripheral portion is likely to deflect. This deflection causes an error which cannot be estimated as far as it is measured every time. Therefore, the possibility of the occurrence of the influence caused by the deflection will be diagnosed by the procedure shown in the flow chart of FIG. 7 .
It is judged whether or not “It is easily deflected.” is selected in the setting of the work material (step 501 ) (shown in FIG. 4 ). When “It is easily deflected.” is not selected, the processing is finished (step 505 ). When “It is easily deflected.” is selected, it is judged whether or not the work size is larger than a predetermined value (step 502 ). Concerning the judging method, the length and width of the work may be compared with the respective predetermined values (the previously set upper limits). Alternatively, the numerical value of (length)×(width) may be compared with its upper limits. When the numerical value is not the predetermined value, the processing is finished (step 505 ).
In the case where the work size is larger than the predetermined value, with respect to all the measuring portions, it is judged whether or not these measuring portions are close to the peripheral portion of the work (step 503 ). For example, with respect to all the measuring portions, it is judged whether or not the distances from the edge line are shorter than a predetermined value (a previously set lower limit). When the distances from the edge line are longer than the predetermined value, that is, all the measuring portions are distant from the peripheral portion, it is judged that these measuring portions are seldom affected by the deflection, and the processing is finished (step 505 ). When the distances from the edge line are shorter than the predetermined value, that is, all the measuring portions are close to the peripheral portion, it is judged that these measuring portions are likely to be affected by the deflection, and the error flag 4 is set (step 504 ), and the processing is finished (step 505 ).
Next, referring to the flow chart of FIG. 8 , an outline of the flow of the entire diagnosis including the above diagnosis will be explained below.
First of all, all error flags are cleared (step 601 ). Next, the data of measurement accuracy, which is previously estimated, is loaded (step 602 ). Successively, the diagnosis with respect to the measurement accuracy (step 603 ), the diagnosis with respect to the gripping displacement (step 604 ) and the diagnosis with respect to the measuring portion (the diagnosis of deflection) (step 605 ) are executed. Since the contents of these diagnoses have been explained before, the explanations are not repeated.
After all the diagnoses have been completed, the results are displayed. That is, it is successively checked whether or not the error flags 1 to 4 are set (steps 606 , 608 , 610 , 612 ). When the error flags are set, the corresponding messages are displayed on the monitor 90 (steps 607 , 609 , 611 , 613 ) and the processing is finished.
That is, when the error flag 1 is set, this means that 2D measurement was made at a portion where 3D measurement should be originally made. In the case where this portion is the point A, for example, the message that “The point A was not measured by 3D measurement.” is displayed.
When the error flag 2 is set, this means that the measurement accuracy is not satisfied at the present measuring portion. Therefore, for example, the message that “Keep the measuring portion away from the present position.” is displayed.
When the error flag 3 is set, this means that although the work has been gripped, there is a possibility the work is displaced before it is put in the process conducted later. Therefore, for example, the message that “Correct the displacement of the work again with the visual sensor before it is put, or arrange a positioning mechanism in the hand.” is displayed.
When the error flag 4 is set, this means that there is a possibility that an error, which can not be estimated, is caused each time in the measuring portion. Therefore, the message that “Keep the measuring portion farther away from the peripheral portion.” is displayed.
Finally, referring to “another item 1 ” and “another item 2 ” which are described below, the method of calculating the maximum gripping error in the above steps 305 , 312 and so forth (shown in FIG. 5 ) will be explained.
Another Item 1
As shown in FIG. 9 , the higher numerical value in the numerical values of the length and the width of the work is represented by “a” in the setting of the work size. Suppose that the estimated measurement error includes the positional error E p and the rotation (inclination) error E r . The gripping error caused by the measurement error actually depends on the measuring portion and the gripping portion. However, in this case, the problem is simplified as follows. In the case where the measuring portion is located on one side of the work, on the assumption that the hand grips an end of the opposite side of the work, an error generated in this case is estimated. In most cases, the error found on this assumption is larger than the substantial gripping error. Therefore, when this error is used for the comparison of the allowed error, no problems are caused. In this connection, only the two-dimensional error is referred in this case. Therefore, this explanation of the error has no relation with the inclination error.
(1) In the Case of Only One Measuring Portion
When the gripping position is P (vector) in the case where no error is caused in the measurement and the gripping position is P′ (vector) in the case where an error is caused in the measurement, and when consideration is given to that the rotation error Er is very small, the value to be found can be expressed by the following expression.
| P−P′|=|E p |+a|E r |
In this connection, the mark | | expresses an absolute value.
(2) In the Case of a Plurality of Measuring Portions
A set of a plurality of portions, the distance between which is the longest, are selected, and the distance is expressed by D. In the same manner as that of the above item ( 1 ), when the gripping position is P in the case where no error is caused in the measurement and the gripping position is P′ in the case where an error is caused in the measurement, only E p is related here. The value to be found can be expressed by one of the following expressions.
| P−P′|=|E p |(2 a/D− 1) and | P−P′|=|E p |
The higher numerical value in the numerical values expressed by the above expressions is a value to be found.
Another Item 2
As shown in FIG. 10 , the higher numerical value in the numerical values of the length and the width of the work is represented by “a” in the setting of the work size. Suppose that the estimated measurement error includes the positional error E p , the inclination error E i and the rotation error Er. In the same manner as that described in another item 1 , the gripping error caused by the measurement error actually depends on the measuring portion and the gripping portion. However, in this case, the problem is simplified as follows. In the case where the measuring portion is located on one side of the work, on the assumption that the hand grips an end of the opposite side of the work, an error generated in this case is estimated. In most cases, the error found on this assumption is larger than the substantial gripping error. Therefore, when this error is used for the comparison of the allowed error, no problems are caused.
The inclination error is related to a case in which although the position is accurate, the hand can not successfully grip the work unless the gripping motion of the hand is conducted perpendicularly to the work face. From the above definition, the inclination error is |E i |.
(1) In the Case of One Measuring Portion
When the gripping position is P in the case where no error is caused in the measurement and the gripping position is P′ in the case where an error is caused in the measurement, and when consideration is given to that the inclination error E i and the rotation error E r are very small, the value to be found can be expressed by the following expression.
| P−P′|=|E p |+a {( E r ) 2 +( E i ) 2 } 1/2
(2) In the Case of a Plurality of Measuring Portions
A set of a plurality of portions, the distance between which is the longest, are selected, and the distance is expressed by D. When the gripping position is P in the case where no error is caused in the measurement and the gripping position is P′ in the case where an error is caused in the measurement, only E p is related to the maximum gripping error. The value to be found can be expressed by one of the following expressions.
| P−P′|=|E p |(2 a/D− 1) and | P−P′|=|E p |
The higher numerical value in the numerical values expressed by the above expressions is a value to be found.
Although the invention has been shown and described with exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto without departing from the spirit and the scope of the invention.
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A work model (or an image) is displayed on an image plane of a robot simulator ( 201 ), and a measuring portion and a measuring method are designated ( 202, 203 ) and a work shape and a work loading state are designated ( 204 ), and then it is judged whether or not the measuring portion and the measuring method are good ( 205 ). When the measuring portion and the measuring method are good, a program is generated and the processing is completed ( 207, 208 ). When the measuring portion and the measuring method are not good, an alarm is given ( 206 ), and the continuation ( 207 ) or the repetition ( 201 ) of the processing is directed. At the time of analyzing the program, the loading ( 101 ), the analysis and display of the measuring portion and the measuring method ( 102, 103 ) and the work information ( 104 ) are designated, and then it is judged whether or not the measuring portion and the measuring method, which have been analyzed, are good ( 105 ). When the measuring portion and the measuring method are good, the processing is finished ( 107 ). When the measuring portion and the measuring method are not good, an alarm is given ( 106 ), and either the completion of the processing ( 107 ) or the correction of the program ( 201 ) is selected. Due to the foregoing, a burden imposed for raising and maintaining the visual sensor robot system can be reduced.
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CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/460,527, filed Apr. 4, 2003.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to card games and more particularly to a modified version of blackjack that involves some or all of the players placing an additional wager at the beginning of a hand.
[0003] Blackjack (also known as twenty-one) is a common playing card game in which one or more players play against a dealer. The players play individually against the dealer, not against one another. Each player's objective is to hold a hand of two or more cards having a count closer to 21 (without going over) than the count of the dealer's hand. In determining the count of a hand, cards numbered 2-9 are assigned a rank equal to their respective face value, 10's, jacks, queens, and kings are assigned a rank of 10, and aces are assigned a rank of 1 or 11, at the player's option.
[0004] Blackjack is often played in casinos where each player places a wager on the outcome of a hand against the house. Wagers are placed at the beginning of the hand, before any cards are dealt. Play then begins with the dealer dealing two cards to each player and himself. Each player then is given the opportunity to “hit” (take an additional card) in an attempt to achieve a count closer to 21. The player can elect to “stand” (decline to take more cards) at anytime if satisfied with his or her count or concerned that another card will result in a “bust” (i.e., a count exceeding 21). Players can also exercise certain options such as “doubling down,” “splitting pairs,” and “surrender” in given situations. After all of the players have elected to stand on their hand, the dealer plays out his or her hand based on pre-established rules for the game. Typically, if the dealer has less than 17, the dealer must take a hit. If the dealer has 17 or more, the dealer stands.
[0005] A player wins the wager against the house if his or her count is closer to 21 than the dealer's count; the player loses the wager if the dealer's count is closer to 21 than that player's count. Any player that busts loses regardless of the final count of the dealer's hand. If a player's and the dealer's counts are the same (without exceeding 21), no one wins and the hand is called a “push.” Any player receiving a “blackjack” (i.e., a two-card hand having a count of 21, also referred to as a natural) wins at once, unless the dealer is also dealt a blackjack. Blackjacks are typically paid off at one and a half times the wager.
[0006] While conventional blackjack is considered by many to be an exciting game, all players play against the dealer only and not among themselves. Furthermore, there is only one wagering opportunity during the course of each deal. Thus, if a player busts early in a hand and thus loses automatically, he or she has no further interest in that deal and must wait idly while the other players and the dealer play out their hands. Accordingly, it would be desirable to have a modified version of blackjack in which players could play among themselves as well as against the dealer and place additional wagers that could maintain interest in a deal after a player's hand has played out.
SUMMARY OF THE INVENTION
[0007] The above-mentioned need is met by the present invention, which provides a method of playing a card game based on the standard blackjack game but played with an added twist that involves some or all of the players at a blackjack table joining in placing an additional bet or a side wager in an attempt to beat every other player at the table and the dealer. This option of placing an additional bet in anticipation of having the “highest” hand at the table adds the excitement of having an opportunity to win a much larger “pot” as well as bringing friendly competitiveness to the table. Pots that are “pushed” will grow rapidly and even a player that loses his or her hand against the dealer can still be involved in the next deal of the game.
[0008] The present invention and its advantages over the prior art will be more readily understood upon reading the following detailed description and the appended claims with reference to the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
[0009] The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the concluding part of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:
[0010] FIG. 1 shows a gaming table based on a traditional blackjack table and having additional features that facilitate playing the game of the present invention.
[0011] FIG. 2 shows another version of a gaming table that can be used to play the game of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] In one embodiment of the present invention, play begins with each player placing a wager on the outcome of his or her hand against the dealer, just as is done in conventional blackjack. The amount of this wager is at the player's option, limited only by any house limits that may be in effect. Each player, at his or her option, can also place an additional or side wager of a pre-determined amount for each table ($5 for this example, but any amount could be used), by presenting the dealer a betting chip that the dealer places on a designated spot in front of the dealer which corresponds to the player's seat at the table. As shown in FIG. 1 , a table 10 is provided with a layout that has seven player positions, by way of example. The table layout includes a betting square 12 for each player position that receives the player's blackjack wager. The table layout may have an additional circle spot 14 for each table seat, for receiving the player's side wager, as well as another circle spot 16 which will receive the dealer's side wager. It should be noted that the shapes of the betting squares 12 and the circle spots 14 , 16 are not limiting as these features can take other shapes. An alternative method of displaying and/or handling the player's side wager in the present invention is to have a special “chip display” or jackpot container located in front of the dealer that holds all bets associated with the side wager.
[0013] All wagers are placed at the beginning of the hand, before any cards are dealt. Thus, after the conventional blackjack wagers have been placed and before a hand is dealt, the players at the table 10 are asked if they would like to compete in the side wager. Those that respond positively will give the dealer a $5 chip to be placed on his or her related circle spot 14 . The dealer will then place a $5 chip from the casino chip rack on the dealer's circle spot 16 . Any player that does not place a $5 wager before a hand of cards is dealt is declared ineligible for that round of the side wager and cannot participate in the side wagering until the beginning of another round. Before the dealer deals the first of perhaps several hands of the game, a two-sided “puck” is placed before the circle spots discussed above to indicate that a round of side wagering is in progress and no new players may participate in the ongoing side wagering round until a winner is declared (similar to the roll-out “number” at craps). In this embodiment, the side wager aspect of the game of the present invention is optional. Thus, the game can accommodate players who wish to play conventional blackjack only, while allowing other players to partake in the side wagering. Alternatively, a table 10 can be designated as being dedicated to the side wagering, in which case all players at the table are required to participate in the side wagering. In this case, a single puck 18 can be used to indicate that a round of side wagering is in progress, as shown in FIG. 2 . FIG. 2 also shows a jackpot container 20 used to hold the side wagers instead of the player and dealer circle spots.
[0014] Once all wagers have been made, play proceeds in normal blackjack fashion with each player and the dealer being dealt two cards. After the initial deal, each hand is played out with respect to the conventional blackjack wager and paid off as usual. That is, each player “hits” and/or “stands” to achieve a count as close to 21 as possible without busting. Players can also exercise certain options such as “doubling down,” “splitting pairs,” and “surrender” in given situations. After all of the players have elected to stand on their hand, the dealer plays out his or her hand based on pre-established rules for the game.
[0015] With respect to the side wager pot, the goal of the participating players and the dealer is to have the highest final hand count at the table for that deal. Before all the completed hands are removed from the table the dealer will determine which position at the table, including the dealer's, had the highest count without busting. Should a player or the dealer stand alone with the highest hand count without busting, they shall be declared the winner and receive all the monies on all the special circle spots or in the jackpot container (i.e., the entire side wager pot). At this point the puck shall be turned over indicating a new round of side wagering is beginning.
[0016] If, as will be the case in many instances, there are two or more hands at the table that are tied with the highest count, including the dealer's, a “push” is declared, meaning that the side wager pot is not awarded and all players participating in the side wager must place an additional $5 chip before the dealer to be placed on his or her appropriate circle spot to continue competing for the side wager pot. (If a player elects to not put in an additional chip, then he or she will no longer compete for the side wager pot and forfeits all money previously put into the current side wager pot.) The dealer must also place another $5 chip in the designated dealer circle spot, after which another hand of cards is dealt. Hands are continued in this fashion until the side wager pot is awarded, at which point a new round of side wagering can start.
[0017] Whenever a player participating in the side wager chooses to double down or split pairs he or she will be required to present another chip ($5 in this example) to the dealer to be placed on his or her designated circle spot. Every new hand that develops because of doubling down or splitting pairs will require an additional $5 payment to the side wager jackpot for the round of play. In the case of a player splitting pairs and receiving the highest hand count at the table with both hands, that player will win the side wager pot. In other words, a player that has split pairs cannot push himself.
[0018] The dealer plays along with the players in the side wager and must compete with their results head on. However, whenever the dealer alone receives a “blackjack” (i.e., a two-card hand count of twenty-one) the round of side wagering is automatically over with the dealer declared the winner of the side wager pot, even if one or more of the players receives a hand count of twenty-one with three or more cards. This automatic win for the dealer via a blackjack represents the casino vigorish for the side wager. An alternative approach to providing the casino vigorish for the side wager is to give the dealer/casino a predetermined percentage (such as 5 percent) of each side wager pot.
[0019] Other than the dealer automatically winning when he is the only one to receive a blackjack all other winning hands are decided on the card counts, even if one or more players has a blackjack. In other words, a player blackjack is treated as a hand count of 21 and will result in a “push” in the side wager if just one other player or the dealer has a resulting hand count of 21.
[0020] The present invention provides a variation of blackjack that can be played in many environments. As described above, the game is played live in casinos with a dealer. However, the game can also be played live by two or more people in non-casino environments such as a home. The game can also be played from a variety of locations in interactive electronic or video form. In addition to being played live with actually playing cards, the game can be played electronically via video game machines, home computers and the like.
[0021] While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention as defined in the appended claims.
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A method of playing a modified version of blackjack between participants including a dealer and one or more players. The method includes the steps of each player placing a first wager to participate in a standard blackjack game against the dealer, and each player and the dealer placing a side wager into a side wager pot. The dealer then deals a two-card hand to each player and a two-card hand to the dealer and each hand is played out according to standard methods of playing blackjack. The method further includes awarding the side wager pot to the participant, if any, having a final hand count that is higher than all other final hand counts without exceeding twenty-one.
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BACKGROUND OF THE INVENTION
The invention pertains to a heating device for a corrugated cardboard facility and, more particularly, to such a heating device having several heating plates arranged sequentially in the advancing direction of the sheet of corrugated cardboard, and also having compression elements arranged above the heating plates for acting on the sheet of corrugated cardboard.
Such a device in a corrugated cardboard facility has the function of drying glue between superimposed sheets, for example, one-sided sheets of corrugated cardboard and finally the cover sheet.
To this end, known devices have heating plates that are heated, for example, with steam or thermal oil. By means of a continuous transport belt, the sheet is conveyed through the heating zone. Compression elements press the sheets of corrugated cardboard against the surface of the heating plates in order to achieve an appropriate contact of the sheets of corrugated cardboard with the surface of the heating plates, that is, a good transfer of heat to the glue line.
In the case of one known compression unit shown in U.S. Pat. No. 5,632,830, weighted rollers are also used, which are affixed by intervening levers to a bearing arranged transversely to the advancing direction of the sheet of corrugated cardboard.
Further state of the art is also a compressing unit in the form of a pressure plate consisting of several units extending along the sheet of corrugated cardboard as shown in Canadian Patent No. 2,197,921. Also known is the use of pressure hoods shown in European Patent Publication EP 0,412,255 A1, as well as rollers shown in U.S. Pat. No. 5,632,830, which exert pressure on a circulating conveyor belt.
In order to avoid the disadvantages of the transport belt, it is also state of the art, as shown in U.S. Pat. No. 5,632,830, that the transport belt is eliminated and the sheet of corrugated cardboard is pressed directly against the heating surfaces by compression elements.
When the transport belt is dispensed with, however, automatic intake of the introduced sheets is no longer possible. Furthermore, eliminating the transport belt results in increased friction with the cardboard, and this increased friction produces frequent tears in the cardboard as it passes through the heating zone. Tears in conjunction with troublesome reinsertion bring about unacceptable production losses.
SUMMARY OF THE INVENTION
Accordingly, the basic objective of the present invention is to create a corrugated cardboard heating device in which the sheets of corrugated cardboard arriving from preceding parts of the facility are drawn in and automatically advanced through the beltless part of the heating device.
This objective is realized according to the invention, in that an intake belt is located in the starting area of the heating plates between at least a part of the sheet of corrugated cardboard and at least one compression element. With the aid of this intake belt it is possible to join together functionally securely the individual layers of the corrugated cardboard and also to compensate for any possible frictional losses of the preceding facility sections.
The intake belt can be designed as a conveyor belt running over two physically separated deflection rollers. Here there exists the possibility that the conveyor belt is acted upon by at least one compression element oriented in the advancing direction of the sheet of corrugated cardboard. Furthermore, the intake belt can be designed to be heated.
For good adaptation to the given conditions, it is possible that the distance between the two deflection rollers be variable. Here the rear deflection roller can be designed to be displaceable in the running direction of the sheet of corrugated cardboard with the conveyor belt running over an adjustable tension roller.
According to one embodiment form of the invention, the possibility exists that all of the layers of the sheet of corrugated cardboard can be affected by the compression elements acting on the conveyer belt. Alternatively, it is also feasible, for example, with three layers of the sheet of corrugated cardboard, that the compression elements acting on the conveyor belt initially affect only two layers of the sheet of corrugated cardboard and that the third layer be added to the sheet of corrugated cardboard behind the second deflection roller. This third layer can, for example, be transported by a feeder roller.
In order to achieve a more rapid gluing, heatable compression elements can be provided in front of the feeder roller.
A particularly simple embodiment of the invention results when the heating device is designed with an upper and a lower intake roller in the initial area of the heating plates. In this case, the upper intake roller can also serve as the first deflection roller for the conveyor belt.
In a further refinement of the invention, the feeder roller can also be designed to be heatable.
These and other objects, advantages, and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side view of a first embodiment of the invention.
FIG. 2 is a schematic side view of an alternative embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Illustrated in FIG. 1 is a heating device 1 for a corrugated cardboard facility. Heating device 1 consists of several heating plates 3 arranged sequentially in the advancing direction of the sheet of corrugated cardboard 2 and arranged above them, compression elements 4 acting on the sheet of corrugated cardboard 2. The sheet of corrugated cardboard 2 can consist of several layers, for example, a one-sided sheet of corrugated cardboard "a", another one-sided sheet of corrugated cardboard "b" and a cover sheet "c".
The compression elements 4 can be of any desired design, for example, a pressure hood, weighted rollers, or pneumatically charged compression units.
The sheet of corrugated cardboard 2 runs from a starting area "A" of the heating plates 3 to a tractor station 30 in the end area, which undertakes the cooling of the glued sheet of corrugated cardboard 2 by way of conveyor bands, rollers 11' and 11" as well as 12' and 12", tension rollers 13' and 13" as well as compression elements 4, and furthermore serves to transport the sheet and to compensate for the high friction losses, especially in the case of a beltless heating section.
According to the invention, an intake belt "E" is positioned in the starting area "A" of the heating plates 3 between at least a part of the sheet of corrugated cardboard 2 and at least one compression element, in this case two such elements 4.1 and 4.2. This intake belt "E" can be designed as a conveyor belt 10 running over at least two physically separated deflection rollers 11 and 12. This conveyor belt 10 can be heated, for example, by way of deflection rollers 11 and 12.
In the embodiment of the invention shown in FIG. 1, the conveyor belt 10 is acted on by at least two compression elements, compression elements 4.1 and 4.2 arranged sequentially in the running direction of the sheet of corrugated cardboard.
As can be seen in FIG. 1, an upper intake roller "O" and a lower intake roller "U" are present in the starting area "A". Here it is possible that the upper intake roller "O" also forms the first deflection roller "11" for the conveyor belt "10".
As indicated in broken outline in FIG. 1, it is possible to vary the distance between the two deflection rollers 11 and 12, for example, in that the rear deflection roller 12 is designed to be displaceable in the running direction of the sheet of corrugated cardboard 2. Here adjustable tension roller 13 is especially advantageous, whereby assurance is given that when the separation of the two deflection rollers is changed, the conveyor belt 10 always remains tautly tensioned.
In the embodiment of the invention according to FIG. 1, all three layers ("a", "b" and "c") of the sheet of corrugated cardboard 2 are acted upon by the conveyor belt 10 and the two compression elements 4.1 and 4.2 in the starting area A.
According to FIG. 2, it is also possible that only two layers, namely "b" and "c", are acted upon by the conveyor belt "10", which itself again runs over two deflection rollers 11 and 12. The third layer "a" is introduced via a feeder roller 20 behind the second deflection roller 12. Accordingly, a complete sheet of corrugated cardboard 2 is formed, which is in turn acted upon by the aforesaid compression elements 4, and runs over the surface of the heating plates 3. At least one heatable compression element 25 can be provided between the deflection roller 12 and the feeder roller 20.
By virtue of the present invention, assurance is given in a simple manner that the layers ("a", "b" and "c") to be glued are so joined together that an adequately stiff sheet of corrugated cardboard 2 is formed, which can be automatically threaded into the corresponding heating section with the heating plates 3.
The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the following claims.
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A heating device (1) for a corrugated cardboard facility includes several heating plates (3) arranged sequentially along a path in the advancing direction of a sheet of corrugated cardboard (2). Compression elements (4) are arranged above the heating plates (3) in position to act on the sheet of corrugated cardboard (2) as it advances along the path. An intake belt (e) is located in a starting area (a) of the heating plates (3) between at least a part of the sheet of corrugated cardboard (2) and at least one compression element (4.1, 4.2).
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process of preparing 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximidamide! having greatly reduced impurities therein useful in a method of treating cancer or advanced malignant diseases.
2. Reported Developments
The compound 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximide! is known by several names, such as 1,1' (methylethanediylidene)dinitrilo! diguamidine, pyruvaldehyde bis (amidinohydrazone), mitoguazone and methylglyoxal bis-guanylhydrazone, methyl GAG or MGBG, represented by the formula ##STR1##
MGBG and its salts have been disclosed in the prior art since the 1950s for use against various diseases as illustrated by the following patents and publications.
The antitumor activity of MGBG in leukemia-L1210- and adenocarcinoma-755-bearing rodents was first reported by Freelander et al, 18 Cancer Res. 360 (1958).
Japanese 51044643 discloses MGBG and its acid addition salts as effective agents against virus diseases of fishes to prevent and treat infections, pancreatic necrosis and hematopoietic necrosis.
Japanese 50029520 discloses MGBG and its salts for use against influenza virus.
U.S. Pat. No. 4,201,788 discloses MGBG for the treatment of non-malignant proliferative skin diseases.
MGBG is known to inhibit S-adenosylmethionine decarboxylase (SAMD), which is a key enzyme in polyamine synthesis, leading to cellular polyamine depletion. However, investigations with MGBG revealed unacceptable levels of toxicity. The toxicological effects of MGBG observed, some of which are peculiar to certain animal species, include gastrointestinal toxicity, delayed and fatal hypoglycemia, hepatic and renal damage, bone marrow depression, diarrhea and phlebitis. These effects have also prevailed in human subjects undergoing MGBG treatment. Additionally, several toxic effects were demonstrated which are unique to man. These include esophagitis, ulcerative pharyngitis, laryngitis, stomatitis, genital mucosa swelling, conjunctivitis, mucositis, erythema, edema, desquamating dermatitis, and profound anorexia with associated weight loss. Patients who were administered MGBG on a daily schedule exhibited remission to acute leukemia only after a precarious struggle with the oftentimes life threatening side effects. In many patients, treatment had to be discontinued before any beneficial results could be noted.
Knight et al in Can. Treat. Rep., 63 1933-1937 (1979) found that the levels of toxicity were dose schedule related and could be controlled. U.S. Pat. No. 4,520,031 addresses the issue of such dose schedule related control in order to reduce toxicity.
The dose schedule control, as described in the patent was based on the postulation that MGBG exerts an inhibitory action relative to polyamine biosynthesis. Physiologically achievable effects of MGBG may be related to the inhibition of the enzyme S-adenosyl methionine decarboxylase, which catalyses the synthesis of the polyamine, spermidine.
Spermidine is believed to play an important role in the initiation of DNA synthesis. Studies have shown that MGBG-mediated depression of DNA synthesis is associated with spermidine depletion and putrescine accumulation.
Another area in which polyamines are believed to play a major role is in RNA synthesis, especially that of transfer (t) RNA. The methylation of tRNA may be directly stimulated by polyamines, a finding of particular interest in light of the reports that neoplastic tissue differs from normal tissue with respect to the extent of methylated tRNA. Here, too, spermidine appears to play a critical role.
Polyamine accumulation appears to be a necessary requisite to DNA synthesis at an optimal rate, in both normal and neoplastic tissues. Thus, the toxicity of MGBG observed in tissues with rapid turnover (skin, G.I. mucosa and bone marrow) may be directly related to inhibition of polyamine biosynthesis and a subsequent depletion of RNA and DNA, the agents which ultimately regulate cell replication. There is, however, strong evidence that: (1) polyamines are excreted in excess in the majority of cancer patients; (2) polyamines, especially spermidine, are released from tumor cells during and after effective chemotherapy, with an initial peak in excretion and in serum levels and subsequent drop toward normal values; and (3) chemotherapy which produces only bone marrow (or other normal tissue) toxicity, and is without antitumor effectiveness, does not produce a significant increase in polyamine excretion. The latter observation would suggest either that cancer cells have much higher levels of polyamines than normal cells, even those with higher rates of DNA synthesis, or that therapy which is effective produces rather specific effects on polyamine synthesis in cancer cells. Thus, the depletion of spermidine is associated with the action of MGBG.
In studies conducted on men, toxicological effects observed clinically have been attributed to cumulative effects of repeated daily doses. This cumulation or accretion of toxicity is possibly explained by the unusually prolonged period required for urinary elimination of MGBG in man. Bioavailability studies in man with MGBG-C 14 have shown that following a single intravenous infusion over a period of 20 minutes, the radioactivity rapidly disappeared from the plasma and that over an extended period of 3 weeks approximately 60 percent of the drug was excreted unchanged in the urine. These data suggest that MGBG accumulates in the tissues and is slowly leached from tissue deposits to accomplish elimination.
The patentee, after considerably large number of studies conducted with MGBG in the treatment of various tumors, concludes that a weekly schedule of administration is most effective in achieving a higher therapeutic index while reducing toxicity to an acceptable level. Accordingly, a dose range of from 250 mg/m 2 to 1000 mg/m 2 of MGBG administered at weekly intervals was established for the treatment of various tumors.
While the above-indicated dose range decreases toxicological side effects and affords treatments of various tumors, long term accumulation of MGBG is still a problem requiring further studies and/or treatment modifications.
Applicants have conducted extensive studies of MGBG with the object to further reduce toxic side effects thereof. In the course of their studies it was discovered that MGBG contains relatively large mounts of impurities which may contribute to the toxicological side effects of MGBG. Accordingly, great efforts were expended to identify and reduce the amount of impurities present in MGBG and its salts.
The process of preparing guanylhydrazones is described by Baiocchi et al., J. Med. Chem., 6, 431 (1963) and Oliverio, Denham, J. Pharm. Sci., 52, 202 (1963).
The process comprises reacting of an aminoguanidine salt with the corresponding carbonyl compound in an aqueous or aqueous-alcohol medium in the presence of a catalytic amount of acid.
The process uses commercially available aminoguanidine bicarbonate and is described as follows.
General Preparation of Guanylhydrazones
To a solution of 0.11 mole (15 g) of aminoguanidine bicarbonate in 125 mL of water was added slowly to the desired acid (a few drops of amyl alcohol was added in order to prevent foaming) until the pH of the solution was less than 7. The solution was filtered from trace amounts of insoluble solids. The appropriate carbonyl compound was then added to the slightly acid filtrate at ca 60° C. The amount of carbonyl compound used was such that the ratio of aminoguanidine per carbonyl function was 1:1. If the carbonyl compound did not dissolve in the aqueous mixture, ethanol was added until the reaction mixture was homogeneous. The solution was then stirred at room temperature for 16 hours. If a precipitate was formed the solid product was isolated by filtration. Otherwise the reaction mixture was evaporated until a solid residue was obtained using methanol, ethanol and a combination of solvents.
Recovery of guanylhydrazones was low.
In addition of low yield we have found that the products contained relatively large amounts of impurities.
Experimental
We have developed methods for analysis of mitoguazone dihydrochloride using various systems to identify and quantify its impurities. One system of analysis included High Performance Liquid Chromatography. Considered in terms of determining chromatographic impurity levels, a high degree of specificity provides confidence that all the potential species of interest are detectable. Where these species, including process impurities and degradation products, are not available to inject directly onto the chromatographic system, specificity testing is usually conducted on stressed samples using one or more techniques which can usually be placed in one of two broad categories:
(a) Use of a specialized detection system to extract further information from the analyte peak.
(b) Some form of comparison between complimentary separation techniques, the first being the system under validation and the second being a system which, by virtue of its differing selectivity, might be expected to resolve species co-eluting in the first instance.
Examples of techniques in the first category include the use of diode array and mass spectroscopy detectors to obtain UV/Visible or mass spectra respectively from various positions through the analyte peak allowing, potentially, for the detection of co-eluting species. Techniques in the second category include the use of flow switching apparatus to divert the analyte peak onto a second stationary phase with a different selectivity, or comparison of results from the system being validated with those from a second chromatographic technique such as Thin Layer chromatography (TLC).
Equipment and Chemicals
HPLC data were generated using various Kontron (Watford, Herts) and Waters (Watford, Herts) pump, autosampler, column oven and detector models. HPLC data were processed using Multichrom™ V1.8-2 (LabSystems, Altringham, Cheshire). UV/visible absorption spectra were captured using an HP 1040 diode array detector (Hewlett Packard, Bracknell, Berks.). Light stressing (Xenon source, filtered through window glass) was performed in a Haraeus Suntest™ (Alplas Technology, Oxford). HPLC grade acetonitrile was obtained from Rathburn chemicals (Walkerburn, Scotland), HPLC grade heptane sulphonic acid (sodium slat), and inorganic chemicals were obtained from BDH limited (Poole, Dorset). ACVA (4,4'-Azobis(4-cyanovaleric acid), a radical initiator, exposure to which mimics oxidative stress, was obtained from Aldrich (Gillingham, Dorset). Mitoguazone dihydrochloride and purified water were obtained in-house.
Stress Sample Preparation
Samples of mitoguazone dihydrochloride (approximately 370 mg, equivalent to 250 mg base) were accurately weighed into 50 mL volumetric flasks and stressed according to the conditions given below. Stressing was continued for a maximum of 7 days or until 20 to 50% degradation had been achieved. After stressing, samples were neutralized, if necessary, and diluted to volume with purified water to give ˜5 mg(base)/mL solutions for TLC analysis. Aliquots of these solutions were diluted with purified water to give ˜1 mg(base)/mL solutions for use in impurity determinations by HPLC. Finally, aliquots of these solutions were either diluted in HPLC mobile phase to give ˜0.01 mg(base)/mL solutions for HPLC assay.
Stress Conditions
Heat: Sample held at 80° C. for 7 days. Acidic: 10 mL of 0.1M hydrochloric acid was added to the sample and the solution held at 70° C. for 7 days. Basic: 10 mL of 0.1M sodium hydroxide was added to the sample and the solution held at 70° C. for 2 days. Aqueous: 10 mL of purified water was added to the sample and the solution held at 70° C. for 7 days. Oxidative: 10 mL of a 0.1M aqueous ACVA solution was added and the sample held at 40° C. for 7 days. Light: Sample received an overall illumination of ˜15,000 klx hours (with associated UV). Assay: Samples were chromatographed isocratically on a 25 cm×0.46 i.d. Hypersil BDS C8 5 μm columns (Anachem, Luton, Beds.) using a mobile phase consisting of 0.05M potassium dihydrogen orthophosphate buffer containing 1 g/L of heptane sulphonic acid (sodium salt) and adjusted to pH 3.0 with concentrated orthophosphoric acid (89% by volume) and acetonitrile (11% by volume). The flow rate was 2 mL/minute, the detector wavelength was 283 nm, the injection volume was 20 μL and column temperature was 40° C. Samples were quantified with respect to an accurately prepared external standard (nominally 0.01 mg(base)/mL. Impurity Method: Chromatographic conditions were as for the assay except a detector wavelength of 210 nm was used. A second HPLC system was used with an aqueous to acetonitrile mobile phase ratio of 85% to 15% by volume, primarily to estimate specific process impurities. Impurities were quantified with respect to an accurately prepared external standard (nominally 0.005 mg(base)/mL).
TLC Method
20 μL of each sample was spotted onto a silica gel TLC plate (Merck 60F 254 ). The plate was developed to a height of 10 cm in an acetone/ammonium hydroxide (SG 0.88)/water (90:5:5% by volume) mobile phase. Impurities were estimated against dilute mitoguazone dihydrochloride spots, both under short wavelength ultraviolet light (254 nm), and following treatment with a nitroprusside (sodium)-ferricyanide spray reagent.
Results
Triplicate samples representing 0, 80%, 100% and 120% of the nominal mitoguazone dihydrochloride concentration were analyzed. The results obtained are given in Table I
TABLE I______________________________________Recovery Data HPLC DATA*Sample Identity % nominal added % nominal recovered______________________________________Blank 1 0 0Blank 2 0 0Blank 3 0 080% 1 81.1 81.080% 2 80.9 80.480% 3 83.6 83.3100% 1 101.5 101.6100% 2 103.6 103.5100% 3 104.6 104.2120% 1 122.3 121.3120% 2 121.9 122.5120% 3 119.0 118.8______________________________________ HPLC Assays*. Least Squares Regression Analysis of the data gave an average accuracy of 99.8% (Coefficient of Correlation 0.99935).
Analysis of Stressed Samples
Stressed samples were assayed by HPLC whilst chromatographic impurity levels were determined by HPLC and TLC. The chromatographic data are summarized in Table II.
TABLE II______________________________________Chromatographic Assay and Impurity Data for Stressed MitoguazoneDihydrochloride Impurities by Impurities by HPLC Assays HPLC TLCStress Condition (% w/w) (% w/w) (% w/w)______________________________________Control 100.6, 99.9 1.3 <0.7Heat 100.1, 100.2 1.1 <1.1Acidic 87.6, 87.0 14.0 <12.5Basic 74.9, 75.4 27.9 <25.3Aqueous 69.4, 69.1 31.9 <29.5Oxidative 93.7, 94.5 6.5 <5.8Light 99.9, 99.2 1.4 <0.7______________________________________
Using HPLC, TLC and mass spectroscopy, impurities contained in the starting materials or formed during the process of making the final product were identified and quantified.
We have found that the diaminoguanidine related impurities account for more than 70% of the total MGBG-dihydrochloride impurity level.
The general reaction scheme for the production of the impurities and their chemical names follows. ##STR2## wherein D= 2- (Aminoiminomethyl)hydrazono!propylidene!-carbonimidic dihydrazide.
E= 2- (Aminoiminomethhyl)hydrazono!-1-methylethylidene!-carbonimidic dihydrazide.
F=Bis 2- (Aminoiminomethyl)hydrazono!-1-methylethylidene!-carbonimidic dihydrazide.
G=Bis 2- (Aminoiminomethyl)hydrazono!propylidene!-carbonimidic dihydrazide.
H= 2- (Aminoiminomethyl)hydrazono!-1-methylethylidene! 2- (aminoiminomethyl)hydrazono! propylidene!-carbonimidic dihydrazide.
In copending application D.N. 70493, Ser. No. 08/655,512 now 5657883 filed of even date with the present application, reaction parameters were studied and modified in order to reduce impurities in the final product. Said copending application which is incorporated by reference in its entirety, discloses a process for the preparation of 2,2-'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximidamide! comprising the steps of:
a) removing impurities from aminoguanidine bicarbonate by suspending aminoguanidine bicarbonate in water and filtering the suspension;
b) reacting the filtered aminoguanidine bicarbonate with methylglyoxal dimethyl acetal in an aqueous reaction medium to produce 2,2'-(methyl-1,2-ethanediylidene)bis hydrazine carboximidamide!; and
c) purifying the 2,2'-(1-methy-1,2-ethanediylidene)bis hydrazine carboximidamide! by recrystallization from an acidic aqueous-isopropanol medium.
An essential step in the process is the removal of the impurities from the aminoguanidine bicarbonate starting material by suspending aminoguanidine bicarbonate in water and filtering out the impurities from the suspension.
We have now discovered that instead of using aminoguanidine bicarbonate as a starting material, aminoguanidine hydrochloride may be used to react with methylgyoxal dimethyl acetat in an aqueous reaction medium to produce 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine caroximidamide!. The process which includes a subsequent purification step provides a final product which is at least 99.5% pure.
SUMMARY OF THE INVENTION
The process of obtaining highly purified 2,2'-(1-methyl-1,2 ehanediylidene)bis bydrazine carboximidamide! involves reacting aminoguanidine hydrochloride with methylglyoxal dimethyl acetal which comprises the steps of:
a) dissolving one part aminoguanidine hydrochloride in a mixture of about 0.5 to 3 parts, preferably in about 0.93 parts, of water and about 0 to 3 parts of a water miscible organic solvent, preferably about 0.75 parts of isopropyl alcohol;
b) adjusting the pH of the solution to about 0 to 5, preferably about 0 to 1 with concentrated hydrochloric acid;
c) adding to the solution about 0.25 to 1 parts of methylglyoxal aldehyde, preferably about 0.5 parts of methylglyoxal dimethyl acetal, at a temperature of about 0° to 50° C., preferably at 25° to 30° C.;
d) stirring the reaction mixture for about 1 to 48 hours, preferably for about 1 to 16 hrs at ambient temperature;
e) adding about 0.5 to 20 parts of a water miscible organic solvent, preferably about 5 parts of isopropyl alcohol, to the reaction mixture to produce the solid 2,2'-(1-methyl-1,2 ethanediylidene)bis hydrazine carboximidamide!;
f) collecting the solid crude 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximidamide! by filtration and washing the same with 1 to 10 parts of an organic solvent, preferably with 1 to 2 parts of isopropyl alcohol; and
g) optionally drying the crude final product before purification in a 45° C. vacuum oven.
The purification process of the crude 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximidamide! comprises the steps of:
h) dissolving the crude compound in about 0.5 to 4 parts of deionized water, preferably in about 2 parts of deionized water;
i) adding about 0.5 to 2 parts of a water miscible organic solvent, preferably about 1 part of isopropanol;
j) adjusting the pH of the solution to about 0 to 5, and preferably to 0 to 1 with concentrated hydrochloric acid;
k) stirring the solution for about 0.5 to 2 hours while adding 0.1 to 2 parts of deionized water and maintaining the temperature of the solution at about 28°-32° C.;
l) filtering the solution to remove insoluble impurities;
m) adding to the filtered solution about 0.5 to 10 parts of a water miscible organic solvent, preferably about 5 parts of isopropyl alcohol to precipitate the compound;
n) cooling the mixture to about 0° to 25° C., preferably to about 10° C.;
o) collecting the solid product by filtration and washing the filtrate with 0.5 to 10 parts of an organic solvent, preferably with one part of isopropyl alcohol; and
p) drying the purified product.
DETAILED DESCRIPTION OF THE INVENTION
As used herein the process of synthesizing and purifying 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximide! also relates to and includes synthesis and purification of its various forms including its hydrochloride monohydrate, dihydrate and hemihydrate forms.
In the process of synthesizing and purifying 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximidamide! we prefer to use isopropyl alcohol. However, other water miscible organic solvents which may be used include methanol, ethenol, n-propyl alcohol, tetrahydrofuran, acetic acid, dimethyl formamide, acetonitrile and dimethyl sulfoxide or mixtures thereof.
Arninoguanidine hydrochloride, methylglyoxal aldehyde and methylglyoxal dimethyl acetal are available commercially, such as from Aldrich Chemical Co., and they can also be made by processes known in the art.
A representative example (Example 1) of synthesizing and purifying 2,2'-(1-methyl-1,2-ethanediylidine)bis hydrazine carboximidamide! illustrate the invention.
EXAMPLE 1
(A) Synthesis
60.0 grams of aminoguanidine hydrochloride was dissolved in 56 milliliters of deionized water and 36 grams of isopropyl alcohol. The pH of the solution was adjusted to about 0 to 1 by adding concentrated hydrochloric acid. 30.96 grams of methylglyoxal dimethylacetal was added over 1.5 to 3 hours while maintaining the reaction temperature between 25° and 30° C. The reaction mixture was then stirred at ambient temperature for an additional 16 hours. 240 grams of isopropyl alcohol was added and the reaction mixture was cooled to 10° C. The crude product which formed during the reaction process was collected by filtration and was washed with 90 milliliters of isopropyl alcohol. The washed filtrate was then dried in a 45° C. oven over night. The yield was 87% of the theoretical yield.
(B) Purification 79.3 grams of the crude product obtained in (A) was dissolved in 159 grams of deionized water at 35° C. 60.7 grams of isopropyl alcohol was added to the solution and the pH was adjusted to 0-1 by adding concentrated hydrochloric acid. The pH adjusted solution was stirred for 1 hour while maintaining its temperature at 28°-32° C. and adding 10 milliliters of deionized water. The mixture was filtered to remove impurities, such as mechanical dirt particles. 312 grams of isopropyl alcohol was then added to the solution to precipitate the product. The mixture containing the precipitated product was cooled to between 8°-12° C. and stirred for abut 15 minutes. The purified product was then washed with 68 milliliters of isopropyl alcohol and dried in a 45° C. vacuum oven.
The yield of the purified product was 67.5% of the theoretical yield.
Samples of purified 2,2'-(1-methyl-1,2-ethanediylidine)bis hydrazine carboximidamide! produced by: 1.) reacting aminoguanidine bicarbonate with methylglyoxal dimethyl acetal or 2.) reacting aminoguanidine hydrochloride with dimethylglyoxal dimethyl acetal were analyzed by HPLC. Comparative results are shown in Table II and Table III.
TABLE II______________________________________Assay Results For Lots of Aminoguanidine Bicarbonate Used inProduction of MGBG and Assay Results of MGBG Produced Therewith.MGBG Lots Produced Impurities (1,3-diamino- MGBG ETIFrom Aminoguanidine guanidine) by HPLC by HPLCBicarbonate % w/w Area %______________________________________L-1 1.0 1.73L-2 0.54 0.77L-3 0.38 0.65L-4 0.2 0.60L-5 0.2 0.64L-6 0.2 0.44______________________________________
TABLE III______________________________________Assay Results For Lots of Aminoguanidine Hydrochloride Used inProduction of MGBG and Assay Results of MGBG Produced TherewithMGBG Lots Produced Impurities (1,3-diamino- MGBG ETIFrom Aminoguanidine guanidine) by HPLC by HPLCHydrochloride % w/w Area %______________________________________L-7 none detected 0.07L-8 none detected 0.04______________________________________
Aminoguanidine hydrochloride was found to contain lower levels of impurities than aminoguanidine bicarbonate and gave a superior quality MGBG. Purity of MGBG produced by the use of aminoguanidine hydrochloride and according to the present invention was found to be as high as 99.9%. Such highly pure MGBG is well-suited for pharmaceutical compositions for the treatment of cancer and other diseases.
The invention has been described in detail with particular reference to certain 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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Process for the preparation of 2,2'-(1-methyl 1,2-ethanediylidene)bis hydrazine carboximidamide! by:
a) reacting aminoguanidine hydrochloride with methylglyoxal aldehyde or methylglyoxal dimethyl acetal; and
b) purifying the 2,2'-(1-methyl-1,2-ethanediylidene)bis hydrazine carboximidamide! by crystallization from an acidic aqueous-isopropyl alcohol medium.
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FIELD AND BACKGROUND OF THE INVENTION
This invention relates to a method of electroosmotically dehydrating sludge produced in processing service water, sewage or various types of industrial sewage. More particularly, the invention relates to such a method using a filter press.
The particles of sludge contained in service water sludge and sewage sludge, for example, are electrically negatively charged, while the water contained in the sludge is positively charged. In the dehydration method known as electroosmotic dehydration, the water contained in sludge moves electroosmotically toward a cathode, and the salt contained in the sludge is electrolyzed, so that the filtrate is acid on the anode side and alkaline on the cathode side.
Generally, metal ions precipitate as insoluble metal hydroxide on the alkaline side, and the precipitate sticks to the electrode surfaces and filter cloths on the cathode side and disadvantageously affects the electroosmotic dehydration. This can be prevented by a method of reversing the polarity of the electrodes for a few minutes at the last step, or for every several batches, of electroosmotic dehydration, in order for the acid filtrate to dissolve and remove the precipitate.
U.S. Pat. No. 5,092,974 dated Mar. 3, 1992 to Kondo et al. describes a process for compressive (pressurized) and electroosmotic dehydration using carbonaceous electrodes which contain carbon fibers, and the polarity of which is reversed during the dehydration process.
However, depending on the type of sludge, the reversal of polarity may not recover the blinded or clogged filter cloths. In particular, sludge containing a large amount of calcium blinds the filter cloths in a short time, so that the dehydration and the sludge cake release from the cloths may deteriorate.
When the liquid pH is 13 or higher near the cathode, Ca ++ ions having moved together with the liquid to the cathode side, and OH - ions produced on the cathode surfaces, are bound together to precipitate as insoluble calcium hydroxide [Ca(OH) 2 ] in the filter cloth fibers. This disadvantageously affects the filtering speed and the cake release.
SUMMARY OF THE INVENTION
This invention is characterized by electroosmotic dehydration with aluminum salt added to sludge to reduce the clogging of the filter cloths of the dehydrator, and to improve the cake release. The aluminum salt is preferably polyaluminum chloride.
Because aluminum has a less tendency to be ionized than calcium, the addition of aluminum salt to sludge to be dehydrated gives priority to Al 3+ ions being bound to OH - ions to precipitate aluminum hydroxide [Al(OH) 3 ], while calcium is discharged as still being Ca 2+ ions together with the filtrate, so that a reduced amount of calcium hydroxide [Ca(OH) 2 ] is produced.
The aluminum hydroxide is dissolved again when the filtrate pH is 10 or higher and discharged with the filtrate, thus reducing the precipitate on the cathode side and preventing the clogging of filter cloths on this side.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention is described below with reference to the accompanying drawings, wherein:
FIGS. 1a, 1b and 1c are schematic partial views in cross section of a pressurized electroosmotic dehydrator, showing steps of prior art sludge dehydration;
FIG. 2 is a flow diagram of a sludge dehydration process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 2, sludge 9 to be dehydrated is fed into a sludge tank 10 and stirred in it by a rotatable paddle or propeller 11. Similar stirrers are provided in other tanks of the system.
Perlite is mixed by a paddle 13 with water in a separate perlite tank 12. Perlite is added to the sludge to facilitate the dehydration of the sludge and the release of the resultant cake from the filter cloths of a pressurized electroosmotic dehydrator, as will be explained later.
Polyalkylmetacrylate as polymer is mixed with water in a polymer tank 14. Polymer is added to the sludge to coagulate the sludge into flocks to facilitate the succeeding screening of the sludge.
The sludge, the dilute perlite and the polymer are pumped by pumps to a common line 17 and to a coagulating and mixing tank 16, where they are mixed together and the sludge is coagulated. the coagulated sludge is fed through a conduit 16a to a predehydrator 18, where it is screened in order to concentrate it.
Polyaluminum chloride as aluminum salt is stirred in a "PAC" tank 20. The aluminum salt is pumped to a mixer 22 along with the screened sludge from the predehydrator screen 18, and in which the sludge and aluminum salt are mixed together by a paddle 23. The mixed sludge is fed to a concentrated sludge tank 24, from which it is pumped through a line 25 to a pressurized electroosmotic dehydrator 26.
The dehydrator 26 has a construction substantially as described in U.S. Pat. No. 5,034,111 dated Jul. 23, 1991 to Kondo et al. and illustrated in FIGS. 1a, 1b and 1c herein. The dehydrator 26 is connected to a DC power source 28. The sludge cake is discharged from the dehydrator 26 onto a conveyor 30, which conveys it to a cake container 32.
The dehydrator 26 processes the sludge substantially in the same manner as by the conventional process shown in FIGS. 1a-1c. With reference to FIG. 1a, the sludge C is forced through the feed bores 6 into the closed space formed between the press plates 2a and 2b and surrounded by the two filter cloths 3, and it is dehydrated by the squeezing pressure. The filtrate is discharged from the machine through the discharge bores 7.
With reference to FIG. 1b, compressed air is supplied to expand the diaphragm 4 on the press plate 2a toward the opposite plate 2b to create pressurized dehydration. Then, DC voltage is applied between the porous electrode plates 5a and 5b on the diaphragm 4 and press plate 2b, respectively, to make electroosmotic dehydration.
With reference to FIG. 1c, after the electroosmotic dehydration, the press plates 2a and 2b are opened, and the filter cloths 3 are lowered to discharge the sludge cake C.
Comparative tests have been carried out using the system of FIG. 2 for a mixture of the same weight of raw sludge and excess activated sludge, which were produced in a sewage plant. The dehydrator 26 had a filtering area of 2.1 m 2 .
The mixed sludge initially had a concentration of 3.42 wt. % and 34,200 mg/l of suspended solids.
The mixed sludge was mixed with perlite having a concentration of 5 wt. % in an amount of 15.37 wt. % of the total solids of the sludge, and with polyalkylmetacrylate having a concentration of 0.2 wt. % in an amount of 0.52 wt. % of the total sludge solids.
The pressure for squeezing the sludge into the dehydrator 26 was 4 kg/cm 2 . The pressure by each pressurized diaphragm of this dehydrator was 4 kg/cm 2 .
The DC voltage between the electrodes was 40 V. Initially, the electrode plate on each diaphragm was the anode.
The other conditions and results were as follows:
Example 1
13.75 liters of the mixed sludge mixed with the perlite and polymer were squeezed into the closed space between each pair of the press plates of the dehydrator for 15 minutes.
In 5 minutes after the compression started, the voltage was applied for 66 minutes until the sludge cake had a concentration of 35 wt. % (water content of 65 wt. %).
The voltage application was continued with the polarity reversed for 2 minutes.
The filtering speed was 1.23 kgDS/m 2 h (DS: dry solids). The consumed electric energy was 0.88 kWh/kgDS.
Example 2
The mixed sludge mixed with the perlite and polymer was further mixed with polyaluminum chloride having a concentration of 10 wt. % in an amount of 1.11 wt. % of the total sludge solids.
13.75 liters of the resultant sludge were squeezed into the closed space of the dehydrator for 15 minutes.
In 5 minutes after the compression started, the voltage was applied for 27 minutes until the cake had the concentration of 35 wt. %. This period is much shorter than in Example 1. The voltage application was continued with the polarity reversed for 2 minutes.
The filtering speed was 2.34 kgDS/m 2 h, which is much higher than in Example 1. The consumed electric energy was 0.43 kWh/kgDS, which is much lower than in Example 1. The cake release was much better than in Example 1.
For a mixture of the same weight of raw sludge and excess activated sludge, the amount of added polyaluminum chloride should be 0.7-1.5 wt. %. For raw sludge only, this amount should be 0.3-1.0 wt. %. For excess activated sludge only, this amount should be 1.0-2.0 wt. %.
It should be noted that aluminum sulfate, although it is aluminum salt, is not desirable if the electrodes are carbonaceous, because it causes corrosion. Also, any metal salt (such as iron salt) other than aluminum salt is not effective because the hydroxide is not dissolved again on the alkaline side.
As stated above, according to the present invention, the addition of aluminum salt to sludge reduces considerably the blinding or clogging of the filter cloths, improves the filtration, saves the amount of consumed electric power and improves the cake release. This stabilizes the dehydration for a long time, in combination with the polarity reversal of the electrode plates to dissolve and remove precipitate on the electrode surfaces.
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This disclosure relates to a process and apparatus for electroosmotic dehydration of sludge with aluminum salt added to the sludge to reduce the clogging of the filter cloths of the dehydrator, and to improve the cake release. The aluminum salt is preferably polyaluminum chloride.
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FIELD OF THE INVENTION
The present invention relates generally to banner support assemblies and, more particularly, to a banner support bracket for holding a banner taut via a banner rod.
BACKGROUND OF THE INVENTION
Banners are used by many organizations and municipalities to advertise various events or as general decorations throughout the year and during festivals or the like. The banners are generally supported from light poles, standards, or other similar structures by brackets with integral rods wherein the banner may be easily seen but still be out of reach of the public.
Because of the nature of banners, as opposed to flags, it is necessary to hold both longitudinal ends of the banner such that the banner is kept taut. Usually, each end of the banner includes a pocket or similar elongated opening therein into which is received a support rod. The pocket and rod generally extend the entire length of the banner at the particular longitudinal end of the banner.
Heretofore, various brackets have been developed for holding banners taut. Of these, some brackets have been developed to specifically address and withstand the various wind loads that banners are subjected to due to the fact that they are held taut like a sail and cannot flap and wave to release the wind energy, in contrast to a flag. Other banner brackets have been designed to maintain the banner taut by incorporating a fixed angle into a fixed rod holder.
However, the prior art banner brackets are only capable of supporting banners that are essentially rectangular in shape. The banners therefore have longitudinal ends that are essentially perpendicular to the post onto which the bracket is mounted. Thus, such prior art banner brackets will support only one banner configuration, i.e. the rectangular banner, whereas there are many other possible and more appealing configurations.
Furthermore, such prior art banner brackets that are vertically adjustable are cumbersome to vertically adjust in situations where there is a change in the longitudinal length of the banner, either through stretching of the banner during use or actual change thereof.
In view of the shortcomings of the prior art, it is thus an object of the present invention to provide a banner support bracket that is capable of supporting a variety of banner configurations.
It is further an object of the present invention to provide a banner support bracket that is easily vertically adjustable due to stretching of the banner during use, or in situations where the longitudinal dimension of the banner has changed.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a banner support bracket for holding any size of a banner mounting rod having a rod holder assembly that is easily longitudinally or vertically adjustable as well as incrementally angularly adjustable through a 180° angle defined from the vertical axis of movement of the rod holder assembly.
The present bracket is for supporting an end of a banner having a banner support rod. The banner bracket comprises, a base plate, a first wall disposed on an upper surface of the base plate and positioned essentially perpendicular thereto, the first wall having an elongated slot therethrough. A second wall is disposed on an upper surface of the base plate and positioned essentially perpendicular thereto, the second wall is in spaced relationship to the first wall thereby defining a channel therebetween, the second wall having an elongated slot therethrough, The bracket further provides a rod holder assembly disposed within the channel and adapted to removably retain a banner rod for supporting an end of a banner, the rod holder assembly including a bore therethrough. The rod holder assembly is selectively adjustably movable along the channel to vertically set the height thereof, and selectively securable against vertical movement by a bolt and nut extending through the first wall elongated channel, the rod holder bore, and the second wall elongated channel. The rod holder assembly is selectively angularly adjustable about a 180° arc of movement defined from an axis coaxial with the vertical plane of movement of the rod holder assembly.
Further, the present invention provides a bracket assembly for holding a first and second banner support rod to support and maintain a banner taut, one support rod is for retaining one end of the banner with the second support rod is for retaining the other end of the banner. The bracket assembly comprises a first and second bracket each having an elongated plate-like portion with the following common components. A first wall is disposed on an upper surface of the plate-like portion and positioned essentially perpendicular thereto, the first wall has an elongated recess on an inner surface thereof and an elongated slot therethrough. A second wall is disposed on an upper surface of the plate-like portion and positioned essentially perpendicular thereto, the second wall is in spaced relationship to the first wall and includes an elongated recess on an inner surface thereof thereby defining a slotted channel between the first and second wall, the second wall having an elongated slot therethrough. A rod holder assembly is further disposed within and retained by the channel and adapted to removably hold a banner rod for supporting an end of a banner. The rod holder assembly includes a bore therethrough, and is selectively adjustably movable along the channel to vertically set the height thereof, and selectively securable against vertical movement by a bolt and nut extending through the first wall elongated channel, the rod holder bore, and the second wall elongated channel. The rod holder assembly is selectively angularly adjustable about a 180° arc of movement defined from an axis coaxial with the vertical plane of movement of the rod holder assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above-recited features, advantages, and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
It is noted, however, that the appended drawings illustrate only typical embodiments of this invention and is therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. Reference the appended drawings, wherein:
FIG. 1 is a perspective view of the present banner bracket with a banner support rod therein;
FIG. 2 is a side elevational view of the present banner bracket of FIG. 1;
FIG. 3 is an exploded view of the present banner bracket;
FIG. 4 is a side view of the present banner bracket with a banner support rod therein depicting several of the various rod orientations achievable in accordance with the present invention;
FIGS. 5a-h are diagrammatic representations of various banner configurations supportable by a pair of banner brackets in accordance with the present invention;
FIG. 6 is a top plan view of the present banner bracket; and
FIG. 7 is an elevational view of a pair of banner brackets attached to a standard supporting the banner of FIG. 5c.
DETAILED DESCRIPTION
Referring now to FIGS. 1 and 2, there is shown a banner bracket generally designated 10 depicted supporting a banner support rod 12 in accordance with the present invention. Banner bracket 10 includes a plate-like member or base 14 defining an upper surface 13 and a lower surface 15. Lower surface 15 has a concave portion 16 that extends along the entire longitudinal length of base 14. Concave portion 16 defines a rate of curvature or arc from one edge 17 of base 14 to the other edge 19 of base 14 in order to conform to and facilitate the mounting thereof onto a street light pole, standard, or the like.
Disposed on one short end of base 14 and extending the entire length thereof is an elongated flange 18 that is essentially perpendicular to base 14. Disposed on the other short end of base 14 diametrically opposite flange 18 are two flanges 20, 21 that each extend essentially one-third of the length of the side. Flange 18 provides a positive stop at one end of base 14 for locating a strap or band when mounting banner bracket 10. Likewise, flanges 20, 21 provide a positive stop at one end of base 14 for locating a second strap or band when mounting banner bracket 10 onto a post. A first bore 22 and recess 23 are provided in base 14 on the end adjacent flanges 20, 21 through which is received a bolt 103 (see FIG. 7) for mounting banner bracket 10 onto a post. A second bore 24 is provided in base 14 on the end adjacent flange 18 through which is received a bolt 104 (see FIG. 7) for mounting banner bracket 10 onto a post.
Referring additionally to FIG. 6, integrally formed with base 14 are two upstanding walls 26, 28 spaced apart a given distance and defining a channel 29 in which a rod holder assembly 30 slides back and forth. When mounted on a post, rod holder assembly 30 slides vertically relative to the ground. Regardless of the mounting position of banner bracket, the term "vertical" as used herein is defined as the direction of back and forth travel of rod holder assembly 30 within channel 29. As can be seen in FIG. 6, walls 26, 28 are located a distance inwardly from each respective end 17, 19 and longitudinally extend about half the distance of base 14, disposed essentially in the middle thereof. Wall 26 includes an angle brace 110 for providing extra wind support, while wall 28 includes an angle brace 112 also for providing extra wind support. Wall 28 includes an elongated opening 58, while wall 26 includes a similar elongated opening 60. Each wall 26, 28 further includes a respective rectangular slot 60, 62 each defining a channel on the inside thereof such that slots 60, 62 are opposed and thus face each other. Rod holder assembly 30 is movably retained within slots 60, 62 such that rod holder assembly 30 may slide or adjust longitudinally along channel 29. Slots 60, 62 are open on one end to allow rod holder assembly 30 to be removed therefrom to change the angle of banner rod 12 as explained hereinbelow, but includes stops, of which only one stop 76 of wall 28 is shown, on the other end to prevent rod holder assembly 30 from exiting therefrom.
With reference to FIG. 3, there is shown an exploded view of the present banner bracket depicting the constituent parts of the rod holder assembly 30. Rod holder assembly 30 includes a swivel member 34 having a first cylindrical portion 36 with a cylindrical bore 38 in which is received the banner support rod 12. Banner support rod 12 thus slidingly fits into cylindrical rod bore 38 and is removably retained therein by a cotter pin 32. A bore 40 through first cylindrical portion 36 aligns with a bore 74 in banner rod 12 when banner rod 12 is properly inserted in cylindrical rod bore 38. Cotter pin 32 thus extends through bores 40 and 74 to retain banner support rod such that as rod holder assembly 30 moves, banner support rod 12 must move therewith.
Swivel member 34 further includes a second cylindrical portion 42 having a bolt bore 44 therethrough. Bolt bore 44 in second cylindrical portion 42 defines an axis that is essentially perpendicular to an axis defined by cylindrical rod bore 38. On one end of second cylindrical portion 42 is an annular set of teeth or ratchet 46. Rod holder assembly 30 also includes a sliding member 48 having a square back plate 50 and a nut shaped front 52. A bolt bore 54 extends therethrough and is coaxial with bolt bore 44. On the outside surface of nut shaped front 52 is a similar annular set of teeth or ratchet 56. Annular teeth 56 of sliding member 48 mate with annular teeth 46 of second cylindrical portion 42 when swivel member 34 and sliding member 48 are joined to form rod holder assembly 30. A bolt 68 transversely extends through elongated opening 60 of wall 26, through bolt bore 44 of second cylindrical portion 42, bolt bore 54 of sliding portion 48, and elongated opening 58 of wall 28. A washer 70 and nut 72 secures the threaded end of bolt 68. In this manner, rod holder assembly 30 is releasably secured along its travel path within channel 29. It should be noted that wall 26 includes on the outside surface an elongated groove 66 defining a plurality of bolt head recesses that define incremental steps along the travel path of rod holder assembly 30 into which rod holder assembly 30 may be secured.
FIG. 4 depicts several banner rod 12 orientations that are achievable in accordance with the present invention. Banner rod 12, shown in solid, is set at an angle of 90° relative to the vertical, or an axis defined by the longitudinal, or vertical, travel path of rod holder assembly 30 within channel 29. The phantom lines depict essentially 45° and 135° angles relative the vertical. The various angles are set by rotating swivel portion 34 relative sliding portion 48 and then placing rod holder assembly 30 into channel 29. At this point, rod holder assembly 30 is restrained from angle change since the width of channel 29 defined by walls 26, 28, is only slightly greater than the total width of second cylindrical portion 42 and sliding member 48 when adjoining. This then prevents angle change once being set and placed within channel 29. Bolt 68 along with washer 70 and nut 72 set the placement of rod holder assembly 30 along the travel path, as bolt head 69 of bolt 68 abuts the respective bolt recess of elongated groove 66.
Swivel portion 34 is rotatable in 15° increments relative to sliding portion 48 and the axis of the travel path of rod holder assembly 30 such that banner support rod 12 may be set at angles anywhere from 0° to 180° in the 15° increments. It should be appreciated that the size and spacing of the two sets of annular teeth 46, 56, defines the angle increments, and thus it would be known to one skilled in the art to change the degree increments by changing the teeth size and spacing for finer angle increments or greater angle increments.
Because of the nature of the annular teeth 46 and 56 of rod holder assembly 30, there is introduced a slight cantilever since although a 90° angle for banner support rod 12 would be achievable due to the 15° increments, the rod holder assembly 30 does not start out at exactly 0°. Thus, the 90° setting is either slightly less than 90° or more than 90°, depending on which longitudinal end of the banner is being supported. Likewise each angular setting would be slightly off of the "true" degree angle. This, however, helps maintain the banner taut.
Referring now to FIGS. 5a-h, there are depicted various configurations of banners supportable by a pair of spaced apart banner brackets as more fully described hereinbelow under the heading "Operation." Because rod holder assembly 30 is adjustably tiltable through an angle of 180° from the vertical, each banner bracket 10 can hold taut a banner having angled longitudinal ends as well as straight longitudinal ends, or a combination thereof. It should be here appreciated that two pairs of banner brackets 10 may be utilized to hold two banners with one pair of brackets holding one banner adjacent another banner held by the other pair of brackets. In this manner, various styles of display banners may be achieved.
FIG. 5a depicts a banner 90 having a top longitudinal end is cut perpendicular to the vertical or at an angle of 90°, with a bottom longitudinal end cut at an angle of approximately 135° degrees. Thus, in the case of the support of banner 90 depicted in FIG. 5a, the upper banner bracket rod holder would be set at 90°, while the lower banner bracket rod holder would be set at approximately 135°. It should be here appreciated that due to the orientation of the incremental ratchet of the rod holder as described hereinabove, a slight cantilever is introduced to maintain the banner taut. FIG. 5b depicts a banner 91 having a top longitudinal end that is cut at an angle of approximately 45° from the vertical axis, while the bottom longitudinal end is cut at an angle of approximately 135°. Thus, the pair of banner bracket rod holders would be set accordingly. FIG. 5c depicts another banner 92 having a top longitudinal end that is cut at an angle of approximately 45°, with a bottom longitudinal end cut at an angle of approximately 90°. In FIG. 5d, a banner 93 has a top longitudinal end cut at an angle of approximately 135°, while the bottom longitudinal end is also cut at an angle of approximately 135°. A further banner 94 is depicted in FIG. 5e having a top longitudinal end cut at an angle of approximately 135°, with a bottom longitudinal end cut at an angle of approximately 90°. FIG. 5f depicts a banner 95 having a top longitudinal end cut at approximately 135°, with a bottom end cut at an angle of approximately 45°. A yet further banner 96 is depicted in FIG. 5g. Banner 96 has a top longitudinal end cut at approximately 45°, with a bottom end cut at an angle of approximately 45°. Lastly, FIG. 5h depicts a banner 97 having a top longitudinal end cut at approximately 90°, with a bottom end cut at an angle of approximately 45°. It should be noted that these shapes are only illustrative of some of the many banner configurations that may be held by the present banner brackets, and is not intended to be an all inclusive, limiting, or exhaustive list.
In a preferred form, base 14 along with integral upstanding lateral walls 26, 28, and rod support assembly 30 are all cast from aluminum, here Almag 35 aluminum ingot, but other non-rusting metals and fabrication techniques may be utilized as is known to one skilled in the art. Furthermore, rod 12 is fabricated from fiberglass, but may be aluminum or other any other material which provides adequate support and relative flexibility in order to flex under winds loads as explained hereinabove. Dimensionally, rectangular base 14 is 31/2" by 71/2", while the rod holder assembly 30 enjoys a total travel path distance of 21/2". Rod 12 has an 11/16" diameter and a length of 321/2", with an engagement diameter of 15/16" for receipt into the rod holder assembly.
OPERATION
Referring now to FIG. 7, the manner in which the present banner brackets are mounted and adjusted for various banner configurations is presented. Generally, the banner brackets are mounted on a street lamp post or similar pole structure. In FIG. 7, a pair of identical banner brackets 10 are shown mounted to a post or standard 100 in spaced relationship according to the longitudinal size and cut of the banner to be supported. Brackets 10 are shown mounted to post 100 via bolts 103, 104 as well as strapped thereto via metal straps or bands 101, 102. It should be noted that it is generally not necessary to have both bolts and straps, as either one or the other may be used, however, for illustrative purposes both mounting methods are depicted, as some applications may indeed require or suggest the use of both methods. Flanges 19, 20, 21 help retain straps 101, 102 about upper surface 13 of base 14 such that straps 101, 102 do not slide off of the bracket.
Then, depending on the angle of cut of the ends of the banner, here banner 92 (FIG. 5c) is depicted, the angle of rods 12 are set by setting the corresponding angle of the respective rod holder. This is accomplished while rod holder assembly 30 is outside of channel 29 since even when bolt 68 is completely loosened or not in place at all, the angle of rod holder assembly 30 cannot be changed when disposed within channel 29.
Once the desired angle of each rod holder assembly 30 is set, the rod holder assembly is placed in the respective channel 29. The desired vertical placement of each rod holder assembly 30 is selected, which can be the same for both banner brackets 10 or may be different, depending on the placement of the banner brackets, and other factors such as stretching of the banner and the like. At this point, bolt 68 is inserted through wall 26, bores 44, 54, and wall 28. Nut 72 and washer 70 are placed on the threaded end of bolt 68 protruding from wall 28 and tightened. This sets the vertical distance.
Banner support rod 12 may already by in place within rod holder assembly 30 while adjustment is taking place, however, for ease of adjustment, it is preferable to insert banner support rod 12 after angular and vertical setting. One of the banner support rods 12 is inserted into the top pocket or sleeve 99 of banner 92, while the other of the banner support rods 12 is inserted into the bottom pocket or sleeve 98 of banner 92. Each banner support rod is placed in the respective rod holder assembly 12 and retained therein by the respective cotter pin 32. FIG. 6 shows a top view of the banner bracket 10 with the cotter pin 32 inserted therethrough.
Thus, once the desired angle for the banner is selected and set, any stretching of the banner or the like, may be easily countered by loosening nut 72 and sliding rod holder assembly 30 up, in the case of the upper banner bracket, and/or down, in the case of the lower banner bracket.
It can thus be appreciated that a change in length of the banner due to various factors can be easily accommodated for by vertical adjustment of a single bolt. Angular changes are likewise easily adjusted. Furthermore, a change in banners requires that only a cotter pin be removed to extricate the support rod from the rod holder, while a single bolt is loosened to change the length.
While the foregoing is directed to the preferred embodiment 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 which follow.
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A banner support bracket includes a plate-like member having a slightly concave rear surface to conform to a support post during mounting, and two spaced-apart upstanding walls defining a channel therebetween. A rod holder assembly is disposed within the channel and removably retains a banner rod through engagement with a cotter pin. The rod holder assembly is vertically movable along the length of the channel as well as variably tiltable through an angle of 180° from the vertical axis of movement. The ability of the rod holder assembly, and thus the support rod, to assume variable angles permits a wide variety of banner configurations to be supported. Two such banner bracket supports are mounted to a standard in order to hold the longitudinal ends of the banner taut regardless of the angle of cut of the banner ends. A slight cantilever built in to the rod holder assembly helps keep the banner taut.
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[0001] The application claims the benefit of U.S. Provisional Patent Application No. 60/485,077 filed Jul. 3, 2003.
TECHNICAL FIELD
[0002] This invention relates to optical fiber networks.
BACKGROUND
[0003] FIG. 1 shows optical power as a function of current for an optical transmitter over time. In general, digital optical communication systems transmit binary data using two levels of optical power, where the higher power level represents a binary 1 and the lower power level represents a binary 0. These two power levels can be represented as P 1 and P 0 , where P 1 >P 0 and the units of power are watts. The difference between P 1 and P 0 is an average power P avg .
[0004] In optical transmitters, electrical current is converted to optical power and in optical receivers optical power is converted back to electrical current. The electrical currents I 1 and I 0 are proportional to the corresponding optical power levels and are controlled by the limit on modulation (I mod ) and bias (I bias ) currents of the transmitter's laser diode.
[0005] The ratio between the high level and the low level shown in the equation below is defined as the “extinction ratio” and is represented by the symbol r e .
r e = I 1 I 0 = P 1 P 0
In an ideal transmitter, P 0 would be zero and thus r e would be infinite. In most practical optical transmitters, however, the laser must be biased so that P 0 is in the vicinity of the laser threshold, meaning that a finite amount of optical power is emitted at the low level and thus P 0 >0. This increase in transmitted power due to non-ideal values of extinction ratio is called the “power penalty”. As the extinction ratio is degraded below its ideal value of infinity, the average power transmitted must be increased in order to maintain a constant Bit Error Rate (BER).
[0007] Seemingly small changes in extinction ratio can make a relatively large difference in power required to maintain a constant BER. The effect is especially acute for extinction ratios less than seven, where a change of one in extinction ratio value translates to an approximate 10% change in required average power. This additional required power is aptly termed the “power penalty”, as nothing is gained by this increase in power other than the unnecessary privilege of operating at a reduced extinction ratio.
[0008] As illustrated in FIG. 1 , the slope of a laser diode's current to optical power transfer characteristics changes as a function of process, increasing temperature and age (e.g. curves T 1 and T 2 ). The slope variation can affect the extinction ratio, and therefore the BER, during the operational lifetime of an optical transmitter.
SUMMARY
[0009] In one aspect, a method of controlling extinction ratio in an optical network configured for transmitting and receiving network data is provided. The extinction ratio can be controlled by providing a first optical transceiver configured for sending modulated light, a second optical transceiver configured for receiving modulated light, taking a digital measurement of at least one signal parameter reflecting the optical power levels of the received modulated light, and adjusting the modulated light sent by the first optical transceiver in accordance with the digital measurement.
[0010] Aspects of the invention can include one or more of the following features.
[0011] The measured signal parameter can include the high and low power levels of the received modulated light. The measured signal parameter can be the difference between high and low power levels of the received modulated light. The measured signal parameter can be the average power level of the received modulated light.
[0012] The digital measurement can be stored in memory. The average power levels of the received modulated light can be computed using the measured high and low power levels. The difference between measured high and low power levels can also be computed.
[0013] Data of a measured signal parameter can be transmitted from the second optical transceiver to the first optical transceiver. Network data can also be transmitted from the second optical transceiver to the first optical transceiver and the data of the digital measurement can be multiplexed into the network data.
[0014] A predetermined extinction ratio can be transmitted from the second optical transceiver to the first optical transceiver, or otherwise provided to the first optical transceiver. The predetermined signal parameter can be extinction ratio. The predetermined signal parameter can be average optical power. The predetermined signal parameter can be compared with the measured signal parameter.
[0015] Adjusting the modulated light sent by the first optical transceiver can include adjusting its extinction ratio. The average optical power of the modulated light sent by the fist optical transceiver can also be adjusted. Adjusting the extinction ratio of the sent modulated optical power can include adjusting the modulation current supplied to a laser diode in the first optical transceiver. The bias supplied to the laser diode can also be adjusted to adjust the average optical power of the sent modulated light.
[0016] Predetermined threshold values of bias and/or modulation current can be provided. The predetermined values of bias and/or modulation current can be compared with the adjusted bias and modulation current to determine whether the threshold values have been exceeded. If the threshold values have been exceeded, a visual indication can be provided.
[0017] Trace histories of the bias current adjustments and/or modulation current adjustment can be stored. The end of life of the laser diode can be predicted on the basis of the stored trace histories of the bias current adjustments and/or modulation current adjustments.
[0018] A visual indication of the time to end of life can be provided.
[0019] In another aspect, an optical network for transmitting and receiving network data is disclosed. The optical network can include a first optical transceiver configured for sending modulated light, a second optical transceiver configured for receiving modulated light, an optical fiber coupling the first optical transceiver to the second optical transceiver. The second optical transceiver can be configured to perform a digital measurement of at least one signal parameter reflecting optical power levels of the received modulated light. The first optical transceiver can be configured to adjust the modulated light sent by the first optical transceiver in accordance with the digital measurement.
[0020] Aspects of the invention may include one or more of the following features.
[0021] The signal parameter can include the high and low power levels, the difference between the high and low power levels and/or the average power level of the received modulated light.
[0022] The network can include a memory configured to store the digital measurement and a communication logic configured to compute the average power level and/or the difference between the high and low power levels of the received modulated light using the measured high and low power levels.
[0023] The second optical transceiver can be configured to transmit data of the measured signal parameter to the first optical transceiver. The data of the measured signal parameter can be multiplexed into the network data.
[0024] The second optical transceiver can be configured to transmit a predetermined signal parameter to the first optical transceiver. The predetermined signal parameter can include a predetermined extinction ratio and/or a predetermined average optical power. The fist optical transceiver can be configured to compare a predetermined signal parameter to the measured signal parameter.
[0025] The first optical transceiver can be configured to receive a predetermined signal parameter and compare the predetermined signal parameter to the measured signal parameter. The predetermined signal parameter can include a predetermined extinction ratio and/or a predetermined received average optical power.
[0026] Adjusting the modulated light sent by the first optical transceiver can include adjusting an extinction ratio and/or an average transmitted optical power of the sent modulated light. The first optical transceiver can include a laser diode and adjusting the extinction ratio of the sent modulated light can include adjusting the range of the modulation current supplied to the laser diode. The first optical transceiver can include a laser diode and adjusting the average transmitted optical power of the sent modulated light can include adjusting the bias current supplied to the laser diode.
[0027] The network can include a memory configured to store a predetermined threshold value of a range of a modulation current. The network can include a communication logic configured to compare the predetermined threshold value of a range of a modulation current to the adjusted modulation current supplied to a laser diode. If the adjusted range of modulation current exceeds the threshold value, a visual indication can be provided.
[0028] The network can include a memory configured to store a predetermined threshold value of bias current. The network can include a communication logic configured to compare the predetermined threshold value of bias current to the adjusted bias supplied to a laser diode. If the adjusted bias current exceeds the threshold value, a visual indication can be provided.
[0029] The network can include a memory configured for storing trace histories of the modulation and/or bias current adjustments. The network can include communication logic configured to predict the end of life of a first optical transceiver's laser diode on the basis of the trace histories of the modulation and/or bias current adjustments.
[0030] The network can include communication logic configured to provide a visual indication reflecting a predicted time to end of life.
[0031] Advantages of the invention can include one or more of following. Aspects of the invention enable the control of extinction ratio in optical fiber networks without the use of ancillary detectors such as photodiodes dedicated exclusively for extinction ratio monitoring. This allows extinction ratio to be controlled with fewer components than conventional systems. Moreover, aspects of the invention accurately control extinction ratio by using optical transceivers capable of accurately detecting high and low power levels in the data signal. Further, aspects of the invention provide for an efficient way to maintain an optical network over time as components reach their end of life.
[0032] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
[0033] FIG. 1 shows optical power as a function of current for an optical transmitter over time.
[0034] FIG. 2 shows an optical fiber network.
[0035] FIG. 3 shows a block diagram of a passive optical fiber network.
[0036] FIG. 4 is a flow diagram showing a method of controlling extinction ratio in an optical network.
[0037] Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0038] FIG. 2 shows a high-level fiber optic data network 50 . The network includes a first transceiver 200 in communication with a second transceiver 201 via a fiber 208 . The first transceiver 200 and the second transceiver 201 include transmitter circuitry (Tx) 234 , 235 to convert electrical data input signals into modulated light signals for transmission over the fiber 208 . In addition, the first transceiver 200 and the second transceiver 201 also include receiver circuitry (Rx) 233 , 236 to convert optical signals received via the fiber 208 into electrical signals and to detect and recover encoded data and/or clock signals. First transceiver 200 and second transceiver 201 may contain a micro controller (not shown) and/or other communication logic and memory 231 , 232 for network protocol operation. Although the illustrated and described implementations of the transceivers 200 , 201 include communication logic and memory in a same package or device as the transmitter circuitry 234 , 235 and receiver circuitry 233 , 236 , other transceiver configurations may also be used.
[0039] First transceiver 200 transmits/receives data to/from the second transceiver 201 in the form of modulated optical light signals via the optical fiber 208 . The transmission mode of the data sent over the optical fiber 208 may be continuous, burst or both burst and continuous modes. Both transceivers 200 , 201 may transmit a same wavelength (e.g., the light signals are polarized and the polarization of light transmitted from one of the transceivers is perpendicular to the polarization of the light transmitted by the other transceiver). Alternatively, a single wavelength can be used by both transceivers 200 , 201 (e.g., the transmissions can be made in accordance with a time-division multiplexing scheme or similar protocol).
[0040] In another implementation, bi-directional wavelength-division multiplexing (WDM) may also be used. Bi-directional WDM is herein defined as any technique by which two optical signals having different wavelengths may be simultaneously transmitted bi-directionally with one wavelength used in each direction over a single fiber. In yet another implementation, bi-directional dense wavelength-division multiplexing (DWDM) may be used. Bi-directional DWDM is herein defined as any technique by which more than two optical signals having different wavelengths may be simultaneously transmitted bi-directionally with more than one wavelength used in each direction over a single fiber with each wavelength unique to a direction. For example, if wavelength division multiplexing is used, the first transceiver 200 may transmit data to the second transceiver 201 utilizing a first wavelength of modulated light conveyed via the fiber 208 and, similarly, the second transceiver 201 may transmit data via the same fiber 208 to the first transceiver 200 utilizing a second wavelength of modulated light conveyed via the same fiber 208 . Because only a single fiber is used, this type of transmission system is commonly referred to as a bi-directional transmission system. Although the fiber optic network illustrated in FIG. 2 includes a first transceiver 200 in communication with a second transceiver 201 via a single fiber 208 , other implementations of fiber optic networks, such as those having a first transceiver in communication with a plurality of transceivers via a plurality of fibers (not shown), may also be used.
[0041] Electrical data input signals (Data IN 1 ) 215 , as well as any optional clock signal (Data Clock IN 1 ) 216 , are routed to the transceiver 200 from an external data source (not shown) for processing by the communication logic and memory 231 . Communication logic and memory 231 process the data and clock signals in accordance with an in-use network protocol. Communication logic and memory 231 , 232 provides management functions for received and transmitted data including queue management (e.g., independent link control) for each respective link, demultiplexing/multiplexing and other functions as described further below. The processed signals are transmitted by the transmitter circuitry 234 . The resulting modulated light signals produced from the first transceiver's 200 transmitter 234 are then conveyed to the second transceiver 201 via the fiber 208 . The second transceiver 201 , in turn, receives the modulated light signals via the receiver circuitry 236 , converts the light signals to electrical signals, processes the electrical signals using the communication logic and memory 232 (in accordance with an in-use network protocol) and, optionally, outputs the electrical data output signals (Data Out 1 ) 219 , as well as any optional clock signals (Data Clock Out 1 ) 220 .
[0042] Similarly, the second transceiver 201 receives electrical data input signals (Data IN 1 ) 223 , as well as any optional clock signals (Data Clock IN) 224 , from an external data source (not shown) for processing by the communication logic and memory 232 and transmission by the transmitter circuitry 235 . The resulting modulated light signals produced from the second transceiver's 201 transmitter 235 are then conveyed to the first transceiver 200 using the optical fiber 208 . The first transceiver 200 , in turn, receives the modulated light signals via the receiver circuitry 233 , converts the light signals to electrical signals, processes the electrical signals using the communication logic and memory 231 (in accordance with an in-use network protocol), and, optionally, outputs the electrical data output signals (Data Out 1 ) 227 , as well as any optional clock signals (Data Clock Out 1 ) 228 .
[0043] Fiber optic data network 50 may also include a plurality of electrical input and clock input signals, denoted herein as Data IN N 217 / 225 and Data Clock IN N 218 / 226 , respectively, and a plurality of electrical output and clock output signals, denoted herein as Data Out N 229 / 221 and Data Clock Out N 230 / 222 , respectively. The information provided by the plurality of electrical input signals may or may not be used by a given transceiver to transmit information via the fiber 208 and, likewise, the information received via the fiber 208 by a given transceiver may or may not be outputted by the plurality of electrical output signals. The plurality of electrical signals denoted above can be combined to form data plane or control plane bus(es) for input and output signals respectively. In some implementations, the plurality of electrical data input signals and electrical data output signals are used by logic devices or other devices located outside (not shown) a given transceiver to communicate with the transceiver's communication logic and memory 231 , 132 , transmit circuitry 234 , 235 , and/or receive circuitry 233 , 236 .
[0044] FIG. 3 illustrates an implementation of a passive optical network (PON) 52 , where the functions described above associated with the first transceiver 200 and the second transceiver 201 of FIG. 2 , are implemented in an optical line terminator (OLT) 350 and one ore more optical networking units (ONU) 355 , and/or optical networking terminals (ONT) 360 , respectively. PON(s) 52 may be configured in either a point-to-point network architecture, wherein one OLT 350 is connected to one ONT 360 or ONU 355 , or a point-to-multipoint network architecture, wherein one OLT 350 is connected to a plurality of ONT(s) 360 and/or ONU(s) 355 . In the implementation shown in FIG. 3 , an OLT 350 is in communication with multiple ONTs/ONUs 360 , 355 via a plurality of optical fibers 352 . The fiber 352 coupling the OLT 350 to the PON 52 is also coupled to other fibers 352 connecting the ONTs/ONUs 360 , 355 by one or more passive optical splitters 157 . All of the optical elements between an OLT and ONTs/ONUs are often referred to as the Optical Distribution Network (ODN). Other alternate network configurations, including alternate implementations of point-to-point and point-to-multipoint networks are also possible.
[0045] A receiver RX 236 of a transceiver 201 receives optical data transmissions from another transceiver 200 in the form of modulated light. The receiver RX 236 is capable of digitally measuring the received optical power of the data transmissions. The digital measurements include the received optical power for the high and the low data transmission and/or the difference between the optical high and the optical low data transmissions. The Communication Logic & Memory 232 of transceiver 201 stores the digital measurement(s) for eventual transmission back to the transmitting transceiver 200 . Additionally the Communication Logic & Memory 232 may compute and store, an average of the stored high, low and/or difference values for eventual transmission back to the transmitting transceiver 200 . The Communication Logic & Memory 232 may also compute and store the difference between a desired value and the stored values for eventual transmission back to the transmitting transceiver 200 . The Communication Logic & Memory 232 can include volatile and/or non-volatile memory, registers, buffers, or other circuitry for storing data. The transmission of the digital measurement(s) is accomplished by multiplexing a message containing the digital measurement(s) into the user data, management and/or control traffic of the network protocol in-use.
[0046] Various events can trigger the transceiver 201 to begin measuring and/or storing data about the extinction ratio and average received power of the received modulated light. For example, the transceiver 201 can perform the measurements automatically at predetermined intervals. The transceiver 201 can also receive a message to measure extinction ratio and/or average power from some other transceiver in the fiber optical network. This message can come from the transmitting transceiver 200 , or from some upstream transceiver, for example, a transceiver that can transmit to transceiver 201 .
[0047] Transmitting transceiver 200 may have prior knowledge of receiving transceiver's 201 desired received extinction ratio and desired received average optical power. Alternatively, receiving transceiver 201 may transmit its desired received extinction ratio and desired received average optical power with the digital measurement(s). Once transmitting transceiver 200 receives the digital measurement(s) and/or the any of the stored values described above, the extinction ratio and average transmitting optical power of transmitter Tx 234 may be adjusted. The adjustment of the average transmitting power is accomplished by changing the I bias current to the laser diode contain in transmitter Tx 234 appropriately to match receive transceiver's 201 desired received optical power based on the digital measurement(s). The adjustment of the extinction ratio is accomplished by changing the range of the I mod current to the laser diode contain in transmitter Tx 234 appropriately to match the receive transceiver's 201 desired received extinction ratio based on the digital measurement(s).
[0048] FIG. 4 is a flow chart diagram showing a method of controlling extinction ratio. First a receiving transceiver measures the optical power highs and lows of a received data signal 410 . Next, the average received optical power, the difference between the high and low power level, and the extinction ratio are calculated 420 . This information or a subset thereof is then transmitted through the network to the transmitting transceiver 430 . The measured values and/or calculated values are then compared with predetermined values for extinction ratio and average transmitted power 440 . The bias and modulation current of the laser diode in the transceiver's transmitter are then adjusted such that the average power and extinction ratio of the data signal received at the receiving transceiver match the predetermined values 450 .
[0049] With a trace history of changes to a transceiver's extinction ratio and/or average transmitted power (e.g. I bias and I mod current changes) or with knowledge of present I bias current value and range of I mod current, a prediction can be made of a period of time before “end of life” of the transceiver's laser diode. The trace history may be stored at the transceiver, for example in the communication logic and memory, or at a network entity operating at an application layer in the protocol in-use according to the Open Systems Interconnection (OSI) 7 layer reference model (hereby included by reference). Alternatively, the transceiver may also have a predetermined thresholds for I bias and I mod currents to predict the “end of life” of its laser diode. Once the I bias and I mod currents pass or cross the thresholds the transceiver may give a visual indication of having reached the predetermined prediction period or period before “end of life”. In either cases, the transceiver may declare by means of a visual indication of having reached the period before “end of life” e.g., light an LED, change an LED's color or generate a message to a network entity operating at an OSI application layer via the protocol in-use resulting in a visible report. The comparing and declaration functions can be implemented in the communication logic.
[0050] Once a transceiver is not able to adjust its extinction ratio to meet a desired extinction ratio then the laser diode within the transceiver is declared to have reached its “end of life”. Alternatively declaring “end of life” may be triggered by detecting I bias and I mod currents passing or crossing a predetermined threshold wherein the laser diode consumers too much power to maintain a desired extinction ratio or average transmitted power. In either case, the transceiver may declare by means of a visual indication of having reached “end of life” e.g., light an LED, change an LED's color or generate a message to a network entity operating at an OSI application layer via the protocol in-use resulting in a visible report.
[0051] Although the invention has been described in terms of particular implementations, one of ordinary skill in the art, in light of this teaching, can generate additional implementations and modifications without departing from the spirit of or exceeding the scope of the claimed invention. Accordingly, it is to be understood that the drawings and descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof. Accordingly, other embodiments are within the scope of the following claims.
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A method and system for controlling extinction ratio in an optical network is disclosed. A first optical transceiver sends modulated light to a second optical transceiver and a digital measurement of a signal parameter reflecting the optical power levels of the received modulated light is taken. The modulated light sent by the first optical transceiver is adjusted in accordance with the digital measurement.
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The invention was made under a U.S. Government contract and the Government has rights herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a ceramic seal capable of enduring high temperature environments and dynamic conditions. The invention is particularly directed to sealing gaps between moveable engine panels and adjacent engine sidewalls.
2. Description of the Prior Art
Many ceramic fiber sealing rings or gaskets are known in the prior art. Conventionally, these sealing materials comprise resilient ceramic fibers in the form of a fiber tow, randomly oriented, or in the form of a braided rope. Such ceramic seals are limited in their application by such factors as the operating temperature of the environment, frictional wear, vibrational factors, strength, and brittleness.
U.S. Pat. No. 5,014,917 to Sirocky et al describes a flexible thermal barrier seal for use at temperatures up to about 1370° C. The seal disclosed comprises a high temperature outer sheathing such as a braided ceramic fiber, surrounding a core of densely packed high temperature particles, e.g. particulate ceramic. The seal is highly flexible due to the particulate core, but highly temperature resistant due to the specific materials employed.
SUMMARY OF THE INVENTION
The present invention comprises a sealing material in the form of a hollow, circular cross-section tube or pipe of ceramic fiber material. The seal of this invention, moreover, is designed so as to expand and contract, and to move in compliance with the dynamic environment in which it is located with sufficient flexibility to seal against significantly distorted panels. Further, the seal is designed so as to carry a cooling medium, such as gaseous helium or hydrogen, in its interior, which coolant may be permitted to pass through the ceramic walls of the tubular seal so as to provide cooling to the surfaces in contact therewith. The seal comprises multiple layers of two or three dimensionally braided or woven flexible ceramic fibers, in the form of a tube or pipe, the inner surface of which is impregnated with a porous elastomer such as silicone.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A need exists for compliant, low leakage, dynamic seals capable of withstanding very high temperature environments, particularly those wherein a sliding engagement is present. In the past, moderately high temperature requirements have been met through the use of such materials as asbestos or ceramic fiber. Such materials, however, are unable to meet some of the requirements of modem high temperature engines, particularly in combustion areas. The present invention overcomes the problems of past attempts by incorporating transpiration cooling into the seal means, so as to provide a cooling effect in addition to the high temperature resistance of the ceramic fibers employed. While transpiration cooling may be achieved from one surface to the other of a flat, oval, dog-bone, circular, or otherwise formed solid seal or insulation barrier of ceramic fiber composition, the present invention is specifically directed to a seal means wherein gaseous coolant is passed from the interior to the exterior of a hollow body.
The basic seal of the present invention comprises a hollow, circular-cross section hose of braided or layered ceramic fiber. The primary features considered beneficial to the use of ceramic fibers are the availability of continuous filament fibers for simplified fabrication and for final product structural integrity, and chemical stability in the presence of combustion products. In addition, ceramic fibers provide the maximum working strength at minimum tow bundle size, in most instances. Still further, ceramic fibers permit the use of minimum fiber diameter (denier), enabling one to obtain tight tow bend radii, where required.
The preferred ceramic materials for this purpose comprise Nextel® alumina-based fibers, available from the 3M Company. Nextel® 440, for example, comprises 70% alumina, 28% silica, and 2% boric oxide. Nextel® 312, the most preferred ceramic fiber, comprises 62% alumina, 24% silica, and 14% boric oxide. Such materials offer high operating temperature, e.g. in excess of about 1200° C., as well as resistance to chemical attack by either hydrogen or oxygen, while having low densities.
Other ceramic fibers are also suitable for use in this invention, and the selection of the specific material for use is dependent upon a number of factors. First, it is noted that continuous fibers are advantageous, and that smaller denier tows are preferred, so as to provide a more flexible fiber tow. Next, since one purpose of this invention is to provide a high temperature seal, it is obviously advantageous to provide a ceramic fiber having high strength at elevated temperatures. Further, a high tensile strain capability will result in a stronger and more reliable seal. Alumina-based fibers containing up to about 15 weight percent boric oxide and less than about 30 percent by weight silica are preferred. High silica content fibers are generally less desirable. Other fibers which have been found acceptable include Nicalon®, available from Nippon-Dow, comprising 90% silicon carbide, 10% silica, and Tyranno®, a family of silicon carbide and silica fibers containing titanium, available from Ube Industries and Textron.
The wall thickness of the braided hose will, of course, be dependent upon the size of the seal required for any given purpose, but may vary from about 0.10 to about 0.30 inches.
Porosity of such braided tubing is generally high, to the extent that gaseous coolant will flow at a high rate through the walls of the tubing. For use in transpiration cooling, it is desirable to control that flow of coolant material, so as to minimize storage requirements for the coolant material.
In the present invention, the flow of coolant material through the sidewalls of the seal material may be controlled by impregnating the ceramic fibers, on the inside surface of the tube or pipe, with a silicone elastomer such as RTV 159, a vinyl methyl silicone with ferrous oxide filler, available from General Electric. Such elastomeric impregnants are preferably applied to the inside surface of the hollow seal, but may be applied to the outside surface as well. Silicone elastomers are the preferred impregnant for this purpose, due to their ability to withstand cryogenic temperatures such as encountered in contacting liquid/gaseous helium or hydrogen. Silicone elastomers have been found to be superior to fluorocarbons in this respect.
Gases such as hydrogen and helium are capable of flowing easily through silicone elastomers due to their porosity, but such elastomers do block a significant portion of the flow of hydrogen and helium which would normally pass through the ceramic fibers. Minimizing this flow of coolant is critical due to tankage requirements for the coolant material. Thus, a balance must be achieved between the cooling effect to be obtained and the amount of cooling material available. Factors in achieving this balance include the overall membrane thickness, the weave of the ceramic fibers, the denier of the fibers, the braid angle of the seal, the depth of elastomer penetration into the ceramic fiber matrix, and variations in composition of both the ceramic and the elastomeric materials. In addition, coolant temperature and pressure may be varied in use, as well as the choice of gas utilized. Thus, a multitude of variables are to be considered in the formulation of the seal of the present invention.
A number of Nextel® 312 fabric samples were tested for permeability to helium, both with a surface coating of silicone elastomer and without. The procedure (ASTM C20) for determining the physical properties of the fabric samples was first investigated for reproducibility by analyzing four samples cut from a piece of finely woven Nextel® fabric. Table I sets forth the results from the testing and the dry weight of the sample specimens.
TABLE I______________________________________Properties of samples from a finely woven Nextal ® 312 fabric. Sample Apparent BulkSample Dry Weight Specific Density ApparentNumber (g) Gravity (g/cc) Porosity______________________________________1 0.22 2.73 1.05 61.5%2 0.21 2.73 1.07 60.9%3 0.17 2.70 1.02 62.3%4 0.21 2.74 1.07 61.0%Average -- 2.73 ± 0.02 1.05 ± 0.02 61.4% ± 0.6______________________________________
A 5 inch by 36 inch piece of similarly woven Nextel® fabric was then coated with RTV 159 silicone elastomer, by spraying a 25 weight percent solution thereof in methyl ethyl ketone onto one surface of the fabric, using six spray passes across the fabric strip. The elastomer coated strip was cured by exposure to 90% humidity at 100° F. in a humidity chamber for four days. After completion of the curing, a 4 inch diameter circle test specimen was cut for the flow test rig. A similar specimen of uncoated fabric was also cut and tested to establish a baseline flow rate for the fabric itself. Small pieces of both coated and uncoated fabric were obtained and used to measure bulk density, apparent specific gravity, and apparent porosity. The values obtained for these measurements are given in Table II.
TABLE II__________________________________________________________________________Properties of samples from a finely woven Nextel ® 312 fabricbefore and after coating with RTV 159. Apparent BulkSampleCoated/ Sample Dry Specific Density ApparentNumberUncoated Weight (g) Gravity (g/cc) Porosity__________________________________________________________________________1 Uncoated 0.13 2.59 0.73 71.7%2 Uncoated 0.11 2.48 0.80 67.6%3 Uncoated -- 2.50 0.76 61.0%AverageUncoated 0.11 2.53 ± 0.06 0.77 ± 0.03 69.6% ± 2.91 Coated 0.35 1.82 1.03 43.0%2 Coated 0.40 1.86 1.07 42.6%3 Coated 0.32 1.84 0.94 48.9%4 Coated 0.30 1.89 1.00 47.1%5 Coated 0.23 1.82 1.02 43.9%AverageCoated -- 1.85 ± 0.03 1.01 ± 0.05 45.1% ± 2.8__________________________________________________________________________
Five inch squares were masked off at each end of the remaining coated fabric strip, and sprayed a second time with the RTV 159 solution. The second coat was applied in two passes, directly over the first coat on one sample, and on the opposite side of the fabric on the second sample. After curing as above, flow test specimens were cut from the 5 inch squares. Table Ill contains the values of the physical properties determined for these doubly coated specimens.
TABLE III______________________________________Properties of Nextel ® fabric with second coat of RTV 159. Sample Apparent BulkSample Dry Weight Specific Density ApparentNumber (g) Gravity (g/cc) Porosity______________________________________2nd Coat Applied Over 1st Coat:1 0.60 1.68 1.23 26.9%2 0.38 1.67 1.16 30.7%3 0.35 1.69 1.22 28.1%4 0.36 1.65 1.15 30.0%5 0.33 1.63 1.13 30.9%6 0.35 1.65 1.16 29.5%7 0.28 1.67 1.16 30.4%Average -- 1.66 ± 0.02 1.17 ± 0.04 29.5% ± 1.52nd Coat Applied Opposite 1st Coat:1 0.48 1.62 1.24 23.4%2 0.45 1.62 1.23 24.0%3 0.46 1.62 1.26 23.1%4 0.28 1.67 1.24 26.1%5 0.28 1.61 1.27 21.0%6 0.23 1.63 1.26 22.4%Average -- 1.63 ± 0.02 1.25 ± 0.02 23.2% ± 1.8______________________________________
A seal in accordance with the present invention is prepared by weaving/braiding a hollow tube of Nextel® 312 ceramic fiber, having an outside diameter of 1.0 inch and an inside diameter of 0.625 inch. The tube is then subjected to heat cleaning at about 1000° F. for about 12 hours to remove organic polymer sizing used as an aid in weaving. After cleaning, the material is subjected to heat treatment at a temperature of about 1688° F. for about 12 hours. The inside surface of this heat treated tube is then impregnated to a depth of about 0.075 inch with RTV 159 liquid silicone elastomer. The elastomeric coating is then cured at room temperature and 50% relative humidity, for about 24 hours. The tube is found to be very flexible, and fits into a U-shaped channel opposite a moving surface which slides relative to the open face of said channel. When gaseous helium is passed through the tube at room temperature and a pressure of 85 psi, helium transpiration through the seal is observed. Transpiration cooling is determined in accordance with the environment in which the seal is utilized. Appropriate gas temperature and pressures will be determined for the extent of transpiration cooling required, and are within the skill of the practitioners to determine.
It is to be understood that the above description of the present invention is susceptible to considerable modification, change, and adaptation by those skilled in the art, and that such modifications, changes, and adaptations are to be considered within the scope of the invention, which is set forth by the appended claims.
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Transpiration cooled ceramic fiber seals are provided for high temperature use, said seals providing transpiration cooling by passage of a cooling medium through controlled porosity.
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BACKGROUND OF THE INVENTION
The present invention relates generally to a specially formed fabric having differential densities, and more particularly to a fabric that is specially designed in a manner that permits it to be readily formed into expandable honeycomb panels that can be utilized to provide practical, aesthetically pleasing decorative window coverings.
Colson U.S. Pat. No. 4,450,027 discloses a method and apparatus for forming expandable honeycomb insulation panels from thin film plastic material, whereby the panels have desirable energy conservation characteristics by virtue of their insulating and heat collective properties, as well as being aesthetically pleasing when used as window coverings. Briefly summarized, such patent discloses the concept of continuously creasing and folding strips of thin plastic film into an open sided tubular structure, then heat setting the folds in the film, and applying liquid adhesive to the portions of the film to be joined together to form the expandable honeycomb configuration.
Efforts have also been made to form expandable honeycomb panels from textile fabric materials rather than plastic to enhance the aesthetic appeal of the panels while sacrificing to some extent the energy conservation function of the panels. In attempting to form these panels from conventional thin fabric materials, a significant problem has been presented in terms of using a liquid adhesive to join the fabric to itself to provide the desired expandable honeycomb configuration.
When a textile fabric is used to make these panels, it must be quite sheer to provide the desired aesthetic and functional qualities normally associated with conventional sheer curtains and the like, but the open-mesh characteristic of this type of sheer fabric makes it virtually impossible to apply a liquid adhesive to the fabric solely at the required points of fabric juncture without also having the adhesive flow through the open-mesh sheer fabric to join other parts of the fabric to itself in a manner that will prevent proper expansion of the plurality of the individual honeycomb segments that make up the entire window panel. More specifically, when the individual segments are properly folded for ultimate expansion and contraction, the end portion of each such folded segment must be adhesively joined only to the center portion of the next adjacent segment, without any adhesive seeping through this point of juncture to cause adhesion at the end portions of an individual segment to the center portion of the same segment, which would prevent the necessary expansion of the individual segment when the final panel is used as a window covering. However, because of the aforesaid open-mesh construction of conventional sheer fabric, it is virtually impossible to prevent this seepage of adhesive during production of panels in high volume, commercially feasible manufacturing equipment.
In accordance with the present invention, a specially designed differential density fabric is provided which overcomes the above-described practical drawbacks of using a sheer textile fabric to form an expandable honeycomb window panel.
SUMMARY OF THE INVENTION
The textile fabric of the present invention comprises a plurality of adjacent strips of fabric extending parallel to one another, and each strip is formed with a longitudinally extending center portion having a predetermined width and a predetermined high fabric density, two end portions extending generally parallel to the center portion in spaced relation thereto, each such end portions also having a predetermined high fabric density and having a width substantially one-half the width of the center portion, and two intermediate portions extending respectively between said center portion and each of said end portions, said intermediate portions being formed of an open-mesh fabric having a substantially lesser density than said predetermined fabric density of the center portion and the two end portions.
The predetermined fabric density for the center portion and the two end portions of each strip is sufficiently high so that when a measured quantity of liquid adhesive is applied to join the two end portions of one strip to the center portion of an adjacent strip, such adhesive will not seep through the joined center portion and end portions.
The two intermediate portions of each strip may be formed of identical fabric construction or they may be formed of contrasting colors and/or contrasting degrees of sheerness (e.g. one being generally opaque and the other being generally translucent).
In the preferred embodiment of the present invention, a plurality of strips are formed in parallel relation to one another as one sheet of fabric material, with at least one of the end portions of each of said strips being joined to an adjacent end portion of another of such strips by connecting yarns having a sufficiently low density to permit each such strip to be separated from an adjacent strip by tearing or cutting without damage to the structural integrity of the separated strips.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a sheet of textile fabric formed according to the present invention;
FIG. 2 is a detail view illustrating the manner in which one strip of fabric material is folded before being joined by an adhesive to an adjacent strip of material;
FIG. 3 is a detail view illustrating the manner in which one folded strip of fabric material is joined to an adjacent strip;
FIG. 4 illustrates a panel formed from the textile fabric material of the present invention in its expanded configuration; and
FIG. 5 illustrates the panel of FIG. 4 in its contracted configuration.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Looking now in greater detail at the accompanying drawings, FIG. 1 is a plan view of a portion of a sheet of textile fabric constructed in accordance with the present invention. This sheet of fabric includes a plurality of identical strips 10 extending in parallel relation to one another.
Each such strip 10 is comprised of a longitudinally center portion 12 having a predetermined relatively high fabric density of a magnitude to be discussed below. Each strip 10 also includes two end portions 14 extending parallel to the center portion 12 and having a fabric density equal to that of the center portion, each end portion 14 having a width that is approximately one-half of the width of the center portion 12. Intermediate portions 16 extend, respectively, between the center portion 12 and each or the end portions 14, each said intermediate portion 16 being formed of an open-mesh fabric having a substantially lesser fabric density than that of the center portion 12 and the end portion 14.
Each strip 10 is joined to an adjacent strip 10 by a small number of yarns 18 extending between one end portion 14 of one strip 10 to an adjacent end portion 14 of the next strip 10 as illustrated in FIG. 1, the size and number of the yarns 18 being selected to have sufficient strength to maintain the strips 10 as an integral sheet of fabric during manufacture and handling thereof, but being sufficiently fragile to permit the adjacent strips 10 to be readily separated from one another by tearing or cutting without damage to the structural integrity of the strips during or after such separation. For purposes of illustration, one of the strips 10 is shown partially separated from an adjacent strip 10 along the separation line provided by the connecting yarns 18.
To form an expandable honeycomb panel of the type described above, suitable equipment, which forms no part of the present invention, is employed to separate the strips 10 from one another and manipulate the individual strips 10 in a manner that permits them to be joined together by a conventional liquid adhesive to provide a composite panel. As best illustrated in FIG. 2, each strip 10 is manipulated so that the two intermediate portions are folded at their approximate longitudinal mid-lines, whereby the two end portions 14 are positioned adjacent one another, and in an overlapping and contiguous position with respect to the center portion 12 of the strip 10, it being noted that since the width of each end portion 14 is approximately one-half of the width of the center portion 12, the combined width of the two end portions 14 is the same as that of the center portion 12 in the overlapping disposition illustrated in FIG. 2.
The next step in forming the panel is to join one strip 10 to another, this step being illustrated somewhat diagrammatically in FIG. 3 where the individual strips 10 are shown in a slightly expanded disposition for clarity of illustration, but during actual joining of adjacent strips during manufacture it is to be noted that the strips 10 would be fully contracted with the overlapping portions being immediately adjacent one another. As illustrated in FIG. 3, a measured quantity of a suitable liquid adhesive 20 is ejected or otherwise laid between the center portion 12 of one strip 10, and the two contiguous end portions 14 of the next adjacent strip 10 so that the adjacent strips 10 will be joined by the adhesive at this point.
In joining adjacent strips 10 together in this manner, it is important that the adhesive 20 only join the center portion 12 of one strip 10 to the end portions 14 of the next adjacent strip 10, and that this adhesive 20 not be permitted to seep through such joined portions in a manner that would result in the center portion 12 of any one strip 10 being joined to the end portions 14 of the same strip 10 because the result would prohibit the individual strips from assuming an expanded disposition during use, such expanded disposition being discussed in greater detail below. To avoid such seepage of the adhesive 20, both the center portion 12 and the two end portions 14 of each strip 10 are specially formed with a predetermined high fabric density that is high enough to prevent any seepage therethrough of the measured quantity of adhesive that is applied between the center portions 12 and the end portions 14 of the adjacent strips 10 as explained above.
After a desired number of strips 10 have been formed and joined as described above, the resulting honeycomb of fabric may be mounted between an upper slat 22 and a lower slat 24 as illustrated in FIGS. 4 and 5 to complete the construction of a window panel 26. Because of the formation of the honeycomb fabric, the window panel 26 may be mounted in a window in a manner similar to that of venetian blinds so that it can be raised and lowered between a fully expanded disposition as illustrated in FIG. 4 or a fully contracted disposition as illustrated in FIG. 5, or any intermediate disposition. When the honeycomb fabric is fully or partially expanded, it will be noted that each individual strip 10 is formed in a generally diamond shape with only the very sheer fabric of the intermediate portions 16 of each strip 10 being generally visible, and with the higher density center portion 12 and end portions 14 of the strips 10 not being noticeably visible, so that the window panel 26 provides an attractive and aesthetically pleasing appearance generally similar to conventional sheer curtains but with the added decorative shape provided by the honeycomb construction of the fabric.
The construction of the fabric of the present invention also makes it quite versatile in terms of both aesthetic appeal and functionality. For example, when the strips 10 are formed, one of the intermediate portions 16 of each strip 10 may be made of one color (e.g. light blue) and the other intermediate portion 16 of each strip 10 may be made of a contrasting color (e.g. darker blue). When the construction of the window panel 26 is completed as illustrated in FIG. 4, it will be noted that all of the corresponding colored intermediate portions 16 of the various strips 10 are presented on one side of the finished window shade 26 to provide a consistent color on that side, whereas the other group of contrasting colored intermediate portions 16 are presented on the opposite side of the window panel 26, so that the user can select the desired color that will be visible by mounting the window panel 26 in the window with one side or the other exposed to normal viewing. Similarly, striped effects for the window panel 26 can be obtained by making the intermediate portions 16 of some strips 10 of one color and making the corresponding intermediate portions 16 of other strips 10 of a contrasting color or colors. Yet another variation would be to knit or otherwise form one intermediate portion 16 of each strip 10 with a very sheer fabric density so that it will be translucent and form the other intermediate portion 16 of each strip 10 with a fabric construction that is opaque. While the examples set forth above are illustrative of the versatility of the fabric construction of the present invention, it will be understood that many other variations are possible, all of which adds to the commercial acceptance of the window shades as both functional and highly decorative cover for windows and the like.
In a typical or representative strip 10 of fabric constructed in accordance with the present invention, the center portion 12 and the two end portions 14 of each strip 10 are formed of two individual warp knitting systems of 20 denier yarn that are knitted together with another individual warp knitting system of 78 denier yarn laid into the knitted fabric, and the intermediate portions 16 are formed of two individual warp knitting systems of 20 denier yarn knitted together. In the resulting fabric, the weight of the sheer intermediate portion is 0.98 ounces per square yard, and the weight of more dense end portions 14 and the center portion 12 is 2.28 ounces per square yard, over twice as dense as the intermediate portion 16. In terms of thickness, the intermediate portions 16 are about 0.008-inch in thickness, and the end portions 14 and center portion 12 have a thickness of about 0.012-inch.
It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limmit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.
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A sheer textile fabric for use in forming expandable honeycomb window panels, such fabric comprising a plurality of strips of fabric, each strip having a center portion and two spaced end portions formed with a sufficient fabric density to avoid the seepage therethrough of a liquid adhesive used to join the center portion of one strip to the end portions of another strip, and each strip having intermediate portions extending between the center portion and the two end portions thereof, such intermediate portions being formed of a sheer fabric having a fabric density substantially less than the fabric density of the center and end portion. These intermediate portions may be made of varying colors and/or fabric densities to thereby vary the appearance and/or functional aspects of the window panels formed from the textile fabric.
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RELATED APPLICATIONS
This application claims priority to U.S. provisional application Ser. No. 62/232,696, filed on Sep. 25, 2015, the entire contents of which are incorporated herein by reference.
BACKGROUND
Inorganic-organic hybrid materials that include metal-organic frameworks (“MOFs”) have attracted intensive attention in recent years. MOFs are known to display the highest reported specific surface area among all porous materials, and can be synthesized from a theoretically infinite combination of metals and linkers. This has made them promising candidates for a diverse range of applications including sensing, separation, and drug delivery.
To establish a thorough structure-property relationship for rational MOF design, numerous studies have explored different functions of various MOFs (e.g., such as for gas storage, sensing, and separation), however few studies have focused on MOF semiconductor materials and properties. Research aimed at exploring the tuning of semiconductor behaviors of MOFs have generally focused on band gap energy variation by changing the different metals and/or linkers involved in the synthesis (see for example Yang, L. M.; Fang, G. Y.; Ma, J.; Ganz, E.; Han, S. S. Cryst. Growth Des. 2014, 14, 2532-2541, and Hendon, C. H.; Tiana, D.; Fontecave, M.; Sanchez, C.; D'arras, L.; Sassoye, C.; Rozes, L.; Mellot-Draznieks, C.; Walsh, A. J. Am. Chem. Soc. 2013, 135, 10942-10945). Some structure to property relationship studies have shown that varying organic linkers can significantly impact the bulk optical band gap energy (see for example Gascon, J.; Hernández-Alonso, M. D.; Almeida, A. R.; van Klink, G. P. M.; Kapteijn, F.; Mul, G. ChemSusChem 2008, 1, 981-983).
Numerous studies have been performed focusing on varying the ligand to change optical band gap energy, however these attempts were mostly made before synthesis (see for example Flage-Larsen, E.; Royset, A.; Cavka, J. H.; Thorshaug, K. J. Phys. Chem. C 2013, 117, 20610-20616, and Lin, C.-K.; Zhao, D.; Gao, W.-Y.; Yang, Z.; Ye, J.; Xu, T.; Ge, Q.; Ma, S.; Liu, D.-J. Inorg. Chem. 2012, 51, 9039-9044). Furthermore, the modification of the optical band gap energy through internal in-situ reactions using controllable external stimuli has not been widely explored.
SUMMARY OF THE INVENTION
Some embodiments include a metal-organic framework material preparation method comprising, 1) in a first step, forming a first solution by dissolving ZrOCl 2 .8H 2 O in dimethylformamide (DMF) and formic acid, and 2) in a second step, mixing and dissolving 1,4-phenylenediacrylic acid in a second solution of dimethylformamide (DMF) and trimethylamine; 3) in a third step, at least partially mixing the first and second solutions to form a mixture; and 4) in a fourth step, sealing the mixture in an autoclave and heating the mixture above ambient for a specified period of time to prepare ZrPDA metal-organic framework.
In some embodiments, the second step occurs after completion of the first step. In some further embodiments, the second step is performed at least partially concurrently with the first step. In some embodiments, during the fourth step, the mixture is heated to a temperature between ambient temperature and 200° C.
In some embodiments, during the fourth step, the mixture is heated to about 120° C. In some embodiments, the specified period of time is between about 24 hours and 1 week. In some embodiments, the specified period of time is about 24 hours. In some further embodiments, in a fifth step, the ZrPDA metal-organic framework is washed with dimethylformamide (DMF). In further embodiments, the ZrPDA metal-organic framework is washed with dimethylformamide (DMF) at least twice. In some other embodiments, the ZrPDA metal-organic framework is washed with dimethylformamide (DMF) three times per day for three days. Some embodiments include a sixth step where the ZrPDA metal-organic framework is soaked in acetone and solvent exchanged for a specified exchange period. In some embodiments, the solvent exchange occurs at least twice. In some embodiments, the exchange period is three days, and the acetone is changed three times per day. In some embodiments, the ZrPDA metal-organic framework is heated to about 100° C. in a vacuum oven.
Some embodiments include a method of preparing a phototuned metal-organic framework comprising: 1) in a first step, forming a first solution by dissolving ZrOCl2.8H2O in dimethylformamide (DMF) and formic acid, and 2) in a second step, mixing and dissolving 1,4-phenylenediacrylic acid in a second solution of dimethylformamide (DMF) and trimethylamine; and 3) in a third step, at least partially mixing the first and second solutions to form a mixture; and 4) in a fourth step, sealing the mixture in an autoclave and heating the mixture to above ambient temperature for a specified period of time to prepare ZrPDA metal-organic framework; and 5). in a fifth step, extracting the ZrPDA metal-organic framework and at least partially reacting to a specified degree at least some of ZrPDA metal-organic framework through [2+2] cycloaddition reactions, wherein the specified degree is tunable based at least in part on at least one of the intensity of UV radiation, the exposure time, and the UV wavelength.
In some embodiments, the specified time is between 24 hours and 1 week. In some further embodiments, in the fourth step, the mixture is heated to between 50° C. and 200° C. In some embodiments, the UV wavelength is about 302 nm. In some further embodiments, the exposure time is greater than zero and less than 60 minutes. In some further embodiments, the exposure time is between about 60 minutes and 2 hours.
DESCRIPTION OF THE DRAWINGS
FIG. 1A illustrates a ZrPDA formation reaction in accordance with some embodiments of the invention.
FIG. 1B illustrates an FTIR spectra of ZrPDA with varying UV exposure times in accordance with some embodiments of the invention.
FIG. 1C shows alternative linker structures to 1,4-phenylenediacrylic acid in accordance with some other embodiments of the invention.
FIG. 2A shows UV-VIS spectra of activated ZrPDA with varying UV exposure time in accordance with some embodiments of the invention.
FIG. 2B shows the optical band gap energies of activated ZrPDA with 0 minute, 60 minutes, and 120 minutes of UV exposure in accordance with some embodiments of the invention.
FIG. 2C shows the optical band gap energies of pure ligand with 0 minute, 60 minutes, and 120 minutes of UV exposure in accordance with some embodiments of the invention.
FIG. 3A shows photoluminescence spectra of diluted H 2 PDA in accordance with some embodiments of the invention.
FIG. 3B shows photoluminescence spectra of ZrPDA before UV exposure in accordance with some embodiments of the invention.
FIG. 3C shows photoluminescence spectra of ZrPDA with 120 minutes UV irradiation in accordance with some embodiments of the invention.
FIG. 4A shows powder XRD patterns of ZrPDA, as-synthesized, and soaked in water for 1 week, 2 weeks, and 3 weeks, and soaked in water for 4 weeks in accordance with some embodiments of the invention.
FIG. 4B shows FT-IR spectra from 2000 cm −1 to 400 cm −1 of ZrPDA with varying time of soaked under water in accordance with some embodiments of the invention.
FIG. 5 shows a powder XRD pattern of the ZrPDA in accordance with some embodiments of the invention.
FIG. 6 shows an N 2 adsorption/desorption isotherm in accordance with some embodiments of the invention.
FIG. 7 illustrates thermogravimetric (TGA) curves of as-synthesized and activated ZrPDA samples accordance with some embodiments of the invention.
DETAILED DESCRIPTION
Before any embodiments of the invention are explained 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 components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention. Thus, embodiments of the invention are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.
Some embodiments of the invention include the use functional molecules that can respond to various external stimulus (e.g., including, but not limited to pH changes, light irradiation, temperature change, pressure change, etc.,) By introducing smart molecules into frameworks, one or more properties of the material can be influenced or changed using one or more external stimuli.
Embodiments of the invention described herein include Zirconium-based MOFs synthesized with a photo-active linker molecule that is able to produce a microporous material with a specific surface area higher than 1000 m 3 /g. Further, the optical band gap energy can be varied by UV irradiation in solid state. In contrast to the low stability of conventional metal-organic frameworks, Zirconium-based MOFs synthesize using the methods described herein can be highly moisture or water stable. For example, the crystal structure can remain substantially stable under water for at least 672 hours. The tunable optical band gap energy, high specific surface area, and high hydrostability of these materials provide use in a wide range of applications, including, but not limited to photocatalysis, semiconductors, and energy harvesting.
Embodiments of the invention described herein include Zirconium-based MOFs synthesized with 1,4-phenylenediacrylic acid (H 2 PDA). 1,4-phenylenediacrylic acid (H 2 PDA) is just one of a number of compounds containing cinnamoyl moieties that undergo a [2+2] cycloaddition reaction under UV irradiation. Using the methods described therein, Zirconium-based MOFs that are hydro-stable and with in-situ photo-tunable properties can be synthesized. Conventional commercially available materials were used as received without any further purification to produce Zirconium-1,4-phenylenediacrylic acid (ZrPDA) that can undergo cycloaddition. For example, referring to FIG. 1A , illustrating a ZrPDA, some embodiments include the synthesis of Zirconium-based MOFs (shown as 1a, 1b), that can undergo photodimerization using UV irradiation to form a [2+2] cycloaddition product 5 through a [2+2] cycloaddition of cinnamoyl groups (shown as 3).
In some embodiments, ZrPDA precursor materials can include Zirconium oxychloride octahydrate (ZrOCl 2 .8H 2 O), Formic Acid, and 1,4-Phenylenediacrylic Acid (H 2 PDA) from Sigma Aldrich. N,N-Dimethylformamide (DMF) and acetone can be sourced from Fisher Scientific, and Triethylamine (TEA) can be sourced commercially from Alfa Aesar. Some embodiments include methods of synthesis of ZrPDA compounds including a first step, where ZrOCl 2 .8H 2 O (about 0.161 g, 0.5 mmol) can be dissolved in a mixture of about 15 mL of DMF and about 2.3 mL of formic acid. In a second sequential or concurrent step, 1,4-phenylenediacrylic acid (about 0.109 g, 0.5 mmol) can be mixed and dissolved in a solution containing about 15 mL of DMF and about 0.15 mL of trimethylamine. In a third step, the two solutions (ZrOCl 2 .8H 2 O/DMF/formic acid and 1,4-phenylenediacrylic acid/DMF/trimethylamine) can be mixed and sealed in a Teflon lined stainless steel autoclave. In some embodiments, the autoclave can be heated to about 120° C. and held for about 24 hours. Subsequently, the synthesized samples can be washed with DMF three times a day for three days. In some embodiments, samples can be soaked in acetone for solvent exchange, and the solvent changed three times a day for three days. Further, in some embodiments, the sample can be heated to about 100° C. in vacuum oven and maintained for 24 hours. In some other embodiments of the invention, other metals can be used in place of or in addition to Zirconium. For example, in some embodiments, Titanium and/or Hafnium can be used. In some further embodiments, other transition metals and/or group 13 and/or group 14 metals can be used including, but not limited to, Zinc, Copper, Nickel, Cobalt, Iron, Manganese, Chromium, Vanadium, Cadmium, Aluminum, Gallium, Indium, Tin, Scandium, Yttrium, and/or any lanthanide series metal.
In some further embodiments, the ZrPDA synthesized using the methods described above can be exposed to UV irradiation (e.g., with a wavelength of about 302 nm and with varying exposure time). Using a AUV-Vis spectrometer, FT-IR spectrometer, and spectrofluorometer, the change of optical band gap energy of ZrPDA can be monitored. In some embodiments, the optical band gap energy of ZrPDA can be lowered after being exposed under UV irradiation as described. Further, FTIR, XRD, and photoluminescence of the ZrPDA following UV exposure causing [2+2] cycloaddition can be used to characterize the development of photodimerized ZrPDA (shown as 5 in FIG. 1A ). For example, FIG. 1B illustrates an FTIR spectra of various ZrPDA materials with varying UV exposure times in accordance with some embodiments of the invention. The exposure times include no exposure (shown as curve 10 a ), a 5 minute UV exposure time (shown as curve 10 b ), a 10 minute UV exposure (shown as curve 10 c ), a 15 minute UV exposure (shown as curve 10 d ), a 20 minute UV exposure (shown as curve 10 e ), a 30 minute UV exposure (shown as curve 10 f ), a 40 minute UV exposure (shown as curve 10 g ), a 50 minute UV exposure (shown as curve 10 h ), a 60 minute UV exposure (shown as curve 10 i ), a 90 minute UV exposure (shown as curve 10 j ), and a 120 minute UV exposure (shown as curve 10 k ).
FIG. 1C shows various linker structures to 1,4-phenylenediacrylic acid in accordance with some embodiments of the invention. For example, in some embodiments, the UV active linker molecule can comprise linker 1 (shown as structure 13 ) as shown with various substitutions including one or more of those shown in Table 1 below:
TABLE 1
linkers based on Ligand 1 of FIG. 1C
R
Name
H
1,4-Phenylenediacrylic acid
Cl
(2E,2′E)-3,3′-(perchloro-1,4-phenylene)diacrylic acid
Br
(2E,2′E)-3,3′-(perbromo-1,4-phenylene)diacrylic acid
CH 3
(2E,2′E)-3,3′-(2,3,5,6-tetramethyl-1,4-phenylene)diacrylic acid
NH 2
(2E,2′E)-3,3′-(2,3,5,6-tetraamino-1,4-phenylene)diacrylic acid
NO 2
(2E,2′E)-3,3′-(2,3,5,6-tetranitro-1,4-phenylene)diacrylic acid
OH
(2E,2′E)-3,3′-(2,3,5,6-tetrahydroxy-1,4-phenylene)diacrylic acid
B(OH) 2
(2E,2′E)-3,3′-(2,3,5,6-tetraborono-1,4-phenylene)diacrylic acid
In some further embodiments, the UV active linker molecule can comprise linker 2 (shown as structure 15 ) as shown with various substitutions including one or more of those shown in Table 2 below:
TABLE 2
Alternative linkers based on Ligand 2 of FIG. 1C
R
Name
H
1,4-bis(3-(4-pyridinyl)propenyl)benzene
Cl
4,4′-((2E,2′E)-(perchloro-1,4-phenylene)bis(prop-2-ene-3,1-
diyl))dipyridine
Br
4,4′-((2E,2′E)-(perbromo-1,4-phenylene)bis(prop-2-ene-3,1-
diyl))dipyridine
CH 3
4,4′-((2E,2′E)-(2,3,5,6-tetramethyl-1,4-phenylene)bis(prop-2-
ene-3,1-diyl))dipyridine
NH 2
3,6-bis((E)-3-(pyridin-4-yl)prop-1-en-1-yl)benzene-
1,2,4,5-tetraamine
NO 2
4,4′-((2E,2′E)-(pernitro-1,4-phenylene)bis(prop-2-ene-
3,1-diyl))dipyridine
OH
3,6-bis((E)-3-(pyridin-4-yl)prop-1-en-1-yl)benzene-
1,2,4,5-tetraol
B(OH) 2
3,6-bis((E)-3-(pyridin-4-yl)prop-1-en-1-yl)benzene-
1,2,4,5-tetrayl)tetraboronic acid
In some other embodiments, the UV active linker molecule can comprise linker 3 (shown as structure 17 ) as shown with various substitutions including one or more of those shown in Table 3:
linkers based on Ligand 3 of FIG. 1C
R
Name
H
1,4-bis((E)-2-(pyridinyl-4-yl)vinyl)benzene
Cl
4,4′-((1E,1′E)-(perchloro-1,4-phenylene)bis(ethene-2,1-
diyl))dipyridine
Br
4,4′-((1E,1′E)-(perbromo-1,4-phenylene)bis(ethene-2,1-
diyl))dipyridine
CH 3
4,4′-((1E,1′E)-(2,3,5,6-tetramethyl-1,4-phenylene)bis
ethene-2,1-diyl))dipyridine
NH 2
3,6-bis((E)-2-(pyridin-4-yl)vinyl)benzene-1,2,4,5-
tetraamine
NO 2
4,4′-((1E,1′E)-(pernitro-1,4-phenylene)bis(ethene-2,1-
diyl))dipyridine
OH
3,6-bis((E)-2-(pyridin-4-yl)vinyl)benzene-
1,2,4,5-tetraol
B(OH) 2
(3,6-bis((E)-2-(pyridin-4-yl)vinyl)benzene-
1,2,4,5-tetrayl)tetraboronic acid
Further, FIG. 2A shows UV-VIS spectra of activated ZrPDA with varying UV exposure time in accordance with some embodiments of the invention. The exposure times include no exposure (shown as curve 20 a ), 5 minute exposure (shown as curve 20 b ), 10 minute exposure (shown as curve 20 c ), 15 minute exposure (shown as curve 20 d ), 20 minute exposure (shown as curve 20 e ), 30 minute exposure (shown as curve 20 f ), 40 minute exposure (shown as curve 20 g ), 50 minute exposure (shown as curve 20 h ), 60 minute exposure (shown as curve 20 i ), 90 minute exposure (shown as curve 20 j ), and 120 minute exposure (shown as curve 20 k ).
FIG. 2B shows the optical band gap energies of activated ZrPDA with 0 minute (shown as curve 24 a ), 60 minutes (shown as curve 24 b ), and 120 minutes of UV exposure (shown as curve 24 c ), in accordance with some embodiments of the invention. FIG. 2C shows the optical band gap energies of pure ligand with 0 minute (shown as curve 26 a ), 60 minutes (shown as curve 26 b ), and 120 minutes of UV exposure (shown as curve 26 c ), in accordance with some embodiments of the invention. FIG. 3A shows photoluminescence spectra 30 of diluted H 2 PDA in accordance with some embodiments of the invention. FIG. 3B shows photoluminescence spectra 33 of ZrPDA before UV exposure in accordance with some embodiments of the invention. FIG. 3C shows photoluminescence spectra 36 of ZrPDA with 120 minutes UV irradiation in accordance with some embodiments of the invention.
The hydrostability of ZrPDA synthesized using the methods described herein was verified by immersion under water for 672 hours. The tested samples were analyzed by FT-IR spectrometer and high resolution X-ray diffractometer showing the stability of its crystal structure. For example, FIG. 4A shows powder XRD patterns of ZrPDA, as-synthesized (shown as curve 40 a ), and soaked in water for 1 week (shown as curve 40 b ), 2 weeks (shown as curve 40 c ), 3 weeks (shown as curve 40 d ), and soaked in water for 4 weeks (shown as curve 40 e ) in accordance with some embodiments of the invention. FIG. 4B shows FTIR spectra from 2000 to 400 cm −1 of ZrPDA with varying time of soaked under water in accordance with some embodiments of the invention, with the soaking times as described for curves 40 a , 40 b , 40 c , 40 d , and 40 e shown in FIG. 4A .
FIG. 5 shows a powder XRD pattern 50 of the ZrPDA in accordance with some embodiments of the invention. FIG. 6 shows an N 2 adsorption isotherm (curve 60 a ) and a an N 2 desorption isotherm (curve 60 b ) in accordance with some embodiments of the invention. FIG. 7 illustrates thermo-gravimetric (TGA) curves of as-synthesized (shown as curve 70 b ) and activated ZrPDA samples (shown as curve 70 a ) in accordance with some embodiments of the invention.
It will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. Various features and advantages of the invention are set forth in the following claims.
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Some embodiments include a method of preparing a phototuned metal-organic framework by forming a first solution by dissolving ZrOCl 2 .8H 2 O in dimethylformamide (DMF) and formic acid, mixing and dissolving 1,4-phenylenediacrylic acid in a second solution of dimethylformamide (DMF) and trimethylamine, and at least partially mixing the first and second solutions to form a mixture. The method further includes sealing the mixture in an autoclave and heating the mixture to above ambient temperature for a specified period of time to prepare ZrPDA metal-organic framework, and extracting the ZrPDA metal-organic framework and at least partially reacting to a specified degree at least some of ZrPDA metal-organic framework through [2+2] cycloaddition reactions. The specified degree can be tunable based at least in part on at least one of the intensity of UV radiation, the exposure time, and the UV wavelength.
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FIELD OF THE INVENTION
The invention relates to a container lock with a housing and within it a bolt that can be displaced by actuating a handle, as well as with an insertion shaft for inserting a coin, with a scanning device for scanning the diameter of the coin inserted in the insertion shaft as far as a scanning position, so that the scanning device interacts with a blocking device in such a way that the bolt can be displaced only for a coin having a correct diameter.
BACKGROUND OF THE INVENTION
A container lock of this type is known in the art from DE 109 32 516 A1. The previously known lock for a locking installation includes a housing, a bolt that can be displaced within the housing by a handle, so that the bolt is held in its reclosed position by means of a blocking device. Said blocking device is released to pre-lock the bolt when a coin having a correct diameter is inserted in an insertion shaft. The lock comprises a scanning device for scanning the diameter of the coin. If the lock is reclosed again by actuation of a handle, the coin falls into a return shaft.
DE 10 2006 034 292 discloses a container lock in which a secret code must be entered in a lock to reclose the bolt. The secret code can be entered by a keyboard. The lock is also capable of reading a transponder in which the secret code is stored.
DE 195 15 765 A1 discloses a coin deposit lock that is used for supermarket carts. The lock comprises an insertion shaft. The unlocking mechanism is released by inserting the coin.
It is the object of the invention to improve a generic container lock for advantageous functioning.
SUMMARY OF THE INVENTION
The object is fulfilled through the invention as indicated in the claims, wherein every claim constitutes an independent solution of the object of the invention and can be combined with every other claim.
It is proposed, first and essentially, that the scanning device should be configured as a fixing jaw that firmly prevents the coin that is entering the insertion shaft in the scanning position while still partially accessible from outside from being withdrawn with the bolt pre-locked. According to the invention the coin is inserted into the insertion shaft of the lock housing as far as the scanning position. In this scanning position the scanning device scans the diameter of the coin. The position here is a maximum insertion depth in which the coin can still be gripped from outside but, because of the fixing function of the fixing jaw, cannot be withdrawn from the insertion shaft. The coin is preferably held in a form-locking mounting in the scanning position. The coin is thus preferably partially surrounded as if by a pincer, so that a fixing jaw is configured by an oscillating lever that can rotate around an axle in the housing. An additional fixing jaw can be combined firmly with the housing. The two fixing jaws surround the coin beyond its area of maximum diameter, so that it can be withdrawn again only from the insertion shaft after a separating motion of the two fixing jaws. No actuation of the bolt occurs with the coin itself. Said bolt can preferably be displaced perpendicularly to the coin-inserting direction. The oscillating lever preferably comprises a support arm, on whose ends the axle is fulcrumed. The fixing jaw preferably extends down from the supporting limb in an essentially perpendicular direction. The oscillating lever forms a rotation recess flanked by at least one blocking flank. A rotation stud attached to the bolt can engage in this rotation recess when an appropriate coin is inserted into the insertion shaft. A guide groove can connect with the rotation recess. Said guide groove extends, when an appropriate coin is inserted, in a direction essentially parallel to the displacement direction of the bolt. While the movable fixing jaw extends essentially perpendicular to the displacement direction of the bolt, the supporting limb extends parallel to the displacement direction of the bolt. The stationary fixing jaw can become movable. It can be secured to the lock housing, for instance by means of screws. By releasing the screws, the distance between the fixing jaws can be adjusted in the release position. The insertion shaft preferably comprises a convexity in which a portion of the inserted coin is located. The convexity extends over a surface that is large enough so that the coin can be grasped between two fingers to allow it to be extracted from the insertion shaft. Essentially the coin is inserted into the insertion shaft only for scanning its diameter. While the coin is being inserted, only the blocking device is displaced from a blocking position into a release position. No bolt displacement is possible by means of the coin. In an elaboration of the invention, the lock housing comprises a blocking element. Said blocking element is accessible from the housing exterior. Said blocking element is capable of fixing the oscillating lever or the rotation recess in a position in which the rotation recess lies in the path of the rotation stud. Thus, when blocked, the lock can be actuated without deposit function. The blocking element can take the form of a blocking stud, which in blocked position engages in an end portion of the guide groove that connects with the rotation recess, in order to make the oscillating lever stationary in the rotation position corresponding to the release position. The bolt pre-locking occurs in known manner by means of a crankshaft, which is actuated by a handle. Said crankshaft engages in an engagement opening of the bolt in order to pre-lock the bolt. The lock, in addition, comprises a blocking device with which the bolt can be kept in the pre-closed position. The blocking device, in addition, can also hold the bolt in the re-locked position. The blocking device can be brought from a blocked position into a release position. This can occur in known manner, for instance by actuating a key. However, the blocking device is preferably released by reading an electronic secret code, and the secret code is kept in a transponder, which in known manner is read by the closing device. In addition it can be foreseen that the secret code is a PIN, which is entered by a keyboard. In addition, the lock can comprise a fingerprint reading device in order to read a user's fingerprint. Upon correctly entering the secret code, the blocking device is displaced into the release position. The bolt can be pre-locked. The blocking device holds it in the pre-locked position until the correct secret code is again entered. The lock can include a cashier function. For this purpose the lock can be opened with an overriding secret code. In the re-closed bolt position, the coin can be withdrawn. By means of an auxiliary tool that is inserted into the insertion shaft, the two jaws are moved apart to the correct distance, so that the rotation stud can engage in the rotation recess. The fixing jaw can be temporarily blocked in this position by means of the blocking device. It is foreseen that, when the bolt is completely pre-locked, the rotation stud can move the blocking device out of the blocked position. This can occur by pressure on the blocking pin. Said blocking pin is then moved out of the guide groove. The oscillating lever can also be made stationary by means of a screw. For this purpose the oscillating lever, and in particular the fixing jaw formed by the oscillating lever, can configure a screw-in opening into which the screw can be inserted and turned. As a result, the scanning device can be put out of operation for an extended period so that the lock can also be operated without deposit function. In an elaboration of the invention it is foreseen that the scanning device interacts with an electric scanner or a switch. Depending on the actuation position of the scanning device, an electric circuit is closed or opened. As a result an electric signal can be provided, which changes its condition when an appropriate coin is inserted into the insertion shaft. This electric signal can be used to block or release the bolt. For this purpose it is possible to use an electric magnet that can be already situated in the lock housing. Said magnet can be moved into a release position when the scanning device emits a corresponding electric signal. In an elaboration of the invention it is foreseen that the coin diameter is immediately scanned by a scanner.
An embodiment of the invention is explained hereafter with reference to appended illustrations.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the housing in perspective frontal view as well as the front plate of a container lock in a perspective depiction.
FIG. 2 is a backward perspective depiction of the container lock.
FIG. 3 shows a front view of the lock with the lock door indicated.
FIG. 4 shows the lock assembly in the housing with the bolt displaced and with no coin inserted.
FIG. 5 shows a depiction as in FIG. 4 with an appropriate coin inserted.
FIG. 6 shows a depiction as in FIG. 4 with the blocking element activated.
FIG. 7 shows an enlarged view of detail VII of FIG. 6 .
FIG. 8 shows an individual view of the scanning device.
FIG. 9 shows a section along the line IX-IX.
FIG. 10 shows the bolt in a perspective view.
DETAILED DESCRIPTION OF THE INVENTION
The container lock shown in the illustrations can be affixed to a container door 25 . It comprises a housing 1 , which can be affixed to the container door 25 on the inside of the container. The lock comprises a front plate 26 , which is affixed on the outside of the door. The front plate 26 comprises a handle 27 by which a crankshaft 35 can be rotated in order to displace a bolt 3 positioned in the housing 1 in a direction that displaces the bolt. The front plate 26 also comprises a scanning field 28 by which a numeric code can be entered.
A transponder reading device can also be installed in the front plate 26 or in the handle 27 in order to read a transponder. In addition, the lock can also be connected with a fingerprint reading device.
The housing 1 consists of a synthetic material. The bolt 3 is preferably of metal construction. Found on the underside of the bolt is a blocking slot 30 that forms two blocking steps 31 , 34 . A blocking extension 32 of a blocking lever 33 engages in the blocking slot 30 . The blocking lever 33 can be rotated by means of an electromagnet 29 . Said lever can assume a blocking position, in which, when the bolt is pre-locked, the blocking extension 32 lies in front of the blocking step 31 so that the pre-locked bolt cannot be relocked by the handle 27 . As an alternative to the handle actuation, the bolt can also be driven in the bolt withdrawal direction by a tension or compression spring so that it requires only a displacement of the blocking lever 33 from the blocking position into a release position to withdraw the bolt 3 from a bolt forward motion position. In order to pre-lock the bolt, the crankshaft 35 , which engages in a recess of the bolt 3 , must be rotated. The blocking slot 30 configures an additional blocking step 34 . Before this blocking step 34 , the blocking extension 32 can lie in the relocked bolt position in order to block the bolt 3 against pre-locking.
An insertion shaft 4 for a coin 5 , flanked by shaft walls extending from the narrow end, is located on the narrow end of the housing 1 that points upward in the installed position. The surrounding edge of the insertion shaft 4 runs in an arc in the vicinity of the longitudinal sides of the insertion shaft 4 and configures a convexity 19 . Said convexity extends nearly as far as the narrow end of the housing. The convexity 19 is large enough so that a coin 5 inserted in the insertion shaft 4 can be held between two fingers in some areas.
The insertion shaft 4 is configured by two shaft walls 22 , 23 , so that a rear shaft wall 22 extends over the entire surface of the insertion shaft 4 . The front shaft wall 23 extends only over a portion of the width of the insertion shaft 4 and configures a coin insert limiting barrier 24 . The coin 5 is in a completely inserted position on this barrier 24 , which forms the base of the insertion shaft 4 . In this position a portion of the coin 5 lies inside the convexity 19 . The apex of the coin extending out of the housing 1 thus lies outside the imaginary insertion shaft edge.
A fixing jaw 8 is affixed to the shaft wall 22 . The fixing jaw 8 is affixed to the shaft wall 22 with screws in such a way that it can be displaced.
A stationary fixing jaw 7 is situated opposite the movable fixing jaw 8 perpendicular to the coin insertion direction. Both fixing jaws 7 , 8 are capable of partly surrounding the coin 5 in such a way that it is form-locked and thus ensured against withdrawal from the insertion shaft 4 . The coin 5 is thus locked inside a range that is less than 180 degrees.
The moveable fixing jaw 8 is connected to an oscillating lever 6 . Said oscillating lever 6 is T-shaped in configuration. The two arms of the T configure a bearing arm 10 or a guide groove 12 . The base of the T configures the aforementioned moveable fixing jaw 8 .
While the fixing jaw 8 is essentially situated parallel to the coin insertion direction and thus extends essentially perpendicular to the bearing arm 10 , the bearing arm 10 extends essentially parallel to the displacement direction of the bolt 3 . The bearing arm 10 is affixed to the housing or to the shaft wall 22 by means of a rotating axis 9 on its end facing away from the junction of the oscillating lever 6 .
An essentially square rib structure is located in the junction of the oscillating lever 6 . The ribs 13 , 14 , 15 , 16 , and 17 surround an essentially square vacant space that includes a rotation recess 11 , and a rotation stud 18 of the bolt 3 engages in said vacant space. The two sections of ribbing 13 , 14 that flank the rotation recess 11 configure blocking flanks. The rib structure continues in the displacement direction of the bolt 3 behind the rotation recess 11 and forms a guide groove 12 for the rotation stud 18 .
The rotation stud 18 is configured by a square section of the bolt 3 , which extends over the back side of the bolt 3 . A round stud extends beyond the front side of the bolt 3 on the corresponding spot. The rotation stud 18 is situated on the opposite side of the blocking slot 30 and is connected with an extension of the bolt 3 .
A blocking member 20 is positioned before the opening of the guide groove 12 in the housing 1 . Said member can be displaced with a needle-shaped tool 37 that is inserted into a housing opening 36 . It can be affixed rigidly in place with a screw that is not illustrated. The blocking element 20 comprises a blocking stud 21 , which can be inserted into the guide groove 12 in order to fix the oscillating lever 6 in a position in which the rotation recess 11 is situated in the path of movement of the rotation stud 18 . In this position, the bolt can be moved even when no coin 5 is inserted. If the blocking element 20 is not blocked in its blocking position by a screw or the like, then the rotation stud 18 , when the bolt 3 is completely pre-locked, can force the blocking stud 21 out of the guide groove 12 again.
The oscillating lever 6 is spring-powered by a tension or compression spring, not illustrated, in such a way that when no coin 5 is inserted the rotation stud 18 is situated in front of the upper blocking flank 13 . This corresponds to a rotation position of the oscillating lever 6 in which the moveable fixing jaw 8 assumes a position that is most closely situated to the stationary fixing jaw 7 . In this position the bolt 3 cannot be pre-closed because the rotation stud 18 cannot enter the rotation recess 11 , but instead runs into the blocking flank 13 when the bolt 3 is to be slid.
To be able to close the lock, a coin 5 must first be inserted into the insertion shaft 4 . The coin 5 here is completely inserted into the insertion shaft 4 until it is in contact with the base of the shaft 24 . In this position, a sufficiently large portion of the coin 5 still lies outside the insertion shaft 4 or inside the convexity 19 , so that the coin 5 can be withdrawn again from the insertion shaft 4 by gripping it with two fingers.
In the course of inserting the coin 5 into the insertion shaft 4 , the two fixing jaws 7 , 8 are first drawn apart from one another by moving the moveable fixing jaw 8 and then brought slightly closer together until the coin 5 is form-locked and so held in place by being partially surrounded. If the coin 5 has the correct diameter, then the rotation recess 11 is situated in the path of movement of the rotation stud 18 . With the blocking lever 33 released, the bolt 3 can be pre-closed by actuation of the handle 27 . In this process the rotation stud 18 descends through the rotation recess 11 and moves into the guide groove 12 that is flanked by two ribs. As soon as the rotation stud 18 has descended into the guide groove 12 , the oscillating lever 6 can no longer be rotated. The coin 5 is thus blocked in the insertion shaft 4 between the two fixing jaws 7 , 8 . The bolt 3 can be pre-locked until it is in its end position, in which the blocking extension 32 moves behind the blocking step 31 and can thus fix the bolt 3 in the front position. The bolt is withdrawn preferably by means of a tension spring, which is not shown, as described in DE 198 32 516 A1.
If a coin 5 with a smaller diameter is inserted into the insertion shaft 4 , then when the coin 5 is inserted the rotation stud 18 is situated in front of the blocking flank 13 . The sliding of the bolt is blocked. If a coin 5 with too great a diameter is inserted into the insertion shaft 4 , then when the coin is completely inserted the rotation stud 18 is situated in front of the lower blocking flank 14 . In this position as well, the bolt 3 cannot be displaced.
The fixing jaw 8 comprises an aperture for screwing in a screw. If a screw is screwed into this aperture, then the rotatability of the oscillating lever 6 is blocked. The screw-in aperture in the fixing jaw 8 is preferably flush with a threaded aperture in the shaft wall 23 . The threaded aperture is positioned in such a way that in the screwed-in position the oscillating lever assumes the position shown in FIG. 5 , in which the rotation stud 18 is situated in front of the rotation recess 11 , so that the bolt 3 can be pre-closed. With this type of permanently fixed oscillating lever 6 , the lock can be used as a container lock without deposit function.
In an embodiment that is not illustrated, the sensing device 7 , 8 comprises a sensor or a micro-switch. The sensor can be actuated by the oscillating lever. The sensor is preferably configured in such a way that it closes an electrical circuit if the oscillating lever assumes its rotation position shown in FIG. 5 , which corresponds to the rotation position with a correct coin 5 inserted. In all other rotation positions, that is with no coin inserted or with a coin that is too large or too small inserted, the electrical circuit is not closed. The displacement blocking of the bolt 3 is then exerted, preferably electromagnetically, for instance by the electro magnet 29 . Said electro magnet can move the blocking extension 32 into the release position only when the electrical circuit of the electric sensing device is closed. Alternatively, it is also possible that an otherwise closed electrical circuit is opened when a correct coin is inserted.
In an additional embodiment that is not shown, a switching vane of a scanner or of a switch immediately scans the coin and thus delivers an electrical scanning signal.
All disclosed characteristics are (in themselves) essential to the invention. The disclosure of the application hereby also includes the disclosure content of the related/added priority documents (copy of the pre-application) in its full content, also for the purpose of including characteristics of these documents in claims of the present invention.
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A container lock with a housing and, positioned in it, a bolt that can be displaced by actuating a handle, with an insertion shaft for inserting a coin, with a scanning device for scanning the diameter of the coin inserted into the insertion shaft as far as a scanning position, where the scanning device interacts with a blocking device in such a way that the bolt can be displaced only with a coin having a correct diameter. It is proposed that the scanning device should configure a fixing jaw, which securely grips the coin that is inserted in the insertion shaft so that it is partly accessible from outside in the scanning position with the bolt pre-locked to prevent its withdrawal.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to German Patent Application No. 10 2016 210 352.0, filed Jun. 10, 2016, the contents of such application being incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The invention relates to a position determination method in a vehicle as well as an electronic control module for carrying out such a method and an associated use.
BACKGROUND OF THE INVENTION
[0003] The process of determining the position of vehicles, in particular standard motor vehicles, by means of satellite navigation has been known for a long time. The accuracy which can be achieved in the process in terms of the position on the Earth's surface is now sufficient to provide the necessary data for most desired navigation purposes.
[0004] However, to date, the detection of the height of the vehicle has proven to be problematic. In this case, vertical positional inaccuracy can, for example, result in a false warning, if it is not recognized that the vehicle is located on a bridge over a road.
[0005] It is known that navigation systems, which are based on satellite navigation, can determine the height substantially less accurately than the horizontal position, which can in particular be expressed by, longitude and latitude. For example, the Galileo system has a horizontal positioning inaccuracy of 15 meters and a vertical positioning inaccuracy of 35 meters. Such positional inaccuracies are usually too large to be able to clearly assign a vehicle to a road if, for example, roads intersect bridges or tunnels.
[0006] incorporated by reference, and DE 196 45 394 A1, which is incorporated by reference. However, this requires the additional installation of a barometric altimeter, which results in an increased outlay and higher costs.
SUMMARY OF THE INVENTION
[0007] It is therefore an aspect of the invention to provide a position determination method which can be carried out as an alternative to and, in particular with less outlay compared to, embodiments in accordance with the prior art. In addition, it is an object of the invention to provide an associated electronic control module as well as an associated use.
[0008] An aspect of the invention relates to a position determination method in a vehicle, comprising the following steps:
receiving a signal from a pressure-based collision sensor of the vehicle, and establishing height information on the basis of the signal.
[0011] It has thereby been recognized within the framework of the invention that a separate barometric altimeter is not required to have air pressure-based height information available for position determination. Rather, collision sensors which can be used for this task are already installed in most vehicles. Such collision sensors are typically based on a volume which is pressurized or filled with a fluid, i.e. with a gas or a liquid, which is pressed in, in the event of a collision. A resulting change in pressure is detected by means of a pressure sensor. In the event that this pressure changes correspondingly quickly, it can be concluded that the vehicle has collided, for example with another vehicle, with a building or with a pedestrian.
[0012] Such collision sensors can now also be used to detect a change in air pressure, since a change in the air pressure also has an effect on the measured pressure, even if this takes place substantially more slowly than in the event of a collision. The slow change can be advantageously used to distinguish a collision from a height-related change in air pressure. If, for example, the vehicle is driving up an uphill gradient or down a downhill gradient, which frequently happens, for example, in city centers on entering tunnels, this can be simply recognized with the aid of the corresponding change in pressure. Such pressure changes take place over a considerably larger time scale than collisions, so that it is possible to distinguish between these without any problems.
[0013] A vehicle is, in particular, a standard motor vehicle which is operated on land. However, it can also be, for example, a watercraft or a muscle-powered vehicle as well. The use of the method in an aircraft is, in principle, also conceivable.
[0014] A side impact sensor and/or a pedestrian impact sensor is/are preferably used as the collision sensor(s). Side impact sensors are typically installed laterally in the vehicle, for example in side doors. Pedestrian impact sensors are typically installed in the front region, for example on the hood. Such sensors are typically configured in the manner described above and can therefore be preferably used for the purposes of the method according to the invention.
[0015] The height information is preferably a relative change in height. This makes it possible to detect vertical movements of the vehicle without a fixed reference point, which is easier to establish, as it is possible to dispense with a reference air pressure. Likewise it is, however, also possible to establish absolute height information, for example by using a reference air pressure. The reference air pressure can be obtained, for example, by using mobile data communication, for example from weather data.
[0016] The method preferably additionally comprises the following step:
determining a position of the vehicle.
[0018] This position can in particular include a position on the Earth's surface, i.e. longitude and latitude. It can be used for typical navigation purposes.
[0019] According to a preferred embodiment, the method additionally comprises the following step:
merging the position with the height information.
[0021] The position can therefore, for example, be enriched by the established height information for navigation purposes.
[0022] The method thereby preferably comprises the following step:
correcting or verifying a height as part of the position on the basis of the height information.
[0024] The height can, in this case, therefore be established, for example, both by means of satellite navigation and by means of barometric information, at least relatively in the latter case, and the corresponding information can be used in order to correct or verify the values. If, for example, the established changes in height point in different directions, this indicates a system error.
[0025] The position can be at least partially determined by means of satellite navigation. This corresponds to a simple and reliable method of determining the position.
[0026] The position can at least partially be determined by means of odometry. This makes it possible to determine the position on the basis of speed and course data or similar data of the vehicle.
[0027] The position can at least partially be determined by means of inertial sensors. In the process, actual accelerations can be detected and used.
[0028] The signal is preferably a raw signal, in particular without zero point correction. Such a raw signal can preferably be used for detecting pressure changes over a substantially longer time scale than in the event of collisions, since precisely such fluctuations are largely eliminated during the zero point correction which is otherwise used.
[0029] According to a preferred embodiment, the method is carried out in parallel with a plurality of signals. In this case, for example, signals from multiple collision sensors, for example from a pedestrian collision sensor and a side impact sensor or also multiple side impact sensors can be used, increasing the reliability when the method is carried out.
[0030] According to a preferred embodiment, the method additionally comprises the following steps:
determining a temperature, and establishing the height information as well on the basis of the temperature.
[0033] This can therefore take account of the fact that the signals from standard collision sensors are temperature-dependent, so that temperature compensation can increase the reliability and accuracy.
[0034] According to a further development, the method additionally comprises the following step:
determining a route of the vehicle and/or the risk of a collision on the basis of the height information. The risk of collision can, in this case, preferably also be established on the basis of height information of another vehicle. Such information can be exchanged, for example, by means of vehicle-to-X communication or other communication channels.
[0036] This further development makes it easy to recognize, for example in situations in which a vehicle is driving into a lower lying tunnel and another vehicle is passing through this tunnel at a somewhat higher level, that there is no risk of a collision. However, should the vehicles actually cross at the same level, the risk of a collision can be recognized. Such lower-lying tunnels occur in particular in city centers and can only be detected with difficulty with known navigation methods and, in particular, due to the fact that in such locations there is frequently only a restricted view up towards the sky, i.e. up towards satellites which provide position signals, because of the surrounding tall buildings.
[0037] In addition, an aspect of the invention relates to an electronic control module which is configured to carry out a method according to the invention. In addition, the invention relates to a non-volatile computer-readable storage medium on which program code is stored, during the execution of which a processor carries out a method according to the invention. In this case, it is possible to have recourse to all of the described embodiments and variants of the method.
[0038] In addition, an aspect of the invention relates to the use of a pressure-based collision sensor in order to establish height information of a vehicle. In particular, this can be effected in accordance with a method according to the invention. In the process, recourse can be had to all of the described embodiments and variants of the method.
[0039] In general, it should be mentioned that signals, in particular raw signals, can be obtained, for example from a pressure sensor such as a pressure satellite (pSAT), by means of which a change in air pressure can be determined. For example, this can be effected by means of the barometric height formula, by means of which a change in air pressure can be converted into a change in height. Alternatively, the change in air pressure can be determined by means of pressure sensors which are not fixed in the vehicle, which can therefore be installed, for example, in a smartphone or an electronic navigation device. These alternatives can also be linked.
[0040] The change in height signal can support the localization function in a sensor fusion with satellite navigation sensors, inertial sensors (IMU) and/or odometry sensors, for example as a measurement model in a Kalman filter, and thus provide the height information in a more accurate, more reliable and more secure manner as well as for longer and/or more quickly.
[0041] In particular, in the case of demanding satellite navigation (GNSS) conditions such as, for example, if the sky is largely concealed, i.e. in the event that few satellite signals can be received, the determination of position can be reduced to three (instead of the normal four) received GNSS satellites, in order to determine the horizontal position, while the vertical position is substantially supported by means of the change in pressure.
[0042] To this end, the height information can additionally or alternatively be supported, for example when using a tight coupling approach, by the barometric pressure sensor; alternatively, the system of equations of the GNSS calculation which has to be solved can be simplified in this regard by knowledge about the height component from the pressure sensor. It is not absolutely essential that four values are determined by means of more than four satellites (latitude, longitude, height and clock error) but, for example, just three values (latitude, longitude and clock error) would suffice, as a result of which three satellites would be enough for the calculation.
[0043] The present resolutions of 0.5 hPa per digit of typical collision sensors are sufficient for the procedure described here. In this case, the raw signal of the collision sensor is advantageously picked up, in order to analyze said raw signal. Since multiple collision sensors are, as a rule, installed in the vehicle, multiple signals can be redundantly used by collision sensors, in order to improve the safety and accuracy of the method. The height information from satellite information can be supported and/or filtered by means of a barometric sensor. A relative change in height can also be very easily detected, which is not typically possible by means of odometry and inertial sensor technology alone. It is also very easily possible to compare relative positions with each other in a certain environment, in order to recognize whether, for example, a broken down vehicle is at the same level and thus constitutes an obstacle, or whether it is located a few meters above the driver's own vehicle on a bridge and is therefore not critical. It is therefore very easily possible, even in the absence of an absolute height from the pressure sensor, to make a relative height statement, since the pressure conditions do not change so quickly within a limited period of time and location-related environment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The person skilled in the art will infer additional features and advantages from the embodiment example described below with reference to the attached drawing.
[0045] FIG. 1 shows a vehicle which is configured to carry out a method according to an aspect of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] FIG. 1 shows a vehicle 10 . The vehicle 10 comprises four wheels 20 , 22 , 24 , 26 . It is understood that said FIGURE is merely a schematic representation.
[0047] In addition, the vehicle 10 comprises a control module 30 which is configured to carry out a method according to the invention. In this respect, this is a control module according to the invention.
[0048] The vehicle 10 additionally comprises a pedestrian collision sensor 40 which is installed as shown in the front region of the vehicle 10 . Said pedestrian collision sensor 40 is constructed such that a pressurized volume is monitored by a pressure sensor, and this pressurized volume is installed along a section in the vehicle 10 , with which a pedestrian would normally collide in the event of a frontal impact with the vehicle 10 . The pedestrian collision sensor 40 can therefore conclude that a collision has occurred with a pedestrian in the event of a rapid change in pressure.
[0049] In addition, the vehicle 10 comprises a satellite navigation module 50 . Said satellite navigation module is configured to determine a position having a horizontal as well as a vertical component on the basis of satellite navigation signals.
[0050] Both the pedestrian collision sensor 40 and the satellite navigation module 50 are connected to the electronic control module 30 . The corresponding data are therefore constantly supplied to the electronic control module 30 .
[0051] The electronic control module 30 can compare a height of the vehicle 10 , which is recognized by the satellite navigation module 50 , with a pressure change over typical time scales of a change in vehicle height, which is detected by the pedestrian collision sensor 40 . Typically, a change in height recognized by the satellite navigation module 50 will be coarser than a corresponding change in pressure which is detected by the pedestrian collision sensor 40 . In this case, a relative change in height of the vehicle 10 can be calculated on the basis of the data which are provided by the pedestrian collision sensor 40 . This allows the electronic control module 30 , for example, to detect whether the vehicle 10 is driving into a lower-lying tunnel or whether it has taken a turn, which leads to an uphill or downhill gradient section. It is not possible to make such detections solely in many situations with the data supplied by the satellite navigation module 50 .
[0052] The risk of a collision with other vehicles can, in particular, be recognized by means of such provisions, for example when it depends on whether vehicles are located on the same level. Corresponding data can be exchanged with other vehicles by means of vehicle-to-X communication or other methods of communication.
[0053] Generally, it should be noted that vehicle to-X communication in particular denotes direct communication between vehicles and/or between vehicles and infrastructure installations. For example, this can therefore be vehicle-to-vehicle communication or vehicle-to-infrastructure communication. If, within the framework of this application, reference is made to communication between vehicles, this can, in principle, be effected, for example, within the framework of vehicle-to-vehicle communication, which is typically effected without switching by means of a mobile network or a similar external infrastructure and which therefore has to be delimited from other solutions which build, for example, on a mobile network. Vehicle-to-X communication can be effected, for example, using the standards IEEE 802.11p or IEEE 1609.4. Vehicle to-X communication can also be referred to as C2X communication. The subareas can be referred to as C2C (car-to-car) or C2I (car-to-infrastructure). However, the invention does not explicitly exclude vehicle-to-X communication with switching, for example, via a mobile network.
[0054] The indicated steps of the method according to the invention can be carried out in the sequence indicated. However, they can also be carried out in a different sequence. The method according to the invention can be carried out in one of its embodiments, for example with a specific set of steps, such that no additional steps are carried out. However, additional steps can in principle also be carried out, including those which are not mentioned.
[0055] The claims associated with the application do not constitute a \waiver of the attainment of more extensive protection.
[0056] If it emerges, during the course of the method, that a feature or a group of features is not absolutely necessary, a formulation of at least one independent claim is already striven for by the applicant now, which no longer comprises the feature or group of features. This can, for example, be a sub-combination of a claim which exists on the date of filing or a sub-combination of a feature which exists on the date of filing, which is restricted by additional features. Such claims or combinations of features, which are to be newly formulated, are to be deemed to also be covered by the disclosure of this application.
[0057] It is additionally pointed out that configurations, features and variants of the invention, which are described in the various embodiments or embodiment examples and/or which are shown in the FIGURES, can be combined with one another at will. Individual or multiple features can be freely interchanged. Resulting combinations of features are also to be understood to be covered by the disclosure of this application as well.
[0058] References in dependent claims are not to be understood to be a waiver of the attainment of independent protection of the subject matter for the features of the subordinate claims which refer back to the principal claims. These features can also be combined with other features at will.
[0059] Features which are merely disclosed in the description, or features which are only disclosed in the description or in a claim in conjunction with other features, can in principle be independently essential to the invention. They can therefore also be individually included in claims in order to demarcate the invention from the prior art.
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A position determination method in a vehicle, which uses signals from a pressure-based collision sensor. In addition, an associated electronic control module and an associated use.
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CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation of application Ser. No. 08/977,258, filed on Nov. 24, 1997, now U.S. Pat. No. 5,892,179, which is a continuation of application Ser. No. 08/416,619, filed on Apr. 5, 1995, now abandoned.
FIELD OF THE INVENTION
This invention relates to the field of microelectronic devices and more particularly to solder bumps for microelectronic devices.
BACKGROUND OF THE INVENTION
High performance microelectronic devices often use solder balls or solder bumps for electrical and mechanical interconnection to other microelectronic devices. For example, a very large scale integration (VLSI) chip may be electrically connected to a circuit board or other next level packaging substrate using solder balls or solder bumps. This connection technology is also referred to as “Controlled Collapse Chip Connection—C4” or “flip-chip” technology, and will be referred to herein as “solder bumps”.
A significant advance in this technology is disclosed in U.S. Pat. No. 5,162,257 to Yung entitled “Solder Bump Fabrication Method” and assigned to the assignee of the present invention. In this patent, an under bump metallurgy is formed on the microelectronic substrate including contact pads, and solder bumps are formed on the under bump metallurgy opposite the contact pads. The under bump metallurgy between the solder bumps and the contact pads is converted to an intermetallic which is resistant to etchants used to etch the under bump metallurgy between solder bumps. Accordingly, the base of the solder bumps is preserved.
In many circumstances, it may be desired to provide a solder bump on the substrate at a location remote from the contact pad and also form an electrical connection between the contact pad and the solder bump. For example, a microelectronic substrate may be initially designed for wire bonding with the contact pads arranged around the outer edge of the substrate. At a later time it may be desired to use the microelectronic substrate in an application requiring solder bumps to be placed in the interior of the substrate. In order to achieve the placement of a solder bump on the interior of the substrate away from the respective contact pad, an interconnection or redistribution routing conductor may be necessary.
U.S. Pat. No. 5,327,013 to Moore et al. entitled “Solder Bumping of Integrated Circuit Die” discloses a method for forming a redistribution routing conductor and solder bump on an integrated circuit die. This method includes forming a terminal of an electrically conductive, solder-wettable composite material. The terminal includes a bond pad overlying the passivation layer remote from a metal contact and a runner that extends from the pad to the metal contact. A body of solder is reflowed onto the bond pad to form a bump bonded to the pad and electrically coupled through the runner.
In this method, however, the solder bump is formed by pressing a microsphere of a solder alloy onto the bond pad. In addition, the spread of solder along the runner during reflow is limited. In the illustrated embodiment, a solder stop formed of a polymeric solder resist material is applied to the runner to confine the solder to the bond pad.
Notwithstanding the above mentioned references, there continues to exist a need in the art for methods of producing redistribution routing conductors and solder bumps efficiently and at a reduced cost.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved method of forming a redistribution routing conductor.
It is another object of the present invention to provide a method of forming a redistribution routing conductor which can be integrally formed together with an associated solder bump.
These and other objects are provided, according to the present invention, by forming an under bump metallurgy layer on the microelectronic substrate and forming a solder structure including an elongate portion and an enlarged width portion on the under bump metallurgy layer. The solder structure can be formed by electroplating on the desired portions of the under bump metallurgy layer which are defined by a mask. The excess portions of under bump metallurgy not covered by solder can then be selectively removed using the solder structure as a mask. Accordingly, a single masking step can be used to define both the solder structure and the under bump metallurgy layer.
The solder can then be made to flow. Unexpectedly, the surface tension within the solder will cause the flowing solder to form a thin solder layer on the elongate portion of the under bump metallurgy layer and a raised solder bump on the enlarged width portion of the under bump metallurgy layer. Accordingly, a single solder deposition step followed by a solder flow step (typically induced by heat) can be used to form a solder structure including both a thin elongate portion and a raised enlarged width portion.
In one embodiment, the present invention includes a method of forming a redistribution routing conductor on a microelectronic substrate including an electrical contact pad at a surface of the microelectronic substrate. This method includes the steps of forming an under bump metallurgy layer on the surface, and forming a solder structure on the under bump metallurgy layer opposite the microelectronic substrate. The under bump metallurgy layer electrically contacts the electrical contact pad, and the solder structure includes an elongate portion and an enlarged width portion.
The step of forming a solder structure preferably includes the step of forming a solder structure including an elongate portion which extends over the electrical contact pad. This solder structure may define first (exposed) and second (unexposed) portions of the under bump metallurgy layer, and the step of forming a solder structure may be followed by the step of selectively removing the first (exposed) portion of the under bump metallurgy layer which is not covered by the solder structure. Accordingly, the solder structure can be used as a masking layer to selectively remove the first portion of the under bump metallurgy layer not covered by solder after forming the solder structure, thereby eliminating the need for separate photolithography steps to pattern the solder structure and the under bump metallurgy layer.
The elongate solder portion preferably has one end that is positioned on the under bump metallurgy layer opposite the contact pad and a second end that is connected to the enlarged width portion. Accordingly, the solder structure defines respective elongate and enlarged width portions of the under bump metallurgy layers, and one end of the elongate portion of the under bump metallurgy layer preferably makes electrical contact with the contact pad. It will be understood that other elongate solder portions may extend across the under bump metallurgy layer in other directions from the point opposite the contact pad, and also that the elongate portion may extend slightly beyond the point opposite the contact pad.
This method may also include the step of causing the solder in the solder structure to flow from the elongate portion to the enlarged width portion. Accordingly, a raised solder bump may be formed in the enlarged width portion of the solder structure and a thin solder layer may be formed in the elongate portion of the solder structure. This step is preferably accomplished by heating the solder above its liquidus temperature and confining it to the elongate and enlarged width portions of the under bump metallurgy layer so that surface tension induced internal pressures cause the solder to flow to the enlarged width portions. The flowing solder may be confined by forming a solder dam layer on the first (exposed) portion of the under bump metallurgy layer which is not covered by the solder structure.
The step of causing the solder structure to flow may form an intermetallic region between the under bump metallurgy layer and the solder structure. This intermetallic region includes a constituent of the metallurgy layer and a constituent of the solder structure. This intermetallic region is resistant to etchants used to remove the first (exposed) portion of the under bump metallurgy layer thereby reducing undercutting of the solder structure.
The step of forming the under bump metallurgy layer preferably includes the steps of forming a chromium layer on the microelectronic substrate, forming a phased layer of chromium and copper on the chromium layer, and forming a copper layer on the phased layer opposite the chromium layer. This structure provides an electrically conductive base that will adhere to the microelectronic substrate and contact pad as well as the solder structure. The step of forming the under bump metallurgy layer may also include the step of forming a titanium layer between the microelectronic substrate and the chromium layer.
The step of forming the solder structure may include the steps of forming a patterned mask layer on the under bump metallurgy layer, forming the solder structure on the second portion of the under bump metallurgy layer, and selectively removing the patterned mask layer. The patterned mask layer preferably covers the first portion of the under bump metallurgy layer and defines the second portion of the under bump metallurgy layer on which the solder structure is formed.
In addition, the step of forming the solder structure includes the step of electroplating solder on the second portion of the under bump metallurgy layer. By forming an under bump metallurgy layer that extends across the microelectronic substrate, the under bump metallurgy layer can be used as an electroplating electrode for a plurality of solder structures. Accordingly, a plurality of solder structures can be formed in a single electroplating step with each solder structure having a common uniform height.
The present invention also includes a solder bump structure on a microelectronic substrate including an electrical contact having an exposed portion. This solder bump structure includes an under bump metallurgy structure on the microelectronic substrate, and a solder structure on the under bump metallurgy structure opposite the microelectronic substrate. The metallurgy structure includes an elongate portion having a first end which electrically contacts the exposed portion of the electrical contact and an enlarged width portion connected to a second end of the elongate portion. The solder structure includes an elongate portion on the metallurgy structure and an enlarged width portion on the enlarged width portion of the metallurgy structure. Accordingly, the enlarged width portion of the solder structure can be formed on a portion of the microelectronic substrate other than the contact pad and still be electrically connected to the pad.
The elongate portion of the solder structure may have a first predetermined thickness and the enlarged width portion of the solder structure may have a second predetermined thickness. The first predetermined thickness is preferably thin relative to the second predetermined thickness. Accordingly, the enlarged width portion of the solder structure preferably forms a raised solder bump which can be used to connect the microelectronic substrate, both electrically and mechanically, to a printed circuit board or other next level packaging substrate. Alternately, the elongate portion of the solder structure and the enlarged width portion of the solder structure may have a common predetermined thickness.
The solder bump structure may also include an intermetallic region between the under bump metallurgy structure and the solder structure, and this intermetallic region includes a constituent of the metallurgy structure and a constituent of the solder structure.
Alternately, a solder bump structure may include an under bump metallurgy layer on the microelectronic substrate and electrically contacting the exposed portion of the electrical contact. This solder bump structure also includes a solder structure on the under bump metallurgy layer opposite the microelectronic substrate. The solder structure includes an elongate portion having a first end opposite the exposed portion of the electrical contact and an enlarged width portion connected to a second end of the elongate portion. This under bump metallurgy layer may extend across the microelectronic substrate with the solder structure defining first (exposed) and second (unexposed) portions of the under bump metallurgy layer. This continuous under bump metallurgy layer may be used as an electrode for electroplating.
In addition, the structure may include a solder dam on the first (exposed) portions of the under bump metallurgy layer. This solder dam may be used to contain the solder during a solder flow step as discussed above.
Accordingly, an under bump metallurgy layer can be formed on a microelectronic substrate and used as an electrode to electroplate a solder structure including an elongate portion and an enlarged width portion. The solder structure is then used as a mask to selectively remove the portions of the under bump metallurgy layer not covered by the solder structure. A single photolithography step can therefore be used to pattern both the solder structure and the under bump metallurgy layer. In addition, the solder can be caused to flow from the elongate portion of the solder structure to the enlarged width portion thereby forming a raised solder bump. This is preferably achieved by heating the solder above its liquidus temperature allowing surface tension induced internal pressures to affect the flow. Accordingly, a stable multi-level solder structure is produced.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1-5 are cross sectional side views of a microelectronic substrate at various stages during the manufacture of a redistribution routing conductor according to the present invention.
FIGS. 6-10 are top views of a microelectronic substrate at various stages during the manufacture of a redistribution routing conductor corresponding respectively to FIGS. 1 - 5 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thickness of layers and regions are exaggerated for clarity. Like numbers refer to like elements throughout.
The invention relates to a microelectronic structure 11 including a redistribution routing conductor and a raised solder bump, as shown from the side in FIG. 5 and as shown from the top in corresponding FIG. 10 . The microelectronic structure includes a contact pad 14 and passivation layer 12 on a substrate 15 . The redistribution routing conductor 17 and solder bump 21 each include respective portions of under bump metallurgy layer 16 A-B and solder layer 22 A-B.
The redistribution routing conductor 17 includes a relatively elongate solder portion 22 B on a respective elongate under bump metallurgy portion 16 B. The solder bump 21 includes an enlarged width solder portion 22 A on a respective enlarged width under bump metallurgy portion 16 A. Preferably the elongate solder portion 22 B is relatively thin while the enlarged width solder portion 22 A is raised, as shown in FIG. 5 .
Accordingly, the solder bump 21 can be located at a point on the substrate relatively distant from the contact pad 14 with the redistribution routing conductor 17 providing an electrical connection therebetween. This arrangement provides the advantage that a substrate having a layout with a contact pad 14 at one predetermined location can have an associated solder bump at a second location. This can be particularly useful, for example, when a substrate has a layout with contact pads arranged for wire bonding, and it is desired to use the substrate in a flip-chip application. This solder bump and redistribution routing conductor can be fabricated simultaneously, as described below with regard to FIGS. 1-10.
While the redistribution routing conductor 17 can be straight as shown, it may also include bends and curves. Furthermore, the solder bump 21 may be circular as shown or it can have other shapes such as rectangular.
The solder bump 21 and the redistribution routing conductor 17 are preferably formed simultaneously. FIGS. 1-5 are cross-sectional side views of microelectronic structures at various stages of fabrication, while FIGS. 6-10 are corresponding top views of the same microelectronic structures. The microelectronic structure 11 initially includes a passivation layer 12 and an exposed contact pad 14 on a substrate 15 , as shown in FIGS. 1 and 6.
The substrate 15 can include a layer of a semiconducting material such as silicon, gallium arsenide, silicon carbide, diamond, or other substrate materials known to those having skill in the art. This layer of semiconducting material can in turn include one or more electronic devices such as transistors, resistors, capacitors, and/or inductors. The contact pad 14 may comprise aluminum, copper, titanium, an intermetallic including combinations of the aforementioned metals such as AlCu and AlTi 3 , or other materials known to those having skill in the art. This contact is preferably connected to an electronic device 19 in the substrate.
The passivation layer 12 can include polyimide, silicon dioxide, silicon nitride, or other passivation materials known to those having skill in the art. As shown, the passivation layer 12 may cover top edge portions of the contact pad 14 opposite the substrate 15 , leaving the central portion of the contact pad 14 exposed. As will be understood by those having skill in the art, the term substrate may be defined so as to include the passivation layer 12 and contact pad 14 of FIGS. 1 and 6.
An under bump metallurgy layer 16 is formed on the passivation layer to provide a connection between the solder bump and the contact pad 14 and to provide a plating electrode, as shown in FIGS. 2 and 7. The under bump metallurgy layer 16 also protects the contact pad 14 and passivation layer 12 during subsequent processing steps, and provides a surface to which the solder will adhere. The under bump metallurgy layer preferably includes a chromium layer on the passivation layer 12 and contact pad 14 ; a phased chromium/copper layer on the chromium layer; and a copper layer on the phased layer. This structure adheres to and protects the passivation layer 12 and contact pad 14 , and also provides a base for the plated solder which follows.
The under bump metallurgy layer may also include a titanium barrier layer between the substrate and the chromium layer as disclosed in U.S. patent application entitled “Solder Bump Fabrication Methods and Structures Including a Titanium Barrier Layer” filed Mar. 20, 1995 and assigned to the assignee of the present invention. This titanium barrier layer protects the passivation layer from etchants used to remove the other components of the under bump metallurgy layer and also prevents the formation of residues on the passivation layer which may lead to shorts between solder bumps and redistribution routing conductors. The titanium layer can be easily removed from the passivation layer without leaving significant residues.
Various under bump metallurgy layers are disclosed, for example, in U.S. Pat. No. 4,950,623 to Dishon entitled “Method of Building Solder Bumps”, U.S. Pat. No. 5,162,257 to Yung entitled “Solder Bump Fabrication Method”, and U.S. patent application to Mis et al. entitled “Solder Bump Fabrication Methods and Structures Including a Titanium Barrier Layer” filed on Mar. 20, 1995. Each of these references is assigned to the assignee of the present invention, and the disclosure of each is hereby incorporated in its entirety herein by reference.
A solder dam 18 can be formed on the under bump metallurgy layer 16 . This solder dam 18 preferably includes a layer of a solder non-wettable material such as titanium or chromium on the under bump metallurgy layer 16 . The solder dam 18 will be used to contain the solder if a reflow step is performed prior to removing the first (exposed) portion of the under bump metallurgy layer 16 not covered by solder, as discussed below. A mask layer 20 is then formed on the solder dam 18 . The mask layer may comprise a photoresist mask or other mask known to those having skill in the art.
The mask layer 20 is patterned to cover the solder dam over the first portion of the under bump metallurgy layer and to uncover areas of the solder dam 18 over a second portion of the under bump metallurgy layer 16 on which the solder bump and redistribution routing conductor will be formed. The uncovered portion of the solder dam is then removed thereby uncovering the second portion of under bump metallurgy layer 16 , as shown in FIGS. 3 and 8. More particularly, the second portion of the under bump metallurgy layer 16 , which is not covered by the solder dam and patterned mask layer, includes an enlarged width portion 16 A and an elongate portion 16 B.
A solder layer 22 is preferably electroplated on the second portion of the under bump metallurgy layer 16 , as shown in FIGS. 4 and 9. The solder can be electroplated by applying an electrical bias to the continuous under bump metallurgy layer 16 and immersing the microelectronic structure in a solution including lead and tin, as will be understood by those having skill in the art. This electroplating process allows solder layers to be formed simultaneously on a plurality of second portions of the under bump metallurgy layer 16 . The solder will not plate on the mask layer 20 . Alternatively, the solder can be applied by screen printing as a paste, by evaporation, by e-beam deposition, by electroless deposition or by other methods known to those having skill in the art. In addition, while lead-tin solder is used for purposes of illustration throughout the specification, other solders such as gold solder, lead-indium solder, or tin solder can be used as will be understood by those having skill in the art.
The solder layer 22 includes an elongate portion 22 B and an enlarged width portion 22 A. After removing the mask layer 20 , the microelectronic structure 11 can be heated causing the solder to flow from the elongate solder portion 22 B to the enlarged width solder portion 22 A thereby forming a raised solder bump at the enlarged width solder portion 22 A. The solder dam 18 prevents the solder from spreading beyond the elongate 16 B and enlarged width 16 A portions of the under bump metallurgy layer 16 , as shown in FIGS. 5 and 10.
The solder will flow when heated above its liquidus temperature (approximately 299° C. for solder having 90% lead and 10% tin), and this process is commonly referred to as solder reflow. During reflow, the surface tension of the solder creates a relatively low internal pressure in the enlarged width solder portion 22 A over the relatively wide geometry provided for the solder bump, and a relatively high internal pressure in the elongate solder portion 22 B over the relatively narrow geometry provided for the redistribution routing conductor.
In order to equalize this internal pressure differential, solder flows from the elongate solder portion 22 B to the enlarged width solder portion 22 A. Accordingly, the solder forms a raised solder bump at the enlarged width solder portion 22 A and a relatively thin layer of solder at the elongate solder portion 22 B over the redistribution routing conductor. When the solder is cooled below its liquidus temperature, it solidifies maintaining its shape including the raised solder bump and the thin layer of solder over the redistribution routing conductor.
It is known in the art of printed circuit board manufacture to apply solder at a uniform level on PCB lands by screen printing, and that the level of solder can be increased locally by enlarging a part of the land. See, Swanson, “PCB Assembly: Assembly Technology in China, ” Electronic Packaging & Production , pp. 40, 42, January 1995. To their knowledge, however, Applicants are the first to realize that solder can be electroplated on a microelectronic substrate at a uniform level and then heated to produce a raised solder bump together with a redistribution routing conductor on the substrate.
Furthermore, U.S. Pat. No. 5,327,013 to Moore et al. states that a microsphere of a solder alloy can be pressed onto a pad, and that a stop formed of a polymeric solder resist material can be applied to the runner to confine the solder to the bond pad. While this patent states that the spread of solder along the runner during reflow can be limited by constricting the width of the runner section relative to the bond pad, there is no suggestion that the relative dimensions of the runner section and the bond pad can be used to cause solder to flow from the runner to the bond pad thereby forming a multilevel solder structure. In addition, neither of these references suggest that a solder structure having an elongate portion and an enlarged width portion can be used to mask the under bump metallurgy layer in order to form a redistribution routing conductor together with a raised solder bump using only a single masking step.
The method of the present invention relies on differences in the surface-tension induced internal pressure of the reflowed (liquid) solder to form a thin layer of solder at the elongate solder portion 22 B and a raised solder bump at the enlarged width solder portion 22 A. The internal pressure P of a liquid drop of solder can be determined according to the formula:
P= 2 T/r,
where T is the surface tension of the liquid solder, and r is the radius of the drop.
Where liquid solder is on a flat wettable surface such as the under bump metallurgy layer, the formula becomes:
P= 2 T/r′.
In this formula, r′ is the apparent radius of the liquid solder, and the apparent radius is the radius of the of the arc (radius of curvature) defined by the exposed surface of the solder. The apparent radius is dependent on the width of the underlying solder wettable layer such as the second portion of the under bump metallurgy layer which is in contact with the solder. Accordingly, the internal pressure of a reflowed solder structure is inversely proportional to the width of the second portion of the under bump metallurgy in contact with the solder. Stated in other words, a solder portion having on a relatively wide under bump metallurgy portion will have a relatively low internal pressure while a solder portion on an elongate (relative narrow) under bump metallurgy portion will have a relatively high internal pressure. The internal pressures will equalize when the apparent radii of the elongate solder portion 22 B and the enlarged width solder portion 22 A are approximately equal.
Accordingly, when the solder layer 22 with a uniform level illustrated in FIGS. 4 and 9 is heated above its liquidus temperature, solder flows from the elongate solder portion 22 B to the enlarged width solder portion 22 A until each portion has approximately the same apparent radius thereby forming a raised solder bump. If the solder flow step is performed prior to removing the first portion of the under bump metallurgy layer 16 not covered by the solder structure (comprised of solder portions 22 A-B), an intermetallic can be formed between the solder portions 22 A-B and under bump metallurgy portions 16 A-B adjacent the solder wherein the intermetallic is resistant to etchants commonly used to remove the under bump metallurgy. Accordingly, this intermetallic reduces undercutting of the solder during the following step of removing the first portion of the under bump metallurgy not covered by solder, as discussed in U.S. Pat. No. 5,162,257 to Yung entitled “Solder Bump Fabrication Method” and assigned to the assignee of the present invention.
Preferably, the under bump metallurgy layer 16 includes a copper layer adjacent the solder structure and the solder is a lead-tin solder. Accordingly, the step of causing the solder to flow will cause the solder to react with the copper to form an intermetallic region adjacent the solder structure, and this intermetallic will comprise Cu 3 Sn. This intermetallic does not readily react with etchants commonly used to remove under bump metallurgy layers thereby reducing undercutting of the solder structure.
The solder layer 22 is then preferably used as a mask to selectively etch the first portions of the solder dam 18 and under bump metallurgy 16 not covered by solder. A chemical etchant can be used which etches the under bump metallurgy layer 16 preferentially with respect to the solder portions 22 A-B. Accordingly, no additional masking step is required to pattern the under bump metallurgy layer. Stated in other words, the formation of mask layer 20 is the only masking step required to pattern the solder dam 18 (FIGS. 3 and 8 ), selectively expose the second portion of the under bump metallurgy layer 16 during the plating step (FIGS. 3 and 8 ), and remove the first portions of the under bump metallurgy layer not covered by solder after the plating step (FIGS. 5 and 10 ).
Alternately, the first portions of the under bump metallurgy layer 16 not covered by solder portions 22 A and 22 B can be selectively removed prior to causing the solder to flow. In this case, the elongate 22 B and enlarged width 22 A solder portions are respectively supported on only the elongate 16 B and enlarged width 16 A under bump metallurgy portions, and while the liquid solder is wettable to the under bump metallurgy, it is not wettable to the passivation layer 12 . Accordingly, the passivation layer can contain the solder during the solder flow step, and the solder dam 18 can be eliminated.
In another alternative, the solder dam can include a solder non-wettable layer on the under bump metallurgy layer 16 and a solder wettable layer, such as copper, on the solder non-wettable layer opposite the under bump metallurgy layer, as disclosed in U.S. patent application to Mis et al. entitled “Solder Bump Fabrication Methods and Structures Including a Titanium Barrier Layer” filed Mar. 20, 1995, and assigned to the assignee of the present invention. The solder wettable layer allows solder to be plated on portions of the solder dam as well as the second portion of the under bump metallurgy layer not covered by the solder dam or mask.
Accordingly, the mask layer 20 can uncover portions of the solder dam as well as portions of the under bump metallurgy layer 16 thereby allowing a greater volume of solder to be plated. The mask layer 20 and underlying portions of the solder wettable layer are then removed. When heat is applied to cause the solder to flow, the remaining portion of the solder wettable layer under the solder will be dissolved into the solder exposing the solder to the solder non-wettable layer. Accordingly, the solder will retreat to the second portion of the under bump metallurgy layer which is wettable.
As an example, a first portion of the under bump metallurgy layer 16 is covered by a solder dam 18 and a mask layer 20 . A second portion of the under bump metallurgy layer 16 is uncovered and has an elongate portion 16 B that is 150 μm wide and 500 μm long, and a circular enlarged width portion 16 A with a 500 μm diameter (or width), as shown in FIGS. 3 and 8. A uniform 35 μm high solder layer 22 is then electroplated on the second portion of the under bump metallurgy layer 16 including elongate portion 16 A and enlarged width portion 16 B, as shown in FIG. 4 . This solder is 90% lead and 10% tin. After removing the mask layer 20 , the solder is heated above its liquidus temperature (approximately 299° C.) allowing it to flow.
The liquid solder is contained on the second portion 16 A-B of the solder wettable under bump metallurgy layer by the solder dam 18 to which the solder will not wet. Because the solder structure has varying widths, the internal pressure of the solder structure is not consistent when the height is uniform. In particular, the internal pressure of the elongate solder portion 22 B is relatively high (approximately 1.283×10 4 Pa or 1.86 psi) and the internal pressure of the enlarged width solder portion 22 A is relatively low (approximately 3.848×10 3 Pa or 0.558 psi) at the original solder height.
Accordingly, solder flows from the elongate solder portion 22 B to the enlarged width solder portion 22 A until the internal pressures equalize, thereby forming a raised solder bump at the enlarged width solder portion 22 A, as shown in FIGS. 5 and 10. In FIGS. 5 and 10, the solder dam 18 and the first portion of the under bump metallurgy layer 16 not covered by the solder structure have also been removed.
In this example, equilibrium is obtained at an internal pressure of approximately 3.4×10 3 Pa (0.493 psi). At equilibrium, the elongate solder portion 22 B is approximately 10 μm high and the enlarged width solder portion is approximately 130 μm high, and both portions have a radius of curvature of approximately 281 μm. Accordingly, a two level solder structure can be provided with a single masking step. When cooled, this structure solidifies while maintaining its form. In addition, the elongate solder portion 22 B with a solder height of 10 μm is sufficient to mask the respective elongate under bump metallurgy layer portion 16 B when removing the first portion of the under bump metallurgy layer not covered by solder. The enlarged width portion of the solder structure may have a width (or diameter if the enlarged width portion is circular) of at least 2 times a width of the elongate portion of the solder structure in order to ensure that the solder bump formed by the method described above is sufficiently raised relative to the elongate solder portion to provide an adequate connection to a printed circuit board.
In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.
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A flip-ship structure having a semiconductor substrate including an electronic device formed thereon, a contact pad on said semiconductor substrate electrically connected to said electronic device, a passivation layer on said semiconductor substrate and on said contact pad wherein said passivation layer defines a contact hole therein exposing a portion of said contact pad, an under-bump metallurgy structure on said passivation layer electrically contacting said portion of said contact pad that is exposed; and a solder structure on said under-bump metallurgy structure opposite said semiconductor substrate, said solder structure including an elongate portion on said elongate portion of said metallurgy structure opposite said contact pad and an enlarged width portion on said enlarged width portion of said metallurgy structure opposite said passivation layer.
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This is a continuation of application Ser. No. 587,466, filed Mar. 8, 1984, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to semiconductor devices and the manufacture thereof and, in particular, to semiconductor processing employing silicides.
Polysilicon has conventionally been employed for gates and interconnections in integrated circuits. However, for small geometry, high speed integrated circuits it is desirable to use alternative materials with lower resistivity, such as silicide materials. The resistivity of polysilicon is high (1000 μΩcm) and roughly fifty times larger than some silicides, for example titanium disilicide has a resistivity of 20 μΩcm, and thus interconnections of polysilicon are extremely resistive in fine-line circuits. The propagational delay of electrical signals in such interconnect lines is a function of the product of the lumped capacitance and resistance of the interconnect line. As devices sizes are scaled down to achieve higher packing densities and speeds, this delay becomes dominated by the resistive component and thus new materials must be used. Silicides comprise such alternative materials which can be entirely compatible with the other components of the manufacturing process. Provided that the introduction of the material does not significantly perturb the existing process, the advantage of the new material can also be exploited in present day technologies.
A process has been developed whereby the silicide is formed by interdiffusing a layer of metal (tungsten, molybdenum, titanium, tantalum, etc.) with a sheet of doped polysilicon used to form the conventional gate and interconnects. This heterogeneous layer is then etched to form the gate and interconnects of the device. However, because the silicide overlying the doped polysilicon etches at different rates from the polysilicon, some undesirable undercutting at the gate occurs.
An alternative process has been developed to silicide the gate and diffused regions, however this is a complex process.
The undercutting problems of the first mentioned process and the complexity of the second represent considerable barriers to the implementation of silicide into an existing process.
BRIEF SUMMARY OF THE INVENTION
According to the present invention there is provided a method of manufacturing semiconductor devices including the steps of defining at least one polysilicon element on an oxidised surface of a silicon substrate, metallising the at least one defined polysilicon element, including sidewalls thereof, and causing the interdiffusion of the metal and the polysilicon whereby to form a metallic silicide layer extending over the at least one defined polysilicon element and up to the said oxidised surface on which the at least one defined polysilicon element is disposed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a to c represent in schematic cross-section successive stages in the first-mentioned known process,
FIGS. 2a to c represent in schematic cross-section successive stages in the second-mentioned known process, and
FIGS. 3a to c represent in schematic cross-section successive stages, in a method according to the present invention.
DETAILED DESCRIPTION
The known process shown in FIGS. 1a to c comprises the following steps. On a silicon substrate 1, an oxide layer 2, which is thin in the area where source, drain and gate regions of the device are to be formed, is provided by conventional means. A layer of doped polycrystalline silicon (polysilicon) 3 is provided over the oxide 2 (FIG. 1a). A metal layer 4 (FIG. 1b) of, for example, tungsten, molybdenum, titanium or tantalum, is deposited on the polysilicon layer 3. A metallic silicide layer (FIG. 1c) is formed by interdiffusing layers 3 and 4. The structure is then etched to form the gate 6 of the device and interconnects (not shown) and, because the silicide 5 etches at a different rate from the doped polysilicon 3, undercutting as at 7 occurs. The source 8 and drain 9 regions are next defined and implanted or diffused, and the process continues with the conventional oxidation step (intermediate oxide) (not shown), the oxidation at the silicide layer of the gate 6 relying on the diffusion of silicon from the underlying polysilicon to feed the oxidation process. The commercial process which employs this procedure is termed the POLYCIDE process. Adoption of the POLYCIDE process results in few changes when compared with the conventional polysilicon process, except that it introduces difficulties in etching the heterogeneous structure.
In the other known process illustrated in FIGS. 2a to c and termed the SALICIDE process, the gate, interconnect, and diffused regions are silicided. In this process a polysilicon gate 10 is defined conventionally upon oxide layer 2 on substrate 1. A layer of CVD (chemical vapour deposited) oxide is deposited over the gate 10 and interconnects (not shown) and this oxide is etched anisotropically to leave side wall spacers 11 of oxide adjacent the gate 10. This etching serves also to open windows 12, via which the source and drain regions 8 and 9 are formed conventionally, and to remove any oxide in the contact areas and on the polysilicon 10. A layer of metal, for example titanium, tantalum etc., is then deposited over the substrate surface and metallic silicide 13 formed by interdiffusing in a furnace the metal of the layer and the silicon. Only in the areas of exposed silicon can the silicide form and no change occurs where the metal is deposited over oxide. The residual (unreacted) metal is then etched away preferentially to leave the silicide 13 in the diffused, and gate interconnect areas as illustrated in FIG. 2c, together with other interconnect areas, not shown. This method is called SALICIDE (self-aligned silicide), the silicide being self-aligned to the exposed silicon. Processing continues with the conventional oxidation step etc. The oxide sidewall spacers 11 introduce complexities with regard to processing, but they are essential to avoid gate to source/drain short circuits.
An embodiment of the present invention is illustrated in FIGS. 3a to c. FIG. 3a shows a silicon substrate 20 in which source and drain regions 21 and 22 have been provided by suitable processing, for example selective diffusion or implantation. An oxide layer 23 extends over the entire surface of the substrate 20 and as illustrated is thinner in the source, drain and gate region due to the processing involved. A layer of doped polycrystalline silicon (polysilicon) is provided over the oxide 23 and etched to define a polysilicon gate 24 aligned with the source and drain regions 21 and 22, together with interconnects (not shown). A layer of metal 25 (FIG. 3b), for example, titanium, tungsten, tantalum, molybdenum etc., is then deposited over the polysilicon gate 24, interconnects and the exposed oxide 23. During a subsequent annealing process the metal overlying the polysilicon gate 24 and polysilicon interconnects becomes interdiffused therewith to form a metallic silicide, whereas there is no reaction between the metal and any directly underlying oxide. The residual (unreacted) metal is etched away to leave a metallic silicide 26 (FIG. 3c) over the gate 24 and around its sidewalls and similarly over and around the interconnects. Processing continues with the conventional intermediate oxidation using the underlying polysilicon as a source of silicon to feed the oxidation process at the gate. The etchant employed to define the polysilicon gate 24 and interconnects must be sufficiently selective to leave the oxide 23 over the diffused regions 21 and 22, otherwise silicides would form in these regions leading to gate to source/drain short circuits.
A suitable annealing process is a transient (pulse) process which comprises raising the temperature of the thus processed silicon substrate to 800° C. within 10 seconds and then allowing it to cool naturally. This annealing is performed in a chamber which is purged by nitrogen and the oxygen and water concentrations should not exceed 2 rpm. Such annealing may be performed using a commercial halogen lamp annealing equipment such as "Heatpulse" as supplied by A.G. Associates of Palo Alto, Calif., United States of America.
In the case of titanium we have found that it is necessary to interdiffuse the titanium and polysilicon using such a pulse annealing technique since titanium has such a strong affinity for oxygen and normal furnace annealing results in oxidation of the metal before the silicide is formed. Even with use of an inert gas (nitrogen) in a normal furnace, air trapped between wafers during loading in the furnace and contamination of the inert gas with small quantities of oxygen and water leads to significant oxidation.
Our United Kingdom patent application No. 8203242 (Ser. No. 2114809) relates to the formation of silicides from titanium and silicon which are deposited as a plurality of alternate layers, or are co-sputtered, and are pulse annealed. The present application, however, is concerned with a process for forming a silicide layer, by interdiffusing a single separate metallic layer, preferably titanium, overlying a defined polysilicon element, which can be readily implemented into an existing manufacturing process.
The proposed process is similar to the POLYCIDE process but differs therefrom in that the gate and interconnects are defined before the metal deposition step and in that no undercutting results. The proposed process can be implemented with conventional processing technology and does not disturb the overall conventional polysilicon process significantly, whilst resulting in low interconnect resitance values and retaining the oxidisability of the resulting silicide composite.
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Polysilicon elements of integrated circuits, for example gates (24) or interconnects, are provided with metallic silicide layers (26) in order to take advantage of the lower resistivity thereof. The polysilicon elements are defined on an oxide layer (23) disposed on a silicon substrate (20) before polysilicon metallization. After polysilicon metallization the metal and polysilicon are caused to interdiffuse to form silicide layers (26) covering the polysilicon elements (24).
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FIELD OF THE INVENTION
[0001] This invention relates to sealed packaged articles, particularly packaged toys, which toys are activatable within the package so as to demonstrate the desired function of the article. This allows the potential purchaser to view the product, and particularly view lighting effects, or mechanical movement, or the like, even when the toy is packaged. As such, the invention allows customers, particularly parents, to view the operations of the article in a retail store, warehouse or the like, prior to making a purchase of the product.
BACKGROUND OF THE INVENTION
[0002] Sealed packaged articles, such as toys for use by children, are commonly purchased while still in the packaging, with the purchaser, typically a parent, having to rely on the description and instructions on the packaging showing how the toy would visually appear in operation. This situation can often lead to disappointment for the child once the toy has been purchased and the packaging removed, typically at home.
[0003] This can lead to the return of the product causing unnecessary expense to the supplier and retailer.
[0004] While the retailer can remove some product from its packaging to demonstrate use of the product, this can result in damage to the display item, and thus resulting in wastage, and potential loss of profits on the display item. There is clearly a need, where possible, for alleviating these issues by providing a means for the parent and child to view the desired result offered by the article, while the article is still packaged. This is particularly true in the use of a multi-functional toy, such as a combination nightlight and flashlight combination.
[0005] While it is known in the art to allow some limited access to the toy, and thus permit some activation of the toy while still in the package, this can lead to damage or other contamination of the product because at least part of the toy is accessible. As such, it would be preferred if the system of the present invention could totally enclosed the toy to be sold.
[0006] As such, to overcome these difficulties, it would be advantageous to provide a packaged product, and preferably, a packaged toy, that could be easily activated while still in the package, but which would be arranged so that the product's functionality was displayed, and preferably, without allowing contact with the toy itself. Further, it would be preferred if the toy could be activated using a simple, low cost device that would not add significant costs to the cost of the pre-existing packaging.
SUMMARY OF THE INVENTION
[0007] Accordingly, it is a principal advantage of the present invention to provide packaging, and most particularly packaging for a toy where the toy is not directly accessible to the public while in the package, but which is activatable while in the preferably closed package.
[0008] The advantages set out hereinabove, as well as other objects and goals inherent thereto, are at least partially or fully provided by the packaging of the present invention, as set out herein below.
[0009] Accordingly, in one aspect, the present invention provides a packaged article comprising in combination, said article which is retained within packing material but having at least a portion of which said article may be visually observed; wherein said article comprises (i) operation means to effect operations of a desired function of said article; and (ii) control means by which said packing operation means is controlled, and wherein said un-open packaged article provides access to said control means in order to effect operation of said operation means and thus produce said desired function.
[0010] The packing material preferably comprises a plastics material, and preferably a package material with at least part of the packaging being a clear, transparent package, by which said article may be visually observed. A preferred arrangement is a package with a cardboard backing, and a clear, plastic front cover which essentially surrounds the article to be sold.
[0011] Further, the packaging material prevents direct access to the article which is contained within the packaging, while allowing the user to have access to the control means.
[0012] Moreover, in a most preferred embodiment, the operation means comprises light generating means and the desired function is the production of light to illuminate an object or display, and preferably illuminate the article in whole or a component thereof. However, other operational means can be displayed, including activation of mechanical or other electrical functions.
[0013] As such, in alternative embodiments the operation means comprises means for effecting mechanical movement of the article or a component thereof, and the desired function is the mechanical movement of the article or a component thereof. Other uses might be for the generation of sound, or the generation of an electro-mechanic effect, such as operation of a toy projector, or the like.
[0014] Preferably, the control means comprises a displacable activatable member, such as, for example, an on-off switch, button or the like. A preferred control means is a contact switch which is normally in contact with the operation means.
[0015] In one embodiment, the packaging provides a suitably located aperture in which the operation means is located, so that the user has direct or indirect access to the operation means. As such, the operation means can be easily accessed, and thus, the control means can be activated. Since the operation means is located within the aperture, the inadvertent activation of the operation means, is minimized. As such, in a preferred embodiment, the operation means is preferably located within the aperture but which is still accessible so as to effect activation and/or deactivation of the operation means.
[0016] In one preferred embodiment, the packaging comprises a biasing means operatively adjacent the operation means, so that the article is positioned in a manner that: (i) the operation means is normally in abutment with the control means; and (ii) the operation means is operably releasable from said control means, by movement away from said control means, and thus out of abutment with said control means, and thus effect activation of the control means.
[0017] Preferably, the biasing means comprises a resiliently flexible member manually operable through the aperture. Most preferably, the biasing means is provided by a plastic member formed from the same material as the packaging material itself.
[0018] Access to operation means could therefore be provided by an opening in the sales box, an opening in a blister pack, a flexible film over a test button that allowed it to be pressed, or the like.
[0019] In alternative embodiments to some of the preferred embodiments defined hereinabove, the control means comprises biasing means in abutment with the displacable activatable member.
DETAILED DESCRIPTION OF THE INVENTION
[0020] In the present application, the term “package” refers to any suitable container, which can include cardboard boxes, metal enclosures, or the like, but most preferably is a plastic container, and most preferably, a clear plastic container. The package is also preferably blow moulded, vacuum formed, or otherwise formed to a suitable shape, such as in a “blister pack”, in order to hold the toy. Numerous examples of this type of plastic packaging are known, and the general production techniques for these types of packaging materials is outside of the scope of this invention.
[0021] Further, while the word “toy” is used throughout the present application, it is clear that the present invention has utility outside of the toy area, and can be modified for use with any type of device that might be activable by a potential user, while the product is still in the package. The skilled artisan will be aware that the packaging of the present invention can be used in a wide variety of applications. However, the present invention is of particular utility when applied to the toy market segment.
[0022] Unless otherwise specifically noted, all of the features described herein may be combined with any of the above aspects, in any combination.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Embodiments of this invention will now be described by way of example only in association with the accompanying drawings in which:
[0024] FIG. 1 is a diagrammatic vertical front sectional view of a toy according to the prior art; and
[0025] FIG. 2 is a diagrammatic vertical front sectional view of a packaged toy shown in FIG. 1 , as retained within packaging, according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] The novel features which are believed to be characteristic of the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention will now be illustrated by way of example only. In the drawings, like reference numerals depict like elements.
[0027] It is expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
[0028] Referring to FIG. 1 , a side view of a combined night light-flash light article 10 is shown within a prior art packaging system 30 . Packaging system 30 includes packaging formed of a clear, rigid plastic film 32 affixed to background cardboard backing 34 bearing descriptive text.
[0029] Article 10 has a light reflecting shaped plastics member 14 positioned on a base 16 above a first LED (not shown). At the bottom of base 16 is a lens 18 , which has a second LED light source (not shown). A switch 20 protrudes through base 16 , and is normally closed when article 10 is standing on a suitable surface, such as a night table, (not shown), after it has been removed from packaging system 30 . In normal operation, when article 10 has been removed from packaging system 30 , and placed on a surface, switch 20 is in its closed position. When article 10 is lifted from the surface, switch 20 is opened causing second LED to be activated, and thus provide light through lens 18 . As such, the article 10 acts as a flashlight.
[0030] When returned to the surface, switch 20 is again closed, and this contact de-activates the second LED. However, first LED now illuminates and shines light into plastics member 14 so as to act as a nightlight. After a pre-set time period, first LED will cease to be illuminated, and the article 10 returns to its off position.
[0031] It will be noted though, that the specific functionality of article 10 is not of importance. It is of primary importance however, that the functionality of article 10 (whatever it might be) can be demonstrated while article 10 is in the package.
[0032] In FIG. 1 , article 10 is shown within a prior art packaging system 30 , and it is difficult within this system 30 to show how article 10 operates without allowing movement of article 10 , or the like. Moreover, for shipping and storage, switch 20 must remain in the closed position so as to conserve battery life, but it is difficult to overcome this requirement when the article is viewed by the consumer without allowing the consumer to open the package or have direct access to the article. As a result, it is not easy for the consumer to fully appreciate the functionality of article 10 .
[0033] FIG. 2 shows the same article 10 within a packaging system 40 , according to the present invention. As in FIG. 1 , packaging system 40 includes packaging formed of a clear, rigid plastic film 50 affixed to background cardboard backing 52 bearing descriptive text. Rigid film 50 is suitably shaped as to essentially follow the contour of most of article 10 . Rigid film 50 has a packaging base 54 and an aperture 56 in film 50 which is adjacent switch 20 .
[0034] A flexible strip 58 made of the same plastic film as that of film 50 , is provided which is retained at one end 60 to packaging base 54 while the other end 62 of strip 58 is located within aperture 56 . At end 60 , a living hinge is formed of the plastic material from film 50 , and is normally biased so that strip 58 will hold switch 20 in its closed position. As a result, strip 58 is integral with film 50 .
[0035] However, end 62 is accessible to allow operable manipulation of strip 58 by a finger. Strip 58 in its resting state is biased so as to abut button 20 and thus simulates having article 10 resting on a table, or the like, by having resiliently flexible strip 58 act against button 20 . However, downward manipulation of strip 58 at its end 62 by finger action moves strip 58 out of abutment contact with button 20 and thus effects activation of the second LED. This simulates the user picking up article 10 from a table top.
[0036] Release of strip 58 causes it to return to its normal position, and once again, abut button 20 . This simulates the user returning article 10 to the table top surface, and thus, de-actives second LED, and initiates the nightlight feature of the article, as previously described. Thus, by simply moving strip 58 , the purchaser can view the full functionality of article 10 without removal of the product from the package, and thus without contacting the article itself.
[0037] As a result, the user is able to view the fully functionality of article 10 without making any contact with article 10 . Moreover, should the user wish to purchase the article, they can be assured that previous potential purchasers have not had direct access to the article.
[0038] In a further preferment, packaging base 54 has an embedded aluminum strip 70 to enhance light reflection from the second LED, and thus, provide an enhanced visual appearance of this function of article 10 .
[0039] In an alternative arrangement, article 10 is a nightlight and flashlight combination, wherein both the first and second LED lights are activated and are illuminated at the same time. As such, movement of strip 58 will cause both LEDs to be activated at the same time.
[0040] Thus, it is apparent that there has been provided, in accordance with the present invention, a toy packaging combination, which fully satisfies the goals, objects, and advantages set forth hereinbefore. Therefore, having described specific embodiments of the present invention, it will be understood that alternatives, modifications and variations thereof may be suggested to those skilled in the art, and that it is intended that the present specification embrace all such alternatives, modifications and variations as fall within the scope of the appended claims.
[0041] Additionally, for clarity and unless otherwise stated, the word “comprise” and variations of the word such as “comprising” and “comprises”, when used in the description and claims of the present specification, is not intended to exclude other additives, components, integers or steps. Further, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.
[0042] Moreover, the words “substantially” or “essentially”, when used with an adjective or adverb is intended to enhance the scope of the particular characteristic; e.g., substantially planar is intended to mean planar, nearly planar and/or exhibiting characteristics associated with a planar element.
[0043] Further, use of the terms “he”, “him”, or “his”, is not intended to be specifically directed to persons of the masculine gender, and could easily be read as “she”, “her”, or “hers”, respectively.
[0044] Also, while this discussion has addressed prior art known to the inventor, it is not an admission that all art discussed is citable against the present application.
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A packaged article comprising in combination the article retained within packing having at least a portion by which the article may be visually observed; wherein the article has (i) operation means to effect operations of a desired function of the article; and (ii) control means by which the packing operation means is controlled and the packing allows of access to the control means to effect operation of said operation means to produce the desired function. As a result, the desired function of the article can be tested and seen by a potential purchaser even though the article is still sealed in its package.
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BACKGROUND OF THE INVENTION
The present invention relates to a method of operating an elevator system, and an elevator system in which this method can be used.
Usually, elevator systems are used in which the elevator car is raised and lowered by means of a rope. Typically used as rope is a steel suspension rope that runs over a rope sheave and at one of its ends is connected to the elevator car and at its other end to a counterweight. The rope sheave is driven by an electric motor, the rope sheave raising the elevator car when the motor turns in one direction, and the rope sheave lowering the elevator car when the motor turns in the other direction. Between the drive motor and the rope sheave, a reduction gear can be provided. Typically, the drive motor is also provided with a control unit. The rope sheave, the drive motor, and a control system are usually arranged in a machine room above the elevator hoistway.
The elevator car and the counterweight hang on mutually opposite sides of the rope sheave. The weight of the counterweight usually corresponds approximately to the weight of an elevator car that is 40% full. If the elevator car is 40% full, the result is that only little energy is needed to move the elevator car. In such a case, the drive motor serves mainly to overcome friction. If the weight of the elevator car is approximately equal to the weight of the counterweight, this results in an approximately constant level of potential energy in the overall system. When the potential energy of the elevator car falls as a result of the elevator car being lowered, the potential energy of the counterweight increases correspondingly as a result of its being raised, and vice versa.
This normally used elevator system has the disadvantage that additional building space is required for the counterweight. Also, the moment of inertia of the counterweight can cause undesired positional changes of the elevator car.
These disadvantages can, however, be avoided by the rope, or a corresponding means of suspension, being wound around a drum that is provided for this purpose, instead of passing over a rope sheave and being connected on the other side to a counterweight. Such an elevator system is known from German patent application 2136540. Known from this application is an elevator system with a drive drum in which the suspension belt that is used as a suspension means is stored. The arrangement of a counterweight can thereby be obviated. The suspension belt is driven by positive engagement and does not depend on higher coefficients of friction between the suspension belt and the drive drum.
From U.S. Pat. No. 6,305,499 B1 an elevator system is known that also has a drum on which the suspension means is rolled so that a counterweight can be obviated. The drum is arranged in the elevator hoistway. The suspension means is fastened to a wall of the elevator hoistway, runs over two rope sheaves that are arranged on the elevator car, and is rolled onto the drum through an opening in another hoistway wall.
Since in the known elevator system with drum, the suspension means is rolled onto the drum at a constant rotational speed, the speed of the elevator car changes depending on the length of the suspension means already rolled onto the drum. As the elevator car rises, the suspension means is rolled onto the drum, as a result of which the diameter of the roll of suspension means on the drum continually increases, which in its turn results in an increase in the speed of the car. When the elevator car travels down, the diameter of the roll of suspension means decreases, with the consequence that the speed of the elevator car reduces. If the speed of rotation of the drive unit is constant, the speed of the elevator car thus depends on the position of the elevator car. This results in a low level of comfort for the user.
SUMMARY OF THE INVENTION
It is a task of the present invention to create a method of operating an elevator system with a drum for uptake of a suspension means whose use results in a high level of comfort for the user. It is a further task of the present invention to provide an elevator system that is particularly suitable for use of the method according to the present invention.
The present invention solves the task by providing a method wherein a speed of rotation of the drive unit that serves to drive the drum is defined by a control unit that serves to control the drive unit depending on a length of the belt that is rolled onto the drum. The control unit can also be a feedback control unit.
The method according to the present invention has the advantage that the speed of rotation of the drive unit is defined by the control unit in such manner that the speed of the elevator car is essentially constant. This is experienced by the passenger as pleasant, and results in an increase in comfort for the user. Since the drum takes up the suspension means, a counterweight can be dispensed with. By this means, slipping effects resulting from the moment of inertia of the counterweight are avoided. The position of the elevator car can be determined from the length of the suspension means rolled onto the drum.
In a first embodiment of the present invention, the length of the suspension means that is rolled onto the drum is determined from an absolute number of turns of the drum. The absolute number of turns of the drum is to be understood as the difference between the number of turns of the drum when raising the elevator car and the number of turns of the drum when lowering the car. The length of the suspension means that is rolled onto the drum and/or the absolute number of turns is preferably determined by a value encoder that is assigned to the drive unit and which may particularly be an impulse encoder and/or a rotational speed encoder. Additionally, or alternatively, the length of the suspension means that is rolled onto the drum and/or the absolute number of turns from a position of the elevator car in an elevator hoistway can be determined by a value encoder, particularly a positional value encoder, that is arranged in the elevator hoistway or on the elevator car.
In a further development of the present invention, after each turn of the drum, a rotational speed is prescribed by the control unit. A turn of the drum is to be understood as a complete turn, in other words a turn through 360°. This has the advantage that the rotational speed of the drive unit is adapted to the length of suspension means that is rolled onto the drum as nearly as possible in real time.
In a further embodiment of the present invention, the suspension means is rolled onto the drum spirally. This means that on each turn, the suspension means comes to rest on itself. The segments of the suspension means that form a turn do not come to rest on the drum side by side. This has the advantage that essentially the width of the drum need only be the same as the width of the suspension means.
The elevator system according to the present invention is characterized in that a control unit for controlling the drive unit is provided that is executed in such manner that it can determine a rotational speed of the drive unit from the length of suspension means that is rolled onto the drum. This has the advantage that by adaptation of the rotational speed of the drive unit, the speed of the elevator car can be held essentially constant.
To determine the number of turns, a value encoder that is assigned to the drive unit and/or a value encoder that is assigned to the elevator car and/or to the elevator hoistway can be used, the value encoder serving to determine the position of the elevator car in the elevator hoistway, from which, in turn, the number of turns can be determined.
Preferably, absolute encoders are used that need no initialization, with which the elevator car is moved into a starting position and the control unit sets the absolute number of turns to zero. An absolute value encoder stores, for example, an absolute number of turns already executed during commissioning as also a number of turns executed after a power outage.
DESCRIPTION OF THE 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 a preferred embodiment when considered in the light of the accompanying drawings in which:
FIG. 1 is a perspective view of a prior art elevator system with a counterweight;
FIG. 2 is a perspective schematic representation of an elevator system with a drum to take up a suspension means according to the present invention; and
FIG. 3 is a schematic representation of an Archimedean spiral.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the figures, identical reference numbers indicate functionally identical components.
FIG. 1 shows a prior art elevator system 1 as it is normally used. The elevator system 1 comprises an elevator car 2 , a counterweight 3 , a suspension means 4 , and a machine room 5 that is arranged above an elevator hoistway 6 . Used as the suspension means 4 is, for example, a rope, a belt, or a flat belt. The suspension means 4 is connected at one of its ends to the elevator car 2 and at its other end to the counterweight 3 , and passes over a rope sheave 7 that is arranged in the machine room 5 . The rope sheave 7 is driven by a drive unit 8 , for example an electric motor, that is in turn controlled by a control unit 9 .
For the counterweight 3 , additional building space is required. To save this building space, in an elevator system 10 according to the present invention as shown in FIG. 2 , a drum 11 is used that is preferably arranged in the machine room 5 and onto which the suspension means 4 can be rolled. The suspension means 4 can consist of several suspension means that run in parallel. Assigned to the drum 11 is a drive unit 12 , the drum 11 and the drive unit 12 being preferably integrated into a unit. The drive unit 12 is controlled by a control unit 13 .
The suspension means 4 is rolled onto the drum 11 , preferably in the form of a so-called Archimedean spiral r(p) as shown exemplarily in FIG. 3 . An Archimedean spiral is characterized by a constant distance between turns over its entire defined area. In the elevator system that is represented in FIG. 2 , this constant distance between turns results from the constant thickness of the suspension means 4 .
In the elevator system 1 according to FIG. 1 in which the suspension means 4 is only diverted once over the rope sheave 7 , and in which the rope sheave has a known and constant diameter “D”, the control unit 9 determines from a reference speed “S” a rotational speed “R” of the drive unit 8 , preferably in the unit revolutions per minute, according to the following formula,
R
(
s
)
=
S
D
π
,
where π is the constant 3.1416.
In the elevator system 10 according to FIG. 2 , in which the suspension means 4 is rolled onto the drum 11 , calculation of the rotational speed according to this formula would, however, have the effect that with decreasing height the elevator car would fall at ever decreasing speed, and with increasing height would rise at ever increasing speed. To avoid this change in the car speed, in the method according to the invention, when determining the rotational speed “R”, the length of suspension means 4 that is rolled onto the drum 11 is taken into account.
The length of an Archimedean spiral r(p), as illustrated in FIG. 3 , is calculated according to the following formula:
L
=
1
2
a
(
p
1
+
p
2
+
ln
(
p
+
1
+
p
2
)
)
,
where
p
=
2
n
π
,
where “a” is the thickness of the suspension belt 4 , “n” is the absolute number of turns of the drum, and “p” is the angle in the plane polar coordinate system in which the spiral lies. Taking into account the diameter “D” of the drum 11 , the length of the spiral
L
=
L
1
-
L
2
where
L
1
=
1
2
a
(
p
1
+
p
2
+
ln
(
p
+
1
+
p
2
)
)
where
p
=
(
D
/
2
a
+
n
)
2
π
,
and
L
2
=
1
2
a
(
q
1
+
q
2
+
ln
(
q
+
1
+
q
2
)
)
where
q
=
(
D
/
2
a
)
2
π
.
The rotational speed “R” is preferably newly defined after each turn of the drum 11 . For this new definition of the rotational speed, the length or segment of the suspension means 4 must be taken into account that was rolled onto the drum 11 during the last turn. This rolled-on length per turn “Z” is given by Z=Z1−Z2 where
Z
1
=
1
2
a
(
p
1
+
p
2
+
ln
(
p
+
1
+
p
2
)
)
where
p
=
(
D
/
2
a
+
n
)
2
π
,
and
Z
2
=
1
2
a
(
q
1
+
q
2
+
ln
(
q
+
1
+
q
2
)
)
where
q
=
(
D
/
2
a
+
m
)
2
π
,
where m=n−1 and m=0 when n<1.
The control unit 13 then determines the rotational speed “R” of the drive unit 12 for the drum 11 from a predefined reference speed “S” that is divided by the rolled-on length “Z” of the suspension means 4 per turn of the drum 11 according to the following formula
R
(
s
,
n
)
=
S
N
and thereby prescribes the rotational speed “R” that is obtained to the drive unit 12 . The reference speed “S” can, for example, be prescribed by the user or by the supplier of the elevator system.
The control unit 13 controls the drive unit 12 and thereby the drum 11 to the prescribed rotational speed “R”. The control unit 13 can be executed so that it regulates the drive unit 12 and/or the drum 11 to the prescribed rotational speed “R”.
The length “Z” depends on the absolute number “n” of turns since commissioning. To determine this absolute number “n” of turns, a value encoder 14 , preferably an impulse encoder, can be provided on the drive unit 12 and/or on the drum 11 . To initialize the value encoder 14 , the elevator car can be caused to travel to a starting position which may be, for example, the bottommost story, and the control unit 13 resets the absolute number “n” of turns to zero. A sensor unit 15 can be provided, that is provided in the elevator hoistway 6 and that is preferably based on a magnetic measuring principle, that communicates to the control unit 13 when the elevator car 2 has reached the starting position.
The absolute number “n” of turns can also be determined from the position of the elevator car 2 in the elevator hoistway 6 . For this purpose, it is preferable for a position encoder 16 to be arranged in the elevator hoistway 6 and/or on the elevator car 2 . This must also be initialized according to the principle described. From the determined position of the elevator car 2 , that results in turn from the length of the rolled-on suspension means 4 , the control unit 13 then determines the absolute number “n” of turns of the drum 11 .
To avoid the initialization, the value encoders 14 and/or 16 can also be executed as absolute value encoders that have stored the absolute number “n” of rotations that, for example, were already executed during commissioning, or after a power outage.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
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A method of operating an elevator system with a drum for taking up a suspension device, a drive unit for driving the drum, and a control unit for controlling the drive unit, includes operating the control unit of the drive unit to prescribe a rotational speed that depends on a length of the suspension device that is rolled onto the drum. Also included is an elevator system in which the method can be used.
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FIELD OF THE INVENTION
[0001] This invention relates to bridge plug tools and to methods of operating bridge plug tools. Such tools and methods find use in oil and gas wells or the like.
BACKGROUND
[0002] Bridge plugs can be installed in pressurized wells, such as hydrocarbon well, to seal off a portion of the well, or to provide a barrier preventing flow of hydrocarbons from the well, or to prevent flow of gas, oil or water between zones down hole. Bridge plugs are usually set using an external setting tool to generate an axial force in the tool, resulting in radial expansion of an anchoring mechanism and a packer element towards the tubular inner wall. When the axial force provided by the setting tool reaches a predetermined level, the setting tool is disconnected from the plug and pulled out of the well, while the plug remains fixed to the casing or tubing down hole. The packer seals differential pressure above and below the tool and the anchoring mechanism prevents movement of the plug during the differential pressure period. A retrievable bridge plug is usually retrieved by lowering a pulling tool into the well. By mechanical manipulation, the pulling tool is latched to a fishing neck at the top of the tool, the plug is released from the tubing or casing, and pulled out of the well.
[0003] One problem in the use of such tools is the risk of retrievable plugs getting stuck when trying to release the plugs out of hole after having been used in a period for sealing differential pressure down hole. Problems with retrieving bridge plugs can include:
[0004] a) Sand or debris entering into vital parts in the release system and thereby preventing proper functioning of the mechanical. Sand, and/or debris can land on top of the plug as a result of fluid flow during equalizing carrying particles from the reservoir, perforation operations in the well above the plug, pressure testing causing scale and particles to fall down, fracturing operations with sand, or other operations that can cause settling of solids over the plug.
[0005] b) Deformation of elastomer in the plug such as swelling or permanent set caused by chemical and/or temperature effects on the material.
[0006] c) Explosive decompression in the elastomer element causing damage and/or deformation of the elastomer element.
[0007] d) Gap corrosion of sleeves in the tool that may over time prevent the proper function of release mechanisms, or sand building up in the annulus between a setting sleeve and the tubing or casing inner diameter.
[0008] Patents describing retrievable bridge plugs include U.S. Pat. No. 4,359,090, US2004/00244966, US2010/0186970, US2010/0019426, US2008/0060821, US2010/0288508, U.S. Pat. No. 7,290,603.
[0009] Equalizing systems, allowing the pressure above and below the tool to equalize exist in several known down hole tools in the form of ball valves sliding sleeves, shear screws, etc. One such system includes a long internal tube connecting an equalizing piston, below the packer to the fishing neck and operates by moving the fishing neck down.
SUMMARY
[0010] One aspect of this invention comprises a bridge plug tool for use in a well, comprising: a tool body; a mandrel extending through the tool body; a setting sleeve positioned on the tool body; a packer module located below the setting sleeve, the packer module having an expanded position in which its outer surface is expanded radially with respect to the tool body and a contracted position in which its outer surface is substantially the same as that of the tool body; and an anchor module located blow the packer module, the anchoring module comprising anchor elements moveable between an expanded position in which the anchor elements extend radially from the tool body and a contracted position in which the anchor elements are substantially aligned with the surface of the tool body; wherein the mandrel extends through the sleeve, packer module and anchor module; the mandrel and setting sleeve are relatively moveable between an axially extended position and an axially contracted position; and wherein the mandrel and setting sleeve engage the anchor module and packer module such that relative movement of the mandrel and setting sleeve between the axially extended and axially contracted positions correspondingly moves the anchor module and packer module between the respective contracted and expanded positions. The use of the sleeve and mandrel arrangement allows setting and release mechanisms to be protected from the external environment of the tool.
[0011] The anchor elements can comprise a series of slips arranged around the tool body that in use engage the wall of the well when in the extended position to prevent further movement of the tool in the well. The anchor module can comprise actuators that are mounted on the tool body to be axially moveable relative thereto by means of the mandrel and setting sleeve, the actuators comprising inclined surfaces that engage corresponding surfaces on the slips and force them radially outwards when the mandrel and setting sleeve are contracted. The actuators can comprise upper and lower subs mounted above and below the slips and positioned around the tool body. The actuating mechanism can therefore be within the tool and protected from the external environment.
[0012] The packer module can comprise a packer and upper and lower packer supports, the packer supports being engaged with the mandrel and sleeve such that contraction of the mandrel and packer acts to expand the packer.
[0013] The tool can further comprise a locking mechanism for holding the setting sleeve and mandrel in the contracted position. The locking mechanism can comprise a ratchet sleeve which extends into and engages the setting sleeve, and locking dogs located within the ratchet sleeve which engage the mandrel. A release mechanism can also be provided for releasing the mandrel and sleeve from the contracted position. The release mechanism can comprise a release sleeve which extends within the ratchet sleeve and is axially moveable to allow the locking dogs to disengage from the mandrel. The provision of the various sleeves again protects the release mechanism from the external environment.
[0014] In one embodiment, the mandrel comprises a main part and an extension part connected by means of a threaded engagement, wherein the extension part engages the tool body such that rotation of the main part extends the extension part by the action of the thread so as to provide relative movement of the mandrel and the sleeve to the extended position.
[0015] The mandrel can provides a fluid flow path with an opening at the bottom of the tool body, the tool further comprising a connection at the top of the mandrel surrounded by a fishing neck above the setting sleeve, wherein the connection and the fishing neck each have one or more ports and are relatively moveable so that the ports can be brought into alignment to allow fluid communication though the mandrel to the exterior of the tool body above the packer module. The fishing neck can be axially or rotationally moveable to bring the through holes into alignment. In this manner, any pressure difference above and below the packer can be equalized while the packer is still engaged with the well wall. Additionally or alternatively, a portion of the wall of the tool body can be provided that can be broken to allow fluid communication between the interior and exterior of the tool body.
[0016] The invention also provides a method of operating the tool, comprising: positioning the tool in a well at a predetermined location with the mandrel and setting sleeve in the extended position and the anchor and packer modules in contracted positions; initially contracting the mandrel and setting sleeve to expand the anchor module to engage the wall of the well and anchor the tool in position; further contracting the mandrel and setting sleeve by movement of the setting sleeve over the mandrel to expand the packer module to seal against the wall of the well; and securing the mandrel and setting sleeve in the further contracted position.
[0017] The method can further comprise opening one or more ports above the packer to allow fluid communication through the tool across the packer so as to equalize any pressure difference. The opening of the one or more ports can be achieved by relative axial or rotational movement of a fishing neck and connection located at the top of the tool. Alternatively, or in addition, the opening of the one or more ports can be achieved by breaking or perforating a portion of the wall of the tool body.
[0018] The method can further comprise moving the setting sleeve and mandrel to the extended position to move the packer module and anchor module to their respective contracted positions to disengage the anchor module from the wall of the well and release the seal of the packer module against the wall of the well. In one embodiment, moving the setting sleeve and mandrel can comprises releasing the setting sleeve from the mandrel. Moving the setting sleeve and mandrel can additionally or alternatively comprise rotating the mandrel to operate a screw thread to extend a portion of the mandrel relative to the setting sleeve.
[0019] Further aspects of the invention will be apparent from the following description.
BRIEF DESCRIPTION OF DRAWINGS
[0020] FIG. 1 shows a tool according to one embodiment of the invention;
[0021] FIG. 2 shows a part-sectioned view of the tool of FIG. 1 as run into the well;
[0022] FIG. 3 shows the tool in its set configuration;
[0023] FIG. 4 shows the tool in an equalized configuration;
[0024] FIG. 5 shows the tool in a released configuration;
[0025] FIG. 6 shows the tool in an alternative released configuration; and
[0026] FIG. 7 shows a setting adapter for use with the tool.
DETAILED DESCRIPTION
[0027] The invention provides a retrievable bridge plug for use in oil or gas wells, where sand and debris can be prevented from entering into the pressure equalizing and/or release system. Pulling a mandrel relative to a locking system can radially expand slips and a packer with a force sufficient for resisting the pressure difference across the packer element. Pushing a mandrel relative to the locking system, or elongation of the mandrel can result in contraction of the packer element and slips. The elastomeric packer can be provided with an extrusion barrier and the slips anchoring system enables the tool to be used in high pressure and high temperature applications (e.g. 10,000 psi and up to 200 degrees Celsius) and in well with high concentrations of H 2 S and CO 2 (e.g. 40% H 2 S and 20% CO 2 ). Such down hole conditions often require the use of sophisticated materials. Although such materials can withstand the chemical degradation, they also make milling operations a lot more complicated as the milling equipment can be rapidly worn down due to the machinability of the materials. However, it will be appreciated that this invention is not limited to such uses and can be used in any environment.
[0028] In embodiments of the tool according to the invention, equalization of differential pressure and release can be achieved by latching a pulling tool on to an external fishing neck by using a standard pulling tool. Equalization of the pressure across the plug can be achieved by downward movement of the pulling tool. Releasing the plug can be achieved by upward movement of the pulling tool. The structure of the tool prevents sand or debris can from falling into the equalizing system and the release mechanism.
[0029] In one embodiment primary release can be achieved by using straight upward pulling of a fishing neck after having completed pressure equalization. A backup equalizing method is to rotate the top connection of the mandrel in a predetermined direction by an external torque generating equalizing tool conveyed, for example, on slick line, coiled tubing or drill pipe.
[0030] A backup release system can also be provided. An external torque generating release tool, conveyed in a similar manner to the external equalizing tool, can provide the secondary release in cases where, for example, the fishing neck is prevented from upward movement. A rotation of the fishing neck relative to the mandrel (for example, in the opposite direction to that used for the backup equalization method described above) will cause the mandrel to be elongated by action of a screw thread, resulting in a radial contraction of packer element and slips. Should the primary and secondary release systems both be damaged, the tool can be configured such that a short milling operation is needed to release the plug, in the event of a plug stuck in hole.
[0031] FIG. 1 shows a general view of the tool body of an embodiment of the invention, in the configuration in which the tool is run into the well. In this configuration, the tool has a substantially constant outer diameter to reduce the likelihood of hang-ups when running into the well and accidental setting before the tool reaches the desired location. FIG. 2 shows further internal detail of the tool in this configuration. A mandrel 3 extends through the interior of the tool body. A top connection 1 is provided at the upper end of the mandrel 3 and provides a latching mechanism for connection to a setting or release tool, and a series of ports extending through the side wall thereof (described in further detail below). A bull nose 20 is provided at the lower end of the mandrel 3 which provides fluid access to the interior of the mandrel from below the tool body.
[0032] A setting sleeve 2 is positioned at an upper part of the tool body around the mandrel 3 . The mandrel 3 and setting sleeve 2 can be moved axially relative to each other as will be described below.
[0033] A packer module is located in the tool body below the setting sleeve 2 and comprises a packer 4 with upper and lower packer supports 5 , 6 positioned around the tool body and located on either side of the packer 4 . The packer supports 5 , 6 can comprise an extrusion barrier of the type described in GB1018334.1. The setting sleeve 2 engages the upper packer support 5 .
[0034] An anchor module is located below the packer module and comprises a series of slip elements 9 located around the tool body within an external tube 12 which has corresponding slots to allow the slip elements 9 to project radially outwardly from the tool body. Upper and lower slip subs 10 , 11 are positioned around the tool body on either side of the slip elements 9 . The slip subs 10 , 11 have inclined surfaces which engage corresponding surfaces on the slip elements 9 such that when the slip subs 10 , 11 are urged together, the slip elements 9 are caused to project through the holes in the sleeve 12 . The upper slip sub 10 engages the lower packer support 6 and the lower end of the mandrel 3 is connected to the lower slip sub 11 by means of a tension ring 21 .
[0035] Axial movement of the mandrel 3 and setting sleeve 2 , such that the setting sleeve 2 is contracted towards the lower end of the mandrel 3 will have the effect of urging the upper and lower slips subs 10 , 11 and upper and lower packer supports 5 , 6 respectively towards each other, causing expansion of the slips 9 and packer 4 (see FIG. 3 ). Similarly, axial movement of the mandrel and setting sleeve 2 such that the setting sleeve 2 is extended away from the lower end of the mandrel 3 will have the effect or releasing the force causing expansion of the packer 4 and slips 9 allowing them to contract. Such axial movement of the mandrel 3 and setting sleeve 2 can be provided by means of a setting tool of the type shown in FIG. 7 , which engages the top connection 1 (for example, by means of the internal groove 1 b in the upper end of the connection 1 ) and setting sleeve 2 . The setting tool can pull on the mandrel 3 while holding the setting sleeve 2 to contract the mechanism.
[0036] A locking mechanism is provided around the upper part of the mandrel 3 to hold the mandrel 3 and setting sleeve 2 in the contracted configuration, once set (see FIG. 3 ). The locking mechanism comprises a ratchet tube 7 over which the setting sleeve 2 moves. The setting sleeve 2 has a ratchet ring 19 on its inner surface which engages the outer surface of the ratchet tube 7 . The ratchet tube 7 is connected around the mandrel 3 together with a lock tube 8 and locking dogs 14 which engage in slots in the mandrel 3 and lock tube 8 . A release sleeve 15 is positioned around the upper part of the mandrel 3 , extending inside the setting sleeve 2 and around the lock tube 8 so as to prevent the locking dogs 14 from moving out of the slots in the mandrel 3 and disconnecting the mandrel 3 from the setting sleeve 2 .
[0037] A fishing neck 17 is positioned around the top connection 1 above the release sleeve 15 , to which it is connected by means of a shear screw. The shear screw and the locking dogs 14 prevent the release sleeve from moving during setting operations and when under differential pressure when the tool is set. Through ports are provided in the side wall of the fishing neck 17 .
[0038] The tool can be deployed down hole by using deployment methods such as slick line, tractors, coiled tubing or drill pipe. A setting tool (with a setting adapter, see FIG. 7 , that fits into the groove 1 b ) can be used to generate axial movement for installation. During installation in a well, the setting tool (not shown) generates a pulling force on the mandrel 3 and a pushing force on the setting sleeve 2 resulting in a movement of the mandrel 3 upwards after shearing a shear screw. The packer element 4 and the packer support 5 , 6 are initially prevented from movement and expansion by shear screws 5 a and 6 a . The movement of the mandrel 3 relative to the setting sleeve 2 , the packer 4 and packer supports 5 , 6 will result the slips subs 10 and 11 being pushed towards each other. This movement results in the slips 9 being pushed radially outwards by the inclined surfaces on the slips 9 and slips subs 10 and 11 . The external tube with slots 12 secures alignment of the slips 9 during expansion and prevents particles from entering enter the mechanism. When the outer surface of the slips 9 reaches the inner wall of the well (not shown), the mandrel 3 will be prevented from moving further upwards, and the setting sleeve 2 will start to move downwards. This will result in shearing of shear screws 5 a and 6 a , allowing the packer element 4 to be compressed and start to expand radially, and the packer supports 5 , 6 on each side of the packer 4 to move radially towards the tubing inner wall. The shear screw 6 a can be calibrated to shear at a lower force than the shear screw 5 a to avoid friction between the packer 2 and the well wall during the setting sequence. The packer supports 5 and 6 can assist in centralizing the packer element 2 and the top of the plug inside the tubing. The ratchet ring 19 moves over the ratchet tube 7 and prevents the setting sleeve 2 from moving backwards after the setting tool is released, thus maintaining the force on the slips 9 and packer 4 during operations in such a way that the tool does not move in the wellbore when exposed to differential pressures above and below the tool. The plug can withstand pressure build up from both sides. When the setting force has reached a predetermined level during the installation, a calibrated shear disc is sheared, resulting in a disconnection of the setting tool from the plug.
[0039] Springs 13 located between the bull nose 20 and lower slips sub 11 secures the packer and anchor modules are kept in compression against the ratchet locking mechanism after the setting tool has been released from the tool and during pressure reversals.
[0040] Fluid under the tool can enter the interior of the mandrel 3 through the holes in the bull nose 20 . However, flow through the mandrel above the tool is normally blocked, ensuring pressure isolation above and below the tool. When the pressure under the tool increases relative to the pressure over the plug, the slips 9 prevent upward movement of the tool in the wellbore, as the lower slips sub 11 will push the slips radially towards the tubing or casing wall, increasing the anchoring force. The slips 9 are designed to avoid damaging the tubing wall. The packer element 4 will be prevented from movement or extrusion by the upper expanded packer support 5 . The extrusion gap between the tool outer body and the well inner diameter is completely covered mechanically by the expanded packer supports 5 and 6 . This allows for the use of sophisticated elastomeric material with excellent performance in sour environments such as FKM, EPDM, and FFKM. These materials often have poor mechanical properties but may be damaged should there otherwise be any extrusion gap between the plug outer body and the well, tubing or casing inner wall. The packer module is prevented from movement by the ratchet ring 19 and the locking dogs 14 that connect the sleeve 2 , the ratchet tube 7 , the lock tube 8 and the mandrel 3 . During pressure from below the tool, the mandrel 3 is prevented from moving by the slips 9 . The position of the fishing neck 17 , which closes the ports on the top connection 1 prevents pressure from below the tool from leaking through the mandrel 3 . The radial ports in the top connection 1 and seals ensure a completely pressure equalized fishing neck 17 during pressure reversals.
[0041] When the pressure over the tool increases relative to the pressure below the tool, the slips 9 will prevent downward movement of the plug in the wellbore, as the upper slips sub 10 will push the slips 9 radially towards the tubing or casing wall in a similar manner as described above.
[0042] In order to aid in retrieval of the tool, the pressure above and below the tool can be equalized. The main method of equalizing by latching a pulling tool (not shown) on to the external fishing neck 17 . The fishing neck 17 has external neck to which the pulling tool can be secured, even if debris or sand is present on top of the mandrel top connector 1 . The length of the fishing neck 17 may be elongated if major quantities of sand or debris are expected in the well, to enable latching on to the fishing neck 17 without having to run bailers or to circulate fluid to clear the debris. The fishing neck 17 slides freely axially on the top connection 1 to stop particles entering between them. A shear screw prevents movement of the fishing neck 17 before the pulling tool is fully engaged. By jarring down with a relatively low force, the fishing neck 17 is moved downwards relative to the mandrel top connector 1 . This axial movement will cause the equalizing ports in the mandrel top connector 1 to be aligned with the ports in the fishing neck 17 (see FIG. 4 ). When the holes are aligned, differential pressure on either side of the tool can be equalized. The pressure drop and flow may be restricted by using nozzles in the ports in the mandrel top connector 1 so as to control the effect of rapid explosive decompression in the packer 4 and seals. This effect can otherwise damage the elastomer, as gas that has migrated into the elastomer at high pressure, can otherwise expand inside the elastomer when the external pressure drops rapidly and un-controlled, and may result in retrieving problems.
[0043] If pressure equalization is not possible using the method described above, a backup method can be provided. The top connection 1 has grooves 1 b that can be used for creating torque from an external equalizing tool (not shown). By rotating the top connection 1 in a predetermined direction (e.g. anticlockwise), the top connection 1 will be moved up relative to the mandrel 3 by a screw action causing the seals between the mandrel 3 and the top connection 1 to be disengaged. A radial hole in the top connection 1 allows pressure to bleed off below the top connection 1 without disengaging the threads connecting the top connection 1 and the mandrel 3 . The top connection 1 is made with a relatively thin wall to withstand the differential pressures towards the mandrel 3 . Although designed for holding high differential pressures, the wall can also be punctured by using a jar and a puncturing tool. The wall may also be replaced by a separate sealed disc with a material such as glass, should a puncturing equalizing method be preferred. This operation will not result in the release of slips 9 from the tubing wall during equalization.
[0044] Finally, by using a drill deployed separately by coiled tubing, wire line tractor or drill pipe, equalizing of the tool can be achieved by drilling through the mandrel top connection 1 . By drilling such a hole, the pressure differential across the tool can be equalized. This operation also will not result in the release of slips 9 from the tubing wall during equalization.
[0045] Once pressure has been equalized, the tool can be released and retrieved. When the fishing neck 17 is pulled upwards relative to the mandrel 3 , the release sleeve 5 is also pulled up, allowing the locking dogs 14 to move radially away from the mandrel 3 . The profile of the connection between the locking dogs 14 and mandrel 3 forces the locking dogs 14 to move away from the mandrel 3 and thereby release the mandrel 3 from locking tube 8 . This releases the compression in the plug, and causes the mandrel 3 to move down relative to the setting sleeve 2 due to gravity. The slips 9 have an outer chamfer that forces the slips radially inwards by the now released weight of the mandrel 3 and bull nose 20 . Jarring upwards on the fishing neck 17 will also assist in the contraction of packer 4 , packer support 5 , 6 and slips 9 (see FIG. 5 ). The mandrel 3 has grooves extending from the initial location of the locking dogs up to the top connection 1 . Should there be a need to push the tool downward into the well, the locking dogs 14 will reengage into the grooves near the top connection 1 . This will ensure that the slips 9 , packer support 5 , 6 and packer 4 cannot be reset down hole after having been released.
[0046] Should it not be possible to move the release sleeve 15 upwards by pulling the system, a backup release method can be provided. By rotation of the mandrel 3 relative to the locking dogs 14 , the mandrel 3 can be elongated, resulting in the reduction and removal of the compression force used to set the packer 4 , packer supports 5 , 6 and slips 9 . This function is obtained through a threaded connection between the mandrel 3 and the mandrel extension 3 b at the lower end of the mandrel. The top connection 1 and the fishing neck 17 have slots where a release tool (not shown) can be installed. The release tool can generate a torque on the mandrel, while at the same time preventing the locking dogs 14 from rotating. The connection between the release sleeve 15 and the lock tube 8 allows an external torque to be applied on the mandrel 3 . The mandrel extension 3 b is prevented from rotation by slots in the upper and lower slips subs 10 , 11 . By applying a torque on the mandrel 3 , the mandrel extension 3 b will therefore move axially downwards relative to the locking dogs 14 . This axial movement will remove the compression on the plug by pulling down the lower slips sub 11 . Should the tool continue to be stuck, a downward jarring on top of the mandrel 3 results in shearing a weak point the tension ring 21 . At this stage, the mandrel can be pushed downwards and dropped. A catcher mechanism can be installed in the upper slips sub 10 to prevent the mandrel 3 from falling to the bottom of the well. The primary and secondary release can be done on slick line, coil tubing, well tractor etc. The top of the plug is however made in such a way that milling to release the ratchet system or the mandrel can be done with limited milling distances.
[0047] During retrieval, the packer 4 and slips 9 are contracted by the weight of the mandrel 3 , top connection 1 and bull nose 20 , which serve to pull the mandrel down under the effect of gravity. The packer 4 is mechanically connected to the packer support 5 in such a way that should the packer 4 meet a restriction on the way out of the hole, an increased puling force created by slick line, coiled tubing or well tractor, will result in a mechanical pulling directly on the upper side of the elastomeric packer element 4 rather than expanding the packer and re-setting the tool.
[0048] Further changes can be made within the scope of the invention .
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A bridge plug tool for use in a well, comprising: a tool body; a mandrel ( 3 ) extending through the tool body; a setting sleeve ( 2 ) positioned on the tool body; a packer module ( 4,5,6 ) located below the setting sleeve, the packer module having an expanded position in which its outer surface is expanded radially with respect to the tool body and a contracted position in which its outer surface is substantially the same as that of the tool body; and an anchor module ( 9,10,11 ) located below the packer module, the anchoring module comprising anchor elements moveable between an expanded position in which the anchor elements extend radially from the tool body and a contracted position in which the anchor elements are substantially aligned with the surface of the tool body; wherein the mandrel extends through the sleeve, packer module and anchor module; the mandrel and setting sleeve are relatively moveable between an axially extended position and an axially contracted position; and wherein the mandrel and setting sleeve engage the anchor module and packer module such that relative movement of the mandrel and setting sleeve between the axially extended and axially contracted positions correspondingly moves the anchor module and packer module between the respective contracted and expanded positions. The use of the sleeve and mandrel arrangement allows setting and release mechanisms to be protected from the external environment of the tool.
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TECHNICAL FIELD
[0001] The invention relates to a double seat valve, the seats of which can be cleaned, with two serially arranged closing elements which can be moved relative to one another and which in the closed position of the double seat valve prevent overflow of fluids from one valve housing part into another, which border between themselves both in the closed and also in the open position a leakage cavity which is connected to the vicinity of the double seat valve, in the closed position the first closing element which is made as a slide piston being accommodated to form a seal in a connection opening which joins the valve housing parts to one another and in the course of its opening motion making sealing contact with a second closing element which has a second seal and which is associated with the second seat surface, and the latter closing element in the continued opening motion being likewise transferred into the open position, the first closing element in its end section having a first seal which radially seals relative to a cylindrical first seat surface which is made in the connection opening, the second closing element on its end facing the first closing element having a recess with an essentially cylindrical circumferential wall which is flush with the cylindrical first seat surface and the recess being dimensioned in such a way as to accommodate the end section and the radial first seal of the first closing element to form a seal during the opening motion before the second closing element opens.
PRIOR ART
[0002] EP 0 039 319 B1 discloses a double seat valve of the initially described type. The second closing element in this double seat valve is made as a seat disk whose seal acts purely axially on the assigned seat (seal with pressing engagement). The double seat valve, however, is not able to have its seats cleaned so that the prior art discloses no indications of flow engineering treatment of the seat cleaning flows generated when the seat is cleaned. Cleaning of the seats can be adequately defined as gap-wide exposure of the two seat surfaces of a double seat valve, separately and independently of one another, by partial lifting of the respective closing element, as a result of which cleaning liquid flows out of the valve housing part which is associated with the closing element on the path via the exposed seat into the leakage cavity.
[0003] A seat-cleanable double seat valve which allows cleaning of the respectively exposed seat by gap-wide opening of its seats is disclosed by DE 38 35 944 C2. Each of the three seals in this known double seat valve is a discrete seal, each seal having only a single function. The first seal in the first closing element is a strictly radially acting seal which slides in the first sealing surface made as a cylindrical envelope and seals there as a result of the provided pretensioning (seal with sliding engagement). The second seal in the second closing element acts on the second seat surface which is conical in shape so that the seal can act axially/radially here (seal with sliding/pressing engagement). The third seal, the so-called intermediate seal, develops its action when the first closing element in the opening lift comes into contact with the second closing element by way of this intermediate seal and, in the course of the continued opening motion, entrains the second closing element into the fully open position (seal in pressing engagement). The intermediate seal, in this case, is located in the front face which faces the leakage cavity on the second dependently driven closing element.
[0004] The seat cleanable double seat valve according to DE 38 35 944 C2 has two so-called seat cleaning positions, the first seat cleaning position being produced by the first partial lift of the first closing element which acts in the opposite direction to the opening lift. In the seat cleaning position of the first closing element (relative to the position of the drawing as shown in FIG. 3 , this is the lower closing element) the passage of a discharge bore which is connected to the first closing element and which is made as a pressure balance piston through the lower valve housing is at the same time exposed for purposes of cleaning of the assigned seal. The seat cleaning position of the second (upper) closing element is not further addressed in DE 38 35 944 C2; it takes place by the second partial lift which acts in the same direction as the opening lift. The respective amount of cleaning liquid in seat cleaning is limited by a more or less complex and often inadequate adjustment of the exposed gap between the respective seal and the associated seat surface.
[0005] For the double seat valve as shown in EP 0 039 319 B1, the seal in the first closing element has a double function; on the one hand it acts as a seat seal and, on the other hand, in the course of the opening motion and in the full open position of the double seat valve, also assumes the function of an intermediate seal in the double seat valve according to DE 38 35 944 C2.
[0006] A double seat valve which is limited solely to exposing the seat in the region of the associated closing element in seat cleaning and which, moreover, implements a connection of the leakage cavity to the vicinity of the double seat valve, which connection is generously dimensioned, the passage cross section of the connection corresponding roughly to the passage cross section of the greatest pipe width connected to the double seat valve, is described in company publication “Operating Instructions BAA D620-PMO.32, Double Seat Valve Type D 620 PMO” of Sümo Components GmbH, D-73469 Riesbürg. This double seat valve, due to its generous dimensioning of the connecting line between the leakage cavity and the exterior, is basically suited to preventing a pressure build-up in the leakage cavity in case of major seal defects.
[0007] To limit the amount of cleaning liquid in seat cleaning, providing throttle gaps which are located, for example, on the leakage space side and which are series-connected to the respectively exposed seat is known. A double seat valve, in this connection, is described in DE 196 08 792 A1. In this double seat valve the first seat cleaning position is produced by the first partial lift which acts in the opposite direction to the opening lift. Here, a cylindrical lug located on the first closing element on the leakage space side with the assigned cylindrical first seat surface forms the first throttle gap via which the amount of cleaning liquid which has been delivered from the adjacent first valve housing part can be limited. The seat cleaning position of the second closing element takes place by the second partial lift which acts in the same direction as the opening lift, in the partially open position the cylindrical lug located on the second closing element on the leakage space side forming with the assigned part of the connection opening a second throttle gap which quantitatively limits the second seat cleaning flow produced in this seat cleaning position. Since the two closing elements and the assigned cylindrical lugs have different diameters, the associated sections of the connection opening between the two valve housing parts are likewise different in diameter so that between these two diameters a transition surface arises.
[0008] This transition surface, which forms an obtuse, preferably, a right deflection angle with the section of larger diameter, results in that in the seat cleaning position of the first closing element, the first seat cleaning flow does not directly impact the second throttle gap and thus the seat region of the second closing element. Analogously, the second seat cleaning flow is prevented from acting directly on the first throttle gap and thus the seat region in the seat cleaning position of the second closing element.
[0009] In the seat and closing element configuration of the double seat valve according to EP 0 039 319 B1, such a transition surface and its action mechanism as a rule are unavailable so that the currently popular demand for preventing direct action on the seat regions in the course of cleaning the seat cannot be satisfied by this known double seat valve.
[0010] The requirements imposed on a seat-cleanable double seat valve in certain countries go beyond the aforementioned limitation of the amount of cleaning liquid and prevention of direct action on the seal region and are more extensive. Thus, for example, in the United States of America, it is required that for larger seal defects or even the loss of one of the two seat seals of the closing element in the closed position in the course of seat cleaning of the other closing element, no cleaning liquid may pass through via the respective seal defect or the seat region without a seat seal. Under these conditions, not only is the requirement for limiting the amount of cleaning liquid and avoiding direct admission into the seat regions in the course of seat cleaning imposed on this double seat valve, but also the requirement for discharge of the seat cleaning flow as much as possible without turbulence initially into the leakage cavity and from there into the exterior without the respectively closed seat region being exposed to a direct incident seat cleaning flow and/or its secondary flows or being acted upon in such as way as to raise the pressure.
[0011] Direct action is defined as any velocity component from the respective seat cleaning flow, which component is directed perpendicular to the walls that border the seat region. Specifically, it has been shown that any direct action in this respect leads to conversion of kinetic flow energy into static pressure. Depending on the impact angle of the flow on the flow-exposed wall surface or body surface there is a branching flow with a so-called “branching flow line”, the latter dividing the flow into two halves. The branching flow line itself runs against the so-called “stagnation point” so that the velocity is equal to zero at this point. The pressure increase as a result of this velocity stopping is also called the “impact pressure”. The above described pressure-increasing mechanisms, if they become active, generate a leakage flow via the respective throttle gap and the defective seat seal or one which is completely absent.
[0012] Direct impact of the seat cleaning flow on the surfaces which border the leakage cavity is therefore always counterproductive. With the exception of the double seat valve according to DE 196 08 792 A1, in the other known double seat valves described above, the first seat cleaning flow, which is generated by air striking the first closing element by the first partial lift, can more or less perpendicularly strike the front face boundary surface of the second closing element which holds the intermediate seal (DE 38 35 944 C2; double seat valve Type D 620 PMO) or the cylindrical recess (EP 0 039 319 B1). At the impact site this flow is diverted mainly toward the center of the leakage cavity. Furthermore, at the impact site a branching flow line arises whose branch facing the seat region can generate a vortex and an impact pressure there. The second seat cleaning flow which is generated by air striking the second closing element by the second partial lift more or less directly strikes the front face boundary surface of the first closing element, and, here as well, the part of the flow located between the branching flow line and the seat region can be supplied to the latter, forming impact pressure.
[0013] WO 2007/054 131 A1 and WO 2007/054 134 A1 already propose measures to ensure discharge of the seat cleaning flow into and out of the leakage cavity as much as possible without turbulence and to avoid pressure-increasing direct action on the seat surfaces. These measures, however, relate to a double seat valve with the features of DE 196 08 792 A1 which were briefly outlined above.
[0014] The object of this invention is to develop a double seat valve of the initially described type such that discharge of the seat cleaning flow into and out of the leakage cavity as much as possible without turbulence is ensured and pressure-increasing direct action on the seat areas is reliably avoided.
SUMMARY OF THE INVENTION
[0015] The object is achieved by a double seat valve with the features of claim 1 . Advantageous embodiments of the double seat valve whose seats can be cleaned according to the invention are described in the dependent claims.
[0016] To achieve the object underlying the invention, the first basic inventive concept consists in feeding the seat cleaning flow which emerges from the assigned gap between the seat seal and the seat surface in the respective seat cleaning as much as possible without turbulence and barriers into the leakage cavity and from there discharging it into the exterior in the same manner. This is achieved, on the one hand, by a new flow contour which steers and guides the seat cleaning flows in the leakage cavity. This new flow contour for seat cleaning of the first closing element which lies underneath provides for the first seat cleaning flow to follow the wall shape in the region of the first seat surface without detachment. Then, in the cylindrical recess of the second closing element, which recess is flush with the cylindrical first seat surface, smooth deflection of this first seat cleaning flow takes place so that the latter can travel into a discharge bore which is located centrally in the first closing element without colliding with the regions enclosing the leakage cavity, forming impact pressure. This is achieved in that the circumferential wall of the cylindrical recess on its end facing away from the first closing element undergoes transition into a rotationally symmetrical deflection surface and this deflection surface discharges in the front face of the recess which is oriented essentially perpendicular to the longitudinal axis of the second closing element.
[0017] Smooth deflection of the seat cleaning flow in the deflection surface is essential. This is achieved according to the invention in that, viewed in a vertical center section, the deflection surface runs without bends, a direction vector in the discharge point of the deflection surface under the aforementioned conditions being oriented toward the central discharge bore located in the closing element.
[0018] In flow guidance of the second seat cleaning flow generated by air striking the second closing element, it is essential that this flow detaches in a defined manner on a first circumferential edge which is formed by the second seat surface and the first end section of the first seat surface and is reliably routed tangentially past the surfaces which enclose the first closing element in the region of the leakage cavity. For this purpose, between the first circumferential edge and the pertinent regions of the first closing element there is a safety distance which under all possible circumstances of production engineering prevents impact in this connection.
[0019] This safety distance of the first closing element from the direction vector at the exit site of the second seat surface into the first end section of the first seat surface is advantageously dimensioned such that it is at least as large as the sum of all production tolerances of the components of the double seat valve which in the closed position of the first closing element determine its smallest axial distance to the second seat surface.
[0020] A second basic inventive concept consists in shifting the end position boundary, the desirable fixed stop of the second closing element which is not or cannot be accomplished in all cases (seat disks with axially acting seal in pressing engagement or seat disks with radially/axially acting seal in sliding/pressing engagement) in its closed position to the end of the seat, directly bordering the first seat surface. This is achieved according to the invention in that the second closing element in its closed position adjoins the second seat surface with a stop face which is located on its boundary surface adjacent to the second seal radially inside. Here, the stop face with the circumferential wall forms a second circumferential edge.
[0021] This measure eliminates the current gap which borders the leakage cavity between the second closing element and the valve housing, its generally being a metallic closure. At this point, in the course of seat cleaning of the closing element, cleaning liquid cannot reach the potentially defective seat seal or the seat seal which may not be entirely present any more by way of the metallically closed gap between the second closing element and the second seat surface.
[0022] Until now this defined closing of this critical gap was not provided in prior art double seat valves of the initially described type. In the implementation of the second basic inventive concept it is essential that the respective stop face on the second closing element and on the valve housing tightly and directly touch at the leakage cavity, completely circumferentially, as far as this is possible for solid or metallic contact.
[0023] The degrees of freedom in the configuration of the second closing element with respect to possible action mechanisms of the seat seal are not limited by the aforementioned stop face. Fundamentally, in this region there can be purely axially or radially/axially acting second seals.
[0024] It has furthermore been found to be favorable with respect to avoiding any formation of impact pressure if the first circumferential edge formed by the second seat surface and the end section of the first seat surface is rounded with the smallest possible second corner rounding. Ideally, a sharp-edge execution could be provided here, which, however, for reasons of production engineering and practical reasons (endangerment of the first seal) is not feasible.
[0025] To achieve a smooth transition of the radial first seal from the cylindrical first seat surface into the cylindrical circumferential wall of the recess in the second closing element it is furthermore proposed that the cylindrical circumferential wall ends in the second inlet slope and the latter with the stop face forms the second circumferential edge.
[0026] In order to prevent formation of impact pressure when the first seat cleaning flow enters the deflection surface in the second closing element, another proposal calls for the second circumferential edge formed by the stop face and the circumferential wall or the second inlet slope to be rounded with the smallest possible first corner rounding. A sharp-edged transition in this region is not favorable either here for reasons of production engineering and practical reasons, a relatively great radius of curvature is counterproductive and leads to unwanted formation of impact pressure.
[0027] In order to prevent the first seat cleaning flow after leaving the deflection surface from flowing against the front face of the recess to form impact pressure, it is furthermore provided that the deflection surface undercuts the front face by the axial undercutting distance. In this way the contour of the deflection surface in the region of its discharge point can be pitched by a second deflection angle relative to the front face of the cylindrical recess such that the first seat cleaning flow is easily deflected in the direction to the second closing element and then can follow the wall shape of the bordering front face of the cylindrical recess for purposes of its cleaning. It has been found to be advantageous if the second deflection angle is made in the range of 5 to 20 degrees, preferably with 15 degrees.
[0028] A flow result that is satisfactory in the same way is achieved according to another proposal by the contour being composed of a sequence of curved segments which on their respective transition sites each have a common tangent. Another embodiment calls for the contour to consist of a single section of continuously altered curvatures. Finally, it is also proposed that the contour is formed from a single section with a constant curvature.
[0029] In order to ensure discharge of the cleaning liquid without problems or disruption under all pressure and velocity conditions, it is provided that the discharge bore connects the leakage cavity to the vicinity of the double seat valve by way of several connecting bores which are distributed over the periphery, and that the front-face boundary of the first closing element which faces the leakage cavity has a chamfer which declines toward the discharge bore and which is circumferential on all sides.
[0030] In order to prevent the formation of vortices and impact pressure not only in the region of the above described seats surfaces of the double seat valve, it is advantageous if any internals and barriers in the remaining leakage cavity, as much as this is structurally possible, are omitted. In this respect, therefore, another proposal calls for the discharge bore to connect the leakage cavity to the vicinity of the double seat valve, and for the front-side boundary of the first closing element which faces the leakage cavity to have a chamfer which declines circumferentially on all sides toward the discharge bore. In this version a first shifting rod which is connected to the first closing element concentrically penetrates a second shifting rod which is made as a hollow rod and which is connected to the second closing element, continues floating through the discharge bore and is tightly connected on the end of the first closing element facing away from the second closing element to the first closing element via at least one essentially radially oriented traverse. In this way, the struts and other connecting means which are otherwise conventional in the region of the leakage cavity are avoided and shifted to the end which is relatively far away from the leakage cavity, where they can no longer have disruptive effects on flow guidance.
[0031] The aforementioned chamfer of the front face of the first closing element which is facing the leakage cavity is advantageously made as the envelope of a cone which is inclined relative to the base surface of the cone in the range of 10 to 20 degrees, preferably 15 degrees.
[0032] In this context, it is furthermore proposed that there are three traverses which are arranged distributed uniformly over the circumference securely on a section of the shifting rod, and which are tightly connected each radially outside to the circumferential ring and that the section of the shifting rod, the crosspieces and the ring form an integral welding part.
[0033] Here, it is furthermore advantageous if the welding part on the outside via the ring adjoins a pressure balance piston which borders the section of the discharge bore away from the leakage cavity, and on the inside adjoins the first shifting rod by way of a section of the shifting rod and if the ring in its inside diameter is enlarged relative to the diameter of the discharge bore with the interposition of a conically widening transition region such that the inside passage of the discharge bore is not narrowed by the traverses.
[0034] A second embodiment which relates to the second seat surface calls for the second seat surface to be made conical and to be tilted relative to the cylindrical recess by the seat angle, and for the second seal to seal axially/radially relative to the second seat surface in sliding/pressing engagement, the stop face adjoining the second seat surface according to the invention. The seat angle is made here in the range between 25 and 35 degrees, preferably with 30 degrees.
[0035] According to another configuration, it is proposed that the second seat surface is perpendicular to the longitudinal axis of the double seat valve, and that the second seal surface seals axially relative to the second seat surface in pressing engagement, here, the stop face also adjoining the second seat surface according to the invention.
[0036] Such solutions are possible with the advantages of an axially/ radially or a purely axially acting seal and a correspondingly interacting seat disk when the second seal is on the one hand made ductile and on the other can also undergo a change of shape with constant volume within the scope of its embedding such that the fixed contact of the second closing element with its stop face against the second seat surface, which contact is provided according to the invention, is ensured under all conditions, the fixed contact generally being a metallic contact.
[0037] In the above described first embodiment of the double seat valve according to the invention, the amount of cleaning liquid in seat cleaning is conventionally limited by adjusting the gap between the respective seat seal and the associated seat surface.
[0038] This invention within the scope of a second embodiment calls for limiting the amount of cleaning liquid in seat cleaning by means of a conventional throttle gap. For this purpose, it is provided that the end section provided on the first closing element on the leakage cavity side is made in the form of a cylindrical lug which with the first seat surface forms an annular first throttle gap. The second closing element, relative to its second seal, radially outside has a cylindrical circumferential contour, the latter forming an annular second throttle gap with an annular cylindrical recess in the connection opening on the side of the second closing element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] Embodiments of the proposed seat cleanable double seat valve according to the invention are shown in the drawings and are described below according to structure and function.
[0040] FIG. 1 shows in a longitudinal and vertical center section the seat-cleanable double seat valve according to the invention in a first embodiment, the closed position being shown,
[0041] FIG. 1 a shows in a longitudinal and vertical center section the double seat valve as shown in FIG. 1 , its being in its open position,
[0042] FIG. 2 shows in a longitudinal and vertical center section the double seat valve according to the invention in a second embodiment, the double seat valve being in its closed position and there being a limitation of the amount of cleaning liquid in both seat cleaning positions at this point by means of a throttle gap;
[0043] FIG. 2 a shows in a longitudinal and vertical center section the double seat valve shown in FIG. 2 in its open position,
[0044] FIG. 3 shows in a longitudinal section and extract an enlargement of the seat region of the double seat valve as shown in FIGS. 1 to 2 a ;
[0045] FIG. 4 shows schematically and enlarged the contour of the seat region for the first closing element and the bordering second seat surface for a double seat valve as shown in FIGS. 1 to 3 ;
[0046] FIG. 5 a shows in a perspective an integral welding part consisting of three traverses which tightly connect the section of the shifting rod to a ring, for connecting the first valve rod to a pressure balance piston which is located on the end of the first closing element away from the leakage cavity, and
[0047] FIG. 5 b shows in a vertical center section a composite construction of a first closing element and indirectly bordering pressure balance piston, welding part and first valve rod.
DETAILED DESCRIPTION
[0048] The double seat valve 1 according to the invention ( FIGS. 1 and 1 a ) in a first embodiment consists essentially of a valve housing 10 with a first and a second valve housing part 1 a and 1 b, two closing elements 3 and 4 which can move independently of one another with associated shifting rods 3 a and 4 a, and a seat ring 2 which produces a connection between the valve housing parts 1 a, 1 b by way of an inside connection opening 2 c.
[0049] The first closing element 3 (active closing element) which is made as a slide piston in the closed position of the double seat valve 1 is held to form a seal in the first seat surface 2 a which is formed by the connection opening 2 c and which is made as a cylindrical seat surface. For this purpose, in the slide piston 3 , there is a first seal 6 which interacts with the first seat surface 2 a exclusively by radial pretensioning (radial seal with sliding engagement). The second closing element 4 , which is made as a seat disk, in the closed position of the double seat valve 1 interacts with a second seat surface 2 b which is made perpendicular to the longitudinal axis of the double seat valve 1 on the top of the seat ring 2 . Sealing takes place by way of a second seal 7 which seals axially relative to the second seat surface 2 b in pressing engagement (seal with pressing engagement).
[0050] The two closing elements 3 , 4 both in the illustrated closed as well as open position between themselves form a leakage cavity 5 which is connected to the vicinity of the double seat valve 1 by way of a discharge bore 3 d which centrally penetrates a connecting part 3 b which is connected to the first closing element 3 and a pressure balance piston 3 c which continues on the connecting part.
[0051] Conventionally, the first shifting rod 3 a in the region of the first closing element 3 is securely connected to the latter by way of several webs which penetrate the discharge bore 3 d in a star shape and in the radial direction. In the present case, these webs are formed between connecting bores 3 d * ( FIG. 3 ) which penetrate the closing element 3 distributed over the circumference and connect the discharge bore 3 d to the leakage cavity 5 . Since these webs between the connecting bores 3 d * can have adverse reactive effects on the flow conditions and the flow pattern in the leakage cavity 5 , in the double seat valve 1 according to the invention it is preferably provided that these mechanically necessary connecting sites in the form of three traverses 3 e which are located distributed uniformly over the circumference are shifted a distance away from the leakage cavity 5 , preferably towards the end of the pressure balance piston 3 c facing away from the first closing element 3 ( FIGS. 1 , 1 a ). The fixed connection to the piston takes place by way of a circumferential ring 3 g to which the traverses 3 e are securely connected radially on the outside. Advantageously, the traverses 3 e, the ring 3 g, and shifting rod section 3 a are combined in an integral welding part 30 ( FIGS. 5 a , 1 ).
[0052] The second closing element 4 on its end facing the first closing element 3 has a recess 4 b with an essentially cylindrical circumferential wall 4 c which is flush with the cylindrical first seat surface 2 a ( FIGS. 1 to 3 ). This circumferential wall 4 c is dimensioned such that during the opening motion it accommodates the end section 3 * and the radial first seal 6 of the first closing element 3 , forming a seal, before the second closing element 4 opens.
[0053] The circumferential wall 4 c of the cylindrical recess 4 b in the second closing element 4 on its end facing away from the first closing element 3 undergoes transition into a rotationally symmetrical deflection surface 4 d (starting point of the contour (K)) ( FIGS. 3 , 1 ), and this deflection surface 4 d discharges in the front face 4 e of the recess 4 b which is oriented essentially perpendicular to the longitudinal axis of the second closing element 4 with a second deflection angle β. A second circumferential edge U 2 , which is formed by the circumferential wall 4 c and a closing element-side stop face 4 f, in the closed position of the second closing element 4 directly borders the first seat surface 2 a. Viewed in a vertical center section, the deflection surface 4 d has a contour K which runs without bends, a first section K 1 of the contour K which borders the circumferential wall 4 c continuing over other sections K 2 and K 3 ( FIG. 3 ) and the direction vector at the end point of the last section K 3 or Kn being oriented toward the discharge bore 3 d which is located centrally in the first closing element 3 or toward the connecting bores 3 d * without colliding with the first closing element 3 in the area of its regions enclosing the leakage cavity 5 .
[0054] So that a first seat cleaning flow R 1 which is routed via the gap between the first seal 6 and the first seat surface 2 a after the first partial lift T 1 of the first closing element 3 which is oriented downward relative to the position in the figure can be routed along the front face 4 e of the recess 4 b as tangentially as possible, without taking effect to form stagnation pressure ( FIG. 3 ), the deflection surface 4 d undercuts the front face 4 e by an axial undercut distance y. A front-side boundary of the first closing element 3 facing the leakage cavity 5 has an axial safety distance x from the direction vector at the exit site of the second seat surface 2 b into a first end section 2 g which is made on the first seat surface 2 a, the exit site being made in the form of a first circumferential edge U 1 .
[0055] In the open position of the double seat valve ( FIG. 1 a ), when a full opening lift H has been accomplished, it becomes clear that the first seal 6 which acts radially on the circumferential wall 4 c of the recess 4 b provides for reliable sealing of the two closing elements 3 , 4 between the valve housing parts 1 a, 1 b which are connected to one another by way of the connection opening 2 c on the one hand and the leakage cavity 5 on the other.
[0056] FIGS. 1 and 3 illustrate that the cylindrical circumferential wall 4 c on its end facing the first closing element 3 begins with a second inlet slope 4 h which is made preferably with a chamfer angle λ in the range from 5 to 15 degrees and here, in turn, preferably with 15 degrees and that the circumferential wall 4 c on its other end undergoes transition into the first section K 1 . The latter is angled radially to the outside at a first deflection angle ε relative to the circumferential wall 4 c, this first deflection angle ε being less than 15 degrees.
[0057] FIG. 3 furthermore illustrates that in the closed position of the double seat valve 1 the first and the second circumferential edge U 1 , U 2 end congruently at the leakage cavity 5 . Here, the first end section 2 g can be made as a conical section (first inlet slope) with exclusively curved or curved and straight contour elements, which is joined to the seat surface 2 a by the radius of curvature r 2 (see also FIGS. 4 and 1 a ) and opens toward the second closing element 4 . The first end section 2 g is tilted by an angle of pitch δ against the first seat surface 2 a. The angle of pitch δ is made in the range of 0 to 15 degrees, preferably in the range of 5 to 15 degrees and here, in turn, preferably with δ=15 degrees.
[0058] Further optimization of the first end section 2 g in the form of a further improved inlet slope is characterized as shown in FIG. 4 in that the first end section 2 g is formed by two envelopes of a cone which undergo transition into one another rounded with the radius of curvature r 2 , a second envelope of a cone 2 g . 2 which is joined directly to the first seat surface 2 a being tilted by a second angle of pitch δ 2 against the first seat surface 2 a and the other (the first) envelope of a cone 2 g . 1 being tilted by a first angle of pitch δ 1 against the first seat surface 2 a. The first angle of pitch δ 1 is made in the range of 7.5 to 15 degrees, preferably with δ 1 =15 degrees, and the second angle of pitch is made in the range of 5 to 10 degrees, preferably with δ 2 =7.5 degrees.
[0059] Furthermore, it is shown in FIGS. 1 to 3 that the front face of the first closing element 3 toward the discharge bore 3 d is provided with a declining conical chamfer 3 f, the latter preferably being made as the envelope of a cone and being inclined by an angle of inclination ζ relative to the base of the cone. This angle of inclination ζ is preferably made in the range of 10 to 20 degrees and here again preferably with ζ=15 degrees.
[0060] The first seat cleaning flow R 1 which emerges after completion of the first partial lift T 1 from the gap between the first seal 6 and the first seat surface 2 a ( FIG. 3 ) in the course of seat cleaning of the first closing element 3 first flows vertically along the first seat surface 2 a, without detaching follows the shape of the end section 3 * made as a first inlet slope 2 g or as envelopes of a cone 2 g . 2 , 2 g . 1 ( FIG. 4 ), bridges the inlet slope 4 h, follows the circumferential wall 4 c and the adjoining first section K 1 which is angled at the second deflection angle ε and without impact enters into the further shape of the deflection surface 4 d with its following sections K 2 and K 3 , is diverted there according to the contour K, leaves the third and last section K 3 (K 3 =Kn) with the second deflection angle β, is largely tangentially deposited on the front face 4 e and ultimately travels into the region of the discharge bore 3 d and the connecting bores 3 d *. So that the first seat cleaning flow R 1 cannot form an impact pressure on the second circumferential edge U 2 , the latter in the closed position of the second closing element 4 directly borders the first end section 2 g and is rounded with the smallest possible first corner rounding r 1 .
[0061] FIG. 3 details, in particular, the contour K which runs without bends. The first section K 1 and the third and last section K 3 (K 3 =Kn) which discharge from the front face 4 e are each made straight and these sections K 1 and K 3 are connected to one another by way of a second section K 2 which rounds the latter tangentially with a deflection radius as large as possible.
[0062] A further configuration of the deflection surface 4 d calls for the contour K to consist of a sequence of curved sections K 1 to Kn (e.g., arc of a circle, ellipses, parabolas, hyperbolas) which at their respective transition sites each have a common tangent. According to another configuration, the contour K is formed from a single section of continuously altered curvature (e.g., spirals or another curve shape which can be described as mathematically closed). The contour K according to another proposal is made with a single section with a constant curvature (e.g., a single arc of a circle with the required tangential entry and exit at the first deflection angle ε and the second deflection angle β.
[0063] In the double seat valve 1 according to the invention in the first embodiment the second seat surface 2 b is arranged perpendicular to the longitudinal axis of the double seat valve ( FIGS. 1 and 1 a , 3 ), the second seal 7 located in the second closing element 4 sealing axially relative to this second seat surface 2 b in pressing engagement. This solution is possible when the axially acting second seal 7 is ductile and a change of shape of constant volume is possible such that the first stop position of the second closing element 4 is ensured over the closing element-side chamfer surface 4 f in the region of the second seat surface 2 b which emerges in the first seat surface 2 a. The front face of the second closing element 4 which encloses the second seal 7 radially outside recedes a distance to ensure the above described defined fixed stop position by the stop face 4 f in the axial direction ( FIG. 3 ).
[0064] The second seat surface 2 b can also be made conical, the second seal 7 sealing axially/radially relative to the second seat surface 2 b in sliding/pressing engagement.
[0065] Seat cleaning of the second closing element 4 takes place ( FIG. 3 ) by the latter being struck by air by the second partial lift gap-wide from its associated second seat surface 2 b and cleaning liquid in the form of a second seat cleaning flow R 2 being routed from the bordering first valve housing part 1 b via the exposed second seat surface 2 b into the leakage cavity 5 . To ensure that the second seat cleaning flow R 2 is not diverted prematurely in the direction of the first closing element 3 , the first circumferential edge U 1 formed by the second seat surface 2 b and the first end section 2 g is rounded with the smallest possible second corner round r 3 ( FIG. 4 ), as a result of which a defined flow detachment site forms at this location. This measure ensures that the second seat cleaning flow R 2 is not directed at the seat region of the first seal 6 .
[0066] The first closing element 3 in seat cleaning of the second closing element 4 is axially positioned such that the second seat cleaning flow R 2 can flow unobstructed beyond the first closing element 3 . Depending on the given pressure conditions and under the influence of gravity in the arrangement of the double seat valve 1 as shown in the drawings, the liquid jet runs slightly parabolically so that the front face of the first closing element 3 with its chamfer 3 f is overflowed tangentially; this is desirable for reasons of cleaning. Thus flow guidance and positioning of the first closing element 3 even achieve suction of the seat region of the first seal 6 so that even with loss or significant damage of the first seal 6 , cleaning liquid R 2 cannot enter the adjacent first valve housing part 1 a.
[0067] The leakage space-side end of the gap between the second closing element 4 and the associated second seat surface 2 b is, for the most part, sealed tight by the above described fixed stop position of the second closing element 4 with its stop face 4 f on the second seat surface 2 b (as far as this is generally possible in solid against solid contact, preferably metal against metal). Cleaning liquid of the first seat cleaning flow R 1 can no longer enter the gap between the second closing element 4 and the associated second seat surface 2 b and thus the region of the second seal 7 . Even for a potentially seriously damaged or potentially completely removed second seal 7 therefore there is no longer any passage for cleaning liquid R 1 .
[0068] A second embodiment of the double seat valve 1 according to the invention is shown in FIG. 2 (closed position) and FIG. 2 a (open position). The end section 3 * provided on the first closing element 3 on the leakage space side is made in the form of a cylindrical first lug which with the associated section of the first seat surface 2 a forms an annular first throttle gap D 1 (see also FIG. 3 ). This first throttle gap D 1 takes effect when the first closing element 3 is pushed down by the first partial lift T 1 within the cylindrical first seat surface 2 a so far that the first seal 6 detaches from the latter and the first seat cleaning flow R 1 is routed out of the first valve housing part 1 a and is fed into the leakage cavity 5 .
[0069] The second closing element 4 , relative to its second seal 7 , radially outside has a cylindrical circumferential contour 4 *, formed by the cylindrical external shape of the second closing element 4 which, with an annular cylindrical recess 2 d in the connection opening 2 c on the side of the second closing element 4 , forms an annular second throttle gap D 2 ( FIG. 3 ). This second throttle gap D 2 takes effect when the second closing element 4 is raised by the second partial lift T 2 off the second seat surface 2 b so that the second seat cleaning flow R 2 is routed out of the second valve housing part 1 b and fed into the leakage cavity 5 .
[0070] FIG. 5 a shows the integral welding part 30 which is formed from the shifting rod section 3 a *, the three traverses 3 e, and the ring 3 g. The three traverses 3 e which are arranged uniformly distributed over the circumference of the shifting rod section 3 a * are connected securely to it. They are each connected radially outside likewise securely to the circumferential ring 3 g. The welding part 30 on the outside is welded by way of the ring 3 g to the pressure balance piston 3 c (see FIG. 5 b ) which borders the section of the discharge bore 3 d away from the leakage cavity and inside to the first shifting rod 3 a by way of the shifting rod section 3 a *. Here, the ring 3 g in its inside diameter is enlarged relative to the diameter of the discharge bore 3 d with the interposition of a conically widening transition region such that the inside passage of the discharge bore 3 d is not narrowed by the traverses 3 e.
REFERENCE NUMBER LIST OF THE ABBREVIATIONS USED
[0000]
1 double seat valve
10 valve housing
1 a first valve housing part
1 b second valve housing part
2 seat ring
2 a first seat surface (cylindrical seat surface)
2 b second seat surface (axial; axial/radial)
2 c connection opening
2 d annular recess
2 g first end section (first inlet slope)
2 g . 1 first envelope of a cone
2 g . 2 second envelope of a cone
3 first closing element (slide piston)
3 * end section (first cylindrical lug)
3 a first shifting rod
3 b connecting part
3 c pressure balance piston
3 d discharge bore
3 d * connecting bore
3 f chamfer
30 welding part
3 a * shifting rod section
3 e traverse
3 g ring
4 second closing element
4 * cylindrical circumferential contour
4 a second shifting rod
4 b recess
4 c circumferential wall
4 d deflection surface
4 e front face
4 f stop face (closing element-side)
4 h second inlet slope
5 leakage cavity
6 first seal (radial)
7 second seal (axial; radial; axial/radial)
r 1 first corner rounding (second closing element 4 )
r 2 radius of curvature (first inlet slope 2 g; 2 g . 1 ; 2 g . 2 )
r 3 second corner rounding (housing-side; seat ring 2 )
x axial safety distance
y axial undercutting distance
β second deflection angle
δ angle of pitch (of first inlet slope 2 g )
δ 1 first angle of pitch (first conical section 2 g . 1 )
δ 2 second angle of pitch (second conical section 2 g . 2 )
ε first deflection angle
ζ angle of inclination
λ chamfer angle (of second inlet slope 4 h )
D 1 first throttle gap
D 2 second throttle gap
H complete opening lift (completely open position)
K contour of deflection surface 4 b
K 1 first section (first straight line)
K 2 second section (curved contour)
K 3 third section (second straight line)
Kn last section
R 1 first seat cleaning flow
R 2 second seat cleaning flow
T 1 first partial lift (first partially open position/first seat cleaning position
T 2 second partial lift (second partially open position/second seat cleaning position
U 1 first circumferential edge
U 2 second circumferential edge
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The invention relates to a double-seat valve, the seats of which can be cleaned, which is improved compared to the prior art in that discharge of the seat cleaning flow into and out of the leakage cavity as much as possible without turbulence is ensured, and pressure-increasing direct action on the seat areas is reliably avoided. This is achieved among other things in that the double seat valve ( 1 ) has closing elements ( 3, 4 ) which can be transferred independently of one another by a respective partial lift gap-wide into the seat cleaning position for purposes of flushing their coaxial seat surfaces ( 2 a, 2 b ), the second closing element ( 4 ) by a second partial lift (T 2 ) which acts in the same direction as the opening motion and the first closing element ( 3 ) by a first partial lift (T 1 ) which acts in the direction opposite the opening motion travelling into its respective seat cleaning position, that the second closing element ( 4 ) in its closed position with a stop face ( 4 f ) which forms a second circumferential edge (U 2 ) with the circumferential wall ( 4 c; 4 h ) adjoins the second seat surface ( 2 b ), directly bordering the first seat surface ( 2 a ), that the circumferential wall ( 4 c ) on its end facing away from the first closing element ( 3 ) undergoes transition into a rotationally symmetrical deflection surface ( 4 d ) (starting point of the contour (K)) and this deflection surface ( 4 d ) discharges in the front face ( 4 e ) of the recess ( 4 b ) which is oriented essentially perpendicular to the longitudinal axis of the second closing element ( 4 ) (discharge point of the contour (K)), and that viewed in a vertical center section, the deflection surface ( 4 d ) has a contour (K) which runs without bends, and the direction vector at the discharge point of the deflection surface ( 4 d ) is oriented toward the center discharge bore ( 3 d; 3 d *) located in the first closing element ( 3 ) without colliding with the first closing element ( 3 ) in the area of its regions enclosing the leakage cavity ( 5 ) to form impact pressure ( FIG. 3 ).
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FIELD OF THE INVENTION
The invention relates to a process for the preparation of gasoline from hydrocarbon oils boiling above the gasoline range.
The preparation of gasoline from hydrocarbon oils boiling above the gasoline range catalytic cracking is employed on a large scale. Gasoline preparation by catalytic cracking is carried out by contacting the hydrocarbon oil to be cracked at an elevated temperature with a cracking catalyst. Catalytic cracking on a technical scale is generally conducted in a continuous process by using an apparatus substantially consisting of a vertically arranged cracking reactor and a catalyst regenerator. Hot regenerated catalyst coming from the regenerator is suspended in the oil to be cracked and the mixture is passed through the cracking reacting in upward direction.
Catalyst, which has become deactivated by carbon deposits is separated from the cracked product, stripped and then transferred to a regenerator, where carbon deposits are removed from the catalyst by burning them off. The cracked product is divided into a light fraction having a high C 3 and C 4 olefins content, a gasoline fraction, and several heavy fractions, such as a light cycle oil, a middle cycle oil, a heavy cycle oil and a slurry oil. In order to increase the yield of gasoline, one or more of the heavy product fractions can be recirculated to the cracking reactor, and the C 3 and C 4 olefins present in the light fraction can be converted by alkylation with isobutane into alkylate gasoline.
In catalytic cracking on a technical scale it is an objective to have the amount of heat which is released in the regenerator during the burning off of coke deposits from the catalyst crrespond substantially with the amount of heat required in the cracking reactor, so that the process can be conducted without additional heating or cooling devices having to be installed. In determining reaction conditions under which the catalytic cracking process should be carried out, the reactor carbon requirement of the cracking unit and the Conradson carbon test value of the feed play an important role. The term "reactor carbon requirement" of the cracking unit (R as %w, calculated on catalyst) is used to designate the quantity of carbon that must be deposited on the catalyst in the cracking unit in order to result in the correct amount of heat being released in the regenerator, which in turn corresponds substantially to the amount of heat required in the cracking reactor. For a given feed the amount of carbon deposited in the cracking reactor on the catalyst will generally be larger as the cracking is carried out under more sever conditions. A feed with a higher Conradson carbon test value (C as %w, calculated on feed) during cracking of that feed in the cracking unit under given conditions will generally lead to higher amounts of carbon being deposited on the catalyst in the cracking reactor.
BRIEF DESCRIPTION OF THE INVENTION
Succinctly, the instant invention relates to a process for the preparation of gasoline, in which a mixture of two hydrocarbon oils, both of which boil above the gasoline range, are subjected to catalytic cracking at a temperature between 475° and 550° C. in a catalytic cracking unit having a value for R between 3 and 8%w, in which one hydrocarbon oil has a value for C that the quotient C/R is higher than 0.8, and in which the other hydrocarbon oil has a value for C that the quotient C/R is lower than 0.2, and in which the latter hydrocarbon oil also has a value for N of less than 150 ppmw and a value for T of less than 3%w.
OBJECTS AND EMBODIMENTS
A specific embodiment of this invention resides in a process for the preparation of a hydrocarbon product boiling in the gasoline range from a mixture of hydrocarbon oils boiling above the gasoline range which comprises catalytically cracking said mixture of said hydrocarbon oils in a catalytic cracking unit having a reactor carbon requirement (R) between 3 and 8%w, said mixture composed of: (a) a first hydrocarbon oil having a Conradson carbon test value (C 1 ) in percent weight (%w) such that the quotient C 1 /R is higher than 0.8 and (2) a second hydrocarbon oil having a Conradson carbon test value (C 2 ) such that the quotient C 2 /R is lower than 0.2 and wherein said second hydrocarbon oil has a basic nitrogen content (N) of less than 150 ppmw and a tetra + aromatics content (T) of less than 3%w.
A more narrow embodiment of this invention resides in the above process wherein the first hydrocarbon oil and the second hydrocarbon oil have respective values for C 1 and C 2 such that the difference between quotients C 1 /R and C 2 /R is greater than 8.
Another embodiment of this invention resides in the broader invention above depicted wherein the first hydrocarbon oil has a value for C 1 such that the quotient C 1 /R is higher than 0.9 and the second hydrocarbon oil has a value for C 2 such that the quotient C 2 /R is lower than 0.1.
Another embodiment of this invention resides in a process as above depicted with a more narrow definition in that the second hydrocarbon oil has a value for C 2 such that the quotient C 2 /R is lower than 0.2, and the hydrocarbon oil has a value for N of less than 100 ppmw and a value for T of less than 2%w.
Another embodiment of this invention resides in a process for the catalytic conversion of a hydrocarbonaceous feed mixture boiling above the gasoline boiling range in the presence of a cracking conversion catalyst comprising a zeolite in a cracking reactor having a reactor carbon requirement (R) between 3 and 8%w to a hydrocarbon product boiling in the range of C 5 to 221° C., the improvement comprising the selection of the feed admixture in accordance with:
(a) 30 parts to 70 parts of a first hydrocarbon oil having a Conradson carbon test value (C 1 ) in percent weight (%w) such that the quotient C 1 /R is higher than 0.8 and
(b) 70 parts to 30 parts of a second hydrocarbon oil having a Conradson carbon test value (C 2 ) in percent weight (%w) such that the quotient C 2 /R is lower than 0.2 and having a basic nitrogen content (N) of less than 150 ppmw and a tetra + aromatics content (T) of less than 3%w.
DETAILED DESCRIPTION OF INVENTION
A convenient criterion for assessing the suitability of feeds for a catalytic cracking unit in which cracking is carried out under conditions that a quantity of carbon, which in the cracking reactor is deposited on the catalyst corresponds to R, is the quotient C/R. Generally, a feed will yield more gasoline as the quotient C/R is lower.
During an investigation into the preparation of gasoline by catalytic cracking of hydrocarbon oils boiling above the gasoline range, at temperatures between 475° and 550° C., in a catalytic cracking unit having a value for R between 3 and 8%w, it has now surprisingly been found that the cracking of a specific mixture of two hydrocarbon oils results in a gasoline yield which is much higher than expected under the assumption of linear mixing. In order to attain said increase in gasoline yield, one of the two mixing components is chosen from the group formed by hydrocarbon oils having a C/R>0.8, while the other mixing component should be chosen from the group formed by hydrocarbon oils having a C/R<0.2 and which in addition has a basic nitrogen content (N) of less than 150 ppmw and a tetra + aromatics content (T) of less than 3%w. It has been unexpectedly found that if the two mixing components are well chosen, 20% more gasoline can be prepared from the resultant specific mixture than expected to date under the assumptions of linear mixing.
In the process according to the instant invention the two mixing components have a C value such that the difference between the quotients C/R of the mixing components is bigger than 0.6. Preferably, the mixing components have a C value such that said difference is bigger than 0.8. It is preferred that one of the two mixing components has a C value such that the quotient C/R is higher than 0.9, whereas the other mixing component preferably has a C value such that the quotient C/R is lower than 0.1. As for the values for N and T of the mixing component having a C value such that the quotient C/R is lower than 0.2, preference is given to hydrocarbon oils having an N value of less than 100 ppmw and a T value of less than 2%w.
In the process according to this invention, one preferred mixing component has a C value such that when the quotient C/R is higher than 0.8, such as a residue obtained via the distillation of a crude mineral oil, which residue has optionally been subjected to a deasphalting treatment. Residues obtained via atmospheric distillation of a crude mineral oil and distillation residues obtained in the vacuum distillation of an atmospheric residue of a crude mineral oil are eligible as mixing components. Special preference is however given to atmospheric distillation residues. A preferred mixing component with a C value such that the quotient C/R is lower than 0.2 is a heavy distillate obtained via the distillation of a crude mineral oil, which distillate has optionally been subjected to a catalytic hydrotreatment. Heavy distillates obtained via atmospheric distillation of a crude mineral oil and heavy distillates obtained via vacuum distillation of an atmospheric residue of a crude mineral oil are eligible as mixing components. Special preference is given to hydrocarbon oils which have been prepared by applying a catalytic hydrotreatment to a heavy distillate obtained via vacuum distillaion of an atmospheric distillation residue of a crude mineral oil. A vacuum distillate subjected to catalytic hydrotreatment preferably has a C value such that the quotient C/R is lower than 0.4 and a value for N of more than 300 ppmw and a value for T of more than 2.9%w. The catalytic hydrotreatment of the vacuum distillate is preferably carried out at a temperature of 275°-450° C., and in particular at a temperature of 300°-425° C., a hydrogen pressure of 25-80 bar and in particular a hydrogen pressure of 30-70 bar, a space velocity of 0.1-5 1.1 -1 .h -1 and in particular a space velocity of 0.2-3 1.1 -1 .h -1 and H 2 /feed ratio of 100-2000 Nl.kg -1 and in particular a H 2 /feed ratio of 200-1500 Nl.kg -1 . A preferred catalyst for hydrotreating the vacuum distillate is a sulphided catalyst comprising nickel and/or cobalt together with molybdenum and/or tungsten supported on a carried chosen from alumina, silica, or silica-alumina as carrier.
The weight ratio of the two components in the specified mixture which is catalytically cracked according to this invention may vary within wide ranges. Preferably mixtures are used for which the weight ratio of the two components lies between 30:70 and 70:30 and in particular between 40:60 and 60:40.
The catalytic cracking according to the invention is preferably carried out at a temperature of 485°-540° C. and in particular at a temperature of 495°-530° C., a pressure of 1-10 bar and in particular a pressure of 1.5-7.5 bar, a space velocity of 0.25-4 kg.kg -1 .h -1 and in particular a space velocity of 0.5-2.5 kg.kg -1 .h -1 and a catalyst renewal rate of 0.1-5 and in particular a catalyst renewal ratio of 0.2-2, kg of catalyst per 1000 kg of feed. In the catalytic cracking preference is given to the use of a zeolitic catalyst.
The invention is now illustrated with the aid of the following.
ILLUSTRATIVE EMBODIMENT
In order to prepare gasoline with a boiling range of C 5 -221° C., nine experiments (Experiments 1-9) were carried out in a catalytic cracking unit having a R value of 5%w. Three feeds defined below were used in the cracking: Feed 1, Feed 2 and a mixture of Feed 1 and 2.
Feed 1=a 370° C. + residue obtained via atmospheric distillation of a crude mineral oil with the properties shown in Table I.
Feed 2=a 370° C. + residue obtained via atmospheric distillation was hydrotreated at a temperature of 380° C., a hydrogen pressure of 54 bar, a space velocity of 0.9 g.g -1 h -1 and a H 2 /feed ratio of 400N l-kg -1 over a Ni/Mo/Al 2 O 3 catalyst. The physical properties of Feed 2 and the pre-hydrotreated Feed 2 precursor are shown in Table 1.
TABLE 1______________________________________ Feed 2 Precursor Feed 2 (before (afterValue Feed 1 hydrotreatment) hydrotreatment)______________________________________T 5.32% w 4.65% w 2.55% wN 731 ppm w 461 ppm w 30 ppm wC 5.1% w 1.1% w 0.4% wC/R 1.02 0.22 0.08______________________________________
Both Feed 1 (Experiment 1) and Feed 2 (Experiment 2) were individually cracked in addition to mixtures of Feeds 1 and 2 (Experiments 2 through 8). The results of these tests are shown in Table 2 as well as the space velocities in each applicable experiment. The actual yield of gasoline is shown in Table 2 along with the expected yield calculated by the formula: ##EQU1## The gain in gasoline yield is expressed as ##EQU2##
TABLE 2__________________________________________________________________________ Gasoline yield, % w on feedFeed Space Calculated under Gain inExperiment Feed 1 Feed 2 velocity Experimentally the assumption gasoline yield,No. gew. % gew. % kg · kg.sup.-1 · h.sup.-1 Found of linear mixing %__________________________________________________________________________1 100 -- 9.2 31.1 -- --2 80 20 6.4 39.9 34.7 153 70 30 5.5 43.4 36.5 194 60 40 4.8 46.1 38.3 205 50 50 4.2 48.1 40.1 206 40 60 3.7 49.3 41.8 187 30 70 3.4 49.8 43.6 148 20 80 3.0 49.7 45.4 99 -- 100 2.5 49.0 -- --__________________________________________________________________________
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This invention concerns a process for the preparation of a gasoline boiling hydrocarbon from a mixture of hydrocarbons specifically defined. The hydrocarbon feedstock is a mixture of two hydrocarbon oils with the first hydrocarbon oil having a Conradson carbon test value C 1 and % w such that the quotient of C 1 /R is higher than 0.8 and a second hydrocarbon oil having a Conradson carbon test number C 2 such that the quotient C 2 /R is lower than 0.2 wherein R is equal to the reactor carbon requirement for the particular catalytic cracking unit and is between 3 and 8 percent by weight.
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TECHNICAL FIELD
The invention relates in general to refrigeration systems, and more specifically to refrigerant distribution techniques in refrigeration systems.
BACKGROUND ART
When the evaporator coil of a refrigeration system is operating at or near full load, the evaporator coil is almost fully flooded with refrigerant. When the evaporator coil is almost fully flooded, the temperature of the coil across its length will be very uniform, and thus air flowing across the evaporator coil will have a uniform discharge temperature across the coil length. This is very important in transport refrigeration systems, as perishables have a shelf life dependent upon the ability of the transport refrigeration system to maintain a desired set point temperature. Only a few degrees temperature difference may deleteriously affect the shelf life of a perishable product in the cargo space of a truck, trailer, container, and the like.
In an effort to maintain the temperature of the served cargo space as closely as possible to set point, and thus obtain the shelf life advantage, suction line modulation is being increasingly used by refrigeration system control algorithms to reduce the mass flow of refrigerant when the sensed temperature is close to the predetermined set point temperature For example, U.S. Pat. No. 4,899,549, which is assigned to the same assignee as the present application, discloses a transport refrigeration system which has a suction line modulation valve, with the associated refrigeration control providing suction line modulation in cooling and heating cycles above and below set point, respectively.
While suction line modulation enables a sensed temperature to be held closer to set point, controlling the cooling capacity of a refrigeration system by reducing the refrigerant mass flow may result in only a small portion of the evaporator coil being flooded with refrigerant when extensive capacity reduction is required. As a result, the air temperature along the length of the evaporator coil may not be uniform, i.e., the evaporator coil will be colder at the refrigerant distribution end of the evaporator coil than at the opposite end.
Accordingly, it would be desirable, and it is an object of the invention, to be able to provide a more uniform temperature of air flow across, i.e., transverse to, the length dimension of an evaporator coil, especially with refrigeration systems which may only partially flood an evaporator coil with refrigerant during their operation, such as those which utilize suction line modulation to reduce cooling and heating capacity near set point.
SUMMARY OF THE INVENTION
Briefly, the present invention is a refrigeration system which includes a refrigerant circuit having an evaporator coil defined by predetermined length and width dimensions, with the length dimension being terminated by first and second longitudinal ends. Air delivery means in the form of fans or blowers draw air from a served space, pass it over the evaporator coil, and return the conditioned air to the served space.
The evaporator coil has a plurality of parallel refrigerant circuits. Each refrigerant circuit is initiated by a coil tube having an opening at the first longitudinal end of the evaporator coil, with the coil tube extending to the second longitudinal end of the evaporator coil. A refrigerant distributor is provided which has an inlet, and a plurality of outlets defined by a plurality of distributor tubes. The distributor tubes extend into the openings of the refrigerant circuit initiating coil tubes for at least first and second different predetermined dimensions. The refrigerant is thus expanded at different locations across the length of the evaporator coil, providing a more uniform cooling of the evaporator coil across its length, even when the refrigeration system control is providing a large reduction in refrigeration capacity. With a more uniform coil temperature, the air flowing across the evaporator coil will also have a more uniform temperature, measured from one end of the coil to the other.
In a preferred embodiment of the invention, the plurality of refrigerant circuits are laterally spaced apart along the width dimension of the evaporator coil, with the distributor tubes which extend into their associated coil tubes for the first predetermined dimension alternating with distributor tubes which extend into their associated hairpin tubes for the second predetermined dimension. The first predetermined dimension is preferably a relatively short dimension, such that the ends of the distributor tubes start substantially at the first longitudinal end of the evaporator coil. The second predetermined dimension is preferably a relatively long dimension, such that the ends of the distributor tubes extend into the associated coil tubes for at least one third of the length of the evaporator coil. Of course, instead of only first and second predetermined different dimensions, a larger plurality of different dimensions may be used, as desired.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will become more apparent by reading the following detailed description in conjunction with the drawings, which are shown by way of example only, wherein:
FIG. 1 is a partially block and partially schematic diagram of a refrigeration system which may be constructed according to the teachings of the invention;
FIG. 2 is an elevational view of a typical evaporator coil construction, which may utilize the teachings of the invention;
FIG. 3 is an end elevational view of the evaporator coil shown in FIG. 2;
FIG. 4 is a fragmentary plan view of a plurality of evaporator coil circuits, illustrating almost complete flooding of the circuits with refrigerant, such as when the evaporator coil is substantially fully loaded;
FIG. 5 is a fragmentary plan view of a plurality of evaporator coil circuits, similar to FIG. 4, except illustrating the partial flooding which occurs when the refrigerant capacity is reduced, such as by reducing the mass flow of refrigerant with a suction line modulation valve; and
FIG. 6 is a fragmentary plan view of a plurality of evaporator coil circuits, illustrating partial flooding similar to FIG. 5, except with an evaporator coil constructed according to the teachings of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings, and to FIG. 1 in particular, there is shown in schematic form a refrigeration system 10, such as the transport refrigeration system set forth in the hereinbefore mentioned U.S. Pat. No. 4,899,549. Refrigeration system 10 includes a compressor 12 driven by a suitable prime mover 13, such as an internal combustion engine, or an electric motor. Compressor 12 includes discharge and suction ports D and S, respectively, with the discharge port D being connected to a hot gas line 14. The hot gas line 14 is connected into a selected one of first and second refrigerant circuits 16 or 18, respectively, via a circuit selecting valve arrangement, such as a three-way valve 20, as illustrated, or two separate valves. Three-way valve 20 is normally in a position which selects the first refrigerant circuit 16 A pilot solenoid valve PS, when energized by refrigeration control 22, connects valve 20 to the low pressure side of compressor 12, to cause valve 20 to switch and connect hot gas line 14 to the second refrigerant circuit 18.
The first refrigerant circuit 16 includes a hot gas line 24; a condenser 26; a check valve 28; a receiver 30; a liquid line 32; an expansion valve 34, which typically includes a thermal control bulb 35 and an equalizer line (not shown); a refrigerant distributor 36; an evaporator 38; a suction line modulation valve 40; an accumulator 42; and a suction line 44 which returns refrigerant to the suction port S of compressor 12. The control bulb 35 of the expansion valve 34 is disposed in heat exchange relation with an output line 45 of evaporator 38.
An evaporator blower or fan arrangement 46 draws air, indicated by arrows 47, from a served space 48, such as the cargo space of a truck, trailer, or container. The return air 47 is passed in heat exchange relation across evaporator coil 38, and the resulting conditioned air, indicated by arrows 49, is returned to, or discharged into, the served space 48. The first refrigerant circuit results in cooling the evaporator coil, which removes heat from the air 47, cooling the served space 48.
The heat absorbed by the refrigerant in evaporator 38 evaporates the refrigerant, and this heat is removed from the refrigerant in condenser 26, as the refrigerant changes back to a liquid state. A condenser fan or blower arrangement 50 draws ambient air, indicated by arrows 51, and forces it to flow in heat exchange relation with condenser 26, discharging the heated air, indicated by arrows 53, back into the atmosphere.
When the served space 48 requires heat to maintain the predetermined set point temperature, as sensed by a return air temperature sensor 54, and/or by a discharge air temperature sensor (not shown), and also when evaporator coil 38 requires defrosting, control 22 energizes pilot solenoid PS, selecting the second refrigerant circuit 18. The second refrigerant circuit includes a hot gas line 52 which is connected directly to the refrigerant distributor 36, introducing hot refrigerant gas into the evaporator coil 38. During a heating cycle, the evaporator coil 38 adds heat to the air 47, with the warmed air 49 being discharged into the served space 48. During a defrost cycle, no air is discharged into served space 48, with the hot refrigerant warming the evaporator coil to remove any frost and ice which may have built up since the last defrost operation.
FIG. 2 is an elevational view of evaporator coil 38 and distributor 36, and FIG. 3 is a right-hand end elevational view, when viewing FIG. 2. Evaporator coil 38 is an elongated structure, having a length dimension indicated at 56 in FIG. 2, and a width dimension indicated at 58 in FIG. 3. Evaporator coil 38 has first and second longitudinal ends 60 and 62, respectively, and a longitudinal axis 64 which extends between its ends. Evaporator coil 38 has a plurality of metallic coil tubes 66 which extend between ends 60 and 62, with the coil tubes 66, which may be hairpin tubes, being supported by first and second end header plates 68 and 70, respectively, and a center header plate 72. The coil tubes 66, which are disposed in heat exchange relation with a plurality of metallic fins 74, are divided into a plurality of separate parallel refrigerant circuits, such as 13 in the example illustrated in FIGS. 2 and 3. Each refrigerant circuit, which may be constructed of a plurality of coil tubes 66 interconnected by end bends 76, includes a refrigerant circuit initiating coil tube 66 having ends defining inlet openings at the first longitudinal end 60 of evaporator coil 38, such as the tube ends indicated at 78 in FIG. 3. The plurality of refrigerant circuits are laterally spaced across the width dimension 58 of the evaporator coil 38. Each of the refrigerant circuits has a refrigerant circuit terminating tube 66 which discharges into a suction header 79, which in turn is connected to the evaporator output line 45.
The refrigerant distributor 36 has a single metallic inlet line 80 and a plurality of metallic distributor tubes 82, e.g., one for each of the 13 refrigerant circuits of the exemplary embodiment. As illustrated in FIG. 3, each of the distributor tubes 82 extends into an opening defined by the ends 78 of the refrigerant circuit initiating tubes 66, with solder joints 84, shown in FIGS. 4, 5 and 6, sealing the opening at ends 78. In the prior art, as illustrated in FIGS. 4 and 5, the ends 86 of the distributor tubes 82 extend for a like short dimension into the openings defined by the coil tube ends 78, with this predetermined dimension being just long enough to insure that good solder joints 84 may be achieved between the two tubes 66 and 82.
FIGS. 4, 5 and 6 are fragmentary plan views which illustrate the refrigerant circuit initiating coil tubes 66 of the first four refrigerant circuits of evaporator coil 38.
FIG. 4 illustrates evaporator coil 38 when refrigeration system 10 is operating at or near full capacity. When refrigeration system 10 is operating at or near full load, with modulation valve 40 wide open, evaporator coil 38 is almost fully flooded with refrigerant 88, with the refrigerant 88 being illustrated in FIGS. 4, 5 and 6 with the plurality of small dots. It will be noted that in FIG. 4 the refrigerant 88 extends completely across the length of the coil tubes 66, from the first longitudinal end 60 of evaporator coil 38 to the second longitudinal end 62. This condition uniformly cools evaporator coil 38 from end to end, and the temperature of the discharge air 49 is very uniform across the coil length 56, i.e., the temperature of air 49 leaving evaporator coil 38 near its first longitudinal end is substantially the same as the temperature of air 49 leaving evaporator coil 38 near its second longitudinal end.
When modulation valve 40 is operated by refrigeration control 22 to reduce the mass flow of refrigerant when the temperature of the served space 48, such as sensed by the return air temperature sensor 54, is near set point, only a small portion of evaporator coil 38 may be flooded with refrigerant 88, as indicated in FIG. 5. The evaporator coil 38 will then be colder at the first longitudinal end 60, where the distributor tubes 82 introduce refrigerant into the evaporator coil 38, than at the second end, and the discharge air 49 leaving evaporator coil 38 will have a similar non-uniform temperature across the coil length 56. In other words, the discharge air 49 will be colder near the first longitudinal end than near the second longitudinal end.
The present invention improves the evaporator coil temperature uniformity across its length 56, and thus the air temperature is more uniform from one end of the evaporator coil 38 to the other, by extending some of the distributor tubes 82 further into the coil tubes 66 than others. The inside diameter (ID) of the distributor tubes 82 is much less than the ID of the coil tubes 66, preventing any significant expansion of the refrigerant 88 until it reaches the end 86 of the distributor tube. Thus, the cooling effect of the refrigerant 88 starts at the ends 86 of the plurality of distributor tubes 82. By varying the location of the ends 86 along the length 56 of evaporator coil 38, the condition illustrated in FIG. 6 may be obtained, wherein some of the coil tubes 66 are flooded with refrigerant 88 starting at longitudinal end 60 of evaporator coil 38 and extending to approximately the center of the coil 38, and the remaining coil tubes 66 are flooded with refrigerant 88 starting near the center of coil 38 and extending to the second longitudinal end 62. Thus, the discharge air 49 will have a substantially uniform temperature along the entire length 56 of the evaporator coil 38.
In verifing the benefit of the distributor tube arrangement shown in FIG. 6, an evaporator coil 38 having a length dimension of 64 inches (1625 mm) and a width dimension of 13.4 inches (340 mm) was constructed of hairpin coil tubes 66 having a tube outside diameter (OD) of 0.375 inch (9.5 mm), with a wall thickness of 0.016 inch (0.406 mm). Thirteen parallel refrigerant circuits were used, as in the exemplary embodiment, with 6 coil tubes per circuit. A total of 376 fins 74 were used, providing a density of six fins per inch (2.4 fins per cm). The distributor tubes 82 had an OD of 0.1875 inch (4.76 mm) and a wall thickness of 0.030 inch (0.76 mm). Thus, the ID of the coil tubes 66 has about 7.5 times greater cross sectional flow area than the distributor tubes 82.
The ends 86 of the distributor tubes 82 were inserted into the ends 78 of the coil tubes 66 for first and second predetermined dimensions, indicated at 90 and 92 in FIG. 6. The first predetermined dimension 90 was just long enough to insure a good solder joint 84, such as about 1 inch (25.4 mm), and the second predetermined dimension was 20 inches (508 mm). The first and second predetermined dimensions 90 and 92 were alternated across the coil width 58, with the odd numbered circuits 1, 3, 5, 7, 9, 11 and 13 having the first dimension 90 and the even numbered circuits 2, 4, 6, 8, 10 and 12 having the second dimension 92.
An evaporator coil was also constructed according to the teachings of the prior art, as illustrated in FIGS. 4 and 5, wherein the first dimension 90 was used for all distributor tube insertions. Except for this change, the two evaporator coils were of like construction. Operating each evaporator coil under the same mass flows, with the modulation valve 40 restricting the mass flow to the same extent, provided a temperature differential across the coil length 56 of 3 degrees F. (1.67 degrees C.) using the prior art construction, while the evaporator coil constructed according to the teachings of the invention had a temperature differential across the coil length 56 of only 1.5 degrees F. (0.83 degrees C.), a temperature distribution improvement of 50%. This is a very significant improvement, especially in transport refrigeration systems which must closely maintain predetermined set point temperatures in their cargo spaces, to preserve and increase the shelf life of perishable products, such as foods and flowers.
The invention automatically provides a more uniform temperature across the evaporator coil as the load on the evaporator coil drops, without requiring any additional electrical control, any additional distributors, any additional solenoid valves, and without requiring any additional tapping of refrigerant circuits. In addition to achieving the hereinbefore described advantages without any additional hardware or control, the invention adds insignificantly to the manufacturing time or cost, as the soldering operation between the hairpin tubes and distributor tubes is the same as utilized in prior art evaporator coil construction. The fact that first portion of some refrigerant circuits, i.e., the circuits in which the distributor tubes 82 are inserted in the coil tubes 66 for the greater distance 92, insignificantly affects operation of the evaporator coil at higher loads, as each refrigerant circuit has a plurality of coil tubes 66. Thus, air temperature uniformity is not deleteriously affected at higher loads, and the reduction in capacity of the evaporator coil 38 is slight, e.g., less than 3% in the example in which each refrigerant circuit has six coil tubes.
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A refrigeration distribution arrangement which improves the uniformity of coil temperature distribution along the length of an evaporator coil. The distribution arrangement is particularly beneficial when an evaporator coil is operating partially flooded with refrigerant, such as when refrigeration capacity is being reduced with a suction line modulation valve. Distributor tubes from a refrigerant distributor are inserted for at least first and second different dimensions into coil tubes which initiate a plurality of refrigerant circuits in the evaporator coil. In an exemplary embodiment, the first dimension is a relatively short dimension, and the second dimension is a relatively long dimension, such as about one-third of the coil length. The refrigerant thus expands at different locations across the coil length, initiating coil cooling at different coil locations. The discharge temperature of air (flowing across the evaporator coil into a served space is thus more uniform across the coil length.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 219,966 filed Jan. 24, 1972 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to pressure boosters for fluid distribution circuits and to hydraulic distribution circuits incorporating such boosters. More specifically, this invention relates to the enhancement of the flow and pressure characteristics of fluid distribution circuits. Accordingly, the general objects of the present invention are to provide novel and improved apparatus and methods of such character.
2. Description of the Prior Art
While not limited thereto in its utility, the present invention is particularly well suited to use in or as a fluid supply circuit connected to a general water distribution system wherein the flow demands can vary between rather extreme limits. An example of such a system would be a complex of living units where it is necessary to satisfy peak demands for water while simultaneously preventing the pressure from dropping below a predetermined value. Similar problems are presented in, and the present invention is also applicable to, air distribution systems such as ventilation circuits incorporating fans or blowers.
Problems of the type alluded to above have, in the case of hydraulic distribution circuits, previously been solved through the use of hydro-pneumatic pressure booster systems wherein one or more centrifugal pumps were controlled in an on-off fashion. Such prior art systems typically employ an elastic cushion, defined by a pressurized vessel containing a quantity of air, and the volume variations between two predetermined pressures are measured and used to determine the operating cycle of the pump or pumps. Such prior art hydro-pneumatic pressure booster systems have been characterized by relatively high maintenance costs due, in part, to the necessity of periodically reinflating the air cushion; such reinflation being necessitated by micro-leaks or by natural dissolution of the air in water.
In the interest of reducing the size and complexity of pressure booster systems in hydraulic distribution circuits, and also in reducing maintenance requirements and power consumption, it has been proposed to employ permanently operating pressure maintenance pumps. The use of such continuously operating pumps enables elimination of the pressurized vessel since the pump pressure head is added to the pressure of the system. At first glance this would appear to insure adequate pressure in the fluid distribution circuit. However, systems employing continuously operating pressure maintenance pumps have encountered difficulties in insuring peak flows. The provision of grossly oversized pumps to insure adequate peak flows is not an economically feasible solution to these difficulties.
Comparative complex control systems employing both continuously and intermittently operated booster pumps have also been proposed in hydraulic distribution circuits of the type being discussed for purposes of explanation. In such systems there has typically been a functional disparity in size between the continuously operating units and the peak load supplying units and such functional disparities have imposed additional complications on the systems.
A further prior art attempts at solving peak flow problems in hydraulic circuits has envisioned varying the speed of the booster pumps either continuously or in stages. This approach has, however, resulted in extremely complex and expensive systems. This complexity results from the fact that the flow delivered by an electric motor drive centrifugal pump varies with speed thereby making it difficult to multiply the flow provided by a group of such pumps by three or four times as may be encountered during peak load periods. Additionally, adding to system complexity and thus lack of reliability, is the fact that pump compression level varies with the square of pump speed. As a further complication, the power required to drive such pumps also varies in a ratio of the cube of the speed.
SUMMARY OF THE INVENTION
The present invention overcomes the above briefly described and other deficiencies and disadvantages of the prior art by providing a novel pressure booster system and a fluid flow distribution circuit incorporating such booster system. The present invention is based on the fact that it is possible to drive the rotor of any rotary pump in two directions. This inherent possibility has never been exploited because the potential usefulness thereof has not been appreciated and, perhaps more particularly, because the desire for maximum efficiency has led to a sacrifice of pump performance in one of the possible directions of rotation in favor of the other. Nevertheless, pumps are commercially available which will operate with a reasonable degree of efficiency in the "off-design" direction. Consequently, it is possible to employ pumps which may be selectively caused to rotate in either direction giving two different flow rates for each pump and, in a distribution system, giving 2n flows per n pumps.
Thus, in accordance with the present invention, one or more pump units, each comprising two pumps having the same characteristics, are employed to provide 2n flows by utilizing each pump in both rotational directions. This provides a plurality of pump combinations which, in turn, enables provision of a system having a highly desirable pressure-flow curve.
A particularly advantageous feature of the present invention is that it permits the use of a single reserve pump, if necessary or desired, because all pumps used in the system are identical.
BRIEF DESCRIPTION OF THE DRAWING
The present invention may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawing wherein like reference numerals refer to like elements in the several figures and in which:
FIG. 1 is a graphical presentation depicting operation of the present invention;
FIG. 2 is a schematic representation of an electrical control circuit for the present invention; and
FIG. 3 is a schematic isometric view of a preferred embodiment of the invention which may utilize the control circuitry of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 the abscissa of the graph represents increasing flow rates while the ordinate indicates increases in pressure. FIG. 1 relates to a group of two pumps, designated PA and PB, with the designations being followed by a (+) or (-) according to whether the pump in question is rotating in the "direct" or "opposite" direction. In the context of this disclosure the direct direction is the direction of highest performance efficiency and is indicated (+) and while the opposite direction is the direction of lowest performance and is indicated by (-). Although better results can be obtained, a typical ratio of the compression levels for a pump, depending whether it turns in the (+) or (-) direction, is about 0.66. It is to be noted that this ratio increases when the pumps have their intake ports connected to a pressurized distribution system. As noted above, bi-directional pumps suitable for use in the present invention are commercially available. Such pumps may, for example, comprise centrifugal pumps.
In FIG. 1 the point N represents the peak flow and pressure guaranteed by the system. It may thus be considered that the solid line parallel to the axis of the flows and passing through the point N represents the theoretical Piezo-metric level of the system although the true curve is shown as broken line N'. Thus, as will become obvious from the discussion below, the ratio of the compression levels for low flows is further improved, a fact which in practice is ignored, and the margin of uncertainty improved with the use of the present invention.
In the selected operating mode, explained below, the following curves are used:
Pa(-) -- represents operation of pump A only and in the (-) direction;
Pa(-) + pb(-) -- represents operation of pumps A and B in parallel and both in the (-) direction;
Pa(+) -- represents operation of pump A only and in the (+) direction;
Pa(+) + pb(+) -- represents operation of pumps A and B in parallel and in the (+) direction; and
T -- represents the increase in load losses in the circuit as the flow increases with ideal or theoretical operation.
The actual preferred operating mode is represented by the saw-toothed curve shown as an unbroken line based on the curve T. At the upper part of FIG. 1 portions of a typical cycle, represented in terms of percent of time in a typical 24 hour period, during which the flow probably will be within certain regions have been indicated.
In terms of FIG. 1, the operation of the invention is as follows:
Over the larger portion of the day, indicated as 90% on the diagram, pump PA(-) rotates and supplies the required flow while maintaining circuit pressure at levels up to that corresponding to point M on FIG. 1. As soon as pressure M is reached by the development of the required flow by pump PA the second pump PB(-) will be caused to support pump PA(-) by operating in parallel therewith. If, after a predetermined time, the pressure M is not detected by a pressure sensitive switch 26 (FIG. 2), pump PB(-) will be stopped and only pump PA(-) will continue to rotate. However, if the pressure remains above that of point M, pumps PA(-) + PB(-) will continue to operate in parallel. If, with the pumps operating in parallel in the (-) direction, the system pressure reaches a level corresponding to point P, both the pumps PA(-) and PB(-) will be stopped and pump PA will be restarted in the (+) direction. Pump PA(+) will remain in operation until the pressure reaches that corresponding to point R. Should pressure level R be reached pump PB is started in the (+) direction and thus pump PB(+) supports pump PA(+) by parallel operation. If, after a predetermined time, a pressure corresponding to that of point S is detected, the parallel operation continues until pressure level K is reached. When pressure level K is no longer detected, pump PB(+) will be stopped and the mode of operation with PA(+) alone operating is resumed.
In FIG. 1, the broken lines passing respectively through points M, P and R and parallel to the axis of flow respectively indicate the pressure levels at which pump PB(-) starts operating, pump PA(+) starts operating, and pump PB(+) starts operating. The relative position of these three parallel lines is a consequence of and therefore a characteristic of the operating mode selected as the preferred mode of operation of the invention.
The points Q and S on FIG. 1 correspond to a time delay, after a pump initiation, after which the flow may be considered as momentarily stabilized. The provision of such time delays is in the interest of preventing "pumping" of the device in the vicinity of the peaks of the curve; i.e., the time delays prevent too frequent changes in the system operational mode. The length of the time delays are determined experimentally and depend on the anticipated flow demand changes to be imposed on the delivery circuit.
Taking into account the practical distribution of the high and low flows of the operative period depicted in FIG. 1, which as noted is a 24 hour day, it may be seen that pumps PA and PB operating in the (-) direction will fulfill 70% of the requirements imposed on the system. During the remainder of the time excess pressure on the order of 1 to 3 bars will permit the supply of increasingly high flows. It is to be noted that this pressure range corresponds to a maximum pressure commensurate with that which would have been attained employing the conventional prior art hydro-pneumatic type boosters for which the regulation range would necessarily have to be entirely above the point K of FIG. 1.
It is also to be noted that, in the above discussed example which relates to an installation with two pumps, it will usually be considered necessary to have a third pump in reserve. The preferred operational mode is to keep the reserve pump continuously operating. With the reserve pump continuously operating the saw-toothed curve of FIG. 1 will have two additional "teeth" which result in the overall curve approaching the ideal response to a closer degree. Obviously, in the three pump system when one pump breaks down the two remaining pumps will continue to provide the peak flow.
FIG. 2 depicts an electric circuit for control of the distribution system described above in the discussion of FIG. 1. In FIG. 2 the relays of the control circuitry are represented schematically and the same reference characters have been applied to the relay solenoids and the switch contacts controlled thereby. Also, in the interest of facilitating understanding of the invention, several of the switches or terminals have been shown twice in FIG. 2.
The drive motors MA and MB respectively for pumps PA and PB may be presumed to be three phase electric motors supplied by three phase alternating current. The alternating current supply will be converted into a low voltage direct current for use in the control circuitry by means of a power supply including a transformer and rectifier. In the hydraulic circuit represented in FIG. 3, the pumps PA and PB are connected in shunt between the supply circuit 3 and the delivery circuit 4. The delivery pressure is sensed by means of pressure sensitive devices MO, PR1 and PR2. The pairs of ganged relay contacts, indicated at 50 and 51 (FIG. 2), are employed to supply lower to pump motors MA and MB. Relay contacts 50 and 51 are mechanically interconnected as indicated schematically at 52.
The control device includes a four position selector switch 53. Switch 53 has two stop positions and two positions which control respectively the excitation of the solenoids or relays of R1 and R2. Relays R1 and R2 supply power for initiating operation of the drive motor MA of priority pump PA and are typical of similar such relays conventionally employed in motor starting circuits. Conventional protective devices, indicated schematically as MET are incorporated in the system to prevent the operation of pump PA when there is no fluid at the pump inlet. As noted above, PR1 and PR2 denote pressure sensitive switches and whereas MO denotes a manometer type device which typically will have two contacts; all of devices PR1, PR2 and MO having a time delay.
Presuming that pump PA has been selected as the priority pump, the excitation of relay R1 by proper closing of switch 53 causes excitation of relay R3 insuring, by the closing of contacts 21-22, the excitation of relay PA(-). Excitation of relay PA(-) will cause the closing of contacts 51 and 52 and will result in the starting of pump PA in the (-) direction.
Referring jointly to FIGS. 1 and 2, pump PA(-) being supposed in service, when the pressure level corresponding to point M is detected by device MO, the contacts 7-10 and 7-27 of device MO will close causing the closing of relay R1 and the excitation of relay RT 1. Excitation of relay RT 1 will, by means of relay RP B(-) cause the closing of contacts 50-51; whereby power will be supplied to motor MB of pump PB causing PB to start in the (-) direction. After a predetermined time, if the pressure corresponding to point M is no longer detected by device MO, the contacts of the device will open and, via the action of relay R2, the pump PB will be stopped and the PA(-) mode of operation resumed.
However, if the pressure corresponding to point M is detected, the PA(-) + PB(-) operational mode continues until the pressure corresponding to point P is reached.
When the pressure corresponding to point P of FIG. 1 is detected by switch PR1, switch PR1 causes the excitation of relay RT 2. Excitation of RT 2 causes, via the excitation of relay RP A(+), the starting of pump PA in the (+) direction. Excitation of RT 2 also causes, by means of relay R2, contacts 21-22 and 24-25 to open thus shutting down pump PB(-). After a predetermined time, if the pressure corresponding to P is not detected, relay RT 2 is deenergized causing the PA(-) + PB(-) mode of operation to resume. If, on the other hand, pressure P is detected the PA(+) operational mode continues until the pressure corresponding to point R is reached.
When pressure R is detected by switch PR2, the contacts of this switch close causing the excitation of RT 3 whereby pump PB is started in the (+) direction.
If, after a further predetermined time delay, the pressure S is detected by PR2, the mode of operation PA(+) + PB(+) continues until a pressure level corresponding to point K of FIG. 1 is reached. If, however, the pressure falls below level R, the contacts of switch PR2 open causing relay RT 2 to be deenergized and, by means of relay R3, the motor MB of pump PB to be stopped.
It is to be noted that switches 54 and 55 are controlled by thermo-magnetic relays, not shown, which act as safety devices to guard against overloading or unbalance of the pump drive motors. Also, indicator lights 56 and 57 are provided. Control equipment for a stand-by pump may be connected in parallel with the indicator lights. A number of push button type switches MF, MF PR 1 , MF PR 2 have been shown. These push button type switches serve solely for control of the installation manually when the automatic control is out of service or for operation of the priority pump at a reduced level.
While a preferred embodiment has been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.
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Systems for delivering fluid at substantially constant pressure to consuming loads which exhibit widely varying demands. The systems employ parallel connected booster pumps which may be operated in either of two rotational directions to provide two output flow rates for each pump.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Utility Patent Application claims priority to German Patent Application No. DE 10 2004 003833.3, filed on Jan. 26, 2004, which is incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to a transmission and/or reception unit (“transceiver”) in particular for transmitting and/or receiving DSL (digital subscriber line) data.
[0003] So-called DSL linecards, that is, transmission/reception devices, of a central office (CO) for DSL communication have different so-called granularities, that is, numbers of supported channels. Granularities of 8, 24, 32, 48, 64, or 96 are customary. Individual DSL chip sets have either 12 channels or 16 channels; the usual granularity of 48 therefore has to be divided into 48 (4×12) and 48 (3×16) depending on the DSL chip set on which the linecard in question is based.
[0004] In particular, there are ASICs (application-specific integrated circuits) for the processing of data received by a DSL transceiver, or data to be transmitted, which support precisely 12 channels on an interface for this DSL transceiver. The interface used is then customarily a UTOPIA interface according to the ATM Forum standard (ATM=asynchronous transfer mode).
[0005] FIG. 3 schematically illustrates such a chip set or DSL transceiver 11 . A transceiver module 12 transmits or receives data signals over a transmission line 15 and delivers them at the back, that is, for processing, via an interface 13 , for example a UTOPIA interface. A data line 14 , which has 12 channels or 16 channels depending on the chip set being used, can be connected to this interface 13 .
[0006] Owing to the situation described above, each manufacturer with a corresponding DSL chip set can address only some of the aforementioned granularities without overhead, that is, without unused channels. With 12-channel chip sets, it is possible to produce granularities of 24, 48 (4×12), 72 and 96 without overhead, and granularities of 32, 48 (3×16), 64 and 96 with a 16-channel chip set.
[0007] Conventionally, non-matching granularities are produced by implementing the next-highest possible channel number on the linecard and simply not using the unneeded channels. In order to build a 64-channel linecard with a 12-channel chip set, for example, the linecard is configured for 72 channels which gives an overhead of eight unused channels.
[0008] Overall, there is a great need for the granularities which can be produced by means of a 16-channel chip set. When using the aforementioned 12-channel ASICs, however, the problem arises that a 48-channel linecard cannot be built simply from three 16-channel chip sets or transceivers, since only 12 channels of an interface of the DSL transceiver in question can be used by each ASIC. A manufacturer of a 16-channel chip set must therefore use four transceivers to build such a 48-channel linecard, but with only 48 out of the theoretically available 64 channels then being used, that is to say there is an overhead of 16 channels whose production entails costs but which are not needed.
[0009] A transmission and/or reception unit in which the available channels can be used more flexibly is needed.
SUMMARY
[0010] In accordance with one embodiment of the invention, a transmission and/or reception unit is provided. The unit has a module for transmitting and/or receiving data over a plurality of channels, in which the transmission and/or reception unit has at least two interfaces assigned to the module, for extracting received data and/or for delivering data to be transmitted, the plurality of channels being divided between the at least two interfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.
[0012] FIG. 1 illustrates a transmission and reception unit in accordance with one embodiment of the invention.
[0013] FIG. 2 illustrates a transmission and reception device with three transmission and reception units according to FIG. 1 .
[0014] FIG. 3 illustrates a transmission and reception unit in accordance with the prior art.
DETAILED DESCRIPTION
[0015] In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
[0016] In one embodiment, the module is a transceiver module, in particular a DSL transceiver module. Generally speaking, the term module refers to a chip or a chip set, in particular a circuit encapsulated in a single package. In the case of a chip set, there is at least one single chip which is interconnected with the at least two interfaces.
[0017] There may in particular be 16 channels, one of the at least two interfaces being assigned 12 channels and another of the at least two interfaces being assigned 4 channels. The interfaces may in this case be UTOPIA interfaces.
[0018] In one embodiment of the present invention, the transmission and/or reception unit can be operated in a first operating mode and in a second operating mode, the at least two interfaces working as separate interfaces in the first operating mode and the at least two interfaces working as a combined interface in the second operating mode. This means that the at least two interfaces, so to speak, are internally or externally combined together into a single interface.
[0019] Flexible allocation of channels is possible with such a transmission and/or reception unit, and in particular different granularities can be produced without overhead. To this end, at least two of these transmission and/or reception units are used in a transmission and/or reception device, one of the at least two interfaces of each of the at least two modules being respectively connected to a common processing unit, such as an ASIC, whereas others of the at least two interfaces are respectively connected to their own such processing units.
[0020] FIG. 1 illustrates a transmission and reception unit 1 (“transceiver”) according to one embodiment of the invention. Via a data line 7 , data are transmitted over 16 parallel channels from a transceiver module 2 , or received by it. The data of the individual channels may in principle be transmitted and received either over separate parallel lines or in any multiplex method over a single line. The transceiver module 2 delivers the received data to a first interface 3 and to a second interface 4 , or receives the data to be transmitted via this first interface 3 or this second interface 4 .
[0021] Twelve channels are in this case assigned to the first interface 3 and can be transmitted over first data lines 5 to further circuit units, or received from them. The second interface 4 is accordingly assigned 4 channels, the data of which can be delivered over second data lines 6 or received from other circuit parts.
[0022] If need be, such a transmission and reception unit may of course also be configured as a pure transmission unit or as a pure reception unit. A number of channels other than 16 and a different allocation of the channels to the interfaces is also conceivable, and there may likewise be more than two interfaces.
[0023] In one application of xDSL data communication, one embodiment of the transceiver module 2 is an xDSL transceiver module and the first interface 3 and the second interface 4 are so-called UTOPIA interfaces, an interface standard which is employed particularly in xDSL data transmission.
[0024] The first and second interfaces operate as separate interfaces in a first operating mode of the transmission and reception unit. There may also be a second operating mode, in which the first interface 3 and the second interface 4 are connected together, which leads to the case of a conventional 16-channel transmission and reception unit in the aforementioned embodiment.
[0025] FIG. 2 illustrates a transmission and reception device according to one embodiment of the invention, which shows how the problem described in the introduction of building a 48-channel linecard with 12-channel ASICs can be resolved by such a transmission and reception unit as represented in FIG. 1 .
[0026] The device illustrated in FIG. 2 comprises three transmission and reception units 1 , as were described with reference to FIG. 1 . Four processing units 8 , 9 are furthermore provided, for example the aforementioned ASICs which in this context are referred to as “backplane ASICs”. Each of these processing units 8 is designed to process 12 channels.
[0027] As illustrated in FIG. 2 , the first interface 3 of each transmission and reception unit 1 is respectively connected to one processing unit 8 . The second interfaces 4 of the three transmission and reception units 1 are coupled together and connected to another processing unit 9 , which in principle is configured exactly the same as the processing units 8 . Each of the processing units 8 , 9 is therefore responsible for 12 channels, and, with three transmission and reception units 1 each of which is configured for 16 channels, it is thereby possible to build a 48-channel linecard by using 12-channel ASICs.
[0028] In this case, the processing units 8 , 9 are respectively masters on the interfaces 3 and 4 , that is to say for example they set a rate at which data are transmitted over the interfaces 3 , 4 . The transceiver modules 2 are accordingly slaves in relation to these interfaces. With this configuration, a plurality of interfaces can then be assigned to a single processing unit (in the present example, the processing unit 9 ), but it is not possible to assign one interface to a plurality of processing units. In principle, a reverse configuration might also be conceivable.
[0029] Data lines 10 are then used for connecting the processing units 8 , 9 to other circuits.
[0030] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.
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A transmission and/or reception unit is provided. The transmission and/or reception unit includes a module for transmitting and/or receiving data over a multiplicity of channels and at least two interfaces, the multiplicity of channels being divided between the at least two interfaces. With such a transmission and/or reception unit, for example, flexible adaptation of DSL linecards with different granularities is possible.
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BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to web-indexing apparatus for use, for example, in label overprinting machines.
(2) Summary of the Prior Art
The requirement to index a web intermittently is encountered in many machines one example being self-adhesive label overprinting machines in which it is necessary to advance the web through the machine at the instant of printing by a rotary type drum. In previous proposals, in such machines the indexing of the web has been effected by purely mechanical means but such previous machines have the disadvantage that it is necessary to set-up mechanically a machine for any given run of labels on a web and this can be time-consuming and, moreover, the accuracy is not always as high as is desirable, with the result that registration is lost over a long run of labels.
As printing speeds increase and hence the velocity of the web of labels through the machine, it becomes even more essential accurately to synchronise the arrival of a given label at the printing station than in relatively low speed machines hitherto used.
SUMMARY OF THE INVENTION
According to the present invention there is provided web-indexing apparatus comprising first and second rotary members arranged to define a nip through which the web can pass, one of said rotary members having an interrupted periphery defining a step, means mounting said one rotary member for movement towards and away from the other rotary member such that when the members are brought into proximity with the interrupted periphery opposite the periphery of the other member, the step of the one rotary member will subsequently engage the web and the periphery of the other rotary member at an exact instant to thereby advance the web, solenoid means operative to bring the rotary members into and remove them from their co-operating, nip-forming, position, switch means operable in dependence upon the operational cycle of the apparatus to change the condition of the solenoid, and photo-electric cell means effective to change the condition of the solenoid in dependence upon a predetermined location on the web.
Further according to the present invention there is provided web-indexing apparatus comprising a first roller and a second roller capable of defining a nip to receive and index the web, the first said roller having an interrupted periphery defining a step, means mounting the second roller for movement towards and away from the first roller whereby the rollers can be made selectively to engage and to disengage from the web, the step of the first roller serving to initiate indexing of the web, a solenoid for controlling movement of the second roller towards and away from the first roller, switch means controllable by a continuously rotating member of the apparatus and connected in the solenoid circuit whereby to effect energization of the solenoid when the recessed part of the first roller is facing the second roller and photocell means for detecting a predetermined location of the web and connected in the solenoid circuit whereby to de-energize the solenoid when that location has been detected.
Still further according to the present invention there is provided an over-printing machine comprising reel support means for carrying a web of material to be over-printed, means for receiving the over-printed material, rotary members for advancing the web through the machine, one said rotary member having a recessed peripheral portion defining a step and the other said rotary member being arranged to co-operate with the first rotary member to advance the web through the machine, solenoid means for bringing the rotary members together, switch means connected in the solenoid circuit and arranged to energize the solenoid and photo-electric cell means operative in the solenoid circuit to deenergize the solenoid when a predetermined location on the web is reached.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a purely diagrammatic perspective view illustrating essential components of web-indexing apparatus in accordance with the invention;
FIG. 2 is a side elevation illustrating the basic features of a label-overprinting machine incorporating web-indexing apparatus which is a modification of that illustrated in FIG. 1;
FIG. 3 is a plan view of the machine illustrated in FIG. 2;
FIG. 4 is a section on the line 4--4 of FIG. 2;
FIG. 5 is a section on the line 5--5 of FIG. 2; and
FIG. 6 is a circuit diagram illustrating the control system of the machine of FIGS. 2 to 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A description of one embodiment of web-indexing apparatus will now be given with reference to FIG. 1.
Referring now to FIG. 1, a self-adhesive label web 10 is fed to the apparatus by feed means, not shown, which may be upstream or downstream through a bracket 12 carrying a photoelectric sensing device and a corresponding light source.
The web next passes through, at a predetermined spacing downstream of the photoelectric sensing device 12, two opposed rollers 14,15 each of which is mounted on a respective transverse shaft 16,18 which carries, at an end remote from the rollers, a respective gear wheel 20,22 the two gear wheels meshing so that the rollers are driven synchronously in opposite rotational senses.
The upper roller 14 does not have a periphery of constant radius but includes a recessed portion 24 defining a step 25, while in contrast the lower roller 15 has a continuous, smooth, periphery.
The shaft 18 carrying the lower roller 15 with the continuous periphery also has keyed thereto a cam 26 which cooperates with a micro-switch 28 incorporated in the circuit of a direct-acting solenoid 30. The shaft 18 is journalled at each end in bearings 32,34, the bearing 34 being mounted in a slide member 36 capable of very limited vertical movement along vertical guides 37 rigid with a bracket 38 carrying the solenoid winding 40. The slide member 36 is biased downwardly by a spring 42 and the armature of the solenoid, when energized, exerts a force upwardly on the slide member. The winding of the solenoid is supported in the bracket 38 through a cup 44 and an adjustable stop 46.
To the right (as shown) of the bearing block 32, an eccentric bush 48 receives and supports an end portion of the shaft 18. In the assembled condition the bush is mounted in the bearing block 32 and angular adjustment of the bush enables fine adjustment of the relative positions of the shafts 16,18 when the rollers 14,15 are in the operative, engaged, condition.
In practice the adjustment will be made on assembly and the bush 48 will be locked by a grub screw (not shown).
In operation, the bottom roller 15 is moved a small distance, say a few thousandths of an inch by the solenoid 30 up into the position ready for advancing the web, during the time that the recess 24 faces the roller 15. The solenoid is in the circuit of the micro-switch 28, and the latter may be replaced by a Hall Effect switch thereby avoiding the long term unreliability of micro switches.
The web is transported forwardly instantaneously and precisely when the leading edge or step 25 of the increased diameter portion of the upper feed roller 14 acts on the lower feed roller 15 through the web.
When the photo-electric device 12 senses a gap in the labels, or a perforation in the web, or other indicia, the solenoid 30 is de-activated so that the lower feed roller 15 no longer drives the upper feed roller and hence the web through the apparatus.
When the web transporting or feed apparatus is incorporated in an overprinting machine, apparatus in accordance with the invention can be included either upstream or downstream of the printing station.
It will be appreciated that the combination of photoelectric sensing plus a mechanical system for actual transportation of the web ensures the greatest possible accuracy and also makes possible higher speeds of operation than are possible purely with mechanical systems. This higher speed may well prove to be particularly necessary whenever higher speed printing techniques, such as dot printing or spray printing, are employed in print-out arrangements of computers.
Turning now to the machine illustrated in FIGS. 2 to 5, the machine includes a base casing 100 containing part of the drive system and a superstructure 102 carrying further parts of the drive system and operational members which serve to index a web of labels through the machine and to effect printing of labels on a web.
The web progresses from right to left and a reel is carried by a reel support 104 from which the web is dispensed to two dancer rolls 106, 108 mounted for oscillatory movement on an arm 109 carried by a boom 110 extending from the base casing 100. The path of the web is indicated in chain lines and is denoted 112. The arm 109 is biased by a spring, not shown, attached to an anchorage 111 which includes provision for adjusting spring tension. After passage through the dancer rolls 106, 108, the web passes beneath a pivotal arm 114 which under its self-weight holds the label web firmly on the upper plate 116 of the casing 100.
The web then passes beneath a photo-electric cell 117 (already referred to with reference to FIG. 1) and thereafter passes between the lower roller 15 and the upper interrupted roller or cam 14 which together serve intermittently to advance the web through the machine. The web and the labels thereon next encounter a type drum 120 which cooperates with a platen roller 121 (FIG. 5) to effect printing on the successive labels at precisely the right position controlled by a Hall Effect switch cooperating with a continuously rotating shaft of the machine and with the photo-cell and associated circuitry shown in FIG. 6. Thereafter the web passes over further rollers (not shown) and is either rewound after a suitable time interval from the instant of printing or alternatively a cutting mechanism not forming part of the present invention is disposed downstream of the type drum and, in operation, the individual labels and their backing are cut and formed into a stack. The take-up reel (not shown) on the cutter mechanism (likewise not shown) is driven by a gear wheel 180 meshing with a gear wheel 181 (FIG. 5) fast for rotation with the platen roller.
Power for the machine is provided by a drive motor 130 which drives a gear train 132 through belts 134 and the gear train serves both to drive the lower roller 15 and the upper cam 14 and also through a pinion 136 drives a gear wheel 138 fast for rotation with the type drum. The cliches of the type drum 120 are inked by a transfer roller 140, the position of the spindle of which is adjustable by a screw 141 and this roller receives ink from a larger diameter roller 142 in contact with the internal roller of an ink fountain 144. The ink fountain has a single screw member 145 for adjusting the amount of ink delivered as a film of constant thickness to the rollers 142 and 140. Full details of this inking fountain are given in Ser. No. 969,966 filed Dec. 15, 1978 and now abandoned.
Means are provided to adjust the relative position of the printing platen 121 in relation to the type drum 120 and an adjustment is provided for adjustment of the take-up speed at the take-up reel (not shown).
The printing platen roller adjusting means includes a solenoid 170, the plunger 172 of which is connected a clevis 174 to a rod 176, partly screw-threaded, which in turn carries a knob 178 by which fine adjustment can be effected of the distance between the cliches and the platen 121. The solenoid 170 can also be actuated to bring the platen to the printing position and to space it away from the type drum. The shaft of the platen 121 is mounted in an eccentric bush 182 to enable fine adjustment as well as "on/off" operation to be effected. By provision of an appropriate push-button, the machine can be brought to a ready-to-print condition independently of the label web feed.
Turning now to the details of the photo-electric cell sensor 12, the photo transistor 160 which is the critical operative portion of the sensor is mounted on an arm 162 and the position of the photo transistor can be adjusted laterally of the label web while the arm itself is mounted on a screw-threaded member 164 enabling adjustment of the arm by means of a knob 166 in the length direction of the machine and of the label web.
The operating lamp for the photo transistor 160 is in the form of an infra-red wafer source and is not illustrated. It is mounted on a transverse arm (not shown) mounted for movement with the arm 162.
As described in outline with reference to FIG. 1, immediately the micro-switch 28 or the Hall Effect switch has been energized by the motion of the corresponding shaft of the machine, the solenoid 30 is energized thereby moving the axis of the roller 15 upwardly by a short distance (of the order of a few thousandths of an inch) so that on rotation to the step 25 of the cam 14, and thereafter on the higher portion of its periphery, the web is driven through a predetermined distance and after printing effected by the type drum motion of the web ceases. As illustrated in FIGS. 2 and 4 the solenoid 30 has an armature which extends upwardly through the casing and the upper end of the armature engages one of the bearing assemblies 34 (FIGS. 1 and 4) of the roller support shaft 18 so that when energized the roller is raised through a small distance for the required period of time just before the roller engages the step and subsequently the higher periphery of the cam 14. Once a given label has passed the roller 15 or a given indicia on the label has passed, the photo transistor senses this and deenergizes the solenoid 30 allowing its armature to drop down, thereby halting transportation of the web. The cycle of operation is then resumed when the micro-switch 28 on the Hall Effect switch re-energizes the solenoid 30.
Details of the circuit providing for cooperative operation of the roller and cam arrangement 14,15 will be apparent from FIG. 6.
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A label web overprinting machine in which the label web is indexed through the apparatus by two opposed rollers, one of which has a recess in its periphery defining a step and the other of which is movable through a small distance to form a nip for drawing the web forwardly through a printing station of the machine.
A solenoid controls the movement of the movable roller and by a machine cycle operated switch the solenoid is energized to bring the one roller into substantial contact with the other at an instant when the recess of the one roller is directed towards the other roller. Immediately the step of the roller contacts the other roller, the web is indexed forward and the solenoid is subsequently deenergized by a photo-electric cell arrangement arranged to detect a particular indicia on a label or the downstream edge of a given label.
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[0001] The present invention claims priority from EP Application No. 03076400.5 filed May 9, 2003, the contents of which are incorporated herein by reference in its entirety.
FIELD
[0002] The present invention relates to a lithographic apparatus. The present invention also relates to a method of manufacturing a device.
[0003] The present invention also relates to a lithographic projection apparatus comprising a radiation system for providing a projection beam of radiation; a support structure for supporting a patterning device, the patterning device serving to pattern the projection beam according to a desired pattern; a substrate holder for holding a substrate said substrate holder provided with a clamp to provide a holding force for pressing the substrate against said substrate holder; releasing device constructed and arranged to apply a release force to release said substrate from said substrate holder against said holding force; and a projection system for projecting the patterned beam onto a target portion of the substrate.
RELATED ART
[0004] The term “patterning device” as here employed should be broadly interpreted as referring to devices that can be used to endow an incoming radiation beam with a patterned cross-section, corresponding to a pattern that is to be created in a target portion of the substrate; the term “light valve” can also be used in this context. Generally, the said pattern will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit or other device (see below). Examples of such patterning devices include:
[0005] A mask. The concept of a mask is well known in lithography, and it includes mask types such as binary, alternating phase-shift, and attenuated phase-shift, as well as various hybrid mask types. Placement of such a mask in the radiation beam causes selective transmission (in the case of a transmissive mask) or reflection (in the case of a reflective mask) of the radiation impinging on the mask, according to the pattern on the mask. In the case of a mask, the support structure will generally be a mask table, which ensures that the mask can be held at a desired position in the incoming radiation beam, and that it can be moved relative to the beam if so desired;
A programmable mirror array. One example of such a device is a matrix-addressable surface having a viscoelastic control layer and a reflective surface. The basic principle behind such an apparatus is that (for example) addressed areas of the reflective surface reflect incident light as diffracted light, whereas unaddressed areas reflect incident light as undiffracted light. Using an appropriate filter, the said undiffracted light can be filtered out of the reflected beam, leaving only the diffracted light behind; in this manner, the beam becomes patterned according to the addressing pattern of the matrix-addressable surface. An alternative embodiment of a programmable mirror array employs a matrix arrangement of tiny mirrors, each of which can be individually tilted about an axis by applying a suitable localized electric field, or by employing a piezoelectric actuation device. Once again, the mirrors are matrix-addressable, such that addressed mirrors will reflect an incoming radiation beam in a different direction to unaddressed mirrors; in this manner, the reflected beam is patterned according to the addressing pattern of the matrix-addressable mirrors. The matrix addressing can be performed using a suitable electronic device. In both of the situations described hereinabove, the patterning device can comprise one or more programmable mirror arrays. More information on mirror arrays as here referred to can be gleaned, for example, from U.S. Pat. No. 5,296,891 and U.S. Pat. No. 5,523,193, and PCT patent applications WO 98/38597 and WO 98/33096, which are incorporated herein by reference. In the case of a programmable mirror array, the said support structure may be embodied as a frame or table, for example, which may be fixed or movable as needed; and
[0007] A programmable LCD array. An example of such a construction is given in U.S. Pat. No. 5,229,872, which is incorporated herein by reference. As above, the support structure in this case may be embodied as a frame or table, for example, which may be fixed or movable as needed.
[0008] For purposes of simplicity, the rest of this text may, at certain locations, specifically direct itself to examples involving a mask and mask table; however, the general principles discussed in such instances should be seen in the broader context of the patterning device as hereinabove set forth.
SUMMARY
[0009] Lithographic projection apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, the patterning device or patterning structures may generate a circuit pattern corresponding to an individual layer of the IC, and this pattern can be imaged onto a target portion (e.g. comprising one or more dies) on a substrate (silicon wafer) that has been coated with a layer of radiation-sensitive material (resist). In general, a single wafer will contain a whole network of adjacent target portions that are successively irradiated via the projection system, one at a time. In current apparatus, employing patterning by a mask on a mask table, a distinction can be made between two different types of machine. In one type of lithographic projection apparatus, each target portion is irradiated by exposing the entire mask pattern onto the target portion in one go; such an apparatus is commonly referred to as a wafer stepper or step-and-repeat apparatus. In an alternative apparatus—commonly referred to as a step-and-scan apparatus—each target portion is irradiated by progressively scanning the mask pattern under the projection beam in a given reference direction (the “scanning” direction) while synchronously scanning the substrate table parallel or anti-parallel to this direction; since, in general, the projection system will have a magnification factor M (generally <1), the speed V at which the substrate table is scanned will be a factor M times that at which the mask table is scanned. More information with regard to lithographic devices as here described can be gleaned, for example, from U.S. Pat. No. 6,046,792, which is incorporated herein by reference.
[0010] In a manufacturing process using a lithographic projection apparatus, a pattern (e.g. in a mask) is imaged onto a substrate that is at least partially covered by a layer of radiation-sensitive material (resist). Prior to this imaging step, the substrate may undergo various procedures, such as priming, resist coating and a soft bake. After exposure, the substrate may be subjected to other procedures, such as a post-exposure bake (PEB), development, a hard bake and measurement/inspection of the imaged features. This array of procedures is used as a basis to pattern an individual layer of a device, e.g. an IC. Such a patterned layer may then undergo various processes such as etching, ion-implantation (doping), metallization, oxidation, chemo-mechanical polishing, etc., all intended to finish off an individual layer. If several layers are needed, then the whole procedure, or a variant thereof, will have to be repeated for each new layer. Eventually, an array of devices will be present on the substrate (wafer). These devices are then separated from one another by a technique such as dicing or sawing, whence the individual devices can be mounted on a carrier, connected to pins, etc. Further information regarding such processes can be obtained, for example, from the book “Microchip Fabrication: A Practical Guide to Semiconductor Processing”, Third Edition, by Peter van Zant, McGraw Hill Publishing Co., 1997 , ISBN 0-07-067250-4, which is incorporated herein by reference.
[0011] For the sake of simplicity, the projection system may hereinafter be referred to as the “lens”; however, this term should be broadly interpreted as encompassing various types of projection system, including refractive optics, reflective optics, and catadioptric systems, for example. The radiation system may also include components operating according to any of these design types for directing, shaping or controlling the projection beam, and such components may also be referred to below, collectively or singularly, as a “lens”. Further, the lithographic apparatus may be of a type having two or more substrate tables (and/or two or more mask tables). In such “multiple stage” devices the additional tables may be used in parallel, or preparatory steps may be carried out on one or more tables while one or more other tables are being used for exposures. Dual stage lithographic apparatus are described, for example, in U.S. Pat. No. 5,969,441 and the PCT application WO 98/40791, both of which are incorporated herein by reference.
[0012] Although specific reference may be made in this text to the use of the apparatus according to the invention in the manufacture of ICs, it should be explicitly understood that such an apparatus has many other possible applications. For example, it may be employed in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, liquid crystal display panels, thin film magnetic heads, etc. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms “reticle”, “wafer” or “die” in this text should be considered as being replaced by the more general terms “mask”, “substrate” and “target portion”, respectively.
[0013] In the present document, the terms “radiation” and “beam” are used to encompass all types of electromagnetic radiation, including ultraviolet (UV) radiation (e.g. with a wavelength of 365, 248, 193, 157 or 126 nm) and extreme ultra-violet (EUV) radiation (e.g. having a wavelength in the range 5-20 nm), as well as particle beams, such as ion beams or electron beams.
[0014] In the conventional lithographic projection apparatus, during photolithographic processes, the wafer is firmly clamped on the wafer holder by a holding force, that may range from vacuum pressure forces, electrostatic forces, intermolecular binding forces or just gravity force. The wafer holder defines a substantially flat plane, usually in the form of a plurality of protrusions defining an even flat surface on which the wafer is clamped. Tiny variations in the height of these protrusions are detrimental to image resolution, since a small deflection of the wafer from an ideal flat plane orientation may result in rotation of the wafer and a resulting overlay error due to this rotation. In addition, such height variations of the wafer holder may result in height variation of the wafer that is supported thereby. During the photolithographic process, such height variations may affect image resolution due to a limited focal distance of the projection system. Therefore it is desirable to have an ideal flat wafer holder.
[0015] It has come to the attention of the inventors that this clamping force may cause problems when the wafer is released from the wafer holder.
[0016] A conventional ejection mechanism is arranged in a way to step up an release force to a substantially high level, thereby biasing the wafer in an initial biased configuration and then wait until the wafer is released from the wafer holder through conversion of this bias energy into a releasing action. For example, when a vacuum pressure is used as clamping force, the wafer is initially bent substantially away from the wafer holder at a central position of the wafer. Then, the wafer releases from the wafer holder through conversion of this bending energy to release action, while reducing the vacuum pressure to a substantial ambient pressure when the wafer is released from the wafer holder.
[0017] Usually, to provide such release force, a tripod of three ejection pins (e-pins) is used, which engage at three spaced apart locations of the wafer and provide a releasing force to disengage the wafer from the wafer holder. The energy that is built up in the wafer during this stepping up of the release force is converted into displacement by subsequent release of the wafer surface from the wafer holder surface. However, this built up energy may also cause damage to the wafer and or wafer holder.
[0018] The invention aims to overcome this problem by providing a photolithographic machine, wherein this problem is addressed and wherein the amount of energy left, when the wafer is finally released from the wafer holder, is not detrimental for the wafer and/or wafer holder.
[0019] This aspect is achieved by a lithographic projection apparatus according to the preamble, wherein the lithographic projection apparatus comprises a controller for applying a release force that is reduced preceding to final release.
[0020] In this way, since the release force, preceding to final release, is lowered by the controller, the amount of energy that may be damaging to the wafer and/or wafer holder, in particular the amount of energy acting on the holding region for holding the wafer in a flat position, is reduced in comparison with a constant release force, wherein the wafer releases from the wafer holder with a sudden movement and wherein, after release the release force is lowered drastically instead of a lowering thereof in advance of the final release moment.
[0021] By reduction of the release force during release, the amount of energy absorbed by the wafer is lowered, so that during the release thereof, this energy is not damaging to the wafer and/or wafer holder.
[0022] Preferably the release force is controlled such that the release force at final release is less then 70% of the maximum release force. Still more preferably, the release force is controlled relative to a preset release height of the releasing device. In particular, the difference between an actual wafer height near the e-pins and a preset release height is measured. This actual height of the wafer during release determines the maximum angle of rotation of the wafer, especially in the vicinity of the final release area where the substrate finally releases from the wafer holder and is dependent on the release force applied to the wafer during final release. By keeping the angle of rotation low, the maximum amount of energy to be transferred to the wafer holder is low, thereby keeping the wafer and/or wafer holder intact since the amount of energy is kept below a threshold value that is maximally absorbable.
[0023] In a preferred embodiment the preset height is chosen so as to generate a maximum angle of deflection of 2 mrad. Here, the preset height for a 200 mm wafer is smaller than 1.0 mm, preferably smaller than 0.5 mm. To absorb excess energy still left during the final release of the wafer from the wafer holder, preferably, the wafer holder comprises a protective rim for absorption of wear energy. In this way, the energy is absorbed by a zone of the wafer holder where the flatness is not crucial. Hence, in the photolithographic process, flatness can be maintained.
[0024] The invention further relates to a device manufacturing method comprising the steps of: providing a substrate that is at least partially covered by a layer of radiation-sensitive material; providing a holding force for pressing the substrate against a substrate holder; providing a projection beam of radiation using a radiation system; using a patterning device or a patterning structure to endow the projection beam with a pattern in its cross-section; projecting the patterned beam of radiation onto a target portion of the layer of radiation-sensitive material; and applying a release force so as to release the substrate from the substrate holder against the holding force. According to the invention, the method comprises the step of controlling the releasing device so as to apply a release force that is reduced preceding to final release.
[0025] Preferably, the release force and/or the release height are determined in-process in an iterative way. In this way, in a high-throughput photolithographic process, the amount of releasing force to be applied to the wafer can be easily and quickly found without causing unnecessary damage to the wafer holder.
[0026] Still more preferably, the release force and/or the release height are determined based on recently in-process applied release forces and/or release heights. Such recent results, for example, a statistical averaging of the last ten results, will offer the best heuristic values, while keeping the damage to the wafer to a minimum.
[0027] In a further aspect, the invention relates to a lithographic apparatus according to the preamble, wherein the substrate holder comprises a protective rim for absorption of wear energy. Such a protective rim absorbs any excess release energy left after release of the substrate from the substrate holder, while keeping the substrate holder itself intact.
[0028] In a still further aspect, the invention relates to a device manufacturing method comprising the steps of: providing a substrate that is at least partially covered by a layer of radiation-sensitive material; providing a holding force for pressing the substrate against a substrate holder; providing a projection beam of radiation using a radiation system; using a patterning device or patterning structure to endow the projection beam with a pattern in its cross-section; projecting the patterned beam of radiation onto a target portion of the layer of radiation-sensitive material; applying a release force so as to release the substrate from the substrate holder against the holding force; and determining the release force and/or an release height in-process in an iterative way.
BRIEF DESCRIPTION OF DRAWINGS
[0029] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:
[0030] FIG. 1 depicts a lithographic projection apparatus according to an embodiment of the invention;
[0031] FIG. 2 depicts the initial stage of release of a wafer from a wafer holder in accordance with an embodiment of the invention;
[0032] FIG. 3 depicts the final stage of release of a wafer from a wafer holder in accordance with an embodiment of the invention;
[0033] FIG. 4 depicts a detailed illustration of the wafer and the wafer holder in the final stage of release in accordance with an embodiment of the invention;
[0034] FIG. 5 depicts a conventional force-diagram of an ejection of a wafer from a wafer holder;
[0035] FIG. 6 depicts a modified force-diagram showing ejection control of the wafer according to embodiments of the invention;
[0036] FIG. 7 depicts an illustration of the energy absorbed by the wafer holder during the final stage of release in accordance with an embodiment of the invention.
DETAILED DESCRIPTION
[0037] FIG. 1 schematically depicts a lithographic projection apparatus according to a particular embodiment of the invention. The apparatus comprises:
a radiation system Ex, IL, for supplying a projection beam PB of radiation (e.g. light in the deep ultraviolet region). In this particular case, the radiation system also comprises a radiation source LA; a first object table (mask table) MT provided with a mask holder for holding a patterning device, illustrated in the form of the mask MA (e.g. a reticle), and connected to first positioning device PM for accurately positioning the mask with respect to item PL; a second object table (substrate table) WT provided with a substrate holder for holding a substrate W (e.g. a resist coated silicon wafer), and connected to second positioning device PW for accurately positioning the substrate with respect to item PL; and a projection system (“lens”) PL for imaging an irradiated portion of the mask MA onto a target portion C (e.g. comprising one or more dies) of the substrate W.
[0042] As here depicted, the apparatus is of a transmissive type (i.e. has a transmissive mask). However, in general, it may also be of a transmissive type, for example (with a transmissive mask). Alternatively, the apparatus may employ another kind of a patterning device or patterning structure, such as a programmable mirror array of a type as referred to above.
[0043] The source LA (e.g. an excimer laser source) produces a beam of radiation. This beam is fed into an illumination system (illuminator) IL, either directly or after having traversed a conditioning device, such as a beam expander Ex, for example. The illuminator IL may comprise an adjusting device AM for setting the outer and/or inner radial extent (commonly referred to as s-outer and s-inner, respectively) of the intensity distribution in the beam. In addition, it will generally comprise various other components, such as an integrator IN and a condenser CO. In this way, the beam PB impinging on the mask MA has a desired uniformity and intensity distribution in its cross-section.
[0044] It should be noted with regard to FIG. 1 that the source LA may be within the housing of the lithographic projection apparatus (as is often the case when the source LA is a mercury lamp, for example), but that it may also be remote from the lithographic projection apparatus, the radiation beam which it produces being led into the apparatus (e.g. with the aid of suitable directing mirrors); this latter scenario is often the case when the source LA is an excimer laser. The current invention and claims encompass both of these scenarios
[0045] The beam PB subsequently intercepts the mask MA, which is held on a mask table MT. Having traversed the mask MA, the beam PB passes through the lens PL, which focuses the beam PB onto a target portion C of the substrate W. With the aid of the second positioning device PW (and interferometric measuring device IF), the substrate table WT can be moved accurately, e.g. so as to position different target portions C in the path of the beam PB. Similarly, the first positioning device PM can be used to accurately position the mask MA with respect to the path of the beam PB, e.g. after mechanical retrieval of the mask MA from a mask library, or during a scan. In general, movement of the object tables MT, WT will be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which are not explicitly depicted in FIG. 1 . However, in the case of a wafer stepper (as opposed to a step-and-scan apparatus) the mask table MT may just be connected to a short stroke actuator, or may be fixed. Mask MA and substrate W may be aligned using mask alignment marks M 1 , M 2 and substrate alignment marks P 1 , P 2 .
[0046] The depicted apparatus can be used in two different modes:
[0047] 1. In step mode, the mask table MT is kept essentially stationary, and an entire mask image is projected in one go (i.e. a single “flash”) onto a target portion C. The substrate table WT is then shifted in the x and/or y directions so that a different target portion C can be irradiated by the beam PB; and
[0048] 2. In scan mode, essentially the same scenario applies, except that a given target portion C is not exposed in a single “flash”. Instead, the mask table MT is movable in a given direction (the so-called “scan direction”, e.g. the y direction) with a speed v, so that the projection beam PB is caused to scan over a mask image; concurrently, the substrate table WT is simultaneously moved in the same or opposite direction at a speed V=Mv, in which M is the magnification of the lens PL (typically, M=¼ or ⅕). In this manner, a relatively large target portion C can be exposed, without having to compromise on resolution.
[0049] During the photolithographic processes, the wafer 1 is firmly clamped on the wafer holder 2 by a holding force, that may range from vacuum pressure forces, electrostatic forces, intermolecular binding forces or just gravity force. The wafer holder 2 defines a substantially flat plane, in the form of a plurality of protrusions defining an even flat surface on which the wafer 1 is clamped.
[0050] In FIG. 2 , an initial stage is shown, wherein a wafer 1 releases from a wafer holder 2 . The wafer holder 2 comprises support pins (e.g. cylindrical burls, not shown) having a height of approximately 100 μm. The burls are spaced apart from each other at a distance of approximately 3 mm. The burls have a diameter of approximately 0.5 mm. Each protrusion has an extremity remote from the face of the substrate holder and is thus embodied (dimensioned) that the said extremities all lie within a single substantially flat plane. The wafer holder 2 may be supported on a flat support 3 .
[0051] The wafer 1 is released from the holder 2 by ejection pins 4 , usually three in number (of which only two are shown), which are controlled by a controller 5 that-controls the displacement of the ejection pins 4 . Such a controller 5 may be a software routine, that controls the functioning of for example an electrical motor 6 that drives the ejection pins 4 . In addition, the controller 5 may be implemented in hardware elements, for instance in a design that uses preconfigured digital and/or analog hardware elements that are responsive to certain detection inputs 7 of the ejection system 8 . The shape of wafer 1 in FIG. 2 can be characterized as a bell shape, that is, in this stage, the wafer is only in the center region near the ejection pins released. The ejection pins provide an release force on the wafer, resulting in a biasing of the wafer 1 so that energy is stored in bending the wafer. The wafer 1 releases from the substrate holder in the central region, while the outer regions of the wafer 1 are still clamped to the substrate, due to a vacuum suction force.
[0052] FIG. 3 shows a schematic view of the substrate 1 in the final stage of release. In this stage, the wafer has a “bowl” shape, that is, nearly all parts of the wafer 1 are released and there is only contact between the outer region of the wafer and the wafer holder. In this stage, the shape of the wafer is substantially convex, so that, as will be explained further with reference to FIG. 4 , the wafer surface is slightly rotated with respect to the wafer holder. Such a rotation may introduce mechanical friction that potentially causes damage. The outer region in the example of FIG. 3 consists of only a few rings of concentric protrusions, or a sealing rim for creating a vacuum. The final release occurs when the wafer is rotated away from this outmost perimeter region of the wafer holder.
[0053] FIG. 4 shows a detailed view on the wafer 1 near the outmost perimeter region of the wafer holder 2 during release. In this example, the wafer holder 2 comprises a series of concentric burl rings, of which the second last burl ring 9 and last burl ring 10 are shown. Furthermore, the wafer holder 2 comprises a sealing rim 11 . The rim 11 is dimensioned to provide a “leaking” seal, that is, due to the small difference in height of the rim 11 and the burls 9 and 10 , air is able to enter the room formed between the burls. In this way, a clamp or holding force is generated that extends away from the center of the wafer up to the sealing rim, so that the substrate 1 is pressed substantially flat against the substrate holder 2 . When the wafer 1 rotates when the second last burl ring 9 no longer has contact with the wafer 1 , the wafer 1 will scrape across the point of contact 12 . This scraping is caused by the fact that the central line on the wafer rotates, which forces the bottom surface to move into the direction of the centre of the wafer holder 2 , illustrated by arrow P. The scraping distance is the rotation of the wafer multiplied by half the wafer thickness. The energy associated with the scraping effect can calculated as the product of force and displacement. The force is a friction force proportional to the vertical force generated between the wafer 1 and wafer holder 2 and will be maximal where the rotation of the wafer is maximal, hence near the boundaries of the wafer holder. Depending on the design of the wafer holder 2 , the last point of contact may be the last burl ring 10 , the outer rim 11 or even a further rim element 13 that may be used to absorb the scraping energy associated with the release action.
[0054] FIG. 5 depicts a conventional force-diagram of an ejection of a wafer from a wafer holder. In the diagram, three simultaneously occurring events are depicted: the upper line 14 illustrates a force applied on the substrate by the ejection pins; the medium line 15 illustrates a preset control curve of the wafer height in response to the application of said release force; the intermittent line just below medium line 15 illustrates the actual height of the wafer 1 in response to the application of said release force. The lower line 16 depicts the drop of the vacuum pressure (that is, the pressure difference to ambient pressure), which just after full release of the wafer drops to zero. In the diagram of FIG. 5 , it becomes apparent, that the release force drops after the wafer has been fully release, to a level that is sufficient for supporting the wafer 1 . In view of the discussion of the energy converted to scraping energy with reference to FIG. 4 , in FIG. 5 , it is apparent that the area below the force line 14 until the release moment 17 is equivalent to energy converted into release action; where the area below the force line 14 after release moment 17 is proportionate to scraping action and energy absorption near the boundary of the wafer holder 2 ; which may be damaging to the wafer 1 and/or wafer holder 2 . Here, the release moment 17 may be characterized as the moments the outer region of the wafer starts to release, in particular, the second last burl ring 9 , from the wafer holder 2 . From this release moment 17 the wafer edge rotates around the perimeter of the wafer holder 2 , in particular rim 11 . It is an insight of the invention that the area of the force line after this release moment 17 should be minimized as much as possible, hence to release the substrate 1 from holder 2 with a release force that is reduced prior to final release.
[0055] FIG. 6 shows an illustrative diagram showing a force line 14 ′ according to the invention. The force line is lowered prior to release, hence keeping the generated destructive energy to a minimum after release. Preferably, the lowering is controlled in a maximal steep descent 18 , thus applying maximum power while releasing the wafer, thus shortening the release time of the wafer. This results ideally in a force-characteristic substantially according to a block shape: Initially, the force is stepped up high to a clipping edge 19 to provide a maximum thrust, thereby releasing the wafer as soon as possible. The wafer height is preset to a predetermined set-point 15 , which is determined so that the wafer is released when set-point height is reached. The actual wafer height near the ejection pins is entered into a controller 5 , which determines, based upon a difference analysis between set-point height and actual height the release force to be applied relative to said preset release height of the ejection pins. This difference analysis may include a term proportional to the difference between set-point and actual height, plus time-integrated and time-differentiated terms of this actual difference.
[0056] FIG. 7 depicts a schematic estimate of the energy that is generated in the final stages of the release action of the wafer, for a 200 mm wafer of 0.7 mm thickness with a Young's modulus of 190 GPa. In this estimate, the applied vacuum pressure was 0.5 bar where the E-pin force applied was 12 N. In this situation it was found that when pressure is kept at 7 mbar, the wafer will just release from the second last burl ring 9 while still being supported by the final burl ring 10 , hence form a stable condition. Between 7 and 3.5 mbar, the wafer will rotate about the outer support point. At 3.5 mbar, the vacuum pressure will have become to low to keep the wafer pushed onto the last burl. The wafer will then release from the table, and the E-pin force will become equal to the wafer weight. To find a quantitative measure for wear energy, the following information is needed: normal contact force; slip force, from coefficient of friction and normal contact force; and slip distance from wafer rotation.
[0057] For an applied e-pin force of 12 N, the wafer edge contact force on the last burl ring was found to be also 12 N at the start of the bowl shape part of the process. The wafer rotation at the end of the bowl shape was found to be 5 mrad. The coefficient of friction is assumed to be 0.2 here. FIG. 7 shows the relation between contact force and wafer rotation: while the wafer rotates to 5 mrad, the contact force drops from 12 N to zero. At 1 mm outside the last burl ring, the wafer will deflect over 5 um for a 5 mrad rotation. With the vacuum seal at 3 um below the burls, the vacuum seal will become point of contact at 60% of the rotation process. It may be appreciated that varying the height of the outer rim will affect the amount of energy that is transferred on either the outer ring of burls 10 or the sealing rim 11 . Hence, in the example where the sealing rim 11 is 3 um below the outer ring of burls 10 , 60% of the friction energy is consumed by the outer burl ring 10 , and 40% is consumed by the sealing rim 11 .
[0058] In a routine for calculating the friction energy for a 6 N e-pin scenario, it is found that the amount of energy spent on the outer rim 11 is zero, while the energy absorbed by the outer ring of burls 10 is only 25% of the energy generated by 12 N, indeed the energy is quadratic in relation to the force applied. A series of adaptations was calculated, wherein, among others, parameters were varied such as the height of the outer rim, the presence of a protective rim element 13 , and applied force.
[0059] The results are summarized in the following table:
Estimated wear energy [fraction of 2.05 uJ] (for a 0.2 friction coefficient) Outer burl Sealing Protective Description of design ring rim rim Total 12 N E-pin force, sealing rim 84% 16% — 100% 5 um lowered, 6 N E-pin force, sealing rim 25% 0% — 25% 1 um lowered, 12 N E-pin force, sealing rim 35% 65% — 100% 1 um lowered, Protective rim, 1 um lowered, 12% 88% 100% 3 mm outside last burl
[0060] From this table, it is apparent that a number of design steps can be taken in order to release said substrate from said holder with a release force acting on the substrate holder, more specifically on the holding region for holding the wafer in a flat position, that is reduced prior to final release. In a practical production process, said release forces and/or said release heights may be determined in-process in an iterative way. In this way, in a high-throughput photolithographic process, the amount of releasing force to be applied to the wafer can be easily and quickly found without causing unnecessary damage to the wafer holder. Furthermore, said release force and/or said release height may be determined based on recently in-process applied release forces and/or release heights. For example, in a batch process, wherein a batch of wafers is ejected from the wafer holder in a subsequent photolithographic process, the method may comprise an ejection routine that ejects the wafers based on the average release force of the last recent results. Such recent results, for example, a statistical averaging of the last ten results, will offer the best heuristic values, while keeping the damage to the wafer to a minimum. In this way, only exceptionally will a more than average release force have to be applied in a subsequent iterative step, for example a preset maximum release force, in order to release a wafer that is clamped to the wafer holder with a more than average clamping force, for instance, due to sticking or other non-average circumstances.
[0061] In this way, the average excess friction energy applied during release of the wafer can be lowered for batch processes, thus reducing the wear on the substrate holder significantly.
[0062] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The description is not intended to limit the invention.
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A lithographic projection apparatus having a radiation system for providing a projection beam of radiation; a support structure for supporting a patterning device, the patterning device serving to pattern the projection beam according to a desired pattern; a substrate holder for holding a substrate the substrate holder provided with a device to provide a holding force for pressing the substrate against the substrate holder; a releasing structure constructed and arranged to eject the substrate from the holder against the holding force; and a projection system for projecting the patterned beam onto a target portion of the substrate. The lithographic projection apparatus may include a controller for controlling the releasing structure so as to release the substrate from the holder with a release force that is reduced prior to final release.
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FIELD OF THE INVENTION
The invention relates to a formwork table arrangement comprising a formwork table and a plurality of supports each of which is downwardly pivotably and removably mounted via a transition support member, which is preferably releasably secured to a head end of the respective support, to a counter-support member, which is preferably releasably secured to a lower side of the formwork table.
PRIOR ART
Formwork table arrangements of the kind described above are known in various embodiments (DE-OS-2648281; DE-OS 2900305; DE 3843336 C1). The essential problem with such formwork table arrangements lies in the fact that the supports must be connected to the support framework stiffening the formwork table in a manner which is relatively stiff in bending. However, after the dismantling of the support from the formwork table, a situation should be achieved in which, so far as possible, no components project downwardly beyond the formwork table. This makes it possible to achieve a low stack height when a plurality of formwork tables are stacked on top of one another during transport on trucks or during storage.
OBJECT OF THE INVENTION
The object of the present invention is to provide a formwork table arrangement of the initially named kind in which the downwardly swung supports which carry the formwork table are connected to the formwork table or its support framework in a manner which is particularly stiff in bending, with it simultaneously being ensured, when the supports are removed from the formwork table, that any components which are provided for the connection to the supports project at most by a minimal amount below the lower boundary of the formwork table or of the support arrangement stiffening it.
BRIEF DESCRIPTION OF THE INVENTION
In order to satisfy this object, a formwork table of the initially named kind is provided in which engaging means are provided at the transition support member and at the counter-support member by means of which the transition support member can be engaged with or suspended from the counter-support member, in particular pivotably engaged or suspended from the counter-support member, preferably in a state tilted relative to the vertical, and in which latching means are provided by means of which the transition support member tilted into the working position can be latched to the counter-support member. It is particularly preferred when the support members are respectively terminated at the top and at the bottom by support plates. Thus, the transition support member and the counter-support member each have a preferably generally rectangular support plate which extends at least substantially parallel to the formwork table in the working position, with the support plates contacting one another in the working position and being preferably pressed against one another by the engaging or latching means.
In this manner it is possible to engage the supports, which are connected to the transition support members, into the counter-support members, which are connected firmly to the formwork table, while the supports are in an inclined position. Thereafter, the supports can be pivoted without problem relative to the counter-support members into the vertical position and finally latched firmly to the counter-support members. Since all the components of the counter-support members can be accommodated within the support framework of the formwork table, and since only the lowermost part of the counter-support member formed by a support plate projects downwardly beneath the support framework, in particular beneath the reinforcing or truss beams of the formwork table, the thickness of the formwork table is only minimally increased by the counter-support members of the invention, as secured to the formwork table. Accordingly, the stack height of a plurality of formwork tables stored one above the other is only increased in negligible manner relative to formwork tables without counter-support members.
Since the support plates can be connected as rigidly as desired to the support framework of the formwork table and to the upper end of the components which act at the upper end of the supports, via correspondingly stable intermediate components, the bending stiffness which is achieved by the mutual engagement and latching of the support plates is extremely high. Despite the minimal stack height of the formwork table of the invention, both simple engagement and also pivoting of the supports is possible without problem and an ideal bending stiffness is ensured in the latched state. The design of the invention also makes it possible to arrange two truss beams closely alongside one another in each case and to associate a single counter-support member with these double beams.
In accordance with the invention the transition support member is preferably primarily firmly connected to the upper region of the supports, so that the generally present head plate of the supports at most only secondarily participates in the mounting of the supports in a manner stiff in bending.
The possibility of engaging and latching the supports to the counter-support members from below means the installation and dismantling of the supports at the formwork table can be achieved without the fitter having to climb up to the top of the supports.
The provision of the actuating lever has the advantage that the delatching can be carried out from below by means of a bar or the like in that the actuating hoop is simply pushed upwardly. On the other hand, the latching can expediently simply take place in such a way that the actuating hoop pivots downwardly as a result of the weight force, and thus brings the latching lever into engagement with the associated support plate.
The hooks are preferably mounted on the upper support plate and the hook holders on the lower support plate, as defined in claim 16.
By providing numerous bores alongside one another in the carrier beams, the counter-support members can be secured at numerous different positions between transverse beams. In just the same way the carrier beams, which form a frame with the attachment brackets, can be mounted at any desired positions between two neighboring transverse beams, so that the counter-support members can practically be mounted at any desired position at the lower side of a formwork table.
The supports normally have head plates at the top and at the bottom. In this case provision should be made that the upper head plates contact the underside of the support plates of the transition support member. In this manner, the head plates participate in a mounting of the supports in a manner which is stiff in bending without being overloaded.
Another embodiment provided that the latching process takes place automatically on pivoting the support out of the tilted engagement position into the working position,
If desired the latching levers automatically snap into the latched position.
BRIEF DESCRIPTION THE DRAWINGS
The invention will be described in the following by way of example and with reference to the following drawings:
FIG. 1 is a perspective view of a formwork table arrangement in accordance with the invention seen obliquely from below,
FIG. 2 is a perspective enlarged view of a carrier frame in accordance with the invention,
FIG. 3 is an enlarged perspective view of a counter-support member in accordance with the invention,
FIG. 4 is a similar perspective view of a transition support member in accordance with the invention,
FIG. 5 is a perspective view of the assembly of a carrier frame in accordance with the invention, of a counter-support member in accordance with the invention and of a transition support member in accordance with the invention, with the formwork table and the associated supports not being shown for the sake of simplicity,
FIG. 6 is a view of the same subject as in FIG. 5 but essentially from the opposite direction and in a somewhat different perspective, and
FIG. 7 is a schematic side view of a section of a formwork table arrangement in accordance with the invention in the working position showing the essential components.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with FIG. 1 a formwork table 13 comprises a formwork skin 42, transverse beams 33 arranged at the underside of the formwork skin parallel to one another at the same spacing, and also truss beams 34 arranged beneath the transverse beams 33 perpendicular to the latter. The truss beams can also consist, in each case, of two closely arranged single beams. In this manner, a stable formwork table 13 is formed which is also suitable for receiving larger quantities of concrete.
The formwork table 13 is carried by four telescope supports 11 which stand at the bottom on a non-illustrated foundation and are terminated at the top by head plates 39 which extend perpendicular to the support axis. In their upper end region the supports 11 are fixedly connected to a transition support member 12. This is in turn releasably mounted on a counter-support member 14, which is so arranged and clamped between the transverse beams 33 and the truss beams 34, by means of carrier elements 31 and carrier beams 32, that it forms a fixed component of the formwork table 13.
In accordance with FIGS. 2, 5 and 6, two carrier beams 32 are in each case secured parallel to one another to attachment brackets 35 extending perpendicular to them. The length of the carrier beams 32, i.e. the spacing of the two connection brackets 35 which complement the two carrier beams 33 into a carrier frame 41, is such that it corresponds to the spacing of two transverse beams 33, so that the carrier frame 41 of FIG. 7 just fits between two adjacent transverse beams 33 and can be secured to the latter above the truss beam 34 by means of bores 43 and non-shown screws. The connection brackets 35 are preferably formed in the illustrated manner by angle sections of which one limb can, in accordance with FIG. 7, lie on the lower spar 44 of the transverse beam 33, whereby a problem free and particularly stable mounting of the carrier beams 32 on the transverse beams 33 is ensured.
The carrier beams 32 are themselves formed as U-sections open towards one another and have a plurality of throughgoing attachment bores 36 at uniform intervals.
In FIG. 3 the counter-support member 14 is shown which is to be secured at the bottom to the carrier beams 32 of FIG. 2 and which--as one can also see from FIGS. 5 to 7--comprises a flat, horizontal counter-member support plate 16, two cheeks 19 which project vertically upwardly from its longitudinal sides, and vertically upwardly projecting carrier elements 31. The carrier elements 31 are formed by a lower T-section 38 and by respective vertical bolts 37 secured to their upper end region, which are introduced during the later assembly in accordance with FIGS. 5, 6 and 7 into a respective pair of bores 36 lying above one another of the carrier beams 32. Thereafter, in accordance with FIG. 7, clamping nuts 45 are screwed onto the bolts 37 which are provided with a thread at the top. The bolts 37 must therefore be provided with a thread, at least in their upper end region.
The cheeks 19 are formed in the manner which can be seen from FIGS. 3, 5 and 6 in the manner of a flat triangle with a rounded off upper tip and have substantially upwardly extending hooks 17 at their ends located in the region of the short sides of the support plate 16. The support plate 16 extends on both sides approximately up to the level of the hooks 17 and has right-angled cut-outs 23 directly alongside the hooks 17.
In accordance with FIGS. 3, 5 and 6, central and downwardly rounded cutouts 52 are provided in the side cheeks 19 of the support plate 16 of the counter-support member. In this manner, T-sections 38 can be better welded at the bottom.
The T-sections 38 are vertically arranged on the central transverse axis of the support plate 16, and indeed in such a way that the T-center web contacts the inner side of the cheeks 19 and is welded there. The bottom sections 38 stand up on the support plate 16 and are also preferably welded there. The transverse webs of the T-section 38 face one another and are parallel to one another. Their spacing is so selected that a double truss beam 34 just fits between them, as one can see from FIG. 1. As a result of the described arrangement, the counter-support member 14 in accordance with FIG. 1 can be pushed from below onto a double truss beam 34, with the vertical carrier elements 31 projecting upwardly between two cross beams 33, where a carrier frame 41 in accordance with FIGS. 2, 7 is secured, the bolts 37 passing through two of its pairs of bores 36. The spacing of the carrier beams 32 of the carrier frame 41 thus corresponds to the spacing of the bolts 37.
In accordance with FIG. 7, a clamping nut 45 is screwed from above onto the bolts 37. In this way the support plate 16 of the counter-support member is drawn from below against the double truss beam 34 and fixedly clamped against the latter. The transverse webs of the sections 38 thereby contact the truss beam 34 at the side. In this manner, the arrangement of the invention consisting of the carrier frame 41 and the counter-support member 14 also substantially contributes to the stability of the subframe of the formwork table 13. Decisive for the invention is, however, the fact that the counter-support member 14 practically only projects downwardly beyond the truss beam 34 by the thickness of the support plate 16 of the counter-support member. Since the thickness of the support plate 16 only amounts to approximately 8 mm, the downward projection beyond the formwork table 13 is thus practically negligible. For the lowest possible projection of parts of the counter-support member 14 downwardly beyond the truss beam 34 it is also important that the cheeks 19 including the hooks 17 only project upwardly from the support plate 16 and do not project downwardly.
FIG. 4 shows the transition support member 12 of the invention which, in accordance with FIG. 1, is in each case firmly connected to the top end region of one support 11 and is so designed that it can be releasably but fixedly firmly connected with the counter-support member 14 of FIG. 3 from below.
The important component of the transition counter-member 14 is a horizontal flat support plate 15 of a thickness of approximately 6 mm which is made somewhat broader and shorter than the support plate 16 of the counter-support member in accordance with FIG. 3. Cheeks 20 are bent upwardly at the longitudinal sides of the support plate 15. The spacing of the cheeks 20 is so selected that when the transition support member 12 contacts the counter-support member 14, the cheeks 20 in accordance with FIGS. 5, 6 come into contact with the outer side of the triangular cheeks 19 of the counter-support member 14. The cheeks 20 are substantially lower than the cheeks 19 and have an upper edge 20' which extends parallel to the plane of the support plate 15.
At the rear end region of the cheeks 20 in FIG. 4, hook holders 18 project inwardly at a distance from the support plate 15 and are formed on obliquely upwardly bent brackets 22 of the support plate 15 which project at a narrow side of the plate.
Whereas a pair of hooks 17 is provided at the counter-support member 14 at each of the two ends of the support plate 16, and is designed with mirror symmetry to the other pair of hooks 17 with respect to the central transverse axis 21, the lower support plate 15 only has a pair of hook holders 18 at its one end. Between the obliquely upwardly bent brackets 22 and the associated cheeks 20 a slot 46 is provided beneath the hook holders 18 with the size of the slot being so dimensioned that a hook 17 can be introduced there.
In accordance with FIGS. 4 and 5, a holder 29 is mounted, preferably by welding, on the support plate 15 of the transition counter-member at the bottom and has a substantially U-shaped horizontal cross-section. At its closed side, the holder 29 has a vertically extending prismatic recess 47 of dimensions such that supports 11 of different cross-section (round, angular) and different dimensions can be received therein. For the fixation of the upper end regions of the supports 11 inserted there, two clamps 30 arranged above one another are also provided on the holder 29. The clamps can clamp the inserted upper end region of the support 11 against the recess 47 by bolts 48 which are only indicated (see also FIG. 6), so that the holder 29 practically forms a fixed component of the support 11. The clamps 30 are also selected in cross-section so that they fix supports of different cross-sectional shapes and sizes at the holder 29.
Two latch levers 24 are pivotally arranged on the holder 29 about a transverse axis 26 and each has a latch 25 above the pivot axis 26 which engages over the support plate 15 when the latch lever 24 is pivoted upwardly, as can be seen in FIG. 4.
The two latch levers 24 are firmly connected together by an actuating hoop 27 which extends around the holder 29 on the far side of the transverse axis 26. In this manner, the latch levers 24 are pivoted by the weight of the actuating hoop 27 into the position which can be seen from FIG. 4, providing the transition support member 12 is vertically arranged as is illustrated in FIG. 4.
At their upper side, the latches 25 have a latching ramp 40, the significance of which will be explained further below. It is important that the latching levers 24 can each be biased into the latching position shown in FIG. 4 by some form of resetting force, which can also be obtained with a resetting spring.
The dimensioning of the individual components of the transition support member 12 can be deduced from the following functional description.
After, for example, four carrier frames 41 have been secured to the lower side of the formwork table 13 in accordance with FIG. 1, together with the counter-support member 14 in the manner described above, and after a transition support member 12 in accordance with FIG. 4 has been secured by means of the clamps 30 to the top of each of the supports 11 that are used, the supports 1 1 can be installed on or dismantled from the formwork table 13 in the following manner:
First of all the formwork table 13 which is already provided with the carrier frames 41 and the counter-support members 14 is held at a specific level, for example by a crane, which is larger than the length of the supports 11 to be attached.
An operator can now in each case take a support 11 provided at the top of a transition support member 12 in his hand and guide the hook holders 18 over a pair of hooks 17, with the support 11 more or less inclined, and with the hooks 17 passing through the slots 46 (FIG. 4). As soon as the hooks 17 have been passed through the slots 46 the operator can relieve the relevant supports 11 somewhat, whereupon the hook holders 18 engage into the recess 49 (FIG. 3) located behind the hooks 17.
The support 11 and the counter-support member 14 are now already adjusted relative to one another in problem free manner. The operator pivots the supports 11 downwardly into the vertical position, with the latches 25 which are located in the position of FIG. 4 engaging into the cut-outs 23 of the support plate 16 of the counter-support member and with their latching ramps 40 abutting against the associated edge 50 (FIG. 3) of the support plate 16 at the base of the cut-outs 23. As a result of a suitable angle of the latching ramps 40 relative to the horizontal, a force is produced which presses the latch levers 24 away from the edge 50, so that the latch 25 is pivoted into its unlatched position and can finally slide past the edge 50 into the region above the support plate 16 of the counter-support member. As soon as this is the case, the weight force which is brought about by the actuating hoop 27 causes the latch 25 to pivot over upper latching counter surfaces 28 provided on the support plate 16 behind the cut-outs 23 and its lower counter surface 51 (FIG. 4) comes into engagement there. In this way, the support plates 15, 16 are fixedly clamped against one another. The latching engagement can be further enhanced if required by pulling on the actuating hoop 27. The end state of the latching of the support plates 15, 16 to one another can be seen from FIGS. 5, 6 and 7.
Depending on the direction in which the supports 11 are swung away from the upper support plate 16, the one or other pair of hooks 17 of FIG. 3 can be used for the engagement with the hook holders 18. In this manner, it is possible to attach the supports 11 to the counter-support member 14 in two positions rotated through 180° about their axes.
The separation of the supports 11 from the formwork table 13 then takes place in that the actuating hoop 27 (FIGS. 4, 5, 6, 7) is pushed upwardly, for example by means of a rod, whereby the latches 25 come free from the upper support plate 16. Thereafter, the support 11 can be pivoted about that pair of hooks 17 on which the lower support plate 15 is suspended. The latch levers 25 are pivoted downwardly during this and can thus come fully out of engagement with the upper support plate 16. The supports 11 can be pivoted up to and into the horizontal for transport but must be secured in a suitable manner to the formwork table 13 if they are to remain on the formwork table 13 during transport, so that no disengagement of the hook holders 18 occurs. However, should the supports 11 be transported separately from the formwork table 13, as is preferred, a simple disengagement of hook holders 18 from the hooks 17 can take place.
Thereafter, the formwork tables are available for transport with practically no projection of components downwardly. Because a projection of the counter-support members 14 downwardly has been dispensed with, a minimum stack height can thus be achieved during transport.
An important aspect of the invention lies in the fact that the head plate 39 of the supports 11, which can be seen in FIG. 7, admittedly makes a certain contribution to the mounting of the support 11 at the formwork table, in a manner stiff in bending, by contact at the lower side of the support plate 16 of the counter-support member. However, the important introduction of force into the supports 11, or from the supports 11, takes place via the attachment of the entire upper end region of the supports 11 in the holder 29 by means of the clamps 30.
The high bending stiffness of the arrangement of the supports 11 at the formwork table 13 is primarily achieved by the close contact of the support plates 15, 16. The form-fitted contact between the transition support member 12 and the counter-support member 14 brought about by the design in accordance with the invention is also of importance. The lateral form-fitted connection of the two support plates 15, 16 is achieved by the contacting of the cheeks 19, 20, while the form-fit in the longitudinal direction is achieved by the engagement of the hooks 17 on the hook holders 18 and the contact of the base of the groove 54 (FIG. 5) between the latch lever 24 and the latch 25 at the oppositely disposed edge 50 (FIG. 3) of the support plate 16.
The regions of the support plate 16 between the cut-outs 23 (FIG. 3) favor the lateral form-fitted connection of the two support members (12, 14) after the installation, because in this region a lateral contact arises against the bent brackets 22 and the latches 25.
Since the different types of supports 11 which are available can each be provided at their upper end with the same transition support member 12, a standardization arises independent of the supports, in such a manner that the most different types of supports can be used for the purpose of the invention.
On the one hand, the carrier frames 41 of the invention and the support counter-members 14 of the invention can ultimately be secured to any desired formwork table 13 or its subframe 33, 34. The invention thus ensures not only an easily installable and easily releasable and particularly stiff arrangement of the supports 11 at the formwork table 13, but rather also an extremely universal use for the most different types of supports 11 and formwork tables 13.
In order to achieve good bending stiffness it is advantageous when the support plates 15, 16 are made relatively large. Their dimensions can for example amount to ca. 15 cm×25 cm. The width of the support plates 15, 16 is ultimately predetermined by the width of the double truss beam 44, which is largely normed and standardized with the formwork techniques under discussion here.
In accordance with FIG. 6 obliquely extending sheet metal supports 53 can be arranged in accordance with the invention between the support plate 15 of the transition support member and the holder 29 and are welded to the support plate 15 and to the holder 29. In this way, the bending stiffness of the arrangement is further increased.
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A formwork table arrangement having a formwork table (13) and a plurality of supports (11) each of which is downwardly pivotably and removably mounted via a transition support member (12), which can be releasably secured to a head end of the respective support, to a counter-support member (14) that is releasably attached to a lower side of the formwork table. Hooks and hook holders (17, 18) are provided at the transition support member (12) and at the counter-support member (14) which permit suspension of the transition support member (12) from the counter-support member (14). A latching arrangement (24, 25, 28) enables the latching of the transition support member (12) to the counter-support member (14) when tilted into the normally upright working position.
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BACKGROUND OF THE INVENTION
This invention relates generally to a fluid activated percussive impact tool having a piston reciprocal in a housing of such tool, and more particularly to a lubrication system for a jackhammer in which the piston is longitudinally reciprocal and the drill steel is rotated as well as impacted by the piston.
Typical lubrication systems on handheld jackhammers and paving breakers incorporate an oil reserve chamber and some type of metering device. The reserve chamber is generally connected to the high pressure air supply. High pressure air enters the chamber until the chamber reaches the pressure of the supply. Once the supply pressure is relieved, any oil that may be in the chamber will meter back into the high pressure supply line. Once the high pressure chamber is re-pressurized, any oil in the line is then carried into the tool to help lubricate the running components. The metering device to prevent large quantities of oil from escaping the oil reserve can be a complex metering device or a simple sintered, porous filter element. Even with the oil being metered, the oil volume entering the tool is often more that the tool requires for proper operation.
The foregoing illustrates limitations known to exist in present jackhammers. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
SUMMARY OF THE INVENTION
In one aspect of the present invention, this is accomplished by providing a low pressure lubricating system having a lubricant chamber for storing a liquid lubricant in a bore of a jackhammer, means for introducing a liquid lubricant into the lubricant chamber, means for subjecting the lubricant chamber to low fluid pressure in a front piston chamber, and passageway means between the lubricant chamber and the bore, for introducing lubricant into the bore during operation of the jackhammer.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is cross sectional view, with parts removed, of a prior art piston rotated by a ratchet and pawl mechanism;
FIG. 2 is a view along lines A--A of FIG. 1;
FIG. 3 is a cross sectional view of the jackhammer of this invention;
FIG. 4 is an expanded view of the removable clutched spline nut and oil lubrication system of this invention;
FIG. 5 is view along lines B--B of FIG. 4;
FIG. 6 is an isometric view of a removable splined nut for use in this invention;
FIG. 7 is an expanded view in circle A of FIG. 4; and
FIG. 8 is perspective view of a piston stem showing the longitudinal and helical grooves.
DETAILED DESCRIPTION
While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that other variations and changes may be made therein without departing from the invention as set forth in the claims.
Referring to FIGS. 1 and 2, the prior art jackhammer having a mechanism for rotating the piston during the stroke cycle is shown. Piston 1 is mounted on rifle bar 3 by means of piston rifle nut 5 that is threadably connected to piston head 7. Piston rifle nut 5 is slidably mounted on rifle bar 3 by means of internal splines that match longitudinal grooves 9 that extend along rifle bar 3 in the same longitudinal direction as the reciprocation of piston 1.
Top end 11 of rifle bar 3 is connected to a ring gear 13 by means of a plurality of pawls 15 that interact with ring gear 13 to permit rotation in only one direction. Ring gear 13 is positioned in the backhead portion of the jackhammer housing (not shown) along with valve 17 that distributes percussive fluid to the drill during the operation thereof.
Piston stem 20 is supported in housing 22 for reciprocation along longitudinal axis 24 by piston stem bearing 26. Chuck nut 28 is slidably mounted on piston stem 20 by means of internal splines that match longitudinal grooves 30 that extend along piston stem 20. Chuck nut 28 is threaded into chuck driver 32, that is, in turn, connected to chuck 34. Drill steel 36 is slidably mounted into chuck 34. Thus, it can be understood, that in the prior art jackhammers, the piston 1 reciprocates back and forth in a longitudinal direction, while at the same time, it rotates in one direction. This rotational movement is translated to drill steel 36 by means of the connection between piston 1 and piston rifle nut 5, and splined chuck nut 28 that is, in turn, connected to chuck driver 32, and chuck 34.
Referring to FIG. 3, the jackhammer of the invention is shown generally as 40 having an outer housing 42 through which extends a central bore having a longitudinal axis 44 for reciprocation of a piston 46 and a drill steel 48, 100, as is conventional. Piston 46 is actuated by a percussive fluid, such as compressed air at a pressure of about 90 to 100 psig. Piston 46 comprises a piston head 48, a piston tail 50 on one side of piston head 48, and a piston stem 52 on an opposite side of piston head 48. Piston 46 is supported for longitudinal reciprocation in housing 42 by housing body member 54 contacting piston head 48, air distributor 56 contacting piston tail 50 and piston stem bearing 58 contacting piston stem 52, as is well known.
Percussive fluid is introduced into accumulator chamber 60 in backhead 62, and is directed by distributor 56 to fluid passageways 64, 66 and ports 68, 70 to a drive chamber 72 and thereafter to a return chamber 74. Depending upon the position of piston 46 in the stroke cycle, either drive chamber 72 or return chamber 74 is opened to exhaust port 76, to exhaust the fluid in the respective chamber, 72 or 74.
The piston 46 is grounded from rotary motion through a series of longitudinal grooves 80 that extend downwardly along piston stem 52. As used herein, the terms "longitudinal" or "longitudinally" mean in a direction that is parallel to axis 44. Grooves 80 mate to splines 82 in a removable splined nut 84 that is non-rotatable, with respect to its surrounding housing 86 (FIG. 5). Splines 82 are formed in an inner surface of nut 84 and extend longitudinally downwardly along the length of nut 84.
The piston 46 also has a series of helical grooves 90 (FIG. 8) which are connected to helical splines 92 in a helical nut 94. Helical grooves 90 extend downwardly along piston stem 52 and are located between a said longitudinal grooves 80, preferably one helical groove 90 between each pair of adjacent longitudinal grooves 80. The helical action of the splines 82 causes the helical nut 94 to oscillate rotatably back and forth as the piston 46 reciprocates. The helical nut 94 is then frictionally attached to a uni-directional clutch mechanism, such as a wrap spring clutch 96, which drives the chuck 98 and drill steel 100. Helical nut 94 is provided with an external surface that has a first hub surface 102 thereon. Chuck 98 is positioned in the bore so that a second external hub surface 104 on chuck 98 is provided adjacent to first hub surface 102. A helical spring 106 is wrapped around both first and second hub surfaces 102, 104, so that as piston 46 reciprocates, the chuck 98 and drill steel 48, 100 therein, rotate in one direction. The wrap spring clutch mechanism is described in U.S. Pat. No. 5,139,093, issued to Leland H. Lyon et al.
Splined nut 84 is removable from housing 86. Removability is provided by eliminating the prior art threaded connection between nut 5 and piston head 7, that is shown in FIG. 1, and providing the nut 84 with internal splines 82 that engage with mating grooves 80 in piston stem 52, as shown in FIG. 3. Thus, it can be understood that nut 84 is slidably splined on piston stem 52, but is non-rotatable with respect to the longitudinal axis 44, piston 46 and housing 86.
As shown in FIG. 5, the nut 84 has at least one lobe 110 on the outside profile of the nut itself. While I prefer three lobes 110, equally spaced around a circumference of an outer surface of nut 84, any reasonable number will work. Each lobe 110 of this male profile of the nut 84 engages a female type lobe cavity 112 in the surrounding housing 86. The piston 46 reciprocates as the drill operates. The wrap spring clutch 96 influences the piston 46 to rotate. The function of the nut 84 is to prevent this rotation. As the piston 46 tries to rotate, the splines 82 of the nut 84 resist the rotation. The torsional load is then transmitted to the lobes 110 and lobe cavities 112 of housing 86, thus preventing rotation.
As shown in FIGS. 6 and 7, tapering of the outside diameters of the nut 84 further assists in the ability of the nut 84 to carry the load. The nut 84 is tapered such that, when viewed in a cross sectional view, the entire male profile is smaller at the top end 114 and bottom end 116 of nut 84 than at the center portion apex 118 between the top and bottom ends 114, 116, respectively, of the nut. As the nut 84 is inserted into the female housing profile, the nut 84 pinches the housing 86. Thus, it can be understood that there are provided two interference fits: the first one by the lobes 110 and a second one by the tapered body of the nut.
In addition, a third interference fit can be provided by forming in one or more lobes 110 a longitudinal groove 120 extending axially lengthwise along the length of nut body 84. I prefer to provide a groove 120 in each of the three lobes 110. A pin 122 is mildly pressed into each groove 120 for a force fit between the nut 84 and the lobe cavity 112 of housing 86. As the other two interfaces wear away, the pin arrangement will act similar to a roller ramp type clutch which would further pinch the geometry as the nut begins to rotate.
Lubrication for the jackhammer is provided by introducing a liquid lubricant, preferably oil, into the percussive air. Oil cap 130 threadably closes an oil inlet tube 132 in housing 86, as shown in FIGS. 3 and 4. The operator of the jackhammer introduces oil into inlet 132 at periodic intervals. Piston stem bearing 140 has an internal surface 142 that slidably contacts piston stem 52, and supports piston 46 for reciprocation along axis 44. Piston stem bearing 140 has an external surface 144 that forms an annular recessed portion 146 and a bottom flanged portion 148. Annular recess portion 146, at an upper land surface 150, contacts housing internal wall 152, in a fluid sealing contact. The combination of external surface 144 and housing 152 form an oil chamber 160. Oil chamber 160 can also be formed , in part or in whole, by a recess in an internal surface of housing 152. Oil chamber 160 communicates with inlet tube 132, to carry oil into chamber 160. An oil feed aperture 170 extends through bottom flange 148 and forms an internal recess for a metering element 172, such as a removable, porous, sintered, metallic plug. Oil feed aperture 170 and metering element 172 provide a passageway for oil to enter into the bore of the jackhammer in the area of the removable splined nut 84. Bottom flange 148 also contacts the internal wall of housing 86 in a fluid sealing contact.
Top end 180 of piston stem bearing 140, in a location that is spaced above upper land surface 150, contacts the internal surface 182 of housing 86 in a second fluid sealing contact. Between top end 180 and upper land 150 is a first circumferential groove 184 in external surface 144 that communicates with a second circumferential groove 186 in internal surface 142 of piston stem bearing 140 by way of a plurality of holes 188 spaced circumferentially around piston stem bearing 140. First groove 184 communicates with an external passageway 190 provided for flushing fluid to pass into front piston chamber 192 and out around drill steel 48,100, by way of holes 188 in bearing 140 and grooves 90 in piston stem 52, for flushing debris from the drillhole. The external passageway 190 and grooves 184, 186, plus holes 188 are optional and form no part of this present invention.
In operation, as the return chamber 74 exhausts, a portion of the exhaust enters the front piston chamber 192 in front of piston 46, by way of longitudinal grooves 80 in piston stem 52. There, such exhaust combines with percussive fluid transmitted down through the center of piston 46 from air distributor chamber 60 in the backhead of the jackhammer. The oil and fluid mixture lubricates the wrap spring clutch 96 and other working surfaces in that area, and eventually is exhausted out around the drill steel, to remove debris from the drillhole.
The pressure in this front chamber 192 is usually 10-30 psig, while the pressure in drive chamber 72 and return chamber 74 is much higher, about 90-100 psig. Because oil chamber 160 is positioned below return chamber 74 and not in fluid contact with the pressure therein, oil chamber 160 is only subject to the lower pressure differential caused by the lower pulsing pressure of front piston chamber 192. This lower pressure differential results in less oil being consumed from oil chamber 160.
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A percussive, fluid-activated jackhammer includes a low pressure lubrication system having a liquid lubrication reservoir chamber formed in a bore of the jackhammer, the lubrication chamber being subject to low percussive fluid pressure in a front piston chamber but not to high percussive fluid pressure in a drive or return chamber of the device. An inlet passageway is provided for adding lubricant to the lubricant chamber. An outlet passageway is provided, with a metering device therein, for flow of lubricant into the bore of the device during reciprocation of a piston in the bore.
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TECHNICAL FIELD OF THE INVENTION
This invention relates in general to a device that facilitates accurate aiming of a firearm and, more particularly, to a firearm sight that is mounted on the firearm, and through which a user observes a potential target.
BACKGROUND OF THE INVENTION
Over the years, various techniques and devices have been developed to help a person accurately aim a firearm, such as a rifle or a target pistol. One common approach is to mount a sight or scope on the firearm's barrel. A person then uses the sight or scope to view an intended target in association with a reticle, often with a degree of magnification. Although existing firearm sights of this type have been generally adequate for their intended purposes, they have not been satisfactory in all respects.
For example, some pre-existing sights have included the capability to record an image showing a target and/or a reticle, and to later display one or more of these recorded images. However, when these recorded images are displayed, it is possible for a safety hazard to occur. For example, if the recorded image is presented on an electronic display that is separately used to show actual targets, a user may mistake the recorded image for an actual target, and may then discharge the weapon in the belief that he or she is shooting at something in the recorded image, when the weapon is actually pointed at some other person or thing. Moreover, even if the user does not intentionally discharge the weapon while viewing recorded images, there is always a risk of accidental discharge. Consequently, if the user is distracted while viewing recorded images, or gives the weapon and sight to another person who is distracted or who is not familiar with weapon safety, the weapon may be inadvertently pointed in a direction that presents a safety hazard.
A different consideration is that hunting regulations in most states stipulate that hunting is allowed only during the time from one-half hour before sunrise to one-half hour after sunset. The intent of these regulations is to prevent the unsafe practice of shooting in very low light levels, where the actual identity of a target may be questionable. The level of illumination at one-half hour before sunrise and at one-half hour after sunset is sometimes referred to as “civil twilight”, and falls in a luminance range of 0.1 to 1.0 foot-candles. This luminance range corresponds to a cloudless sky. Other conditions can cause the illumination level to drop below that of civil twilight at almost any time during the day, for example where there is a dense cloud cover, or where a hunter is in a dense forest. There is no easy way for hunters and game wardens to determine actual levels of illumination, and this is why states have adopted the compromise approach of defining allowable hunting conditions in terms of dusk and dawn, rather than in terms of actual levels of illumination. Existing sights provide hunters with no assistance in detecting or avoiding actual low light conditions that can present potential safety hazards.
Still another consideration is that virtually all states have a hunting regulation that requires hunters to wear a fluorescent orange garment above the waist while hunting. This color does not occur naturally in any big game animals, or in their environment. The fluorescent orange color is thus intended to be a visual cue to a hunter that a person is present, rather than a potential animal target. Even where such a garment is present, the patch of orange color may be partly obscured by other objects in the scene, or may be very small if the hunter is a significant distance from the person wearing the garment. In either case, the presence of the orange color in the scene may be inadvertently and unintentionally overlooked by a hunter, resulting in a potentially dangerous situation for the person wearing the garment. Existing rifle sights provide hunters with no assistance in detecting fluorescent orange to avoid potentially dangerous hunting situations.
SUMMARY OF THE INVENTION
According to one aspect of the invention, a method and apparatus relate to a weapon-mountable sight having a display and involve presenting selected information on the display only when a detector portion indicates that the sight has an orientation that meets an orientation criteria.
According to a different aspect of the invention, a method and apparatus relate to a weapon-mountable sight and involve: using a detector portion to determine a level of ambient illumination external to the sight; and taking a selected action in response to a determination that the level of ambient illumination is less than a selected level of illumination.
According to still another aspect of the invention, a method and apparatus relate to a weapon-mountable sight, and involve taking a selected action in response to detection of a selected color within radiation originating from externally of the sight.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention will be realized from the detailed description that follows, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a diagrammatic perspective view of an apparatus that is a digital rifle sight embodying aspects of the present invention;
FIG. 2 is a block diagram of the digital rifle sight of FIG. 1 , and shows some internal components thereof;
FIG. 3 is a diagrammatic view of an internal display that is a component of the rifle sight of FIG. 1 , as seen by the eye of a person using the sight;
FIG. 4 is a diagrammatic view of a switch panel that is a component of the rifle sight of FIG. 1 , and that has a plurality of manually operable switches;
FIG. 5 is a diagrammatic view of an external display that is a component of the rifle sight of FIG. 1 , with a recorded image displayed thereon;
FIG. 6 is a diagrammatic view of the internal display while the rifle sight is being used to view a scene having a low level of ambient illumination; and
FIG. 7 is a diagrammatic view of the internal display while the rifle sight is being used to view a scene that includes a person wearing a fluorescent orange garment.
DETAILED DESCRIPTION
FIG. 1 is a diagrammatic perspective view of an apparatus that is a digital rifle sight 10 , and that embodies aspects of the present invention. Although the sight 10 is sometimes referred to herein as a “rifle” sight, it can actually be used not only with rifles, but also with other types of firearms, such as target pistols.
The sight 10 includes a rail support or rail mount 12 that can fixedly and securely support or mount the sight 10 on the barrel of a firearm. The sight 10 has a switch panel 13 , with several manually operable switches that are discussed in more detail later. The sight 10 has an external color display 14 that, in the disclosed embodiment, is a liquid crystal display (LCD) of a type commonly found on digital cameras and video cameras for the purpose of viewing images or video clips that have been stored within these cameras. One end of the sight 10 has an eyepiece section 15 .
FIG. 2 is a block diagram of the rifle sight 10 , and shows some internal components of the sight 10 that are relevant to an understanding of the present invention.
The sight 10 includes an objective lens section 16 of a known type. In the disclosed embodiment, the lens section 16 has a field of view (FOV) of 5°, but it could alternatively have some other field of view. The lens section 16 optically images a remote scene or target 17 onto an image detector 18 . In the disclosed embodiment, the image detector 18 is a charge coupled device array (CCD array) of a known type, and has 1,920,000 detector elements that each correspond to a respective pixel in each image produced by the image detector 18 , and that are arranged as an array of 1600 detector elements by 1200 detector elements. However, the image detector 18 could alternatively be implemented with any other suitable device, including a device having a larger or smaller number of detector elements, or a type of device other than a CCD array, such as a Complementary Metal Oxide Semiconductor (CMOS) image sensor.
The image detector 18 produces a sequence of digital color images of the scene 17 , and this sequence of images is supplied to a control section or processing section 21 . Although the image detector 18 of the disclosed embodiment produces color images, the images could alternatively be monochrome images, or black and white images. The processing section 21 includes a processor 22 of a known type, and a memory 23 . The memory 23 in FIG. 2 is a diagrammatic representation of the memory provided for the processor 22 , and may include more than one type of memory. For example, the memory 23 may include a read only memory (ROM) that contains a program executed by the processor 22 , as well as data that does not change during program execution. The memory 23 can also include some semiconductor memory of the type commonly known as “flash” RAM. A “flash” RAM is a type of memory that is commonly used in devices such as memory cards for digital cameras, and that maintains the information stored therein even when electrical power is turned off.
The processing section 21 further includes a reformatter 26 of a known type. The reformatter 26 is capable of taking an image generated by the image detector 18 , and reformatting the image to a lower resolution that is suitable for presentation on a display having a lower resolution than the image detector 18 . Images processed by the reformatter 26 are selectively supplied to two display driver circuit 30 and 31 . The display driver circuit 30 drives the external display 14 , and the display driver circuit 31 drives an internal color display 32 . The display driver circuits 30 and 31 can be different channels of a single display driver circuit, but are shown as separate blocks in FIG. 2 for clarity. In the disclosed embodiment, the color display 32 is a liquid crystal display (LCD) of a known type, and has 76,800 pixel elements arranged as an array of 320 elements by 240 elements. The display 32 could, however, have a larger or smaller number of pixel elements, or could be any other suitable type of display, such as an organic light emitting diode (OLED) display, a liquid crystal on silicon (LCOS) display, or a micro-electro-mechanical system (MEMS) reflective display.
The eyepiece section 15 ( FIG. 1 ) of the sight 10 includes eyepiece optics 36 of a known type. The eyepiece optics 36 permit the internal display 32 to be comfortably viewed by an eye 37 of a person who is using the sight 10 in association with a firearm. In the disclosed embodiment, the eyepiece optics 36 have an FOV of 15°, but could alternatively have some other suitable FOV. In addition, the eyepiece optics 36 of the disclosed embodiment could optionally be omitted for applications that allow a person to directly view the display 32 with a viewing distance greater than about 8 inches, since comfortable viewing is then possible with little eye accommodation needed.
The sight 10 includes an accelerometer 41 that has an output coupled to the processing section 21 . In the disclosed embodiment, the accelerometer 41 is a device that can be obtained commercially as part number ADXL105 from Analog Devices, Inc. of Norwood, Mass. Although the disclosed embodiment implements the accelerometer 41 with the Analog Devices-ADXL105 device, the accelerometer 41 could alternatively be implemented with any other suitable device. The accelerometer 41 is a micro-electro-mechanical system (MEMS) device, and serves as a highly sensitive sensor that can detect the relatively small shock wave caused when a firing pin strikes a cartridge within a firearm on which the sight 10 is mounted. In addition, as discussed later, the accelerometer 41 is also responsive to the force of gravity.
When a firing pin strikes a cartridge, it triggers combustion of the gunpowder or other propellant within the cartridge, so as to expel a bullet or other projectile from the cartridge and firearm. Consequently, a relatively small shock wave is produced when the firing pin strikes the cartridge, and this small shock wave is promptly followed by a significantly larger shock wave or recoil that is produced by the combustion of the gunpowder and the expulsion of the bullet. The latter shock wave is several orders of magnitude larger than the shock wave produced when the firing pin strikes the cartridge. The accelerometer 41 has the sensitivity and bandwidth needed to detect the relatively small shock wave produced when the firing pin strikes the cartridge, but also has the durability needed to withstand the much larger shock wave produced by the ensuing combustion within the cartridge.
The output signal from the accelerometer 41 has a frequency spectrum for the small shock wave that is significantly different from the frequency spectrum for the ensuing large shock wave. Consequently, the processing section 21 can distinguish a shock wave that represents the firing pin striking a cartridge from a shock wave that represents some other type of event, such as combustion within a cartridge. For example, in order to identify the small shock wave, the processing section 21 could apply a fast Fourier transform (FFT) to the output of the accelerometer 41 , filter out frequency components that are outside a frequency band of approximately 5 KHz to 10 KHz, and then look for a pulse in the energy between 5 KHz and 10 KHz.
The sight 10 includes a gyroscope 43 , with an output that is coupled to the processing section 21 . The gyroscope is referred to herein as a rate gyro. In the disclosed embodiment, the rate gyro 43 is implemented with a MEMS device that is available commercially as part number ADXRS150 from Analog Devices, Inc. Although the disclosed embodiment uses the Analog Devices ADXRS150 device, it would alternatively be possible to implement the rate gyro 43 with any other suitable device.
The rate gyro 43 is capable of detecting angular movement of the sight 10 about a not-illustrated vertical axis that is spaced from the rate gyro 43 . Thus, the rate gyro 43 is a highly sensitive device that is effectively capable of detecting movement of the sight 10 in directions transverse to a not-illustrated center line of the objective lens section 16 .
The sight 10 includes a removable memory card 46 that, when present within the sight 10 , is operatively coupled to the processing section 21 . In the disclosed embodiment, the memory card 46 is a memory card of the type commonly used in digital cameras. However, it would alternatively be possible to use any other suitable device for the removable memory card 46 .
The sight 10 includes a battery 51 that, in the disclosed embodiment, is a replaceable battery of a known type. However, the battery 51 could alternatively be a rechargeable battery. The sight 10 also includes an external power connector 52 that can be coupled to an external source of power, such as a converter that converts alternating current (AC) to direct current (DC).
As mentioned above in association with FIG. 1 , the sight 10 has a switch panel 13 with a plurality of manually operable switches. These switches include a power switch 57 , and also include several other switches 58 – 65 that are each coupled to the processing section 21 , and that are discussed in more detail below. The battery 51 and the external power connector 52 are each coupled to inputs of the power switch 57 . When the power switch 57 is respectively actuated and deactuated, it respectively permits and interrupts a flow of current from the battery 51 and/or the connector 52 to circuitry 71 that is disposed within the sight 10 , and that requires electrical power in order to operate. The circuitry 71 includes the image detector 18 , the processing section 21 , the display drivers 30 and 31 , the external display 14 , the internal display 32 , the accelerometer 41 , the rate gyro 43 , and the memory card 46 .
The sight 10 has a connector 81 that is coupled to the processing section 21 . The connector 81 can be used to upload image data or video data from the sight 10 to a not-illustrated computer, as discussed later. In addition, the connector 81 can be used to download an electronic reticle from a computer to the sight 10 , as also discussed later. In the disclosed embodiment, the physical configuration of the connector 81 , as well the protocol for transferring information through it, conform to an industry standard that is commonly known as the Universal Serial Bus (USB) standard. However, it would alternatively be possible to use any other suitable type of connector and communication protocol, such as a standard serial connector and communication protocol, or a standard parallel connector and communication protocol.
The sight 10 includes a further connector 82 , through which video information can be transferred from the sight 10 to an external device, in a manner conforming to an industry video standard that is commonly known as the National Television Standards Committee/Phase Alternating Line (NTSC/PAL) standard. In the disclosed embodiment, the connector 82 is a standard component of the type commonly known as an RCA jack. However, it could alternatively be any other suitable type of connector, and information could be transferred through it according to any other suitable protocol.
FIG. 3 is a diagrammatic view of the internal display 32 , as seen by the eye 37 of a person looking into the sight 10 through the eyepiece optics 36 . In a normal operational mode, the display 32 presents a view of the scene 17 , as captured by the image detector 18 through the objective lens section 16 . The scene 17 is shown diagrammatically in FIG. 2 by broken lines.
The processing section 21 superimposes a reticle 101 – 105 on the image of the scene 17 . In the disclosed embodiment, the reticle includes a small center circle 101 , and four lines 102 – 105 that each extend radially with respect to the circle 101 , and that are offset by intervals of 90°. The reticle 101 – 105 is a digital image that is downloaded into the sight 10 through the USB connector 81 , and that is stored by the processing section 21 in a non-volatile portion of the memory 23 . The reticle can have almost any configuration desired by a user. In particular, a reticle with virtually any desired configuration can be created by a user in a separate computer, or obtained by the user from the sight manufacturer or a third party through a network such as the Internet. The new reticle can then be downloaded electronically in digital form through the connector 81 , and is stored in the memory 23 of the processing section 21 .
The processing section 21 takes the reticle that is currently stored in the memory 23 , and digitally superimposes the reticle on images that will be sent to the display 32 . In FIG. 3 , the reticle 101 – 105 has been superimposed on the image in a manner so that the reticle is centered on the display 32 . However, the position where the reticle appears on the display 32 , and thus the position of the reticle relative to the image of the scene 17 , can be adjusted in a manner that is described later.
The processing section 21 can also superimpose some additional information on the image of the scene 17 . In this regard, the lower left corner of the display 32 includes a windage or azimuth adjustment value 111 . As mentioned earlier, the position of the reticle 101 – 105 on the display 32 can be adjusted, in a manner that is discussed in more detail later. The windage adjustment value 111 is a positive or negative number that indicates the offset by which the reticle 101 – 105 has been adjusted either leftwardly or rightwardly from the centered position shown in FIG. 3 .
The upper right corner of the display 32 has a battery charge indicator 113 that is divided into three segments, and that is used to indicate the state of the battery 51 . In particular, when the battery is fully charged, all three segments of the battery charge indicator 113 are displayed. Then, as the battery 51 becomes progressively discharged, there will be a progressive decrease in the number of displayed segments of the battery charge indicator 113 .
The upper left corner of the display 14 presents an image count value 114 , and this count value 114 relates to the fact that the processing section 21 can store images in the removable memory card 46 , as discussed later. The image count value 114 is an indication of how many additional images can be stored in the unused space that remains within the memory card 46 .
The top center portion of the display 32 has a capture mode indicator 115 , and a firing pin detection indicator 116 . The capture mode indicator 115 shows which of two capture modes is currently in effect, as discussed later. The firing pin detection indicator 116 indicates whether or not the sight is currently enabled to detect the firing pin striking a cartridge, as discussed later.
The bottom central portion of the display 32 includes an autoboresight alignment indicator 117 , for a purpose that is not related to the present invention, and that is therefore not described here in detail. An angular error indicator 120 appears in the central portion of the display 32 . The indicator 120 is a circle that is larger than and concentric to the circle 101 at the center of the reticle 101 – 105 . The diameter of the indicator 120 is increased and decreased in response to variation of a particular operational criteria, as discussed later. Depending on the current mode of operation of the sight 10 , the reticle 101 – 105 and the various indicators 111 – 120 may all be visible, or only some may be visible.
FIG. 4 is a diagrammatic view of the switch panel 13 , and shows each of the manually operable switches 57 – 65 of the switch panel 13 . The types of switches and their arrangement on the panel 13 is exemplary, and it would alternatively be possible to use other types of switches, and/or to arrange the switches in a different configuration. The power switch 57 has already been discussed above, and therefore is not discussed again here.
The switch 58 is a detect switch. As mentioned earlier, the accelerometer 41 ( FIG. 2 ) is capable of detecting a shock wave that occurs when the firing pin of the firearm strikes a cartridge. Successive manual actuations of the detect switch 58 alternately instruct the processing section 21 to enable and disable this detection feature. When this feature is respectively enabled and disabled, the detection indicator 116 is respectively visible on and omitted from the display 32 .
The switch 59 is a mode switch. In one operational mode, the processing section 21 of the sight 10 can take a single image generated by the image detector 18 , and store this image in the removable memory card 46 . In a different operational mode, the processing section 21 can take several successive images generated by the image detector 18 , which collectively form a video clip, and store these images in the memory card 46 . Successive actuations of the mode switch 59 cause the processing section 21 to toggle between these two operational modes. When the mode for storing video clips is respectively enabled and disabled, the detection indicator 115 is respectively visible on and omitted from the display 32 . There are two types of events that will cause the processing section 21 to save an image or a video clip.
First, if the detect switch 58 has been used to enable detection of the firing pin striking a cartridge, the processing section 21 will respond to each detection of this event by saving either a single image or a video clip in the memory card 46 , depending on whether the capture mode that has been selected using the mode switch 59 is the image capture mode or the video capture mode. It will be recognized that, since a video clip is a series of several images, saving a video clip in the memory card 46 will take up several times the storage space that would be required to save a single image. After saving an image or a video clip, the processing section 21 adjusts the image count indicator 114 presented on the display 32 . In particular, if a single image is stored, then the count value 114 will simply be decremented. On the other hand, if a video clip is saved, the value of the indicator 114 will be reduced by an amount that corresponds to the number of images in the video clip.
The other event that will cause the processing section 21 to save one image or a video clip is manual operation of the switch 64 , which is a capture switch. Whether the processing section 21 saves a single image or a video clip is dependent on the capture mode that has been selected using the mode switch 59 . When the capture switch 64 is manually operated, the processing section 21 selects either a single image or a video clip from the current output of the image detector 18 , and then saves this image or video clip in the memory card 46 . As mentioned earlier, a separate and not-illustrated computer can be coupled to the connector 81 , and the processing section 21 can upload to that computer the images or video clips that are stored in the memory card 46 .
The switch 63 is a rocker switch that serves as a zoom control switch. Pressing one end of the switch 63 increases the zoom factor, and pressing the other end decreases the zoom factor. In the disclosed embodiment, the zoom is continuous and can range from 1× to 4×. When the disclosed system is operating at a zoom factor of 4×, a center portion is extracted from each image produced by the image detector 18 , where the center portion has a size of 320 by 240 pixels. This center portion is then displayed on the color display 32 , with each pixel from the center portion being mapped directly on a one-to-one basis to a respective pixel of the display 32 .
When the zoom factor is at 1×, the reformatter 26 essentially takes an entire image from the image detector 18 , divides the pixels of that image into mutually exclusive groups that each have 16 pixels arranged in a 4 by 4 format, averages or interpolates the 16 pixels of each group into a single calculated pixel, and then maps each of the calculated pixels to a respective corresponding pixel of the display 32 . Similarly, when the zoom factor is at 3×, the reformatter 26 essentially takes an image from the image detector 18 , extracts a center portion having a size of about 960 pixels by 720 pixels, divides the pixels of this center portion into mutually exclusive groups that each have 9 pixels arranged in a 3 by 3 format, averages or interpolates the 9 pixels of each group into a single calculated pixel, and then maps each of the calculated pixels to a respective corresponding pixel of the display 32 . As still another example, when the zoom factor is at 2×, the reformatter 26 essentially takes an image from the image detector 18 , extracts a center portion having a size of about 640 pixels by 480 pixels, divides the pixels of this center portion into mutually exclusive groups that each have 4 pixels arranged in a 2 by 2 format, averages or interpolates the 4 pixels of each group into a single calculated pixel, and then maps each of the calculated pixels to a respective corresponding pixel of the display 32 .
As mentioned above, the zoom from 1× to 4× is continuous in the disclosed embodiment. When the zoom factor is between 1× and 2×, between 2× and 3×, or between 3× and 4×, the reformatter 26 takes an appropriate portion of an image, and then groups, interpolates and maps the pixels of this portion into the pixels of the display 32 , in a manner analogous to that discussed above. Although the zoom in the disclosed embodiment is continuous, it would alternatively be possible for the zoom factor to be moved between discrete zoom levels, such as the four discrete zoom levels of 1×, 2×, 3× and 4×. In addition, although the zoom range in the disclosed embodiment is 1× to 4×, it would alternatively be possible to use some other zoom range.
With reference to FIG. 4 , the switch 65 is a four-way reticle switch. Any one of the upper, lower, left or right sides of this switch (as viewed in FIG. 4 ) can be manually operated in order to respectively indicate a selection of up, down, left or right. Each time the upper side of the switch 65 is actuated, the position of the reticle 101 – 105 is adjusted upwardly with respect to the display 32 , and thus with respect to the image of the scene 17 that is presented on the display 32 . Each such actuation of the switch 65 causes the reticle 101 – 105 to be moved upwardly by a predetermined number of pixels, and the elevation value 112 in the lower right corner of the display 32 is incremented in response to each such adjustment. Similarly, if the lower side of the switch 65 is actuated, the reticle 101 – 105 is adjusted downwardly on the display 32 by the predetermined number of pixels, and the elevation value 112 is decremented. Similarly, actuation of the left or right side of the switch 65 causes the reticle 101 – 105 to be adjusted leftwardly or rightwardly by a predetermined number of pixels on the display 32 , and causes the windage value 111 in the lower left corner of the display 32 to be either incremented or decremented.
As mentioned above, the sight 10 is capable of capturing and storing either single images or short video clips. In order to view these stored images or clips, the user presses the view switch 62 , thereby causing the processing section 21 to use the external display 14 to present either the first still image from the memory card 46 , or the first video clip from the memory card 46 . FIG. 5 is a diagrammatic view of the display 14 with a recorded image displayed thereon. It will be noted that the recorded image includes not only the scene, but also the reticle 101 – 105 , so that the user can see where the reticle was positioned with respect to the scene when the trigger of the rifle was pulled.
If the memory card 46 contains more than one image or video clip, then an arrow 142 will be visible to indicate that the user can move forward through the images or video clips. The user presses the right side of the reticle switch 65 in order to move to the next successive image or video clip. Except when the user is viewing the first image or video clip, an arrow 141 will be visible to indicate that the user can move backward through the images or video clips. The user presses the left side of the reticle switch 65 in order to move backward through the images or video clips. The view indicator 142 will be visible except when the user is viewing the last image or video clip, and the view indicator 141 will be visible except when the user is viewing the first image or video clip. The view mode is terminated by pressing the switch 62 a second time, in order to turn off the external display 14 and thereby conserve battery power.
As is well known to persons who use rifles and similar weapons, care must always be used to avoid pointing the rifle at anyone or anything that the user does not intend to shoot, in case there is an accidental discharge of the rifle. The sight 10 is designed to reduce the likelihood that the rifle may be inadvertently pointed in a direction that presents a safety hazard. In particular, the sight 10 includes the external display 14 , in order to avoid displaying any recorded images from the memory on the internal display 32 . This avoids a situation in which a hunter might mistake a recorded image on the internal display 32 for an actual view of the target, and then discharge the firearm in the belief that he or she was shooting at something in the recorded image, when in fact the rifle was actually aimed at something or someone else.
A further consideration is that, even with the presence of the external display 14 , there could still be a potential safety hazard if a user became distracted while viewing recorded images on the display 14 , and inadvertently pointed the rifle in a direction that presented a safety hazard. A similar scenario is that the user might inadvertently point the rifle in an unsafe direction while trying to orient the sight 10 so that another person can see the images on the display 14 . Or the user might hand the rifle with the sight 10 to that other person, in order to allow the person to have a good view of images presented on the external display 14 . That other person might then point the rifle in an unsafe manner, either because the person was distracted by the displayed images, and/or because the person simply was not suitably familiar with the basic principles of safe weapon handling.
The sight 10 is designed to also avoid this latter type of hazard. More specifically, as mentioned above, the accelerometer 41 is very sensitive and can detect the force of gravity. Consequently, as the sight 10 is progressively moved from a position where the rifle barrel is horizontal to a position where the rifle barrel is pointing vertically upwardly, the output signal of the accelerometer 41 will have a force component due to gravity that progressively increases. Based on that force component, the processor 22 of the sight 10 does not present any images on the external display 14 , unless an optical centerline of the sight 10 (which extends generally parallel to the barrel of the attached rifle) is within 10° to 20° of a vertical reference. Consequently, the rifle barrel will be pointing almost directly upwardly wherever the external display 14 is actuated and showing any recorded image information.
Although the sight 10 uses the accelerometer 41 to determine its orientation, it would alternatively be possible to use any other suitable sensor arrangement to detect orientation. As one example, it would be possible to use a group of conventional mercury switches having different orientations.
The switch 61 serves as an angle rate switch that can be operated to enable and disable the display of an angular error rate, as sensed by the rate gyro 43 . In particular, successive manual actuations of the switch 61 will alternately enable and disable this function. When this function is respectively enabled and disabled, the angular error indicator 120 is respectively visible on and omitted from the display 32 . When this function is enabled, the processing section 21 monitors the output of the rate gyro 43 . Typically, a user will be aiming the firearm and attempting to keep the reticle center 101 accurately centered on a portion of the scene 17 that is considered to be a target.
If the user happens to be holding the firearm very steady, then the rate gyro 43 will detect little or no angular motion of the sight 10 and the firearm, or in other words little or no transverse movement thereof. Consequently, the processing section 21 will present the indicator 120 as a circle of relatively small diameter, in order to indicate to the user that the firearm is being relatively accurately held on the selected target. On the other hand, if the user is having difficulty holding the firearm steady, then the rate gyro 43 will detect the greater degree of angular movement of the firearm and the sight 10 . Consequently, the processing section 21 will display the indicator 120 with a larger diameter, thereby indicating that the reticle center 101 is not being held on the target as accurately as would be desirable.
In the disclosed embodiment, the change in the diameter of the indicator 120 is continuous. In other words, a progressive increase in the amount of angular movement of the firearm and the sight 10 results in a progressive increase in the diameter of the indicator 120 . Conversely, a progressive decrease in the amount of angular movement of the firearm and sight results in a progressive decrease in the diameter of the indicator 120 . The user will therefore endeavor to squeeze the trigger of the firearm at a point in time when the reticle center 101 is centered on the target, and when the indicator 120 has a relatively small diameter that indicates the firearm is currently being held very steady.
The remaining switch 60 on the switch panel 55 is a boresight switch, and is used to enable and disable an autoboresight alignment mode. When this mode is respectively enabled and disabled, the autoboresight alignment indicator 117 is respectively visible on and omitted from the dismay 32 . As indicated earlier, the autoboresight alignment function is not related to the present invention, and therefore is not described here in detail.
Hunting regulations in most states stipulate that hunting is allowed during the time from one-half hour before sunrise to one-half hour after sunset. The intent of these regulations is to prevent the unsafe practice of shooting in very low light levels, where the actual identity of a target may be questionable. The level of illumination at one-half hour before sunrise and at one-half hour after sunset is sometimes referred to as “civil twilight”, and falls in a luminance range of 0.1 to 1.0 foot-candles. This luminance range corresponds to a cloudless sky. Other conditions can reduce ambient illumination to a level below that of civil twilight at almost any time during the day, for example where there is a dense cloud cover, or where a hunter is in a dense forest. There is no easy way for hunters and game wardens to determine actual levels of illumination, and this is why states have adopted the compromise approach of defining allowable hunting conditions in terms of dusk and dawn, rather than in terms of actual levels of illumination.
The image detector 18 , based on its sensitivity and integration time, can give a direct measure of the actual levels of illumination present in scenes viewed through the sight 10 . Consequently, the processing section 21 analyzes the images received from the image detector 18 , in order to determine the ambient level of illumination within the detected scene. In the disclosed embodiment, the processing section 21 averages the brightness of all of the pixels in a given image, and then compares the calculated average to a predetermined threshold that corresponds to civil twilight. Alternatively, however, any other suitable technique may be used to make this analysis. If the processing section 21 determines that the calculated average brightness is above the predetermined threshold, indicating that the level of ambient illumination is greater than civil twilight, then the sight 10 is operated in a normal manner. On the other hand, if the processing section 21 determines that the calculated average brightness is below the threshold, then the processing section displays a warning.
More specifically, FIG. 6 is a diagrammatic view of the internal display 32 while the sight 10 is being used to view a scene having a low level of ambient illumination. After calculating the average level of brightness for the displayed image, and determining that the calculated average is below the predetermined threshold, the processing section 21 displays the image with the addition of a warning 201 . In the disclosed embodiment, the warning 201 is the alphanumeric phrase “LOW LIGHT LEVEL”. In order to attract the attention of the user, this warning can be displayed in a color such as red, and/or can be made to blink. This warning notifies the user that light levels are low, thereby reminding the user that target recognition may be questionable and that hunting conditions may be unsafe. A responsible hunter will not want to shoot in these conditions.
Although the warning 201 in the disclosed embodiment is the alphanumeric phrase “LOW LIGHT LEVEL”, it could alternatively be some other alphanumeric phrase, a symbol such as a circle with a slash through it, or a combination of a symbol and an alphanumeric phrase. In addition, as discussed above, the disclosed embodiment responds to detected low light levels by displaying the warning 201 in association with the detected image. Alternatively, however, it would be possible for the processing section 21 to respond to the detection of a low light level by inhibiting the display of any image of any scene. In that case, the processing section could display the warning 201 (without any image), or could simply disable the presentation of any information on the display 32 .
Virtually all states have a hunting regulation that requires hunters to wear a fluorescent orange garment above the waist while hunting. This color does not naturally occur in any big game animals or their environment, and is intended to be a visual cue to a hunter that a person is present, rather than a potential animal target. Even where such a garment is present, the patch of orange color may be partly obscured by other objects in the scene, or may be very small if the hunter is a significant distance from the person wearing the garment. In either case, the presence of the orange color in the scene may be inadvertently and unintentionally overlooked by a hunter, resulting in a potentially dangerous situation for the person wearing the garment.
As a safety measure, the control or processing section of the sight 10 monitors images received from the image detector 18 for any pixels therein that represent a fluorescent orange color in the scene. If this color is detected, then the processing section 21 superimposes a warning on the image. In this regard, FIG. 7 is a diagrammatic view of the internal display 32 while the sight 10 is being used to view a scene that includes a person wearing a fluorescent orange garment. In response to detection of the fluorescent orange color, the processing section 21 superimposes a warning 221 over the portion of the image where the fluorescent orange color was detected. In the disclosed embodiment, the warning 221 is a circle with a slash. In order to attract the attention of the user to the warning 221 , the warning can be presented in a color such as red, and/or can be made to blink.
As discussed above, the warning 221 in the disclosed embodiment is a symbol in the form of a circle with a slash. Alternatively, however, the warning 221 could be some other symbol, an alphanumeric phrase, or a combination of a symbol and an alphanumeric phrase.
Although one embodiment has been illustrated and described in detail, it will be understood that various substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the following claims.
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A weapon sight can be mounted on a weapon. According to still another aspect of the invention, the sight takes a selected action if it detects the presence of a selected color within radiation originating externally of the sight.
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[0001] This invention is concerned with a bonding tool and method for bonding together layers of a transducer device, employed in micro-electro-mechanical systems (MEMS) systems.
[0002] MEMS devices refer to mechanical and electrical components on the micrometer size. They are typically manufactured using planar processing similar to semiconductor processes. MEMS devices commonly range in size from the order of a micrometer (a millionth of a meter) to the order of a millimeter (thousandth of a metre).
[0003] The present invention is concerned with transducers that operate as actuators, where a mechanical movement is created in response to an electromagnetic or other force. The invention is also concerned with transducers that operate as generators where electromagnetic energy is created in response to mechanical movement.
[0004] The present invention has application to transducers which may be used as valves to control the flow of gasses and liquids. An example of the application for such a device is the manipulation of airflow about an aircraft wing to promote or delay flow separation to control, for example, vortex bursting thereon. In our co-pending UK patent application no. GB 0420293.3 filed on 10 Sep. 2004 and in our co-pending International (PCT) patent application no. GB05/050147 filed on 8 Sep. 2005 and published as WO2006/027630, there is disclosed a methodology for emitting controlled pulsed jets of air from outlets at or adjacent a leading edge of an aircraft wing.
[0005] In our co-pending UK patent application no. GB 0505628.8 filed on 18 Mar. 2005 and in our co-pending International (PCT) patent application no. EP06/060824 filed on 17 Mar. 2006, there is disclosed a method of making a bimorph actuator which comprises assembling and bonding flat outer layers of piezoelectric material such as piezoceramic lead zirconate titanate (PZT) to a flat intermediate reinforcement layer such as Titanium (Ti) while the inner layer is in an expanded condition relative to the outer layers. When all the layers are cooled, a lateral compressive stress develops in the outer layers of piezoelectric material.
[0006] The titanium intermediate reinforcing layer or shim may be as wide as 50-100 mm diameter, and of the order of 10-20 microns thick. Although the above method produces good results, it has been found that the method of bonding to PZT layers may under certain circumstances create deformation of the titanium shim, in particular ripples may be formed across its surface from thermally induced stress. This may weaken the bond with the PZT layers.
[0007] Improvements are desirable in the bonding process to avoid the possibility of such deformations, and to provide a strong and long-lasting bond.
SUMMARY OF THE INVENTION
[0008] The present invention provides in a first aspect a method of bonding together layers of a MEMS transducer device, including a first layer of a piezoelectric material, and a second layer of a metallic material having a thermal coefficient of expansion different from that of the first material, the method comprising the steps of:
[0009] positioning said first layer spaced from the second layer;
[0010] heating said layers to a bonding temperature;
[0011] bringing said layers together under pressure to effect a bond between adjacent surfaces of the layers; and
[0012] permitting said layers to cool to an operating temperature in which the first layer is under compressive strain and the second layer is under tensile strain.
[0013] The present invention provides in a second aspect a bonding tool for bonding together layers of a MEMS transducer device, the device including a first layer of a piezoelectric material, and a second layer of a metallic material having a thermal coefficient of expansion different from that of the first material, and the bonding tool comprising:
[0014] positioning means for selectively positioning said layers in a first configuration with said first layer spaced from the second layer, and in a second configuration with said layers in contact for bonding;
[0015] means for heating said layers to a bonding temperature in said first configuration; and
[0016] press means for pressing said layers together in said second configuration to effect a bond between adjacent surfaces of the layers.
[0017] In accordance with the invention, deformations in the layers arising from thermally induced stress are avoided, since the layers are heated to a bonding temperature while spaced apart and free to expand. When the layers are ready to be bonded together, they are moved to said second configuration in which the layers are in contact, and a bonding process takes place. Subsequently, said layers are cooled to an operating temperature in which one layer is under compressive strain and the other layer is under tensile strain.
[0018] An adhesive bonding layer may be applied as a coating to one or both of the contacting surfaces of the first and second layers. The bonding adhesive may be a material comprising benzocyclobutene, which may be spun onto the surfaces of the piezoelectric layers to a thickness of the order of 1.5 to 2.0 μm. It is preferred to raise the temperature of the layers to about 180° C., and to keep it at that temperature while the bonding operation takes place.
[0019] Alternatively, other means of bonding may be employed (eg. Eutectic, direct fusion, thermocompression).
[0020] Whilst the invention may have general application to any type of MEMS transducer, it is particularly applicable to unimorph or bimorph piezoelectric structures having a layer of piezoelectric material, comprising one of said layers, bonded to a metallic shim reinforcing layer of steel, copper, or as particularly preferred titanium, comprising the other of said layers. A unimorph structure may have a single layer of piezoelectric material bonded to a single reinforcing shim.
[0021] In the case of a bimorph structure, there may be a third layer positioned such that the first layer is sandwiched between the second and third layers. The third and second layers may be formed of a piezoelectric material, whereas said first layer may be formed as a reinforcing metallic shim. In the method of the invention, said third layer is positioned spaced from the first layer during the initial heating phase.
[0022] The positioning means may include a plurality of support and spacing members that engage at least the first layer (and the third layer where provided) at positions around the periphery of the layer. The support members are movable between extended and retracted positions, and in the extended position serve to hold the layers apart in said first configuration. In the retracted position, the support members disengage from the first layer (and third layer), permitting the layers to move together under gravity. In an alternative arrangement, a means is provided to positively move the layers together.
[0023] Each support member may comprise upper and lower fingers that engage said third and first layers respectively to hold the layers spaced apart. However this may create problems in that the fingers need to be relatively thin in order not to disturb excessively a layer of adhesive that may be disposed on one or more surfaces of the layers, and that the fingers may therefore be bent or deformed under repeated use. In a preferred form therefore each support member comprises a single relatively rigid bar with a thinner slotted formation at its free end to engage the first layer. The slotted formation may be internal of the rigid bar or external, projecting a short distance from the free end of the rigid bar. As regards the third layer, whilst it would be possible in some arrangements for a further slotted formation to engage the third layer, or possibly for the third layer just to engage the top of the rigid bar, it is preferred to provide a support band around the periphery of the third layer to engage the top of the rigid bar, for example an elastomeric O ring, such as a quad ring. When the rigid bar is retracted, the band disengages from the top of the rigid bar, and the third layer falls under gravity on top of the first layer.
[0024] A further issue in assuring a smooth uniform contact between the first and second layers is the surface roughness of the layers, which may be significant, and that one or other of the layers may be deformed to an extent out of a flat planar condition. Whilst a certain amount of roughness may be desirable to improve bonding, excessive roughness may harm the bond. More importantly, deformation out of plane may harm the bond.
[0025] In accordance with the invention, there is provided a press means for pressing said layers together in said second configuration to effect a bond between adjacent surfaces of the layers, wherein said press means includes a compliant caul member positioned over a press head for contacting said layers during the pressing operation for evenly distributing the press force across the surface of the layers. It has been found that such a caul, consisting for example of a thin layer of fluorelastomer, may significantly improve the quality of the bond over the surface of the layers.
[0026] In a third aspect, the invention provides a bonding tool for bonding together layers of a MEMS transducer device, the device including a first layer of a piezoelectric material, and a second layer of a metallic material having a thermal coefficient of expansion different from that of the first material, and the bonding tool comprising:
[0027] positioning means for positioning said layers in a configuration with said layers in contact for adhesive bonding;
[0028] means for heating said layers to an adhesive bonding temperature in said first configuration; and
[0029] press means for pressing said layers together in said second configuration to effect a bond between adjacent surfaces of the layers, wherein said press means includes a compliant caul positioned over a press head for contacting said layers during the pressing operation for evenly distributing the press force across the surface of the layers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Preferred embodiments of the invention will now be described with reference to the accompanying drawings, wherein:—
[0031] FIG. 1 is a plan view of a 50 mm diameter stainless steel shim showing rippling distortion due to thermally induced stress;
[0032] FIG. 2 is a plan view of a 50 mm bonding jig in accordance with the invention with support members comprising long pairs of flags;
[0033] FIG. 3 is a cross sectional schematic showing operation of a first embodiment of pzt stack bonding tool, wherein FIG. 3 a shows layers of a MEMS device spaced apart during a heating phase, and FIG. 3 b shows a bonding phase wherein the bonding temperature has been reached, separator flags are withdrawn and the stack comes together;
[0034] FIG. 4 is a cross sectional schematic showing operation of a first embodiment of a pzt stack bonding tool, wherein FIG. 4 a shows layers of a MEMS device spaced apart during a heating phase, and FIG. 4 b shows a bonding phase wherein the bonding temperature has been reached, separator flags are withdrawn and the stack comes together;
[0035] FIG. 5 shows a MEMS device sample prepared using a prior art bond process: the shim is wrinkled and there are many voids present suggesting a poor quality bond; and
[0036] FIG. 6 shows a MEMS device sample prepared using the bond process of the invention: the shim is free of wrinkles and no voids are visible.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Referring to FIG. 1 , this shows a stainless steel shim that has been used in the process according to the above mentioned UK patent application no. GB 0505628.8 filed on 18 Mar. 2005, to make a 50 mm diameter PZT/shim/PZT stack forming a bimorph actuator. The shim is distorted due to its being rigidly clamped between the wafers and unable to expand. As the stack was heated the shim expanded to a greater degree than the PZT and not being free to move, the shim either buckled out of plane or underwent plastic deformation, which resulted in the distortion observed.
[0038] Referring to FIGS. 2 and 3 , a first embodiment of the invention includes a bonding jig 2 . This jig was designed to fit onto a standard 100 mm wafer bonding chuck 4 . Four locating pins 5 provide lateral restraint during assembly and flag retraction. A 52 mm diameter circular recess 6 in the jig provided lateral support for a PZT wafer stack 8 . Three pairs of supporting retractable flags 12 were provided to the standard separator retraction mechanisms to provide support for the stack. The flags were designed so that once the curing temperature was reached they could be retracted allowing the wafers to come together under gravity. At this point a load was applied to ensure good contact between the layers.
[0039] Referring to FIGS. 3 a and 3 b , the PZT wafer stack 8 comprises a first layer or shim 20 of titanium and second and third layers 22 , 24 are piezoelectric material. Retractable flags 12 comprise an upper finger 14 and a lower finger 16 . as shown in FIG. 3 a lower finger 16 serves to space first layer 20 from second layer 22 and upper finger 14 serves to space third layer 24 from first layer 20 . Faces of the respective layers are coated with a suitable adhesive material for example BCB. In the configuration shown in FIG. 3 a , the stack is heated to a bonding temperature of about 250° C. Subsequently, as shown in FIG. 3 b , the fingers 12 are withdrawn from the stack, permitting the layers to come together in contact under gravity. A press means (not shown) presses the layer together while the temperature is maintained at curing temperature until the layers are bonded together.
[0040] The following example of a bimorph actuator was produced.
Example
[0041] The actuator comprises a first intermediate reinforcing layer or shim of titanium, bonded to second and third outer layers of piezoelectric material. The piezoelectric material is a piezoceramic material comprising lead zirconate titanate. The intermediate layer may alternatively be stainless steel or copper alloy. Each outer layer of piezoelectric material has a surface flatness of about +/−1 μm and a total thickness of the order of about 20 to 100 μm. Values for the thermal mismatch induced residual stress in the shim 20 showed that titanium would be the most appropriate material for fabrication of the centre vane of the piezoelectric bimorph. A stack was prepared from two 50 mm×2 mm pz26 disks and a 50 mm diameter×12.7 μm section of titanium. The prepared faces of the pzt were first sputter coated with 100 nm nominal chrome films to form the centre electrode of the stack. The pzt disks were spin coated with bcb (benzocyclobutene—see below) and pre-cured to give dry films of approximately 2 μm thickness. The titanium was prepared by rinsing with acetone, isopropyl alcohol and deionised water. This was followed by drying with a nitrogen gun and dehydration at 200° C. for 30 mins. The titanium shims were prepared using a solvent wash followed by treatment with Ar and O 2 plasmas. The plasma treatment, whilst effective, was time consuming and tricky to perform so an alternative method was sought. Experimental trials showed that, in the case of titanium, chemical etching in a commercial titanium etchant (HNO 3 /HF) for 1 minute after solvent washing gave bonds that appeared to be as good as those obtained via the plasma treatment.
[0042] An adhesion promoter (dow chemical t1100) was spun on to both sides of the shim. The pzt disks and shim were then loaded into a bonding jig. After the bond chamber was evacuated the sample was heated to 230° C. After withdrawal of the separation flags a load of 875 n was applied and held for 8 hours to cure the adhesive.
[0043] BCB resin (Benzocyclobutene) (supplied by Dow Chemical under the trade name Cyclotene) is a spin coatable thermosetting adhesive. It is available is a range of viscosities and can give films between 900 nm and 8 μm thickness in a single application, in addition the polymerisation reaction forms no by-products. After spin coating the adhesive is soft baked at 75° C. for 5 minutes to evaporate the solvent carrier and results in a dry film that presents few handling problems. No significant curing occurs below 150° C. resulting in long shelf life for uncured films. Curing must be carried out in the absence of oxygen to avoid the formation of unwanted secondary phases or total oxidation of the adhesive. Curing may be performed in either a vacuum or an inert ambient. Typical cure times are 8 hours at 180° C. or 1 hour at 250° C. Once fully cured the resin is resistant to most chemical agents and has a maximum use temperature of around 350° C. according to manufacturer's data. We have determined that BCB would potentially have good gap filling properties on rough surfaces.
Second Embodiment
[0044] The second embodiment overcomes some issues with regard to the first embodiment. The central locating hole 6 in the tool was too large so the control over the lateral alignment of the disks was poor. The bonded PZT disks could be misaligned by as much as 2 mm, which led to difficulties later on during the grinding process. The overhanging, unsupported sections of the disks could easily become damaged. The second embodiment had a smaller centre hole, which gave much improved lateral alignment between the disks but reduced the tolerance to variations in disk diameter to +/−0.5 mm. The thin, flexible pairs of separation flags 12 of the first embodiment gave poor support in vertical plane. It was possible for the flags to be bent downwards and laterally by the large mass of the PZT disks and this could result in the shim being pinched between them. The shim could then become displaced horizontally when the flags were withdrawn. As previously discussed it is essential to maintain separation between the three components of the stack during the heating phase of the bond process in order to avoid wrinkling of the shim and to impart the required degree of residual stress. The first embodiment supported the wafers directly on the separation flags during the heating phase. It was noted that the flags frequently stuck to the adhesive on disk surfaces causing the process to abort and the run to be lost.
[0045] Referring now to FIGS. 4 a and 4 b , a second embodiment of the invention is shown, wherein similar parts to those of FIGS. 3 a and 3 b are denoted by the same reference numeral. A spacing and supporting means comprises three solid support bars 40 positioned around the periphery of the stack 8 and each having a slotted formation 42 projecting from its free end and providing a 100 μm deep horizontal slot which titanium shim 20 is fitted. Since the adhesive is formed on the faces of the piezoelectric layers, this ensured that no contact was made with either adhesive coated face. The third layer 24 has a surrounding quadring 44 (Type 4032 VITON fluoroelastomer. Quad rings are a type of O-ring with a four lobed square cross-sectional profile that prevents them from rolling off). As shown FIG. 4 a , the layers of the stack 8 are held in a spaced apart configuration while the stack is heated to a temperature of 180° C. When the bonding temperature is reached, the space bars 40 are withdrawn as shown in FIG. 4 b to permit the layer 20 , 22 , and 24 to come together under gravity. The temperature is maintained whilst a load is applied by a press head 46 . A compliant caul 48 is fitted over the press head so as to engage the upper surface of the stack 8 during the bonding process. It had been found that the layers 20 - 24 had lenticular profiles of the order 4-8 μm height over the 50 mm diameter. For these wafers to form a high quality bond of regular thickness some slight bending would be necessary. As the load was applied between two rigid flat metal plates there was a strong possibility that distortion of this kind could not be achieved resulting in poor closure of the bond line. A controlled compliance was added to the system by use of a fluoroelastomer (VITON) disk of 0.5 mm thickness introduced between bonder load piston and wafer stack. Deformation of this layer gave a more even load distribution on samples that were not perfectly flat and allowed the disks to distort slightly so that the bond line could be closed.
[0046] In order to avoid problems of monitoring the stack temperature, a process was derived where the bond chamber was purged with nitrogen at slightly above atmospheric pressure throughout the heating phase. This satisfied the need for an inert atmosphere to prevent oxidation of the BCB and at the same time provided significantly improved thermal coupling between the heater and the bond tool. When used in conjunction with a heater thermocouple this gave tool temperatures that were a close match with that of the heater and a good degree of control. Once the desired temperature was reached the nitrogen purge was shut off and the chamber evacuated. The separator flags were then withdrawn and the load applied as per normal.
[0047] It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention which is defined in the accompanying claims.
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A bonding tool and method A bonding tool and method for bonding together layers of a MEMS transducer device, including at least one layer of a piezoelectric material, and an intermediate reinforcing layer of titanium, or other metal, comprising: positioning the layers above one another and spaced apart by means of spacing members, heating said layers to a bonding temperature, and retracting the spacing members so as to bring the layers together under pressure to effect a bond between adjacent surfaces of the layers, wherein a press head is employed with a compliant caul for evenly distributing the press force; and permitting said layers to cool to an operating temperature in which said piezoelectric layer is under compressive strain and the titanium layer is under tensile strain.
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CROSS-REFERENCE TO RELATED APPLICATION
The present disclosure relates to subject matter contained in priority Korean Application No. 10-2011-0002432, filed on Jan. 10, 2011, which is herein expressly incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This specification relates to an operating method for a clothes treating apparatus, and particularly, to an operating method for a clothes treating apparatus, capable of drying clothes by supplying hot air into a rotating drum.
2. Background of the Invention
In general, a clothes treating apparatus having a drying function, such as a washing machine or a clothes dryer, dries clothes (laundry) by putting the clothes, which are completely washed and dehydrated (spin-dried), into a drum, supplying hot air into the drum, and evaporating moisture of the clothes.
For example, a clothes dryer includes a drum rotatably installed in a main body and receiving laundry therein, a driving motor to drive the drum, a blowing fan to blow air into the drum, and a heating unit to heat air introduced into the drum. The heating unit may use thermal energy generated using electric resistance or heat of combustion generated by burning gas.
Meanwhile, in the related art dryer, as aforementioned, while drying clothes with supplying hot air into the drum, a humidity sensor mounted in the dryer is used to measure a content of moisture within the clothes. When the measured content of moisture is less than a predetermined level, it is determined as completion of the drying, thereby terminating the drying process. Here, since the introduced clothes are rotated along an inner wall of the drum in an entangled state in response to rotation of the drum during the drying process, there may exist an area without contact with hot air, which causes different dried levels for the clothes. Hence, a drying time should extend for drying the entire clothes, which may cause an increase in energy consumption and some clothes may excessively be dried.
In addition, if the clothes are dried in a stacked state with other clothes, generated wrinkles may be fixed without becoming smooth, resulting in generating excessive wrinkles.
SUMMARY OF THE INVENTION
Therefore, to address the drawbacks of the related art, an aspect of the detailed description is to provide a clothes treating apparatus capable of reducing a drying time and minimizing damages on the clothes by allowing for uniform drying of the clothes introduced.
Another aspect of the detailed description is to provide a clothes treating apparatus capable of minimizing generation of wrinkles, which may be generated due to friction between clothes and a drum during rotation of the drum.
To achieve these and other advantages and in accordance with the purpose of this specification, as embodied and broadly described herein, there is provided a method for operating a clothes treating apparatus including a hot air supplying unit provided with a heater and a blowing device, and having a drying function of drying clothes by supplying hot air into a drum by use of the hot air supplying unit, the method including rotating the drum with the clothes introduced into the drum, and supplying hot air into the drum by using the heater and the blowing device while the drum is rotated, wherein an air flow rate supplied by the blowing device changes during the hot air supplying step.
In one aspect of the present disclosure, an air flow rate that hot air is supplied may change intermittently or at a preset period while performing drying with supplying the hot air, thereby making the clothes moved more actively within the drum. That is, air pressure applied onto the clothes may change in response to an increase or decrease of the air flow rate, which may allow the entangled or pressed clothes to be free. Therefore, the clothes introduced into the drum may be uniformly dried and generation of wrinkles may be minimized.
Here, the hot air is not inevitably supplied. A case where only the blowing device runs with the heater off according to a dried level may be considered. Especially, at the last part of the drying in which the clothes are dried to some degree, if air is merely blown in with the heater off to allow the clothes to be dried at a relatively low temperature, it may be advantageous in the aspect of preventing the generation of wrinkles.
Meanwhile, the air flow rate supplied by the blowing device may change within a range between a first air flow rate and a second air flow rate higher than the first air flow rate. That is, the blowing device may be controlled to supply the first air flow rate and the second air flow rate, thereby simplifying a configuration of a controller.
Here, the air flow rate may change only when a moisture content within the clothes is less than a predetermined level. That is, at the beginning of the drying with a relatively large content of moisture, the clothes may be less affected by air pressure even if the air flow rate changes. Hence, the air flow rate can be decreased in a state that the weight of the clothes has been reduced as being dried to some degree, thereby reducing energy consumption and maximizing an effect by the variable air flow rate.
The hot air supplying step, namely, drying step may include a first drying step of increasing an inner temperature of the drum, a second drying step of constantly maintaining the inner temperature of the drum after the first drying step, and a third drying step of re-increasing the inner temperature of the drum after the second drying step.
The first drying step may be started right after the drying is initiated. In this step, the clothes contain a large content of moisture. Accordingly, even if hot air is blown in by the heater, the inner temperature of the drum relatively slowly increases.
The second drying step may follow the first drying step, and correspond to a section in which temperature is almost uniformly maintained by virtue of balancing between a quantity of heat supplied by the hot air and a quantity of heat adsorbed by moisture evaporated from the clothes by the supplied heat.
The third drying step may be a step in which the supplied quantity of heat starts to exceed the adsorbed quantity of heat due to the decrease of the moisture content contained in the clothes. In this step, when the quantity of heat generated from the heater is constantly maintained, the inner temperature of the drum may increase as a time elapses.
Therefore, when the air flow rate changes in the first drying step, an effect to some degree may be obtained. However, the weight of the clothes in the first drying step is heavier than the other steps, so it may not cause a great change in the movement of the clothes by the air pressure. Consequently, the air flow rate can change in the second or third drying step.
The air volume changing step in the third drying step may include increasing the air flow rate up to a second air flow rate, maintaining the second air flow rate for a preset time, and decreasing the air flow rate down to a first air flow rate. That is, the third step may be a process in which the drying is carried out to some degree and thus the inner temperate of the drum increases. Hence, a large air flow rate may be supplied to lower the temperature of hot air and make the clothes moved more actively, thereby more effectively preventing the generation of wrinkles.
Here, the air volume increasing, maintaining and decreasing steps may be repeated at preset time intervals. The rotating speed of the drum may be reduced when the air flow rate increases, namely, the second air flow rate is supplied, and the rotating speed of the drum may be recovered to the original state when the first air flow rate is supplied. That is, when the rotating speed of the drum is reduced during the supply of the large air flow rate to reduce a centrifugal force, the clothes can be more easily separated from the inner wall of the drum, thereby making the clothes moved more actively.
Meanwhile, the hot air supplying step may include measuring temperature of hot air exhausted from the drum, and increasing the air flow rate when the measured temperature of the exhausted air exceeds a predetermined temperature. That is, by measuring the temperature of air exhausted form the drum, the inner temperature of the drum can indirectly be measured, which may prevent the inner temperature of the drum from being excessively increased.
This may be measured based on a content of moisture contained in the clothes other than the temperature of the exhausted air. That is, when a moisture content is measured by an electrode sensor or the like disposed within the drum, the changes in the inner temperature of the drum may be indirectly judged. That is, when the moisture content is less than 7 to 10%, more wrinkles may be generated on the clothes due to friction between the clothes and the drum. Hence, when the moisture content measured is within the corresponding section, the air flow rate may increase to lower the inner temperature and reduce the friction between the clothes and the drum, thereby preventing the generation of wrinkles.
In addition to these, when the heater is configured to be blocked from power supply upon the increase in the inner temperature of the drum, a frequency of blocking power supplied into the heater may be measured so as to indirectly judge the changes in the inner temperature of the drum. Hence, the hot air supplying step may further include measuring a frequency of blocking the power supplied to the heater, and increasing the air flow rate when the measured blocking frequency is less than a predetermined level.
Meanwhile, the hot air supplying step may include accelerating/decelerating the rotating speed of the drum in an alternating manner. When the rotating speed of the drum is alternately accelerated/decelerated, the clothes pressed onto the inner wall of the drum may be free from the inner wall of the drum due to a drastic change in the centrifugal force. The thusly-separated clothes may be dropped onto the bottom surface of the drum, but they may be dropped after floating in the air for a while due to hot air supplied. Hence, the clothes may avoid friction against the drum as long as a time of floating in the air, which may result in prevention of wrinkle generation due to friction and damages on the clothes.
Here, the drum may be controlled to be rotated at a first speed for a preset time and then rotated at a second speed faster than the first speed for a preset time. The accelerating/decelerating step may be carried out when the moisture content of the clothes is less than a predetermined level or the inner temperature of the drum is more than a predetermined temperature.
In order to increase the floating time of the clothes in the air and realize a variety of movements of the clothes, a large air flow rate may be supplied during the accelerating/decelerating step as compared to the other steps.
In accordance with the aspects of the present disclosure having the configuration, an air flow rate that hot air is supplied may change intermittently or at a preset period during the drying process so as to make the clothes moved more actively within the drum, and accordingly make the entangled or pressed clothes free, thereby minimizing the generation of wrinkles. In addition, the clothes introduced into the drum can be uniformly dried.
Also, the supplied air flow rate may change not in a consecutive manner but in a sequential manner so as to simplify a configuration of a controller.
In addition, the rotating speed of the drum can be controlled to be accelerated/decelerated in the alternating manner while supplying the hot air, such that the clothes pressed onto the inner wall of the drum can be separated from the inner wall of the drum. The thusly-separated clothes may float in the air for a while due to the hot air supplied, thereby reducing a friction time against the drum.
Further, there is provided a method for operating a clothes treating apparatus comprising: drying the clothes by rotating the drum with the clothes introduced therein and supplying air into the drum while the drum is rotated; changing air flow rate into the drum in a certain time during drying; stopping the rotating the drum and supplying air when the clothes are dried to a pre-determined degree.
Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood 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 the detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention.
In the drawings:
FIG. 1 is a perspective view schematically showing one exemplary embodiment of a clothes treating apparatus in accordance with this specification;
FIG. 2 is a sectional view schematically showing an inner structure in the exemplary embodiment of FIG. 1 ;
FIG. 3 is a perspective view schematically showing the inner structure of FIG. 1 ;
FIG. 4 is a flowchart showing a drying process in the exemplary embodiment of FIG. 1 ;
FIG. 5 is a graph showing changes in an inner temperature of a drum according to a time lapse during the drying process in the exemplary embodiment of FIG. 1 ;
FIG. 6 is a graph showing changes in rotation speeds of a blowing fan and a drum according to a time lapse in the exemplary embodiment of FIG. 1 ; and
FIG. 7 is a graph showing changes in the rotation speed of the drum in another drying process in the exemplary embodiment of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
Description will now be given in detail of a clothes treating apparatus according to the exemplary embodiment, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and description thereof will not be repeated.
FIG. 1 is a perspective view schematically showing one exemplary embodiment of a clothes treating apparatus in accordance with this specification. The exemplary embodiment illustrates a dryer but the present invention may not be limited to the dryer. The present invention may also be applicable to any type of clothes treating apparatus, which is configured such that hot air is supplied to dry clothes and the used hot air is exhausted out of a drum.
As shown in FIG. 1 , the dryer 100 may include a main body 102 defining an appearance of the apparatus. A front surface of the main body 102 may be shown having an introduction opening 104 through which clothes as targets to be dried are introduced into the main body 102 . The introduction opening 104 may be open or closed by a door 106 . A manipulation panel 108 having various manipulation buttons for manipulation of the dryer may be located above the introduction opening 104 .
FIGS. 2 and 3 are a sectional view and a perspective view schematically showing an inner structure of the dryer 100 . As shown in FIGS. 2 and 3 , a drum 120 may be rotatably disposed within the main body 102 to dry clothes or targets to be dried therein. The drum 120 may be rotatably supported by supporters at front and rear sides thereof. The drum 120 may be connected to a power transfer belt (not shown) and a driving motor located at a lower portion of the dryer so as to be rotatable by receiving a rotational force.
A lower portion of the drum 120 may be shown having a first suction duct 130 , and a second suction duct 140 installed at the rear of the first suction duct 130 in a longitudinal direction of the main body 102 . The first and second suction ducts 130 and 140 may suck thereinto air, which is introduced from the exterior and present within the main body 102 , and supply the sucked air into the drum 120 . Here, air is supplied into the drum 120 via an inlet port (not shown) formed through the second suction duct 140 . The inlet port may extend in a longitudinal direction based on a center of the drum 120 such that air can be introduced into the drum via an entire surface of the drum 120 .
Besides, an example that the inlet port is formed at an upper or lower portion may be regarded.
A heater 150 may be installed within the first suction duct 130 so as to heat up introduced external air at a low temperature into air hot enough to dry the clothes. Also, although not shown, a moisture detecting sensor for measuring a content of moisture within the clothes introduced into the drum 120 may further be provided. Any type of sensor may be used as the moisture detecting sensor. As one example, an electrode sensor, which uses a pair of electrodes to measure moisture based on changes in resistance in response to a content of moisture.
Here, the first and second suction ducts 130 and 140 have been illustrated as physically separated two structures, but the present disclosure may regard an example that the two ducts are integrally formed, without being limited to the two structures.
Here, the first suction duct 130 may allow external air to be introduced thereinto via a suction port (not shown) formed at the main body 102 . The introduced external air may be heat up into hot air by the heater 150 so as to flow into the drum 120 . The air flowed into the drum 120 may then dry the clothes and thereafter be introduced into a front duct 160 located below the front surface of the drum 120 .
The air introduced into the front duct 160 may contain foreign materials, such as lint or dust existing on surfaces of the clothes. Accordingly, a lint filter 162 for filtering off the foreign materials may be installed within the front duct 160 . Consequently, the foreign materials may be filtered off from the introduced air via the lint filter 162 .
An exhaust duct 180 may be connected to the front duct 160 . The first exhaust duct 180 may define a part of an exhaust channel for discharging hot air passed through the front duct 160 to the outside of the main body 102 . A blowing fan 170 may be installed within the first exhaust duct 180 . The blowing fan 170 may suck air within the drum 120 to forcibly blow out of the dryer.
The blowing fan 170 may be driven by a separate motor from the driving motor. Hence, the blowing fan 170 and the drum 120 may be independently rotatable. The driving motor for driving the drum 120 may include an inverter control circuit for control of a rotating direction and speed of the drum 120 . Here, the inverter control circuit may include a specific controller.
The rear end of the first exhaust duct 180 may be shown having a second exhaust duct 190 . An end portion of the second exhaust duct 190 may communicate with the outside of the main body 102 to act as an exhaust port. Hence, the first and second exhaust ducts 180 and 190 and the communicating portion may define an exhaust channel. Consequently, air introduced via the first suction duct 130 may flow sequentially via the second suction duct 140 , the drum 120 , the front duct 160 , the first exhaust duct 180 and the second exhaust duct 190 , thereby being discharged out of the main body 102 . Here, the second exhaust duct 190 may include a duct connected to the outside of a space in which the exemplary embodiment is installed so as to directly discharge exhaust gas to the outside. A heat exchanger may be installed in the second exhaust duct 190 so as to cool and condense exhaust gas, thereby discharging to the inside.
Hereinafter, description will be given of a drying process in accordance with the exemplary embodiment with reference to FIG. 4 . Once drying is started, power is supplied to the heater to activate the heater and simultaneously the blowing fan and the drum are rotated. Here, the blowing fan may be rotated at speed of about 1200 to 170 rpm, and the drum may be rotated at speed of about 50 to 55 rpm. Such numerical values may be randomly set by a person skilled in the art according to the configuration of a dryer or a quantity of clothes introduced.
Upon supplying hot air into the drum, moisture contained in the clothes is evaporated by the hot air such that the clothes cam be dried. FIG. 5 is a graph showing changes in an inner temperature of the drum according to a time lapse during the drying process. As shown in FIG. 5 , an inner temperature of the drum increases within a relatively low range due to a large quantity of moisture at the beginning of the drying process, but is constantly maintained at an approximately 200° C. in the middle of the drying for which the quantity of heat contained in the hot air and heat of evaporation generated due to moisture evaporation are balanced with each other. Afterwards, as a moisture content of the clothes is lowered, the quantity of heat contained in the hot air is relatively increased, which results in a gradual increase in the inner temperature of the drum.
Therefore, in accordance with the exemplary embodiment, the changes in the inner temperature of the drum are detected. When the inner temperature is constantly maintained over a predetermined time, it is determined that the drying process is in a middle part, thereby changing a rotating speed of the blowing fan. The process of changing the rotating speed may be carried out by repeating three times a process of accelerating the blowing fan from the speed of 1200 to 1700 rpm to a higher level, namely, a speed of 2000 to 2700 rpm and then decelerating the blowing fan back to the original speed. Here, if the three-time repetition of the acceleration and deceleration is performed as one set, totally two sets of the repetition are carried out with a preset time interval during the middle part of the drying process.
The acceleration and deceleration may allow for the change in the air flow rate supplied into the drum. This may change air pressure applied to the clothes, which allows the clothes, which are in an entangled state and pressed onto an inner wall of the drum, to be free from other clothes and the inner wall of the drum. Consequently, a contact area between the clothes and the hot air can increase to raise a drying speed and reduce wrinkles generated on the clothes.
Afterwards, when the inner temperature of the drum increases as a time elapses, it means the drying process is approaching to the last part. In this case, the rotating speed of the blowing fan increases. Here, this state is maintained for about 3 to 5 minutes, and then the speed is decelerated. This process is repeated totally three times. When the rotating speed of the blowing fan increases, the rotating speed of the drum is decelerated to 45 to 45 rpm. During the last part of the drying process, the clothes become light due to decrease of moisture. Hence, upon supplying a large air flow rate, the clothes may rotate more actively. Here, when the high rotating speed of the drum is maintained, the clothes are closely adhered onto the inner wall of the drum due to a centrifugal force, thereby increasing friction due to air pressure. Therefore, the rotating speed of the drum may be reduced to prevent the increase in the friction and also facilitate separating of the clothes from the inner wall of the drum.
Especially, when the rotating speed of the drum is reduced and the air flow rate increases at the last part of the drying process, the dropped clothes may be temporarily floated in the air by air pressure, which may derive advantageous conditions in aspects of friction decrease and wrinkle removal. In addition, the rotating speeds of the drum and the blowing fan are repeatedly accelerated and decelerated, so the clothes can move or rotate more actively within the drum.
When air of high volume is supplied during the last part of the drying process, a temperature of hot air supplied may be decreased due to the fixed quantity of heat from the heater. Accordingly, the drying is carried out at low temperature, which may allow generated winkles to become smooth other than being fixed, thereby minimizing generation of winkles. While repeating such process, a moisture content within the clothes is measured. When the measurement meets a drying completion condition, the drying process may be ended.
Especially, even if hot air of high temperature is supplied during the last part of the drying process, a quantity of heat, which is contained in the hot air but exhausted to the outside without being used, increases due to a less content of moisture within the clothes. Hence, it is important to control an air flow rate by rapidly checking whether the drying process is approaching to the last part. In general, a great temperature deviation according to a measuring position is exhibited due to the rotation of the clothes within the drum and an irregular air flow rate, so an accurate measurement is not easy to be performed.
Accordingly, an example may be considered in which the inner temperature of the drum is not directly measured but other parameters are measured to indirectly judge the inner temperature of the drum. One of those parameters may be a temperature of air exhausted from the drum. That is, when air within the drum is exhausted out of the drum via the exhaust duct, since an area of the exhaust duct is smaller than the drum, it may be possible to measure a relatively accurately temperature. Hence, if the temperature of the exhausted air is measured and the changes in the temperature are observed, it may be possible to check to which level the drying process has been done, namely, to which part the drying process corresponds among the beginning, middle, and last parts.
Another parameter may be a moisture content within the clothes. Besides, the heater may be configured to be blocked from power supply for prevention of overheat according to the inner temperature of the drum. The frequency of blocking the power supply may also be used as a parameter for indirectly judging the inner temperature of the drum.
In the meantime, for prevention of winkle generation, a time, for which the clothes bump against the inner wall of the drum at the last part of the drying process, in detail, at a time point when the moisture content is about 7 to 10%, may be made as short as possible. As described above, the clothes are lifted to the upper portion of the drum by a lifter installed at the inner wall of the drum in response to the rotation of the drum and thereafter dropped onto the bottom of the drum by the gravity. This process has been revealed as one of causes of generating winkles according to experimental results. Hence, in order to prevent this, it is necessary to minimize a time for which the clothes bump against the inner wall of the drum. An operating method therefor is shown in FIG. 7 .
FIG. 7 is a graph showing the changes in the rotating speed of the drum at the last part of the drying process, in detail, at the time point when the moisture content is about 7 to 10%. As shown in FIG. 7 , the drum is being accelerated and decelerated to 63 rpm and 50 rpm per 2 seconds. When the drum is accelerated from 50 rpm to 63 rpm, the clothes are closely adhered onto the inner wall of the drum due to an increase in a centrifugal force, which makes the clothes moved together with the drum so as to be lifted. Afterwards, when the drum is decelerated, the contact force between the clothes and the drum is reduced due to the decrease of the centrifugal force. Accordingly, some clothes are dropped down. However, the clothes may not be immediately dropped onto the bottom but floated in the air for a preset time, which may result in minimization of a collision time of the clothes against the inner wall of the drum.
In order to increase the floating time in the air, as aforementioned, the blowing fan may be rotated with a relatively large air flow rate, for example, at speed of 2000 to 2700 rpm, during the acceleration and deceleration section, as compared to the normal state.
The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.
As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.
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A method for operating a clothes treating apparatus comprising a hot air supplying unit provided with a heater and a blowing device, and having a drying function of drying clothes by supplying hot air into a drum by use of the hot air supplying unit, includes rotating the drum with the clothes introduced therein, and supplying hot air into the drum by using the heater and the blowing device while the drum is rotated, wherein an air flow rate supplied by the blowing device changes during the hot air supplying step.
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This invention was made with Government support under Contract Number NCC3-172 awarded by NASA. The Government has certain rights in the invention.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the use of dynamic light scattering (DLS) for the characterization of the structure and dynamics of such diverse systems as solids, liquid crystals, gels, solutions of biological macromolecules, electrolyte solutions, dispersions of microorganisms, solutions of viruses, membrane vesicles, protoplasm in algae and colloidal dispersions.
2. Brief Description of the Prior Art
Light scattering techniques for particle size characterization follow directly from the work of Mie in 1908 on the scattering of electromagnetic waves from dielectric spheres. The scattering depends upon particle size, wavelength, and refractive index. Techniques for particle sizing based on the angular dependence and polarization of the scattered light intensity have been routinely used to study shapes and sizes of large particles, in the Mie scattering regime. Single particle scattering systems are among some of these techniques utilizing the Mie regime. In the early 1950's it was recognized that the spectrum of the scattered light contains additional hydrodynamic properties of the scatterers, that is, translational and rotational diffusion constants. A time dependent correlation function formalism first developed by Van Hove in 1954 for neutron scattering was extended to light scattering by Komarov and Fisher in 1963. Following the invention of the laser, Pecora in 1964 showed that the frequency of the distribution of light scattered from macromolecular solutions would yield values of the macromolecular diffusion coefficient and, under certain conditions, might be used to study rotational motion and flexing of macromolecules. In 1964, Cummins, Knable and Yeh used an optical mixing technique to spectrally resolve the light scattered from dilute suspensions of polystyrene spheres. Since this pioneering work, applications have proliferated and optical mixing spectroscopy has become a major research field. Optical mixing spectroscopy is concerned with making measurements of the temporal properties of the scattered light in order to study the dynamics of the fluctuations in a fluid.
Measurement of the first order electric field autocorrelation involves elaborate optics and electronics. Direct detection (self-beating) of the scattered light leads to the second order intensity-intensity time correlation function, and homodyne or heterodyne detection leads directly to the first order electric field autocorrelation. In both cases, efficient optical mixing imposes a strict spatial coherence requirement on the optical detection system.
As discussed in U.S. Pat. No. 4,927,268, the process of obtaining particle size information by means of DLS requires relatively sophisticated optics and computer processing. However, this disclosure is not entirely correct in stating that DLS is useful for only small particles of the same size. DLS is routinely used to study highly polydisperse systems, and, also importantly, DLS provides considerably more information regarding the structure and dynamics of the system under investigation. Up until a few years ago, DLS was a specialized tool confined to a research laboratory environment with limited impact on industrial processing. However, simultaneous breakthroughs in the use of semiconductor lasers, miniaturization of the optics, avalanche photodiodes for photon counting, advances in digital electronics, and refinements in data inversion algorithms have opened up a vast area of industrial applications. DLS techniques have one other important advantage over single particle scattering systems as described by U.S. Pat. No. 4,927,268, and that is the large dynamic range over which they can operate. Single particle systems are limited to very dilute suspensions. DLS, however, can probe highly concentrated as well as very dilute systems. In particular, back scatter anemometers are even more effective in very concentrated systems. It is an object of the present invention to provide a generic multiple fiber optic probe which can be adapted to several diverse applications.
The existing state-of-art in fiber optic back scatter anemometers, which combine the transmitted and scattered laser light within the same fiber are those of Dyott [Microwave Opt. And Acoust., 2, 13 (1978)] and of Auweter and Horn [J. Colloid. and Interface Sci., 105, 399 (1985)]. Both types utilize a directional coupler to separate the transmitted and received signals propagating in the same sensor fiber. The transmitted beam emanates into the fluid at the full numerical aperture of the fiber, as defined in the fluid, and thus is not collimated. The back scattered signals are collected over an identical numerical aperture. In addition, the detection process is homodyne, that is, optical radiation reaching the detector comprises the sum of a local oscillator and the scattered signal. For efficient optical mixing, polarization of the two optical fields should be coincident and the wavefronts should be matched. The latter condition is easily satisfied since both optical signals travel in the same monomode fiber. The former condition is more severe and can degrade the optical mixing considerably.
One of the first uses of optical fibers in laser light scattering was described for in situ measurements of blood flow. Dyott [Microwave Optics and Acoust., 2, 13 (1978)] and Ross et al. [J. Colloid and Interface Sci., 64, 545 (1978)] presented a compact back scatter system for applications to particle sizing, motility, and flow measurements. This is believed to be the first portable light scattering apparatus which could be used in the field. It was also the first time that the incident laser beam and received signals were contained in a single unit. Somewhat different configurations have been described by Auweter and Horn [J. Colloid and Interface Sci., 105, 309 (1985)]. Dhadwal and Chu [App. Opt., 28, 411 (1989)] demonstrated the use of an optimized fiber optic receiver for both dynamic and static light scattering. In all the above cases a single fiber has been utilized in the composite probe. Dhadwal and Chu made a compact light scattering spectrometer using many single fiber/GRIN microlens probes.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an optical probe which is suitable for dynamic light scattering studies of diverse systems. The temporal properties of the scattered light can thereby be predicted from the first order electric field autocorrelation.
It is another object of the invention to avoid the use of a fiber directional coupler by assigning one or more optical fibers for transmitting an optical field to a scattering medium and using several optical fibers for receiving the scattered signal. The purpose of utilizing a plurality of optical fibers is to provide simultaneous filtering of the scattered light at different scattering angles. In accordance with another object of the invention, a quarter pitch gradient index (GRIN) microlens is used to transmit a collimated laser beam to the scattering region and to receive the scattered light.
In accordance with these and other objects of the invention, a system is provided which includes a probe body, a first optical fiber secured to the probe body, and a second optical fiber secured to the probe body. Means are provided for directing a laser beam into the first optical fiber. The first and second optical fibers each include a free end. The free ends of these fibers adjoin a quarter pitch, gradient index microlens. A laser source is provided for directing a laser beam into the first optical fiber. The beam passes through the microlens such that a collimated beam can be introduced into a scattering medium. Photodetecting means are connected to the second optical fiber. The second optical fiber may be positioned at the mirror image of the first optical fiber to provide homodyne detection. The second optical fiber may alternatively be positioned at a point which is not symmetrically located about the optical axis of the probe in order to provide self-beating detection.
A system requiring no gradient index microlens while providing efficient, self-beating detection is also provided. The system includes first and second optical fibers, means for causing a laser beam having a Gaussian distribution to emanate from a free end of the first optical fiber, detecting means connected to the second optical fiber, and a probe body to which the free ends of the first and second optical fibers are secured. The second optical fiber includes a free end positioned at a selected scattering angle so that it can function as a self-beating receiver. Additional optical fibers may be positioned relative to first optical fiber in order to define a range of scattering angles. However, using commercially available optical fibers, and taking into account the size of the probe, a back scatter probe with a scattering angle of about 157° was found to be optimum. Additional control of the waist and divergence, with use of additional optical components, of the Gaussian beam emanating from the free end of the fiber may permit a scattering angle close to 180°.
A method of detecting scattered light is also provided by the invention. The method includes the steps of providing a probe including a probe body, a first optical fiber secured to the probe body, a second optical fiber secured to the probe body, a quarter pitch, gradient index microlens having a front face and a back face, the first and second optical fibers including free ends adjoining the front face of the quarter pitch, gradient index microlens, inserting the probe into a scattering medium, transmitting a laser beam through the first optical fiber and into the scattering medium, and transmitting light scattered by the scattering medium through the second optical fiber. The quarter pitch, gradient index microlens transforms the beam emanating from the first optical fiber into a collimated laser beam.
Other objects and advantages of the systems disclosed herein will become apparent from the detailed description which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of a dynamic light scattering detection system including a back scatter probe utilizing homodyne detection in connection with the invention;
FIG. 1A is an enlarged, front elevation view of the probe shown in FIG. 1;
FIG. 2 is a schematical illustration of a back scatter probe utilizing both homodyne and self-beating detection in connection with the invention;
FIG. 2A is an enlarged, schematical illustration of a linear array of optical fibers positioned in the front focal plane of a GRIN microlens as shown in FIG. 2;
FIG. 3 is a schematic illustration of a system including a back scatter probe utilizing self-beating detection;
FIG. 3A is an enlarged, sectional elevation view of the probe shown in FIG. 3 positioned within a droplet formed at the end of a needle;
FIG. 4 is a schematical illustration of the intersection of the incident beam from a monomode fiber shown in FIG. 3 and the numerical aperture of a detection fiber;
FIG. 5 is an enlarged schematical illustration of a microlens on the tip of an optical fiber;
FIG. 5A is an enlarged schematical illustration of the free end of a monomode fiber having an expanded core portion;
FIG. 6 is a schematical illustration of an optical system used for testing fiber optic probes;
FIG. 7 is a graph illustrating the normalized intensity-intensity time correlation function obtained using the fiber probe illustrated in FIG. 1;
FIG. 8 is a graph illustrating the normalized intensity-intensity time correlation function obtained using the fiber probe illustrated in FIG. 2;
FIG. 9 is a graph illustrating the normalized intensity-intensity time correlation function obtained using the fiber probe illustrated in FIG. 3 (curve a). Curve b shows the lack of spatial coherence when a back scatter probe with two monomode optical fibers positioned side by side is used; and
FIG. 10 is an enlarged, schematical illustration of a back scatter fiber optic Doppler anemometer according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
1. Temporal Correlations for Brownian Motion
The derivation of the theoretical model derived in the study of Brownian motion and self-propelled organisms is possible by assuming that the scatterers are point sources and move independently of each other. For plane coherent monochromatic light of constant intensity incident on a collection of particles, the total scattered electric field in the direction Θ is ##EQU1## where E m 0 is the amplitude of the scattered electric field due to the m'th particle and is a function of the particle radius, scattering angle and refractive index, Φ m (t) is the instantaneous phase of the scattered field at time t due to the m'th particle and indicates the precise position of the particle, ω o is the angular frequency of the incident optical wavefield and j=√-1.
The unnormalized first order electric field correlation for the scattered field is
c(τ)=<E.sub.s.sup.* (t)E.sub.s (t+τ)> (2)
where * denotes the complex conjugate and <.>denotes a temporal average. Substituting equation (1) into (2) gives ##EQU2##
In the above expression the summation is over all the particles of the scattering ensemble. The phase of the field due to the m'th particle is
Φ.sub.m (t)=Q.r.sub.m (t) (4)
where r m (t) is the position vector of the m'th particle at time t and the Bragg vector Q is related to the scattering angle according to ##EQU3## where n is the refractive index of the host medium and λ o is the free space wavelength of the incident optical wavefield.
In general, equation (1) is only applicable to particles which are small compared with the wavelength of light. If L is the maximum dimension of the particle then 4 QL <1. For back scatter this gives an upper limit of 0.15 μm. However, it has been found that in practice the size of the particle may be considerably larger before diffraction effects due to particle size become significant.
If the particles are assumed to be identical, that is, E m o =E n o =E o , and the contribution from the m'th and n'th particle are statistically independent, then equation (3) reduces to : ##EQU4## where r' (τ)=r(t+τ)-r(t). If v(t) is the velocity of the particle at time t then ##EQU5##
The entire problem now rests in evaluating the expectation on the right hand side of equation (7). For brownian motion, equation (7) reduces to:
c(τ)=N|E.sup.o |.sup.2 exp(-Q.sup.2 D.sup.o τ) (8)
where D o is the translation diffusion coefficient at infinite dilution and is related to the frictional coefficient, f, through the Stokes-Einstein relation ##EQU6## where k is Boltzman's constant and T is the absolute temperature. In the case of spherical particles of radius a
f=6πηa (10)
where η is the intrinsic viscosity of the host medium.
If the particles in suspension are not identical, then equation (8) has to be modified to account for the spread in sizes. Assuming that N(a) is the number distribution in particle radius, then the electric field autocorrelation function becomes, ##EQU7##
By defining a laser light scattering size distribution, f(a)=N(a)|E o | 2 the autocorrelation function becomes ##EQU8##
It is common practice to use the substitution ##EQU9## to rewrite the above equation in the normalized form ##EQU10## where G(Γ) is known as the characteristic linewidth distribution function. The inversion equation (13), Laplace transform inversion, has been the subject of numerous studies and is the first step in the inversion of experimental measurements of the scattered light autocorrelation function before the size distribution or the molecular weight distribution can be determined.
The particle size distribution, N(a), can be determined from the characteristic linewidth distribution, G(Γ) using the following transformations. Firstly, the laser scattering distribution, f(a) is computed given the temperature, T in degrees Kelvin, the intrinsic viscosity η in Kg. (μm) -1 . sec. -1 , and refractive index of the solvent. The abscissa of G(Γ) are scaled by using ##EQU11## where a is the particle radius in microns, Q(μm. -1 ) is the Bragg vector as defined by equation f(5) and the Boltzman's constant k=1.38×10 -111 Kg. (μm) 2 sec -2 . The ordinates are scaled to give
f(a)=Γ.sup.2 G(Γ)
Now if the scattering amplitude |E o | 2 , the particle radius, the ratio of the particle to solvent refractive index, and the scattering angle are known, then we can scale the abscissa of f(a) to give the particle size distribution, N(a) by ##EQU12##
Intermediate distributions should be normalized to unity area before applying the appropriate scaling factors.
2. Self-Propelled Motion-Spermatozoa and Bacteria
For particles with linear velocities that remain unchanged over the measurement time relevant to the scattering experiments, the phase integral in equation (7) reduces to ##EQU13## where the velocity of the particle is maintained over distances that are long compared with Q 1 . In the absence of external forces and assuming an isotropic velocity distribution, evaluation of the expectation <>in equation (7) gives ##EQU14## where P s (v) is the distribution of swimming speeds to be recovered from measured correlation functions.
3. Spatial Coherence Considerations--The Diffraction Approach
One of the essential components of a successful dynamic light scattering apparatus is the detector module, which usually includes a series of distributed optical elements placed outside the scattering cell. The lenses and pinholes are arranged to define a certain angular uncertainty (or resolution) and an effective entrance pupil. The effectiveness of the detector assembly for DLS is measured by the light beating to shot noise ratio (more commonly referred to as the spatial coherence factor, β). It is now standard practice to design the detector module so that the ratio of the coherence area to the detector area is less than unity. However, the derivation of the spatial coherence requirements is based on a treatment of the scattering volume as a quasimonochromatic two dimensional spatially incoherent source, whose area is a projection of the scattering volume in a plane perpendicular to the direction of observation. The latter condition ensures that the coherence area is independent of the scattering angle. In actuality, the scattering volume is a three dimensional source and at least one of the three dimensions could change with the scattering angle. The coherence area is usually expressed as a product of the coherence solid angle, Ω coh and the square of the distance between the scattering center and the detector. There are several known ways of deriving expressions for the coherence solid angle by treating the scattering volume to be a three dimensional source. In a rectilinear coordinate system, consider the propagation of a linearly polarized, in the x-direction, laser beam in the z-direction and that the scattering is confined to the y-z plane. Derivation of Ω coh can be divided into two planar coherence angles (ΔΘ) coh and (Δφ) coh in the y-z and x-k s planes, respectively--where k s is the scattering vector. The diffraction approach for computing the coherence angles is based on the fact that coherence vanishes when relative phases of the waves reaching the observer from any two points on the extended source changes by an amount ±π as the observer moves from a position of perfect coherence to that of complete incoherence. The source points that produce the maximum relative phase change are determined by the extremal dimensions of the source as seen by the observer. In DLS, an incident laser beam has a circular cross-section of diameter, D I , and the length, L z , of the scattering volume is a function of the scattering angle. In general, the shape of the scattering volume formed by two intersecting cylinders is some solid ellipsoid, which approaches a parallelepiped, for D I <D A , where D A is the diameter of the interrogating detection beam. By considering the total relative phase arising from two extremal points in the scattering region, an expression for the planar coherence solid angle can be derived: ##EQU15##
4. Fiber Optic Probes for the Back Scatter Regime
FIG. 1 shows a compact back scatter optical probe 10 which combines the delivery of a Gaussian laser beam to a scattering medium and a homodyne receiver system in a single compact optical head. In this embodiment of the invention, a quarter pitch, graded index (GRIN) microlens is used to separate the transmitted and detected beams, as opposed to a fiber directional coupler. The GRIN microlens also provides additional control of the size of the scattering volume.
Light from a laser source 12 is launched into a polarization maintaining monomode optical fiber 14 by means of either a GRIN microlens 16 or a microscope objective. The other end of the optical fiber is mounted into a glass capillary 18 (alternatively a stainless steel ferrule or any other suitable material), which is actively aligned by means of V grooves 20 in a brass ferrule 22. A quarter pitch GRIN microlens 24 epoxied into the ferrule 22 transforms the light emanating from the fiber mounted in the lass capillary 18 into a collimated laser beam at the output face 26 of the GRIN microlens. The waist, ω o is related to the input waist ω i , which is equivalent to the core radius of the optical fiber 14 by the relation ##EQU16## where N o and √A are the axial index of refraction and the quadratic index constant of the microlens, respectively, and λ is the wavelength of light. The divergence angle of the Gaussian beam is given by ##EQU17##
The front face 28 of the GRIN microlens 24 is antireflection coated but the back face 26 is not antireflection coated. Consequently, the back face 28 acts like a partial mirror, thereby providing a diminished image of the input fiber at a point symmetrically located about the optical axis. An optical fiber 30 mounted to a glass capillary 32 positioned at this location will receive the back reflected signal 34 from face 26 together with the back scattered signal from particles near the tip of the probe body 36. A monomode, polarization maintaining fiber is preferred for homodyne detection. The two fibers are epoxied into a bushing 38, which fits into the probe body 36, and a heat shrinkable tube 40 is used to relieve strain on the fibers. The back reflected and scattered signals are guided to a photodetector 42 by another polarization maintaining fiber 30 and a GRIN microlens 44. The photogenerated current at the output of a suitable photodetector is processed by a data acquisition system 46 to give the normalized first order autocorrelation of the scattered light.
The composite probe is no more than 5 mm. in diameter and 50 mm. in length. The scattering angle Θ is given by ##EQU18## where Δy is the separation between the two glass capillaries 18 and 32, and ω i is radius of the core of the optical fiber 30. The choice of the GRIN microlens 24 and a detector fiber 30 are dictated by the strict spatial coherence requirement discussed earlier.
FIGS. 2 and 2A show a multiple fiber back scatter probe 50. A linear array of eleven optical fibers is formed onto brass ferrule 52 comprising lower 54 and upper 56 portions. One of the fibers 58 is a monomode optical fiber which is used for delivering light from a laser source to the scattering medium by means of a quarter pitch GRIN microlens. The other ten optical fibers 60 are identical and have a core diameter of eight microns, which makes them multimode at the wavelength of operation. The fibers are held in position by means of epoxy 62. The fiber array mounted in the ferrule 52 is positioned in the back focal plane of the quarter pitch GRIN microlens 64 which is mounted in the probe body. The eleven fibers are grouped into a cable 66 which is secured to the probe ferrule 52 with a heat shrinkable tube 68. As above, light from a laser source is launched into the transmitting fiber by means of a suitable lens 70. Fibers 60 adjacent to the transmitting fiber 58 receive the scattered signal 72, which is transmitted to the photodetector 75 by means of the optical fibers and quarter pitch microlenses 74. The scattering angle for the p'th fiber as measured from the transmitting fiber is given by ##EQU19## where r f is the core radius of the receiving optical fiber (=ω i for the receiving fiber), and Δy is the separation between the fibers in array. The waist of the transmitted laser beam 76 is ##EQU20## where r i f is the core radius of the transmitting fiber. In this configuration the front 78 and back 80 surfaces of the microlens 64 are both antireflection coated, thereby reducing the amount of flare in the microlens. Flare reduces the self-beating efficiency of the detection process and should be avoided. The second through tenth fibers 60, together with the GRIN microlens, provide a self-beating detection system. Multimode fibers are preferred for self-beating detection. The eleventh fiber 60, which is located at the mirror image of fiber 58, provides homodyne detection because of the additional back reflection component from the back surface 80.
Both the above configurations of a back scatter anemometer for dynamic light scattering have unique distinguishable features that the current state-of-art systems do not possess. Firstly, the costly directional coupler has been eliminated. Secondly homodyne and self-beating measurements of the scattered light can be performed over a range of angles from 156° to 177.6° by means of a single probe with a resolution of 2.4°±0.08°. Thirdly the use of a quarter pitch GRIN microlens allows the delivery of a collimated laser beam to the scattering system. Self-beating measurements, which were not possible within the same probe body until the present invention, are usually preferred over homodyne schemes.
The back scatter probe 90, shown in FIG. 3, does not require the use of a GRIN microlens or any other lens. Realization of this configuration follows from consideration of the spatial coherence requirements as discussed previously. For efficient self-beating detection, the scattering region, which is a three dimensional volume source, must have the magnitude of the complex degree of coherence |γ 12 (τ')| as close as possible to unity. In the extreme limits a point scattering region or alternatively a point detector both satisfy this condition, but neither is possible. In practice, then, the coherence requirements translate into approaching this condition. However, another conflicting requirement is that of the need for a finite scattering volume in order to observe the scattering process, that is the value of unity for |γ 12 (τ')| may not be desirable. The size of the scattering volume and the size of the detector are coupled together; the effects of both cannot be independently assessed. Based on the analysis presented previously, the coherence angle (equation (15)) approaches a maximum value at a scattering angle of 90° and zero in the forward and back scattering regions (Θ=0,π). In a conventional light scattering spectrometer, a laser beam is focussed into the scattering region by means of a convex lens to produce a waist size in the range of 100 to 200 microns. Stronger focussing, though desirable, can lead to distortions in the measured correlation function, because the length of the scattering region seen by a conventional detection system is usually much larger than the incident beam diameter (alignment is easier). Consequently the phase curvature leads to pronounced distortions in the forward direction. The laser beam profile emanating from the end of a monomode fiber (at λ=475 nm. in water) has a Gaussian distribution with a waist of 4 microns, which gives a coherence solid angle, using equation (15), of 13.5 mrad. at a scattering angle of 150° and a coherence solid angle of 6 μrad. at a scattering angle of 179°. An optical fiber with a waist size of 4 μm. in water has an acceptance angle of 39 mrad. This means that a back scatter probe using two optical fibers without a GRIN microlens will give an efficient self-beating detection system. An additional advantage will be the extremely small size of the subsequent probe, less than 0.5 mm in diameter. This has considerable significance in the study of DLS probes for a microgravity environment. For example, the growth of protein crystals in a microgravity environment involves suspending droplets from hypodermic needles. Using this embodiment of the invention, it will be possible to insert the above probe through the needle 91 into the droplet and monitor the kinetics of the crystallization process, in situ, as shown in FIG. 3A.
In FIGS. 3-4, a laser beam 92 from a laser source 93 is delivered to the scattering region by means of a monomode optical fiber 94, and a launching lens 96. The scattered signal is detected by means of a multimode optical fiber 98, a GRIN lens 100 and a photodetector 102. The photodetector is connected to a data acquisition system 103. In this configuration, a probe body 104 is shown in unnecessarily more complexity than required. (The optical fibers may simply be epoxied to a wedge so that they are properly oriented with respect to each other). Bushing 106 attaches the two fibers 94 and 98 to the probe body 104. The fibers are terminated in glass ferrules 108 and 110 and mounted in a holder 112, which is attached to probe body 104. The incident beam 92 has a Gaussian profile as described earlier, and consequently the detection fiber collects scattered light over a range of scattering angles defined by the numerical aperture 114 of the multimode fiber 98. The scattering region 116 is defined by the intersection of beam 92 and aperture 114.
Additional control of the beam waist of the laser light emanating from the monomode fiber of probe 90 may be controlled by fabricating a microlens on the tip of the fiber as shown in FIG. 5. This gives additional flexibility for optimization of optical probes for particular applications. In FIG. 5, a monomode fiber 120 has a core region 122 which supports a Gaussian laser beam, and a cladding region 124 which is much larger than the core. A microlens 126 is formed on the end of the monomode fiber by dipping the fiber end into a negative photoresist while the fiber core carries >=0.1 mw of He-Ne laser light. The desired waist 128 of the transmitted laser beam can be produced by multiple dips and actively monitoring the laser beam radiation pattern 129.
A second method for controlling the characteristics of the optical wavefield emanating from the tip of the fiber involves heating of the fiber end such that the core of the fiber diffuses into the cladding region. This results in a flaring of the effective mode volume near the tip of the fiber, thereby increasing the effective waist, and reducing the divergence of the transmitted laser beam. An optical fiber 120' as shown in FIG. 5A is particularly suitable for a probe as shown in FIG. 3. The flaring of the core 122' near the tip of the fiber through diffusion into the cladding material 124' reduces beam divergence, and allows the transmitting fiber to be oriented more closely to parallel with the receiving fiber than the arrangement shown in FIG. 3. This allows the probe to be even smaller.
Fiber optic probes described above can be tested by employing the optical system shown in FIG. 6. A laser beam 130 from a Spectra Physics He-Ne (SP124B) laser is launched into a transmitting optical fiber 132 by means of 20×microscope objective 134. An aqueous suspension 136 of 0.176 μm nominal diameter latex spheres with a concentration of ≈ -8 g/ml. may be used to evaluate the accuracy of particle sizing. The free ends of the optical fibers used as receivers are terminated using SMA type 2 connectors 138 and coupled to the face plate photomultiplier housing 140 by employing a quarter pitch GRIN microlens. An interference filter (not shown) is positioned within the face plate and in front of a photocathode. A digital correlator 142 is used to measure the intensity-intensity correlation function, G.sup.(2) (τ) for each of the three fiber optic probes described above. An amplifier discriminator 144 is connected between the digital correlator and photomultiplier. In a commercial unit, semiconductor lasers and photon detectors may be employed to gain considerable cost and size reduction.
The photomultiplier 140 produces at its output a train of photo-electron pulses n(t), which is proportional to the instantaneous intensity of the optical radiation reaching the photocathode surface. The photon correlator measures photon correlation <n(t)n(t+τ)>, which is proportional to the intensity-intensity time correlation G.sup.(2) (τ). In general, the instantaneous photon count rate n(t) has two components, one corresponding to the coherent addition of field amplitudes arising from different points within the scattering volume and the second corresponding to the incoherent addition of the field amplitudes. The ratio of the coherent component to the total count rate is a measure of the magnitude of the complex degree of coherence, which represents the self-beating efficiency. Thus, the spatial coherence factor β' is defined by ##EQU21## where <ns>and <n>are scattered photon signal and total count rates, respectively. By considering the optical signal reaching the photomultiplier to contain a local oscillator signal .sup.η / ., the unnormalized intensity-intensity time correlation function is given by
G.sup.(2) <η>'.sup.2 +2<η.sub.s >η.sub./o g.sup.(1) (τ)+<η.sub.x >.sup.2 |g .sup.(1) (τ)|.sup.2
where <n>'=<n>+n /o , g.sup.(1) (τ) is the normalized first order electric field correlation. Normalization with the baseline <n>' 2 gives ##EQU22##
For a self-beating experiment, η/o=0, the first term in the above equation goes to zero giving the Siegert relation. For a homodyne detection with <n s ><<n /o , the second term in the above equation vanishes. FIGS. 7, 8, and 9 show the subsequent intensity-intensity correlation function measured using the probes described in FIGS. 1, 2, and 3, respectively. The intercept of these curves gives the self-beating efficiency parameter, β', which is largest for probe 90 and is approaching the theoretical limit of unity. In FIG. 9, curve (a) corresponds to probe 90 in FIG. 3 with ΔΘ=23°, curve (b) represents measurements of G.sup.(2) (τ) with a back scatter probe comprising two monomode fibers positioned side by side (ΔΘ=0). This demonstrates, as discussed above, the poor light beating efficiency, and as such this latter probe is unsuitable for DLS. The design of probe 90 accordingly involves considerable understanding of the spatial coherence requirements.
The correlation data described above is analyzed using a non-linear least squares curve fitting procedure based on the method of cumulants. Estimates of particle size and η' are summarized in Table 1. β' is preferably at least about 0.5.
TABLE 1______________________________________Analysis of correlation data in FIGS. 7, 8, and 9Probe Θ Diameter (nm) β'______________________________________10 161.0 161 0.7750 177.6 178 0.4590 157.0 193 0.96______________________________________
OTHER APPLICATIONS
The accuracy of fiber probes 10, 50, and 90 can be demonstrated by measuring the size of polystyrene spheres. However, these probes can be used for measurements of the swimming speed distribution of microorganisms such as bacteria. There are several other applications of the multiple fiber probe described above. Some of these are discussed below.
Measurements of the scattered light intensity at closely packed forward angles is very important. This can be achieved with conventional spectrometers using a single fiber probe. However, the ability to have a single fiber probe providing a parallel filtering of the scattered optical wavefield prior to detection will be a very significant addition and improvement to existing techniques. For example, the back scatter probe described above can be used in the forward region without any changes. In this region the multiple fiber probe acts as a composite receiver. However, incident laser light must be introduced into the scattering region by other means. The angular separation, 2.4° for the probe described above, and the total range can be improved substantially by using a smaller separation between the fibers and a large number of fibers, respectively. It should be noted that while a linear array of fibers is employed in the above-described example, any other coplanar arrangement of the free ends of the fibers can alternatively be utilized.
In FIG. 10, two polarization maintaining, monomode optical fibers 150 and 152 mounted in suitable ferrules 154 are actively aligned to the antireflection coated front surface 156 of a quarter pitch GRIN microlens 158 which delivers two Gaussian laser beams 160 and 162 to the scattering medium. The back surface 164 of the microlens 158 is also antireflection coated. A particle 166 moving parallel to the front surface 164 crosses the two beams 160 and 162, thereby producing a scattered signal 168 comprising two signals corresponding to each of the two incident beams. The scattered signal in the back scatter direction is focussed onto a multimode detection fiber 170 mounted in the ferrule 154 and positioned on the optical axis 172 of the probe and in contact with the front surface 156 of the microlens 158. The system 169 for launching light into the fibers 150 and 152 is as described previously with respect to FIG. 6, as is the detection system 174. This embodiment of the invention is suitable for applications ranging from blood flow to mapping of velocities in supersonic wind tunnels. With two incident beams, one color system, one component of flow, parallel to the surface of the microlens, is measured. The probe could be modified to measure two components of flow by using a two color system. This is achieved by introducing a third transmitting fiber and a second receiver.
Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.
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A system for determining the physical properties of materials through the use of dynamic light scattering is disclosed. The system includes a probe, a laser source for directing a laser beam into the probe, and a photodetector for converting scattered light detected by the probe into electrical signals. The probe includes at least one optical fiber connected to the laser source and a second optical fiber connected to the photodetector. Each of the fibers may adjoin a gradient index microlens which is capable of providing a collimated laser beam into a scattering medium. The position of the second optical fiber with respect to the optical axis of the probe determines whether homodyne or self-beating detection is provided. Self-beating detection may be provided without a gradient index microlens. This allows a very small probe to be constructed which is insertable through a hypodermic needle or the like into a droplet extending from such a needle. A method of detecting scattered light through the use of a collimated, Gaussian laser beam is also provided. A method for controlling the waist and divergence of the optical field emanating from the free end of an optical fiber is also provided.
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TECHNICAL FIELD
The present invention relates to slide processing apparatus, and more particularly to improvements in heaters for slides for biological reaction analysis slide processing systems.
BACKGROUND ART
Immunostaining and in situ DNA analysis are useful tools in histological diagnosis and the study of tissue morphology. Immunostaining relies on the specific binding affinity of antibodies with epitopes in tissue samples, and the increasing availability of antibodies which bind specifically with unique epitopes present only in certain types of diseased cellular tissue. Immunostaining requiring a series of treatment steps conducted on a tissue section mounted on a glass slide to highlight by selective staining certain morphological indicators of disease states. Typical steps include pretreatment of the tissue section to reduce non-specific binding, antibody treatment and incubation, enzyme labeled secondary antibody treatment and incubation, substrate reaction with the enzyme to produce a fluorophore or chromophore highlighting areas of the tissue section having epitopes binding with the antibody, counterstaining, and the like. Each of these steps is separated by multiple rinse steps to remove unreacted residual reagent from the prior step. Incubations typically are conducted at around 40° C., while cell conditioning steps typically are conducted at somewhat higher temperatures, e.g. 90-100° C. In-situ DNA analysis relies upon the specific binding affinity of probes with unique nucleotide sequences in cell or tissue samples and similarly involves a series of process steps, with a variety of reagents and process temperature requirements.
Automated systems have been proposed to introduce cost savings, uniformity of slide preparation, and reduction of procedural human errors. Stross, W. et al, J. Clin. Pathol. 42: 106-112 (1989) describes a system comprising a series of baths positioned under the circumference of a circular, rotatable disc from which slide trays are suspended. The disc is lifted to lift slide trays from their baths, turned to position the slide trays above the next consecutive bath, and lowered to immerse the slide trays in the baths. This operation can be automated with suitable timers and switches. This system exposes each of the slides to the same treatment and relies on dipping for application of reactants and rinsing.
Stark, E. et al, J. Immunol. Methods. 107: 89-92 (1988) describes a microprocessor controlled system including a revolving table or carousel supporting radially positioned slides. A stepper motor rotates the table, placing each slide under one of the stationary syringes positioned above the slides. A predetermined volume of liquid, determined by a dial, is delivered to a slide from each syringe. Microprocessor controls are provided.
Cosgrove, R. et al, ACL. pp 23-27 (December, 1989) describe an immunostaining apparatus for auto-pipetting reagents into a slide well from a carousel holding up to 18 reagent vials. Below each well, a coverplate spaced from the surface of each slide provides cover and defines a reagent flow channel. The slides are suspended at a steep angle. Reagent from the well flows downward over the slide surface. A row of slides are suspended for sequential treatment. Washing is accomplished by a 3 to 4 minute continuous running wash over the sample, yielding an estimated 20:1 wash/reagent ratio.
Brigati, D. et al, J. Histotechnology 11: 165-183 (1988) and Unger, E. Brigati, D. et al, et al, J. Histotechnology. 11: 253-258 (1988) describe the Fisher automated work station using capillary gap technology. A coverplate is placed over the slide, forming a capillary gap. Liquid is introduced into the capillary gap by placing the lower edge of the plate-slide pair in a liquid. Liquid is removed by placing the lower edge of the plate-slide pair on a blotter. The system is further described in U.S. Pat. Nos. 4,777,020, 4,798,706 and 4,801,431. The previously known devices are listed in their performance and unable to satisfy the needs for automated, high precision immunohistology.
The foregoing discussion of the prior art derives in large part from U.S. Pat. No. 5,654,200 to Copeland et al., who describe an automated biological processing system comprising a reagent carousel cooperating with a sample support carousel to apply a sequence of preselected reagents to each of the samples with interposed mixing, incubating, and rinsing steps cooperating therewith. This patented automated biological processing system, which is available from Ventana Medical Systems, Inc. of Tucson, Ariz. includes a slide support carousel having a plurality of slide supports thereon and drive means engaging the slide support carousel for consecutively positioning each of a plurality of slide supports in a reagent receiving zone. The reagent carousel has a plurality of reagent container supports thereon and drive means engaging the reagent carousel for rotating this carousel and positioning a preselected reagent container support and associated reagent container in a regent supply zone. The apparatus has a reagent delivery actuator means positioned for engaging a reagent container positioned on a container support in the reagent supply zone and initiating reagent delivery from the reagent container to a slide supported on a slide support in the reagent receiving zone.
FIG. 1 , which largely corresponds to FIG. 3 of U.S. Pat. No. 5,654,200 is a partial exploded isometric view of an automated biological processing system, with the cabinet, liquid and air supply tubing and electrical wiring omitted in the drawings for the purposes of clarity.
The apparatus has an upper section 2 , intermediate section 4 and lower section 6 . In the upper section 2 , reagent bottle support carousel 10 is mounted for rotation about its central axis on upper support plate 8 . Reagent bottles 12 required for the immuno-histochemical reactions to be conducted during slide treatment cycle are supported by the carousel 10 , mounted in reagent bottle receptors 11 . These receptors 11 are configured to receive volumetric pump outlet tubes (not shown). The receptors 11 are preferably equally spaced in a circular pattern axially concentric with the carousel axis. The number of receptors 11 provided should be sufficient to accommodate the number of different reagent bottles 12 required for a cycle or series of cycles. The carousel 10 is rotated by the stepper motor 14 and drive belt 16 to a position placing a selected reagent bottle 12 in the reagent delivery position under an air cylinder reagent delivery actuator 18 over a slide to be treated with reagent. Reagent tray motor driver 20 is connected to stepper motor 14 .
The intermediate section 4 comprises support plate 22 upon which the slide support carousel 24 is rotatably mounted. The carousel 24 supports slide supports 26 . In the intermediate section 4 , a stepper motor 48 rotates the slide support carousel 24 , engaging drive belt 25 engaging the perimeter of the slide support carousel 24 . Splash guard 50 is a wall which surrounds the sides, back and part of the front of the carousel 24 , and contains liquid spray and droplets produced in the processing. Splash guard 50 extends upward from the intermediate plate 22 to a position adjacent the upper plate 8 , leaving an air flow gap between the upper edge of the splash guard 50 and the underside of the plate 8 . Lower section 6 includes slide carousel stepper motor driver 72 and relay 74 , power supplies 76 and 78 , and control systems all mounted on plate 40 .
Referring to FIGS. 2 and 3 , slide support 26 comprises a molded plastic base 80 on which is mounted a metal plate 82 . An electrical resistance heater shown in phantom at 84 is mounted in direct contact to the underside of metal plate 82 . Corner pins 86 locate a specimen carrying glass slide 88 on the surface of metal plate 82 . Metal plate 82 has a top surface that is essentially flat and smooth. Flatness and smoothness facilitates glass plate position stability and thermal conduction uniformity.
In practice, water and other fluids employed in the slide processing may spill over the edges of the slides, and work their way under the slides where the fluids may boil, causing the slides to “pop” or dislocate. Moreover, since heater surfaces are not perfectly flat, in order to insure good thermal contact between metal plate 82 and glass slide 88 , a thin layer 90 of oil may be applied to the top surface of metal plate 82 . However, using oil as an interfacial heating medium, may exacerbate the problem of slide popping or dislocation due to gas formation from water or other fluid getting under the slide, mixing with the oil and then boiling off in an uncontrolled fashion. Dislocation of a slide may cause that slide to set up on a post, thereby compromising the processing of that one slide, or in a worse case scenario result in a domino or train wreck effect where the one dislocated slide hits a neighboring slide causing that slide to dislocate, and so forth.
BRIEF DESCRIPTION OF THE INVENTION
The present invention overcomes the aforesaid and other disadvantages of the prior art, by patterning the slide heater upper surface and/or the glass slide underside surface with ridges or slots, whereby gas bubbles generated by boiling of water trapped between the slide heater and the slide may be channeled, to edges of the slide heater, where the gas may escape or vent without lifting or otherwise dislocating the glass slide.
BRIEF DESCRIPTION OF THE DRAWINGS
Further features and advantages of the present invention will be seen from the following detailed description, taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a partial exploded isometric view of a prior art automated slide processing apparatus;
FIG. 2 is a top plan view of a prior art slide support and heater;
FIG. 3 is a side elevational view of a prior art slide support and heater;
FIG. 4 is a top plan view of a slide support heater made in accordance with a first embodiment of the present invention;
FIG. 5 is a side elevational view, in cross-section, of a slide support heater of FIG. 4 ;
FIG. 6 is an enlarged detail view, in cross-section, of a portion of the slide heater of FIG. 5 ;
FIG. 7 is a view similar to FIG. 4 showing details of an alternative slide support heater in accordance with the present invention;
FIG. 8 is a side elevational view of the slide support heater of FIG. 7 ;
FIG. 9 is an enlarged detail view of the slide support heater of FIG. 8 ;
FIGS. 10 and 11 are views, similar to FIG. 9 , of yet other embodiments of slide support heaters made in accordance with the present invention;
FIGS. 12-14 are views similar to FIG. 4 of yet other embodiments of slide support heaters made in accordance with the present invention;
FIGS. 15-17 are views similar to FIGS. 4-6 , respectively, of still another alternative of the present invention; and
FIGS. 18 and 20 and 19 and 21 , are views similar to FIGS. 6 and 17 , respectively, of still other alternative of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is based on the discovery that ridges or slots formed on the upper surface of the slide heater and/or on the lower surface of the slides serve to route or channel bubbles formed by the boiling of water or other fluid trapped between the slide heater and slide, to edges of the slide, where the bubbles may vent without dislodging the slide. As mentioned supra, heater surfaces are not perfectly flat. Thus, slight variations in surface heaters may result in a bias or pooling of gas, i.e., steam bubble migration to low areas, and/or in the case of a slide having an interfacial layer or oil, into and through regions of deeper oil. In the case of prior art slide heaters, the migrating gas could pool to a vapor pocket which could “pop” the slide. The present invention takes advantage of the phenomena of gas bubble migration by creating channels for the gas which terminate at open edges of the slide heater. Gas bubbles forming on the surface of the heater migrate to the channels, displace any oil present in the channels, and run to the ends of the channels, where the migrating gas bubbles vent harmlessly from the slide heater edges without dislodging the slide.
An important feature and requirement of any slide heater is to provide substantially uniform heating across a slide since non-uniformity of heating could result in unreliable analytical results. Thus, the general wisdom has been to make heater surfaces and slide surfaces as smooth as possible, i.e., so as to achieve maximum contact or match. Unexpectedly, it has been found that up to about 50% of the slide heater upper surface and/or glass slide may be removed, i.e., by patterning with channels or slots, without adversely affecting thermal conduction uniformity and temperature uniformity distribution across the interface between the slide heater and the glass slide. In other words, provided about at least 50% of the slide heater and glass slide facing surfaces are retained, there is sufficient thermal conduction uniformity between the heater and the slide to mediate slight thermal differences between the low and high parts of the slots or channels resulting in substantially uniform heating of the slide.
The slots or channels may be formed by machining, casting or etching, and should be spaced close enough together so that nucleating gas bubbles do not have to travel too far before reaching a slot or channel. Typically, the slots or channels are spaced about 2 to 5 millimeters on center, preferably about 3 to 4 millimeters. Spacing the slots or channels more than about 10 millimeters apart, on center, may permit gas bubble pooling and thus may not provide sufficient glass slide stability. On the other hand, forming slots or channels closer than about 3 millimeters, on center, may result in removal of a greater percentage of the surface than ideal for uniform thermal conductivity, depending on the width of the slots or channels. Also, placing the slots or channels too close together, and/or forming a large number of narrow slots or channels, adds to initial fabrication costs and may make cleaning more difficult; and, making the channels or slots overly narrow could restrict free venting of gas.
Preferably the slots or channels are similar in size and shape, and run parallel or near parallel to one another, and preferably run from side edge to side edge of the heater. The aspect ratio of the slots or channels per se appears to have little affect on the ability to gather and vent nucleating gas bubbles. Nor does the cross-sectional shape of the slots or channels significantly affect the ability to gather and vent nucleating gas bubbles provided the slots or vents are not overly narrow. As a practical matter, rounded or square edge slots or channels, which could be formed simply by machining, are preferred. Alternatively, the slots or channels can be cast.
Referring now to FIGS. 4-6 , there is shown a first embodiment of slide heater made in accordance with the present invention. (For clarity, details other than the heater surface have been omitted). The heater 100 has an upper surface 102 in which are formed 15 substantially parallel grooves 104 . Slots or channels 104 have a rounded bottom of about 0.4 millimeter radius, and run from side to side of the heater 100 . The slots or channels 104 are approximately 0.25 millimeter at their deepest point, and are spaced at about 3 millimeters on center.
Referring to FIGS. 7-9 , where there is shown an alternative slide heater made in accordance with the present invention. The FIGS. 7-9 embodiment differs from the embodiment of FIGS. 4-6 in that the slots or channels are “v” shaped.
In yet another embodiment illustrated in FIG. 10 , the slots or channels are rectilinear in shape, and have a depth-to-width ratio of about 0.2 to 2, preferably about 0.3 to 0.5. FIG. 11 is similar to FIG. 10 , in which the slots or channels have a different depth-to-width ratio.
Various changes may be made in the invention without departing from the spirit and scope thereof. For example, as shown in FIG. 12 , the slots or channels may be formed blind at one end.
It also may be possible to orient the slots or channels to run the length rather than the width of the heaters ( FIG. 13 ), or at a diagonal ( FIG. 14 ). However, doing so increases the length of the slots or channels, and could result in pooling of gas bubbles in an individual slot or channel, as well as increased transit time to the edges of the slots or channels before the gas could be vented. Accordingly, for optimization purposes, it is preferred that the slots or channels are made as short as possible and run side to side with no interconnections from slot to slot, i.e. the slots should not intersect. In yet another embodiment of the invention, illustrated in FIGS. 15-17 , slots or channels 200 , similar in arrangement to slots or channels 104 , may be provided on the underside of a glass slide 202 , and provide similar function.
Yet other changes may be made without departing from the spirit and scope of the invention. For example, instead of machining or casting referring to FIGS. 18-21 , slots in channels in the interface surface of the heater or the glass slide, spaced raised regions 300 may be formed on the interface surface of the heater 302 on the glass slide 304 by applying a thermally conductive decal much as a patterned metal foil 306 , or by printing with a thermally conductive ink or coating 308 or the like, so as define slots or channels therebetween.
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A slide heater for use in a slide processing apparatus in which an interface surface between the slide heater and the slide has a plurality of slots or channels terminating in an edge thereof, for gathering and venting gas bubbles.
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BACKGROUND OF THE INVENTION
(1) Technical Field
This invention is concerned with methods for making semiconductor devices, and more particularly, to the curing of photoresist films used in such fabrication.
(2) Description of the Prior Art
U.S. Pat. No. 5,431,700 issued Jul. 11, 1995 to Ben J. Sloan discloses a wafer baking and chilling apparatus which heats the wafers with a bake plate from the front side. The invention also used gas flow.
U.S. Pat. No. 5,306,653 issued Apr. 26, 1994 to Chang W. Hur shows a method of baking photo resist to make it flow to a desired width.
U.S. Pat. No. 4,814,243 issued Mar. 21, 1989 to David H. Ziger shows an image reversal process using a bake process in an oven.
A wafer for the manufacture of semi-conductive elements is subjected to numerous sequenced operations during photolithography enables the fabrication of all its circuit elements. The use of a thin layer of photo resist on a wafer's surface in conjunction with photolithograhic masks provides the means to transfer the various masking layers onto the semiconductor wafer. The photolithographic mask selectively exposes a portion of photoresist film to actinic light while leaving the masked portion unexposed. The exposed portion makes the photoresist soluble in a base solution and insensitive to light. The unexposed portion is insoluble in the base solution and is photo sensitive.
The development of highly integrated circuit patterns with line widths and spacing in the submicron ranges places increasingly higher demands on image resolution capabilities of the photoresist. Processes involving film thickness, thickness uniformity, resist baking, and intermediate handling have become critical steps in the manufacturing of high speed integrated circuits.
SUMMARY OF THE INVENTION
In the processing of semiconductor wafers for forming integrated circuits, a thin film of material, for example, a photoresist that is suspended in a solvent, is applied to the surface of a wafer. To harden the material, the thin film must be baked and then cooled.
An object of the present invention is to reduce contamination of the wafer by the manner in which the wafer is supported from the back side.
Another object of the present invention is to increase the throughput of the baking process by integrating the hot and cold plates.
Still another object of the present invention is to improve the uniformity of photoresist thickness by controlling the space between the back side of the wafer and the hot plate.
Another object of the present invention is to provide additional front side heating using infra-red radiation which also improves photoresist thickness uniformity by means of direct photo resist heating versus using only the conventional back side plate contact method. The efficiency of back side conduction is dependent on the extent of contact resistance between wafer and hot plate as relating to the magnitude of heat transfer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a prior art illustration of a contact type photo resist baking system using a back side heating source.
FIG. 2 is a prior art illustration of a proximity type photo resist baking system using a back side heating source.
FIG. 3 is an illustration, of the present invention, showing a direct and horizontal front side photo resist baking system.
FIG. 4 is an example, of the present invention, showing a direct and vertical front side photo resist baking system.
FIG. 5 is an illustration, of the present invention, simply showing a curing chamber.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Aspects of the present invention consists of a method and apparatus for baking photo resist uniformly, with increased throughput and yield.
Contamination of a wafer during deposition of liquid photo resist lowers the yield for defect free devices. The wafer's total surface area is susceptible to contamination including its back side. After cleaning, the wafer is placed on a vacuum chuck which can be rotated at high speed. The wafer is centered on the chuck, secured to the chuck by vacuum and spun at a high speed. A measured quantity of photoresist is deposited on the spinning wafer. A combination of surface tension and forces resulting from spinning causes the liquid resist to spread into a uniform, thin film from which the solvents used to liquify the resist quickly escape by evaporation. The wafer is carefully removed from the spinner and placed in a heat controlled environment for baking.
In the semiconductor industry, a hot plate is routinely used for baking a photoresist coated wafer by resting its backside on the top surface of the hot plate. Photoresist baking is done in three steps. The first, "soft bake", is done after spinning and before exposure, the second, designated "post exposure bake", is done after exposure, and the third, "hard bake", is done ater development.
Referring now to FIG. 1 a conventional photoresist baking process, of the prior art, is shown. A wafer 12 after having a thin layer of photoresist 11 formed on its upper surface is placed within a controlled environment onto a hot plate 13 . The layer of photoresist 11 is cured by the transfer of heat from the wafer's backside to its top side. Heat conduction varies throughout the wafer with greater heat flow and curing occuring at the boundry layer above the points of contact between wafer and hot plate thereby causing a variance in the photoresist thickness relative to the wafer's top surface. Additionally, the wafer is more susceptible to defocusing during photolithographic exposure due to backside contamination.
FIG. 2 shows an indirect method, of the prior art, for curing photoresist using a hot plate 13 having interposing support elements 14 on its top surface thereby permitting a wafer 12 to be placed proximate to the top surface of the hot plate while resting on support elements 14.
Controlling thickness of photoresist is difficult because of the physical constraints regarding flatness, parallelism, and levelness during surface either contact or proximity backside baking techniques.
FIGS. 3 and 4, of the present invention, both illustrate a front side baking configuration. FIG. 3 shows a wafer 12 resting horizontally on a plurality of support members 23 with its photoresist surface 11 facing a curing source 25. FIG. 4 shows a wafer 12 held vertically by a rotatable vacuum chuck 24 with its photoresist surface 11 parallel to and facing a curing energy source 26.
The horizontal configuration as illustrated in FIG. 3, is used with a radiant infra-red lamp 25 for curing the photoresist during critical layer lithography steps. This combination results in a more uniform thickness because controlling the distance and intensity of a radiant energy source is easier than that of a conventional backside conducting hot plate. During non-critical layer lithography steps, a hot gas supply in place of the infra-red lamp, is directed towards the wafer to rapidly dry and cure the photo-resist. Still another configuration is used for the non-critical lithography steps. Using a hot plate with its heated surface facing the wafer's front side is also an optional heat source replacing the hot gas supply. A cooling feature is integrated into the hot plate thereby improving process throughput.
FIG. 4 showing a vertical rotating wafer, eliminates solvent outgas contamination, is used for both post exposure bake and hard bake. Back side contamination is also avoided since the wafer is in smallest contact with the vacuum chuck.
FIG. 4 illustrates the apparatus that is used for the process of hardening an emulsion 11 on a surface of a substrate 12 that has been actinically pattern exposed and developed. An emulsion hardening chamber which includes a radiant heat source 26 and a vacuum chuck apparatus 24 having a vertical and rotatable chuck holding member. A substrate 12 is placed in the hardening chamber and vertically secured to the vacuum chuck apparatus 24 by a vacuum acting against the back side of the substrate 12. The vacuum chuck is put into rotation thereby rotating the substrate 12 about its center axis. The radiant heat source 26 is turned on and heats the emulsion side of the substrate to an intended temperature. After heat hardening of the emulsion 11, the substrate 12 is cooled and removed from the vacuum chuck apparatus 24. The radiant heat source 26 is placed in front of the vacuum chuck apparatus 24 and at a suitable distance to allow for the loading and unloading of the substrate 12.
The radiant heat source is selected from a group consisting of a radiant lamp, or a hot gas, or a hot plate, and placed in front of the emulsion's surface. Cooling of the substrate after hardening the emulsion is done by turning off the radiant heat source and directing a cooling gas flow towards the emulsion.
The preferred method illustrated in FIG. 4 shows a substrate that is vertically held by vacuum making minimum contact with the vacuum chuck is rotated during the process of hardening the emulsion 11 on the front surface of the substrate 12 that has been actinically pattern exposed and developed. The method is used for both exposure bake and hard bake. Vertical processing of the substrate eliminates solvent outgas contamination and reduces backside contamination because of the substrate's minimum contact with the vacuum chuck 24. Integration of both hardening and cooling within the same operation improves product throughput.
FIG. 5 illustrates a curing chamber 41 having a controlled environment. Wafer 12 is placed into the curing chamber onto a support surface by way of a closeable opening 42. Evaporated solvents and the hot gas flow are collected through an exhaust port 43.
While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.
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A method and apparatus for curing a photoresist that is deposited in liquid form and spun on a surface of a wafer leaving a thin film to be cured. This invention teaches methods for curing the resist with improved thickness control using front side heating.
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This is a continuation of application Ser. No. 700,224, filed Feb. 11, 1985 abandoned.
FIELD OF THE INVENTION
This invention relates to chainstitch sewing machines having one or more loopers and, more particularly, to a mechanism capable of selectively moving the loopers beyond their normal operative range of movement to be readily available for servicing.
BACKGROUND OF THE INVENTION
In the majority of chainstitch sewing machines, one or more thread carrying loopers are employed to interloop their thread with the needle thread loop formed beneath the fabric. This action allows the thread to be concatenated into a stitch in the workpiece. In such machines, the looper is usually disposed in an area complicated by other mechanisms; i.e., feed mechanisms, throat plate, thread cutters, loop retainers, and etc. Therefore, operator access to the looper for purposes of servicing is extremely limited.
Mechanisms for retracting the looper to a threading position by bodily moving the looper are known in the art. Examples of this construction are illustrated in U.S. Pat. Nos. 1,912,959; 2,029,233; and, 3,354,851. With the ever increasing speeds of today's machines, however, it is been found necessary to compliment these mechanisms with additional features to prevent undesirable movement of the looper from its operative position while the machine is operating.
SUMMARY OF THE INVENTION
The present invention provides an improvement over the heretofore known looper throw out mechanisms by providing an improved arrangement for bodily moving the loopers to a servicable position and for locking the loopers in their operative position. To this end, the present invention includes a machine having a looper drive shaft and an operator influenced control assembly operatively secured to the shaft and effective to rotatably shift the looper means between operative and nonoperative positions. The assembly of the present invention includes looper carrier means arranged for pivotal movement on said shaft, a control disc adjustably fixed on said shaft and arranged in operative combination with a fork like member supported by the looper carrier means. The operative association of the control disc and the fork like member serves to prevent displacement of the looper carrier along the axis of the shaft. The control disc is provided with seperate locating surfaces defining operative and nonoperative positions of the looper means. The tines of the fork like member are adapted for alternative positive engagement against either of the locating surfaces for positioning the looper carrier and thereby the loopers. Operator controlled means are provided for selectively restraining the pivotal displacement of the carrier means relative to the shaft. Means are further provided for urging the looper means into their operative position.
In line with all of the above, it is a primary object of this invention to provide an improved looper throw out mechanism for chainstitch sewing machines.
Another object of this invention is the provision of suitable means which will facilitate the servicing of sewing machine loopers and reduce the time required for this operation.
Another object of this invention is to provide a looper throw out mechanism which may be simply operated at one end of the looper actuating shaft.
A further object of this invention is the provision of a looper throw out means which includes means for biasing the loopers into their normal operating position.
BRIEF DESCRIPTION OF THE DRAWINGS
Having in mind the above obJects and other attendent advantages that will be evident from an understanding of this disclosure, the invention comprises the devices combinations, and arrangement of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in detail to enable those skilled in the art to readily understand the functions, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic front view of a portion of a chainstitch sewing machine embodying the present invention;
FIG. 2 is a side fragmentary view of the sewing machine shown in FIG. 1;
FIG. 3 is a fragmentary front view illustrating the present invention with the sewing machine loopers disposed in their nonoperative position;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 1;
FIG. 5 is a perspective view of the looper throw out mechanism of the present invention; and
FIG. 6 is an enlarged sectional view taken along 6--6 of FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, wherein like reference numerals indicate like parts throughout the several views, in FIGS. 1 and 2 there is schematically illustrated a portion of a chainstitch sewing machine 10. The machine 10 includes a frame having a base portion or bed 12 provided with a work supporting surface 14 which may include the work supporting surface of a throat plate 15. The machine also includes one or more endwise reciprocatory needle means 16. Arranged in the bed beneath the sewing needles are an equal number of thread carrying looper means 18 which are adapted for cooperation with the needle means to conventionally form chainstitches in a workpiece being advanced through the sewing station of the machine. In the particular embodiment shown, the loopers are driven along an elliptical like path such that they simultaneously partake of oscillatory and rocking motions. That is, the looper motion includes movement endwise across the path of the needle's reciprocation to seize and shed needle thread loops and also an alternating sideways motion to avoid the needle means alternatively on opposite sides thereof. The four motion path which the loopers execute is well known in the sewing machine industry for sewing chainstitches (Federal Stitch Type 401).
In order to drive the loopers in the required elliptical motion and in timed relation to the reciprocation of the needles, a looper drive mechanism 20 is provided. As may be best described in connection with FIG. 2, the looper drive mechanism is operatively connected to a driven shaft 22 arranged in the machine bed 12. The looper actuating or drive mechanism may be similar to the type disclosed in U.S. Pat. No. 2,998,787 granted Sept. 5, 1981 to K. Pollmeier, the full disclosure of which is incorporated herein by reference. Suffice it to say, an output shaft 24 of the looper drive mechanism projects beyond the machine bed. The shaft may be journaled for oscillation and rotation along and about its longitudinal axis in a bore of a bushing 26 (FIG. 1) secured in the frame of the machine. Releasably clamped on the shaft 24 is a looper holder or carrier 28 which extends upwardly and carries at its upper end the loopers 18. Thus, the loopers partake of the motion of the shaft 24.
Thus far, what has been described is conventional. Because of the limited room beneath the work supporting surface of the machine, when it is desired or necessary to service the loopers, it is desirous to bodily move same beyond their normal operating position illustrated in FIG. 1 to a more convenient position as illustrated in FIG. 3. To this end, the present invention is provided.
In order to conveniently accomplish the above result, the present invention provides a looper throw out mechanism generally designated by reference numeral 30. The looper throw out mechanism of the present invention provides an operator controlled releasable connection between the loopers and their operating shaft. As best seen in FIGS. 1 and 5, the looper throw out mechanism includes a fork like member 32 and a control member or disc 34. The forked member 32 is secured by screw means 52 to and therefore rockable with the looper carrier means 28. The member 32 is provided with two spaced apart tines or arms 36 and 38 distantly arranged from the looper carrier and which are disposed on opposite sides of the rock shaft 24. Turning to FIG. 4, accomodated in the space between the arms 36 and 38 of member 32 and the looper carrier 28 is the control member or disc 34. Returning to FIGS. 1 and 5, the disc 34 is fixedly secured to the rock shaft 24 by means of a fastener 40 and cooperates with the member 32 in a manner whereby securing the looper carrier from lateral displacement along the longitudinal axis of the shaft 24. From one face of the plate like member 34 protrudes a block 42. As seen in the drawings, the spaced apart legs 36 and 38 of the fork like member 32 straddle the aforesaid block 42. The upper and lower surfaces 44 and 46, respectively, of the block 42 limit the angular or pivotal displacement of the looper carrier 28 with respect to the control disc 34. This end is accomplished by providing an alternative abutting relationship between the arms 36 and 38 of member 32 and the locating surfaces 44 and 46 of the control disc 34. That is, in one position, the looper means may be located in their operative position by positioning or locating the arm 36 of the fork like member 32 against the locating surface 44 of the control disc 34. When desired, the loopers may be moved to their nonoperative position, which is beyond the range of normal rocking movement, by rotating the looper carrier until the arm 38 of member 32 abuts against the other locating surface 46 of the control disc 34. In order to secure the looper carrier 28 in either of its adjustable positions, the looper throw out device includes a manually operable lever 50. As mentioned above, the looper carrier means 28 is pivotally carried on the rock shaft 24. As best seen in FIGS. 1, 3 and 6, at its lower most end, the looper carrier 28 is provided with a releasable split strap connection. The operative connection of the looper carrier to the shaft is accomplished by means of the bolt or fastener 52 which extends through a bore 54 (FIG. 6) provided in the carrier 28. The manually operable lever 50 is threadably engaged with one end of the bolt 52 to effect a clamping action thus positively securing the looper carrier to the shaft 24. To release the looper carrier 28 so that the loopers may be thrown or moved to a serviceable position, as illustrated in FIG. 3, the lever 50 is appropriately moved to unscrew internally threaded member 50a from bolt 52 to release the clamping relationship of the carrier 28 to the shaft 24 specifically as shown in FIG. 6, lever 50 is clamped to internally threaded member 50a which in turn cooperates with the external threads 52a of bolt 52 to exert a compressive action on carrier 28.
In the preferred embodiment, the looper carrier means 28 and thereby the looper means 18 are biased into their operative position by means of a spring biased detent assembly 66. The detent assembly is threadably arranged in a projection 68 provided on the member 32. The operative end of the detent assembly engages an appropriately inclined or concave surface 70 provided on the periphery of the control disc 34. The operative end of the detent assembly 66 engages the control disc 34 in a manner such that the arm 36 of the member 32 is continually urged against the locating surface 44 of the control disc 34 whereby locating the loopers in their operative position.
An exemplary operative procedure according to the invention will now be described. When it is necessary to service the loopers, the manually operable lever 50 is swung downward thus releasing the clamping relationship of the looper carrier means 28 with the rock shaft 24. The carrier may then be rotated in a clockwise direction (FIG. 1) such that the detent assembly 66 rides out of the concavity 70 to remove the loopers to their nonoperative position shown in FIG. 3. The extent of angular displacement of the looper carrier 28 being limited by the control disc 34. That is, the looper carrier 28 may be rotated clockwise (FIG. 1) until the arm 38 of the fork like member 32 abuts the locating surface 46 of the control disc 34. Because the control disc may be adjustably secured to the shaft, the disposition of the locating surfaces 44 and 46 and thus the operative and nonoperative positions of the loopers may be modulated as required. After the loopers have been serviced, the looper carrier is rotated in a counterclockwise direction (FIG. 1) whereby returning the loopers to their operative position. The counterclockwise rotation of the looper carrier continues until the arm 36 of the fork like member 32 again abuts the locating surface 44 of the control disc 34 thereby preventing further rotation of the looper carrier and thus positioning the loopers in their operative position. The spring detent assembly 66 action against the inclined peripheral surface 70 of the control disc 34 serves to maintain the loopers in their operative position while the manually operable means 50 is moved to clamp the looper carrier 28 to the shaft whereby setting the machine for continued operation. From the above, it will be apparent that a very simple means has been provided whereby the loopers are firmly held secured to the drive shaft by an operator manipulated device which quickly and easily releases the looper from the operative connection with the shaft and allows same to be moved to a nonoperative position.
Thus there has been provided a Sewing Machine Looper Throw Out Mechanism which fully satisfies the objects, aims, and advantages set forth above. While 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 in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.
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A looper throw out mechanism is provided for bodily moving sewing machine loopers from their normal operative position to a servicable position and back. The looper throw out mechanism includes a looper carrier pivotally arranged on the looper drive shaft, a fork like member attached to the looper carrier, a control disc disposed in operative combination with the fork like member for defining the angular displacement limits of the looper carrier, and a manually operated locking device for releasably securing the looper carrier to the looper drive shaft. When looper servicing is desired, the locking device is released by the operator permitting the looper carrier and the loopers to be pivoted to a serviceable position removed from their operative position.
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BACKGROUND OF THE INVENTION
I. Field of the Invention
This invention relates to directional microwave antenna systems and more particularly to a radar antenna system for use with an airborne radar. The antenna system comprises a parabolic dish reflector fed by a wave guide having two apertures and a splash plate positioned at the focus of the reflector. The antenna system produces a pencil beam which can be steered in azimuth and elevation by displacement of the parabolic reflector.
II. Description of the Prior Art
Directional microwave antenna systems such as that disclosed in U.S. Pat. No. 2,422,184 provide a pencil beam antenna pattern particularly adapted for use in airborne radar systems. These prior art systems comprise a parabolic reflector fed by a wave guide having apertures and a splash plate positioned at the focus of the reflector. The beams of these prior art antenna systems can be steered by movement of either the feed or the reflector or by pointing the entire antenna assembly. These systems are particularly useful in airborne systems where space is at a premium and where it is desirable to mount the radar antenna behind a radome.
Antenna systems used with airborne radars usually employ a relatively narrow beam to achieve high resolution. Because the magnetron transmitting tubes used with such radar systems are sensitive to reflected energy, the radar antenna system should reflect little energy, i.e. the voltage standing wave ratio (VSWR) of the antenna should be low. The side and back lobes of the radar antenna pattern must be maintained as low as possible, at least 20 db down, to avoid false target ambiguities.
The directional microwave antenna system disclosed in U.S. Pat. No. 2,422,184 to Cutler has, with some variations, been widely used in airborne radar antenna systems. This standard Cutler Cutler has a relatively high VSWR and thus reflects considerable energy back into the magnetron of the radar system. This reflected energy poses substantial design constraints because the radar system's automatic frequency control circuitry must be able to maintain lock with the desired signal in the presence of random-phase interfering reflected signals.
To overcome the reflected energy difficulties associated with the standard Cutler feed, it has been common practice to tune the antenna system by inserting tuning stubs in the wave guide of the antenna. The positioning of these tuning stubs is frequency sensitive and thus while the tuned Cutler feed system represents an improvement of the standard Cutler feed at a specific frequency, the system is very narrow-band. Further, there is a variation in the overall reflected power of the system as the parabolic reflector is moved from one position to another. This variation is exhibited by all Cutler feed antennas but is particularly pronounced for the stub-tuned Cutler feed.
SUMMARY OF THE INVENTION
The directive microwave antenna of the present invention incorporates impedance matching tabs in the feed mechanism of the antenna system which eliminates the high variations in reflected power exhibited by the standard Cutler antenna and the tuned Cutler antenna, thus providing an antenna system particularly adapted for use in airborne radar systems. Two configurations of the impedance matching tab are disclosed. A square impedance matching tab exhibits a VSWR of better than 1.22 to 1, excellent side-lobe performance with the beam dead ahead, but poor side-lobe performance with the beam off-axis. A circular tab exhibits a VSWR of better than 1.22 to 1 and has adequate side-lobe performance with the beam either dead ahead or up to 45° off-axis.
It is therefore an object of this invention to provide a directive microwave antenna system particularly suited for use in airborne radar applications.
It is another object of this invention to provide a directional microwave antenna system with a low voltage standing wave ratio.
It is another object of this invention to provide a directional mircowave antenna system whose side-lobe performance can be easily optimized for use with a scanning or fixed parabolic reflector.
It is another object of this invention to provide a directional microwave antenna system for use with a tuneable radar system.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features of this invention as well as the invention itself, both as to its method of organization and method of operation, will best be understood from the accompanying description, taken in connection with the accompanying drawings in which like reference characters refer to like parts, and in which:
FIG. 1 is a schematic illustration of the antenna system showing the parabolic reflector, the wave guide and splash plate.
FIG. 2 is a perspective illustration of the end of the wave guide with the splash plate attached.
FIG. 3 is an exploded view of the end of the wave guide showing the apertures and rectangular impedance matching tabs.
FIG. 4 is another exploded view of the end of the wave guide illustrating circular matching tabs.
FIG. 5 is a graphical representation of the Cutler feed with tuning stub showing the variation in VSWR as the frequency is varied from 9175 MHz to 9575 MHz.
FIG. 6 is a graphical representation of the standard Cutler feed showing the variation in VSWR as the frequency is varied from 9175 MHz to 9575 MHz.
FIG. 7 is a graphical representation of the Cutler feed with impedance matching tabs showing the variation in VSWR as the frequency is varied from 9175 MHz to 9575 MHz.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a side view of the radar antenna assembly 100 comprised of a parabolic reflector 110 a wave guide 120 a splash plate 130. The parabolic reflector 110 can be pivoted about pivot point 111 to scan the radar beam in elevation, and about pivot points 112 to scan the radar beam in azimuth.
Energy from the radar transmitter is coupled to the antenna and travels down wave guide 120 where it impinges upon radar splash plate 130 which directs the energy rearwards to the inner surface 113 of the parabolic reflector 110. Received energy reflecting from targets impinges upon parabolic reflector 110 and is focused back towards the splash plates 130 and thence along wave guide 130 to the radar receiver. Apertures 140 in wave guide 120 located in close proximity to radar splash plate 130 allow the energy to pass through the top and bottom of wave guide 120 as shown. These apertures are shown in detail in FIGS. 3 and 4.
FIG. 2 is a perspective view of the end of wave guide 120 with splash plate 130 attached.
FIG. 3 is a detailed view of the end of wave guide 120 showing two identical apertures 140 and matching tabs 141. The relative dimensions of the components of this system are a function of the frequency of the radar system. Typically, airborne radars operate at X-band centered at 9375 MHz. Rectangular wave guide for use at this frequency has interior dimensions of approximately 0.40 inches by 0.90 inches, shown as W and D respectively in FIG. 3. The rectangular matching tab of this invention is labeled bcde in FIG. 3. Identical tabs are used in each aperture, 140. Representative dimensions for this rectangular tab for use with an X-band radar are as follows:
bc = ed = 0.20 inch
cd = be = 0.50 inch
ha = gf = 0.40 inch
hg = af = 0.90 inch
The rectangular tab bcde is positioned along the centerline of side af of aperture hafg as shown.
FIG. 4 illustrates a circular version of the impedance matching tab of this invention. The radius of the circular tab R is greater than the perpendicular distance j that circular tabs 142 extend into apertures 140, so that the circular tab is less than a semicircle. The interior dimensions of wave guide 120 depicted in FIG. 4 are identical to the wave guide dimensions of the wave guide in FIG. 3, as are the dimensions of aperture hafg. Perpendicular distance j is 0.20.
Of course, the dimensions and relationships given above for the rectangular and circular tabs are representative but not exhaustive. The circular tab could be semicircular, or somewhat flatter than shown, and the lengths of side ab and ef of FIGS. 3 and 4 can be varied.
FIG. 6 illustrates the variation in VSWR of a standard Cutler feed as the frequency is varied from 9175 MHz to 9575 MHz. Three separate plots are given. The plot labeled "air" depicts the VSWR of the wave guide portion of the antenna system with no parabolic reflector installed. The other two plots illustrate the VSWR of the system with the reflector oriented on-axis (the orientation corresponding to the lowest VSWR), and off-axis at an orientation that produced the highest VSWR. The db numbers listed on the left side of the graph indicate the amount of attenuation of reflected power with respect to input power. For example, with the reflector at 10° and a frequency of 9375 MHz the reflected power will be 10 db below the input power. A db can be defined as follows: ##EQU1##
A representative input power for an airborne pulse radar system is 7 kilowatts. Under the conditions described above, reflected power would be 10 db down or would amount to 700 watts. FIG. 5 shows a similar relationship between the VSWR and frequency for a Culter feed with tuning stub. The tuning stub is quite frequency sensitive but does effectively reduce reflected power at the center frequency. However, the reflected power from the tuned Cutler antenna system varies substantially as the parabolic reflector is moved from 0° to 15° off-axis. At a frequency of 9375 MHz, the reflected energy is 13 db down with the reflector at 0° and more than 30 db down when the reflector is at 15°. Again, assuming an input power of 7 kilowatts, this amounts to a change in reflected power of 350 watts as the antenna scans. The phase of this reflected energy is random, accordingly this energy poses a significant constraint in the design of the automatic frequency control circuits of the radar.
FIG. 7 illustrates VSWR response of an antenna assembly employing the matching impedance tabs of the present invention (either rectangular or circular). As shown, the response of the impedance matching tabs is fairly broadband and achieves a low VSWR for all frequencies between 9175 MHz and 9575 MHz for reflector positions of 0° to 10°. At a frequency of 9375 MHz the reflected power is approximately 30 db down with the reflector at 0° and 19 db down with the reflector at 10°. This corresponds to a change in reflected power of 87.5 watts for a 7 kilowatt system, as the antenna scans. With the reflector on-axis, the VSWR is less than 1.12 to 1 over a frequency range of 4 percent of the design frequency of the antenna assembly--a significant improvement over prior art antenna assemblies.
The reflected power characteristics of the rectangular and circular matching tabs are essentially identical. However, there is one significant difference in the performance of the two configurations. The rectangular tab gives poor side lobe attenuation when the reflector is rotated off-axis to steer the beam, but good attenuation when the reflector is on-axis. The circular tab has adequate side-lobe attenuation for all typical reflector positions.
It is believed that the corners of the rectangular tab, points c and d of FIG. 3, act as independent radiators, thus the phase control fore and aft is excellent but off-axis phase control is poor. This off-axis multiphase wave creates cycles of side lobes as the parabolic reflector is moved to steer the beam.
In a typical system the reflector is moved through an arc of plus or minus 221/2° to steer the beam a total of plus or minus 45 degrees. In applications where it is not necessary to steer the beams through a significant arc, the rectangular tab provides a good VSWR over a broad band of frequencies.
For applications where it is necessary to steer the beam through a significant arc, it is preferable to use the circular impedance matching tab. This maintains a good VSWR while degrading the side lobe performance for the parabolic reflectors dead ahead but increasing the side lobe performance with the parabolic reflector off-axis.
A summary of the characteristics of the two configurations of impedance matching tabs is as follows:
______________________________________ SQUARE TAB CIRCULAR TAB______________________________________VSWR better than 1.22:1 better than 1.22:1______________________________________Side lobe per-formance with aparabolic reflector:Dead ahead excellent fairSide lobe per-formance with aparabolic reflector:Off axis poor fair______________________________________
It should be noted that, unlike prior art impedance matching devices used to tune antenna assemblies, the tabs of the present invention are easily fabricated since they are an integral part of the wave guide and can be machined when the wave guide is constructed. Accordingly, the tabs of the instant invention provide improved performance characteristics and yet are easily and economically fabricated.
In summary, the addition of impedance matching tabs to the wave guide apertures of a Cutler antenna provides improved VSWR over a fairly broad band. The choice of rectangular or circular configurations for the tab depends upon the desired side-lobe performance of the antenna system.
Although the invention has been described in detail above, the invention is not to be limited thereby, but only in accordance with the spirit and scope of the appended claims.
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A directional microwave antenna system comprising a concave reflector fed by a wave guide and splash plate assembly. Two rectangular apertures in the wave guide at the focus of the reflector admit energy to and from the splash plate. Impedance matching tabs protrude into the rectangular apertures to match the antenna system. Rectangular tabs provide improved VSWR, high side-lobe reduction with the reflector on-axis. Circular tabs provide improved VSWR and good side-lobe reduction with the reflector on or off axis.
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This invention relates to lever operated mechanisms for opening and closing a split metal clamp ring and more particularly to improvements in such lever operated mechanisms embodying means for locking the mechanism in ring closing position.
Due to their relative low cost, light weight and simplicity of structure, cylindrical containers or drums of fiber board or reinforced fiber glass are widely used for storing and shipping granulated materials, such as chemicals, detergents and like items. Containers of this type usually have a removable disk-like cover head adapted to interfit with a reinforcing rim about the open end of the container and a split clamping ring or band for holding the cover over the rim and open end of the container. Typically such a split clamping ring has a lever operated mechanism mounted between its ends for expanding or contracting the ring to facilitate connection and disconnection of the cover with the rim and open end of the container. In order to insure security of the closed container during shipment, it is highly desirable to provide some type of means for locking the split ring in its closed or clamped position to prevent unwanted removal or loss of the cover.
While there have been various developments of such locking devices and mechanisms in the past, the need still exists for an improved, simplified and dependably operable device for operating the clamping ring and positively securing the same in closed position.
In brief, the present invention contemplates an improved lever operated mechanism for contracting and expanding a split ring clamp characterized by an articulated linkage connection between the actuating lever and the ring ends and productive of a variable mechanical advantage increasing as the ring clamp approaches a closed position. A simplified locking means capable of moving laterally through an opening in the actuating lever is used for securing the latter positively to the clamp ring whereby to prevent unwanted ring opening movement.
It is a principal object of this invention to provide an improved lever operated mechanism for opening and closing a split clamp ring which incorporates means for locking the clamp ring in closed position.
It is another object of this invention to provide an improved clamp ring operating mechanism, as set out in the above object, which embodies articulated linkage means productive of a mechanical advantage which assists the user in closing the clamp ring.
It is another object of this invention to provide an improved lever operated mechanism for opening and closing a split clamp ring which employs a pivotally movable lever of the second class and latch means capable of securing the actuating lever against ring opening operation.
Still another important object of this invention is to provide an improved lever operated mechanism for opening and closing split clamp rings used with drum head covers and the like, which is economical to produce and dependable in its operational characteristics.
Having described this invention, the above and further objects, features and advantages thereof will appear from the following detailed description of a preferred and modified version thereof illustrated in the accompanying drawings and representing the best mode presently contemplated for enabling those of skill in this art to practice this invention.
IN THE DRAWINGS
FIG. 1 is a partial top plan view of a drum head cover and clamp ring equipped with an operating mechanism of this invention;
FIG. 2 is an elevational view of the assembly illustrated in FIG. 1;
FIG. 3 is a cross-sectional view taken substantially along vantage line 3--3 of FIG. 2 and looking in the direction of the arrows thereon;
FIG. 4 is a partial exploded perspective view of the clamp ring and operating mechanism set out in FIGS. 1 through 3;
FIG. 5 is a partial plan view, similar to FIG. 1, of a modified assembly employing a modified locking means for securing the operating mechanism against ring opening operation;
FIG. 6 is a front elevation of the modified assembly shown in FIG. 5;
FIG. 7 is a top plan view of the modified locking means embodied in the assembly of FIG. 5; and
FIG. 8 is a cross-sectional view taken substantially along vantage 8--8 of FIG. 6 and looking in the direction of the arrows thereon.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the particulars of the preferred embodiment, illustrative of this invention, attention is directed to FIGS. 1 through 4 of the drawings. As there shown, a conventional cylindrical storage drum 10 is provided with a removable cover 11 made of metal, plastic, fibre board, etc. which fits over a metal reinforcing rim 13 fitted about the open upper end of the drum. A split metal clamp ring 14 is used to secure the cover over the periphery of the reinforcing rim member in a conventional manner. The split ring 14 in turn is equipped with an improved lever operating mechanism 15 according to this invention for circumferentially expanding and retracting the ring 14 so as to release and lock the cover in position as the case may be.
As best shown in FIG. 4 of the drawings, mechanism 15 comprises an elongated operating lever 20 which is pivotally anchored at one end to an adjacent end of the split metal ring by means of a lever strap 21 and pivot or fulcrum pin 22. The operating lever 20 also is articulately connected to the other end of the locking ring 14 by means of an intervening linkage 23 which is pivotally joined to one end of a link strap 24 mounted on the clamp ring 14. Linkage 23 has sliding operational engagement with the lever 20 via a pair of elongated openings 25, 25 located intermediate the ends of the lever. A latch means 26 is provided to maintain the ring 14 in closed position. Thus, the mechanism 15 bridges the separable ends of the split metal clamp ring 14 and serves, as previously noted, to radially expand and contract ring 14 for purposes of releasing or clamping the cover 11 over the open upper end of the drum 10.
Operating lever 20 as best seen from FIG. 4, comprises a curvilinear backwall 30 flanked by right angularly related flange walls 31, 32 to formulate a generally U-shaped cross section (see FIG. 3). Each of the flange walls 31, 32 has a tapered plan configuration gradually decreasing from the leading end of the lever 20 toward the trailing or outer free end thereof. Flange wall 31 is also provided with an upstanding flange lip 33 curved to match the circumference of the drum and ring 14 whereby it abuttingly engages the outer face of the locking ring in the closed position of the operating lever. Flange wall 32, on the other hand, lies parallel to the flange wall 31 and preferably is of slightly greater lateral dimension throughout so as to extend beneath the locking ring 14 in the closed position of lever 20 as illustrated in FIG. 3. While this is a preferred construction of the lever, the same may take other forms and shapes including the elimination of the extension of the flange wall 32 beneath the locking ring as described.
Importantly each of the flange walls 31 and 32 has an elongated slotted opening 25 which is linear in formation and disposed intermediate the ends of the operating lever 20 although closer to the leading end thereof, which is pivotally joined to the locking ring, than to its opposite or free trailing end, as best shown in FIGS. 1 and 4. It will be recognized that the slotted openings 25, 25 in the two flange walls 31 and 32 are in superposed registration to provide a passageway through the operating lever 20. In addition to the structure of the operating lever as described, each of the flange walls 31 and 32 thereof has a terminal end portion comprising a mounting ear 35; the two mounting ears 35, 35 so provided lying in parallel spaced superposed opposition to one another with each having a central opening 36 receptive of the connective fulcrum pivot pin 22 therethrough. Further, the outer end of the lever 20 is adapted to receive one end of the lever strap 21 between the spaced ears 35, 35 for passage of the pin 22 therethrough; such pin being riveted over after passage through the ears 35, 35 and strap 21.
As best shown in FIG. 4 of the drawings, the lever strap 21 is formed as an elongated metal strap member having loop end portions 40, 41 formed at its opposite ends and a double wall portion 42 intermediate such loop portions. The medial portion 42 is provided with a pair of spaced openings 43, 43 receptive of a pair of rivets 44, 44 whereby the strap is secured to the outer face wall 45 of the locking ring adjacent its one end 46. Loop end portion 40 is disposed for coaxial alignment with and between the openings 36, 36 in the ear portions 35, 35, as above noted, so that pin 22 may pass through such loop 40 and ear portions for pivotally joining one end of the lever to one end of the lever strap 21. In this manner, the one inner end of the operating lever is joined to one end of the locking ring.
For purposes of providing connection between the operating lever 20 and the other end 48 of the locking ring 14, the articulated connecting link 23 is employed. This link comprises a closed, substantially rectangular shaped metal loop or bail having one end arm portion 50 which passes through the two opposed slotted openings 25, 25 in the operating lever (see FIG. 2) and an opposite end arm portion 51 which passes through a loop end portion 52 of the link strap 24; the latter being constructed essentially identical to the lever strap 21 except that only one end has a looped formation (see FIG. 4). The link strap 24 is, as best shown in FIG. 4, affixed adjacent the end portion 48 of the clamping ring by a pair of rivets 53, 53 which pass through strap 24 and the facewall 45 of the split ring 14.
From the description thus far, it will be recognized that the operating lever 20 constitutes a lever of the second class, fulcrumed about its one inner end which is adjoined to one end 46 of the clamp ring and is joined intermediate its ends, by the articulated linkage means 23, to the other end 48 of the clamping ring. This provides a sliding connection, via the elongated openings 25, between the operating lever and the articulated linkage means. With this arrangement, the linkage means 23 is slidably movable along the slotted openings 25 as the operating lever 20 is swung about its fulcrum formed by pin 22, thereby providing a multiple advantage lever arrangement in which the load transmitted to the lever via link 23 is translated to the operating lever at various positions along the slotted openings 25, i.e. at various positions medially of the length of the operating lever. Further, it will be noted that as the operating lever approaches a ring closing position, as illustrated in FIGS. 1 and 2 for example, the end arm portion 50 of the articulated link 23 approaches one end of the slotted openings 25, 25 nearest the fulcrum pin 22, thereby increasing the effective lever arm and mechanical advantage for the operating lever 20. Thus as the load increases on the operating lever its mechanical advantage likewise increases making it easier for the user to close the locking ring. In a similiar vein, maximum mechanical advantage is afforded to the operating lever during the ring opening operation particularly at the initiation of the ring opening operation to ease the burden of unclamping the ring 14.
In order to secure the clamping ring in its closed position as illustrated in FIGS. 1 and 2, and to avoid any unwanted or accidental release of the cover 11 from the drum, suitable latch means are provided for securing the operating lever against ring opening movement. To this end, the preferred form of latch means comprises the pivotally movable member 26, best illustrated in FIGS. 2 and 4 of the drawings. As there shown, the latch 26 is formed with a planar mounting portion 56 having an opening therethrough for reception of a fastening rivet 57 whereby such portion may be affixed to the outer wall 30 of the operating lever; opening 58 therethrough providing passage of rivet 57. Formed integrally with the upper end of the mounting portion 56 is a rearwardly extending angular wall portion 59 having a planar latching finger 60 depending from its rearward edge; finger 60 being provided with an opening 61 for reception of a shipping seal in a conventional manner (see FIG. 2). In order to secure the operating lever 20 in its ring closing position, it is necessary to swing the latch means 26 about its pivot center as provided by rivet means 57, whereby the depending finger portion 60 thereof enters the uppermost slotted opening 25, passes downwardly through the end loop portion 41 of the lever strap 21 and through the second slotted opening 25 formed in the bottom wall 32 of the lever. In this manner, the operating lever 20 is secured to the clamping ring via the looped end portion of the strap 21 and is thus positively restrained against ring opening operation until the latch means 26 is withdrawn from the loop portion 41. It will be recognized that the wall portion 59 provides means for gripping or prying the latch to unlock the lever 20.
While the foregoing description sets forth the features of what is considered to be the preferred form of this invention, as presently known, a modified version thereof is also illustrated in FIGS. 5 through 8 of the drawings, as will now be described.
As will be recognized from FIGS. 5 and 6, the lever operated mechanism indicated generally at 65, comprises an operating lever 66, joined to one end of the ring 14 by means of a lever strap 67 and a fulcrum connecting pin 68. An articulated link means 69 is pivotally joined to one looped end of a link strap 70, fixed to the other end of the clamping ring and is articulately joined to the operating lever via a pair of registeringly aligned slotted openings 71, 71, all as in the assembly 15 described hereinabove. It will be recognized that members 66 through 70 of assembly 65 are substantially identical to the corresponding members for the described assembly 15, with the exception of the lever strap member 67, as will now be described in detail.
As best shown in FIGS. 7 and 8, the modified strap member 67 is formed as a looped over metal strap having a single loop end portion 73 receptive of the fulcrum pin 68; the same being affixed to the locking ring 14 as by a pair of spaced rivets 74, 74 passing through a double thickness body portion 75 thereof. The opposite end of the strap member 67 is distinguished by a pair of outwardly extending separated arms 76, 76, each with a substantially right angular bend therein and each extending angularly from the plane of the body portion 75 thereof. Strap 67 is further distinguished from the strap 21 utilized in assembly 15, by virtue of its construction from spring metal, such as phosphor bronze or spring steel, whereby the extending arm portion 76, 76 at its one end are resiliently deformable toward and away from one another for engagement with lever 66 to provide an alternate latching means, as will now be described.
As will be understood from FIGS. 6 and 8 of the drawings, when the operating lever 66 is positioned in its ring closing position against the outer wall of the locking ring as illustrated, the resilient arm portions 76, 76 are disposed opposite and project into the two slotted openings 71, 71 formed through the lever flange walls. This serves to removably retain the operating lever in its ring closing position in accordance with that objective of this invention.
It is to be understood that the operating characteristics of the modified operating mechanism 65 are in general identical to that of assembly 15 hereinabove described in that the lever 66 is articulately joined to one end of the locking ring and pivotally joined to the other. The articulate linkage 69 and its connection with the elongated openings 71 of the lever constitute a multiposition interconnection therebetween whereby application of load to the second class lever is varied in accordance with the positioning of the link 69 along the slotted openings 71. As before, this arrangement provides an increasing mechanical advantage for the lever arm as the same approaches its ring closing position whereat the applied load is the greatest. Conversely, maximum lever advantage is immediately available to the operator for opening the ring. It also will be understood that as the lever 66 is brought to full ring closing position and engages the outer face of the locking ring, the resilient arm portions of 76, 76 of the latch means effectively secure the operating lever in its ring closing position by interengaging the slotted openings 71, 71.
From the foregoing it is believed those familiar with the art will readily recognize and appreciate the novel advancement of the improved lever operated mechanism hereinabove described over previous mechanisms for this purpose and will also understand that while the present invention has been described in association with preferred and modified embodiments thereof as set forth in the accompanying drawings, the same is susceptible to variation, modification and substitution of equivalents without departing from the scope of the invention as set forth in the following appended claims.
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A lever operated mechanism for opening and closing a split clamp ring used to secure a cover over the open end of cylindrical storage drums or barrels is disclosed in which the actuating lever is pivotally connected to one end of the ring and joined to the opposite end thereof by an intervening articulated link movable along an elongated opening extending laterally through the actuating lever to present a multi-position interlink between the ring ends productive of variable mechanical advantage which increases as the ring ends approach one another. The actuating lever also carries a pivotal latch adapted to move through the elongated opening therein for purposes of securing the actuating lever to the ring and thereby preventing ring opening operation of such lever. In a modified version deformable latch means move through the lever opening to hold the same against ring opening operation.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 687,590, filed May 19, 1976, now abandoned.
BACKGROUND OF THE INVENTION
Membrane oxygenators for blood are presently being sold by Travenol Laboratories, Inc., Deerfield, Ill., which contain a microporous, hydrophobic diffusion membrane. The diffusion membrane is pressed between membrane support members, and provided with a pair of flow paths, one for blood along one side of the membrane and another for oxygen and respired gases along the other side of the membrane.
The pores in the hydrophobic material are sufficiently small, compared with the thickness of the material, that blood cannot pass through the membrane. However, the pores provide improved permeability for gases through the membrane. Accordingly, oxygen, carbon dioxide, and water vapor are rapidly exchanged through the membrane. See U.S. Pat. Nos. 3,757,955 and 3,927,980 for descriptions of the construction and use of oxygenators having hydrophobic membranes.
Such oxygenators for blood made of porous, hydrophobic membrane have turned out to be a major step forward in the field of blood oxygenation, and are being used in open heart surgery and other medical procedures with significantly improved success over that which has gone before in the prior art. The devices of this invention exhibit excellent blood compatibility, permitting relatively long-term use, coupled with a high level of blood oxygenation.
However, it has been considered desirable by some experts to use hydrophilic, blood-contacting membranes rather than hydrophobic membranes, for the reason that there is increased compatibility between hydrophilic membranes and the formed elements of the blood, as well as plasma portions, when compared with hydrophobic membranes.
However, hydrophilic membranes may not be rendered porous without causing leakage of aqueous liquids across the membrane, and hydrophilic membranes generally exhibit far less capacity for oxygen and carbon dioxide transfer.
In accordance with this invention, a hydrophobic membrane, preferably a porous, hydrophobic membrane, is provided with a hydrophilic outer surface. Accordingly, the resulting membrane can exhibit the desirable transfer characteristics of hydrophobic membranes, specifically the porous membranes, while at the same time presenting a hydrophilic surface to the blood, resulting in less platelet attachment and the like.
Also, the membranes of this invention, and especially the porous membranes, can be used to process other aqueous liquids in the medical as well as other fields, as well as nonaqueous liquids having surface tensions similar to water, without leakage.
DESCRIPTION OF THE INVENTION
A diffusion device, typically for blood, may be assembled by overlaying membrane support means with a diffusion membrane comprising hydrophobic material, to form a diffusion device defining a first flow path for one fluid along one side of the diffusion membrane, and a second flow path for another fluid along the other side of said diffusion membrane. In accordance with this invention, prior to the overlaying of the support means by the membrane, one surface, typically the blood-contacting surface, of the diffusion membrane is subjected to ionizing atmosphere conditions, so as to increase the surface tension of the membrane surface to render it more hydrophilic.
Typically, the ionizing conditions utilized herein are created by subjecting the membrane to a corona discharge in air. Corona discharge treatment of polyethylene film for other purposes is a well-known and conventional process. Apparatus for subjecting films to a corona discharge is sold by the Pillar Corporation, 7000 West Walker Street, Milwaukee, Wis.
While the specific corona discharge conditions may vary in accordance with the nature of the diffusion membrane to be treated and other conditions, successful results have been obtained with a Pillar Solid State Corona Treater by generating a corona discharge field with 2,000 volt, 4 Kilohertz alternating current, and passing the membrane material through the field. Porous, hydrophobic membranes having a pore size of no more than 5 microns, made of aliphatic hydrocarbons, are generally preferred. Conveniently, both sides of the membrane may be rendered hydrophilic, if desired.
A specific membrane material subjected to the corona discharge field may be a polypropylene membrane having a thickness of 0.001 inch, and an effective pore size of 0.1 micron (Cellgard 2400, manufactured by the Celanese Corporation). By this processing technique, the polypropylene material described above, which normally has a surface tension of about 34 dynes/cm. can be changed to a material having a surface tension of about 60 dynes/cm. However, it may only be necessary to treat the surface only to an extent that the surface becomes wettable to the fluid which it will contact, i.e., the surface tension of the membrane may be raised only to just barely greater than that of the fluid, at the temperature and other conditions of the intended use.
Typically, the process of this invention will be performed in the air, since the presence of oxygen appears to facilitate the process. Accordingly, it is generally preferred that the process be performed in essentially ambient pressures, and in an atmosphere having at least 10 percent oxygen. However, some increase in the surface tension is noted when the diffusion membrane is subjected to corona discharge in, for example, a pure nitrogen atmosphere.
While it is generally preferred to utilize diffusion membranes made of aliphatic hydrocarbon polymers, such as polyethylene and polypropylene, it is contemplated that other membranes may also be altered in their surface tension, such as silicone rubber film and polytetrafluoroethylene films. Also, copolymers of hydrocarbons such as ethylene and propylene, copolymerized with other units such as styrene (for stiffening the membranes), butadiene, and the like may be utilized if desired.
The corona treatment process can be performed on a continuous basis, where each portion of the membrane is exposed to the corona field for only a fraction of a second, if desired, in accordance with the recommendation of the manufacturer of the particular corona discharge unit utilized. It is generally thought that for any particular membrane it may be possible to overtreat the membrane, so that the inner surfaces of the pores of the membrane are also rendered hydrophilic, resulting in an increased capability of the porous membranes to permit fluids from blood and the like to pass through the membrane. This is usually undesirable, and may be avoided by simply reducing the length of exposure of the membrane to the corona discharge field, or the intensity of the field.
It is generally preferable to treat membranes in accordance with this invention to cause their surface tension to increase to at least 50 dynes/cm., to obtain a significant increase in the hydrophilic characteristics of the membrane.
It is also contemplated that other ionizing conditions may be used as well as corona discharge; for example oxygen ions and other ions may be generated by an electric arc in the vicinity of the membrane to be treated, or the membrane may be exposed to various forms of ionizing radiation.
The drawing illustrates a schematic diagram of a method in accordance with this invention for the manufacture of oxygenators for blood.
Referring to the drawing, a roll 10 of porous, hydrophobic membrane 11 is provided, for example the porous polypropylene material described above. The roll of membrane material is unrolled to pass through a corona discharge device 12, which comprises a pair of electrodes 14, 16 with their facing surfaces being covered with an insulating material such as silicone resin or rubber, to create the corona field.
The air in the space between electrodes 14, 16 ionizes during operation. A transformation of the surface of membrane 11 takes place, causing the normal surface tension for the polypropylene material used of about 35 dynes/cm. to increase to about 60 dynes/cm., imparting hydrophilic characteristics to the membrane surface.
Thereafter, the treated membrane passes to a cutting station 20, in which the membrane strip is cut into desired lengths of membrane 22. The lengths of membrane 22 are then laid over and against a membrane support sheet 24, which has been prescored and prefolded along fold lines 26 to form a plurality of sections 28. The specific details of the exact structure of the device being made may be as described in U.S. Pat. No. 3,757,955.
Thereafter, membrane 22 and membrane support 24 may be folded together into a convoluted, pleated structure 30 to form a diffusion stack defining a series of flow channels 32 on one side of the stack for the passage of oxygen gas, and another series of flow channels 34 on the other side of membrane 22 for the passage of blood, as described in the U.S. patent mentioned above. Additional membrane support structures 36 may be added to the blood flow paths as desired.
The entire stack 30 is then inserted in a suitable container, having manifold ports for the inlet and outlet of gas and blood. The container is sealed, and the device is sterilized in suitable manner for use.
While the method of this invention finds particular utility in diffusion devices for blood, it is also contemplated that other types of diffusion devices may also be made in accordance with this invention.
The above has been offered for illustrative purposes only, and is not for the purpose of limiting the invention of this application, which is as defined in the claims below.
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Hydrophobic diffusion membranes such as porous polypropylene may be rendered hydrophilic at their surfaces, without losing their valuable characteristics as diffusion membranes, by subjection to a corona discharge or other ionizing condition, preferably in air or a similar oxygen-containing atmosphere.
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[0001] This application claims priority to U.S. Provisional Patent Application No. 61/356,325 file on Jun. 18, 2010.
BACKGROUND OF THE INVENTION
[0002] The present invention is related to an electronic stroke monitor for a vehicle brake. More specifically, the present invention is related to an electronic stroke monitor of an air disc brake for use on a heavy duty truck.
[0003] The number of miles traveled by heavy-duty trucks and passenger busses increases significantly every year. Because the size of passenger cars being driven has become smaller due to the increased price of gasoline, it has become increasingly necessary to ensure the proper performance of brake actuators and brake systems of these heavy-duty vehicles to provide the truck operator every opportunity to avoid a loss of control. Therefore, various systems have been developed to monitor the stroke of a brake actuator for use on drum brakes widely used in industrial trucking.
[0004] However, on heavy-duty passenger vehicles, such as, for example, busses, the use of air disc brakes is becoming more popular. To date, a viable brake monitoring system for use on an air disk brake has not been developed.
[0005] Brake monitoring systems used on air drum brakes are directed toward monitoring the length of stroke of a pushrod projecting from inside a chamber of the brake actuator. The monitoring enables the user to determine if the brake actuator is functioning properly, is subject to an over-stroke condition, or is subject to a hanging or dragging brake condition. Monitoring these conditions by monitoring the stroke of the pushrod is possible because the pushrod of the brake actuator is fixedly attached to the actuation device of the drum brake. In the case of a hanging or dragging brake, the actuation device of the drum brake is immobilized in an actuated position preventing the pushrod from returning to an un-actuated position when the brake pedal is released by the vehicle operator.
[0006] However, the pushrod of an air disk brake actuator is not fixedly attached to the lever arm of a caliper that actuates the disk brake. Therefore, should a hanging or dragging brake condition occur, the lever arm becomes separated from the pushrod rendering the type of monitoring system used on a drum brake non-functional for a disk brake. An electronic sensor that monitors the stroke of the pushrod senses that the pushrod has returned to its un-actuated position and incorrectly senses that the brake is operating normally. Therefore, it has become necessary to develop a vehicle brake monitoring assembly that is capable of identifying and distinguishing between an over-stroke condition and a hanging brake condition of an air disk brake.
SUMMARY OF THE INVENTION
[0007] A vehicle brake monitor assembly for an air disk brake includes a brake actuator having a pushrod projecting from inside a chamber of the brake actuator. The pushrod releasably actuates a lever arm of the caliper moving the disk brake into braking position when the pushrod is disposed in an extended position and releases the disk brake from the braking position when the pushrod is disposed in a retracted position. The pushrod includes a pushrod shaft and a contact member biased in a telescoping relationship relative to the pushrod shaft. The lever arm of the caliper abuts the contact member and counteracts the bias of the contact member preventing the contact member from telescoping from the pushrod shaft. A sensor is integrated with the assembly proximate the contact member. The sensor detects movement of the pushrod relative to the lever arm and the pushrod shaft.
[0008] The sensor that is positioned proximate the contact member detects differences in transmission along a length of the contact member that enables the determination of the condition of the brake actuator. For example, the sensor detects when the brake is operating in a normal condition, is subject to a dragging brake condition, is subject to an over stroke condition, or subject to an out of adjustment condition. As set forth above, prior attempts to monitor all these conditions on an air disk brake have proven futile. In particular, prior monitoring devices have been unable to identify a hanging brake condition due to separation between the pushrod and a lever arm of the air disk brake. This separation results when the lever arm is immobilized in an actuated position and a vehicle operator releases a brake pedal causing the pushrod to retract into the brake actuator. The telescoping design of the present invention allows the sensor to detect when the lever arm is immobilized in an actuated position.
[0009] A further benefit of the present inventive assembly is its use with a conventional brake caliper without modification to the caliper. Prior attempts to monitor air disk brake systems require modifying the brake caliper in an attempt to determine if the lever arm is immobilized in an actuated position. By providing a sensor pack proximate the pushrod of the actuator, the inventive assembly has eliminated the need to modify the caliper of an air disk brake system, to detect a dragging brake condition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
[0011] FIG. 1 shows a side sectional view of the brake monitoring assembly of the present invention;
[0012] FIG. 2 a shows a first embodiment of the pushrod of the present invention;
[0013] FIG. 2 b shows an alternative embodiment of the pushrod of the present invention;
[0014] FIG. 3 shows an expanded view of the pushrod of the present invention;
[0015] FIG. 4 shows the brake actuator in an extended position in a normal operating condition;
[0016] FIG. 5 shows a partial sectional view of the brake actuator in an over stroke condition; and
[0017] FIG. 6 shows the brake actuator of the present invention having a hanging or dragging brake condition.
DETAILED DESCRIPTION OF THE INVENTION
[0018] A brake actuator is shown generally at 10 in FIG. 1 . The brake actuator 10 includes a brake monitor assembly 12 for determining if the brake actuator is functioning in a normal condition or a fault condition as will be explained further hereinbelow. The brake actuator 10 includes a pushrod 14 disposed inside a service chamber 16 . It should be understood by those skilled in the art that the service chamber 16 can also be used in cooperation with a secondary chamber or power spring chamber (not shown), and various other brake activator configurations, as might be necessary for a given vehicle braking system.
[0019] The service chamber 16 includes a diaphragm 18 that is secured between an upper housing member 20 and a lower housing member 22 . Therefore, the service chamber 16 is separated by the diaphragm 18 into a pressure side 24 (best seen in FIG. 4 ) and a return side 26 which houses a return spring 28 . Pressurized air enters the pressure side 24 of the service chamber 16 through air pressure port 30 , the pressure of which is monitored by pressure sensor 32 . Although the pressure sensor 32 is shown proximate the service chamber 16 , it is contemplated by the inventors that the pressure sensor 32 is located at the treadle valve (brake pedal) of the vehicle. It should be understood to those of ordinary skill in the art that each embodiment also includes a separate pressure sensor (not shown) located at the brake pedal to identify pressure being applied by the vehicle operator to the brake pedal. When the operator actuates the brake pedal, pressurized air passes through the air pressure port 30 forcing the diaphragm 18 against the pushrod 14 causing the pushrod 14 to extend outwardly from the service chamber 16 in a known manner.
[0020] When the vehicle operator depresses the brake pedal, as set forth above, air pressure enters the pressure side 24 of the service chamber 16 through the air pressure port 30 forcing the pushrod 14 outwardly from the service chamber. A lever arm 34 disposed inside a caliper 36 is pivoted by the pushrod 14 , when extending outwardly, causing the brakes (not shown) of the vehicle to actuate in a known manner. When the vehicle operator removes pressure from the brake pad, air is vented from the pressure side 24 of the service chamber 16 and the return spring 28 forces the pushrod 14 inwardly of the service chamber 16 allowing the lever arm 34 to return to its unactuated position. It should be understood by those of skill in the art, that the caliper 36 described above functions in a normal manner.
[0021] Referring now to FIG. 2A , the pushrod 14 includes a contact member 38 that circumscribes a pushrod shaft 40 . The contact member 38 defines a terminal end 41 that abuts the lever arm 34 of the caliper 36 . The pushrod shaft 40 is received in a tubular opening 42 defined by the contact member 38 . An adjustment shim 44 is disposed at a base 46 of the tubular opening 42 and is sandwiched between a shaft stop 48 of the pushrod shaft 40 and the base 46 . The adjustment shim 44 is provided in a plurality of thicknesses from which the length of the pushrod 14 is adjusted to provide dimensional accuracy between terminal end 41 of contact member 38 and lever arm 34 as will become more evident below.
[0022] The pushrod shaft 40 defines an elongated opening 50 , which receives a biasing member 52 shown here in the form of a spring. The biasing member 52 is compressed between a floor 53 and a terminal wall 54 of the elongated opening 50 . Therefore, the biasing member 52 provides a biasing force that telescopes the contact member 38 from the pushrod shaft 40 , affectively lengthening the pushrod 14 .
[0023] The pushrod shaft 40 defines a circumscribing groove 56 into which a retaining member 58 that is fixedly attached to an inner wall 60 of the tubular member 42 is received. The retaining member 58 slides in an axial direction defined by the pushrod shaft 40 within an expanse of the groove 56 . A stop 62 prevents the biasing member 52 from separating the contact member 38 from the pushrod shaft 40 when abutted by the retaining member 58 . The stop 62 takes the form of a spring clip or equivalent received by a notch 63 ( FIG. 3 ) in the pushrod shaft 40 .
[0024] A sensor element 64 is sandwiched between the service chamber 16 and the caliper 36 . A sensor 66 is disposed inside the sensor element 64 and is provided sensing access to the contact member 38 , which is received through an opening 68 in the sensor element 64 . The sensor 66 communicates through communication line 70 with a controller or central processing unit 72 . The sensor 66 is contemplated by the inventors to take the form an optical sensor, a magnetic sensor, a mechanical sensor, or a radio frequency enhanced sensor. For clarity, however, the following description will describe an optical sensor, further contemplated to be an infrared sensor. The exemplary embodiment makes use of an Optek infrared optical OPB733TR sensor capable of both transmitting an infrared signal and receiving a reflected infrared input. However, it should be understood by those of skill in the art, that any of the sensors explained above are operable. As best represented in FIG. 2 a , the contact member 38 defines a non-reflective surface 74 , a semi-reflective surface 76 , and a fully reflective surface 78 .
[0025] As best seen in FIG. 1 , a sealing boot 80 seals to the pushrod shaft 40 at an upper end and to the sensor element 64 at an opposite end. Therefore, the contact member 38 , and the non-reflective, semi-reflective, and fully reflective surfaces 74 , 76 , 78 are protected from environmental contamination that is known to enter the service chamber 16 . A secondary seal 82 seals the sensor element 64 to the caliper 36 , which is fully enclosed to protect the lever arm 34 from environmental contamination. Therefore, the contact member 38 and the sensor 66 are completely protected from the environment, preventing the optical sensor 66 and the reflective surfaces 74 , 76 , 78 from becoming fouled.
[0026] An alternative embodiment is shown in FIG. 2 b where common elements have the same numbers as those elements disclosed in FIG. 2 a . The alternative embodiment makes use of an alternative contact member 84 and a linear sensor 86 . The alternative contact member 84 includes an alternative reflective coating 88 that has a variable reflective surface. A first end 90 of the contact member is more reflective than a second end 92 of the contact member with a gradual transition in between. The sensor detects the variation in the amount of reflectivity to determine the location of the alternative contact member 84 , and therefore the lever arm 34 as will become more evident in the description below.
[0027] The sequence of brake monitoring will now be described. It is contemplated by the inventors that the sensor 66 takes the form of an infrared sensor that transmits an infrared signal toward the contact member 38 which has varying degrees of reflectivity as described above to reflect the infrared signal back toward the sensor 66 , which in turn signals the controller 72 the degree of reflectivity via communication lines 70 . It should be understood to those of skill in the art that other optical sensors may be used, including photoelectric digital lasers, ordinary lasers, and equivalents.
[0028] During normal operation, when the brake is released (shown in FIG. 1 ), the optical sensor transmits a light signal toward the non-reflective surface 74 of the contact member 38 receiving no reflective signal from the contact member 38 . The brake application pressure, as indicated by the pressure sensor 32 , is less than or equal to about 2 psi. Therefore, no active fault is signaled to the vehicle operator.
[0029] Referring now to FIG. 4 , pressure is applied to the brake pedal by the operator causing air to fill the pressure side 24 of the service chamber 16 to actuate the lever arm 34 . Because the pushrod 14 is forced outwardly from the service chamber 16 by the diaphragm 18 , the sensor 66 is positioned proximate the semi-reflective surface 76 of the contact member 38 . The pressure sensor 32 signals air pressure of greater than or equal to about 2 psi indicating normal operation of the brake actuator 10 so long as the sensor 66 detects reflectivity from the semi-reflective surface 76 . It is contemplated by the inventors that the semi-reflective surface 76 reflects about thirty percent of the light transmitted from the sensor 66 . It should be noted that the biasing member 52 remains fully compressed because the lever arm 34 counteracts the biasing force of the biasing member 52 during normal, activated condition.
[0030] FIG. 5 shows an overstroke condition causing the controller 72 to signal the operator that a fault condition exists. In the overstroke condition, the pushrod 14 extends outwardly of the service chamber 16 beyond normal extension length so that the sensor 66 transmits light to the fully reflective surface 78 and detects a full reflectivity. The brake pressure, as detected by the pressure sensor 32 , is greater than or equal to about 2 psi. Therefore, the sensor 66 signals the controller 72 full reflectivity with normal application pressure causing the controller to signal an over stroke condition to the operator.
[0031] FIG. 6 represents a dragging brake condition. The dragging brake condition is identified by the controller 72 both when the vehicle is moving at road speed and when the vehicle is not moving at road speed. In the dragging brake condition, air pressure has been released from the pressure side 24 of the service chamber 16 causing the return spring 28 to retract the pushrod 14 into the service chamber 16 . However, because the brake is now subject to a dragging condition, the lever arm 34 is retained in the actuated position causing separation with the contact member 38 . Because the lever arm 34 is no longer counteracting the biasing force of the biasing member, the biasing member 52 causes the contact member 38 to telescope from the pushrod shaft 40 . Therefore, the sensor 66 now transmits light toward the semi-reflective surface 76 of the contact member 38 as opposed to transmitting light toward the non-reflective surface 74 as is typical of a normally functioning brake. Because the pressurized air has been vented from the pressure side 24 of the service chamber 16 , the brake application pressure now reads less than or equal to about 2 psi. The combination of the semi-reflective surface 76 being detected by the sensor 66 and the low air pressure of less than or equal to about 2 psi causes the controller 72 to indicate a dragging or hanging brake condition.
[0032] A further fault condition is indicated when the sensor 66 detects the non-reflective surface 74 when the brake pedal is depressed by the operator causing an air pressure reading of greater than or equal to about 12 psi. In this instance, the controller signals a non-functioning actuator condition to the operator.
[0033] The invention has been described in an illustrative manner, and 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.
[0034] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, a hall effect or equivalent sensor can be used in combination with a magnet affixed to the contact member 38 having varying degrees of magnetism. It is therefore to be understood that within the specification, the reference numerals are merely for convenience, and are not to be in any way limiting, the invention may be practiced otherwise than is specifically described.
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A vehicle brake monitor assembly for an air disk brake includes a brake actuator having a pushrod projecting from inside a chamber of said brake actuator. The pushrod releasably actuates a lever arm of a caliper thereby moving the disk brake into a braking position when the pushrod is in an extended position and releasing the disk brake from the braking position when the pushrod is in a retracted position. The pushrod includes a pushrod shaft and a contact member biased in a telescoping relationship relative to the pushrod shaft and the lever arm of the caliper abuts the contact member counteracting the bias of the contact member. A sensor is integrated with the assembly proximate the contact member and detects movement of the pushrod relative to the lever arm and to the pushrod shaft.
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FIELD OF THE INVENTION
[0001] This invention generally relates to refrigerant systems. More particularly, this invention relates to controlling pressure within an air conditioning or refrigeration system during storage or transportation.
DESCRIPTION OF THE RELATED ART
[0002] Air conditioning systems typically utilize a refrigerant to achieve a desired amount of cooling within a building, for example. Systems typically are charged at a factory with an amount of refrigerant to provide adequate system performance for expected operating conditions.
[0003] The refrigerant system can be divided into low and high pressure sides. The low pressure side is the system side that is exposed to lower, suction pressure during operation. The high pressure side is the system side that is exposed to higher, discharge pressure during operation. During operation the discharge pressure is normally several times higher than suction pressure. However, when the system is shutdown, both suction and discharge pressure equal each other soon after shutdown.
[0004] The low pressure side of the system reaches the highest pressure during system transportation or storage. The pressure in the low pressure side during transportation or storage can be several times higher than the maximum pressure the low side of the system experiences during normal system operation. The system components typically must be designed with a safety margin sufficient to withstand such pressure. The associated increases in component strength cause increased component cost and weight.
[0005] With the introduction of higher pressure refrigerants, such as R410A, the above concerns are increased. Additionally, certain governing bodies are introducing new, more stringent high pressure strength requirements. It is desirable to provide a cost-effective way to deal with this situation.
[0006] This invention provides a way to manage the pressure within the refrigerant system during transportation or storage that avoids the shortcomings and drawbacks described above.
SUMMARY OF THE INVENTION
[0007] In general terms, this invention is a unique way of managing the pressure within a refrigerant system during transportation or storage.
[0008] One example system designed according to an embodiment of this invention includes a refrigerant receptacle and a pressure relief device that couples the receptacle to the system. The pressure relief device operates responsive to a pressure in the system that exceeds a selected threshold. Accordingly, refrigerant from the system can flow into the refrigerant receptacle whenever the pressure in the system exceeds the threshold.
[0009] In one example, the pressure relief device includes a valve that will automatically open responsive to an undesirably high pressure in the system and release the refrigerant into the receptacle. The receptacle provides additional volume within which the refrigerant can be contained, which reduces the pressure in the system. This approach avoids the necessity of over-designing the air conditioning system low pressure side components, such as a compressor and an evaporator, and, therefore, provides an associated cost savings. Various shutoff and recovery valves and devices can be added to the receptacle for convenience, as well.
[0010] The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 schematically illustrates a refrigerant system including a refrigerant receptacle for managing a pressure within the system during transportation or storage, for example.
[0012] FIG. 2 schematically illustrates another example arrangement of a system designed according to this invention.
[0013] FIG. 3 schematically illustrates another example arrangement of a system designed according to this invention.
[0014] FIG. 4 schematically illustrates another example arrangement of a system designed according to this invention.
[0015] FIG. 5 schematically illustrates another example arrangement of a system designed according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] FIG. 1 schematically shows a refrigerant system 20 that may be used as a refrigeration system, a heat pump or an air conditioning system. In a cooling mode, a compressor 22 draws refrigerant from a suction port 24 and provides a compressed gas under pressure to a compressor discharge port 26 . The high temperature, pressurized gas flows through a conduit 28 to a condenser 30 where the gas dissipates heat and condenses into a liquid as known. The liquid refrigerant flows through a conduit 32 to an expansion device 34 . In one example, the expansion device 34 is a valve that operates in a known manner to allow the liquid refrigerant to expand and to partially evaporate and flow into a conduit 36 in the form of a cold, low pressure refrigerant. This refrigerant then flows through an evaporator 38 where the refrigerant absorbs heat from air that flows across the evaporator coils, which provides cooled air to the air conditioned space as known. The refrigerant exiting the evaporator 38 flows through a conduit 40 to the suction port 24 of the compressor 22 where the cycle continues. As known, during a heating mode, the refrigerant flows are reversed.
[0017] The system 20 has a high pressure side, in which the components are exposed to discharge pressure, between the discharge section of the compressor 22 and the entrance to the expansion device 34 . A low pressure side, in which the components are exposed to suction pressures, exists between the exit from the expansion device 34 and the suction section of the compressor 22 .
[0018] The illustrated example includes an external refrigerant receptacle 50 that is coupled to the system for selective fluid communication. In this example, a pressure relief device 52 selectively allows refrigerant to flow from the system into the receptacle 50 whenever the pressure in the system exceeds a selected threshold. By coupling the receptacle 50 to the system, the example arrangement effectively increases the volume within which the refrigerant can be contained, which reduces the pressure. Accordingly, whenever the pressure in the system exceeds a selected threshold for the low pressure side, adding the volume of the external receptacle 50 to the system volume allows the pressure in the system to be brought back down to an acceptable level.
[0019] In one example, the threshold is dictated by the chosen refrigerant, system component strength on the system low pressure side or the limits set by an appropriate regulatory or governing body. Those skilled in the art who have the benefit of this description will be able to select an appropriate threshold to suit their particular situation.
[0020] In another example as shown in FIG. 2 , an optional valve 54 is provided. The flow control valve 54 is a shut-off valve that allows for selectively isolating the receptacle 50 from the relief device 52 , which in this example is a rupture disk, or the system. In this example, the valve 54 is utilized in case the receptacle 50 is removed from the system and needs to be installed once again in other units for same purpose during transportation or storage. It also can be used if the rupture disk 52 was ruptured due to pressure in the system 20 exceeding the allowable pressure threshold and just the receptacle needs to be removed to be reused, for example.
[0021] Another example designed according to the embodiment of FIG. 2 has a flow control valve 54 that operates as a check valve to allow flow of refrigerant in only one direction from the system to the receptacle 50 .
[0022] In another example shown in FIG. 3 , an optional valve 56 is provided to selectively isolate the rupture disk 52 along with the receptacle 50 from the rest of the system 20 for recycling or any other purpose. Although the receptacle 50 and the rupture disk 52 are shown associated with the conduit 40 , a connection to any appropriate part of the system is within the scope of this invention.
[0023] FIG. 4 illustrates another example embodiment that includes both optional valves 54 and 56 .
[0024] The example of FIG. 5 includes an optional access valve 58 that allows for reclaiming refrigerant from the receptacle 50 or initially pressurizing the receptacle 50 with a selected amount of refrigerant to a specified pressure.
[0025] The receptacle 50 may be at vacuum or contain a small amount of refrigerant during system assembly and charging with the refrigerant, at a factory, for example. Any refrigerant within the receptacle 50 preferably is kept at a pressure well below the pressure of the non-operating system to maximize the amount of refrigerant that can flow into the receptacle 50 in the event that the pressure in the system exceeds the selected threshold.
[0026] When refrigerant is released into receptacle 50 , preferably there is a visible indication of when the refrigerant release has occurred. This allows a technician to have a visual confirmation that refrigerant was released into the receptacle 50 . If that did occur, a technician can add charge to the system to account for any refrigerant that was transferred into the receptacle during shipping or storage. In most probable scenario, the pressure relief device will not have been activated and the technician can proceed with system installation as normal.
[0027] In some of the illustrated examples, the external receptacle 50 may be selectively removed from the system once the system is installed at the selected site so that the receptacle can be reused with another system that will be charged in a factory. Alternatively, if the receptacle 50 is connected to low pressure side of the system, it may be left in place and the pressure relief device 52 set for activation in the unlikely event that the low pressure side becomes over-pressurized during system operation.
[0028] The illustrated examples provide cost effective ways to handle low side system over-pressure during shipment or storage to prevent overpressurisation above an established, acceptable limit.
[0029] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.
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An air conditioning or refrigeration system includes an attached refrigerant receptacle associated with the system. During shipment or storage, the pressure within the system may exceed a selected threshold for the low pressure side. Under such circumstances, a pressure relief device automatically allows refrigerant to flow from the system into the attached receptacle, which brings the pressure within the system back to an acceptable level for the low pressure side. Various optional shutoff devices are disclosed that can be incorporated into the design to simplify receptacle removal or recycling.
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The present application claims priority from U.S. Provisional Application No. 61/254,544 filed Oct. 23, 2009, the entire disclosure of which is incorporated herein by reference.
BACKGROUND
Within the semiconductor industry, there exists the need to improve yield, throughput, and the ever present quest to maintain pace with Moore's Law. The ideal way of accomplishing a process characterization is to provide a mechanism for real-time data collection of vital process parameters—explicitly the mechanical and electrical forces seen by the substrate.
FIG. 1 illustrates a portion of a conventional linear wet chemical cleaning system 100 .
As illustrated in FIG. 1 , cleaning system 100 includes a holding tray 102 , a carrier tray 104 , a powered rail 112 , attachment devices 110 , 114 , 126 and 130 , a non-powered rail 128 and a cleaning portion 118 . Cleaning portion 118 includes a plurality of process shower heads 120 .
In operation, a wafer 108 may be disposed on carrier tray 104 . Attachment devices 110 and 114 and attachment devices 126 and 130 attached to carrier tray 104 enable carrier tray 104 to glide along a path D between powered rail 112 and non-powered rail 128 , respectively. As carrier tray 104 carrying wafer 108 passes underneath cleaning portion 118 , process shower heads 120 apply cleaning solutions to the surface of wafer 108 . Process shower heads 120 then remove the cleaning solution via vacuum. In this manner, any particulates on the surface of wafer 108 are removed.
In a wet cleaning process, cleaning solutions are applied to the surface of wafer 108 in conjunction with de-ionized water delivery & mixed liquid-gas return lines. Goals during such a process include maintaining a balanced force on the surface of wafer 108 resulting from the application of liquid and gas flows and optimizing the efficiency of the wet clean process. Controlling forces applied to wafer 108 during a wet clean process may increase uniformity and residual removal rates across the entire wafer surface.
What is needed is a system and method for controlling forces applied to a wafer during a wet clean process in order to increase uniformity and residue removal rates across the entire wafer surface.
BRIEF SUMMARY
It is an object of the present invention to provide a system and method for controlling forces applied to a wafer during a wet clean process in order to increase uniformity and residue removal rates across the entire wafer surface.
In accordance with an aspect of the present invention, a method is provided for using a processing system that is operable to deposit liquid and to remove liquid by way of negative pressure. The method includes arranging a device to have at least one of the liquid deposited thereon by the processing system and the liquid removed therefrom by the processing system. The device has a sensor portion disposed thereon. The sensor portion can provide a sensor signal based on pressure related to the at least one of the liquid being deposited thereon by the processing system and the liquid being removed therefrom by the processing system. The method further includes performing at least one of depositing, by the processing system, the liquid onto the device and removing the liquid, by the processing system, from the device. The method still further includes providing the sensor signal, by the sensor portion, based on the pressure related to the at least one of the liquid being deposited onto the device and the liquid being removed from the device.
Additional objects, advantages and novel features of the invention are set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF SUMMARY OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate an exemplary embodiment of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1 illustrates a portion of a conventional linear wet chemical cleaning system 100 ;
FIG. 2 illustrates a characterization apparatus in accordance with an aspect of the present invention;
FIG. 3 shows a linear chemical cleaning and characterization system in accordance with an aspect of the present invention;
FIG. 4 shows a graph, which illustrates the signal response of each of the six sensors in a vibration sensor set during a particular cleaning process;
FIG. 5 shows a graph, which illustrates the signal response of two different sensors on a wafer during an example wet cleaning process;
FIG. 6 shows a graph, which illustrates the signal response of the sensors corresponding to functions in FIG. 5 during an example wet cleaning process, after appropriate adjustments have been made; and
FIG. 7 is a flowchart illustrating an example method of operation of the cleaning and characterization system of FIG. 3 in accordance with an aspect of the present invention.
DETAILED DESCRIPTION
In accordance with an aspect of the present invention, forces exerted on a wafer during semiconductor chemical cleaning process are monitored. Further, force vectors across the wafer surface area are extracted based upon wafer movement induced by liquids applied under pressure to the wafer surface during wet chemical clean processes. The monitored forces may then be used to adjust application of liquids and gases to the surface of a wafer and to adjust removal of materials from the surface of the wafer to optimize wafer yield.
Example embodiments of the present invention will now be described in reference to FIG. 2-FIG . 5 .
FIG. 2 illustrates a characterization apparatus 200 in accordance with an aspect of the present invention:
As illustrated in FIG. 2 , characterization apparatus 200 includes a wafer 202 , a sensor signal conduit 204 , an analog-to-digital converter (ADC) 206 , a digital signal processor (DSP) 208 and a tool controller 210 . Wafer 202 includes a set of vibration sensors 224 integrated on the surface. In an example embodiment, vibration sensors 224 are piezoelectric devices. In this particular embodiment, vibration sensor set 224 includes six sensors: sensor 212 (sensor # 6 ), sensor 214 (sensor # 4 ), sensor 216 (sensor # 2 ), sensor 218 (sensor # 1 ), sensor 220 (sensor # 3 ), and sensor 222 (sensor # 5 ).
In operation, wafer 202 is placed in cleaning system 100 and a given cleaning process begins. During the cleaning process, the sensors in vibration sensor set 224 each measure the local forces exerted on wafer 202 , such as the forces due to the application of cleaning solution, the application of de-ionized water, and the removal of such liquids, residues and particulates with a vacuum. The individual signals from vibration sensor set 224 are passed to ADC 206 via sensor signal conduit 204 , which are then passed through DSP 208 and eventually to tool controller 210 . Tool controller 210 may be a program that displays and records the signal responses from each sensor in vibration sensor set 224 .
The operation discussed above is illustrated in FIG. 3 . FIG. 3 shows a linear chemical cleaning and characterization system 300 in accordance with an aspect of the present invention.
Cleaning and characterization system 300 includes cleaning system 100 and characterization apparatus 200 . As shown in the figure, wafer 202 , which includes vibration sensors set 224 , is placed in cleaning system 100 . As discussed above, the signals from vibration sensor set 224 sense the various local forces on wafer 202 during the cleaning process. These individual sensor responses can be monitored and then correlated to specific process conditions, as will be discussed further with reference to FIG. 4 .
FIG. 4 shows a graph 400 , which illustrates the signal response of each of the six sensors in vibration sensor set 224 during a particular cleaning process.
In graph 400 , the x-axis is time, in seconds, whereas the y-axis is the sensor output, in millivolts, of each particular sensor. Graph 400 includes function set 402 , a set of signal responses from the sensors in vibration sensor set 224 . In this embodiment, there are six individual functions, one from each sensor in vibration sensor set 224 .
Initially, the behavior of the responses in function set 402 is fairly constant, as wafer 202 begins gliding across holding tray 102 . However, around point 404 , a significant shift is present in each of the sensors responses. This can be correlated to wafer 202 beginning to move beneath process shower heads 120 , and may represent the forces of the cleaning solution being applied to the surface of wafer 202 . Shortly after point 404 in function set 402 , there is a very sharp transient at point 406 . This can be correlated to process shower heads 120 vacuuming the cleaning solution from the surface of wafer 202 .
After the transient near point 406 settles, the responses in function set 402 remain somewhat constant before experiencing a sharp negative transient around point 408 . This transient can be correlated to the point where wafer 202 has completed the pass beneath process shower heads 120 and the vacuum is no longer removing liquid from the surface of wafer 202 .
As mentioned earlier, the individual responses in function set 402 represent the forces seen by the individual sensors in vibration sensor set 224 . Therefore, the individual responses in function set 402 can provide a spatial map of the forces seen across wafer 202 during a given cleaning process. This allows any areas of non-uniformities or non-idealities in the way forces are applied to wafer 202 to be identified during the cleaning process. For example, for a given wafer 202 , there may be maximum threshold of pressure that may be applied to it, above which may potentially cause damage or even breakage. Therefore, by monitoring the local forces on wafer 202 during the cleaning process, one can check if the applied pressure at any location on wafer 202 (from the application of cleaning solution, vacuum, etc) exceeds this given threshold. If so, then various processing parameters (such as amount of water or cleaning solution dispensed during cleaning, force or duration of vacuum, etc) may be appropriately adjusted to reduce the pressure on wafer 202 .
In addition to maximum pressure threshold, there may be other pressure-related thresholds pertinent to a given wafer. For example, there may be a threshold for the maximum change in pressure over a given distance on the wafer. This may be monitored by examining the difference between individual sensor responses. Also, there may be a threshold for maximum change in pressure over a given time. This may be monitored by examining the gradient of the individual sensor responses as a function of time. In any case, if a threshold is exceeded, processing parameters may be adjusted to reduce the changes in pressure. For example, the rate at which water or cleaning solution is applied to wafer 202 or the force of the vacuum may be appropriately adjusted in order to reduce sudden changes in pressure during the cleaning process. Also, if process shower heads 120 are movable, they may be moved and rearranged such as to provide more uniform pressure across the surface of wafer 202 .
Once the processing parameters are adjusted, wafer 202 undergoes the cleaning process again and the resulting effects on the sensor responses are observed. The cycle of processing and observing followed by adjusting of processing parameters may be repeated several times until the results are deemed to be acceptable (all sensor outputs fall within set thresholds). In this manner, wafer damage during cleaning can be avoided or reduced, thereby improving the yield and efficiency of the wet cleaning process. Once the cleaning process has been sufficiently optimized, wafer 202 may be removed and the cleaning process may be performed on regular production wafers.
For the sake of discussion, the ability to adjust the cleaning system to account for sensor outputs surpassing given thresholds will now be described in reference to FIGS. 5 and 6 .
FIG. 5 shows a graph 500 , which illustrates the signal response of two different sensors on wafer 202 during an example wet cleaning process.
In graph 500 , the x-axis is time, in seconds, whereas the y-axis is the sensor output, in millivolts, of each particular sensor. Graph 500 includes function 502 and function 504 , which represent signal responses from different sensors in vibration sensor set 224 on wafer 202 . For simplicity, in graph 500 , the signal responses from only two sensors are shown.
Graph 500 also includes maximum negative pressure threshold 506 and maximum positive pressure threshold 508 . These indicate a predetermined maximum amount of negative pressure and predetermined maximum amount positive pressure that may be applied to an area on wafer 202 , respectively, before a likelihood of damage to wafer 202 will exceed a predetermined likelihood of damage threshold. These thresholds may be experimentally determined by monitoring yield of batched of cleaned wafers.
As shown in graph 500 , at point 512 , function 502 exceeds maximum positive pressure threshold 508 . This indicates that the pressure at this sensor is too high and needs to be reduced, in order to reduce the likelihood of wafer damage below the predetermined likelihood of damage threshold. At point 516 , function 502 does not surpass the maximum negative threshold 506 , so the value of pressure there is acceptable.
However, note that there is a large change in pressure between point 514 on function 504 and point 516 on function 502 . Since the points are relatively close in time, the difference in pressure between points 514 and 516 (noted as d s1 ) represents the change in pressure sustained over the physical distance between the two sensors. In this example, presume the pressure change d s1 divided by the distance between the two sensors is found to exceed a predetermined threshold for pressure change per distance on wafer 202 . A predetermined threshold for pressure change per distance on wafer 202 is a threshold of pressure change per distance on wafer 202 before a likelihood of damage to wafer 202 will exceed a predetermined likelihood of damage. Since this threshold is exceeded, this is unacceptable and must be addressed.
In addition to changes in pressure over distance, there may also be established thresholds for changes in pressure over time. At point 518 on function 502 , the gradient with respect to time is indicated by a line (line 520 ). As one can see, line 520 is almost completely vertical, indicating a very large change in pressure over time. In this example, presume the gradient at point 518 exceeds a pre-determined threshold for change in pressure with respect to time. A predetermined threshold for pressure change with respect to time is a threshold of pressure change at a position on wafer 202 over time before a likelihood of damage to wafer 202 will exceed a predetermined likelihood of damage. Since this threshold is exceeded, this is unacceptable and must be addressed
Thus, in graph 500 , there are three different instances where pre-determined thresholds were exceeded: 1) at point 512 , the sensor corresponding to function 502 has exceeded the maximum (positive) pressure threshold; 2) between points 514 and 516 , the threshold for maximum change in pressure over distance was exceeded; 3) at point 518 , the sensor corresponding to function 502 has exceeded its threshold for maximum change in pressure with respect to time. All these must be addressed by appropriately adjusting the pressure sensed by the sensors corresponding to functions 502 and 504 . As previously mentioned earlier, these adjustments may be accomplished in a variety of ways, such as adjusting the rate at which water or cleaning solution is applied, or adjusting the force and/or duration of the vacuum. Also, if process shower heads 120 are moveable, they may be rearranged such as to provide more uniform pressure to all the sensors. Once adjustments are made, the cleaning process may be run again and the new sensor outputs can be monitored to check if they fall within the established thresholds. This will be described in more detail with respect to FIG. 6 .
FIG. 6 shows a graph 600 , which illustrates the signal response of the sensors corresponding to functions 502 and 504 in FIG. 5 during an example wet cleaning process, after appropriate adjustments have been made.
In graph 600 , the x-axis is time, in seconds, whereas the y-axis is the sensor output, in millivolts, of each particular sensor. Graph 600 includes function 602 and function 604 , which represent signal responses from different sensors in vibration sensor set 224 of wafer 202 . Function 602 corresponds to the same sensor that was associated with function 502 in FIG. 5 , and function 604 corresponds to the same sensor that was associated with function 504 in FIG. 5 .
As shown in FIG. 6 , function 602 and 604 are now different from functions 502 and 504 , due to adjustments in the cleaning process. Specifically, the maximum value of function 602 (point 606 , which corresponds to point 512 on function 502 ) has been reduced, and now does not exceed the maximum positive pressure threshold 508 . Also, the minimum value of function 602 (point 610 , which corresponds to point 516 on function 502 ) has become less negative, such that the difference between point 608 of function 604 and point 610 of function 602 (denoted as d s2 ) is now smaller than the maximum threshold for change in pressure over distance. Further, at point 612 on function 602 (which corresponds to point 518 on function 502 ), the gradient with respect to time (shown by line 614 ) has been reduced, such that it now falls within the threshold for maximum change in pressure over time. Thus, one can see that in FIG. 6 all the issues with sensors exceeding their predetermined pressure thresholds have been addressed via adjustments to the cleaning process. Now that the sensor outputs are within acceptable thresholds, there is less likelihood of wafer damage during the cleaning process, which thereby provides for a more efficient and higher-yield cleaning process.
An example method of operating cleaning and characterization system 300 in accordance with an aspect of the present invention will now be described with reference to FIG. 7 .
Process 700 starts (step S 702 ) and process initializations occur (step S 704 ). Non-limiting examples of process initializations include, establishing data communications or positioning parts in cleaning and characterization system 300 . Process initializations may also include setting various process parameters such as the specific amount of water or cleaning solution to be applied (controlled by flow rate, etc), strength of the vacuum, and the specific time(s) when cleaning solution and/or vacuum is to be applied (and the duration of time applied). Also, initializations may include establishing thresholds for the pressure applied to wafer 202 , as discussed previously (e.g. maximum pressure, maximum change in pressure with respect to distance, time, etc). Further, if process shower heads 120 are moveable, their initial position would be set in this step.
Then, a sensor wafer is loaded (step S 706 ). Returning to FIG. 3 , wafer 202 , with vibration sensor set 224 integrated on its surface, is disposed on carrier tray 104 .
Wafer 202 is then processed in cleaning and characterization system 300 (step S 708 ).
After wafer 202 is processed, the individual sensor outputs of vibration sensor set 224 are monitored (step S 710 ). The results are analyzed to determine if the individual sensor outputs of vibration sensor set 224 are all acceptable (all fall within the established thresholds) for the given process (step S 712 ).
If any of the individual sensor outputs of vibration sensor set 224 are not deemed to be acceptable, then the appropriate process parameters are adjusted (step S 714 ) and wafer 202 is processed again (step S 708 ) with the new parameters. As discussed previously with reference to FIG. 4 , the adjustments to process parameters may include adjusting the flow rate of water and/or cleaning solution from process shower heads 120 , the position of process shower heads 120 (if movable), and/or the strength of vacuum used to remove cleaning solution and particles from the surface of wafer 202 . The adjustments may be implemented manually or via an automatic feedback control system.
Returning to step S 712 , if all individual sensor outputs of vibration sensor set 224 are deemed to be acceptable, then wafer 202 is removed from carrier tray 104 and a production wafer is loaded onto carrier tray 104 (step S 716 ).
The production wafer is then processed (step S 718 ).
After the production wafer is processed, it is determined whether more production wafers need to be processed (step S 720 ). If the determination is NO, then processing may conclude (step S 722 ). Otherwise the next production wafer is loaded (step S 716 ) and the process repeats.
In the above process, thresholds for certain parameters (maximum pressure on wafer, etc) are first established during initialization (step S 704 ) and later the sensor outputs are checked to ensure they are all within the given thresholds (step S 712 ). However, it may be the case that the parameter thresholds are not known prior to processing. Thus, in this case, the initialization step (step S 704 ) would just include the other process initializations (positioning of process shower heads 120 , setting strength of vacuum, etc) and step S 712 may just include a general overview of the sensor outputs to determine whether or not the results are acceptable. If the sensor outputs are deemed unacceptable, then the process would go on to step S 714 to adjust appropriate processing parameters, just as discussed previously.
In the embodiment discussed above with reference to FIG. 2 , vibration sensor set 224 includes individual piezoelectric films. It should be noted however, that other embodiments may include sensors of other types, non-limiting examples of which include, sensors made of microelectrical mechanical systems (MEMs). Further, it should be noted that other embodiments may include any number of sensors integrated on the surface of wafer 202 , in any sort of pattern.
In the embodiments discussed above in FIGS. 2-7 , sensors are used to measure forces on a wafer during a wet clean process. It should be noted, however, that other embodiments may include sensors or other measuring devices that measure other parameters on a wafer during processing, non-limiting examples of which include temperature or acidity.
In the embodiments discussed above in FIGS. 3-7 , forces on a wafer during a wet chemical cleaning process are monitored and optimized. It should be noted, however, than an aspect of the present invention is not limited to use with wet chemical cleaning systems. On the contrary, an aspect of the present invention may be implemented with any semiconductor system of interest. For example, the methodology can be applied to chemical mechanical polishing (CMP) processing systems to monitor pressure distribution across a wafer, or in MEMs applications where a spatial analysis of these stresses exerted on a substrate is required. Further, the methodology may be used in other systems to characterize the chucking force applied to a wafer by an electrostatic chuck (ESC). Specifically, the characterization apparatus in FIG. 2 may be used to measure the forces on a wafer applied by the chucking voltage of an ESC and therefore can allow for the examination of the uniformity of the clamping force across the wafer. By monitoring each sensor, a spatial map can be constructed of the relative clamp force at each sensor location, providing feedback to the user during ESC development as well as providing a problem-solving tool for chucking and de-chucking issues.
The foregoing description of various preferred embodiments of the invention have 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, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments, as described above, were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
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A method of using a processing system that is operable to deposit liquid and to remove liquid by way of negative pressure. The method includes arranging a device to have at least one of the liquid deposited thereon by the processing system and the liquid removed therefrom by the processing system. The device has a sensor portion disposed thereon. The sensor portion can provide a sensor signal based on pressure related to the at least one of the liquid being deposited thereon by the processing system and the liquid being removed therefrom by the processing system. The method further includes performing at least one of depositing, by the processing system, the liquid onto the device and removing the liquid, by the processing system, from the device. The method still further includes providing the sensor signal, by the sensor portion, based on the pressure related to the at least one of the liquid being deposited onto the device and the liquid being removed from the device.
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FIELD OF THE INVENTION
The present invention relates generally to buffering events in a computer system in a memory and accessing this memory in way that provides the maximum mount of information with the fewest accesses.
BACKGROUND
In a computer system, various events are detected by the hardware and must be subsequently handled by a processor. These events include signals received on inbound Input/Output (I/O) interfaces, power and cooling systems alerts, error conditions, and failure conditions. Sometimes these events can happen faster than they can be handled in real time by the processor. To overcome this, a small memory element is typically added to the system to temporarily store the events until they can be handled by the processor. The memory element is often structured as a first-in, first-out (FIFO) buffer in a communication system.
When the processor is physically and logically located at a distance from the FIFO, each access that the processor makes to read the FIFO takes a considerable amount of time. As processors get faster, the number of processor cycles consumed waiting for the returned FIFO data increases. As this problem has been recognized, other related problems have been experience during development. When the FIFO fills with many events, the processor must access the FIFO for each event in the FIFO. Each time an event is put into the FIFO, the system causes an interrupt to the processor. These events cause considerable overhead to the processor since the processor typically makes a context switch to software used to handle the interrupt.
SUMMARY OF THE INVENTION
It has been recognized that it would be desireable to present the maximum information to a processor each time it reads the FIFO buffer in a communication system. This invention presents different information depending on the state of the FIFO (its fullness), and the state of the system. The preferred embodiment for a computer system having a communication link processor and employing a FIFO buffer and controling an asynchronous event storing and recording mechanism to write discreet events into the FIFO at a location determined by a write pointer; and then reading with the attached communication link processor reading the recording mechanism's FIFO at a location determined by a read pointer. Then the recording mechanism conditionally returns event and status information and conditionally increments the FIFO read pointer.
In accourdance with the preferred embodiment a fullness indication of the FIFO is returned in the read information as the value of the FIFO read pointer and write pointer. Furthermore, the recording mechanism returns system status when the FIFO is completely empty; and an event description when the FIFO has one or more valid entries.
The preferred embodiment of the invention has a mode where the processor can read multiple entries of the FIFO using a single command. Once again, the format of the returned data is different from the variable information returned by a single FIFO access.
It is another object of the present invention to reduce the number of interrupts presented to the processor by sharing information as to the fullness of the FIFO as observed by the processor and known to the FIFO.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIG. 1 illustrates a system containing a processor and an event FIFO including its controls;
FIG. 2 illustrates the internal controls of the event FIFO;
FIG. 3 illustrates the data returned from the FIFO in different states and by different data paths; and
FIG. 4 illustrates a flowchart of the actions taken to control the interrupts to the processor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows the relationship of a central processor 102 to an event recording mechanism 104 that captures various events 110 , 112 , 114 , 116 from various sources within a computer system. While the current invention relates specifically to events received from an Inoup/Output interface, this invention could just as well be used in any apparatus used to record events from a wide variety of sources. For example, the recording mechanism could be applied to a system used to monitor many different kinds of events such as system errors, temperature alerts, etc. The processor 102 comprises a main memory 108 . Within the recording mechanism is a circular FIFO 120 and control logic. The connection between the processor 102 and the recording mechanism 104 is a computer bus 106 comprising several functions:
1) The ability for the processor to load information from the recording mechanism into one of the processor's general registers,
2) The ability of the processor to store information into the recording mechanism from one of the processor's general registers,
3) The ability of the recording mechanism to store blocks of data into the processor's main memory, and
4) The ability of the recording mechanism to send interruption signals to the processor.
Typically, the processor handles multiple recording mechanisms 122 within a system.
FIG. 2 shows the internals of the recording mechanism 102 of FIG. 1 . FIFO buffer 202 is implemented as a linearly addressable array and has space for 256 entries; each entry is 8 bytes. A different size buffer could be used, and the pointer sizes could be adjusted accordingly. The write pointer 204 is controlled by the recording mechanism and points to the next entry in the FIFO to be written when the next event occurs. After writing an event, the control logic increments the write pointer by 1 206 . The read pointer 208 is directly and indirectly controlled by the processor and points to the next entry in the FIFO that the processor will read. After the processor reads the FIFO using a load instruction, the controls automatically increment the read pointer by 1 210 only if the write pointer 204 value is not equal to the read pointer 208 . If the two pointer values are equal, the FIFO is completely empty (as described below), and no change is made to the read pointer 208 . The processor also has the capability of setting the read pointer to any value over path 212 using a store instruction. Each pointer 204 , 208 is 8 bits, and when the pointers have equal values, the FIFO is defined to completely empty rather than completely full. As a consequence, the FIFO never has more than 256−1 (255) valid entries, and the recording mechanism control hardware ensures that the FIFO will never have more than 255 valid entries. A FIFO overrun condition is detected if more events occur than there is space for in the FIFO. When entries are written into the FIFO, write pointer 204 is gated through the multiplexor (MPX) 214 to the FIFO 202 . When entries are read by the processor, read pointer 208 is gated through multiplexor 214 to the FIFO 202 .
The event data 220 includes a description of the event 222 and a time stamp 224 used primarily as a debug tool. Compare circuit 230 compares the write pointer 204 to the read pointer 208 . When the two pointers have the same value 232 , the FIFO is completely empty. When the pointers differ by exactly one, that is, the write pointer is ahead of the read pointer by exactly 1, or the read pointer+1 equals the write pointer, there is exactly one valid entry 234 in the FIFO. This information 234 is part of the interrupt presentation to the processor and is described below. When the FIFO is completely empty, mupliplexor (MPX) 240 gates the system status 242 back to the processor when the processor reads the FIFO. When the FIFO is not completely empty, the multiplexor 240 gates the event description from the FIFO entry back to the processor. In either case when the FIFO is either completely empty or not completely empty, the value of the write pointer 204 , read pointer 208 , and interrupt source information 250 is always returned to the processor. The interrupt source information tells the software of any other sources of the interrupt other than FIFO entries. All of this information is read over data path 244 when the processor reads a FIFO entry using its load instructions. The log pointer 260 is loaded from the processor over path 264 when the processor wants the recording mechanism to automatically store one of more FIFO entries directly into the processor's main memory. In this case, data path 246 is used by the recording mechanism, and this path includes different information from data path 244 , as described below.
FIG. 3 shows the formats of the data generated by the recording mechanism. The data returned to the processor when it reads a FIFO entry and the FIFO is completely empty 302 includes the value of the write pointer 304 , the read pointer 306 , the system status 308 , and interruption source information 310 . When the processor software receives this information, it first examines the write pointer 304 and the read pointer 306 . In this case, these pointers are equal, so the software knows that the rest of the data includes the system status 308 and interrupt source information 310 . If the processor reads the FIFO as a result of an interrupt, it is likely that the interrupt source information indicates some interrupt other than a FIFO event. The data returned to the processor when it reads a FIFO entry and the FIFO is not completely empty 322 includes the value of the write pointer 324 , the read pointer 326 , the description of the system event 328 (the FIFO entry), and interruption source information 330 . When the processor software receives this information, it first examines the write pointer 304 and the read pointer 306 . In this case, these pointers are not equal, so the software knows that the rest of the data includes a description of the event 328 (the FIFO entry) and interrupt source information 330 . If the processor reads the FIFO as a result of an interrupt, in this case it is likely that the FIFO has an event for the software, but the interrupt source information may indicate some additional interrupt source other than a FIFO event.
FIG. 3 also shows the format of the data used when the recording mechanism is instructed to store a block of FIFO data into the processor's main memory. Each 8 bytes 342 includes the FIFO event descriptions 344 , but instead of current status conditions (including write pointer and read pointer values, system status, and interrupt source information), a time stamp 346 from the FIFO entry is included. The processor retrieves multiple entries from the FIFO when it wants to log activity for problem determination or read many entries because there are too many to be efficiently read using individual load instructions.
When the processor wants to read multiple entries from the recording mechanism, it first loads the log pointer 260 to the starting location in the FIFO where it wants the recording mechanism to start reading entries. The processor then sends a command to the recording mechanism telling it how many entries to store into the processor's main memory and the starting address in the processor's main memory. The main memory address is on an 8 byte boundary. The recording mechanism starts reading the FIFO entries at the current log pointer address and if it reaches the end of the FIFO array before the entry count of the command is exhausted, it wraps back to the beginning of the FIFO array. In this way, the contents in main memory always progresses from the oldest entry in the FIFO to the newest entry in the FIFO. After the recording mechanism finishes storing the data into the processor's main memory, it sets an indicator in the system status that can be examined by the processor. Also, the recording mechanism can be instructed in the log command to send an interrupt to the processor. After the processor determines that the recording mechanism has finished storing the data into its main memory, it can advance the read pointer to ‘skip over’ the entries that the recording mechanism stored.
FIG. 4 is a flowchart of how interruptions to the processor are generated by the recording mechanism. Typically in the previous art, each time an event is stored into the FIFO, an interrupt is generated to the processor. Interrupts require a lot of processor overhead, so the recording mechanism only sends interrupts when the processor wants them. For the recording mechanism to detect when the processor wants to receive an interrupt, it uses a latch called the Block FIFO Interrupt latch. Each time the processor reads the FIFO using its load instruction 402 , the recording mechanism compares the value of the write pointer and read pointer returned in the data to the processor. Since the values examined by the recording mechanism are the same as those returned to the processor, the recording mechanism knows that the processor will make the same decisions and is in synchronism with the recording mechanism. If the values of the write pointer and read pointer are the same 404 , the FIFO is completely empty and the processor will want an interrupt when the next FIFO entry is made. Otherwise 406 , if the value of the write pointer is ahead of the read pointer by exactly one 408 , there is exactly one entry in the FIFO, and this entry is being returned to the processor by this reading of the FIFO. After the read operation, the read pointer is incremented by one, as explained in the description of FIG. 2, and the write pointer is equal to the read pointer. As a result, if the write pointer and read pointer indicate that the FIFO is either completely empty of has exactly one entry, both the recording mechanism and the software agree that an interrupt will be generated when the next FIFO entry is made. Returning to FIG. 4, the Block FIFO Interrupt latch is reset 410 allowing the next FIFO event to cause an interrupt if the last FIFO read indicated that the FIFO was either completely empty or had exactly one entry; and the Block FIFO Interrupt latch is set 412 when the FIFO has more than one entry. When the FIFO has more than one valid entry, the recording mechanism knows that the software will continue to read FIFO entries until there is either exactly one valid entry or until the FIFO is completely empty. In this case, subsequent FIFO entries do not require an interrupt to be sent to the processor.
FIG. 4 also shows what happens when the recording mechanism makes a FIFO entry 420 . After the entry is made, the recording mechanism checks the state of the Block FIFO Interrupt latch to see it if should send an interrupt to the processor. If the Block FIFO Interrupt latch is set 422 , no interrupt is generated and the recording mechanism is finished 424 . If the Block FIFO Interrupt latch is not set 426 , in interrupt is sent 428 to the processor.
The flowchart in FIG. 4 also shows what happens when the processor stores into the read pointer using a store instruction 430 . If the write pointer is not equal to the read pointer 432 , the FIFO has at least one entry, so the recording mechanism sends an interrupt to the processor 428 to inform it of this condition. If the Write pointer is equal to the read pointer 434 , the FIFO is empty and the recording mechanism resets the Block FIFO Interrupt latch 436 to allow the next FIFO entry to send an interrupt to the processor.
While the preferred embodiment to the invention has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.
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A method and system for a processor to efficiently accesses a remote First-in First-out (FIFO) buffer that is used to record event information. The access involves an interrupt mechanism when the FIFO transitions from the empty state, a mechanism for reading a FIFO entry including FIFO state information, and a mechanism for reading large areas of the FIFO while maintaining the pointers and interrupt protocols.
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RELATED APPLICATIONS
This application is a continuation-in-part of Application Ser. No. 884,690, filed on Mar. 8, 1978, entitled "Snow Plow" now U.S. Pat. No. 4,187,624.
FIELD OF THE INVENTION
The present invention relates generally to the art of snow plows and more particularly to snow plows of the type which are suitable for use with small vehicles, such as cars.
BACKGROUND OF THE INVENTION
Many different types of snow plows are known to the art. Conventional plows include a blade and a frame for coupling the blade to the front of a vehicle. More sophisticated plows also include means for adjusting the angular orientation of the plow blade relative to the longitudinal axis of the vehicle for elevating the plow blade relative to the road surface to permit the vehicle to be driven from one location to another.
Prior art snow plows are also known for use with many different sizes of vehicles. For example, plows are known which can be used with very large vehicles. These plows are typically used for large snow removal jobs such as airport runway clearing and the like. Smaller plows are known which can be coupled to dump or garbage trucks for use in road clearing operations, and still smaller snow plows are known which may be coupled to yet smaller trucks for use in driveway or parking lot clearing and the like. A typical example of the latter would be the type of plow frequently employed by the owner of a gasoline station for use with his tow or pick-up truck. Following a snowfall, such a plow would be coupled to the front end of the tow truck for use in clearing the station as well as for other snow clearing jobs in the neighborhood.
The type of plow just referred to is usually quite expensive, requires considerable time to attach to a vehicle, and includes structural features which makes them impractical for use with cars. For example, such plows commonly include a hydraulic pump assembly mounted externally on the vehicle, a feature which increases the exposure of the operating components to adverse weather conditions and increases the likelihood of theft or vandalism of the equipment. Moreover, such plows also include a bulky, viewobstructing plow lifting system mounted immediately adjacent the front end of the vehicle which includes a hydraulic cylinder oriented upwardly to engage a lifting arm which in turn is coupled to the plow by a chain. Extension of the cylinder causes the arm to be elevated which causes the chain to lift the plow blade above the road surface. This type of lift system, both because of its bulk and because of its tendency to shift weight off the back wheels of the vehicle, make this type of plow unsuitable for smaller vehicles such as cars. Typical examples of this type of plow are described in Simi's U.S. Pat. No. 3,307,275, issued Mar. 7, 1967, for "Vehicle Accessory Unit and Power Unit Therefore," and in Micelli's U.S. Pat. No. 3,706,144 issued Dec. 19, 1972, for "Control Means for a Snowplow."
Another related type of snow plow is described in Jackoboice's U.S. Pat. No. 3,524,269, issued Aug. 18, 1970, for "Mounting Means for Vehicular Implements." This device is different from that described above in that instead of using a vertical frame and upwardly directed hydraulic cylinder for raising the plow, it employs a horizontal cylinder which rotates a round member mounted to the plow blade frame to lift the plow. The vehicle's bumber supports one end of a lifting chain. The other end of the chain is attached to the round member and is wound therearound at the discretion of the driver to cause shortening of the chain length and resultant lifting of the blade. While the lifting mechanism is different, this type of plow still suffers from the same disadvantages as those discussed above which significantly impair the adaptability of this type of plow for use with small vehicles, such as cars.
Yet another type of lifting system for plow blades and the like is illustrated in Holopainen's U.S. Pat. No 3,165,842, issued Jan. 19, 1965, for "Mechanism for Attaching Implements to Vehicles." In the described device a link is located intermediate the subframe assembly and the implement and a cylinder acts on the link to rotate it and push the implement upward.
None of the aforementioned systems are entirely satisfactory for use with small vehicles, such as cars. This special utility requires ease of attachment, a lift system which will not obstruct the driver's view and a blade lift system which does not cause detrimental weight distribution problems or alter the vehicle's normal driving characteristics. The development of a snow plow assembly which would satisfy these objects and overcome the difficulties of the prior art would be a significant advance in this technology. Moreover, the provision of a snow plow assembly which permits flexibility in the selection of a suitable location for mounting the hydraulic components would be a further advance in this technology.
OBJECTS OF THE INVENTION
It is the primary object of the present invention to provide a snow plow assembly which can be used on a variety of sizes of vehicles, including fuel-efficient small cars.
Another object of the present invention is to provide a snow plow assembly, the hydraulic components of which can be mounted in the vehicle's engine compartment, on the plow support assembly or on the subframe assembly used to couple the plow to the vehicle.
Still another object of the present invention is to provide a snow plow assembly which can be quickly coupled to or uncoupled from a vehicle.
How these and other objects of the invention are accomplished will be described in the following specification, taken together with the FIGURES. Generally, however, they are accomplished by providing a vehicle subframe assembly coupled to the chassis of a vehicle, such as a car. A generally triangular plow support frame assembly is coupled to the subframe assembly by two pins. The plow frame support assembly includes a plow blade at its forward end as well as three hydraulic cylinders, two of which are for horizontally varying the angular orientation of the blade with respect to the longitudinal axis of the vehicle, and the third one of which is provided for lifting the plow blade with respect to the road surface. Each of the cylinders are coupled to a hydraulic system, the major components of which may be located within the engine compartment of the vehicle, on the plow assembly or on the subframe. Quick connections are preferably made near the vehicle's front bumper and the controls for the cylinders are mounted in the vehicle at or near the dash board.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the snow plow assembly according to one preferred embodiment of the present invention;
FIG. 2 is a detailed side view of the bell crank lifting system of the present invention;
FIG. 3 is a schematic of the hydraulic system of the present invention;
FIG. 4 is a partial perspective view, with parts omitted, of the snow plow assembly shown in FIG. 1 in which the hydraulic components are mounted to the plow support assembly; and
FIG. 5 is a partial perspective view, with parts omitted, of the snow plow assembly shown in FIG. 1 in which the hydraulic components are mounted to the vehicle subframe assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a perspective view of a snow plow assembly 10 according to one embodiment of the present invention. Assembly 10, as illustrated, is coupled to the front end of a car 12, but the invention is not limited for use with cars. While it is true that the snow plow of the present invention is especially useful for smaller, fuel-efficient vehicles with which other commercially available plows are not suitable, assembly 10 could be readily adapted for use with jeeps, recreational vehicles, pick-up trucks, tow trucks and other types of trucks. Moreover, the system could be used with other vehicles such as tractors, bulldozers and the like.
A coupling frame 14 is also shown in FIG. 1, frame 14 including two side bars 15, and a front connecting member 16. Side bars 15 are parallel to one another and are preferably made of angle steel and extend from an area generally below the front bumper 20 of vehicle 12, along the bottom of the vehicle chassis just inside the wheel to an area typically near the vehicle's transmission mount (not shown). The side members 15 are bolted or otherwise securely fastened to the chassis and preferably to the front holddown brackets, but the details thereof are not provided because the particular configuration of side bars 15 will depend on the type of car 12 with which they are to be used. It should be mentioned, however, that the system employed for mounting side bars 15 should facilitate the easy coupling and uncoupling of frame 14 to the car, since frame 14 would not normally be employed during warm weather.
The front connecting member 16 is welded between the forward ends of side bars 15 generally below the car's front bumper 20. Again, this member is preferably constructed of steel. A pair of brackets 24, which in the illustrated embodiment comprise a pair of forwardly extending short plates 26, having axially aligned holes, are provided on front member 16 just inwardly of the corners of the car 12.
The second major component of the plow assembly is a plow blade support frame 30 which comprises a generally triangular frame consisting of a rear side member 31 and forwardly extending side members 32. Each component is preferably constructed of angle steel. Frame 30 also includes a pair of coupling plates 35 which are welded to frame 30 adjacent the rear corners thereof, plates 35 being arranged and adapted for being inserted between the brackets 24 of frame 14. The coupling plates 35 also include a hole therethrough so that quick disconnect pins 37 may be inserted through the three aligned holes to pivotally couple blade support frame 30 to frame 14. It will be appreciated then that the forward end of frame 30 is movable about a circular arc having an axis defined by pins 37.
A conventional plow blade 40 is pivotally connected to the forward end of support frame 30 so that the horizontal orientation of the blade may be adjusted relative to the axis of the vehicle and the means provided for controlling such horizontal orientation will be discussed in a later section of this specification. Blade 40 also includes a semi-circular swivel plate 42 welded to the back of the blade. The plate 42 includes a flat horizontal surface 43 and a vertical ridge 44 on the inner surface of the arc forming a track-like segment. A small triangular plate 45, is welded to the front of the support 30, the bottom of segment being slidably received thereon. A restraining bracket 46 is bolted to triangular plate 45 to prohibit vertical movement of swivel plate 42 with respect to plate 45, while permitting sliding movement of the horizontal surface 43 thereunder.
FIG. 1 also shows the snow plow assembly 10 to include a pair of springs 48 which permit the blade 40 to tip relative to the road surface if an obstruction is encountered. Springs 48 are connected between a pair of vertical supports 50 welded onto either side of swivel plate 42 and a pair of adjustable eyelets 51 secured generally near the top of blade 40 on the back side thereof. Eyelets 51 include threaded stems 52 and lock nuts to vary the length of springs 48 and in turn control the tension applied thereby. Eyelets 51 are secured to the upper portion of the blade 40 through a pair of brackets 54. From this description it should be understood that, if the bottom of plow blade 40 is obstructed during forward movement of the vehicle, the top of blade 40 will tip forwardly to allow the lower edge of the blade to pass over the obstruction.
Before proceeding with the description of the blade maneuvering system, it should be pointed out that other conventional equipment may be employed with the snow plow assembly 10. For example, adjustable skids (not shown) can be mounted to the blade support or the blade itself for displacing the blade by a preselected distance from the road surface. Likewise, any shape of plow blade may be employed, whether it be of the concave variety shown in the FIGURES or of the V-shaped design known the the art.
Referring again to FIG. 1, snow plow assembly 10 also includes a pair of hydraulic cylinders 60 and 61, for controlling the horizontal orientation of blade 40. Cylinders 60 and 61 each include an extensible piston rod 62 and 63 and hydraulic fluid hoses 64 and 65 respectively. The cylinders themselves are pivotally mounted to brackets 66 on the rear side 31 of blade support 30 and are spaced apart from one another but are relatively nearer the axis of the vehicle 12. The piston rods 62 and 63 are pivotally mounted to brackets 67 and the arcuate segment 42 intermediate the vertical supports 50 and the connections of segment 42 to the blade 40. In this manner, it can be seen that extension of piston rod 61 and corresponding retraction of the other pistion rod 62 will result in movement of the blade toward the right, and vice versa.
By further reference to FIG. 1 and now by reference also to FIG. 2, the blade lifting mechanism of the present invention can be understood. A third hydraulic cylinder 72, having a piston rod 73, and fluid hose 74, is pivotally coupled to bracket 75 located at the middle of rear side 31 of blade support 30. In this position, piston rod 73 is oriented generally toward triangular plate 45. Another bracket 76 is mounted horizontally to the rear surface of plate 45, bracket 76 including a pair of parallel plates 77 having aligned holes (not shown). Yet another bracket 79 is provided behind the car's bumper (see the cut-away portion of FIG. 1), bracket 79 in turn being welded to an elongated steel lift bar member 81 which is ridigly secured to the front of car 12 on the vehicle's bumper bracket (not shown) or to the car's frame. Bracket 79 also includes a pair of parallel short plates 80 having aligned holes therein, but this bracket is directed generally downwardly and slightly forwardly.
A bell crank assembly 85 is mounted between brackets 76 and 79 and the end of piston rod 73 as will now be described. Assembly 85 includes a first generally Y-shaped link member 86 which includes symmetrical side plates 87 and 88. Plates 87 and 88 are welded to one another at the top of link 86 and fit between the plates 80 of bracket 79 and are pivotally secured thereto by pin 90. Side plates 87 and 88 diverge from one another below bumper 20 and then are bent so as to be parallel to one another. A hole (not shown) is provided at the lower end of each of plates 87 and 88.
A second link member 92 is also included in crank assembly 85. Link 92 also includes a pair of side members 94 and 95 each of which is generally L-shaped, the angle between the long and short portions of sides 94 and 95 actually being acute in the preferred embodiment. The long portions of sides 94 and 95 are pivotally mounted to bracket 76 (by pin 97) and to link 86 by a pin 98 passing through sides 87, 88, 94 and 95. The shorter portion of sides 94 and 95 are pivotally coupled between bracket 76 and the end of piston rod 73. It will then be apparent that extension of piston rod 73 will result in the lower end of link 92 being pushed forwardly under pin 97 causing the entire blade 40 and support 30 to be tilted upwardly. In FIG. 2, the cylinder 72, its poston rod 73, and the link members 86 and 92 are shown in the position they occupy when the blade is elevated.
The pistion rod locking means of the present invention is also shown in FIG. 2 to include a cylindrical sleeve 100 adapted to surround the extended piston rod 73. The sleeve 100 is split along its length and is hinged on one side by a hinge 101 while a latch 102 is provided on the other side. Locking sleeve 100 is used as follows: When the blade is elevated (FIG. 2) the locking sleve is opened and folded back about hinge 101. The sleeve is then placed around the piston rod 73 and locked into place by latch 102. When the sleeve is secured in place, the piston rod cannot be retracted, even if a failure occurs in the hydraulic fluid system.
FIG. 3 shows in schematic form the hydraulic and cylinder control system of the present invention. The placement of the operating components in the vehicle is not critical to the present invention, but it is preferred that the reservoir pump and valve components now to be described be mounted under the hood of the car 12 in its engine compartment, on the swivel plate 42 or on the cross member 16 of the subframe assembly.
The hydraulic system includes a tank 105 of hydraulic fluid 106 having inlet and outlet hoses 107 and 108 respectively. A pump P driven by an electric motor M powered by the car's electrical system is coupled to hoses 107 and 108 for supplying and receiving hydraulic fluid from a manifold valve assembly 115.
Valve assembly 115 in turn includes a directional control valve 116 and cross-over relief valve 117 for regulating the horizontal swing of blade 40 and a directional control valve 119 and lock valve 120 for control of the lift system. Hoses 121 and 122 leave the valve assembly swing components and are coupled respectively to hoses 65 and 64 while another fluid hose 123 from the valve lift components is coupled to hose 74. Quick disconnect couplings 128-130 are provided for allowing rapid coupling and uncoupling of the respective hoses between those in the car's engine compartment and those mounted to plow assembly 10 when the hydraulic components are in the engine compartment. See FIG. 1.
Toggle switches 136 and 137 are also included in the system, the toggle switches being mounted on the dash board of the car or at some other interior location where they are readily accessible to the driver. Switch 136 is coupled to the valve swing components by wires 140 and controls the flow of fluid to and from cylinders 60 and 61, while switch 137 is connected to the valve lift components by wires 141 and controls the flow of fluid to cylinder 72.
FIG. 4 shows a second embodiment in which the hydraulic components 105 and the valve assembly 115 are mounted on the swivel plate 42 instead of in the engine compartment. In this embodiment hoses 121 and hose 65 are replaced by a single hose 150; hoses 123 and 74 are replaced by a single hose 151, and hoses 122 and 64 are replaced by a single hose 152. In addition, the quick disconnects 128 and 130 are eliminated. In lieu thereof a quick disconnect 155 is provided for wires 140 and 141 and a further quick disconnect 156 is provided for the power supply electrical cable 160 coupled to the hydraulic pump and motor and to the car's electrical system.
The system shown in FIG. 4 has several advantages over the system shown in FIGS. 1 and 3. First, the manufacturing cost is smaller because the length of hydraulic hose is substantially less and the two electrical disconnects are considerably less expensive than the hydraulic disconnects. Secondly, the installation time for the completed assembly is substantially less because the hydraulic components and hoses do not have to be mounted in the vehicle. The only installation required will be the attachment of the subframe assembly, the placement of the switches 136 and 137 and running two electrical cables to the bumper area of the car. Third, the system shown in FIG. 4 is preferred for those automobiles which do not have sufficient room in the engine compartment. Fourth, the vehicle's weight is lighter during periods when the plow is not attached, thus reducing any negative fuel economy resulting from the use of the plow of the present invention. Fifth, the relatively expensive hydraulic components can be safely stored when the plow is not in use, thus avoiding problems with vandalism and unnecessary exposure to the elements when the plow is not needed.
FIG. 5 shows another alternate embodiment of the present invention in which the hydraulic and valve components 105 and 115 are mounted to the cross bar 16 of the vehicle subframe assembly. In this embodiment hoses 121 and 65 of FIG. 1 are replaced by a single short hose 160; hoses 123 and 74 (FIG. 1) are replaced by a single short hose 161; and hoses 122 and 64 are replaced by a single short hose 162. In addition, the disconnects of FIG. 1 are again replaced by the electrical disconnects 155 and 156 which are for the same services as described in FIG. 4.
The system shown in FIG. 4 has many of the advantages shown in FIG. 5 but has the added advantage of reduced hose length and use for some vehicles where mounting on the plow may be impractical.
Now that the major components of the present invention have been described, its operation will be explained. When cold weather approaches, frame 14 is bolted to the chassis of car 12. It is assumed that the hydraulic components have been mounted on the car or the plow or the subframe assembly and that switches 136 and 137 have beeen installed on the car's dash board and the necessary hydraulic or electrical disconnects have been installed.
When it is desired to use the plow assembly 10 it is connected to the car by merely inserting pins 37 in the two brackets coupling frame 14 to blade support frame 30 and by inserting an additional pin 80 in bracket 79 so that the link member 86 is secured behind bumper 20. The hoses or wires (again depending on which embodiment is used) are then coupled to the disconnects to complete the mounting of assembly 10.
It will be apparent from the foregoing description that toggle switch 137 can be moved by the driver to control the elevation of blade 40 and that toggle switch 136 can be selectively moved to change the horizontal orientation or swing of blade 40.
While the present invention has been described in connection with a single preferred embodiment, it is not to be limited by such description but is to be limited solely by the claims which follow. For example, while the invention has been described in connection with a snow plow, the lift system of the present invention is adaptable for use with bulldozer blades, or other similar types of implements.
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A snow plow especially suitable for use with small vehicles, such as cars, is disclosed. The snow plow features a hydraulic system for controlling movement of the plow from side to side as well as for elevating the plow. The snow plow of the present invention also includes a coupling system which permits the plow to be quickly coupled to the vehicle for snow plowing and quick removal of the plow when the vehicle is to be used for its conventional purposes. The hydraulic system may be mounted either on the plow support frame or to the subframe assembly which is attached to the underside of the car.
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FIELD OF THE INVENTION
The present invention generally relates to an electronic assembly, and more particularly to an electronic assembly with a foldable connector thereof. The invention relates to the copending application having the same title, the same filing date, the same applicants and the same assignee therewith.
DESCRIPTION OF PRIOR ART
As development of an electronic technique, an electronic device becomes lower profile and multifunction. Some consumer products, especially those video/audio products, should be equipped with a lower profile power port and signal port. For example, U.S. Pat. Nos. 6,461,198, 6,038,766, 5,895,294 and TW Pat. 406884 introduce some related art of electrical connectors.
U.S. Pat. No. 6,461,198 (hereinafter refer to U.S. '198) discloses audio connection apparatus. The connection apparatus includes plug and jack assemblies. The jack assembly defines a primary insertion hole and at least a pair of secondary insertion openings disposed laterally therefrom. The jack assembly includes a plurality of first conductive plates disposed in each of the secondary insertion openings. The plug assembly which releasably couples to the jack assembly includes a central shaft for engaging the primary insertion hole of the jack assembly in electrically conductive manner, as well as at least a pair of secondary insertions disposed laterally from the central shaft for respectively engaging the insertion openings of the jack assembly in electrically conductive manner. Each secondary insertion includes a plurality of second conductive plates each configured to contact a first conductive plate in electrically conductive manner. The engagement of the secondary insertions and secondary insertion openings enables the auxiliary transmission of electrical audio signals for supplementing the transmission of electrical audio signals through the engagement of the central shaft and primary insertion hole.
However, the plug assembly of U.S. '198 may be disposed outside of an electronic device, and it may occupy more space and be damaged by exterior environmental conditionals.
Hence, an improved electrical assembly is highly desired to overcome the aforementioned problems.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an electrical connector capable of being retracted in a housing of an electronic assembly.
In order to achieve the object set forth, an electronic assembly in accordance with the present invention comprises a housing having a plurality of walls together defining a receiving space and an outlet defined in one of the walls and in communication to the receiving space; a connector pivotally linked to the housing and projected outward of the housing via the outlet; a locking member mounted to the housing, said locking member including a base portion having a first side and a second side opposite to the first side, a stopper portion formed on the first side and extending into the receiving opening, and a resilient member arranged adjacent to the second side for exerting a resilient force to the base portion; and the connector being pivotal to push the stopper member together with the base portion of the locking member against the resilient member to enter into the receiving space and be locked by the stopper member.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an assembled, perspective view of an electronic assembly, with a plug connector exposed outside of a housing thereof.
FIG. 2 is an assembled, perspective view of the electronic assembly, with the plug connector retracted into the housing.
FIG. 3 is an exploded, perspective view of the electronic assembly;
FIG. 4 is similar to FIG. 3 , but viewed from another aspect;
FIG. 5 is an up shell of the housing of the electronic device;
FIG. 6 is a partially assembled perspective view of the electronic assembly showed in FIG. 1 , with the up shell remove away and the plug connector projecting outside of the housing;
FIG. 7 is a partially assembled perspective view of the electronic assembly showed in FIG. 2 , with the up shell removed away and the plug connector retracted into the housing;
FIG. 8 is a partially assembled perspective view of the electronic assembly showed in FIG. 1 , with the bottom shell removed away and the plug connector retracted into the housing;
FIG. 9 is a partially assembled perspective view of the electronic assembly showed in FIG. 2 , with the bottom shell removed away and the plug connector projecting outside of the housing;
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference will now be made in detail to the preferred embodiment of the present invention.
Referring to FIGS. 1-4 , an electronic assembly 100 comprises an up cover 1 , a printed circuit board (PCB) 2 , a first mating port 3 mounted to the PCB 2 , a second mating port 4 arranged aside the PCB 2 , a rotational member 5 mounted to a front section of the up cover 1 , a locking member 6 , and a bottom cover 7 . The up cover 1 and the bottom cover 7 incorporated a housing for accommodating the aforementioned element members.
Referring to FIGS. 3-8 , the up cover 1 includes a top wall 10 , an arched first side wall 110 connected to a left edge of the top wall 10 , a peripheral wall 112 extending downward from right and back edges of the top wall 10 and further connected to the first side wall 110 . A first vertical wall 130 , a second vertical wall 131 , a third vertical wall 132 and a fourth vertical wall 134 are formed on an inner surface of the top wall 10 and interconnected one another to together form a rectangular shaped receiving area 13 . A first opening 14 is defined in the right side of the peripheral wall 112 and aligns with the receiving area 13 transversally. Two first stoppers 141 are spaced apart one another and align with lateral sections of the first opening 14 , and three second stoppers 142 are spaced arranged and proximate to a low edge of the first opening 14 . A second opening 19 is defined in the back side of the peripheral wall 112 , and a positioning post 12 is arranged aside the second opening 19 . A platform 135 is located in the receiving area 13 and adjacent to the third vertical wall 132 . The first vertical wall 130 is perpendicular to and has same height with the second vertical wall 131 . Two extension portions 1321 extend laterally from ends of the third vertical wall 132 and substantially align with the first stoppers 141 , respectively. Two L-shaped stoppers 136 are accommodated in the receiving area 13 and arranged adjacent to the second vertical wall 131 and the fourth vertical wall 134 , respectively. The platform 135 is disposed adjacent to the L-shaped stopper 136 which is arranged aside the fourth vertical wall 134 .
A slot 18 is recessed downwardly from an up surface of the top wall 10 of the up cover 1 and located above the platform 135 . An rectangular shaped aperture 181 is defined in the middle section of the platform 135 and in communication to the slot 18 . A cylindrical cavity 15 is located in the front segment of the inner side of the top wall 10 , adjacent to the left side of the first side wall 110 . An extension wall 153 is arranged on a top edge of the left side section of the cylindrical cavity 15 and has same height as the first side wall 110 . A transversal connection wall 155 connects a front end of the extension wall 153 with an inner surface of the first side wall 110 . A shaft 151 is located in the central section of the cylindrical cavity 15 . Three positioning members 152 asymmetrically around the shaft 151 , and one of the larger positioning members 152 and two of the smaller positioning members 152 are arranged at two lateral sides of the shaft 151 , respectively. A passage 154 is located between the fourth vertical wall 134 , the extension wall 153 and a back side section of the cylindrical cavity 15 . A depression portion 156 is located in front of the transversal connection wall 155 . A recessing portion 160 is arranged on an another side of the front segment of the inner side of the top wall 10 . An upright wall (or supporting wall) 162 is arranged adjacent to the recessing portion 160 and connected to the fourth vertical wall 134 via an inclined transition wall (not numbered). A first cutout 1620 is defined in a lower section of the upright wall 162 , and the first cutout 1620 has an oblique edge with respect to the transversal direction and a parallel edge with respect to the transversal direction. A third opening 161 is defined in an up section of the front segment of the peripheral wall 112 .
Referring to FIG. 5 , three second positioning holes 171 are spaced from one another and attached to an inner surface of the first side wall 110 . Two third positioning holes 172 are arranged along the side section of the peripheral wall 112 . Furthermore, a number of reinforcement portions 1711 , 1721 are formed on outside of the first and second positioning holes 171 , 172 and connected to the first side wall 110 and the side section of the peripheral wall 112 .
Referring to FIGS. 3 , 4 , the PCB 2 is of L-shaped, and three first holes 21 are disposed in lateral sides thereof and two second holes 23 are defined in one of the longer lateral side. The first holes 21 are arranged proximate to outer edges of the PCB 2 . A Light Emitting Diode (LED) 24 is mounted to the PCB 2 and the LED 24 is used for indicating running status of the electronic device. A cutout 25 is defined in the shorter lateral side of the PCB 2 .
The first mating port 3 has thirty terminals 30 therein, and two positioning posts 31 are formed on a back surface thereof.
The second mating port 4 is a universal serial bus (USB) connector and has four terminals 41 therein. A protrusion portion 42 is formed on a rear section of the bottom surface of the second mating port 4 .
The rotational member 5 includes a first base portion 51 and a second base portion 52 mounted onto the first base portion 51 , with a rear portion of a plug connector 53 sandwiched therebetween. The first base portion 51 has a hollowed and cylindrical shaped engaging part 510 and a rectangular holding part (not numbered) attached to lateral side thereof. The second base portion 52 has a hollowed and cylindrical engaging part 520 and a rectangular holding part (not numbered) attached to lateral side thereof. A handling portion 521 extends forwardly from a front surface of the holding part of the second base portion 52 and is arranged aside the plug connector 53 . The handling portion 521 is utilized for operating or swiveling the connector 53 . A coil spring member 54 is assembled to interior portions of the engaging parts 510 , 520 for providing a biasing function. A passageway 5101 is defined in a lower section of the engaging part 510 of the first base portion 51 and in communication to the interior portions of the engaging parts 510 , 520 . Wires (not shown) extend through the passageway 5101 and are coupled to the plug connector 53 .
The locking member 6 includes a base portion 60 , a resilient member 61 mounted to a first side (a right side) of the base portion 60 , a stopper portion 62 formed on a second side (a left side) of the base portion 60 and opposite to the resilient member 61 , and an operation member including a bar portion 64 parallel to a front surface of the base portion 60 and a neck portion (not numbered) connected the bar portion 64 and the base portion 60 . The base portion 60 defines a mounting slot 601 for retaining the resilient member 61 . The resilient member 61 may be a coil spring member or other types of spring members. The stopper portion 62 has a wedge shaped free end 623 which defines an inclined outward surface 621 .
The electronic assembly 100 further has a switch device 8 which includes two supporters 80 , an operation part 82 and a connection member 81 disposed between the supporters 80 and the operation part 82 . The supporter 80 has a rectangular shaped main portion 801 , a slider portion 803 mounted to an up surface 8012 and capable of sliding thereon, and three rows of soldering tails 802 extending downwardly from the main portion 801 . The operation part 82 includes an ellipse shaped operation part 821 , two juxtaposed engaging portions 823 extending downwardly from a middle section of a bottom surface of the operation part 821 . The engaging portion 823 includes a notch 8231 defined in a middle segment of an outside thereof, a locking part 8232 formed at free end thereof, and a protrusion part 8233 attached to the bottom surface of the operation part 821 . The connection member 81 is made of transparent material and configured to be I-shaped viewed from the lateral side. An aperture 810 is defined in a middle section of the connection member 81 . Ribs 8101 are formed on interior side edges of the aperture 810 . Two cavities 812 are defined in opposite side sections of the aperture 810 and proximate to a left side of the connection member 81 . Two flange portions 813 are respectively attached to lateral ends of the connection member 81 . An upper part of the flange portion 813 is thinner than a lower part of the corresponding flange portion 813 . The cavities 812 are respectively disposed adjacent to the corresponding flange portions 813 .
Referring to FIGS. 3 , 6 - 9 , the bottom cover 7 is substantially same as the up cover 1 , and it has a second side wall 710 and a second peripheral wall 712 which are corresponding to the first side wall 110 and the first peripheral wall 112 . A fourth opening 74 , a fifth opening 79 and a six opening 761 are defined in the second peripheral wall 712 and corresponding to the first opening 14 , the second opening 19 and the third opening 161 in the first peripheral wall 112 . Three second positioning holes 71 are arranged along the second side wall 710 and align with the second positioning posts 171 of the up cover 1 . A third positioning hole 72 is disposed adjacent to the fifth opening 79 and adapted for receiving the first positioning post 12 . A number of bars 73 are formed on an inner surface of a low wall (not numbered), extending along a front-to-back direction and disposed adjacent to the fourth opening 74 . A second cutout 762 is defined in an upper section of an upright wall (not numbered) perpendicular to the six opening 761 . The second cutout 762 is same with the first cutout 1620 , but deeper than the first cutout 1620 . A second stopper 763 is arranged aside the six opening 761 and disposed adjacent to the lateral side of the second peripheral wall 712 .
The soldering tails 802 under the supporters 80 are soldered to the PCB 2 , and the two LEDs 24 disposed between the two supporters 80 . The connection member 81 is mounted to the supporters 80 . The slider portions 803 are respectively disposed in the cavities 812 .
Referring to FIGS. 3-9 , when assemble, positioning posts 31 of the first port 3 are inserted into the second holes 23 of the PCB 2 , and contacts (not shown) of the first port 3 are soldered to the PCB 2 . The terminals 41 of the second port 4 are electrically connected to the PCB 2 via some wires (not shown). The operation part 82 is assembled to the top wall 10 of the up cover 1 , with the operation part 821 accommodated in the slot 18 , the engaging portions 823 extending through the aperture 181 , and the protrusion part 8233 of the engaging portions 823 abutting against the front and rear edges of the aperture 181 . The first positioning posts 12 are inserted into the first holes 21 . The engaging portions 823 further protrude into the aperture 810 , with the locking parts 8232 thereof engaging with the ribs 8101 of the connection member 81 . The switch device 8 is accommodated in the receiving area 13 . The first port 3 is against the second vertical wall 131 and extend into the second opening 19 . The second port 4 is arranged between the first stoppers 141 , against the third vertical wall 132 and extend into the fourth opening 74 .
The rotational member 5 is assembled to the up cover 1 , with the passageway 5101 of the cylindrical engaging part 510 toward the passage 154 to have the wires connected to the plug connector 53 through the passage 154 and soldered to the PCB 2 . The shaft 151 and the positioning members 152 are accommodated in the engaging parts 510 , 520 . The positioning members 152 further interfere with an interior side of the engaging part 510 . The locking member 6 is also mounted to the up cover 7 , with the stopper portion 62 projected into the second cutout 762 , the neck portion extending into the six opening 761 , the bar portion 64 exposed outside of the second peripheral wall 712 , and the resilient member 61 proximate to the second stopper 763 .
The bottom cover 7 is assembled to the up cover 1 , with the second positioning posts 71 inserted into the second positioning holes 171 . Therefore, the rotational member 5 and the locking member 6 are securely arranged between the up cover 1 and the bottom cover 7 .
Referring to the FIGS. 1-2 and 6 - 9 , the spring member 54 is capable of biasing or preloading a force to the rotational member 5 and thus plug connector 53 is exposed outside of the housing and perpendicular thereto. When the electronic device 100 is retracted into the housing, an exterior force exerted onto the base portions 51 , 52 , and the rotational member 5 pivots around the shaft 151 , and the plug connector 53 presses onto the inclined surface 621 of the wedge shaped free end 623 to make the resilient member 61 compressed, and a free end of the plug connector 53 slides excessively inwardly and disposed behind the stopper portion 62 , thus the plug connector 53 is locked by the stopper portion 62 . When the plug connector 53 is used, just push the bar portion 64 moving laterally to make the free end 623 of the stopper portion 62 away from the plug connector 53 , thus the plug connector 53 is exposed outside of the housing via a restore force by the spring member 54 .
It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.
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An electronic assembly ( 100 ) includes a housing having a plurality of walls together defining a receiving space and an outlet defined in one of the walls and in communication to the receiving space; a connector ( 53 ) pivotally linked to the housing and projected outward of the housing via the outlet; a locking member ( 6 ) mounted to the housing, said locking member including a base portion ( 60 ) having a first side and a second side opposite to the first side, a stopper portion ( 62 ) formed on the first side and extending into the receiving opening, and a resilient member ( 61 ) arranged adjacent to the second side for exerting a resilient force to the base portion.
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FIELD OF THE INVENTION
This invention relates to pressure control valves, such as, relay valves, response load valves, three pressure type control valves which are used in the air brake system of a railway car.
BACKGROUND OF THE INVENTION
A relay valve shown and described in Japanese Patent No. 44-27163 is one example of the prior art type of a pressure control valve and will now be explained in greater detail with reference to FIG. 4 of the subject application.
As shown in FIG. 4, an air supply chamber is characterized by numeral 1 while an output chamber is characterized by number 2. An exhaust chamber is illustrated by number 3 and an air supply valve is depicted by number 4. Further, it will be seen that an exhaust valve rod is depicted by numeral 5 and a piston is characterized by numeral 6.
In viewing FIG. 4, it will be observed that the air supply chamber 1 has an air supply passage 7 which is connected to the output chamber 2. A connecting port 8 is connected to a suitable compressed air reservoir via a pipe or conduit 8a. A valve seat 9 circumscribes the air supply passage 7 and projects upwardly from the lower side of the air supply chamber 1.
The output chamber 2 has a connection port 10 which is connected to a brake cylinder or the like, and also has an equalizing passage or hole 12 which is connected to a balance chamber which is disposed above the movable piston 6.
The exhaust chamber 3 is open to the atmosphere via the port 13.
The air supply valve 4 is located in the air supply chamber 1 and the upper reduced portion of it is in the back chamber 14 so that it can slide freely in the vertical direction to open and to close the air supply passage 7. The valve 4 is urged downwardly by a biasing or compression spring 15 which is disposed in the back chamber 14 so that it normally causes the valve 4 to seat on the valve seat 9. As shown in FIG. 4, an equalizing passage or hole 16 is located in the lower wall of the valve 4.
As shown, the exhaust valve rod 5 extends through the output chamber 2, through the exhaust chamber 3, and to the balance chamber 11. The upper flared rim or tip 17 of the exhaust valve rod 5 faces the underside of the air supply valve 4. Thus, the outside diameter of rod 5 is designed so that it forms the air supply passage 7. The rod 5 penetrates the wall dividing chambers 1 and 2 and slides freely there between but is air tight by suitable sealing rings. The enlarged piston portion 6 is located at the lower end of rod 5. The rod 5 has a central internal exhaust passageway 18 which extends from upper open end of the tip portion 17 to an opening formed at the other end leading to the exhaust chamber 3.
An enlarged main part 6a of piston 6 has a flange shape portion formed on the lower end of the exhaust valve rod 5. The inner edge of a resilient diaphragm 19 is attached on the outer periphery of the piston main part. The outer edge of the diaphragm 19 extends outwardly and is fixedly attached to the inner surface of the inside wall of the main body of the valve. The upper side of the piston 6 and diaphragm 19 form the above-mentioned balance chamber 11 and the lower side defines a command chamber 20. There is a return spring 21 in control chamber 20 which pushes the piston 6 toward the balance chamber 11. The control chamber 20 has a connection port 22 which connects to an air control supply exhaust pipe 22a.
In this pressure control valve, the condition shown in FIG. 4 is in an overlap state. In the overlap state, the upper tip 17 of the exhaust valve rod 5 is in intimate contact with the air supply valve 4 while the air supply valve 4 is seated on the valve seat 9. In other words, it is the condition in which the output chamber 2 is blocked off from the air supply chamber 1 and also in which the output chamber 2 is blocked off from the exhaust chamber 3.
In this overlap condition, the control force with which the control air pressure P1 in the control chamber 20 pushes the piston 6 upwardly is P2×S1, and the balance force with which the output air pressure P2 in the output chamber 2 pushes the piston 6 downwardly is P2×S2. The above-mentioned S1 is the effective area of the lower surface of the piston 6 and diaphragm on which the control pressure P1 in the air chamber acts, and S2 is the effective area of the upper surface of the piston 6 and diaphragm 119 on which the output air pressure P2 acts. When the force exerted by the return spring is F, the following equation is valid:
P2×S2+F=P1×S1
Since F is small, the output air pressure can be described by the following equation:
P2=(S1/S2)×P1
In other words, the output air pressure P2 is the product of the control air pressure P1 and the effective area ratio of both sides of piston 6.
In this overlap condition, when the control air pressure P1 decreases, the control force becomes less than the balance force, and the piston 6 moves downwardly so that the tip 17 of the exhaust valve rod 5 is unseated from the air supply valve 4, the output chamber 2 connects to the exhaust chamber 3 via the exhaust opening 18. Thus, the output air pressure P2 decreases as a result of this exhausted condition so that the balance force decreases. Now when the balance force is equal to the control force, the valve returns to the overlap condition again. When the control air pressure P1 is reduced to atmospheric pressure, the output air pressure P2 is also reduced to atmospheric pressure.
In addition, in the overlap condition illustrated in FIG. 4, when the control air pressure P1 is increased, the control force becomes greater than the balance force, and the exhaust valve rod 5 pushes the air supply valve 4 upwardly to unseat it from the valve seat 9. In this manner, the air is supplied from the air supply chamber 1 to the output chamber 2 through the air supply passage 7. As a result of this air supply motion, the output air pressure P2 rises and the balance force also increases. When the balance force increases and is equal to the control force, it returns to the overlap condition.
Thus, in the pressure control valve illustrated in FIG. 4, the control air pressure P1 is changed so that a corresponding output air pressure P2 can be obtained. The output air pressure P2 may be used, for example, to operate a vehicle brake system.
In the pressure control valve of FIG. 4, there is only one piston 6 which is separated into a control piston on which the control air pressure P1 acts and which operates as a balance piston on which the output air pressure P2 acts.
The pressure control valve of FIG. 4 is designed so that the ratio of S1/S2 in equation P2=(S1/S2)×P1 becomes constant. However, the characteristic of the output air pressure P2 to the control air pressure P1 may be changed depending on the type of air brake system. In other words, one in which the effective area ratio S1/S2 of the piston is different as required. In such a case, it can be managed by changing one of the effective areas S1, S2 in the pressure control valve of FIG. 4, but in reality, it is very inconvenient to change the design and to have to manufacture it individually for each particular application.
The prior art includes another method to change the effective area ratio of S1/S2, namely the one illustrated in FIG. 4 of the Japanese utility Model No. 61-2119. In this latter arrangement, there is an equivalent to the above-mentioned piston 6 which takes the form of the balance piston and the control piston, and a lever mechanism consisting of the lever and the fulcrum roller is placed between the two pistons, and there is a method to adjust the position of the fulcrum roller. In this structure, the lever ratio can be changed by changing the position of the fulcrum roller so that the size of the force transmitted changes, and, it therefore achieves practically the same result as in the case which the effective area ratio are changed.
In the latter mentioned pressure control valve, the structure of which includes the lever mechanism, the characteristic of the output air pressure P2 to the control air pressure P1 can be changed by adjusting the position of the fulcrum roller. However, the member in the axial direction of the piston provided between the lever and the piston is inclined slightly due to the rotation of the lever during the operation. Thus, it becomes difficult to transmit the work force precisely, and/or the part which affects the function, such as the part of that member which contacts the lever. Namely, the contacting part of the fulcrum roller and the lever tends to become worn so that even if the fulcrum roller is placed at the same position, the output air pressure to the defined control air pressure will be different from the original initial pressure. Thus, after it has been in use for a long time a decrease in sensitivity and response is a problem.
OBJECTS AND SUMMARY OF THE INVENTION
Therefore, it is the object of this invention to make it possible to change the ratio of the effective area of two pistons without using the lever mechanism and without changing the control piston and the balance piston.
In the pressure control valve in which the piston of the pressure control valve of the prior art, as explained in FIG. 4, is formed by the control piston and the balance piston. The invention achieves its object in that there are an air supply chamber, an air supply hole, a valve seat and an air supply valve in a middle body. This middle body can be moved relative to the exhaust valve rod and also it can be fixed at any desired position. The opposite side of the control air pressure or the output air pressure of at least one piston of the two pistons is set at a pressure value which is lower than a minimum supply air pressure value. A plurality of first movable fins are arranged and fixed around the main body of the piston on the side of the lower pressure with its upper edges facing a flexible diaphragm carried by the piston. A plurality of second fixed fins interleaved with the plurality of the first fins are arranged and fixed inside the valve main body. The first fins and the second fins are located between each other and the second fins have upper edges which are on the same side of the diaphragm and are adapted to cross over one another.
In this invention, when the position of the middle body is changed, the position of the valve seat of the middle body also changes. Therefore, the position of the exhaust valve rod changes when it assumes the overlap position in which the air supply valve is seated on the valve seat, and the valve tip of the exhaust valve rod is engaging the air supply valve. The change in the position of this exhaust valve rod changes the position of the control piston main body and the balance piston main body which move together in a unitary manner.
A first slanted surface and a second slanted surface cross one another means so that at least one of the surfaces is not in contact with a surface which is perpendicular to the direction of movement of both pistons, so that the condition in which the diaphragm receives the air pressure and is pushed toward the first surface and the second surface and changes as a function of the position of the control piston main body or the balance piston main body. This change results in the modification of the effective pressure area of the control piston and/or the balance piston.
Consequently, when the position of the middle body is changed the effective area of at least one position in the overlap state is changed so that the effective area ratio of both pistons changes.
In accordance with the present invention there is provided a railway car pressure control valve comprising, an adjustable middle body member having an air supply chamber, an air supply valve and a valve seat, the air supply chamber is connected to a source of compressed air, an output chamber is connectable to an output passage, an exhaust chamber is opened to the atmosphere, the valve seat located in an air supply passage connects the air supply chamber to the output chamber, the air supply valve is biased by a spring toward the valve seat, an exhaust valve rod having a valve tip which faces the air supply valve and fits loosely in the air supply passage and having an exhaust passage which has one end open at the valve tip and which has the other end open to the exhaust chamber, a control piston having a center portion attached to an inner periphery of a control piston diaphragm, the control piston diaphragm having an outer periphery fixed to the inside wall of a valve main body for defining a control chamber, a source of control air pressure connected to the control chamber to provide a pressure force to move the exhaust valve rod in the direction of the air supply valve, a balance piston having a center portion attached to an inner periphery of a balance piston diaphragm, the balance piston diaphragm having an outer periphery fixed to the inside wall of the valve main body for defining a balance chamber which receives the air pressure from the output chamber proving a balancing force to resist the pressure force of the control chamber.
DESCRIPTION OF THE DRAWINGS
The above objects and other attendant features and advantages will be more readily appreciated as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:
FIG. 1 is a vertical cross-sectional frontal view showing the details of the valve structure of a first embodiment of the present invention.
FIG. 2 is a partial cross-sectional view taken along line A--A of FIG. 1.
FIG. 3 is a partial vertical cross-sectional frontal view of a second embodiment of this invention.
FIG. 4 is a schematic vertical cross-sectional frontal view illustrating one embodiment of prior art relay valve.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, and in particular to FIGS. 1 and 2, there is shown a first embodiment which will be presently explained. The pressure control valve shown in the FIGS. 1 and 2 includes a middle body member 31 and a piston element 32 located in the valve main body 30. In FIG. 1, there is shown an air supply chamber 41, an output chamber 42, an exhaust chamber 43, an air supply valve 44, an exhaust valve rod 45, a balance piston 46, and a control piston 47.
The external shape of the middle body member 31 is that of a short cylinder. The short middle body 31 is sealingly fitted into an inner hole 48 formed in the upper part of the valve main body 30 as shown in FIG. 1. It will be appreciated that the body 31 can move up and down or in the vertical direction. The air supply chamber 41 is located in the lower end of the middle body 31. A valve seat 50 controls the flow of fluid through the air supply passage 49 which is adapted to open and close the lower end of the air supply chamber 41. The movable air supply valve 44 is located inside the air supply chamber 41. The valve 44 is urged downwardly to a closed position by a compression or biasing spring 51 so that it normally is seated on the valve seat 50. The air supply chamber 41 is always connected to the pressure air source through an inlet passage 52 which is formed in the side of the valve main body 30. The air supply valve 44 is equipped with a central passage 54 which connects a back chamber 53 which is located in the upper end thereof. The lower end of the passage 54 is located in the vicinity of the air supply passage 49.
The outlet chamber 42 is located on the underside of the middle body 31. The output chamber 42 is connected to the brake cylinder of the vehicle brake system via a passage 55 which is formed in the side of the valve main body 30. A passage 56 forms a fluid path which connects the output chamber 42 and an upper chamber located above the middle body 31, namely, the upper most space which is part of the inner hole 48. Alternatively, the upper space of the inner hole 48 can be vented to the atmosphere so that the passage 56 may be omitted.
As shown in FIG. 1, an adjustable screw 57 and a return biasing spring 58 engage the upper and lower ends of the middle body 31 for adjusting the position and fastening the middle body 31. The adjusting screw 57 extends through a threaded opening formed in the top end of the valve main body 30. The screw 57 has an outer turnable head portion and an inner tip portion which contacts the upper surface of the middle body 31. The compression return spring 58 is caged between the upper part of a main piston 32 and the underside of the middle body 31. The rotation of the screw 57 adjusts the tension of the return spring 58 and causes the middle body 31 to be moved to the desired position.
The piston 32 is disposed in the inner opening 59 formed in the lower portion of the valve main body 30. The piston 32 consists of the balance piston main body 60 which is integrally connected to the lower end of the exhaust valve rod 45. The piston includes a control piston main body 61 and a diaphragm 62 forming the balance piston and a diaphragm 63 of the control piston having first fin 64 and second fin 65 as shown in FIGS. 1 and 2.
The upper rim or seat tip 66 of the exhaust valve rod 45 faces the air supply valve 44 and projects from the underside of the output chamber 42. The outside diameter of tip 66 is substantially equal to the inside diameter of the back chamber 53 of the air supply valve 44. An internal exhaust passage 67 is formed in the rod 45. One end of the exhaust hole 67 opens to the tip 66 while the other end opens to the exhaust chamber 43 via a passage formed in the piston part 32.
The balance piston main body 60 and the control piston main body 61 are formed by a lower section 68 which is contiguous with the exhaust valve rod 45. Thus, these piston members move together with the exhaust valve rod 45. The direction of movement is vertical as is viewed in FIG. 1. The lower part 68 of the exhaust valve rod 45 fits in the lower part of the inner hole 48 forming the valve main body 30 so that it slides freely therein. The inner peripheral edge of the diaphragm 62 is fixedly attached to the circumference of the balance piston main body 60 while the outer peripheral edge is fixedly attached to the wall of the inner opening 59 of the valve main body 30. The inner edge of the diaphragm 63 is connected to the lower portion of the control piston main body 61 while the outer edge is fixed to the wall of the inner opening 59 of the valve main body 30. The diaphragms 62 and 63 are both fabricated of a suitable flexible material. By employing the two diaphragms 62 and 63, the inner opening 59 is divided into an upper balance chamber 69, the intermediate exhaust chamber 43 and a lower control chamber 70. The balance chamber 69 is connected to the output chamber 42 via an opening 71. The exhaust chamber 43 has an exhaust passageway 72 which is formed in the wall of the valve main body 30. The control chamber 70 has a control passage 73 which leads to a source of control air pressure. As shown, the passageway 73 extends through the wall of the valve main body 30. In viewing FIGS. 1 and 2 there are a number of first radial fin members 64 formed on the inside of the exhaust chamber 43 which are integrally formed on the balance piston main body 60. The fins 64 take the form of a star-shaped arrangement as shown in FIG. 2. Each of the fins have their outer edges in close proximity to the inner surface of the inner opening 59. The upper edges 74 of the fins adjacent the diaphragm 62 form a straight line surface which is inclined downwardly and outwardly as viewed in FIG. 1. A number of second radial fin members 65 extend from the wall of the inner opening 59 of the valve main body 30. The second fins 65 are interposed between each of the first fins 64 and the upper edges 75 adjacent the diaphragm 62 to form a straight surface which inclines downwardly and inwardly. The inclined surface which connects the edges 74 of the first fins 64 and the inclined surface which connects the edges 75 of the second fins 65 are crossed between the balance piston main body 60 and the wall of the inner hole 59. The intersection line forms a concentric circle with the balance piston main body 60, and the diameter of the circle of the intersection line changes by the movement of the said piston main body 60 in the axial direction.
A pressure control valve is designed in such a manner that the area S1 is the effective area of the control piston 47 consisting of the control piston main body 61 and the diaphragm 63 then area S2 is the effective area of the balance piston 46 consisting of the balance piston main body 60 and the diaphragm 62. When a control air pressure P1 acts on the control chamber 70 and it assumes the overlapped state as shown in the drawings, and accordingly the output air pressure P2 in the output chamber 42 can be indicated as follows:
P2=(S1/S2)×P1
which is the same as the prior art. Here, the effective area S2 of the balance piston 46 is the surface area where the cross-section of the tip 66 of the exhaust valve rod 45 is subtracted from the area which is inside the circle of the above-mentioned intersection line. That is because, inside the circle of the above-mentioned intersection line, the diaphragm 62 is touching the first fin 64 which is protruding from the balance piston main body 60 so that the work force by the pressure in the balance chamber 69 is transmitted to the balance piston main body 60 inside this circle. However, it is in contact with the second fin 65 which protrudes from the valve main body 30 outside said circle, and the work force of the pressure in the balance chamber 69 is transmitted to the side of the valve main body 30 and does not extend to the balance piston main body 60.
In this pressure control valve, the effective area S2 of the balance piston 46 can be varied by changing the position of the middle body 31. In other words, changing the position of the middle body 31 can be done by moving it vertically by rotating the screw 57. For example, if it is moved upward, it moves while maintaining the state in which the middle body 31 is still in contact with the lower end of the screw 57 by the action of the return spring 58. If the position of the middle body 31 changes as indicated by the imaginary line 31a in FIG. 1 in order to reach the overlapped state, the tip 66 of the exhaust valve rod 45 rises so that the balance piston main body 60 and the control piston main body 61 which are one body with the exhaust valve rod 45 also rise. Therefore, in the overlapped state after changing the position of the middle body 31, the diameter of the intersection line related to the effective area S2 of the above-mentioned balance piston 46, increases compared with that before, and the effective area S2' becomes larger than the previous effective area S2. The dashed line 64a in FIG. 1 indicates the position of the first fin in the overlapped state after the position of the middle body has been changed.
This change of the effective area of the balance piston from S2 to S2' is the change of the above-mentioned effective area ratio from S1/S2 to S1/S2' so that the characteristic of the output air pressure P2 to the control air pressure P1 can be changed.
The first embodiment shows the one in which the upper edges 74 and 75 on the side of the diaphragm 62 corresponding to the first fin 64 and the second fin 65 are inclined in the direction of the extending fin. However, it is apparent that one of the upper edges 74 or 75 of the fins can be horizontal, namely, in the direction perpendicular to the axial line of the piston. In other words, in either cases, the effective area of the balance piston 46 in the overlapped state is changed by changing the position of the middle body 31, and the effective area ratio of the control piston 47 and the balance piston 46 will be changed or varied.
In addition, although the first embodiment is the structure in which there is a fin to the balance piston main body 60 and the side of the valve main body 30 which faces the balance piston main body, instead of this, there can be a fin which is equivalent to the first fin 64 and the second fin 65 on the side of the control piston 47. In the same way, the effective area ratio of the control piston 47 and the balance piston 46 can be changed. However, when there is more than one control air pressure chamber, namely, one on both sides of the control piston 47 when the control piston 47 is constructed in multiples, the different control air pressures work separately. In addition, it assumes the overlapped position in the balanced form to the total control force, for example, in the case where it is applied to the three pressure type control valve as illustrated in FIG. 1 of Japanese Patent No. 59-19866. Also, when it is applied to the multi-level relay valve as illustrated in FIG. 6 of Japanese Patent No. 62-33106. Therefore, the structure of the first embodiment is more appropriately employed.
The following is an explanation of the second embodiment with reference to the accompanying FIG. 3. The main difference of this second embodiment from the first embodiment is the fact that the first fin 79 is provided on both the balance piston main body 60 and the control piston main body 61. In addition, there is a second fin 80 corresponding to the first fin 79. The upper edges 81 and 82 are situated adjacent the balance piston diaphragm 62 while the lower edges are situated adjacent the control piston diaphragm 63. Thus, the first fin 79 and the second fin 80 face the respective diaphragms and are in contact therewith.
The cross sectional shape of the first and second fins 79 and 80, perpendicular to the piston axis, is approximately the same as in FIG. 2. The upper edges 81 and 82 of the first and second fins 79 and 80 are adjacent the side of the diaphragm 62 and are sloped down along the extending direction of each fin which is the same as in the first embodiment. However, the lower edges 83 and 84 of the control piston 47 are adjacent the side of the diaphragm 63 and are sloped up along the extending direction of each fin. Thus, the diaphragm 63 is in contact to the lower edges 83 and 84. An additional difference is the fact that the exhaust passage 67 is also connected between the diaphragms 62 and 63 while at the same time it is opened to atmosphere through an opening 16 formed in the bottom end of the valve main body 30. However, the upper portion, which is not shown in the FIG. 3 is the same as shown and disclosed in FIG. 1.
The pressure control valve of the second embodiment can change the effective area ratio of the control piston 47 and the balance piston 46 by changing the position of the middle body 31. In other words, FIG. 3 is indicative of the overlap condition in which the middle body 31 is in the first position in the overlap condition in which the position of the middle body 31 is shifted upwardly to the second position, the diameter of the circle made by the line in which the inclined surface which connects the upper edge 81 of the first fin by the diaphragm 62 of the balance piston 46 and the inclined surface which connects the upper edge 82 of the second fin 82 intersects is larger than that shown in FIG. 3. The diameter of the circle made by the line in which the inclined surface which engages the lower edge 83 to the first fin by the diaphragm 63 of the control piston 47, and the inclined surface which engages the lower edge 84 of the second fin intersects is smaller than that shown in FIG. 3. Therefore, the effective area of the balance piston 46 changes from S2 to S2' which is larger than S2, and the effective area of the control piston 47 changes from S1 to S1' which is smaller than S1, so that the effective area ratio changes from S1/S2 to S1'/S2'.
In this second example also, one of the upper edges 81 or 82 of the fin, or one of the lower edges 83 or 84 can be perpendicular to the piston axis.
As described above, by means of this invention, the position of the balance piston and the control piston in the overlap condition to the valve main body can be changed merely by changing the position of the middle body. The relative position of the first fin and the second fin is changed by this manipulation. Thus, the effective area ratio of the control piston and the balance piston can be varied. Therefore, the characteristic of the output air pressure to the control air pressure can be changed without replacing the piston as was the case in the prior art. Further, the lever mechanism which causes problems over a long period of operation may be omitted. Compared to the technique of the prior art, in particular the arrangement which uses the lever mechanism, the pressure control valve of this invention uniquely employs the control force and the balance force which oppose each other on the same axis so that the balance piston and the control piston are placed on the same axis. Thus, the problem associated with the lever mechanism namely, the fact that a force other than in the axial direction acts on the piston can be solved.
In addition, the control valve of this invention can be used without any problem in a three pressure control valve, multi-level control valve, load-dependent valve as a pressure control valve in the pneumatic brake system of a railway car. The following is a nomenclature list of components or elements shown and disclosed in the drawings and specifications of the subject invention:
31.--middle body member,
59.--inner opening,
60.--balance piston main body,
61.--control piston main body,
62.--diaphragm of the balance piston,
63.--diaphragm of the control piston,
64.--first fin,
65.--second fin,
66.--valve tip,
67.--exhaust passage,
69.--balance chamber,
--control chamber,
72.--exhaust passage,
73.--control passage,
74.--upper edge of the first fin,
75.--upper edge of the second fin,
79.--first fin,
80.--second fin,
81,83.--upper and lower edges of the first fin,
82,84.--upper and lower edges of the second fin,
Thus, the present invention has been described in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains to make and use the same, and having set forth the best mode contemplated of carrying out this invention. I state that the subject matter, which I regard as being my invention, is particularly pointed out and distinctly asserted in what is claimed. It will be understood that variations, modifications, equivalents and substitutions for components of the above specifically-described embodiment of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims.
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A pressure control valve for railway vehicles having a variable control mechanism for adjusting the gain of the output pressure to input pressure by controlling the effective area ratio on opposite sides of a piston. A balance diaphragm disposed on one side of the piston and a control diaphragm disposed on the other side of the piston. A plurality of first radial fins carried by the piston and a plurality of second radial fins carried by the body of the control valve. The ends of the first fins are placed between the ends of the second fins so that the edges form a slant surface. Thus, at least one of the diaphragms is supported by the slanted surface of the first and second fins. A manual adjusting mechanism for varying the position of the piston of the valve for changing the ratio of the effective areas.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to PCT/EP2014/053197 filed Feb. 19, 2014, which claims priority to EP Application No. 13155823.1 filed Feb. 19, 2013, both of which are hereby incorporated in their entireties.
TECHNICAL FIELD
[0002] The invention refers to a method for operating a gas turbine with staged and/or sequential combustion. Additionally, the invention refers to a gas turbine for implementing the method for operating a gas turbine with staged and/or sequential combustion.
BACKGROUND
[0003] Due to increased power generation by unsteady renewable sources (e.g. wind, solar), existing GT-based power plants are increasingly used to balance power demand and grid stability, thus improved operational flexibility is required. This implies that GT power plants are often operated at lower load than the base load design point, i.e. at lower combustor inlet and firing temperatures. Below certain limits, this reduces flame stability and burnout, with increased CO emissions production.
[0004] At the same time, emissions limit values and overall emission permits are becoming more stringent, so that is required to:
Operate at lower emission values; Keep low emissions also at part load operation and during transient operation, as these also count for cumulative emission limits.
[0007] Combustion systems according to the state of the art are designed to cope with certain variability in operating conditions, e.g. by adjusting the compressor inlet mass flow or controlling the fuel split among different burners, fuel stages or combustors. A goal with this respect is given in gas turbines with staged or sequential combustion concept, as the possibility of operating the first and the second stage or combustor at different firing temperatures already allows an optimization of operation over wider load ranges.
[0008] From EP 0 646 704 A1 arises a method for controlling a gas turbine plant essentially comprising a compressor unit ( 1 ), a high-pressure combustion chamber ( 4 ), a high-pressure turbine ( 6 ), a low-pressure combustion chamber ( 9 ), a lowpressure turbine ( 12 ) and a generator ( 14 ), the quantity of fuel (FH) for the highpressure combustion chamber ( 4 ) is adjusted by a corrected temperature signal composed of the value of the temperature (T 13 ) at the outlet of the low-pressure turbine ( 12 ) reduced by the respective temperature rise (DELTA T) detectable there. This temperature signal (T 13 -DELTA T) is recorded by subtracting the temperature rise (DELTA T) produced by the quantity of fuel (FL) introduced into the low-pressure combustion chamber ( 9 ) from the temperature measured at the outlet of the low-pressure turbine ( 12 ). For the quantity of fuel (FL) for the lowpressure combustion chamber ( 9 ), the uncorrected temperature signal at the outlet of the low-pressure turbine ( 12 ) is used.
[0009] The invention according to EP 0 646 705 A1 proposes a method for providing partial load operation in a turbine plant. This gas turbine plant essentially comprises a compressor unit ( 1 ), an HP combustion chamber ( 4 ) arranged downstream of the compressor unit ( 1 ), an HP turbine ( 5 ) arranged downstream of this HP combustion chamber ( 4 ), an LP combustion chamber ( 8 ) which is arranged downstream of this HP turbine ( 5 ), operates by self-ignition and the hot gases of which act on an LP turbine ( 11 ). Reducing the quantity of fuel in the LP combustion chamber ( 8 ) to zero keeps the temperature at the outlet of the HP turbine ( 5 ) essentially constant. During the lowering of the quantity of fuel in the LP combustion chamber ( 8 ), the quantity of fuel for the HP combustion chamber ( 4 ) furthermore remains approximately constant and the temperature at the inlet to the HP turbine ( 5 ) thus likewise remains constant.
[0010] The gas turbine with respect to EP 0 718 470 A2 consists of a compressor ( 1 ), first and second combustion chambers ( 4 , 8 ) with corresponding high and low pressure turbines ( 6 , 10 ), and at least one generator ( 13 ). Part load operation of the gas turbine is achieved by adjusting the compressor lead vanes to reach loads of below 50 percent of nominal load. During adjustment, the high pressure turbine inlet temperature remains constant while the low pressure turbine inlet temperature falls continuously. The low pressure turbine outlet temperature remains constant. For loads below those achieved using vane adjustment, first the low pressure then the high pressure turbine inlet temperatures are reduced.
[0011] From EP 0 921 292 A1 arises a method for regulation a gas turbo-generator set operated with sequential combustion, in which the fuel quantity necessary for operating the first combustion chamber is first controlled as a function of a pressure prevailing at the outlet of the compressor. The ratio between this fuel quantity and this pressure is continuously updated by means of a factor reproducing the deviation of a temperature at the inlet into the first turbine from the desired value of this temperature. A fuel quantity necessary for operating the second combustion chamber is controlled as a function of a pressure prevailing at the inlet into the second turbine, and the ratio between this fuel quantity and this pressure is likewise continually updated by means of a factor reproducing the deviation of the inlet temperature into the second turbine from the desired value of this temperature. The inertias in the system are neutralized by means of this pressure backup regulation.
[0012] Moreover, CO emissions of gas turbine engines need reduction for the sake of protecting the environment. Such emissions are known to occur when there is not sufficient time in the combustion chamber to ensure the CO to CO 2 oxidation, and/or this oxidation is locally quenched due to contact with cold regions in the combustor. Since the combustor inlet and/or firing temperatures are smaller under part load conditions, the CO to CO 2 oxidation gets slower, thus CO emissions usually tend to increase under these conditions.
[0013] A reduction of CO emissions in turn might be exploited by lowering the gas turbine load at the parking point of a gas turbine. This reduces the environmental impact due to reduced CO 2 (and in some cases other pollutants) emissions and the overall cost of electricity due to less fuel consumption during engine parking. Finally the CO emission reduction might be invested in a reduction of first costs due to savings on a CO catalyst. In this case a CO catalyst might be avoided (or at least reduced). At the same time losses, which appear due a catalyst, will be removed (or at least reduced), and thereby the overall efficiency of the power plant increased.
[0014] According to the US 2012/0017601 A1 the basic of this state of art is a method for operating the gas turbine, which keeps the air ratio λ of the operating burner of the second combustor below a maximum air ratio λ max during part load operation. This method is characterized essentially by three new elements and also by supplementing measures which can be implemented individually or in combination.
[0015] The maximum air ratio λ max in this case depends upon the CO emission limits which are to be observed, upon the design of the burner and of the combustor, and also upon the operating conditions, that is to say especially the burner inlet temperature.
[0016] The first element is a change in the principle of operation of the row of variable compressor inlet guide vanes, which allows the second combustor to be put into operation only at higher part load. Starting from no-load operation, the row of variable compressor inlet guide vanes is already opened while only the first combustor is in operation. This allows loading up to a higher relative load before the second combustor has to be put in operation. If the row of variable compressor inlet guide vanes is opened and the hot gas temperature or turbine inlet temperature of the high-pressure turbine has reached a limit, the second combustor is supplied with fuel.
[0017] In addition, the row of variable compressor inlet guide vanes is quickly closed. Closing of the row of variable compressor inlet guide vanes at constant turbine inlet temperature TIT of the high-pressure turbine, without countermeasures, would lead to a significant reduction of the relative power.
[0018] In order to avoid this power reduction, the fuel mass flow, which is introduced into the second combustor, can be increased. The minimum load at which the second combustor is put into operation and the minimum fuel flow into the second combustor are therefore significantly increased.
[0019] As a result, the minimum hot gas temperature of the second combustor is also increased, which reduces the air ratio λ and therefore reduces the CO emissions.
[0020] The second element for reducing the air ratio λ is a change in the principle of operation by increasing the turbine exhaust temperature of the high-pressure turbine TAT 1 and/or the turbine exhaust temperature of the low-pressure turbine TAT 2 during part load operation. This increase allows opening of the row of variable compressor inlet guide vanes to be shifted to a higher load point.
[0021] Conventionally, the maximum turbine exhaust temperature of the second turbine is determined for the full load case and the gas turbine and possibly the downstream waste heat boiler are designed in accordance with this temperature. This leads to the maximum hot gas temperature of the second turbine not being limited by the TIT 2 (turbine inlet temperature of the second turbine) during part load operation with the row of variable compressor inlet guide vanes closed, but by the TAT 2 (turbine exhaust temperature of the second turbine). Since at part load with at least one row of variable compressor inlet guide vanes closed the mass flow and therefore the pressure ratio across the turbine is reduced, the ratio of turbine inlet temperature to turbine exhaust temperature is also reduced.
SUMMARY
[0022] Prior concepts might not be sufficient to control CO emissions to a given value during the whole part load range due to the limitations in possible firing temperature increase for mechanical integrity reasons.
[0023] The above described limitations are addressed with the present invention by controlling at the same time the number of the burners in operation in the second stage or second combustor and the position of the compressor inlet guide vanes, thereby allowing operation of single burners at sufficiently low air-to-fuel ratio without the need of increasing the turbine operating temperatures.
[0024] Thus, the main technical problem solved by the invention consists in the fact of an improved gas turbine combustion performance at low load with respect to CO emissions, stable combustion, and combustion efficiency for sequential engines, allowing increased operational flexibility.
[0025] When de-loading a gas turbine, like for example a sequential combustion gas turbine known as GT24/GT26 by applicant, and for example according to EP 0 620 362 A1, wherein this document forming integral part of the present description, second stage burners are sequentially switched off individually or in groups, such that the burners remain in operation at the same hot gas temperature as at higher engine load, and thereby maintain in the same low CO emissions. According to the proposed method the TAT-strike (maximum local turbine outlet temperature) is kept unchanged, which results in a reduced TAT 2 (average turbine outlet temperature of the second turbine) because the turbine outlet temperature is locally reduced downstream of the burners, which are switched off. In order to maintain a sufficient hot gas temperature downstream of the burner in operation the VIGV (variable inlet guide vane) of the compressor is adjusted. For deloading a burner or burners are switched of and the VIGV can be opened at the same time in order to keep the same power output. For loading a burner or burners are switched on and the VIGV can be closed at the same time in order to keep the same power output. In case a burner has to be switched off for a slightly reduced load set point, the fuel mass flow would be controlled to be lower, because of the local hot gas temperature limitation and the load would drop consequently. This is compensated with opening the VIGV to adjust the load to the commanded set point. By opening the VIGV the intake mass flow increases, thus allowing an increase in fuel mass flow to the active burners. Further, the pressure ratio over the second turbine is increased, thereby increasing the hot gas temperature of the remaining operative burners for unchanged TAT-strike (loading is carried out analogous with reversed order).
[0026] Based on these findings the concept can be applied to an engine, which runs under sequential combustion (with or without a high pressure turbine) in an annular and/or can-architecture.
[0027] Referring to a sequential combustion the combination of combustors can be disposed as follows:
[0028] At least one combustor is configured as a can-architecture, with at least one operating turbine.
[0029] Both, the first and second combustors are configured as sequential can-can architecture, with at least one operating turbine.
[0030] The first combustor is configured as an annular combustion chamber and the second combustor is built-on as a can configuration, with at least one operating turbine.
[0031] The first combustor is configured as a can-architecture and the second combustor is configured as an annular combustion chamber, with at least one operating turbine.
[0032] Both, the first and second combustor are configured as annular combustion chambers, with at least one operating turbine.
[0033] Both, the first and second combustor are configured as annular combustion chambers, with an intermediate operating turbine.
[0034] In addition to the method, a gas turbine for implementing the method is a subject of the invention. Depending upon the chosen method or combination of methods, the design of the gas turbine has to be adapted and/or the fuel distribution system and air system have to be adapted in order to ensure the feasibility of the method.
[0035] Especially, also manufacturing tolerances leads to different pressure losses and flow rates during operation. The tolerances are selected so that they have practically no influence upon the operating behavior during normal operation, especially at high part load and full load. At part load with high air ratio λ, the combustor can, however, is operated under conditions in which even small disturbances can is have a significant influence upon the CO emissions.
[0036] The process can be carried out according to different embodiments. A first embodiment uses the average measured exhaust temperature TAT 2 .
1. Process in transient state with control of the TAT 2 (the average measured exhaust temperature of the low pressure turbine): 1.1 Gas turbine is de-loaded until CO limit is reached. 1.2 Individual burners of the second combustor, respectively the second stage, are switched off to reduce load. Switching off a burner leads to a redistribution of the fuel flow to the remaining burners in operation with consequently increased local hot gas temperature. Additionally the difference between the highest TAT 2 reading and the arithmetic average increases. With constant fuel flow the load would remain about constant. 1.3 With a schedule for the average TAT 2 limit or a control of the TAT 2 limit using the measured TAT-strike or a margin from the measured TAT-strike to a maximum allowable TAT-strike the local hot gas temperatures after the burner in operation is controlled to a target temperature. The TAT 2 limit schedule can for example be based on relative load, or the number of burner in operation. Due to the change in TAT 2 limit the fuel mass flow is reduced, and consequently the power is reduced. 1.4 To reach the target load the actual load is finally adjusted with the inlet guide vanes and leads to the intended CO emission reduction as described in the previous section. When opening the inlet guide vanes the TAT 2 decreases. The fuel flow can be increased again to increase the power to the target load.
[0042] With two parameters, TAT 2 limit schedule or TAT 2 limit control and number of burner switched off, the CO emissions and the hot gas temperature limits can be adjusted for every load point.
[0043] A second embodiment uses the average measured maximum local exhaust temperature (TAT-strike).
2. Process with control of maximum local exhaust temperature: 2.1 Ata low load of the gas turbine, the CO limit is reached. 2.2 A burner of the second combustor or combustion stage is switched off to reduce CO by redistributing the fuel which was previously injected to the switched off burner to the remaining active burners thereby recovering the local hot gas temperature. 2.3 If a TAT 2 _strike (local measured maximum exhaust temperature of the second turbine) is increased beyond a maximum allowable value the controller reduces fuel mass flow by lowering the average TAT 2 set point. Due to the lowered fuel mass flow the power is reduced. 2.4 The target load is finally adjusted with the inlet guide vanes and leads to the intended CO emission reduction as described in the previous section. When opening the inlet guide vanes the TAT 2 decreases. The fuel flow can be increased again to increase the power TAT 2 -strike can be used in case of switched off burners equivalently to the use of the TAT 2 limit. In contrast to the disclosed method the TAT 2 limit was kept constant for lower loads in the prior art. The number of burner in operation is used to control CO emissions and can be adjusted for every load point.
[0049] Furthermore, the method of operation in accordance with the invention refers to the location of the burners to be switched and is defined based on the identification of the burner, which produce the highest CO emissions and single outlet temperature reading from the first or second combustor, under custody of measurement of the local emissions points.
[0050] The advantages of the invention are as follows:
The operating range of the gas turbine can be extended to lower load points for a given CO emission limit. CO emission can be reduced at low load points to the power plant air permit limit. No lifetime penalty due to increased TAT-strike. No limitation regarding operation time or load gradient in this lower load range. Burners which are main responsible of CO production (e.g. split line burners) can be targeted and switched off first, giving a maximum benefit. The process can be controlled in closed-loop for optimized emissions and lifetime. In order to avoid too frequent burner switching when load is varying the burner valves are switched on or off with a hysteresis.
[0058] The advantages associated with this invention are as follows:
[0059] CO emissions are reduced especially at lower part-load conditions. Therefore, the gas turbine power plant can support the grid with an increased power range. Additionally the gas turbine can be parked at lower loads during periods, where low power output is targeted by the power plant operator.
With the increased load range the power plant will be more often called to support the grid, because load flexibility is getting more important with increasing contribution of renewable power. The power plant can be parked at lower loads in periods of low power demand leading to lower fuel consumption and overall reduced cost of electricity. Environmental benefit due to reduced CO emissions, lower parking point (thus less fuel consumption and CO 2 production) or a combination of both advantages. Possibility of eliminating an expensive CO catalyst. Therefore first costs are reduced.
[0064] When using a setup including dilution air switching/variation between the cornbustor cans further advantages arise:
Further CO reduction, with all advantages described above, due to increased volume for CO oxidation with origin in the first combustor. Reduction of circumferential temperature gradients between the different can combustors. Therefore the turbine inlet profile is improved and lifetime of turbine parts is improved.
[0067] Control logic for defined CO and maximum turbine outlet temperatures control as a function of relative load, number of burner in operation or constant parameter like TAT-strike forming integral part of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] The invention is shown in FIGS. 1 to 3 based on exemplary embodiments:
[0069] FIG. 1 schematically shows a gas turbine with sequential combustion for implementing the method according to the invention;
[0070] FIG. 2 schematically shows a cross section of the second combustor with burners;
[0071] FIG. 3 schematically shows an operational concept with burner switching and temperature and VIGV control.
DETAILED DESCRIPTION
[0072] FIG. 1 schematically shows a gas turbine with sequential combustion for implementing the method according to the invention. It comprises a compressor 1 , a first combustor 4 ′ comprising a number of burners 9 and a combustion chamber 4 , a first turbine 7 , a second combustion chamber 15 ′ comprising a number of burners 9 ′ and combustion chamber 15 , and a second turbine 12 . Typically, it includes a generator 19 which at the cold end of the gas turbine, that is to say at the compressor 1 , and is coupled to a shaft 18 of the gas turbine. The first cornbustor 4 ′ and the second combustor 15 ′ can be an annular architecture or a can architecture, while the first turbine 7 is optional.
[0073] The can architecture comprises a plurality of burners with subsequent cans arranged in an annular array about the circumference of the turbine shaft, which enables an individual combustion operation of each can 4 , 15 , and which will cause no harmful interactions among individual cans during the combustion process.
[0074] The annular architecture comprises a plurality of burners arranged in an annular array about the circumference of the turbine shaft, with subsequent annular combustion chambers 4 , 15 which facilitates cross ignition between different burners.
[0075] A fuel, gas or oil is introduced via a fuel feed 5 into the burner 4 of the first combustor 4 ′, mixed with air which is compressed in the compressor 1 , and combusted in the combustion chamber 4 . The hot gases 6 are partially expanded in the subsequent first turbine 7 , performing work.
[0076] As soon as the second combustor is in operation, additional fuel, via a fuel feed 10 , is added to the partially expanded gases 8 in burners 9 ′ of the second combustor 15 ′, and combusted in the second combustion chamber 15 . The hot gases 11 are expanded in the subsequent second turbine 12 , performing work. The exhaust gases 13 can be beneficially fed to a waste heat boiler of a combined cycle power plant or to another waste heat application.
[0077] For controlling the intake mass flow, the compressor 1 has at least one row of variable compressor inlet guide vanes 14 .
[0078] As an additional option, in order to be able to increase the temperature of the intake air 2 , provision can be made for an anti-icing line 26 through which some of the compressed air 3 can be added to the intake air 2 . For control, provision is made for an anti-icing control valve 25 . This is usually engaged on cold days with high relative air moisture in the ambient air in order to forestall a risk of icing of the compressor 1 .
[0079] In this example some of the compressed air 3 is tapped off as high-pressure cooling air 22 , re-cooled via a high-pressure cooling air cooler 35 and fed as cooling air 22 to the first combustor 4 ′ (cooling air line is not shown) and to the first turbine.
[0080] The mass flow of the high-pressure cooling air 22 , which is fed to the highpressure turbine 7 , can be controlled by means of a high-pressure cooling air control valve 21 in the example.
[0081] Some of the high-pressure cooling air 22 is fed as so-called carrier air 24 to the burner lances of the burners 9 ′ of annular combustion chamber 15 of the second combustor 15 ′. The mass flow of carrier air 24 can be controlled by means of a carrier-air control valve 17 .
[0082] Some of the air is tapped off, partially compressed, from the compressor 1 , recooled via a low-pressure cooling air cooler 36 and fed as cooling air 23 to the combustion chamber 15 of the second combustor 15 ′ and to the second turbine. As a further option the mass flow of cooling air 23 can be controlled by means of a cooling-air control valve 16 in the example.
[0083] One or more of the combustors can be constructed as annular combustors, for example, with a large number of individual burners 9 resp. 9 ′, as is generic shown in FIG. 2 by way of example of the second combustor. Each of these burners 9 resp. 9 ′ is supplied with fuel via a fuel distribution system and a fuel feed 10 , figuratively in accordance with FIG. 2 .
[0084] FIG. 2 shows a section through for example the second combustion chamber 15 ′ as an annular combustion chamber of a gas turbine with sequential combustion, is and also the fuel distribution system with a fuel ring main 30 to the individual burners 9 ′. The same fuel distribution is possible with respect to a second combustion chamber 15 comprising of cans. The burners 9 ′are provided with individual on/off valves 37 for deactivating each burner 9 ′ for controlling the fuel flow in the fuel feeds 10 to the respective burner of 9 , 9 ′ of the first and second combustor 4 ′, 15 ′.
[0085] By closing individual on/off valves 37 , the fuel feed to individual burners 9 ′ of the annular combustion chamber 15 (or to the burners of every can) is stopped and optional the fuel can be distributed to the remaining burners 9 ′, wherein the overall fuel mass flow is controlled via a control valve 28 . As a result, the air ratio λ of the burners 9 in operation is reduced.
[0086] Item 20 shows the external housing of the gas turbine including a stator arrangement (not shown) in connection with the compressor and turbines
[0087] FIG. 3 shows an operational concept with burner switch/off and temperature and VIGV control, in relation to the conventional process (indicated as original). When de-loading the gas turbine, single second stage burners 100 are sequentially switched off, in the manner that the remaining burners 100 operate at the same hot gas temperature as at higher engine load, thereby maintaining the same low CO emissions.
[0088] With respect to the original standard operation concept, the TAT 2 _avg 300 was reduced in order to keep the local maximum local turbine outlet temperatures TAT 2 _strike 200 constant, as long as they correlate with the highest burner hot gas temperatures.
[0089] This is achieved by opening VIGV 400 at the same time in order to keep the same power output.
[0090] The curves shown in FIG. 3 with respect to original method and new operational method according to the invention are considered qualitatively. The different shape of the curves ( 100 - 400 ) is schematic, and forms the basis for achieving the objectives of the invention.
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The invention concerns a method of operating a gas turbine with staged and/or sequential combustion. The burners of a second stage or a second combustor are singularly and sequentially switched on during loading and switched off during de-loading. The total fuel mass flow and the compressor inlet guide vanes are adjusted at the same time to allow controlling gas turbine operation temperatures and engine power with respect to the required CO emission target.
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This application claims priority to U.S. Provisional Patent Application Ser. No. 61/639,949 filed Apr. 29, 2012.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to cementing equipment used with oilfield wellhead equipment and, in particular aspects, to couplings that are useful for such equipment.
2. Description of the Related Art
After a hydrocarbon wellbore has been drilled, a casing is typically cemented in along the length of the drilled bore. Cementing equipment is used to do this and typically includes a top drive cement head that permits balls or rubber darts to be dropped into the wellbore during the cementing operation. The cement head also must be capable of flowing cement from a cement supply downwardly into the wellbore. Suitable cementing equipment for these purposes includes a top drive cement head which is available commercially from Baker Hughes Incorporated of Houston, Tex.
SUMMARY OF THE INVENTION
The invention provides methods and devices for quickly connecting and disconnecting a conduit to a port. In a described embodiment, a quick connect coupling is described for quickly connecting and disconnecting a cement supply conduit to the port of a top drive cement swivel. An exemplary quick connect coupling includes a stinger assembly that is reversibly coupled to a breech lock box connector on the cement swivel. Raised keys on the breech lock barrel will interfit with complimentary ridges with a bore of the breech lock connector.
In certain embodiments, a locking arrangement that secures the stinger assembly against rotation within the breech lock connector. In one embodiment, a locking pin is used to lock the stinger assembly into place and against rotation with respect to the cement swivel. An exemplary locking pin is described that is retained by the cement swivel and is axially moveable between unlocked and locked positions. In the locked position, the locking pin will reside within a complimentary indentation within the stinger assembly thereby preventing rotation.
In operation, a user can quickly and easily couple the stinger assembly with the cement swivel easily and without the need for hammers and other tools to be used. A crane may be used to lift and move the stinger assembly and affixed cement conduit to a position that is proximate the breech lock box connector of the cement swivel. An operator can then orient the stinger assembly so that the keys of the stinger assembly are angularly offset from the ridges within the bore. The stinger and breech lock barrel are then inserted into the bore. Thereafter, the user rotates the stinger assembly to align the keys of the stinger assembly with the ridges of the bore. When aligned, each of the keys are preferably located in line with and behind a ridge, preventing the stinger assembly from being withdrawn from the breech lock connector. The locking arrangement is then engaged to lock the stinger assembly in place so that it cannot be rotated with the breech lock connector.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and further aspects of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference characters designate like or similar elements throughout the several figures of the drawing and wherein:
FIG. 1 is a side view of portions of an exemplary wellbore cementing operation.
FIG. 2 is an isometric view of an exemplary stinger assembly in accordance with the present invention.
FIG. 3 is a side view of the stinger assembly shown in FIG. 2 .
FIG. 4 is a cross-sectional view taken along lines 4 - 4 in FIG. 3 .
FIG. 5 is a front view of an exemplary cement swivel with stinger assembly attached in accordance with the present invention.
FIG. 6 is a cross-sectional view taken along lines 6 - 6 in FIG. 5 .
FIG. 7 is a front view of the cement swivel and stinger assembly depicting the stinger assembly being coupled to the swivel.
FIG. 8 is an enlarged cross-sectional view of portions of an exemplary coupling in accordance with the present invention.
FIG. 9 is a side view of the exemplary cement swivel and stinger assembly shown in an unlocked condition.
FIG. 10 is a side view of the cement swivel and stinger assembly of FIG. 9 , now in a locked condition.
FIG. 11 is a cross-sectional view, partially in phantom, showing portions of the stinger assembly and cement swivel in an unsecured condition.
FIG. 12 is a cross-sectional view, partially in phantom, showing portions of the stinger assembly and cement swivel now in a secured condition.
FIG. 13 is an isometric view of an exemplary breech lock barrel shown apart from other components of the coupling.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates portions an exemplary cementing operation for a wellbore. A tubular working string 10 extends downwardly into a wellhead 12 . A cementing tool 14 is incorporated into the working string 10 which typically contains balls and/or plugs which are launched into the working string 10 during a cementing operation. A top drive cement swivel 16 is affixed to the upper end of the cementing tool 14 . The cement swivel 16 operates to receive cement and transmit it through a flowpath in the cementing tool 14 so that the cement can be flowed downwardly into the working string 10 . FIG. 1 also depicts a cement hose 18 with an affixed stinger assembly 20 . Cement can be flowed to the cement swivel 16 when the stinger assembly 20 is coupled to the cement swivel 16 . The cement hose 18 and stinger assembly 20 are depicted being lifted by block and tackle 22 .
The structure and operation of an exemplary stinger assembly 20 are better appreciated with further reference to FIGS. 2-4 . The stinger assembly 20 includes a curved rigid pipe portion 24 that is affixed to the hose 18 . A flange 26 with lifting eye 28 extends upwardly from the pipe portion 24 . A stinger 30 extends outwardly from the pipe portion 24 . A cement flow path 32 is defined within the pipe portion 24 and stinger 30 . A breech lock barrel 34 radially surrounds the stinger 30 and, as can be seen best in FIGS. 4 and 8 , secured to the stinger 30 by a sleeve 36 that preferably permits the breech lock barrel 34 to rotate about the stinger 30 . FIG. 13 shows the breech lock barrel 34 apart from the other components of the stinger assembly 20 . A flange 38 projects radially outwardly from the breech lock barrel 34 and presents at least one indentation 40 . In the depicted embodiment, there are six indentations 40 . In preferred embodiments, an enlarged grippable handle 42 also radially surrounds the stinger 30 and is secured by bolts 44 ( FIG. 2 ) to the breech lock barrel 34 so that the stinger 30 will be rotated when the handle 42 is rotated.
The outer radial surface of the breech lock barrel 34 preferably presents a plurality of raised keys 46 . As will be appreciated with regard to FIGS. 2 , 3 , 4 and 8 , the keys 46 are organized into rows (A, B and C) and perpendicular columns. The keys 46 are spaced apart from each other along each of the rows A, B and C and each of the columns. In some embodiments, there are six keys 46 per row A, B and C spaced angularly from each other at about 30 degrees apart. In certain embodiments, the breech lock barrel 34 also includes a row of raised anti-rotation locking dogs 47 . In the depicted embodiment, there are six locking dogs 47 that are positioned in a spaced relation from one another of about 30 degrees apart.
The structure of the exemplary top drive cement swivel 16 is better understood with reference to FIGS. 5-10 . It can be seen that the cement swivel 16 has a generally box-shaped main housing 50 . A central axial flowbore 52 passes vertically through the main housing 50 . Lateral fluid flow openings 54 , 56 extend through the main housing 50 and permit fluid communication between the central flowbore 52 and the exterior of the cement swivel 16 . A tubular breech lock box connector 58 extends outwardly from the main housing 50 . As illustrated in FIGS. 11 and 12 , the breech lock box connector 58 defines an interior bore 60 having a plurality of inwardly projecting ridges 62 . The ridges 62 are spaced apart from each other both radially and axially within the bore 60 . Preferably, the interior bore 60 also includes an annular fluid seal 63 ( FIG. 8 ) that creates a fluid seal against the stinger 30 when it is inserted into the bore 60 . In addition, the interior bore 60 also presents a row of inwardly projecting anti-rotation locking dogs 48 . The dogs 48 are meant to be complimentary to the anti-rotation dogs 47 of the breech lock barrel 34 .
FIGS. 9 and 10 illustrate a locking pin 64 which is preferably used with the cement swivel 16 and is used to lock the stinger assembly 20 into a coupled position with respect to the cement swivel 16 . The locking pin 64 is preferably retained by a sleeve 66 and is axially shiftable between two positions. In the unlocked position shown in FIG. 9 , the locking pin 64 does not prevent rotation of the stinger assembly 20 with respect to the cement swivel 16 . In the locked position shown in FIG. 10 , the locking pin 64 is disposed within an indentation 40 of the flange 38 and will prevent rotation of the stinger assembly 20 with respect to the cement swivel 16 . In particular embodiments, the locking pin 64 has a handle portion 68 that can be used to rotate and shift the locking pin 64 between the unlocked and locked positions.
In operation, a user can rapidly couple or uncouple the cement conduit 18 to the cement swivel 16 . In order to couple the stinger assembly 20 to the cement swivel 16 , the block and tackle 22 is used to lift and move the stinger assembly 20 by lifting eye 28 until the stinger assembly 20 is proximate the breech lock connector 58 of the cement swivel 16 . A user can then grasp the handle 42 of the stinger assembly 20 and rotate the stinger assembly 20 to the approximate position shown in FIG. 7 . In FIG. 7 , the stinger assembly 20 is rotated approximately 30 degrees from the vertical, as illustrated in FIG. 7 . This rotation will align the keys 46 of the stinger assembly 20 angularly between the ridges 62 of the breech lock barrel bore 60 so that the breech lock barrel 34 can be fully inserted into the bore 60 , as illustrated in FIG. 11 . Once fully inserted, the user will rotate the stinger assembly 20 approximately 30 degrees back to the position depicted in FIG. 5 . This rotation will move the raised keys 46 of the breech lock barrel 34 to the position illustrated in FIG. 12 , wherein each key 46 is located behind a ridge 62 within the bore 60 . Also, each row A, B and C of keys 46 is located behind a row of ridges 62 . The locking dogs 47 will radially abut the dogs 48 of the bore 60 (as depicted in FIG. 12 ), preventing further rotation beyond 30 degrees. In this position, the stinger assembly 20 cannot be axially withdrawn from the bore 60 . The stinger assembly 20 is now coupled to the cement swivel 16 . The user can now move the locking pin 64 from the unlocked position ( FIG. 9 ) to the locked position ( FIG. 10 ) as described previously. Seating of the locking pin 64 within the indentation 40 will prevent the stinger assembly 20 from being inadvertently rotated and uncoupled from the cement swivel 16 . Cement can now be flowed along the cement flow path 32 from the cement conduit 18 into the lateral flow opening 54 of the cement swivel and into the central flowbore 52 of the cement swivel 16 .
In order to uncouple the stinger assembly 20 from the cement swivel 16 , a user will reverse the operations. The locking pin 64 is moved from the locked position ( FIG. 10 ) to the unlocked position ( FIG. 9 ). A user can then rotate the stinger assembly 20 approximately 30 degrees to the position illustrated in FIG. 7 . The stinger assembly 20 can then be axially withdrawn from the bore 60 of the breech lock connector 58 .
The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to those skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention.
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Devices and methods are described for quickly connecting and disconnecting a conduit to a port. A quick connect coupling is described for quickly connecting and disconnecting a cement supply conduit to the port of a top drive cement swivel.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for alignment of individual fibers in a known direction. This method and apparatus are fundamental to the development of the technology for production of fiber-woven garments with qualities like those made from yarn-woven fabrics and offer increased productivity and reduced material waste and energy consumption as compared with conventional processes of spinning staple fibers into yarn, of weaving yarn into fabric, and of tailoring garments from fabrics.
Staple fibers must be arranged in orderly patterns to produce fiber-woven fabrics with aesthetic and performance characteristics comparable to conventional woven fabrics. The fibers in the final fabric are oriented principally in two perpendicular directions so that the fibers retain bending and sliding characteristics similar to those of warp and fill yarns in conventional woven fabric.
The processes of separating, aligning (or paralleling), and depositing the fibers provide the main problems in producing fiber-woven garments. The present invention pertains to the fiber alignment part of the overall process.
2. Description of the Prior Art
Studies have been made of the movement of fibers by air flows for textile-industry related applications, some of which relate to general problems of fiber transport, with others being concerned with particular devices for producing nonwoven fabrics. As such, the same are not concerned at all with fiber alignment, but instead seek to form an isotropic fiber web. The work of Edberg, "A Basic Investigation of the Behavior of Cotton Fibers Subjected to Aerodynamic Forces", Studies in Modern Yarn Production 1968, pp. 96-108, is related to the problems of orienting as well as transporting fibers. In this study, air flows with fibers were observed in straight ducts which had different degrees of convergence, and it was discovered that large percentages of the fibers could be made parallel. To do so, however, required high air speeds (30 to 100 m/sec) which is undesirable for the ordered deposition of the fibers.
The patent to Jakas and Mullin ("Fiber Aligning Apparatus", U.S. Pat. No. 3,619,869, Nov. 1971) describes an apparatus in which fibers move in an accelerating air flow through a cone, and pass out of the cone through a slot and onto a moving screen. The slot width is less than the fiber length, while the slot length is greater than the fiber length. Another patent, by Marshall and Silvi ("Reorientation of Fibers in a Fluid Stream", U.S. Pat. No. 3,812,553, May 1974), also relates to fiber alignment. In this case a high-velocity fluid stream carrying fibers is formed, then decelerated to form a wide but shallow stream, and then deflected by a downward-curving wall. It is stated that this causes the fibers to be oriented in a direction substantially perpendicular to the flow direction. Specific results cited are in terms of the ratio of cross-direction to machine-direction strength of the web.
SUMMARY OF THE INVENTION
The objective of this invention is to provide a method and apparatus which aligns individual fibers parallel to the main stream flow, while maintaining low velocity to provide for orderly deposition of the fibers.
According to the present invention, individual fibers are introduced to a main airflow stream and are subsequently aligned parallel to the main flow stream through the use of fluid-dynamic forces originating from an orientating member. The aligned fibers are then deposited on a surface so that parallel alignment is maintained to form a fiber web for subsequent entanglement or bonding to produce a fiber-woven fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawings in which like reference characters designate like or corresponding parts throughout the several views, and wherein:
FIG. 1 is a schematic perspective view of one embodiment of the invention;
FIG. 2 is a side elevation view of a wind tunnel;
FIG. 3 is a photograph of the test section of the wind tunnel showing a fiber at several points along its path; and
FIG. 4 is a sectional view of another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In general, fibers injected into a fluid stream have a random orientation. Velocity gradients of special types in the fluid stream are required to produce changes in fiber orientation, so that the fibers are turned parallel and then remain so for a sufficiently large distance.
It is very important to have a system that can produce a wide variety of velocity gradients in the flow, in order to deal with different types of fibers and different main stream conditions. This system needs to be flexible, so that changes in the flow conditions can be made rapidly and easily. These considerations have led to a basic system as shown in FIG. 1 which includes a small wind tunnel 1 with counterflow jets 2. The main air stream 4 moves through wind tunnel 1 and, in the absence of counterflow jets 2, the velocity profile at any station is very nearly uniform, except for a thin boundary layer near the walls 5. The velocity profiles of main air stream 4 can be easily changed by changing the counterflow jet velocity U J and/or the counterflow jet angle θ J . The counterflow jets can be directed from 0° (downstream) to 180° (upstream). In the present configuration, each jet tube has an 11/16 inch O.D., with 37 equally-spaced orifices of 3/32 inch diameter. The object of this large number of closely-spaced orifices is to produce a flow which is two-dimensional.
As shown in FIG. 2, wind tunnel 1 includes a primary air source 6, header pipe 8, pressure regulator 10 with reducing coupling and, supply pipe 14 which connects to the transition portion 16 of the wind tunnel. The transition portion 16 also connects to diffusor 18 which conveys the main air stream to a plenum 20 which is provided with damping screens 22. Air flow passes through contraction cone 24 prior to entering the wind tunnel cross-sectional area at which counterflow jets 2 and counterflow air injection tubes 26, which are supplied with air under pressure through secondary air source 30, operate. The main air stream then continues through the wind tunnel to a test section 32 containing a deposition screen 34 to form a fiber web with the air flow continuing on to exhaust 36.
The introduction of individual fibers into the main stream 4 flow upstream of counterflow jets 2 can be accomplished in a variety of ways. The purpose of diffusor 18, plenum 20, and contraction cone 24 is to provide a uniform, irrotational flow at the entrance to test section 32. The action of counterflow jets 2 modifies this flow, by producing a rather rapid convergence of main stream 4, followed by a rather slow divergence. The resulting velocity gradients tend to produce fiber alignment parallel to the main stream direction. Deposition surface 34 is to be placed less than one test section height h downstream of counterflow jets 2, as experiments have shown that fiber alignment occurs within this distance.
A fiber injector 38 is provided upstream of said deposition surface. The first part of the process is to obtain individual fibers from slivers containing many thousands of fibers. This can be done in a variety of ways known to current textile industry practice. For example, a slowly-rotating feed roller can be used to feed a sliver to a high-speed, toothed, opening roller which pulls individual fibers from the sliver. These individual fibers can be carried away by arranging for a suitable air flow through the apparatus. The fibers are introduced into the wind-tunnel about one-half to one test-section height h upstream of the jets. Once the individual fibers are moving in an air stream, they must be aligned, which is the subject of this invention. After alignment, the fibers are deposited on a deposition surface 34 to form a fiber web. The final step is fiber entanglement or bonding to produce a fabric (not shown).
Either natural or synthetic fibers may be carried by the main air stream 4 and aligned parallel to the air flow direction, as described above. The fibers are then deposited on deposition surface 34 placed in the air flow, such as a screen, and during deposition the fibers retain their alignment. By a similar fiber alignment process, fibers may be aligned in a direction perpendicular to the first and be deposited on deposition surface 34. The result is a loose web of fibers on deposition surface 34 aligned in two perpendicular directions. The two perpendicular directions of fiber alignment can be achieved with a single air flow system by suitably reorienting deposition surface 34 during the deposition process. Alternatively, two separate air flow systems depositing fibers on a surface of fixed orientation could be used. After the fiber web has been formed, the fibers are entangled or bonded using an existing process. The result is a fabric which has the desirable characteristics associated with fiber alignment in two perpendicular directions as previously noted.
The principal data on the fiber motion are multiflash photographs of the fiber trajectory as typified by FIG. 3. This photograph shows the fiber at several points along its path and was made using a stroboscopic light source (not shown), with the room darkened.
The basic concept of fiber orientation using the counterflow jets is as follows. Upstream of counterflow jets 2, the fiber is in a uniform flow, and its orientation does not change because this flow is essentially irrotational. The jets produce an effective nozzle wall for main stream 4, so that the streamlines converge toward the center of the test section and the flow accelerates. Downstream of the jets, the central irrotational core decelerates, and its streamlines remain nearly parallel to the test section centerline.
A fiber that is parallel to the mainflow streamlines upstream of counterflow jets 2 remains so throughout, and continues parallel to the duct centerline downstream of the jets. A fiber that is initially at an angle relative to the mainflow streamlines is rotated to a parallel orientation by the streamline convergence near jets 2. The streamlines nearer to walls 5 are accelerated toward the centerline, so that a resultant moment is applied to a fiber that lies across the streamlines. This moment goes to zero when the fiber becomes parallel to the streamlines, so the fibers retain their parallel orientation downstream of the jets in this still nearly irrotational flow.
The nondimensional parameters that govern the fiber motion are as follows:
(1) x c /h and y c /h, the position (x c ) of fiber release upstream of the jets and above (y c ) the lower wall of the test section, respectively, are shown in FIG. 1. Again, h is the height of the test section.
(2) m.sub.∞ /m j , the ratio of main stream flow rate to jet flow rate.
(3) θ j , the counterflow jet angle.
(4) φ o , the initial fiber angle relative to the main stream. (For appropriate combinations of the other parameters, the fibers become parallel to the test section centerline, independent of φ o ).
(5) l f /d f , the ratio of fiber length to diameter.
(6) ρ f /ρ.sub.∞, the ratio of fiber density to main stream air density.
(7) l f /h, the ratio of fiber length to test-section height.
(8) ρ.sub.∞ U.sub.∞ 2 /ρ f d f g, the ratio of aerodynamic lift force on the fiber to the gravitational force. This parameter is a measure of how rapidly the fiber drops toward the lower wall of the test section. U.sub.∞ is the velocity of the main stream flow which, for most experiments was 20 ft/sec.
(9) ρ.sub.∞ U.sub.∞ d f /μ.sub.∞, the Reynolds number.
These parameters have been varied in experiments performed to demonstrate the concepts described previously. From the results that have been obtained, it may be concluded that the basic principles of operation of the system to produce parallel fiber orientation have been demonstrated.
EXAMPLE 1
As shown in FIG. 3, the values of the above-noted parameters were as follows:
(1) x c /h=-0.5 (x c =0 at the counterflow jets. Thus, the fibers were released one-half test section height upstream of the jets).
y.sub.c /h=0.6
m.sub.∞ /m.sub.j =37 (2)
θ.sub.j =90° (3)
φ o =120° (4)
l.sub.f /d.sub.f =420 (5)
ρ.sub.f /ρ.sub.∞ =1290 (6)
l.sub.f /h=0.0833 (7)
ρ.sub.∞ U.sub.∞.sup.2 /ρ.sub.f d.sub.f g=48 (8)
ρ.sub.∞ U.sub.∞ d.sub.f /μ.sub.∞ =24 (9)
The above values of these parameters are typical for the experiments performed, but successful operation is not restricted to these values.
The fiber alignment occurs in a very short distance (less than one foot), while maintaining a low air stream velocity (25 ft/sec or less). The use of counterflow jets 2 to achieve the desired velocity gradients provides great flexibility for the system, because changes in flow conditions can be made rapidly and easily. This is important when dealing with changes in fiber geometry and properties, and also allows greater flexibility in the choice of main stream flow conditions.
It is also possible to provide the required velocity gradients by a second embodiment using suitably designed impermeable or semi-permeable solid boundaries 38 as shown in FIG. 4. A particular geometry of this type might then serve to replace the counterflow jets for a particular jet flow rate and jet angle. Such arrangement makes use of the same basic principle of fiber alignment described previously.
FIG. 4 shows a theoretical body shape which roughly approximates the effect of the jets on the mainstream flow. Here, x/h=0 corresponds approximately to the location of the jets. In the first embodiment, the jets produced a rather rapid contraction of the mainstream, followed by a rather slow divergence. In the second embodiment, an equivalent solid body produces a similar behavior in the mainstream.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
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A method and apparatus are provided for aligning individual fibers parallel to the main fluid stream that is conveying them, using fluid-dynamic forces. This method and apparatus are based on the use of converging streamlines in a nearly irrotational flow to provide the necessary moments to rotate the fibers so that they become parallel to the streamlines. Counterflow jets are provided to create the desired streamline behavior in a main fluid stream. The irrotationality of the flow and the nearly parallel streamlines thus prevent further fiber rotation downstream.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of copending International Application No. PCT/DE00/00026, filed Jan. 3, 2000, which designated the United States.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a read/write architecture for a magnetoresistive random access memory (MRAM) addressable via word lines and bit lines. The MRAM has a multiplicity of ferromagnetic memory elements that are disposed at crossovers between word lines and bit lines. The memory elements at the crossovers form rows and columns of a matrix, which furthermore each contain two ferromagnetic layers separated by a separating layer, and whose resistance perpendicular to the layer sequence is in each case higher than that of the word lines and of the bit lines and depends on the magnetization state of the ferromagnetic layers.
[0004] As is known, MRAMS are non-volatile random access memories which, in comparison with other types of non-volatile and also volatile memories such as, for example, DRAMs, FRAMS (ferroelectric RAMs), EEPROMS (electrically erasable and programmable ROMs or read-only memories) and FLASH memories, are distinguished by advantages such as, in particular, high storage densities ranging into the order of magnitude of 100 Gbits/chip or more, simple process architectures and hence low fabrication costs per bit.
[0005] The cell arrays of MRAMS expediently contain metallic word lines and bit lines, also called write lines and read lines, which are disposed in a matrix-like manner and are disposed one above the other such that they respectively run in the x-direction and y-direction in a Cartesian xy coordinate system, and between which the ferromagnetic memory elements are provided at the crossovers between the word lines and the bit lines. The ferromagnetic memory elements contain at least two ferromagnetic layers that lie one above the other and are magnetically decoupled, which is effected by a separating layer provided between the ferromagnetic layers. The separating layer may be a tunneling barrier made, for example, of aluminum oxide (Al 2 O 3 ) or a non-ferromagnetic conductive layer made, for example, of copper.
[0006] The ferromagnetic layers are composed, for example, of iron, cobalt, nickel, permalloy (NiFe), etc., it being possible for them to contain additions such as platinum, for example, which promote a finely crystalline state.
[0007] The ferromagnetic layers may have a layer thickness of between 3 and 20 nm, while the separating layer located between them may have a thickness of 1 to 3 nm.
[0008] The ferromagnetic layers of each memory element have switching fields of different magnitude and can therefore be subjected to magnetization reversal independently of one another by switching currents in the word lines and bit lines, which form interconnects. In this case, the resistors of the individual memory elements have resistances dependent on the relative magnetization of the ferromagnetic layers that form them. If both ferromagnetic layers are magnetized parallel to one another, then the memory element has a resistance R 0 , while a resistance R 0 +ΔR (ΔR>0) is present in the case of antiparallel magnetization of the two ferromagnetic layers. The ratio ΔR/R 0 is about 0.1 . . . 0.2. This effect is referred to as the magnetoresistance effect. The term magnetoresistive memory elements is also customary for the ferromagnetic memory elements.
[0009] These two resistances of the ferromagnetic layers, that is to say the resistance R 0 for parallel magnetization and the resistance R 0 +ΔR for the antiparallel magnetization, can be assigned the quantities “0” and “1” of binary memories.
[0010] Writing to MRAMs is simple, in principle, if the fact that the requisite switching field strengths have to be achieved by the interconnects is disregarded. It has proved more difficult for the information stored as resistances in the memory elements to be read out reliably and as simply as possible, that is to say without the assistance of selection transistors, which enlarge the memory cell areas and make the fabrication process more complex.
[0011] Various efforts have already been made to configure the read-out securely and reliably without selection transistors. A principal problem in reading the memory cells disposed in high memory density with a cell area of 4 F 2 (F=minimum feature size) is that each memory cell, that is say each resistive element whose resistance is to be determined, is “shunted” through a multiplicity of parallel current paths, which makes it problematic to determine the resistance exactly, especially in large memory cell arrays.
[0012] In order to overcome these difficulties, two read-out methods have previously been disclosed for MRAMS.
[0013] In the first method, the word lines and the bit lines are electrically insulated from one another, and the read current flows through a relatively small number, for example ten, of memory elements connected in series. The resistance of a relevant memory element can then be inferred from the change in the read current by a relatively complex circuit (in this respect, see the reference by D. D. Tang, P. K. Wang, V. S. Speriosu, S. Le, R. E. Fontana, S. Rishton, IEDM 95-997).
[0014] The method requires write currents through the two interconnects (word line and bit line) which cross at the relevant memory element. The number of memory elements connected in series is limited by the relative change in the total resistance, which change becomes ever smaller as the number increases, and the measurement of the current change, which measurement becomes more difficult. The small number of memory elements that can be connected in series with one another necessitates a large outlay on circuitry for the periphery of the memory array and thus results in a large area requirement for the read electronics.
[0015] The second read-out method consists in all word lines and bit lines, with the exception of the word line connected to the selected memory cell, being put at “0” potential. A potential not equal to zero is applied to the selected word line, while the selected bit line and all other bit lines are brought to a “virtual” zero potential by using an operational amplifier for current measurement (in this respect, see Published, Non-Prosecuted German Patent Application DE 197 40 942 A1).
[0016] Both methods have the disadvantage that they are based on the determination of the absolute value of the resistance of the individual memory elements, as a result of which very stringent technological requirements are placed on accurate, reproducible and homogeneous setting of the resistances over the entire memory cell array and also over a semiconductor wafer or a plurality of semiconductor wafers. Equally, it must be taken into consideration here that in the case of the relatively small changes of ΔR/R 0 , temperature fluctuations can bring about changes in the resistance which make it more difficult to reliably determine the magnetization states of individual memory elements and hence to read the latter. In addition, in the second method, the finite bit line resistances have the effect that the condition of a virtual zero potential is met only at the ends of the bit lines, with the result that parasitic shunt currents have an adverse effect in the case of long bit lines.
SUMMARY OF THE INVENTION
[0017] It is accordingly an object of the invention to provide a read/write architecture for a MRAM that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which, in conjunction with a simple construction, allows reliable reading of the memory cell array and does not place unrealistically stringent requirements on the exact, reproducible and homogeneous setting of the resistances of the individual memory cells.
[0018] With the foregoing and other objects in view there is provided, in accordance with the invention, a read/write architecture for a magnetoresistive random access memory (MRAM). The read/write architecture contains bit lines, word lines crossing over the bit lines, and a multiplicity of ferromagnetic memory elements disposed at the crossover points of the word lines and the bit lines and forming rows and columns of a matrix. Each of the ferromagnetic memory elements contains a layered sequence having a separating layer and two ferromagnetic layers separated by the separating layer. The ferromagnetic memory elements have a resistance perpendicular to the layer sequence in each case higher than that of the word lines and of the bit lines and depends on a magnetization state of the ferromagnetic layers. The ferromagnetic memory elements are each connected between one of the word lines and one of the bit lines. At least one of the ferromagnetic memory elements functions as a reference memory element having a known magnetization state.
[0019] Connections between the reference memory element and each of the ferromagnetic memory elements defines taps of resistance bridges and a resistance ratio of each of the ferromagnetic memory elements to the reference memory element can be determined by the resistance bridges. Each of the resistance bridges includes the reference memory element and one of the ferromagnetic memory elements.
[0020] In the case of a read/write architecture according to the invention, the object is achieved by virtue of the fact that the ferromagnetic memory elements are each connected between one of the word lines and one of the bit lines, at least one reference memory element has a known magnetization state, and the resistance ratio of each memory element to the reference memory element can be determined by resistance bridges.
[0021] In the case of the read/write architecture according to the invention, then, by use of special external circuitry of the memory cell array, which forms a “resistor grid”, the magnetization state of the individual memory elements, that is to say the parallel or antiparallel magnetization of the ferromagnetic layers, is not determined by absolute measurement of the resistance—the customary procedure hitherto in the prior art—but rather by resistance comparison with memory elements of a known magnetization state. In this case, at least one memory element must be provided as a reference memory element, in which case a whole column and/or a whole row of memory elements may expediently also have a known magnetization state. In this case, such a known magnetization state is, for example, a parallel magnetization of both ferromagnetic layers with the low resistance R 0 or an antiparallel magnetization of the two resistive layers with the resistance R 0 +ΔR (ΔR>0). The known magnetization state should be written in before the actual read process.
[0022] The resistances are compared by resistance bridges, namely half-bridges or full-bridges, which are produced by the abovementioned external circuitry of the resistor grid.
[0023] At the center taps of the resistance bridges, voltages arise which make it possible to infer the relative magnitude of the resistances in the resistance bridges and thus the information stored in the individual memory elements, that is to say “0” 0 (for example parallel magnetization) or “1” (for example antiparallel magnetization).
[0024] With vanishing shunt voltage across the resistance bridges, the resistances correspond and both have the value R 0 , for example. However, if the shunt voltage differs from zero, then the resistance sought has a value that deviates from the resistance of the reference memory element, namely R 0 +ΔR, for example.
[0025] During reading, by way of example, a voltage −V/2 can be applied to the reference memory element, while the voltage +V/2 can then be applied to a memory element to be read.
[0026] The materials for the individual memory elements are the same as has already been mentioned above. The separating layer between the ferromagnetic layers may be composed of, for example Al 2 O 3 (i.e. a barrier layer) or of copper and have a layer thickness of between 1 and 3 nm, while the ferromagnetic layers themselves are constructed in a customary manner from iron, cobalt, nickel, permalloy with corresponding additions (for example platinum) and have a layer thickness of between 3 and 20 nm.
[0027] An advantageous development of the invention provides for current followers or amplifiers to be used for resistance comparison purposes in the individual resistance bridges and for their output voltage to be independent of the number m of word lines in the resistor grid. As a result, it is possible to use large cell arrays, so that the area ratio of the memory cell array to the read-out electronic also increases.
[0028] An essential advantage of the invention is that it enables a large memory cell array with memory cells without selection transistors, even the measurement signal obtained when reading a memory cell being able to be made independent of the size of the memory cell array with the aid of the abovementioned current follower.
[0029] Additional advantages that can be attained by the invention can be summarized as follows. The read-out electronics are constructed comparatively simply and merely have the task of distinguishing between symmetry or asymmetry of the individual resistance bridges. In contrast to the prior art, the measurement signal is completely independent of the absolute value of the individual resistive elements; it merely depends on the voltages applied to the memory cell array and the magnetoresistance effect ΔR/R 0 of the individual memory elements. The technological requirements placed on accuracy, reproducibility and homogeneity in the fabrication of the memory cell array are reduced since reading is based solely on the comparison of resistors that are closely adjacent to one another within the memory cell array. In contrast to the absolute value determination of the resistances which is customary in the case of the prior art, in the case of the read/write architecture according to the invention the measurement signal is used in its full magnitude for distinguishing the two resistance states and is not just contained in a small change in the measurement quantity. Temperature-dictated changes in resistance have no influence on the read signal since they cancel out in the bridge circuit. It is possible to read relatively large memory cell arrays without selection transistors, which results in considerable advantages in respect of storage density, process simplicity and costs per bit. Line resistances of the word lines and of the bit lines are at last partly ineffectual for symmetry reasons.
[0030] Other features which are considered as characteristic for the invention are set forth in the appended claims.
[0031] Although the invention is illustrated and described herein as embodied in a read/write architecture for a MRAM, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
[0032] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] [0033]FIG. 1 is a diagrammatic, perspective view of a memory cell array of a MRAM without selection transistors according to the invention;
[0034] [0034]FIG. 2 is a circuit diagram of the memory cell array in accordance with FIG. 1;
[0035] [0035]FIG. 3 is a circuit diagram of the memory cell array shown in FIG. 2 in the case of a read-out operation;
[0036] [0036]FIG. 4 is a circuit diagram of an electrical circuit of half-bridges when voltages −V/2 and +V/2 are present on word lines;
[0037] [0037]FIG. 5 is a circuit diagram of a circuit of the half-bridges when voltages of −V/2 and +V/2 are present on the bit lines;
[0038] FIGS. 6 to 8 are circuit diagrams of the bridge circuits for elucidating the voltages respectively tapped off at the bridges;
[0039] [0039]FIG. 9 is a circuit diagram of the bridge circuit that is used to elucidate how different logic states can be obtained depending on the resistances;
[0040] [0040]FIG. 10 is a circuit diagram of the bridge circuit with current followers in accordance with a particularly advantageous exemplary embodiment; and
[0041] [0041]FIGS. 11 and 12 are circuit diagrams showing a comparison between the bridge circuit without a current follower (FIG. 11) and the bridge circuit with the current follower (FIG. 12).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case. Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a memory cell array of a magnetoresistive random access memory (MRAM) without selection transistors with so-called “4 F 2 ” memory cells containing ferromagnetic memory elements 1 , word lines WL and bit lines BL. In this case, the memory cells 1 are located at crossovers between the word lines WL and the bit lines BL and each contain ferromagnetic layers 2 , 3 , between which a separating layer 4 is provided. The separating layer 4 may be a tunneling barrier made, for example, of aluminum oxide, or a non-ferromagnetic conductive layer made, for example, of copper.
[0043] The word lines WL and the bit lines BL run in the y-direction and x-direction, respectively, with the result that the memory cells 1 form a matrix-like resistor grid.
[0044] The resistance of the individual memory cells 1 depends on the magnetization directions of the two ferromagnetic layers 2 , 3 . In the case of parallel magnetization of the ferromagnetic layers 2 , 3 with respect to one another, the resistance is small and has a value R 0 , while in the case of antiparallel magnetization of the resistive layers 2 , 3 , the resistance has a magnitude R 0 +ΔR, ΔR>0.
[0045] The word lines WL and the bit lines BL, which form interconnects, may be composed of aluminum, for example. Preferred layer thicknesses for the ferromagnetic layers 2 , 3 are 3 to 20 nm, for example, and for the separating layers 4 are 1 to 3 nm, for example.
[0046] Application of corresponding electric voltages to a specific word line WL and a specific bit line BL enables the ferromagnetic layers 2 , 3 of a memory element 1 located at the crossover point between the word line WL and the bit line BL to be magnetized in a parallel or antiparallel manner.
[0047] A parallel magnetization with low resistance can then be assigned to a logic “0”, for example, while an antiparallel magnetization with high resistance corresponds to a logic “1”.
[0048] [0048]FIG. 2 shows an electrical circuit diagram of the memory cell array shown in FIG. 1, in which case voltages U 1 , U 2 , . . . , U m are present on m word lines WL and voltages U 1 ′, U 2 ′, . . . , U n ′ are present on n bit lines BL. The individual memory cells are illustrated by resistors R 11 , R 21 , . . . , R 12 , R 22 , . . . R ik , . . . , R mn . FIG. 2 shows how the individual memory cells form a resistor grid, the resistances of the individual resistors R ik depending on the magnetization state thereof (parallel magnetization with low resistance or antiparallel magnetization with high resistance).
[0049] A voltage of −V/2 and of +V/2 is then respectively applied to two arbitrary word lines WL, with the result that U i =−V/2 and U k =+V/2 (FIG. 3). A potential “0” is present on the remaining word lines WL. This situation is illustrated in FIG. 3 for the case i=1 and k=2.
[0050] The parallel short circuit of the resistors R 31 , R 41 , . . . , R 32 , R 42 , . . . , R 3k , R 4n , . . . , R mn —at potential “0”—of each bit line BL gives rise to half-bridges, as is illustrated diagrammatically in FIG. 4, in which case the resistor R 1 ′ denotes the resistance of the resistors R 31 , R 41 , . . . , R m1 connected in parallel with one another. The same applies correspondingly to the resistors R 2 ′ and R 3 ′.
[0051] The voltages U 1 ′, U 2 ′, U 3 ′, . . . , U i ′ (i=1, 2, . . . , n) depend on a ratio of the two resistances in each half-bridge: by way of example, if R 11 =R 21 , then U 1 ′=0. If U 1 ′<0, then R 1 ′<R 21 . By contrast U 1 ′>0 is assigned to R 11 >R 21 .
[0052] For the shunt resistors R i ′, across which the voltages U 1 ′, . . . U i ′ are dropped, the following holds true:
R 0 /( m− 2)≦ R i ′≦( R 0 +ΔR )/( m− 2) (1)
[0053] The lower limit R 0 /(m−2) is present if all the resistors R 3i , R 4i , . . . , R mi exhibit a parallel magnetization of the ferromagnetic layers, while the upper limit (R 0 +ΔR/(m−2) is applicable if the resistors are all magnetized in an antiparallel manner.
[0054] Instead of the voltages −V/2 and +V/2 respectively being applied to two word lines WL, it is also possible for two bit lines BL to be connected to the voltages. This case is illustrated diagrammatically in FIG. 5, in which case the voltages U 1 , U 2 , . . . , U i (i=1, 2, . . . , m) then provide information about the resistance ratios R ik /R ik+1 (i=1, 2, . . . , m, k−1 . . . n).
[0055] In this way, it is possible to compare any desired rows or columns with one another.
[0056] When writing to such a MRAM, currents of suitable magnitude are simultaneously sent through a respective word line WL and bit line BL. As a result, the memory element located at the crossover between the word line and the bit line can be transferred to a parallel-magnetized state or antiparallel-magnetized state of its ferromagnetic layers 2 , 3 , which corresponds to a logic “0” or “1”.
[0057] A subsequent read-out then presupposes that, for example, all the memory elements of a word line, such as the first word line with the voltage U i , are transferred to a known magnetization state, that is to say, for example, to a parallel magnetization of the ferromagnetic layers 2 , 3 , but the corresponding resistance R 0 need not be known.
[0058] During reading, the potentials −V/2 and +V/2 are respectively applied to two word lines, for example the first and the second word line with the voltages U 1 and U 2 , respectively, in FIGS. 2 to 4 . The center contact of the voltage source is at zero potential just like the remaining word lines WL 3 to WLm connected to one another with low resistance. Only shunt resistors R i ′ of the resultant half-bridges are formed by the resistors R 3i to R mi (i=1, 2, . . . n) connected to each bit line BL being connected in parallel. The voltages U i ′ (i=1, 2, . . . , n) are dropped across these resistors R i ′, which lie within the interval given above by equation (1), which voltages allow a comparison of the resistors R 2i with the resistors R 1i , as can be shown diagrammatically using FIGS. 6 to 8 .
[0059] FIGS. 6 to 8 show the bridge voltages U i ′ (i=1, . . . , n) for the example of the topmost half-bridge in FIG. 4. The current I through the resistor R 1 ′ (see FIG. 6) results from superposition of the currents I 1 (see FIG. 7) and I 2 (see FIG. 8), which are generated independently of one another by the two voltage sources U 1 and U 2 , in each case the other voltage source being replaced by a short-circuiting bridge (see FIGS. 7 and 8). The current I generates a voltage U 1 ′ across the resistor R 1 ′, which voltage permits comparative statements about the resistances of the resistors R 11 and R 21 .
[0060] In detail, the currents I 1 , I 2 and I are given by:
I 1 = U 1 R 11 + R 1 ′ R 31 R 1 ′ + R 21 R 31 R 1 ′ + R 21 = U 1 R 21 R 11 R 1 ′ + R 11 R 21 + R 1 ′ R 21 ( 2 ) I 2 = U 2 R 11 R 11 R 1 ′ + R 11 R 31 + R 1 ′ R 21 ( 3 ) I = I 1 + I 2 = U 1 R 21 + U 2 R 11 R 11 R 1 ′ + R 11 R 21 + R 1 ′ R 21 ( 4 )
[0061] From this there then follows for the voltage U 1 ′:
U 1 ′ = IR 1 ′ = V 2 R 1 ′ ( R 11 - R 21 ) R 11 R 1 ′ + R 11 R 21 + R 1 ′ R 21 ( 5 )
[0062] For the voltage U 1 ′, the following values are obtained depending on the resistors R 11 and R 21 or the magnetization resistances of the ferromagnetic layers 2 , 3 :
U 1 ′ = { 0 for R 11 ≃ R 21 > 0 for R 11 > R 21 < 0 for R 11 < R 21 ( 6 )
[0063] In general, the following relationships hold true for the comparison of the matrix resistors R ji with the resistors R 1i on the first word line WL 1 :
U i ′ = { 0 for R 1 i ≃ R ji > 0 for R 1 i > R ji < 0 for R 1 i < R ji ( i = 1 … n ; j = 2 … m ) ( 7 )
[0064] After the resistances have been ascertained for the first two word lines, for example by comparators on the bit lines BL, the operation can be successively repeated with further word line pairs, that is to say, for example, the word lines WL 1 and WL 3 , WL 1 and WL 4 , . . . , WL 1 and WLm, until the magnetization states of all the resistors in the matrix have been determined.
[0065] In this case, the following generally holds true for the voltages U i ′:
U i ′ = 1 R 1 ′ = V 2 R i ′ ( R 1 i - R ji ) R 1 i R 1 ′ + R 1 i R 21 + R 1 ′ R ji ( i = 1 … n ; j = 3 … m ) ( 8 )
[0066] With the relationship (1) already mentioned, there follows from this:
V 2 Δ R / R Δ R / R ( m - 1 ) + m ≤ U 1 ′ ≤ V 2 Δ R / R Δ R / R + m ( 9 )
[0067] As an example, for a memory cell array having 1000 bit lines BL (n=1000) and 100 word lines WL (m=100), a magnetoresistance effect ΔR/R 0 =0.2 and voltage sources of 1 V in each case, the following are obtained:
[0068] U i ′=0 for like resistors in the i-th half-bridge,
[0069] U i ′<0 where 1.67 mV≦|U i ′|≦2.00 mV for unlike resistors in the i-th half-bridge independently of the resistance R 0 .
[0070] The loading on the current sources is in this case 1000×10 μA=10 mA for R 0 =100 kohm and 1000×1 μA=1 mA for R 0 =1 Mohm.
[0071] [0071]FIG. 9 shows a case in which the parallel magnetization state of the ferromagnetic layers 2 , 3 with the low resistance R 0 has been written in for all the memory elements of the first word line WL 1 . From vanishing values of the bridge voltages U i ′=0, it then follows that the other resistors of the half-bridges also have the value R 0 . If their value is negative, however, then these resistors have the higher value R 0 +ΔR. The following relationship is thus present:
U 1 ′ = 0 R 21 = R 0 < 0 R 21 = R 0 + Δ R U 2 ′ = 0 R 22 = R 0 < 0 R 33 = R 0 + Δ R U 3 ′ = 0 R 23 = R 0 < 0 R 23 = R 0 + Δ R U j ′ = 0 R 21 = R 0 < 0 R 21 = R 0 + Δ R ( i = 1 … N ) ( 10 )
[0072] In the exemplary embodiments above, the shunt voltages are used to distinguish the small resistance (parallel magnetization) and the large resistance (antiparallel magnetization). In this case, with memory cell arrays having a large number m of word lines and/or n of bit lines, the signals become small approximately proportionally to m (and/or n). In order to avoid this disadvantage, for resistance comparison purposes, current followers are inserted into the individual resistance bridges, the output voltages of which current followers are then independent of the number m of word lines (and/or the number n of bit lines) in the resistor grid.
[0073] This entails the additional advantage that large memory cell arrays can be used, which results in that the area ratio of memory cell array to read-out electronics increases.
[0074] [0074]FIG. 10 shows an exemplary embodiment in which current followers 5 are provided at the outputs of the individual resistance bridges.
[0075] Such current followers make it possible to avoid the disadvantage that the voltage U i ′ tends toward zero if the number of word lines m becomes larger and larger. This relationship will be explained below first with reference to FIG. 11.
[0076] In accordance with equation (5), the following first holds true:
U 1 ′ = 1 R 1 ′ = V 2 R 1 ′ ( R 11 - R 21 ) R 11 R 1 ′ + R 11 R 21 + R 1 ′ R 21 ( 11 )
[0077] With R 11 =R 0 and R 21 =R 0 +ΔR, it follows from this that:
U 1 ′ = V 2 Δ R 2 R 0 + Δ R + ( R 0 + R 21 Δ R ) R 0 / R 1 ′ ( 12 )
[0078] With R 0 /(m−2)≦|R 1 ′|≦(R 0 +ΔR)/(m−2), the following then results:
V 2 Δ R / R Δ R / R ( m - 1 ) + m ≤ U 1 ′ ≤ V 2 Δ R / R Δ R / R 0 + m ( 13 )
[0079] It then follows from this that:
|U 1 ′|→0 for m→∞ (14)
[0080] As an example, with m=100 word lines, ΔR/R 0 =0.2 and U=2 V, the following are obtained:
[0081] U i ′=0 for like resistors in the i-th half-bridge, and
[0082] U i ′<0 for different resistors in the i-th half-bridge where 1.67 mV<|U 1 ′|<2.0 mV.
[0083] [0083]FIG. 12 shows the advantage, by comparison therewith, which can be attained with the use of the current follower 5 .
[0084] The following first holds true for the currents:
- I = I 1 - I 2 = V 2 R 11 - V 2 R 21 ( 15 )
[0085] With R 11 =R 0 , R 21 =R 0 +ΔR, the following is obtained:
- I = V 2 R 0 - V 2 ( R 0 + Δ R ) = V 2 Δ R R 0 ( R 0 + Δ R ) ( 16 )
[0086] With U ia ′=−R f ·I, it follows that:
U ia ′ = R f V 2 Δ R R 0 ( R 0 + Δ R ) = R f R 0 V 2 Δ R / R0 ( 1 + Δ R / R 0 ) ( 17 )
[0087] It can be seen from equation (17) that the output voltage U 1a ′ is independent of m and hence independent of the number of word lines.
[0088] A concrete example where ΔR/R 0 =0.2, U=2 V and R f =R 0 (R f is the resistance of the current follower 5 produces the following:
[0089] U 1a ′=0 for like resistors in the i-th half-bridge and
[0090] U 1a ′=0.2/1.2 V=0.166 V for different resistors in the i-th half-bridge, independently of m.
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A read/write architecture for a MRAM is described. The read/write architecture uses resistance bridges during the read process, whereby a memory cell in the resistance bridges having a known state of magnetization is compared with a memory cell that is to be measured.
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CROSS-REFERENCE TO RELATED APPLICATION
The present application claims the benefit of previously filed co-pending Provisional Patent Application, Ser. No. 60/513,675.
FIELD OF THE INVENTION
The field of the invention relates generally to a method of construction and more specifically to constructing factory prefabricated and finished forms for load bearing wall panels, ceiling/floor sections, roof sections and modules comprised of the same for use in a single family or single story building as well as for use in a multi-level and multi-unit building.
BACKGROUND OF THE INVENTION
Noncombustible, building construction typically is of one of five basic structural types or combinations thereof: 1) reinforced concrete frame; 2) reinforced wall bearing masonry; 3) structural steel framework; 4) precast concrete framework; or 5) light gage steel bearing wall. Each of these methods of construction is subject to cost disadvantages due to one or more of: time, labor, materials, weight, and complexity of assembly. Reinforced concrete frame construction requires the on site labor and time to build forms for the wet concrete, waiting for it to harden, and then time and labor to remove the used forms. Thereupon, the building is completed and finished on site with expensive job site labor and materials. Reinforced wall bearing masonry uses concrete block walls held together with mortar, then reinforced with steel rods and filled with concrete to produce the bearing walls. This approach is used extensively in residential construction but is limited to a few stories high. The biggest disadvantage has to do with adding plumbing, wiring and finishing material with job site labor, at prime cost. Structural steel or pre-cast concrete framework construction is commonly used in high-rise work, but require the heavy steel or concrete supporting frame structure; the ceilings, walls and all the interiors and exteriors to be completed and finished with on site labor and materials, a costly construction.
Light gage steel bearing wall construction employs framing partitions of light gage steel members assembled into panels. These members are load bearing and can be assembled into panels at the job site, prior to erection, but can be assembled more economically in a controlled factory environment. However, the remainder of the building then is completed and finished with costly job site labor and materials.
U.S. Pat. No. 4,409,764 by Wilnau discloses a system for constructing the structural framework of a building or other structure of reinforced concrete that is characterized by column and beam forms of sheet metal which remain in place as permanent parts of the framework after being filled with concrete. These forms are factory-assembled, together with the necessary internal metal reinforcing skeletons, and shipped to the building site ready for erection of the column forms and interconnection thereof by the beam forms. When the column and beam structure is complete, the curtain walls must be assembled and finished on site. This current invention describes a system of load bearing walls which function as curtain walls as well as the super structure.
U.S. Pat. No. 5,048,257 by Luedtke discloses a method of constructing multiple story buildings, particularly detention structures, whereby the framing members are lightweight steel channel members that are generally similar and in certain applications, interchangeable. The walls and floors of the building are framed with the channel members and lathe sheathing is applied, with cementitious fill there between. This specification does explain a stay in place forming system. It describes the placement of the fill as being observed through the lath to assure a solid fill. Luedtke later explains the subsequent application of cement plaster or stucco like material. This terminology necessarily infers that the plaster or stucco like material is applied after the concrete has cured, possibly to assure a straight wall that bowed during the placement of plastic concrete. The Luedtke design discusses a method of concrete delivery consisting of a fill hose as pictured in FIG. 6 of the patent. This practice is not practical and probably not possible, at least not at the low slump mentioned and required to achieve the strength provided by the proper water to cement ratio.
While both Wilnau and Luedtke combine the advantages of reinforced concrete and steel framework by using portions of the steel framework as non-removable forms for the poured concrete columns and beams, these inventions do not take full advantage of the efficiencies and cost savings that can be obtained by factory prefabrication of not only the structural wall panel, but also of the window casings and door jambs contained in the wall panels that also serve as an integral form for receiving the poured concrete. Further, these inventions do not take advantage of the cost-savings that can be achieved by factory pre-finishing the wall panels with plaster or stucco like material and paint or wallpaper.
Another invention, U.S. Pat. No. 3,983,368 by Perrin discloses an invention whereby a wall is formed as by spraying cementitious material through and around two panels of sheet material thus to produce a composite wall with a hollow core therebetween, such core to be filled with a rigid material. This design is a sandwich panel where the core is described as a cellulostic material referred to as corrugated paperboard or cardboard. The voids within the core appear to be very small at least as compared to the current invention which is a forming system for achieving conventional steel reinforced concrete in a more economical fashion. Although Perrin's wall panel contemplates a sprayed plaster or stucco like material finish, just as in Wilnau and Luedtke, it also does not take advantage of prefabricating window and door jambs as an integral part of the framing structure. Further, Perrin's invention relies on the use of a reinforced rigid core for its load-bearing properties. While suitable for residential housing, such construction will not provide the load-bearing capacity that the use of conventional steel reinforced concrete provides as disclosed in the present invention.
The Anderson U.S. Pat. No. 5,996,293 describes a window buck devoted to providing an opening. The current invention does define an opening but the hollow metal jamb also functions as an integral part of the structural framework, provides a stop for the mounting of doors and windows and is ideally suited as a termination device for the finished surfaced surfaces.
SUMMARY OF THE INVENTION
The present invention discloses a method that overcomes the disadvantages of prior art by taking full advantage of the efficiencies and cost savings that can be obtained by factory prefabrication of a much larger unit of construction with far more value added under industrialized conditions where both cost and quality can be controlled. All effort is to be expended at the time and place where the benefit can be maximized while the cost is minimized. Everything that is ever to go inside a wall, ceiling or roof section is to be added as the section is being assembled on the framing table, except the steel reinforcement (rebar) and concrete. Every surface of every section that should ever be finished will be finished on the framing table in the horizontal position with the side to be finished facing up. Notable exceptions are the surfaces that must be left open to place the steel and concrete. In the case of wall sections, the top surface will never be exposed. The top surface of the floor section will be exposed but it is much less costly to field apply the concrete from the top and finish the floor than apply the concrete from the bottom and finish the ceiling. The roof section is a different matter; it is much less expensive to apply the concrete from the bottom and finish the ceiling than to finish the roof surface. Finished surfaces include paint, wall paper, veneer of every type and roof covering.
The integrally formed wall panels are constructed of modified steel studs, rigid insulating material, and metal rib-lathe imbedded in plaster or stucco like material or stucco type material. The three elements of the side wall function as a composite material of structural integrity sufficient to withstand the forces of the plastic concrete added at the job site. The primary function of the steel stud is to hold the two composite sides in place during hauling, erection and the placement of concrete. A second objective is to hold the rigid insulation in place until the plaster or stucco like material or stucco type material has been applied. The primary function of the insulation is to act as a thermal resistance, but it also acts as a back stop for the plaster or stucco like material or stucco type application and as an integral part of the composite side wall. The rib-lathe is steel reinforcement for the plaster or stucco like material or stucco type but the rib is also the member that holds the studs in place during the fabrication of the wall section. Notice that top and bottom plates, as is normally used in conventional construction to hold the studs in place, must be avoided in this design in order to keep the void open for easy access at the top, and for interconnection at the bottom.
The integrally formed monolithic ceiling/floor panels are constructed of U-shaped “gull wing” steel joists, rigid insulation, “C” channels, metal lathes, and plaster or stucco like material. As in the wall section, the insulation, lathe and plaster or stucco like material are combined to create a composite material, sufficient to withstand the forces of hauling, erection and the application of the finished floor. The joists are placed in position first and must be of sufficient size and strength to span the required distance and support the application of reinforcement steel, and the concrete, which is, field applied later. The insulation is installed second and then the “C” channels are placed at the ends of the joists. These are necessary to hold the system together for assembly, hauling and erection. This section is fabricated on the framing table in the upside down position, which is with the ceiling facing up. Next the lathe is added and the plaster or stucco like material is applied and finished.
In general sections are made up of parts. Sections are assembled to create modules. A module is made up of four wall sections and one ceiling/floor section. The ceiling of one module will function as the floor of the module above. Each is a five-sided cube. The module, which is hauled and erected at the job site, does not have either a bottom or a floor. This configuration of a 5 sided cube allows the wheels of the carrier to come up inside the module thus lowering the center of gravity and allowing a higher ceiling while still allowing clearance under highway overpasses. The ceiling/floor section, serving as the top, provides a work platform for tradesmen in lieu of scaffolding.
Finally, the roof section is made up of a sheet metal covering, joists that function as rafters, and rigid insulation. The sheet metal is stamped or roll formed and pre-finished to achieve the correct appearance and functions as an integral part of the structural system. The joists are placed into position with the opening facing down and the insulation is then added. A ridge beam and cornice are added. The roof covering is then installed. The mechanical fasteners holding the roof covering membrane should always be at the high point of the membrane rather than in the trough where water would flow. The final roof assembly is field installed so that the rebar can be added and interconnected with adjacent sections before the zero slump concrete is shot into place. The rib-lathe and plaster or stucco like material are then applied and finished.
The primary objective of this specification is to describe Integral Forming Technology in terms of sections and modules where wall, ceiling and roof surfaces are machine finished and internally complete except for the steel reinforcement and concrete. These forms receive the concrete without distortion and remain as useful, functional and integral parts of the final product. It is important to note that every wall, including the smallest closet wall, is constructed the same way; every wall is structural and load bearing and functions as an integral part of the entire structure. Storm like forces are transmitted from any element to every adjoining element to the extent that every force is distributed equally throughout the monolithic whole.
It is therefore an object of the present invention to provide a method for constructing a unit of construction that, compared to traditional concrete and steel construction methods, has far more “value added” under industrialized conditions where cost and quality can be controlled.
It is therefore a further object of the invention to provide for a method of construction for factory prefabrication of load bearing wall panels and monolithic ceiling/floor sections for use in multi-story buildings.
It is a further object of the invention to provide a method of construction for constructing a wall panel consisting of studs and window casings and door jambs that creates an integral form for the concrete core thereby eliminating the need for any additional concrete form work on the job site.
It is a further object of the invention that the lighter-weight elements of standard construction methods that are labor and skill intensive are to be assembled and pre-finished in the factory taking advantage of automated machinery. After the integral forms have been transported to the site and erected, the heavy elements, re-bars and concrete, are placed in the forms.
It is a further object of the present invention to realize cost savings, efficiencies, and improved quality control by factory finishing both sides of the wall panels, the ceiling of the ceiling/floor section, and the top roof surface.
It is also an object of the present invention to create a construction system where the pre-finished forms are made up of individual materials combined to function as composites, which act in unity and therefore create a homogenous whole. The formed sections and modules provide ample access to field install steel reinforcement and place concrete to achieve a monolithic superstructure where every section mutually supports every adjoining section.
It is an object of the present invention to create a monolithic, ceiling/floor section structural unit that is more cost-efficient and has better structural integrity than individually constructed floor and ceiling elements.
It is an object of the present invention to create pre-finished sections useful for building anything that should be steel reinforced concrete, including but not limited to fences and walls of every type.
The accompanying drawings, which are incorporated in and constitute a part of this specification, together with the description, serve to explain the principles of the invention. The description of the preferred embodiment of this invention is given for purposes of explaining the principles thereof, and is not to be considered as limiting or restricting the invention since many modifications may be made by the exercise of skill in the art without departing from the scope of the invention.
BRIEF DESCRIPTION OF DRAWINGS
The following figures set forth the preferred embodiment of the present invention:
FIG. 1 depicts an overview of the concept;
FIGS. 2 a , 2 b , 2 c , and 2 d depicts views of a metal stud, modified to facilitate the manufacture of integral forms as described by this specification;
FIGS. 3 a and 3 b depicts a gull-wing metal joist to function as a floor joist or roof rafter and facilitate the manufacture of integral forms as described in the specification and a single wing metal joist respectively;
FIG. 4 depicts a rib lathe, a standard product currently in production and readily available;
FIG. 5 depicts a hollow metal door and window jamb frame;
FIG. 6 shows a plaster or stucco like material stop;
FIG. 7 depicts a “C” channel to hold the gull-wing joist in place;
FIG. 8 depicts an assembly of wall section;
FIG. 9 shows a ceiling/floor section assembly;
FIG. 10 depicts addition of “C” channel to ceiling/floor section assembly;
FIG. 11 shows a cross section of the assembly of a ceiling/floor section;
FIG. 12 depicts the attachment of walls to each other;
FIG. 13 depicts the ceiling/floor section attachment to exterior walls below;
FIG. 14 shows a stack and arrangement of modules and sections on site;
FIG. 15 depicts a party wall juncture;
FIG. 16 shows a plan view of party wall;
FIG. 17 shows a roof section assembly; and
FIG. 18 depicts a roof section installation.
DETAILED DESCRIPTION OF THE INVENTION
Integral Forming Technology (IFT) describes a method of factory finishing wall, ceiling and roof sections where all of the internal elements are included. The sections can be assembled into modules in the plant or erected on the site. The sections and or modules appear to be finished except the steel reinforcement (rebar) and concrete has not been placed. Integral forms are best described as a much larger unit of construction, with far more value added under industrialized conditions, where both cost and quality can be controlled. The integral forms can be stacked and arranged with the flexibility to achieve virtually any architectural effect. Integral forming is a method of constructing steel reinforced concrete buildings of any size and for any purpose. The disclosed system has been designed to enclose more space that is more desirable, more attractive and more comfortable, is more structurally significant; and, is less expensive to build, operate and maintain than any currently available. To better explain the preferred embodiment of the invention the following numbering system is used:
1 . Modified Stud 2 . Rigid Insulation 3 . Rib lathe 4 . Concrete 5 . The Void 6 . Steel reinforcement 7 . Gull wing joist 7 . a Single wing joist 8 . Opening jamb frame 9 . Plaster or Stucco like material stop 10 . “C” channel 11 . Wall section assembly 12 . Ceiling/floor section assembly 13 . Module 14 . Pre-finished sheet steel roof membrane 15 . Steel reinforcement holes 16 . Wiring/plumbing holes 17 . Attachment clips 18 . Mechanical fastener 19 . Plaster or Stucco like material 20 . Tabs 21 . Cornice
Referring now to the drawings FIG. 1 discloses an overview of the concept showing how the pre finished sides of the integral form will be held in place relative to each other by the modified studs ( 1 ) creating the voids ( 5 ) which are readily accessible to receive the field placement of the steel reinforcement ( 6 ) and concrete ( 4 ).
FIGS. 2 a , 2 b , and 2 c discloses views of modified studs ( 1 ); Unmodified studs are currently produced in large quantity and in a number of sizes and gauges of sheet metal that are well known in the art. The standard studs are easily modified with tabs and voids as shown in the figures. The modified studs ( 1 ) are in a wall section assembly ( 11 ), as shown in FIG. 8 , in the vertical position and are to resist loads, both compressive and tensile. As far as an Integral Form is concerned, the primary function of the modified studs ( 1 ) is to hold the two composite sides in place until the concrete ( 4 ) has cured. Modified as shown, the tabs ( 20 ) in the modified studs ( 1 ) are to hold the rigid insulation ( 2 ) in place until the rib lathe ( 3 ) has been added and the plaster or stucco like material ( 19 ) has been applied. The plaster or stucco like material ( 19 ) is sprayed on under pressure and bonds with both the rib lathe ( 3 ) and the rigid insulation ( 2 ). The three, properly bonded together, function as a composite side. The steel reinforcement holes ( 15 ) in the center of the modified studs ( 1 ) are to allow the passage of steel reinforcement ( 6 ) and hold it near the center of the concrete ( 4 ) to be added later. The much larger oblong holes on the centerline of the modified studs ( 1 ) are to allow free passage of the concrete ( 4 ) in the horizontal direction. The wiring/plumbing holes ( 16 ) to the side are to allow passage of pipe, conduit and wiring of every type through the modified studs ( 1 ) and rigid insulation ( 2 ) which will be notched as required.
FIGS. 3 a and 3 b discloses the gull wing joist ( 7 ). The primary function of a joist is to span a distance between two supporting elements. This gull wing joist ( 7 ) is designed to create a void for steel ( 6 ) and concrete ( 4 ) that will be poured on site. The gull wings on the gull wing joist ( 7 ) are to hold the rigid insulation ( 2 ) in place. Note that the wing must be removed from one side of the end gull wing joist ( 7 ), effectively resulting in a single wing joist ( 7 . a ). Notice also that the gull wing joist ( 7 ) used in the upside down position functions as a roof rafter.
FIG. 4 discloses the rib lathe ( 3 ). The rib lathe ( 3 ) is steel and effectively acts as reinforcement for the plaster or stucco like material ( 19 ). The ribs of the rib lathe ( 3 ) itself is solid, meaning not perforated, and is a more structural element serving to provide rigidity in the horizontal position which is perpendicular to the modified studs ( 1 ) and intended to hold the modified studs ( 1 ) in the proper position.
FIG. 5 is an isometric view of an opening jamb frame ( 8 ). This standard opening jamb frame ( 8 ) is used to frame door and window openings, and facilitate the mounting of same. This opening jamb frame ( 8 ) must be installed during the framing stage to define the opening and provide a stop for applying the plaster or stucco like material ( 19 ). All window and door opening jamb frames ( 8 ) are installed while the wall section is still lying flat on a framing table (not shown).
FIG. 6 discloses a plaster or stucco like material stop ( 9 ) that is used to provide a connection device for the wall section assembly ( 11 ) to the floor/ceiling section assembly ( 12 ), and provide a reference for placement of the plaster or stucco like material ( 19 ).
FIG. 7 discloses a C channel ( 10 ) used to hold the floor/ceiling section assembly ( 12 ), which is more fully disclosed in figure ( 9 ), together while assembly and installation of the finished module ( 13 ) and/or while hauling and erection of the module ( 13 ) at the job site. The modules ( 13 ) are more fully disclosed in FIG. 14 .
FIG. 8 shows how the parts will be assembled to make a wall section assembly ( 11 ). The first modified stud ( 1 ) is put in place on a framing table. The bottom rigid insulation ( 2 ) is then put in place, and the top rigid insulation ( 2 ) and the second modified stud ( 1 ) is added simultaneously. This sequence is repeated starting with the bottom rigid insulation ( 2 ). All piping, wiring, conduit and opening jamb frames ( 8 ) must be added at this time. Rib lathe ( 3 ) is added next and then the plaster or stucco like material stop ( 9 ). With everything in place the plaster or stucco like material ( 19 ) is then added to one side of the wall section assembly ( 11 ). The wall section assembly ( 11 ) is then turned over and the plaster or stucco like material ( 19 ) is added to the other side of the wall section assembly ( 11 ).
FIG. 9 discloses the floor/ceiling section assembly ( 12 ) manufacture wherein the first gull wing joist ( 7 ) will be laid in place and then the first rigid insulation ( 2 ). This sequence will be repeated as required.
FIG. 10 discloses how the C channel ( 10 ) is added to hold the floor/ceiling section assembly ( 12 ) together during fabrication and erection.
FIG. 11 further discloses part of the assembly of the floor/ceiling section assembly ( 12 ). With the floor/ceiling section assembly ( 12 ) in the upside-down position, the rib lathe ( 3 ) is added and then the plaster or stucco like material ( 19 ) is applied and finished.
FIG. 12 discloses how angled attachment clips ( 17 ) are attached to the abutting wall section assembly ( 11 ), and then the two wall section assemblies ( 11 ) are to be placed in the proper position and the attachment clips ( 17 ) are attached to the abutment wall section assembly ( 11 ).
FIG. 13 shows how the floor/ceiling section assembly ( 12 ) is attached to an exterior wall section assembly ( 11 ). This condition is the same for module ( 13 ) assembly in the plant or field erection of walls and floors on site. Notice that the outermost wall of the exterior wall section assembly ( 11 ) is higher than the innermost wall, this extension is to act as a rim beam as used in conventional construction. Also, the plaster or stucco like material ( 19 ) may not be applied all the way to the edges of the wall section assemblies ( 11 ) and floor/ceiling section assemblies ( 12 ) which allows for the addition of a corner piece of wire lathe (not shown) to be added as a part of the module assembly in the factory or while assembling in the field for additional structural integrity. The plaster or stucco like material ( 19 ) would then be added to the areas where it was left off after assembly.
FIG. 14 shows a possible sequence for stacking and arranging modules ( 13 ), wall section assemblies ( 11 ), and floor/ceiling section assemblies ( 12 ) on the job site. Note that the greatest stacking and arranging advantage is achieved when an odd number of modules ( 13 ) are used. The odd numbered modules ( 13 ) are full modules ( 13 ), while the additional sections ( 11 and 12 ) create enclosed spaces between the modules ( 13 ).
FIG. 15 shows floor/ceiling connection to the party wall section assembly ( 11 ) section below. The party wall section assembly ( 11 ) and the right floor/ceiling section assembly ( 12 ) are delivered to the site as part of a module ( 13 ) while the left floor/ceiling section is installed at the site as a section.
FIG. 16 is a plan view of FIG. 15 . Note the accessibility of the voids ( 5 ) within the wall section assembly ( 11 ) and interconnectivity with the voids ( 5 ) within the interior of the gull wing joist ( 7 ).
FIG. 17 shows how the gull wing joists ( 7 ) are to be installed on a framing table in the upside-down position such that they will function as roof rafters. The rigid insulation ( 2 ) is added next and then the pre-finished sheet steel roof membrane ( 14 ) as a water proofing membrane. The assembly is designed for a mechanical fastener ( 18 ) to penetrate the pre-finished sheet steel roof membrane ( 14 ) at the high point.
FIG. 18 shows the roof section, complete with the cornice ( 21 ), being installed atop a wall section assembly ( 11 ) on the site. With the roof section in its final position, the interconnecting steel reinforcement ( 6 ) will be added and zero slump concrete ( 4 ) will be shot into place within the interior voids ( 5 ) of the gull wing joist ( 7 ). Next the rib lathe ( 3 ) will be added and the plaster or stucco like material ( 19 ) will be installed on the ceiling and finished as appropriate.
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A method for constructing factory prefabricated and finished load bearing wall panels and monolithic ceiling/floor sections and modules comprised of the same for use in a single family or single story building as well as a multi-level and multi-unit building. The integrally formed wall panels are constructed of modified steel studs, rigid insulating material, and metal lathe and are factory finished with plaster or stucco like material. A void is defined by the modified steel studs window casings and door jambs. Upon erection and assembly at the job site, steel rebar is placed in such voids that are then filled with concrete, thereby eliminating the need for any additional concrete form work.
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This application claims the benefit of U.S. provisional patent application No. 60/385,391 filed on Jun. 3, 2002.
FIELD OF THE INVENTION
The present invention relates to an apparatus having improved recording quality in inkjet printing systems having a shuttling print head and more specifically an ink tank for such an apparatus having a stable pressure in the supply chamber to such a print head.
BACKGROUND OF THE INVENTION
Inkjet Printing
Nowadays a lot of printed matter is produced carrying a reproduction of a colour image. A large part of these colour prints are produced using offset printing but in office and home environment a lot of colour prints are made using relatively small printing apparatuses. One of the possible printers used is an inkjet printer. In an inkjet printer drops of ink are jetted out of a nozzle toward a receiving layer which may be e.g. specially coated paper.
Usually an inkjet print head has an array of nozzles, each nozzle jetting ink to different locations at the same time.
The ink is jetted out of the nozzles by use of e.g. thermal or piezoelectric actuators creating a pressure wave.
It is normally the intention that the size of the droplets can be kept constant or that there is a good control of the droplet size in printers capable of recording variable droplet sizes.
Print Head
In FIG. 1 an inkjet print head is depicted with capillary tubes 1 having a nozzle end and a inlet end. For each tube 1 an actuator 2 is provided for causing a pressure wave expelling the ink out of the nozzle at the end. At the other end ink is fed to the print head from an ink tank.
In normal rest condition the ink forming a meniscus 3 at the nozzle end in the capillary tubes 1 is influenced by surface tension forces. Another force acting upon the ink is the “hydrostatic” pressure caused by gravity due to the height of the ink above the meniscus 3 . Because the inkjet print head is fully filled with ink and it is connected to the ink tank, the level of the ink in the ink tank determines the pressure of the ink in the print head. When placing the ink tank above the print head, a positive ink pressure will arise due to the vertical height difference between ink level and nozzles.
Some types of print heads need a stable negative ink pressure at the nozzle area for good printing.
To reach finally a negative pressure at the nozzles, this positive pressure can be neutralised by applying a negative pressure above the ink in the header tank.
A problem is that in order to obtain constant or controllable recording quality the negative pressure in the head and tank is to be kept constant or within a small range.
Shuttling Print Head with Header Tank
In recent time inkjet printing technology is also used in large format, high volume printers
Inkjet print heads can be as large as the transversal size of an image or text to be printed but usually the size of the print head is smaller. Page wide print heads are still expensive and less reliable than smaller types.
FIG. 2 gives a view of how an inkjet printer composes a whole image. A receiving sheet 4 , e.g. a sheet of paper is transported in one direction (transport direction indicated by arrow A) and passed gradually underneath the printing station.
The print head 5 which has a size smaller than the receiving sheet 4 shuttles transversal (indicated by arrow B) over it and consecutively records one or more lines when shutting over the sheet 4 paper. The image is composed gradually.
It is possible that several print heads are used to record different colours and a colour image is recorded by superposition of the different colour images.
In order to enable continuous operation of a print head 5 , an ink tank containing an ink supply is coupled to the print head 5 . Small printers usually have a small cartridge, optionally with integrated print head nozzles, containing only a limited amount of ink.
When empty these cartridges have to be replaced. High end inkjet printers having a high throughput or large formats however consume a large amount of ink.
The inkjet print head of a high end printer is coupled with an ink tank and mounted on the shuttling carriage carrying the print head. This ink tank is called a header tank and can be refilled out of a large capacity ink tank which is stationary.
Refilling of the Header Tank
Possible refill arrangements can be found in EP-A1 097 814, herein incorporated by reference in its entirety as background information. When the level of ink in the header tank is too low the shuttling carriage is transported to a refilling station outside the printing area where the header tank is refilled.
A considerable problem in this method is the difficulty to maintain a constant ink pressure in the print head. The height of the level of ink in the header tank diminishes constantly giving rise to less pressure due to gravity and causing variations in recording quality.
The level can be kept relatively constant by refilling very often but no recording can be done during refilling giving rise to lower throughput rates as the carriage has to be stopped each time.
In EP-A-1 142 713, herein incorporated by reference in its entirety as background information, a system for refilling a header tank is described wherein refilling can be done during printing. The header tank on the shuttling carriage is connected by flexible tubes to a feeder tank. The main tank is pressurised and when a replenishing valve is opened ink is pressed by the air pressure from the feeder tank to the header tank during printing operation. A supplementary valve is placed between the header tank and the print head.
It is an overall problem to keep the pressure in the print head at a constant level:
the “hydrostatic” pressure has to be counteracted during printing, even during refilling the header tank with large amounts of ink. the “hydrostatic” pressure may vary due to acceleration forces during shuttling. It is clear that during acceleration the ink surface will not be horizontal and that accelerations produce pressure gradients within the header tank. A reliable method for measuring the ink level in the header tank is necessary to ensure accurate refilling of the header tank. Due to the movement of the ink within the header tank the measurement of a float may not be reliable.
It is desirable that a system is provided capable of exactly metering the amount of ink that is fed to the header tank.
Another problem is that during shuttling of the carriage carrying the header tank, the ink is whipped up and bubbles of trapped air are likely formed within the ink. As these bubbles can be transported to the print head with the flow of ink, they may give rise to defects in the printed image. No extra measures have been taken in the prior art in order to avoid or counteract the effect of the air bubbles.
When shuttling the ink tank simultaneously with the print head, mechanisms should be implemented for damping the pressure fluctuations in the ink connection to the print head, due to the movement of the carriage. Pressure variations can have negative influence on print quality.
A further problem is that to allow a compact staggering of print heads, the ink tank dimensions should be smaller than the print head itself.
SUMMARY OF THE INVENTION
The above-mentioned drawbacks are counteracted by an apparatus having the specific features set out in claim 1 . Specific features for preferred embodiments of the invention are set out in the dependent claims.
Further advantages and embodiments of the present invention will become apparent from the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a cross-section of an inkjet print head.
FIG. 2 illustrates the overall printing principle of an inkjet printer with a shuttling print head.
FIG. 3A shows a cross section of an ink tank according to the invention.
FIG. 3B gives an isometric view of a dual ink tank assembly
FIGS. 4A to 4 C show the ink level in a tank during acceleration and during rest or continuous motion.
FIG. 5 shows an horizontal cross-section of a dual ink tank assembly.
DETAILED DESCRIPTION OF THE INVENTION
The present invention solves above mentioned drawbacks by providing a header tank having functional elements arranged symmetrical to the centre plane perpendicular to the direction of movement of the shuttling carriage of the printer.
Next a preferred embodiment of an ink tank according to the present invention is described.
FIG. 3A depicts a cross section perpendicular to the shuttling direction of a header tank 6 according to the present invention.
FIG. 3B shows a combination of 2 tanks having further features which will be described later on.
FIG. 5 gives a horizontal section of the dual tank combination.
The double pointed arrow B indicates the shuttling direction of the print carriage containing the print head and the header tank. Plane P is the centre plane perpendicular to this direction.
The ink tank 6 has an ink chamber 7 and contains or is in connection with several functional elements.
As functional elements are considered all features which have an influence upon the working of the ink tank 6 .
Several functional features can be seen in this view.
Ink is fed via ink feed outlet 8 from the bottom of the ink chamber 7 to the inkjet print head 5 . The height difference between the ink level and print head is defining the gravimetric pressure in the print head and height differences should be minimised. Placement of outlet 8 should be kept constant to avoid pressure fluctuations. The pressure in the print head 5 is directly determined by the pressure at the feed outlet 8 of the header tank 6 . The supply inlet 10 of the header tank 6 enables replenishment of the ink in the ink chamber 7 using ink from the main tank to the header tank during replenishment. The inlet is formed by a tube reaching below the ink level in the header tank 6 in order to allow smooth refilling. Care has to be taken that during replenishment no pressure variations are generated due to the inflow of fresh ink. At the vacuum inlet 9 on top of the ink chamber 7 a stable negative pressure is applied to the ink chamber 7 of the header tank 6 to compensate the positive “hydrostatic” pressure due to gravity. This is realised by air extraction on the top of the ink chamber 7 , above the ink level. A system for providing the vacuum or negative pressure to the ink chamber 7 will be described later. re-flow inlet 11 is connected to the print head 5 in order to allow re-flow of air bubbles originating from the print head 5 to the ink chamber 7 . A small channel 12 provides connection with the ink chamber above the ink level.
FIGS. 4A to 4 C depict the ink level in an ink tank 6 during three stages.
acceleration to the left, acceleration to the right, without acceleration (e.g. shuttling stopped)
It the three cases the ink amount in the header tank 6 is identical.
As is illustrated the ink surface in the ink chamber during state L in FIG. 4A and R in FIG. 4C is inclined due to the acceleration of the ink tank and the inertia of the ink in the ink chamber. A gradient of the hydrostatic pressure is created within the body of the ink. Because the feed outlet 8 is situated in the centre plane perpendicular to the direction of movement of the carriage, the height of the ink level h at the position of the outlet 8 in the ink chamber 7 is not influenced as can be seen in FIG. 4A to FIG. 4 C. The inclination of the ink level (due to ac- and deceleration of the carriage) is pivoting symmetrically and the level height h in the middle of each tank stays stable. By placing the ink outlet 8 to the print head along the centre plane pressure variations due to shuttling of the head can be minimised.
When considering the location of the inlet 10 for ink replenishment into the chamber 7 it is to be avoided that inflow of the ink causes pressure changes. The most neutral placement of the inlet 10 is also in the centre plane of the ink chamber 7 . The inlet 10 constructed to ensure that ink is supplied under the ink level in order to avoid drops falling into the tank causing e.g. trapping of air in bubbles etc.
A further functional feature is the system regulating the ink level in the ink chamber. 7
A constant ink level is realised by an ink level sensor. Inside the ink chamber 7 a float 13 is provided having a integrated magnet 14 In combination with a reed contact 15 which is fixed at the outside of the ink chamber 7 a level detection system is provided.
The ink tank 6 is suited for inks with different specific gravity, by choosing a big volume of the float 13 it is dimensioned for low specific density (i.e. oil based) inks.
By choosing the dimensions of the float 13 big in relation to the dimensions of the ink tank 6 , a certain dampening of ink movement is obtained.
The float 13 can be mounted in the ink chamber 7 using a hinge having low tolerance in order to ensure that the position remains central inside the ink chamber 7 during shuttling movement.
Preferable the float 13 itself is also symmetrical.
The ink level h can be kept constant, independent of the ink type, by adjusting the fixing height of the reed contact 15 .
By constructing the float 13 symmetrical regarding to the centre plane perpendicular to the shuttling direction B the reading of the ink level sensor system it is not influenced by the position of the ink level surfaces as shown in FIGS. 4A AND 4C .
The reed contact 15 commands a pump for pumping ink from the main tank to the header tank 6 during replenishment of the header tank 6 .
Further an ink movement damper 16 for dampening further pressure variations, due to the shuttling, is integrated in the ink tank 6 .
This ink movement damper 16 is located between the ink chamber 7 and the ink outlet 8 to the print head 5 . To restrict ink movement inside the damper 16 , the dimensions are chosen smaller than the width of the ink chamber 7 . Preferably the size in the shuttling direction B is less than half the size of the ink chamber 7 .
The damper 16 can be executed in the form of a labyrinth, a mesh or a porous member restricting movement of the ink near the outlet opening 8 of the ink chamber 7 . In FIG. 3 a labyrinth is shown in the right side of the ink chamber 7 . Several partitions 17 having perforations at different heights are provided so the ink can not travel in a straight path to the outlet opening 8 . In order to avoid pressure and flow variations due to the shuttling movement the damper 16 is constructed symmetrically regarding the centre plane of the ink tank 6 .
This damper 16 has also a important degassing function of ink flowing from ink chamber 7 into the print head.
As ink is fed from the ink chamber 7 to the outlet 8 . A flow of ink is induced through the damper 16 . The ink is forced to take several turns through the labyrinth formed by partitions 17 . Air bubbles trapped in the ink have the tendency to rise to the top, where they can join with the air above the ink level in the tank 6 . The air outlet of the ink damper 16 preferably has to reach above the ink level.
Because of the application of a constant negative pressure an amount of trapped air tends to form a greater bubble than at atmospheric pressure and therefore can be more easily separated because large bubbles tend to rise more quickly.
The ink feed system for the print head 5 is realised by two ink connections between ink tank 6 and print head 5 .
A first connection from the ink outlet 8 to the print head 5 is on the bottom of the ink tank 6 , behind the damper 16 . This opening is feeding ink into the print head 5 .
A second connection coupled to the re-flow inlet 11 will allow air-bubbles to return from the print head 5 into the ink tank 6 . This is especially important if a new (empty) print head 5 is to be filled with ink. The height of the connection of the opening with the tank 6 is located above the ink level in the ink tank 6 .
Via this connection the negative pressure is also supplied to the inkjet print head 5 directly.
In order to provide a constant vacuum source the ink tank 6 is connected to a large volume vacuum container in which vacuum is sustained by a small capacity extraction pump under control of a precise pressure regulator. By choosing a large vacuum reserve, pressure will not vary easily even during a replenishment step in which a large amount of ink is added to the header tank 6 . The pressure of a large vacuum holder will vary only with a small amount when a relatively small volume of ink is added to the system. The volume of the vacuum reservoir preferably is at least 5 times larger than the volume of the ink chamber 7 . More preferably the volume of the vacuum reservoir is 50 to 100 times larger than the volume of the ink chamber 7 .
The ink tank 6 can for the greater part be produced using known processes like injection moulding. To the inner sides of the ink chamber 7 a special coating can be applied in order to obtain oleophobic characteristics.
In order to lower production costs it is possible to produce assemblies of coupled ink tanks 6 having common side-walls. A combination of two ink tanks is shown in FIG. 5 .
As for each colour a separate tank is to be provided the use of combinations of ink tanks 6 having a common side-wall 18 has a cost advantage.
Another possibility is that in the common side-walls 18 of the tanks 6 special break-away seals 19 is provided which can be removed so that out of the multiple tanks 6 a single tank can be made. E.g. for use in a high-end black and white printer. The connection of the ink tanks 6 can also be made in other ways, e.g. special ink channel 20 can be provided with breakable seals 19 .
In order to prevent ink level variations during shuttling, the dimensions of the unsealed opening have to be small so only a small amount of ink can pass through the opening between the tanks 6 during shuttling.
The combination of several tanks 6 has a further advantage. As can be seen in FIGS. 3A , 3 B and 5 , the ink tanks 6 are equipped with several mounting holes/slits 21 in order to allow easy replacement of the ink tank 6 using screws or other fastening means in the printer. Preferably mounting means having quick release systems are used. This can be necessary when changing ink type or colour in the inkjet printing apparatus. When several tanks 6 are mounted together on the shuttling carriage, replacement can be done quicker than when each tank 6 is mounted separately.
Having described in detail preferred embodiments of the current invention, it will now be apparent to those skilled in the art that numerous modifications can be made therein without departing from the scope of the invention as defined in the appending claims.
PART LIST
1 . capillary tubes
2 . actuators
3 . meniscus
4 . receiving sheet
5 . print head
6 . header tank
7 . ink chamber
8 . ink feed outlet
9 . vacuum inlet
10 . supply inlet
11 . re-flow inlet
12 . channel
13 . float
14 . magnet
15 . reed contact
16 . damper
17 . partitions
18 . common sidewall
19 . break-away seal
20 . ink channel
21 . mounting hole/slit
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An ink tank and a print head are mounted on a carriage for supplying ink to an inkjet print. The ink tank includes: one or more ink chambers, where each of the ink chambers includes one or more functional elements (1) symmetrically arranged, mounted and centered about a center plane of the respective ink chamber, and (2) positioned perpendicular to a direction of movement of the carriage. The functional elements include, for example, a feed outlet for feeding ink to the print head, a supply inlet for supplying ink to the ink chamber, an ink movement damper, an ink level sensor, a vacuum inlet to extract air from the ink chamber, and a re-flow inlet to allow re-flow of air bubbles from the print head to the ink chamber.
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[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/798,137, filed May 4, 2006, which is herein incorporated by reference in its entirety.
[0002] This invention was made partly using funds from the National Institutes of Health contract number 1RO1 CA104569-01 and -03. The U.S. Federal Government may have certain rights to this invention.
TECHNICAL FIELD
[0003] The present invention provides novel compounds having filamentous actin binding activity. The invention further provides methods for synthesizing the compounds.
BACKGROUND ART
[0004] Phalloidin is an actin-binding toxin whose chemistry and bioactivity have been studied since the early 1900s (see, for example, Wieland, T., (1986) Peptides of Poisonous Amanita Mushrooms. ed.; Springer-Verlag: New York, page 256). Phalloidin binds with high affinity to filamentous actin (F-actin) and lowers the critical concentration of actin polymerization in solution. It has been used extensively to study actin dynamics in vitro, and fluorescent analogs of phalloidin provide highly specific reagents for microscopic visualization of the actin cytoskeleton (see, for example, Pringle, J. R., et al. (1991) Methods Enzymol. 194: 729-731. The natural source of phalloidin, Amanita phalloides, the Death Cap mushroom, lives in a complex ecological relationship with host trees and is widely considered to be uncultivable (Wieland (1986) supra). Pure phalloidin sells for ˜$150 per milligram and its fluorescent conjugates are much more expensive. In our efforts to develop high-throughput cell-based screens for compounds that modulate actin cytoskeletal morphology, we have sought an inexpensive source of fluorescently labeled phalloidin. Although there have been a number of syntheses of phalloidin analogs both in solution and on the solid phase, no synthetic route has been published with yields significant enough to provide this reagent in practical quantities. These syntheses reported yields ranging from 0.5% to 1.3% and relied on the preparation of relatively complex building blocks in solution. (See Wulf, E. et al. (1979) Proc. Natl. Acad. Sci., 76: 4498-4502; Falcigno, L. et al. (2001) Chemistry—A European Journal, 7: 4665-4673; Zanotti, G. et al. (2001) Chem. Eur. J. 7: 1479-1485; and Anderson, M. O. and Guy, R. K., (2005) J. Org. Chem. 70: 4578-4584.)
[0005] Phalloidin is a bicyclic heptapeptide that contains an unusual bridging thioether linkage between the Cys and Trp residues. The natural product contains four common L -amino acids, a D -threonine residue, an unusual γ,δ-dihydroxy-L-leucine residue, and the rare cis epimer of 3-hydroxy-L-proline. Structure-activity studies have shown that the γ,δ-dihydroxy- L -leucine side chain is not essential for actin binding (see Anderson, M. O. and Guy, R. K., (2005) supra; and Wieland, T., (1983) Int. J. Pept. Protein Res., 22: 257-276).
[0006] In efforts to develop high-throughput cell-based screens for compounds that modulate actin cytoskeletal morphology, an inexpensive source of fluorescently labeled phalloidin has been sought.
[0007] It is desirable to provide improved approaches, including both compounds and methods for their synthesis, for use in the study of the cytoskeleton and cellular morphology and for developing compounds for treating patients suffering from liver failure due to consumption or ingestion of phalloidin and related compounds.
SUMMARY OF THE INVENTION
[0008] The invention provides a novel compound having filamentous actin binding activity. The invention further provides a method for synthesizing the compound.
[0009] In one embodiment the invention provides a cyclomonomer having actin binding activity, the cyclomonomer comprising a heptapeptide having a cystyl residue, a prolyl residue, and a tryptophanyl residue and wherein the cystyl residue and the tryptophanyl residue are linked by a thioether bond. In a preferred embodiment the actin is filamentous actin. In another preferred embodiment the heptapeptide further comprises an amino acid residue selected from the group consisting of an alanyl residue, a leucyl residue, a glycyl residue, a threonyl residue, and a glutamyl residue. In a more preferred embodiment the amino acid residues are L-isomers. In another more preferred embodiment the amino acid residues are D-isomers. In another preferred embodiment the prolyl residue is a hydroxyprolyl residue. In a yet more preferred embodiment the prolyl residue is a protected cis-4-hydroxy-L-prolyl residue, the protection comprising a triisopropylsilyl moiety. In a most preferred embodiment the cyclomonomer is bicyclo(Ala1-D-Thr2-Cys3-cis-4-hydroxy-Pro4-Ala5-2-mercapto-Trp6-Glu7)(S-3→6).
[0010] In one embodiment, a side chain of the cyclomonomer is selected from the group consisting of hydrogen, fluoride, cyano, halogen, carboxylic acid, a salt of carboxylic acid, sulfonic acid, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, aryl, heteroaryl, -L-R X and -L-S C , wherein said alkyl or alkoxy is optionally substituted by carboxylic acid, sulfonic acid, or halogen and said aryl or heteroaryl is optionally substituted one or more times by C 1 -C 6 alkyl, C 1 -C 6 perfluoroalkyl, cyano, halogen, azido, carboxylic acid, sulfonic acid, or halomethyl, a carboxylic acid ester of a C 1 -C 6 alcohol, a C 1 -C 6 alkyl that is optionally substituted one or more times by carboxylic acid, sulfonic acid, amino, or halogen, nitro, hydroxy, azido, amino, hydrazino, -L-R X and -L-S C , C 1 -C 18 alkyl, C 1 -C 18 alkoxy, C 1 -C 18 alkylthio, C 1 -C 18 alkanoylamino, C 1 -C 18 alkylaminocarbonyl, C 2 -C 36 dialkylaminocarbonyl, C 1 -C 18 alkyloxycarbonyl, or C 7 -C 18 arylcarboxamido, R x is a reactive group; and S C is a conjugated substance.
[0011] In another embodiment the heptapeptide comprises amino acid residues selected from the group consisting of the naturally occurring amino acids and synthetic derivatives thereof.
[0012] The invention also provides a method for synthesizing a cyclomonomer having actin binding activity, the method comprising the steps of (i) providing glutamate, Fmoc, allyl ester, 2-chlorotrityl polystyrene resin, tryptophan, α-protected alanine, α-protected cis-4-hydroxy-proline, α-protected cysteine, α-protected D-threonine, (ii) α-protecting the N-terminus of glutamate using base-labile Fmoc, (iii) protecting the C-terminal of the Fmoc-protected glutamate using allyl ester to create a modified glutamate, (iv) linking the side chain of the modified glutamate to 2-chlorotrityl polystyrene resin, (v) linking the N-terminus of the modified glutamate to tryptophan using standard Fmoc chemistry thereby creating a dipeptide, (vi) elongating the dipeptide with N-α-protected alanine using standard Fmoc chemistry thereby creating a tripeptide, (vii) elongating the tripeptide with N-α-protected cis-4-hydroxy-proline using standard Fmoc chemistry thereby creating a tetrapeptide, (viii) elongating the tetrapeptide with N-α-protected, S-trityl protected cysteine using standard Fmoc chemistry thereby creating a pentapeptide, (ix) elongating the pentapeptide with N-α-protected D-threonine using standard Fmoc chemistry thereby creating a hexapeptide, (x) elongating the hexapeptide with N-α-protected alanine using standard Fmoc chemistry thereby creating a heptapeptide, (xi) removing the N-terminal Fmoc and the C-terminal allyl ester, (xii) deprotecting the heptapeptide using Pd(PPh 3 ) 4 , NMM, acetic acid, DCM, 20% piperidine, and DMF thereby creating a modified heptapeptide, (xiii) cyclizing the modified heptapeptide using diphenylphosphorylazide (DPPA), DIPEA, and DMF thereby creating a cyclomonomer, (xiv) treating the cyclomonomer with I 2 in DMF thereby creating a thioether bond between the cysteine residue and the tryptophan residue, (xv) cleaving the modified cyclomonomer from the resin using 1% TFA in CH 2 Cl 2 , the steps resulting in the synthesis of bicyclo(Ala1-D-Thr2-Cys3-cis-4-hydroxy-Pro4-Ala5-2-mercapto-Trp6-Glu7)(S-3→6).
[0013] In an alternative embodiment the method further comprises the step of elongating the tripeptide using side chain-protected cis-4-hydroxy-proline.
[0014] In another alternative embodiment the method further comprises the step of elongating the pentapeptide using side chain-protected D-threonine.
[0015] In yet another alternative embodiment the method further comprises the step of treating the modified cyclomonomer using 50% TFA in CH 2 Cl 2 .
[0016] In a still further alternative embodiment the method further comprises the step of treating the modified cyclomonomer using 50% HF in THF.
[0017] The invention also provides a method for treating a subject having the symptoms of hepato-toxicity due to ingestion of Amanita sp., the method comprising the step of providing the subject with a pharmaceutical composition comprising the cyclomonomer disclosed herein and a pharmaceutical carrier in a sufficient amount to reduce and alleviate the symptoms.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 illustrates the chemical structures of phalloidin (1) and Glu7-phalloidin (2).
[0019] FIG. 2 illustrates a process for testing solid phase 1 2 -mediated cyclization strategy using tetrapeptide model systems (scheme 1).
[0020] FIG. 3 illustrates the solid phase peptide synthesis (SPPS) strategy showing the chlorotritylchloride resin and the Fmoc protection groups and linker.
[0021] FIG. 4 illustrates the synthesis of Fmoc-cis-Hyp(OTIPS)-OH including the reagents (a) Cs 2 CO 3 , MeI; (b) PPh 3 , DIAD, 3,5-dinitrobenzoic acid; (c) NaN 3 , 15-crown-5; (d) TIPS-Cl, imidazole; and (e) LiOH, H 2 O.
[0022] FIG. 5 illustrates a standard peptide coupling reaction to synthesize the final linear sequence Fmoc-Ala-d-Thr(TBU)-Cys(trt)-Hyp(OAc)-Ala-Trp-Glu(OAII).
[0023] FIG. 6 illustrates a process for SPPS of Glu 7 -phalloidin (scheme 2).
[0024] FIG. 7 illustrates a process for conversion of Glu 7 -phalloidin to a rhodamine derivative (scheme 3).
[0025] FIG. 8 illustrates a comparison between phalloidin (1), Glu 7 -phalloidin (2), and a thioether-cyclized compound comprising a model peptide (Cys- L Pro-Ala-Trp; 3), the compound derived from the bioactive portion of phalloidin.
[0026] FIG. 9 illustrates photomicrographs showing a) BS-C-1 cells stained with fluorescent phalloidin derivative 7; b) cells pretreated with natural phalloidin 1 prior to addition of 7. Inset image shows phase contrast image of same field.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The invention disclosed herein provides phalloidin and derivatives thereof that can be used to study the effects of fungal and synthetic toxins on the cellular cytoskeleton, in particular upon actin polymerization, such as during cell division, cell proliferation, cellular and tissue differentiation, and metabolic and dynamic processes in tissue, such as those of muscle, nerve, endothelium, the blood circulatory system, and the lymphatic system.
[0028] As used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to “an amino acid residue” includes a plurality of such amino acid residues, and a reference to “a side chain” is a reference to one or more side chains and equivalents thereof, and so forth.
[0029] The naturally occurring amino acids include, but are not limited to, alanine, asparagine, aspartic acid or aspartate, cysteine, cystine, glutamine, glutamic acid or glutamate, phanylalanine, glycine, histidine, isoleucine, lysince, leucine, methionine, proline, arginine, serine, threonine, valine, tryptophan, tyrosine, and derivatives thereof. The amino acid can be an L-isomer or can be a D-isomer. The side chains of the amino acid residues can be modified, for example, by phosphorylation, sulphation, or acetylation.
[0030] In efforts to develop high-throughput cell-based screens for compounds that modulate actin cytoskeletal morphology, an inexpensive source of fluorescently labeled phalloidin has been sought.
[0031] Herein we report a solid-phase synthesis of Glu 7 -phalloidin ( FIG. 1 ; 2) in 50% overall yield from simple starting materials. Derivatization of the Glu 7 side chain yielded a fluorescent analog that stains F-actin in fixed cells at a concentration comparable to commercial phalloidin-based probes. The phalloidin derivative can be a tetrapeptide, a pentapaptide, a hexapeptide or a heptapeptide.
[0032] The natural product found in the mushroom contains four common L-amino acids, a D-threonine residue, an unusual γ,δ-dihydroxy-L-leucine residue, and the rare cis epimer of 4-hydroxy- L -proline. Since the γ,δ-dihydroxyleucine side chain is not essential for actin binding (see, for example, Falcigno, L. et al. (2001) supra) we replaced this residue with glutamic acid. This substitution provided both a handle for linking to the solid phase and a site for fluorophore attachment ( FIG. 2 ; 2, Scheme 1). The cis-4-hydroxyproline residue was prepared according to published methods and the remaining amino acids were commercially available (see, for example, Anderson, M. O. and Guy, R. K., (2005) supra; Weir, C. A. and Taylor, C. M. (1999) J. Org. Chem., 64: 1554-1558; and Weir, C. A. and Taylor, C. M. (1999) Org. Lett., 1: 787-789).
[0033] The approach herein to form the thioether bridge was inspired by a side reaction reported during I 2 -mediated deprotection of S-tritylcysteine (Cys[Trt]) in peptides containing tryptophan. (Alternatively, thionation may occur by iodination of the indole to form a 3-iodoindolenine intermediate, which undergoes nucleophilic attack on C2 by the sulfur atom followed by dehydrohalogenation.) The minor product was attributed to thioether formation between the Cys and Trp residues, which occurred presumably via attack of the tryptophan indole by a highly electrophilic sulfenyl iodide species (see Sieber, P. et al. (1980) Helvet. Chim. Acta, 63: 2358-2363). Using model peptides based on the sequence Cys(Trityl)-Gly n -Trp, Sieber et al. (1980, supra) showed that I 2 treatment led to efficient thioether formation that out-competed disulfide dimerization when n>3.
[0034] When similar conditions were applied to the solid-phase synthesis of model peptides based on the thioether-containing sequence of phalloidin, the only observed products were the desired thioether and the dimer resulting from on-resin intermolecular disulfide formation. Using the sequence H 2 N-Cys-Pro-Ala-Trp-OH, at a loading value of 0.1 mmol/g, cyclization out-competed dimerization by a 2:1 ratio ( FIG. 2 ; Scheme 1). When the L-proline residue was replaced with triisopropylsilyl (TIPS) -protected cis-4-hydroxy-L-proline, the ratio of thioether to disulfide increased to 6.6:1. These results pointed toward a solid-phase synthesis of Glu 7 -phalloidin using an I 2 -mediated cyclization strategy for the thioether bridge-forming step.
[0035] To generate the appropriate peptide precursor, the Glu 7 residue was C-terminally protected as an allyl ester and linked through its side chain to 2-chlorotrityl polystyrene resin (see FIG. 3 ). The heptapeptide was elongated using standard Fmoc chemistry ( FIG. 5 ; Scheme 2), and after removal of the N-terminal Fmoc and C-terminal allyl ester, the peptide backbone was cyclized using diphenylphosphorylazide (DPPA). Cleavage from the resin and high pressure liquid chromatography-mass spectroscopy (HPLC-MS) analysis showed that the macrolactamization proceeded efficiently. No cyclodimer or higher oligomers were observed.
[0036] It should be noted that initial attempts to remove the final Fmoc group using 20% piperidine in dimethylfluoride (DMF) resulted in the formation of unidentified side-products and a low overall yield of Glu 7 -phalloidin. Treatment of the linear peptide with 1% diazabicycloundecane (DBU) in DMF, however, afforded clean deprotection of the N-terminus and led to a dramatic increase in yield of the final product.
[0037] When resin-bound cyclic peptide 4 was treated with I 2 in DMF, we observed complete conversion to thioether with no intermolecular disulfide dimer detected ( FIG. 6 ; Scheme 2). Cleavage from the resin was performed with 1% trifluoroacetic acid (TFA)/CH 2 Cl 2 , followed by removal of the D-Thr and 3-hydroxyproline side chain protecting groups using 1:1 TFA/CH 2 Cl 2 and then 50% HF-pyridine/THF. HPLC purification yielded two isomeric compounds in a 1:1 ratio whose circular dichroism (CD) and 1 H NMR spectra were consistent with the natural (2) and “unnatural” (5) atropisomers of phalloidin. The overall yield of the purified material was 50% based on the initial resin loading.
[0038] It is noted that synthetic phallotoxins can exist as two isolatable atropisomers. The synthetic route reported here accesses the natural atropisomer exclusively, as determined by comparison of the CD spectrum of Glu 7 -phalloidin to that of the authentic natural product. In addition, the distinctive upfield chemical shift of the Ala 5 methyl group is diagnostic of the natural atropisomer, due to its proximity to the anisotropy field of the tryptophan indole ring (see Anderson, M. O. et al., (2005) J. Org. Chem. 70: 4578-4584).
[0039] The ability to select atropisomers in bridged cyclic structures by changing the order of cyclization has been exploited in syntheses of the natural product vancomycin (see, for example, Boger, D. L. et al.(2001) J. Am. Chem. Soc. 123: 1862-1871; Boger, D. L. et al. (1999) J. Am. Chem. Soc. 121: 10004-10011; Nicolaou, K. C. et al. (1999) Chemistry—A European Journal, 5: 2622-2647; and Boger, D. L. et al. (1999) J. Am. Chem. Soc., 121: 3226-3227). We therefore investigated whether formation of the thioether bridge prior to macrolactamization would result in a different ratio of atropisomers. Removal of the allyl ester from resin-bound linear peptide 3 followed by I 2 treatment provided the monocyclic thioether 6 quantitatively ( FIG. 7 ; Scheme 3). Fmoc deprotection and macrolactamization with DPPA yielded a single major product that was ˜80% pure by LC/MS. None of the non-natural atropisomer was detected. Side chain deprotection and purification by reversed phase HPLC provided Glu 7 -phalloidin (2) in 28.5% overall yield based on initial resin loading.
[0040] Conjugation of tetramethylrhodamine-cadaverine to compound 2 was effected using HBTU in dimethylsulfoxide (DMSO), yielding fluorescent adduct 7 ( FIG. 7 ). When cultured mammalian epithelial BS-C-1 cells were fixed and treated with 7 at 20 nM followed by extensive washing, fluorescence microscopy revealed the F-actin staining pattern typical of commercially available phalloidin conjugates ( FIG. 9 ). Actin filament staining was completely abolished when the fixed cells were pretreated with natural phalloidin, demonstrating the specificity of 7 for F-actin (see FIG. 9 ( b ): absence of stain/no image; the inset shows phase contrast image of same field of view showing presence of cells).
[0041] Compositions that can be used to label a compound for detecting the presence or absence of the compound when present in a cell or tissue, or when it is bound to a sub-cellular structure or compound, such as to filamentous actin, include, but are not limited to a fluorescent dye, such as, fluorescein, rhodamine, Texas Red, VECTOR Red, ELF™ (Enzyme-Labeled Fluorescence), Cy0, Cy0.5, Cy1, Cy1.5, Cy2, Cy3, Cy3.5, Cy5, Cy7, FluorX, Calcein, Calcein-AM, CRYPTOFLUOR™, Orange (42 kDa), Tangerine (35 kDa), Gold (31 kDa), Red (42 kDa), Crimson (40 kDa), BHMP, BHDMAP, Br-Oregon, Lucifer Yellow, Alexa dye family, N-[6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]caproyl] (NBD), BODIPY™, boron dipyrromethene difluoride, Oregon Green, MITOTRACKER™ Red, DiOC 7 (3), DiIC 18 , Phycoerythrin, Phycobiliproteins BPE (240 kDa) RPE (240 kDa) CPC (264 kDa) APC (104 kDa), Spectrum Blue, Spectrum Aqua, Spectrum Green, Spectrum Gold, Spectrum Orange, Spectrum Red, NADH, NADPH, FAD, Infra-Red (IR) Dyes, Cyclic GDP-Ribose (cGDPR), Calcofluor White, Tyrosine, Tryptophan, ATTO labels (Sigma-Aldrich, St. Louis Mo.), RED MEGA labels (Sigma-Aldrich, St. Louis Mo.), and Phycobili proteins, FDNB, FNBT, TNBS, ninhydrin, DABS-Cl, OPA, NDA, fluorescamine, MDF, DNS-Cl, Fmoc-Cl, PITC, radio-active isotopes, and any chemical derivatives thereof., and a non-fluorescent dye, such as, alkaline phosphatase, horseradish peroxidase, glucose oxidase and beta-galactosidase substrate. These labeling compositions can be conjugated to the compound using methods well known to those of skill in the art. Such methods include but are not limited to, fluorescent microscopy, phospho-imaging, scintillation counting, and the like.
[0042] Use of Alternative Peptide Substrates
[0043] Since the major competing reaction to thioether formation is disulfide dimerization, it was reasoned that transfer of the 1 2 -mediated Cys-Trp coupling from solution to the solid phase under low-loading conditions might favor intramolecular cyclization over intermolecular disulfide bond formation. A loading value of ˜0.1 mmol/g resin was found to be low enough to minimize disulfide formation for a range of sequences, while still providing enough material to make the reaction practically feasible. A tetrameric model peptide based on the palloidin-derived sequence Cys(Trt)-Pro-Ala-Trp reacted with I 2 to form the thioether-cyclized product (3) in good overall yield, foreshadowing a successful Trp-Cys couplin in the synthesis of the bicyclic phalloidin scaffold (see FIG. 8 ).
[0044] Expanded structure-activity studies on the phalloidin-actin interaction and evaluation of the generality of this new peptide cyclization strategy using I 2 -mediated thioether cyclization in the synthesis of cyclic peptides containing the general Cys-Xaa n -Trp motif were performed. Table 1 shows the experimental compound number (column 1), the peptide sequence therein (column 2), and the thioether:disulfide ratio (column 3).
TABLE 1 Ratio of intramolecular thioether formation to intermolecular disulfide formation as a function of sequence. compound peptide thioether:disulfide ratio 3 Cys-LPro-Ala-Trp 2.5:1 4 Cys-LPro-Leu-Trp 3.1:1 5 Cys-LPro-Gly-Trp 5:1 6 Cys-DPro-Gly-Trp Exclusive disulfide 7 Cys-DPro-Ala-Trp 0.14:1 8 Cys-DPro-Leu-Trp 1.26:1 9 Cys-LPro-DAla-Trp 7.5:1 10 Cys-Gly-LPro-Trp Exclusive disulfide 11 Cys-Leu-LPro-Trp Exclusive disulfide 12 Cys-Gly-DPro-Trp Exclusive disulfide 13 Cys-Leu-DPro-Trp 1.2:1 14 Cys-cis-Hyp(OTIPS)-Ala-Trp 8.3:1 15 Cys-cis-Hyp(OTIPS)-Leu-Trp 8.1:1 16 Cys-trans-Hyp(OH)-Leu-Trp Exclusive monomer 17 Cys-trans-Hyp(OTIPS)-Leu-Trp 3:1 18 Cys-Gly-Gly-Trp Exclusive disulfide 19 Cys-Ala-Ala-Trp 1.2:1 20 Cys-Leu-Leu-Trp 3.8:1 21 Cys-Leu-Leu-Leu-Trp 0.63:1 22 Cys-Gly-LPro-Leu-Trp 10:1 23 Cys-LPro-Gly-Leu-Trp Exclusive monomer 24 Cys-Leu-Trp 0.7:1 25 Cys-Leu-Leu-Leu-Leu-Trp 1:1 26 Cys-Leu-Leu-Leu-Leu-Leu-Trp Exclusive monomer Note to Table 1: The thioether monomer and the corresponding disulfide dimer for sequence 4 were fully characterized by 2D 1 H and 13 C NMR and HRMS. Ratios were determined by integrating the light scattering signal using LC/MS, based on standard curves using known amounts of 4 (monomer and dimer). # In all cases, the dimer was easily resolved from the thioether monomer. Dimers for several compounds were verified by on-resin reduction with PBu 3 and capping with iodoacetamide. Isolated yield for sequence 4 (monomer + dimer) was 17%. The average purity for all samples by LC/MS was 91% (s.d. 9%).
[0045] In particular, cyclization efficiency was measured as a function of sequence length, composition, and C a stereochemistry. The Fmoc group was retained at the amino terminus to allow for further sequence elongation and entry into more complex lariat-type structures. The major products in nearly all the sequences tested were cyclic thioether and dimeric disulfide, with average post-cleavage purities of 91% (monomer+dimer). Isolated yields on the highly acid labile 2-chlorotrityl resin were lower than expected (17% for sequence 4, monomer+dimer), with the loss ocurring at the 1 2 -mediated cyclization step. Yields did not substantially increase, however, when the less labile Rink amide resin was used in place of the 2-chlorotrityl resin (see Schuresko et al. (2007) Org. Lett.in press).
[0046] The first sequences that we investigated were tetrapeptides of the sequence H 2 N-Cys-Pro-Xaa-Trp-OH, where the stereochemistry of the proline and Xaa residues, and the side chain bulk of Xaa, were varied. In phalloidin ( FIGS. 1 and 8 ; 1), the Xaa residue is L -alanine, with a relatively small methyl group. In model peptide 3 (Table 1), L -alanine in the i+2 position yielded a 2.5:1 ratio of thioether monomer to disulfide dimer. As disclosed herein, residues are numbered according to the standard numbering scheme for b-turns; for the tetrapeptides reported in this study, Cys=i and Trp=i+3. When L -alanine was replaced with L-leucine (Table 1, peptide 4), the ratio shifted slightly in favor of the thioether monomer, with an average ratio of 3.1:1 monomer to dimer. When the i+2 residue was replaced with glycine to provide the turn-promoting Pro-Gly sequence found in peptide 5, the ratio increased further to 5:1 in favor of the monomer.
[0047] With D-proline in the i+1 position, the resulting series of peptides (peptides 6-8) displayed, on average, much lower cyclization efficiencies than their L -proline-containing diastereomers. The most striking difference was between Cys- L Pro-Gly-Trp (5) and Cys- D Pro-Gly-Trp (6), in which the L -proline isomer 5 gave a 5:1 ratio of monomer to dimer, while the D -proline isomer 6 gave exclusive disulfide dimer. Molecular modeling studies predicted that 5 takes on a type II β-turn conformation, while 6 adopts a type I′ β-turn, consistent with reported observations for known L Pro-Gly- and D Pro-Gly-containing sequences (see Karle, I. L. and Urry, D. W. (2005) Biopolymers 77: 198-204; Karle, I. et al. (2002) Proc. Natl. Acad. Sci., 99: 5160-5164; Raghothama, S. R. et al. (1 998) J. Chem. Soc., Perkin Trans. 2: 137-144; and Haque, T. S. et al. (1996) J. Am. Chem. Soc., 118: 6975-6985). The type II turn predicted for 5 brings the tryptophan indole and cysteine sulfhydryl into close proximity, while the type I′ turn in 6 causes the cysteine sulfhydryl to twist away from the indole ( FIG. 2 ), thus disfavoring cyclization.
[0048] Further support for the hypothesis that β-turn preference is a primary determinant of thioether formation in the Cys- L Pro-Xaa-Trp series is offered by a comparison of the cyclization efficiencies of 5 (Cys- L Pro-Gly-Trp, 5:1), 3 (Cys- L Pro-Ala-Trp, 2.5: 1), and 9 (Cys- L Pro- D Ala-Trp, 7.5:1). The i+2phi and psi dihedrals in type II turns correspond to an allowed region for glycine in the classic Ramachandran plot, and are also part of the “inverted α” region of the Ramachandran plot for D -amino acids (Hutchinson, E. G. and Thornton, J. M. (1994) Prot. Sci., 3: 2207-2216; and Mitchell, J. B. and Smith, J. (2003) Proteins, 50: 563-571). Indeed, the sequence L Pro- D Xaa is known to preferentially adopt a type II β-turn even in the context of short peptide sequences (Imperiali, B. et al. (1992); J. Am. Chem. Soc., 114: 3182-3188; and Boussard, G. et al. (1974) J. Chim. Phys. 71: 1081-1091). Thus, the favorable effect of D -alanine at the i+2 position is consistent with the formation of a type II β-turn in the transition state of the cyclization reaction.
[0049] The effect of D - and L -proline in the i+2 position was explored in peptides 10-13. The two sequences with L-proline at i+2, 10 and 11, both yielded the intermolecular disulfide dimer as the sole product. The two compounds with D-proline in the i+2 position, 12 and 13, gave different results depending on the identity of the i+1 residue. Sequence 12, with glycine in the i+1 position, reacted exclusively to form disulfide dimer, while 13, with leucine at i+1, gave a 1.2:1 ratio of monomer to dimer. L -Proline can occupy the i+2 position of a type VI turn, in which the proline ω dihedral adopts the cis amide geometry (see Muller, G. et al. (1993) Proteins, 15: 235-251). Although the (i)-(i+3) distance (corresponding to the cysteine and tryptophan side chains) is short in the type VI β-turn, this turn is rare in proteins and is primarily found in relatively constrained cyclic peptides (Muller (1993) supra; and Wilmot, C. M. and Thornton, J. M (1988) J. Mol. Biol., 203: 221-232). D -Proline, with a phi angle of +60°, is not found at the i+2 position of any standard turn type. Thus, thioether formation can occur even in the absence of classic turn-promoting sequences and may yield interesting scaffolds in compounds based on the Cys-Xaa- D Pro-Trp motif.
[0050] Phalloidin contains an unusual cis-4-hydroxyproline (cisHyp) residue, which was protected as a triisopropylsilyl (TIPS) ether in the synthesis of Glu 7 -phalloidin as diclosed herein. The presence of the TIPS-protected hydroxyl group in the cis configuration (14 and 15) led to a significant improvement in cyclization effiency compared with the corresponding non-hydroxylated sequences (3 and 4). Peptide 16 (Cys-trans-Hyp(OH)-Leu-Trp), in which the trans hydroxyl group was unprotected, showed exclusive formation of cyclic thioether, compared to 3:1 (monomer:dimer) for 17 and 8.1:1 for 15. Of note, these distal modifications to the proline ring may have a significant long-range effect on the outcome of the macrocyclization reaction; however, we were not yet able to account for these observations using the same modeling approach applied to 5 and 6 above.
[0051] Exploring cyclization efficiency in peptides without proline (18-21), the steric bulk of the i+1 and i+2 residues had a significant impact on cyclization. Sequence 20 (Cys-Leu-Leu-Trp) gave cyclomonomer in a 3.8:1 ratio, while 19 (Cys-Ala-Ala-Trp) dropped to 1.2:1 and 18 (Cys-Gly-Gly-Trp) gave the disulfide dimer product exclusively. In these cases, entropy may be the major factor, in which the bulkier side chains limit the degrees of freedom in the linear precursor such that cyclization outweighs disulfide formation even in the absence of a well-defined turn structure.
[0052] Insertion of an additional leucine residue (21, Cys-Leu-Leu-Leu-Trp) yielded a significant decrease in cyclization efficiency compared to tetrapeptide 20 (Cys-Leu-Leu-Trp). However, placement of L -proline within the pentamer sequences caused a dramatic increase in cyclization efficiency. Insertion of a glycine between cysteine and L -proline resulted in a significant increase in monomer formation, from 3.1:1 in 4 to 10:1 in 22. This could be due to the ˜10-fold higher preference for glycine over cysteine in the i position of type II turns (Hutchinson, E. G. and Thornton, J. M. (1994) supra), or it could reflect a general length dependence in the cyclization reaction. Support for the latter is provided by a comparison between 23 and 5, in which insertion of a leucine residue after the turn promoting L Pro-Gly sequence dramatically improved the cyclization efficiency (from 5:1 in 5 to >100:1 in 23). Interestingly, removal of a leucine residue to generate tripeptide 24 lowered the cyclization efficiency relative to tetrapeptide 20, while longer sequences such as 26 and 27 provided highly efficient access to cyclomonomer.
[0053] Thus, an I 2 -mediated Cys-Trp thioether formation into a mild solid phase cyclization strategy has been developed. Investigations into the effect of peptide sequence, stereochemistry, and length on the reaction have revealed that although turn-promoting sequences significantly enhance cyclization, the reaction is also relatively efficient even among sequences with no known β-turn propensity. The chemistry is general and mild enough to be applied, in principle, toward the synthesis of cyclic peptide libraries based on the Cys-Trp thioether linkage.
[0054] In summary, we have developed a simple synthesis of Glu 7 -phalloidin and its derivatives, including a fluorescent bioactive probe that is as effective as natural phalloidin conjugates in staining F-actin in fixed cells. This route will generate sufficient amounts of fluorescently labeled phalloidin to perform high-throughput image-based screens for compounds that affect actin morphology, and will allow us to make extensive modifications to the phalloidin scaffold for future structure-activity studies.
[0000] Binding Assay for Cyclomonomer
[0055] Saturability in the binding of a cyclomonomer demonstrates the existence of a limited number of binding sites and is the hallmark of specificity. Saturability is demonstrated if binding of a labeled cyclomonomer can be serially reduced by increasing quantities of the native, unlabeled cyclomonomer. Such data also demonstrate that the labeled cyclomonomer remains sufficiently bio-relevant that its distribution is a valid report of the distribution of the unlabeled molecule. Biological processes are time- and temperature-dependent, for example, crossing a barrier such as the plasma membrane. In particular, at low temperatures (cells held over ice) endosomal traffic would be halted, but permeation through pores or channels could continue, albeit more slowly.
[0056] The substrate used for binding thereto is preferably filamentous actin (F-actin), but can also be a synthetic peptide having similar chemical and/or biochemical properties as F-actin, it can be globular actin (G-actin), or it can be any derivatives thereof.
[0057] The present invention has now been described in accordance with several exemplary embodiments, which are intended to be illustrative in all aspects, rather than restrictive. Thus, the present invention is capable of many variations in detailed implementation, which may be derived from the description contained herein by a person of ordinary skill in the art.
[0058] While the above is a complete description of the preferred embodiments of the invention, various alternatives, modifications, and equivalents may be used. Therefore, the above description should not be taken as limiting the scope of the invention which is defined only by the claims and any amendments thereto.
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The invention provides a cyclomonomer having actin-binding activity. The cyclomonomer is of utility for the study of the molecular biology of actin polymerization. The cyclomonomer is also useful for the study of and treatment of the toxic effects of Amanita sp. poisoning.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to record playing apparatus, and, more particularly, to apparatus for adjusting and displaying the stylus pressure exerted on a record disc by a stylus carried by a tone arm in a record playing device while the information which is recorded on the record disc is being reproduced.
2. Description of the Prior Art
In most record players, such as phonograph record players wherein sound information is reproduced by a stylus which tracks pre-recorded sound grooves, a stylus pressure-adjustment mechanism is provided to enable the user to adjust the pressure which is exerted on the record disc by the stylus. While stylus pressure must be sufficient to keep the stylus in the groove which is tracked, it must not be so great as to limit free movement and reduce the longevity of the stylus. Generally, stylus pressure is set and adjusted by a weight coupled to the rear end of the tone arm, that is, the end which is remote from the stylus, and the stylus pressure setting is indicated by direct mechanical measurement, that is, by a scale proximate the weight. As the precise position of the weight along the tone arm is adjusted, the stylus pressure is changed. A significant disadvantage in record playing devices of this kind, however, is that actual stylus pressure can not be readily ascertained or adjusted while a reproducing operation is in process, that is, while the stylus is in contact with the record disc. Rather, the reproducing operation must be interrupted and then, while the record playing device is in its quiescent condition, the actual stylus pressure can be changed. It has been proposed to move the tone arm of a recording playing device in the vertical direction by a vertical drive motor. In such a record playing device, selective energization of the vertical drive motor results in lowering the tone arm onto the surface of the record disc in order to initiate a reproducing operation, and lifting the tone arm at the completion of such a reproducing operation. That is, a current flowing through the vertical drive motor acts to control the vertical movement of the tone arm.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide improved apparatus for electronically adjusting and displaying the stylus pressure exerted on a record disc by a stylus carried by a tone arm in a record playing device.
More particularly, it is an object of this invention to provide selective energization of a vertical drive motor normally used to drive the tone arm in a vertical direction, in order to adjust the stylus pressure.
It is another object of this invention to provide apparatus for displaying the energizing current level of the aforementioned vertical drive motor so as to provide a direct display of stylus pressure.
It is still another object of this invention to provide apparatus for use in a record player in which the stylus pressure exerted on the record disc can be easily adjusted and displayed, even while the record player is in the process of carrying out a reproducing operation.
It is yet another object of this invention to provide an electronic display of the stylus pressure which is exerted and a record disc and preferably in a digital manner.
It is a further object of this invention to provide apparatus for displaying the stylus pressure in a record playing device and for exerting a stylus pressure on a record disc which correctly corresponds to the displayed stylus pressure.
In accordance with this invention, apparatus for adjusting and displaying the stylus pressure exerted on a record disc by a stylus carried by a tone arm in a record playing device comprises a vertical drive motor which bi-directionally drives the tone arm in the vertical direction, an adjustable element, such as a variable resistor, producing a control signal whose level is established by the setting of the adjustable element, and which is determinative of the stylus pressure, an energizing circuit responsive to the control signal for energizing the vertical drive motor in accordance with the level of the control signal, thereby establishing the stylus pressure, and a display device, such as a digital numerical display, responding to the control signal for providing a visual display of the stylus pressure as determined by the level of the control signal. In accordance with one aspect of this invention, the control signal, which is an analog signal derived from the adjustable element, is converted to a digital representation, and this digital representation is displayed. In one embodiment, the digital representation is re-converted back to an analog signal, and this re-converted analog signal is supplied to the energizing circuit and used therein for energizing the vertical drive motor. This avoids quantizing errors between the displayed stylus pressure and the actual stylus pressure.
The above, and other objects, features and advantages of this invention will be apparent in the following detailed description of illustrative embodiments which are to be read in connection with the accompanying drawings.
CL BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a record playing device in which the present invention finds ready application;
FIG. 2 is top view of a portion of the apparatus shown in FIG. 1;
FIG. 3 is a cross-sectional view taken along line III--III of FIG. 2;
FIG. 4 is a partial block, partial schematic diagram of one embodiment of the present invention;
FIG. 5 is a partial block, partial schematic diagram of another embodiment of this invention; and
FIG. 6 is a graphical representation which is useful in understanding the advantages attained by the embodiment shown in FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and initially to FIGS. 1 and 2, there is illustrated a type of record playing device in which the present invention finds ready application. This device includes a rotatable shaft 3 supported by a bearing block 2 which is, in turn, supported on a support member 1, such as a support panel or frame upon which a turntable 30 also is supported. A tone arm 4 is mechanically coupled to the upper end of rotatable shaft 3 by means of a pivot axis or shaft 5 whereby tone arm 4 is adapted to move in the vertical and horizontal directions. That is, in the horizontal direction, tone arm 4 rotates with shaft 3 about the vertical axis of the latter and tone arm 4 further is adapted to pivot in the vertical direction about pivot axis 5. For the present discussion, the "horizontal direction" means a direction parallel to the surface of record disc 31 with which the illustrated record playing device is used, and the expression "vertical direction" is perpendicular to this horizontal direction. At one end of tone arm 4, referred to herein as the forward end, a cartridge support element, or head shell 6 is provided and a cartridge having a stylus 8 extending downwardly therefrom, is mounted to this head shell. It is appreciated that, when tone arm 4 pivots about pivot axis 5 in the vertical direction, head shell 6, together with cartridge 7 and stylus 8, moves in the vertical direction either to be placed upon record disc 31 or to be lifted therefrom, as represented by the illustrated arrows. A counter weight 9 is mounted to the rearward or tail end of tone arm 4, that is, the end which is remote from head shell 6, as is conventional, for balance.
A horizontal drive motor 11 is mechanically coupled to shaft 3 and is adapted to drive the shaft such that it rotates about a vertical axis and, thus, correspondingly drives tone arm 4 in the horizontal direction. Horizontal drive motor 11 includes source of magnetic flux, such as an arcuate permanent magnet 12 which is curved about shaft 3 and secured to a yoke assembly, and a drive coil 13 which is adapted to be driven or rotated, together with shaft 3 bi-directionally about the vertical axis of the latter in parallel with the upper surface of permanent magnet 12, as represented by arrows b and b' (FIG. 2). The yoke upon which permanent magnet 12 is supported is comprised of, for example, a yoke member 15 upon which the permanent magnet is mounted, and a yoke member 18, members 15 and 18 being provided as congruent arcuate segments which are spaced apart from each other. Yoke member 15 terminates in upstanding members at its opposite ends to which yoke member 18 is joined. Hence, permanent magnet 12 together with yoke members 15 and 18 comprise a magnetic circuit in which the magnetic flux is generated in the upward direction from yoke member 15 toward yoke member 18, as viewed in FIG. 1. The yoke assembly, comprised of yoke members 15 and 18, is secured to bearing block 2 by an arm 14, as shown more clearly in FIG. 2. Hence, since the bearing block is fixed against rotation, it is appreciated that the yoke assembly likewise remains stationary relative to the rotation of shaft 3.
Drive coil 13 is wound about a bobbin 17 whose central opening receives yoke member 18. Bobbin 17 is coupled to shaft 3 by an arm 16 such that drive coil 13 is movable along yoke member 18, yet is properly spaced therefrom so as to avoid contact with this yoke member. Drive coil 13 is adapted to be supplied with an energizing current which may flow through coil 13 in either of two directions, represented by arrows a and a' in FIG. 2, and which intersects with the magnetic flux at right angles. Thus, a drive force in the direction shown by arrow b or b' in FIG. 2 is imparted to coil 13 to drive tone arm 4 in the lead-in direction or the lead-out direction depending upon the direction of current through coil 13. That is, when energizing current is supplied in the direction of arrow a, the interaction between this current and the magnetic flux in which drive coil 13 is disposed results in a force in the direction of arrow b. Conversely, when an energizing current is supplied to drive coil 13 in the direction indicated by arrow a', a force is produced in the direction of arrow b'. Coil 13, together with bobbin 17 about which the coil is wound, is displaced along yoke member 18 by reason of these forces b and b'. As coil 13 is displaced, arm 16 rotates so as to correspondingly rotate shaft 3 to which this arm is secured. Thus, it is seen that tone arm 4 bi-directionally rotates in the horizontal direction as a result of the energizing currents which are supplied to drive coil 13 of horizontal drive motor 11. Further, the drive force imparted to coil 13 increases with the intensity of current flowing through coil 13, although such drive force is constant for any given intensity of current.
A vertical drive motor 20 is coupled to the rearward, or tail end, of tone arm 4 and, in principle, is similar in operation to that of horizontal drive motor 11. As shown in FIG. 3, the vertical drive motor includes a magnetic circuit comprised of a yoke assembly 22 and a pair of oppositely poled permanent magnets 23. Yoke assembly 22 is formed of side walls which, as shown in FIG. 1, are arcuately shaped, the inner surfaces of these side walls, that is, the surfaces which are in face-to-face relationship with each other, having permanent magnets 23 secured thereto, as by a suitable adhesive. Yoke assembly 22, which is constructed of a magnetically permeable material, also includes a centrally disposed member 27. When viewed in FIG. 3, the magnetic flux generated by permanent magnets 23 extends from one to the other magnet transversely of center member 27. Yoke assembly 22 is coupled to shaft 3 by a support arm 21 and, therefore, is rotatable in the horizontal direction with the shaft and, thus, with tone arm 4. Arm 21 is fixed against vertical movement and, consequently, yoke assembly 22 likewise remains fixed against such vertical movement.
Vertical drive motor 20 additional includes a bobbin 25 whose opening receives central member 27, as shown in FIG. 3. A drive coil 26 is wound on bobbin 25 and thus, is disposed in the magnetic flux generated between permanent magnets 23. A mounting frame 24 is secured to bobbin 25, and this mounting frame additionally is coupled to tone arm 4. In addition, weight 9 is fixed to the tail end of tone arm 4 by mounting frame 24. The direction of energizing current flowing through drive coil 26 is normal to the direction of the magnetic flux. Hence, drive A vertically directed drive force in vertical direction shown by arrow c or c' in FIG. 1 is imparted to tone arm 4 due to the interaction between this energizing current and the magnetic flux so as to drive tone arm 4 in the vertical direction. The direction of this force (i.e., up and down) is dependent upon the direction in which the energizing current flows through drive coil 26. Thus, if coil 26 is energized so as to rotate in the direction of arrow c, tone arm 4 is pivoted about pivot axis 5 so as to lower stylus 8 onto the surface of record disc 31. Conversely, if coil 26 is energized so as to pivot in the direction of arrow c' about pivot axis 5, tone arm 4 is rotated so as to lift stylus 8 from the surface of the record disc.
The above described tone arm 4 is thus moved in the horizontal direction with respect to a record disc 31 on a turntable 30 by horizontal drive motor 11, and is also moved in the vertical direction with respect to the record disc by vertical drive motor 20. It will be understood that the respective motors are supplied with electric power from respective motor control drive circuits in order to control the horizontal and vertical movement of tone arm 4.
In the apparatus according to this invention, vertical drive motor 20 for tone arm 4 is utilized to apply a desired stylus pressure to record disc 31 and the value of this stylus pressure is displayed in a display circuit. That is, it is seen that if the energizing current supplied to drive coil 26 is varied so as to increase the force exerted on the drive coil in the direction of arrow c, the pressure exerted by stylus 8 on record disc 31 is increased. Conversely, if this force on coil 26 is reduced, or if a counter force is produced in the direction of arrow c', the pressure exerted on record disc 31 by stylus 8 is correspondingly reduced. This feature is turned to account by the present invention, wherein an electronic circuit is provided to adjust the stylus pressure exerted on the record disc by stylus 8. One embodiment of such an electronic circuit is illustrated in the partial block, partial schematic diagram of FIG. 4. This circuit is comprised of a drive circuit 40 connected to drive coil 26 of vertical drive motor 20 for adjusting the stylus pressure. Although drive circuit 40 may be included in the overall motor drive circuit which is provided for coil 26, it is illustrated herein as a separate circuit in order to facilitate a ready understanding of the present invention. Drive circuit 40 is comprised of an operational amplifier 40a having inverting and non-inverting inputs. The operational amplifier 40a is connected at its non-inverting input to a reference potential, such as ground, and is connected at its inverting input through a resistor 41 to an adjustable element, such as a variable resistor 42, which supplies a control voltage thereto for setting a desired stylus pressure. Variable resistor 42 is connected across a source of operating voltage +B so as to produce the desired control voltage. The inverting input of amplifier 40a is also connected through a resistor 43 to the output of amplifier 40a which, together with resistor 41, establishes the gain of operational amplifier 40a. However, although operational amplifier 40a is connected as a so-called inverting amplifier, it will be appreciated by those of ordinary skill in the art that, if desired, the operational amplifier may be connected as a non-inverting amplifier. Further, the output of operational amplifier 40a is connected to drive coil 26 of vertical drive motor 20 to supply an energizing current thereto as a function of the setting of variable resistor 42. A junction point between the slidable contact of variable resistor 42 and input resistor 41 of drive circuit 40 is connected via the slidable contact of a variable resistor 44. To a display circuit 50 for displaying a detected digital signal corresponding to the stylus pressure. Variable resistor 44 serves as a display calibration resistor to match the magnitude of the control voltage derived from variable resistor 42 with the amplitude parameters of display circuit 50. The display circuit 50 is comprised of, for example, an analog-to digital (A/D) converter 51, a decoder 52, a driving circuit 53 and a digital indicator 54. A/D converter 51 may be of conventional construction and is adapted to produce a digital representation of the control voltage supplied thereto from variable resistor 42.
In operation, the control voltage which is established by the setting of variable resistor 42 is supplied to the inverting input of operational amplifier 40a via resistor 41. If the resistance value of the resistor 41 is given as R i and a current flowing through this resistor 41 is given as i, a control voltage e at the slidable contact of variable resistor 42 can be expressed as follows:
e=R.sub.i ×i
From the above equation, it should be noticed that the desired stylus pressure is proportional to the current i and control voltage e. Accordingly, as the value of variable resistor 42 is changed, an energizing current having a value corresponding to the input current i of drive circuit 40 is supplied to drive coil 26 so as to achieve a desired stylus pressure setting. Thus, if the setting of the variable resistor is such as to produce a control voltage having a relatively higher level, the stylus pressure exerted on record disc 31 (FIG. 1) likewise is relatively higher. Conversely, if the setting of variable resistor 42 results in a control voltage of a relatively lower level, the stylus pressure likewise is at a correspondingly lower level. Thus, the pressure exerted on record disc 31 by stylus 8 is determined by the control voltage which is established by the setting of variable resistor 42.
Further, a current proportional to the input current of drive circuit 40 is supplied to variable resistor 44 so as to generate the control voltage corresponding to the stylus pressure. This control voltage, as established by the setting of variable resistor 42, is thus also supplied through resistor 44 to A/D converter 51 where it is converted to a corresponding digital signal or representation, which is then decoded by decoder 52. This decoded representation is then supplied through driving circuit 53 to digital indicator 54. Consequently, the level of the control voltage, which is seen to represent a level of the stylus pressure, is displayed. Preferably, the digital display is calibrated such that the control voltage derived from variable resistor 42 is displayed as a corresponding stylus pressure in terms of grams. If, while the record playing device is in use, that is, while the record playing device is reproducing the information recorded on record disc 31, the user wishes to change the stylus pressure, he need merely adjust variable resistor 42 so as to change the control voltage derived therefrom. This change in the control voltage effects a corresponding change in the stylus pressure. Also, as this control voltage is changed, the indication of stylus pressure, as displayed by digital display 54, likewise is changed so as to reflect the new pressure which has been selected by the operator. In the stylus-pressure adjusting and displaying circuit described above, although the actual stylus pressure applied by the driving force of the motor is an analog value, the display circuit displays the stylus pressure in digital form. Assuming that the stylus pressure is displayed for every 0.1 gram of change, a maximum display error of ±0.05 gram may result with respect to the actual stylus pressure. This means that, although the control voltage which is derived from variable resistor 42 may change by less than 0.1 gram, this change in the control voltage will not be reflected in a change in the numerical indication displayed by digital display 54 and, the displayed stylus pressure may therefore differ from the actual stylus pressure by this error. Nevertheless, such a small error in the displayed stylus pressure will have little, if any, effect on the overall performance of the illustrated apparatus.
The reason for the aforementioned display error is due to the fact that variable resistor 42 may be varied continuously, whereas the digital representation produced by A/D converter 51 varies in a step-wise manner. Accordingly, it is possible to reduce this display error by using a stepwise variable resistor in place of the continuously variable resistor 42. Hence, each change in the setting of such a step-wise variable resistor will result in a discrete, or step-wise, change in the control voltage to which A/D converter 51 will respond. With this arrangement, however, the resistance value for each step of the variable resistor must be highly accurate. Furthermore, since mechanical apparatus is relied upon for changing the setting of the stepwise variable resistor, there must be no loss due to this mechanical apparatus.
The aforementioned display error is overcome by the embodiment illustrated in FIG. 5. In this embodiment, the same drive circuit 40 is used to supply an energizing current to drive coil 26 so as to establish the stylus pressure exerted on record disc 31 by stylus 8. Also, a control voltage with its level being continuously adjusted is derived from a variable resistor 60 similar to aforedescribed variable resistor 42, for adjusting the stylus pressure. This control voltage is supplied to an A/D converter 62 and a setting change detector 63.
A/D converter 62 may be similar to aforedescribed A/D converter 51 and functions to convert the analog control voltage from variable resistor 60 into a digital signal or representation, such as a binary coded signal. As the setting of the variable resistor is changed, the level of the control voltage correspondingly changes so as to effect a change in the digital representation produced by the A/D converter digital. This representation is supplied to a latch circuit 64 to be stored therein. Setting change detector 63 is adapted to detect the absence of any change in the level of the control voltage from variable resistor 60. This absence of any change causes detector 63 to trigger latching circuit 64 to latch, or store, the digital representation produced by A/D converter 62. Thus, it is seen that the purpose of the combination of setting change detector 63 and latching circuit 64 is to prevent the latching circuit from storing a digital representation of a changing control voltage. It is only when the desired control voltage is reached, that is, once the adjustment operation has been completed, that latching circuit 64 stores the digital representation thereof. When another adjustment operation is initiated, latching circuit 64 is inhibited from storing the changing digital representation which is produced by A/D converter 62 in response to the changing control voltage.
The stored digital representation from latch circuit 64 is supplied to a D-A converter 65 and a decoder 66, respectively. The decoder 66 converts the above digital representation control signal into, for example, a 7-segment decimal code. And the output of decoder 66 is fed to a driving circuit 67 to thereby drive a digital indicator 68 which may be, for example a, 7-segment display, resulting in a visual numerical indication. D/A converter 65 converts the stored digital control signal into an analog control signal having a level corresponding to the digital control signal. This analog representation is supplied to drive circuit 40 for adjusting the stylus pressure. That is, in drive circuit 40, amplifier 40a supplies a drive current to coil 26, which serves to apply a drive force for adjusting the stylus pressure to tone arm 4, in response to the signal level of the analog control signal. In this embodiment, the resistance values of resistors 41 and 43 for setting the gain of amplifier 40a are adjusted in advance so that the actual stylus pressure accurately corresponds to the displayed value from digital indicator 68. It is appreciated that even though the control voltage produced by variable resistor 60 may be changed by a small amount, if this change does not result in a change in the digital representation produced by A/D converter 62, there will no change in the analog level produced by D/A converter 65. For example, if the setting of variable resistor 60 produces a control voltage corresponding to the stylus pressure and A/D converter 62 produces a digital representation of this stylus pressure, this digital representation is stored in latching circuit 64. D/A converter 65 re-converts this digital representation of stylus pressure to a corresponding analog level which is supplied to drive circuit 40, whereupon the energizing current applied to drive coil 26 by the drive circuit results in a corresponding analog pressure. Let it be assumed that the setting of variable resistor 60 is changed so as to produce a control voltage corresponding to a stylus pressure which varies by a small amount which is below the resolution of the A/D converter. Hence, even though the control voltage level corresponds to this new stylus pressure, A/D converter 62 will continue to produce a digital representation of the previous stylus pressure. This previous digital representation of stylus pressure is stored in latching circuit 64 and is reconverted by D/A converter 65 to an analog level corresponding to the previous stylus pressure. Therefore, even though the setting of variable resistor 60 may be changed, if this change is below the resolution of A/D converter 62, the fact that there will be no corresponding change in the digital representation of the control voltage means that the displayed stylus pressure, which is derived from the digital representation produced by A/D converter 62, will be equal to the actual stylus pressure which is exerted on the record disc and which is determined by the energizing current produced by drive circuit 40 which, in turn, is a function of the digital representation produced by A/D converter 62.
In the described above embodiment of the stylus-pressure adjusting and displaying circuit, the control voltage from variable resistor 60 is fed to A/D converter 62 where it is converted into the digital representation or control signal, used to perform both the stylus-pressure adjusting operation and display the stylus-pressure setting value. A graphical representation of the relationship between the displayed/actual stylus pressure and the setting of variable resistor 60 is depicted in FIG. 6. In FIG. 6 the ordinate represents both actual stylus and displayed stylus pressure, while the abscissa represents the setting of variable resistor 60. By reason of D/A converter 65, it is recognized that the actual stylus pressure, that is, the stylus pressure determined by the energization current supplied to coil 26 by drive circuit 40, remains constant over a small, discrete range of resistor settings. That is, although the effective resistance value of variable resistor 60 may change continuously, the actual stylus pressure exerted on the record disc is changed in discrete, step-wise manner. The small range over which a change in the resistor setting does not result in a corresponding change in the actual stylus pressure represents the resolution, or responsiveness, of A/D converter 62. Since, as is apparent from FIG. 6, the actual stylus pressure is dependent upon a change in the digital representation produced by A/D converter 62, and since the displayed stylus pressure is dependent upon this same change, digital display 68 thus displays the correct actual stylus pressure which is exerted by stylus 8 on record disc 31. The display error associated with the embodiment shown in FIG. 4 thus is avoided by the embodiment of FIG. 5. This display error is represented by the broken line in FIG. 6 which represents the relationship between actual stylus pressure and the setting, or effective resistance, of the variable resistor (i.e., variable resistor 42). This relationship, as represented by the broken line, is superimposed onto the relationship between the displayed stylus pressure and the resistor setting, as represented by the step-wise graph. It is recognized that the broken line representing actual stylus pressure intersects the solid line representing displayed stylus pressure only at discrete points. For resistor settings that differ from such discrete points, the displayed stylus pressure either is more or less than the actual stylus pressure. That is, to the left of the point at which the step-wise graph intersects the broken line, the displayed stylus pressure is less than the actual stylus pressure; and to the right of such point, the displayed stylus pressure is greater than the actual stylus pressure. If each step of the solid step-wise graph corresponds to 0.1 gram, the maximum display error either is +0.05 gram (to the right of the intersection of the rising solid line and the broken line) or -0.05 gram (to the left of the intersection of the rising solid line and the broken line). In the FIG. 4 embodiment, the graph representing actual stylus pressure differs from the graph representing displayed stylus pressure. In the FIG. 5 embodiment, the graph representing actual stylus pressure is coincident with the graph representing displayed stylus pressure. Thus, in the FIG. 5 embodiment, the display error is avoided.
As apparent from the above description of the embodiments of this invention, stylus pressure can be adjusted, as desired, even during a reproducing operation of the record playing device, by adjusting variable resistor 42 or 60. At the same time, the stylus pressure is concurrently displayed in a digital manner, such as on the panel front surface. Accordingly, the stylus pressure at that time can be easily confirmed,
Having described specific preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.
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Apparatus for adjusting and displaying the stylus pressure exerted on a record disc by a stylus carried by a tone arm in a record playing device comprises a vertical drive motor for bi-directionally driving the tone arm in the vertical direction, an adjusting circuit, such as an adjustable resistor, producing a control signal whose level is determinative of the stylus pressure, an energizing circuit responsive to the control signal for energizing the vertical drive motor in accordance with the level of the control signal, thereby establishing the stylus pressure, and a display device, such as a digital display, responding to the control signal for providing a visual display of the stylus pressure as determined by the level of the control signal.
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